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Sample records for central mexico metallogenic

  1. ALPINE MAGMATIC-METALLOGENIC FORMATIONS OF THE NORTHWESTERN AND CENTRAL DINARIDES

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    Jakob Pamić

    1997-12-01

    Full Text Available In the paper are presented basic geological, petrologieca1, geochemi-cal and mineral deposit data for five main magmatic-metallogenic formations of the northwestern and central Dinarides: (lThe Permo Triassic rifting related andesite-diorite formations; (2 The Jurassic-Lower Cretaceous accretionary (ophiolite formations; (3 The Upper Cretaceous-Paleogene subduction related basalt-rhyohite formations; (4 The Paleogene collisional granite formations, and (5 The Oligo-cene-Neogene postsubduction andesite formations. All these magmatic-metallogenic formations originated in different geotectonic settings during the Alpine evolution of the Dinaridic parts of thc Tethys and the postorogenic evolution of the Paratethys and the Pannonian Basin, respectively.

  2. Temporal evolution of granitic magmas in the Luanchuan metallogenic belt, east Qinling Orogen, central China: Implications for Mo metallogenesis

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    Li, Dong; Han, Jiangwei; Zhang, Shouting; Yan, Changhai; Cao, Huawen; Song, Yaowu

    2015-11-01

    The Luanchuan metallogenic belt, located within the eastern part of the Qinling Orogen, central China, hosts a number of world-class Mo deposits that are closely related to small late Mesozoic granitic plutons. Zircon U-Pb dating of distinct plutons in the Luanchuan metallogenic belt has yielded ages of 153 ± 1, 154 ± 2, 152 ± 2, and 148 ± 1 Ma. Molybdenite Re-Os isotopic compositions of Yuku ore district in the southern part of Luanchuan metallogenic belt has yielded an isochron age of 146 ± 1 Ma, which is consistent with the large-scale mineralization ages in the northern part of the Luanchuan metallogenic belt. A combination of previous studies and new geochronological and isotopic data show a concordant temporal and genetic link between granitic magmatism and Mo mineralization in the Luanchuan metallogenic belt, suggesting that this mineralization episode formed the most extensive Mo mineralization belt in the east Qinling Orogen. Zircon grains from Mo-related granitic plutons show similar trace element distributions. High-precision Multi Collector-Inductively Coupled Plasma-Mass Spectrometry (MC-ICP-MS) Pb isotope analysis of K-feldspar megacrysts from mineralization-related granites suggest that they were derived from the lower crust. Similarly, the Pb isotopic compositions of pyrite coprecipitated with molybdenite also suggest that the metals were derived form the lower crust, with probably minor mantle contribution. A continuum mineralization model that describes the sourcing of Mo from an evolving granitic magma over successive differentiation events, possibly in separate but connected magma chambers, could explain the remarkable Mo enrichment in the Luanchuan metallogenic belt. The volatile- and Mo-bearing granitic magmas ascended as diapirs from the deep crust, and were emplaced as dikes in the upper crust. Lithological differences between these Mo-bearing granites may relate to different stages in the evolution of individual magmas. Finally, ore

  3. An air quality model for Central Mexico

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    Jazcilevich, D. Aron; Garcia, R. Agustin; Suarez, Gerardo Ruiz; Magana, R. Victor; Perez, L. Jose Luis [Universidad Nacional Autonoma de Mexico, Centro de Ciencias de la Atmosfera, Mexico City (Mexico); Fuentes-Gea, Vicente [Universidad Nacional Autonoma de Mexico, Div. de Estudios del Posgrado, Mexico City (Mexico)

    1999-07-01

    A computational air quality model for Central Mexico that includes the Basin of the Valley of Mexico, the Valleys of Toluca, Puebla and Cuernavaca already in experimental operation, is presented. The meteorology of the region is obtained combining two non-hydrostatic models: a model designed for synoptic scales called MM5 provides initial and boundary data to a model specially designed for urban environments and scales called MEMO. The transport model used numerical techniques developed by the authors that eliminate numerical diffusion and dispersion. For the photochemical model several ODE's integrators were tested. The emissions model developed uses the latest inventory data gathered in the region. (Author)

  4. Research on Superimposed Metallogenic System

    Institute of Scientific and Technical Information of China (English)

    Zhai Yusheng; Wang Jianping; Deng Jun; Peng Runmin

    2004-01-01

    As located in the junction of three tectonic plates (the Eurasian plate, the Indian plate and the west Pacific plate), the China continent shows complex regional metallogenic features due to tectonic evolution of "micro-plates, polycycle tectonic movements". Well developed superimposed metallogenic systems have constituted one of the regional metallogenic features in China. Through the study on superimposed metallogenic system of the middle and lower reaches of the Yangtze River and of the Yuebei basin (northern Guangdong Province), the authors put forward some basic combination pattern of sedimentary-magmatic superimposed metallogenic system and summarize its forming conditions (controlling factors).

  5. Classic to postclassic in highland central Mexico.

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    Dumond, D E; Muller, F

    1972-03-17

    The data and argument we have presented converge on three points. 1) With the decline and abandonment of Teotihuacan by the end of the Metepec phase (Teotihuacan IV), the valleys of Mexico and of Puebla-Tlax-cala witnessed the development of a ceramic culture that was represented, on the one hand, by obvious Teotihuacan derivations in presumably ritual ware and possible Teotihuacan derivations in simpler pottery of red-on-buff, and, on the other hand, by elements that seem to represent a resurgence of Preclassic characteristics. Whether the development is explained through a measure of outside influence or as a local phenomenon, the direct derivation of a substantial portion of the complex from Classic Teotihuacan is unmistakable. This transitional horizon predated the arrival of plumbate tradeware in highland central Mexico. 2) The transitional horizon coincided with (and no doubt was an integral part of) an alteration of Classic settlement patterns so drastic that it must bespeak political disruption. Nevertheless, there is no evidence that the Postclassic center of Tula represented a significant force in the highlands at that time. There is no evidence that the center of Cholula, which may even have been substantially abandoned during the previous period, was able to exert any force at this juncture; it appears more likely that Cholula was largely reoccupied after the abandonment of Teotihuacan. There is no direct evidence of domination by Xochicalco or any other known major foreign center, although some ceramic traits suggest that relatively minor influences may have emanated from Xochicalco; unfortunately, the state of research at that center does not permit a determination at this time. Thus the most reasonable view on the basis of present evidence is that the abandonment of Teotihuacan was not the direct result of the strength of another centralized power, although some outside populations may have been involved in a minor way. Whatever the proximate cause

  6. Ground Motion in Central Mexico: A Comprehensive Analysis

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    Ramirez-Guzman, L.; Juarez, A.; Rábade, S.; Aguirre, J.; Bielak, J.

    2015-12-01

    This study presents a detailed analysis of the ground motion in Central Mexico based on numerical simulations, as well as broadband and strong ground motion records. We describe and evaluate a velocity model for Central Mexico derived from noise and regional earthquake cross-correlations, which is used throughout this research to estimate the ground motion in the region. The 3D crustal model includes a geotechnical structure of the Valley of Mexico (VM), subduction zone geometry, and 3D velocity distributions. The latter are based on more than 200 low magnitude (Mw Valley of Mexico originating from intra-slab deep events and temblors located along the Pacific coast. Also, we quantify the effects Trans-Mexican Volcanic Belt (TMVB) and the low-velocity deposits on the ground motion. The 3D octree-based finite element wave propagation computations, valid up to 1 Hz, reveal that the inclusion of a basin with a structure as complex as the Valley of Mexico dramatically enhances the regional effects induced by the TMVB. Moreover, the basin not only produces ground motion amplification and anomalous duration, but it also favors the energy focusing into zones of Mexico City where structures typically undergo high levels of damage.

  7. A roe deer from the Pliocene of Hidalgo, central Mexico

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    Eduardo Jiménez-Hidalgo

    2015-12-01

    Full Text Available Mexican Pliocene cervids are very poorly known. We report on new fossil material of the roe deer Capreolus constantini recovered from the Pliocene Atotonilco El Grande Formation of Santa María Amajac, Hidalgo (central Mexico. The specimens were collected from a series of layers of friable to moderately indurated polymictic conglomerate supported by a sandstone-tuffaceous-calcareous matrix. This species was formerly known only from the late Pliocene of Udunga, Russia, thus implying a dispersal event to North America around 4.0 Ma. This cervid is one of the very small number of mammals recorded from the poorly sampled Pliocene temperate deposits of Mexico.

  8. 1996 Central New Mexico Section [American Chemical Society] annual report

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    Cournoyer, M.E. [Los Alamos National Lab., NM (United States). Chemistry Science and Technology Div.

    1997-02-07

    The main goal of the Central New Mexico Section this year was to increase attendance at the local meetings. Throughout the course of the year attendance at the meeting more than doubled. This was brought on by several factors: having the meeting spread throughout the section (Albuquerque, Santa Fe, Las Vegas, Socorro, Los Alamos); supplementing the ACS National Tour speakers with interesting local sections speakers; and making full use of the newly formed Public Relations Committee. Activities during 1996 are summarized.

  9. , Recorded at Ladron Peak, Central New Mexico

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    Ricketts, J. W.; Kelley, S.; Read, A. S.; Karlstrom, K. E.

    2010-12-01

    Ladron Peak, situated on the western flank of the Rio Grande rift ~30 miles NW of Socorro, NM, is composed of Precambrian granitic and metamorphic assemblages that have been faulted and uplifted during the late Tertiary formation of the rift. The area is bounded on three sides by normal faults, including the anomalously low-angle (~26°) Jeter fault to the east, which places Precambrian rocks in the footwall against Paleozoic and Mesozoic fault slivers, and mainly Cenozoic Santa Fe Group basin fill in the hanging wall. New apatite fission track (AFT) thermochronological data collected at 22 locations along the NE and SE margins of Ladron Peak give a range of ages from 10.9 ± 1.9 to 20.4 ± 8.6 Ma. Samples within the footwall include granitic and metasedimentary rocks that have mean track lengths of 13.1 to 14.1 μm; one quartzite sample has a mean track length of 12.5 μm, suggesting time in the partial annealing zone. Within the hanging wall block, new AFT ages from the Permian Bursum and Abo Formations give cooling ages of 23.1 ± 3.3 Ma. and 59.9 ± 12.4 Ma., respectively. The Bursum Formation sample, with a track length of 13.7 μm, cooled below the 110°C isotherm during the Miocene, while the Abo Formation sample, with a track length of 11.2 μm, was only partially reset prior to rift-related deformation. Mylonitized granitic and metamorphic rocks in the immediate footwall preserve dip-slip lineations that are parallel to slip on the Jeter fault. This suggests that strain associated with exhumation was recorded by both brittle and ductile deformation. Although this type of deformation is common within metamorphic core complexes in highly extended terranes, ductile normal faulting has not been recognized within the Rio Grande rift in New Mexico, though there is some suggestion of ductile deformation around Blanca Peak in the San Luis Valley in Colorado. These observations imply one or both of the following: (1) Ductile deformation at Ladron Peak was

  10. Gray fox (Urocyon cinereoargenteus) parasite diversity in central Mexico.

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    Hernández-Camacho, Norma; Pineda-López, Raúl Francisco; de Jesús Guerrero-Carrillo, María; Cantó-Alarcón, Germinal Jorge; Jones, Robert Wallace; Moreno-Pérez, Marco Antonio; Mosqueda-Gualito, Juan Joel; Zamora-Ledesma, Salvador; Camacho-Macías, Brenda

    2016-08-01

    Mexico has a long history of parasitological studies in communities of vertebrates. However, the mega diversity of the country makes fauna inventories an ongoing priority. Presently, there is little published on the parasite fauna of gray foxes (Urocyon cinereoargenteus Schereber, 1775) and this study provides new records of parasites for gray foxes in central Mexico. It is a continuation of a series of previous parasitological studies conducted with this carnivore in Mexico from 2003 to the present. A total of 24 foxes in the Parque Nacional El Cimatario (PANEC) were trapped, anaesthetized, and parasites recovered. The species found were Dirofilaria immitis, Ctenocephalides canis, C. felis, Euhoplopsillus glacialis affinis (first report for gray foxes in Mexico) Pulex simulants, and Ixodes sp. Three additional gray fox carcasses were necropsied and the parasites collected were adult nematodes Physaloptera praeputialis and Toxocara canis. The intensive study of the gray fox population selected for the 2013-2015 recent period allowed for a two-fold increase in the number of parasite species recorded for this carnivore since 2003 (nine to 18 parasite species), mainly recording parasitic arthropods, Dirofilaria immitis filariae and adult nematodes. The parasite species recorded are generalists that can survive in anthropic environments; which is characteristic of the present ecological scenario in central Mexico. The close proximity of the PANEC to the city of Santiago de Queretaro suggests possible parasite transmission between the foxes and domestic and feral dogs. Furthermore, packs of feral dogs in the PANEC might have altered habitat use by foxes, with possible impacts on transmission.

  11. Gray fox (Urocyon cinereoargenteus parasite diversity in central Mexico

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    Norma Hernández-Camacho

    2016-08-01

    Full Text Available Mexico has a long history of parasitological studies in communities of vertebrates. However, the mega diversity of the country makes fauna inventories an ongoing priority. Presently, there is little published on the parasite fauna of gray foxes (Urocyon cinereoargenteus Schereber, 1775 and this study provides new records of parasites for gray foxes in central Mexico. It is a continuation of a series of previous parasitological studies conducted with this carnivore in Mexico from 2003 to the present. A total of 24 foxes in the Parque Nacional El Cimatario (PANEC were trapped, anaesthetized, and parasites recovered. The species found were Dirofilaria immitis, Ctenocephalides canis, C. felis, Euhoplopsillus glacialis affinis (first report for gray foxes in Mexico Pulex simulants, and Ixodes sp. Three additional gray fox carcasses were necropsied and the parasites collected were adult nematodes Physaloptera praeputialis and Toxocara canis. The intensive study of the gray fox population selected for the 2013–2015 recent period allowed for a two-fold increase in the number of parasite species recorded for this carnivore since 2003 (nine to 18 parasite species, mainly recording parasitic arthropods, Dirofilaria immitis filariae and adult nematodes. The parasite species recorded are generalists that can survive in anthropic environments; which is characteristic of the present ecological scenario in central Mexico. The close proximity of the PANEC to the city of Santiago de Queretaro suggests possible parasite transmission between the foxes and domestic and feral dogs. Furthermore, packs of feral dogs in the PANEC might have altered habitat use by foxes, with possible impacts on transmission.

  12. Association of Drought with Typhus Epidemics in Central Mexico

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    Acuna-Soto, R.; Stahle, D.; Villanueva Diaz, J.; Therrell, M.

    2007-05-01

    Typhus is an acute infectious disease caused by the bacteria Rickettsia prowazekii, which is transmitted among humans by the body lice (Pediculus humanus corporis). The disease is highly contagious and transmission is favored in populations living in crowded conditions. Under these circumstances, typhus transmission is facilitated by factors that favor the colonization and proliferation of body lice such as absence of personal hygiene and wearing the same clothes for long periods of time. Historically, periods of war and famine were associated with devastating epidemics with high mortality rates in many parts of the world. Central Mexico has a long record of typhus epidemics. In this region, at > 2000 meters above sea level, the disease was endemic and occurred with a seasonal pattern in winter, with occasional large epidemics. Recently, we completed a chronology of epidemics in Mexico. A total of 22 well-defined major typhus epidemics were identified between 1650 and 1920. All of them caused periods of increased mortality that lasted 2 - 4 years (more than one standard deviation from the previous ten year period). The record of typhus epidemics was evaluated against the tree-ring record of Cuauhtmoc La Fragua, Puebla. This chronology, based on Douglas fir, has demonstrated to be a faithful record of precipitation in central Mexico. The results indicate that a statistically significant drought (t test, p < .05) prevailed during the first year of all 22 large outbreaks of typhus in recent Mexican history. No distinction is made between times of peace and war. This indicates that drought alone was capable of inducing the social conditions for increased transmission of typhus in pre-industrial central Mexico.

  13. Curie depth vs. flat subduction in Central Mexico

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    Manea, Marina; Constantin Manea, Vlad

    2010-05-01

    Forearcs located above active subduction zones are generally characterized by low heat flow values, and this is considered a consequence of the subduction of cold slabs beneath continental plates. In the case of Central Mexico, the geometry of the subducting Cocos plate is quite unusual, the slab runs flat for several hundreds of kilometers before plunging into the asthenosphere. This particular geometry has a strong influence on the temperature distribution of the overriding plate where very low heatflow values are recorded (15-30 mW/m2). In this paper we use the aeromagnetic map of Mexico in order to infer the maximum depth of magnetic source, regarded as Curie depth and corresponding to a temperature of 575-600C°. Our spectral analysis revealed the existence of a deep magnetic source (30-40 km). We compare these results with the thermal structure associated with flat slab subduction in the area. We obtained a good agreement between the two estimates and we conclude that flat slab subduction in Central Mexico controls the maximum depth of magnetic sources in the overriding plate.

  14. Regional geothermal exploration in north central New Mexico. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Icerman, L. (ed.)

    1984-02-01

    A broad-based geothermal resource reconnaissance study covering Bernalillo, Los Alamos, Rio Arriba, San Miguel, Sandoval, Santa Fe, Taos, Torrance, and Valencia counties in north central New Mexico was conducted from June 15, 1981, through September 30, 1983. Specific activities included the compilation of actual temperature, bottom-hole temperature gradient, and geotemperature data; tabulation of water chemistry data; field collection of temperature-depth data from existing wells; and drilling of temperature gradient holes in the Ojo Caliente, San Ysidro, Rio Puerco, and Polvadera areas. The data collected were used to perform: (1) a regional analysis of the geothermal energy potential of north central New Mexico; (2) two site-specific studies of the potential relationship between groundwater constrictions and geothermal resources; (3) an evaluation of the geothermal energy potential at Santa Ana Pueblo; (4) a general analysis of the geothermal energy resources of the Rio Grande Rift, including specific data on the Valles Caldera; and (5) an evaluation of the use of geothermometers on New Mexico groundwaters. Separate abstracts were prepared for individual chapters.

  15. ECAIM : Air Quality Studies and its Impact in Central Mexico.

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    Ruiz-Suárez, L. G.; Torres, R.; Garcia-Reynoso, J. A.; Zavala-Hidalgo, J.; Grutter, M.; Delgado-Campos, J.; Molina, L. T.

    2014-12-01

    Mexico City Metropolitan Area has been the object of several well know intensive campaigns. Since MARI (1991) , IMADA (1997), MCMA 2003 and MILAGRO (2006). The spatial scope of these studies have gone from urban to regional to continental, with the focus on MCMA as an emissions source. During MILAGRO, the influence on MCMA of wildfires and agricultural biomass burning around the megacity was considered. However, around Mexico City a crown of metropolis and middle size cities make a region known as the Central Mexico Regional Crow (CRCM for its acronym in Spanish language) or Central Mexico City Belt. It contains 32 million inhabitants and produces 40% of national gross product. The region undergoes an uncontrolled urban sprawl. Evidence is building-up on complex air pollution transport processes between the air basins within CRCM. However, only MCMA counts with reliable long-term records of criteria pollutants monitoring. Only few intensive campaigns have been done in the air basins surrounding MCMA. ECAIM project has several goals: a) To use ground and satellite observations to assess emissions inventories; b) To use ground and satellite observations to assess the performance of air quality models for the whole region; c) to produce critical levels exceedence maps; d) To produce a preliminary diagnostic of air quality for the CRCM; e) to produce a preliminary estimate of the cost of air pollution within the CRCM. In this work we show the method approach to use the best available information from local AQM networks, field campaigns, satellite observations and modeling to achieve those goals. We show some preliminary results.

  16. Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico)

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    Lenhardt, Nils; Götz, Annette E.

    2015-04-01

    The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

  17. Climbing in the high volcanoes of central Mexico

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    Secor, R. J.

    1984-01-01

    A chain of volcanoes extends across central Mexico along the 19th parallel, a line just south of Mexico City. The westernmost of these peaks is Nevado de Colima at 4,636 feet above sea level. A subsidiary summit of Nevado de Colima is Volcan de Colima, locally called Fuego (fire) it still emits sulphurous fumes and an occasional plume of smoke since its disastrous eruption in 1941. Parictuin, now dormant, was born in the fall of 1943 when a cornfield suddenly erupted. Within 18 months, the cone grew more than 1,700 feet. Nevado de Toluca is a 15,433-foot volcanic peak south of the city of Toluca. Just southeast of Mexico City are two high volcanoes that are permanently covered by snow: Iztaccihuatl (17,342 fet) and Popocatepetl (17,887 feet) Further east is the third highest mountain in North America: 18,700-foot Citlateptl, or El Pico de Orizaba. North of these high peaks are two volcanoes, 14, 436-foot La Malinche and Cofre de Perote at 14,048 feet. This range of mountains is known variously as the Cordillera de Anahuac, the Sierra Volcanica Transversal, or the Cordillera Neovolcanica. 

  18. Characteristics of the Central Mexico Intermediate-Depth Earthquakes

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    Yamamoto, J.; Quintanar, L.; Jimenez, Z.

    2001-12-01

    Moderate magnitude but damaging earthquakes occur frequently in the central part (18o N) of Mexico along an east-west limited (96o to 99o W) narrow belt. From 1928 through 2000 this region of western Guerrero and Puebla-Oaxaca has been the site of nine intermediate depth earthquakes of similar characteristics, normal faulting and a notable extent of felt area and damage northwestern of the epicenters. Earthquakes in this area are very important since they occur in the most populated region of Mexico and they are used frequently in the discussion of the feasibility of the seismic cycle hypothesis. In the present paper we made an overall analysis of the earthquakes to find out common features in an attempt to characterize the earthquakes of the region. Special emphasis is place on the 1980, 1999 and 2000 earthquakes since they are best documented. Recorded acceleration amplitudes of the Puebla earthquake of June 15, 1999 a typical earthquake of this region, show a clear enhancement in the frequency range of 0.06 Hz to 6.0 Hz that can be up to eight times higher toward the northwest of the epicenter as compared to the opposite direction. This feature, that seems common to earthquakes in the region can not be fully explained by the involved rupture processes. Therefore, we investigate the possibility that the apparent directivity could be due to a regional propagation effect by analyzing the Lg coda decay. Our result explains however, only partially the observed feature. We especulate that probably the presence to the north of the Transmexican Volcanic Belt plays an important role in controlling the enhancement of low frequency seismic signals and other features of the Central Mexico earthquakes.

  19. Causes and impacts of the deportation of Central American immigrants from the United States to Mexico

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    Simón Pedro Izcara Palacios

    2015-01-01

    Full Text Available Over the last decade, the number of immigrants deported from the United States to Mexico based on an order of removal has hearly doubled. Not all migrants removed to Mexico are Mexican citizens, some are Central America citizens. This article, usins qualitative methods that includes in-depth interviews with 75 Central American migrants who were deported from the United States, examines the causes and impacts of the deportation of Central American immigrants from United States to Mexico and concludes that these deportations led to increase in violence in Mexico.

  20. Analysis of gravity data in Central Valleys, Oaxaca, southern, Mexico

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    Gonzalez, T.; Ferrusquia, I.

    2015-12-01

    The region known as Central Valleys is located in the state of Oaxaca, southern, Mexico (16.3o- 17.7 o N Lat. and 96 o - 97 o W Long.) In its central portion is settled the capital of the state. There are very few published detailed geological studies.. Geomorphological and geological features, indicates that Central Valleys and surrounding mountains conform a graben structure. Its shape is an inverted Y, centred on Oaxaca City. The study area was covered by a detailed gravity survey with a homogenous distribution of stations. The Bouguer gravity map is dominated by a large gravity low, oriented NW-SE. In order to know the characteristics of anomalies observed gravity, data transformations were used. The use of spectral methods has increased in recent years, especially for the estimation of the depth of the source. Analysis of the gravity data sheds light on the regional depth of the Graben basement and the spatial distribution of the volcanic rocks

  1. Evaporation rates of pasture-mesquite vegetation in central Mexico

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    Sosa, E. G.; Escobar, A. G.

    2004-12-01

    The semiarid highlands of Queretaro, in central Mexico, are characterized by booming urban and industrial developments with increasing demand for water. Agriculture takes place in the valleys and the surrounding hills have different types of xeric to subtropical rangeland. Hills are unfit for agriculture and usually are managed for cattle production and fuelwood. However, recent studies suggest that some hill areas are important for groundwater recharge and if they are not protected, important water shortages are envisioned. A critical question involves the effects of land management practices on rangeland hydrologic processes. Evaporation (E), which includes plant and soil evaporation is the largest water loss from rangelands and few data are available for central Mexico. The objective of this study was to estimate E from a mesquite (Prosopis sp.) dominated vegetation using the eddy correlation and the Pennman-Monteith models. Measurements were made during 24 summer days of 2004 at a piedmont site at Amascala, Queretaro (1919 m, 20° 41' N, 100° 16' W). Long term annual rainfall is 568 ± 137 mm. Shrub density was 770 plants per hectare and mean height was 1.8 m. The understory was composed by a mixture of annual and perennial grasses but their biomass was negligible. Agroforestry was the current land use of the site. Shrubs were pruned every 2 or 3 years to maintain its height and promote leafty regrowth. Goats usually browsed the mesquite canopy, but during the time of the study they were excluded from the area.The rainy season started on 15 May and measurements initiated on 1 June, five days after a severe hail storm. Although the mesquite canopy had a full developed canopy with leaf area index of 3.2 by this time, they lost approximately 70% of leaf area. May and June rainfall was 146 mm and 46 mm occurred during the measuring period. Throughout the measurement period E was coupled to global radiation and total evaporation was 73.8 mm. On cloudy days E ranged

  2. Evaporation from groundwater discharge playas, Estancia Basin, central New Mexico

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    Menking, Kirsten M.; Anderson, Roger Y.; Brunsell, Nathaniel A.; Allen, Bruce D.; Ellwein, Amy L.; Loveland, Thomas A.; Hostetler, Steven W.

    2000-07-01

    Bowen ratio meteorological stations have been deployed to measure rates of evaporation from groundwater discharge playas and from an adjacent vegetated bench in the Estancia Basin, in central New Mexico. The playas are remnants of late Pleistocene pluvial Lake Estancia and are discharge areas for groundwater originating as precipitation in the adjacent Manzano Mts. They also accumulate water during local precipitation events. Evaporation is calculated from measured values of net radiation, soil heat flux, atmospheric temperature, and relative humidity. Evaporation rates are strongly dependent on the presence or absence of standing water in the playas, with rates increasing more than 600% after individual rainstorms. Evaporation at site E-12, in the southeastern part of the playa complex, measured 74 cm over a yearlong period from mid-1997 through mid-1998. This value compares favorably to earlier estimates from northern Estancia playas, but is nearly three times greater than evaporation at a similar playa in western Utah. Differences in geographical position, salt crust composition, and physical properties may explain some of the difference in evaporation rates in these two geographic regions.

  3. Ground-based Fourier transform infrared spectroscopy in central Mexico

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    Plaza, Eddy; Stremme, Wolfgang; Bezanilla, Alejandro; Baylon, Jorge; Grutter, Michel; Blumenstock, Thomas; Hase, Frank

    2014-05-01

    Altzomoni is a high altitude station in central Mexico (19.12 N, 98.65 W, 4000 m a.s.l.) for continuous measurements of various atmospheric parameters. It is located within the Izta-Popo National Park and is operated remotely from the UNAM campus. Since May 2012, high resolution solar absorption spectra have been recorded from this site using a FTIR from Bruker (HR120/5) equipped with MCT, InSb and InGaAs detectors and various optical filters. In this contribution we present a detailed description of the measurement site and the instrumental set-up including a record of the instrumental line-shapes (modulation efficiency and phase error) obtained from cell measurements and analyzed with the LINEFIT code. A preliminary analysis of almost two years of spectra recorded at the Altzomoni site resulting in profile retrievals of four NDACC gases O3, CO, HF and HCl is presented. The retrieval code PROFFIT is used and the Averaging Kernels and an error analysis are used to describe the quality of the measurements. The annual cycles in the time series of O3 and CO are presented and discussed, as well as some examples of anomalies due to volcanic gas emissions of HF and HCl are shown. The presented work is part of an effort to certify this station as part of the NDACC international network.

  4. Seismicity surveying in central and north mexico region

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    Gómez, J. M.; Guzmán, M.; Nieto, A.; Zúñiga, R.; Alaniz, S.; Barboza, R.

    2003-04-01

    The seismic nature of Central Mexico is poorly understood due to insufficient sampling. This region is characterized by a very low deformation rate. The seismic activity is variable and ranges from microseismicity to large earthquakes. Some large earthquakes have occurred with an unknown returning period; structural studies show this recurrence could range from hundreds to thousands of years. Some authors argue that there is not connection between ancient and recent activity. We carried out several seismic surveys in part of the TransMexican Volcanic Belt (TMVB) and the Altiplano Central. We installed a temporal network, in order to record spatial seismic distribution. This network consists of 3-5 short period instruments, consisting of triaxial digital velocity recorders (0.01-4.5 Hz). We registered several swarms; one took place in Guanajuato and lasted for 2 weeks. Another crisis occurred at the northern limit of the TMVB at Sierra Gorda. Over five weeks several micro-earthquakes M < 2 were felt with anomaously high intensity. Relocated seismicity shows very shallow (< 10km) activity. The regional crust conditions appear to be roughly uniform even though the seismicity varies significantly. In some cases like seismic swarms, several microearthquakes are aligned, and seem to be quasi-parallel to the direction of the fault strike, some other times they are perpendicular. However, surface ruptures associated to earthquakes are not observed to confirm this. Then, a challenge is to locate the seismogenic structures, basically because of the surface structures are too old to be still active. Increased seismotectonic knowledge of this region may give further insight into the details of the interaction between surface structures driven by the regional stress field.

  5. Seismicity Surveying in Central and North Mexico Regions

    Science.gov (United States)

    Nieto-Samaniego, A.; Gomez-Gonzalez, J. M.; Guzman-Speziale, M.; Zuniga, R.; Alaniz-Alvarez, S.; Barboza, R.; Davalos, O.

    2003-12-01

    The seismic nature of Central Mexico is poorly understood due to insufficient sampling. We carried out a seismic survey in part of the TransMexican Volcanic Belt (TMVB) and the Central Altiplano. These regions are characterized by a very low deformation rates. Seismic activity is variable and ranges from microseismicity to large earthquakes, but no large historic earthquake has been instrumentally recorded. Only few direct observations such as intensity reconstructions and recent paleoseismic studies (e.g. the Acambay-Tixmadej earthquake of 1912) are available. Large earthquakes have occurred but their recurrence period is unknown; structural studies show this recurrence could range from hundreds to thousands of years. In order to understand the regional seismic behavior, we installed a temporal network. This network consists of 3-5 short period instruments, consisting of 16-bits triaxial digital velocity recorders (0.01-4.5 Hz). We registered several seismic sequences over a period of several months. One of them took place in Guanajuato within a graben structure in the TMVB and lasted for 2 weeks. Another sequence occurred at the northern limit of the TMVB in the Sierra Gorda. Over five weeks, several micro-earthquakes M Sierra Gorda, the event distribution is aligned along a small valley, but perpendicular to the main structural grain imposed by the Sierra Madre Oriental range. In no instances have surface ruptures been observed; those seismogenic structures could be blind ones. A challenge is to locate this structures which are may be too old to be still active. Increased seismotectonic knowledge of this region will yield further insight into the details of the interaction between surface structures driven by the regional stress field. Our results provide evidence that the region requires more intensive seismic surveying, and in some cases that some structures have been reactivated recently.

  6. BLM/OCS Ecological Investigations of Petroleum Production Platforms in the Central Gulf of Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ecological Investigations of Petroleum Production Platforms in the Central Gulf of Mexico Project was conducted by Texas A and M University under contract to...

  7. Patterns of illness in travelers visiting Mexico and Central America: the GeoSentinel experience

    OpenAIRE

    Flores-Figueroa, J; Okhuysen, P C; von Sonnenburg, F.; DuPont, H L; Libman, M D; Keystone, J S; Hale, D C; Burchard, G.; Han, P V; Wilder-Smith, A; Freedman, D O

    2011-01-01

    BACKGROUND: Mexico and Central America are important travel destinations for North American and European travelers. There is limited information on regional differences in travel related morbidity. METHODS: We describe the morbidity among 4779 ill travelers returned from Mexico and Central America who were evaluated at GeoSentinel network clinics during December 1996 to February 2010. RESULTS: The most frequent presenting syndromes included acute and chronic diarrhea, dermat...

  8. Transition on the Geometry of the Cocos Plate in Central-Southern Mexico.

    Science.gov (United States)

    Rodríguez-Domínguez, M. Á.; Perez-Campos, X.; Valencia-Cabrera, D.; Clayton, R. W.; Cordoba-Montiel, F.; Valdes-Gonzales, C. M.; Brudzinski, M. R.; Cabral-Cano, E.; Arciniega-Ceballos, A.

    2014-12-01

    The tectonic setting, produced by the interaction between the Cocos and North American plates, follows complex geometries along the Pacific coast. Previous studies in central Mexico showed that the slab dips nearly horizontally before steeply subducting into the continental mantle; in contrast, in southern Mexico, the slabs dips under the continental plate at a constant angle. Receiver functions from four seismic networks: GECO (Geometry of Cocos), SSN (Servicio Sismológico Nacional), OxNet (Oaxaca Network) and UV (Universidad Veracruzana) are used to study the crustal structure underneath the stations, and image the subducting Cocos plate in order to define the geometry and the transition angle in central-southern Mexico.

  9. [Production systems of Spondias purpurea (Anacardiaceae) in Central West Mexico].

    Science.gov (United States)

    Ramírez Hernández, Blanca C; Barrios Eulogio, Pimienta; Castellanos Ramos, Javier Z; Muñoz Urias, Alejandro; Palomino Hasbach, Guadalupe; Pimienta Barrios, Enrique

    2008-06-01

    Morphological, physical and chemical traits related with fruit quality characteristics of Spondias purpurea L. agroecosystems were studied in Central-West Mexico for wild and cultivated populations. Spondias purpurea regularly thrive in shallow, rocky infertile soils unsuitable for conventional crops. The weight, axial and radial length, pH, total soluble solids (SST), reducing sugars, proteins and mineral content in fruits were recorded. The mean fresh fruit weight was superior in the cultivated varieties (20 g) than in the wild (16 g). Similarly the highest values of pH, SST, reducing sugars and protein content (3.3, 12.15 degrees Brix, 0.38 g/100 g and 1.18 g/100 g, respectively) were observed in the cultivated plantations compared with wild populations (3.0, 8.31 degrees Brix, 0.24 g/100 g and 0.14 g/100 g, respectively). In cultivated plantations, productivity ranged from 0.15 ton ha(-1) to 5.0 ton ha(-1), and must be considered satisfactory, considering the low inputs of fertilizers and pesticides applied to orchards. The fruits of S. purpurea are similar in nutrimental content to more important commercial fruit species; it produces fresh fruits during the dry months of spring, when few fresh fruits are available in the local markets. In addition, S. purpurea is a source of water and food for domestic animals and wild fauna. These traits emphasize their agronomical and ecological importance for tropical and subtropical environments, where it can also be used in reforestation programs because it can grow in infertile rocky soils, and in agroecosystems inhabited by low income farmers that practice subsistence agriculture. In fact, the cultivation of Spondias has helped convert marginal lands into productive lands.

  10. Shrub Encroachment and Regional Climate Change in Central New Mexico

    Science.gov (United States)

    He, Y.; De Wekker, S.; D'Odorico, P.

    2011-12-01

    Shrub encroachment is a global ecological phenomenon that involves a decrease in grass cover and an increase in density and coverage of woody species in semi-desert area and is associated with a number of environmental change drivers. In Southwestern U.S., such a dramatic vegetation transition has been occurring since mid 19th century and has resulted in loss of ecosystem services. The change in vegetation cover affects the mass and energy exchange between the land surface and the atmosphere and can therefore impact local climate and contribute to regional climate change. In particular, nighttime warming has been observed in the shrub dominated landscapes near the encroaching front in winter months. This nighttime warming favors the successful establishment and survival of a certain shrub species, Larrea tridentata, because of its sensitivity to freezing induced mortality. As a result, further shrub encroachment may be facilitated by the nighttime warming, resulting in a positive vegetation-microclimate feedback. To assess the relative importance of the observed nighttime warming due to changes in vegetation cover compared to the background climate warming, we use historical climate records and output from regional climate models. Results show that the nighttime warming induced by shrub encroachment is equivalent to a change in regional climate warming over the last 40-70 years in central New Mexico. Moreover, we show results from atmospheric mesoscale model simulations with the goal to assess if the nighttime warming caused by differences in vegetation cover can be simulated. We need to ensure that the nighttime warming is simulated well, so that realistic regional climate simulations can be performed to predict the rate of shrub encroachment if facilitated only by the vegetation-microclimate feedback.

  11. 全球成矿域和成矿区带%Global metallogenic domains and districts

    Institute of Scientific and Technical Information of China (English)

    梅燕雄; 裴荣富; 杨德凤; 戴自希; 李进文; 徐丛荣; 瞿泓滢

    2009-01-01

    -Mongolia, Siberia and Sino-Ko-rea. it is characterized by large-scale mineralizations of natural gas, coals, iron, potash salt, oil, uranium, manganese, chromium, lead, zinc, nickel, tungsten, molybdenum, antimony, gold, silver, phosphorus and diamond. The metallogenic epochs run through all the geological ages, mainly Paleozoic and subordinately Mesozoic and Proterozoic. Lying in the southern part of the earth, the Gondwana metallogenic domain runs across South America, Africa, Oceania and Asia and comprises five gigantic metallogenic districts, namely, South America, Africa-Arabia, India, Australia and Antarctic. It is featured by large-scale mineralizations of oil, gas, bauxite, diamond, lead, zinc, copper, nickel, iron, gold, chromium, tin and uranium. The metallogenic epochs also go through all the geological ages, with Proterozoic and Cenozoic being dominant, and Archean and Mesozoic possessing the subordinate importance. Running across the central part of the earth, the Tethys metallogenic domain straddles North America, Europe, Africa and Asia and is made up of five gigantic metallogenic districts, namely, Caribbean, Mediterranean, West Asia, Himalaya and Indo-China Peninsula. It is characterized by large-scale mineralizations of tin, potash salt, lead, zinc, bauxite, copper and molybdenum. The metallogenic epochs are dominated by Mesozoic-Cenozoic. Distributed around the Pacific Ocean, the circum-Pacific metallo-genic domain straddles Asia, Oceania, North America and South America and consists of five gigantic metallogenic districts, namely, North Cordilleran, Andean, Chokochi-Okhotsk, East Asia and Irian-New Zealand. It is characterized by large-scale mineralizations of copper, molybdenum, gold, silver, nickel, tungsten, tin, lead and zinc. The most important metallogenic epochs are Mesozoic-Cenozoic.

  12. Geothermal Exploration of the Winston Graben, Central New Mexico, USA

    Science.gov (United States)

    Sophy, M. J.; Kelley, S. A.

    2011-12-01

    We are assessing the geothermal potential of the Winston Graben of central New Mexico using borehole temperature logs and geophysical data. The Winston Graben is a late Cenozoic rift basin, part of the larger Rio Grande rift, which is 5 to 10 km wide and 56 km long with northern and southern termini occurring at accommodation zones that coincide with late Cenozoic volcanic lineaments. The graben is interpreted to be symmetric based on geologic mapping, with 2 km of stratigraphic offset on both the western and eastern margins. The graben is bordered by the Black Range to the west and is separated from the Rio Grande valley by the Sierra Cuchillo, a horst block made of Paleozoic rocks intruded by a laccolith. Geothermal and geophysical data, including water table measurements, well temperature logs, thermal conductivity samples, bottom hole temperatures, water chemistry, and gravity data have been extracted from the New Mexico Geothermal Database, part of the National Geothermal Database, and the Geonet Gravity and Magnetic Dataset Repository. Combined with existing geologic maps of the Winston Graben and surroundings, these data help to identify spatial relationships between geologic structures and groundwater parameters and distribution. Geothermal gradients from industry temperature-depth well profiles range from 20°C/km to 60°C/km with a spatial distribution of higher gradients located on the eastern side of the Sierra Cuchillo horst, which is where a mapped warm spring is located. Lower thermal gradients were observed to the west in the groundwater recharge area of the basin. Analysis of Bouguer gravity data indicate a gravity low coinciding with the center of the Winston Graben, which is attributed to be the deepest part of the basin, symetrically surrounded by gravity highs. Gravity highs coincide with the middle Cenozoic Morenci and Chise volcanic lineaments along the northern and southern ends of the graben. The mapped warm spring occurs at the

  13. Cerro Xalapaxco: An Unusual Tuff Cone with Multiple Explosion Craters, in Central Mexico (Puebla)

    Science.gov (United States)

    Abrams, M. J.; Siebe, C.

    1994-01-01

    The Xalapaxco tuff cone is located on the northeast flank of La Malinche stratovolcano in central Mexico. An unusually large number (10) of explosion craters, concentrated on the central and on the uphill side of the cone, expose alternating beds of stratified surge deposits and massive fall deposits.

  14. The economic impact of Sandia National Laboratories on Central New Mexico and the State of New Mexico Fiscal Year 1998

    Energy Technology Data Exchange (ETDEWEB)

    Lansford, Robert R.; Adcock, Larry D.; Gentry, Lucille M.; Ben-David, Shaul; Temple, John

    1999-08-09

    Sandia National Laboratories (SNL) is a Department of Energy federally funded national security laboratory that uses engineering and science to ensure the security of the Nation. SNL provides scientific and engineering solutions to meet national needs in nuclear weapons and related defense systems, energy security, and environmental integrity. SNL works in partnerships with universities and industry to enhance their mission and transfer technology that will address emerging national challenges for both government and industry. For several years, the U.S. Department of Energy (DOE) Albuquerque Operations Office (AL) and New Mexico State University (NMSU) have maintained an inter-industry, input-output (I/O) model with capabilities to assess the impacts of developments initiated outside the economy such as federal DOE monies that flow into the state, on an economy. This model will be used to assess economic, personal income and employment impacts of SNL on Central New Mexico and the State of New Mexico. Caution should be exercised when comparing economic impacts between fiscal years prior to this report. The I/O model was rebased for FY 1998. The fringe benefits coefficients have been updated for the FY 1996 and FY 1997 economic impacts analysis. Prior to FY 1993 two different I/O base models were used to estimate the impacts. New technical information was released by the Bureau of Economic Analysis (BEA), U.S. Department of Commerce in 1991 and in 1994 and was incorporated in FY 1991, FY 1993, and FY 1994 I/O models. Also in 1993, the state and local tax coefficients and expenditure patterns were updated from a 1986 study for the FY 1992 report. Further details about the input-output model can be found in ''The Economic Impact of the Department of Energy on the State of New Mexico--FY 1998'' report by Lansford, et al. (1999). For this report, the reference period is FY 1998 (October 1, 1997, through September 30, 1998) and includes two major

  15. Hydrology of the Estancia Basin, central New Mexico

    Science.gov (United States)

    White, R.R.

    1993-01-01

    The Estancia Basin of central New Mexico is a topographically closed basin that ranges in altitude from 6,000 feet to more than 10,000 feet above sea level. In the center of the basin a valley-fill aquifer of Quaternary age is as much as 400 feet thick. Limestone of the Madera Group of Pennsylvanian and Permian age crops out over most of the southwestern part of the basin. Large-scale ground-water withdrawals for irrigation began about 1950. Between 1950 and 1985, water levels declined 50 to 60 feet in a number of places. From 1985 to the present (1989), however, a small rise in water level has been measured in a number of wells; this rise can be attributed to decreased ground-water withdrawals resulting from a government crop- reduction program and also to several years of heavy winter snowfall. Continuous water-level recorders were placed on three wells from 1986 to 1988. Two of these wells showed short-term water-level changes characteristic of unconfined aquifers, whereas the other showed changes characteristic of confined aquifers. All three wells showed water-level changes caused by barometric-pressure changes. Six series of miscellaneous measurements and two gain-and-loss (seepage) studies were made in streams in the south- western part of the basin. These measurements showed an extreme variability in discharge under different climatic conditions. The specific conductance of water in much of the southwestern part of the basin ranges from 350 to 550 microsiemens per centimeter at 25 degrees Celsius. East of State Highway 41 in the area of the salt lakes, water quality is highly dependent on depth in the aquifer. Specific- conductance values ranging from about 4,000 to 6,000 microsiemens were measured in water samples from wells in the center of the basin during this study, but previous studies have identified water samples having specific-conductance values of as much as 187,000 microsiemens. A comparison of specific- conductance measurements and laboratory

  16. Age of the Xalnene Ash, Central Mexico and Archeological Implications

    Science.gov (United States)

    Renne, P. R.; Feinberg, J. M.; Waters, M. R.; Cabrales, J. A.; Castillo, P. O.; Campa, M. P.; Knight, K. B.

    2005-12-01

    Human footprints ~40 ka old have been reported from the Toloquilla quarry near Valsequillo Reservoir, ca. 15 km south of the city of Puebla in central Mexico (http://www.mexicanfootprints.co.uk/default.htm). If correct, this would be important evidence for early peopling of the Americas. The indentations interpreted as footprints and other ichnofossils occur on the surface of an indurated basaltic lapilli tuff within a several meter thick sequence of thinly bedded (1-10 cm) tuffs of similar character, lacking paleosols, erosional features or interlayered sediments, informally known as the Xalnene ash. A sample was collected at 18°55.402` N latitude and 098°09.375` W longitude from the surface on which the purported footprints occur. Lapilli were separated and analyzed by incremental heating 40Ar/39Ar methods, yielding 9 indistinguishable plateau ages averaging 1.30 ±0.03 Ma (2σ) for single lapilli (N=6) and multiple lapilli (N=3) subsamples. Though some minor discordance (presumably due to 39Ar recoil) is manifest in 5 of the age spectra, all plateaux comprise >60% of the 39Ar released and 4 or more consecutive steps. Paleomagnetic data from azimuthally unoriented bulk samples of 11.25 cm3 reveal a reverse polarity (I = -32.1°) thermoremanent component carried by titanomagnetite and a normal polarity component carried by goethite. Measurements on individual matrix-free lapilli lack the goethite component, which is presumed to be associated with the clay-rich cement. Consistency of the reverse component implies deposition of the lapilli at supra-Curie temperatures, with no postdepositional reworking. Reverse polarity is consistent with deposition during chron C1r.2r (1.77 to 1.07 Ma) as indicated by the 40Ar/39Ar data. If the features observed on the tuff are indeed footprints, their 1.3 Ma antiquity would be truly remarkable, predating by far any other evidence for human presence in the Americas and in fact predating the evolutionary emergence of Homo sapiens

  17. Tectonic and metallogenic model for northeast Asia

    Science.gov (United States)

    Parfenov, Leonid M.; Nokleberg, Warren J.; Berzin, Nikolai A.; Badarch, Gombosuren; Dril, Sergy I.; Gerel, Ochir; Goryachev, Nikolai A.; Khanchuk, Alexander I.; Kuz'min, Mikhail I.; Prokopiev, Andrei V.; Ratkin, Vladimir V.; Rodionov, Sergey M.; Scotese, Christopher R.; Shpikerman, Vladimir I.; Timofeev, Vladimir F.; Tomurtogoo, Onongin; Yan, Hongquan; Nokleberg, Warren J.

    2011-01-01

    This document describes the digital files in this report that contains a tectonic and metallogenic model for Northeast Asia. The report also contains background materials. This tectonic and metallogenic model and other materials on this report are derived from (1) an extensive USGS Professional Paper, 1765, on the metallogenesis and tectonics of Northeast Asia that is available on the Internet at http://pubs.usgs.gov/pp/1765/; and (2) the Russian Far East parts of an extensive USGS Professional Paper, 1697, on the metallogenesis and tectonics of the Russian Far East, Alaska, and the Canadian Cordillera that is available on the Internet at http://pubs.usgs.gov/pp/pp1697/. The major purpose of the tectonic and metallogenic model is to provide, in movie format, a colorful summary of the complex geology, tectonics, and metallogenesis of the region. To accomplish this goal four steps were taken: (1) 13 time-stage diagrams, from the late Neoproterozoic (850 Ma) through the present (0 Ma), were adapted, generalized, and transformed into color static time-stage diagrams; (2) the 13 time-stage diagrams were placed in a computer morphing program to produce the model; (3) the model was examined and each diagram was successively adapted to preceding and subsequent diagrams to match the size and surface expression of major geologic units; and (4) the final version of the model was produced in successive iterations of steps 2 and 3. The tectonic and metallogenic model and associated materials in this report are derived from a project on the major mineral deposits, metallogenesis, and tectonics of the Northeast Asia and from a preceding project on the metallogenesis and tectonics of the Russian Far East, Alaska, and the Canadian Cordillera. Both projects provide critical information on bedrock geology and geophysics, tectonics, major metalliferous mineral resources, metallogenic patterns, and crustal origin and evolution of mineralizing systems for this region. The major

  18. Mexico’s Central American Policy: Apologies, Motivations, and Principles.

    Science.gov (United States)

    1982-03-15

    The carrots encompass developmental programs including road construction, medical clinics , new governmental stores, and agricultural extension...de las potencias medianas regionales-Ei caso de Mexico," Discussion Paper, Friedrich Ebert Stiftung, Bonn, West Germany, March 11, 1981, p. 8. 2. Ibid

  19. Archaeomagnetism of some pre-Columbian mural paintings in Central Mexico

    Science.gov (United States)

    Gogichaishvili, A.; Soler, A.; Zanella, E.; Lanza, R.; Chiari, G.; Urrutia-Fucugauchi, J.

    2003-12-01

    This work investigates the magnetic remanence associated with the mural paintings at three archeological sites in Central Mexico dated between 200 AD and 1450 AD (Cholula, Cacaxtla and Templo Mayor). The remanence of the murals is shown, using X-ray analyses and rock-magnetic measurements, to be carried by both magnetite and hematite. In most specimens, a characteristic magnetization is successfully isolated by alternating field demagnetization. The mean site directions are consistent with the available master curve for Mesoamerica. This work shows that murals from Central Mexico can retain their remanent magnetization for centuries and demonstrates the viability in principle of pictorial remanence as an archeomagnetic tool.

  20. A study of air flow patterns affecting pollutant concentrations in the Central Region of Mexico

    Science.gov (United States)

    Jazcilevich, Aron D.; García, Agustín. R.; Ruíz-Suárez, L. Gerardo

    Using a prognostic air quality model that includes actual emissions, air pollution regimes over the central region of Mexico are simulated. It is shown that due to the complex orography, vertical circular patterns develop over the metropolitan area of Mexico City. In this way reactive and non-reactive pollutants can travel near the surface, be transported vertically and land in an area opposite to its initial route due to convective downward currents. This changes the surface pollutant concentrations on the landing area. Also, it is shown that air pollution is transported near the surface from the metropolitan area of Mexico City through Chalco in the South-east corner of the Mexico Valley, to the Valley of Cuautla affecting this area.

  1. 78 FR 52562 - Outer Continental Shelf (OCS), Gulf of Mexico (GOM), Oil and Gas Lease Sales, Central Planning...

    Science.gov (United States)

    2013-08-23

    ... Bureau of Ocean Energy Management Outer Continental Shelf (OCS), Gulf of Mexico (GOM), Oil and Gas Lease Sales, Central Planning Area (CPA) Lease Sales 235, 241, and 247 AGENCY: Bureau of Ocean Energy... EIS for proposed Central Planning Area (CPA) Lease Sales 235, 241 and 247 in the Gulf of Mexico...

  2. METALLOGENIC SYSTEM OF DACHANG TINPOLYMETALLIC ORE FIELD

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-bin; DAI Ta-gen; WANG Zhi-bin; FANG Sheng-kui

    2001-01-01

    The Dachang tin-polymetallic ore field in northern Guangxi,China,lies in a mid-late Paleozoic rift that borders up the southern boundary of the Jiangnan-Xuefeng Massif.As a giant ore deposit,it deposited in middle of the Nandang-Hechi metallogenic zone.The orehosting strata are of the Devonion,which shows the evident characteristics of polymetallic elements,i.e: ,Sn,Zn,Pb,Sb,As,Cu,Ag,In,Ge,Cd,et al.,and over 1 000 000 t tin reserves.

  3. Mexico.

    Science.gov (United States)

    Semaan, Leslie

    The text explores Mexico's history, geography, art, religion, and lifestyles in the context of its complex economy. The text focuses on Mexico's economy and reasons for its current situation. Part I of this teaching unit includes: Teacher Overview, Why Study Mexico, Mexico Fact Sheet, Map of Mexico, the Land and Climate, History, Government,…

  4. Earthworm activity and soil structural changes under conservation agriculture in central Mexico

    NARCIS (Netherlands)

    Castellanos Navarrete, A.; Rodriguez-Aragonés, C.; Goede, de R.G.M.; Kooistra, M.J.; Sayre, K.D.; Brussaard, L.; Pulleman, M.M.

    2012-01-01

    Crop residue mulching combined with zero tillage and crop rotation, known as conservation agriculture (CA), is being promoted as an alternative system to revert soil degradation in maize-based farming in the central highlands of Mexico. The goal of this paper was to determine the effects of CA vs. c

  5. A rock- and paleomagnetic study of a Holocene lava flow in Central Mexico

    NARCIS (Netherlands)

    Vlag, P.; Alva-Valdivia, L.; Boer, C.B. de; Gonzalez, S.; Urrutia-Fucugauchi, J.

    2002-01-01

    Magnetic measurements of the Tres Cruces lava flow (ca. 8500 years BP, Central Mexico) show the presence of two remanence carriers, a Ti-rich titanomagnetite with a Curie temperature between 350 and 400 °C and a Ti-poor magnetite with a Curie temperature close to 580°C. Magnetic changes after heatin

  6. Teacher Socialization of EFL Teachers at Public School Levels in Central Mexico

    Science.gov (United States)

    Lengeling, M. Martha; Mora Pablo, Irasema; Barrios Gasca, Blanca Lucía

    2017-01-01

    This study aimed at exploring the processes of teacher socialization and identity formation of nine English as a foreign language teachers at public schools in central Mexico. These teachers began their careers in the National English Program in Basic Education. Qualitative research and narrative inquiry were used as a basis for this research. The…

  7. An Inventory of Natural, Human, and Social Overhead Capital Resources in North-Central New Mexico.

    Science.gov (United States)

    Carruthers, Garrey; Eastman, Clyde

    Concerned with the north-central area of New Mexico (Rio Arriba, Taos, Colfax, Mora, Santa Fe, and San Miguel counties), this inventory describes the situation and delineation of the region, the natural resources (physical characteristics, land, land-ownership patterns, land-use patterns, land-title problems, water resources, and minerals); human…

  8. Atmospheric chemistry effects of the 1998 Mexican/Central American fires measured in central New Mexico USA.

    Energy Technology Data Exchange (ETDEWEB)

    Popp, C. J.

    1998-12-16

    Atmospheric effects from large fires have received a great deal of interest recently, especially when the fires have the potential to effect human health when the plumes are transported long distances over areas of high population density. Examples are the recent large fires in Southeast Asia in 1997 (1) and the wildfires occurring in southern Mexico and Central America that were manifested in decreased visibility and high aerosol concentrations in the United States at distances of 2500-4000 km from the fires. In addition to fine aerosols, these biomass fires have the potential to produce and transport large quantities of oxygenated organic species such as aldehydes, ketones and carboxylic acids, hydrocarbons, and sulfate and nitrate species. Most of the literature reports dealing with products of biomass burning have been related to fireplace and wood burning stove emissions (2,3) and with local effects from forest fires(4). The recent super-large fires occurring in Indonesia and Mexico/Central America also bring about the issue of atmospheric reactivity because long-range transport affords long reaction times for photochemical reactions, wet and dry deposition and surface reactions on the aerosol particles. The smoke/haze conditions prompted considerable concern among the general population in New Mexico regarding health hazards and a large number of calls to the Albuquerque, NM Air Quality Division which reported the PM{sub 10} samples collected showed no significant increase in mass(5). The conclusion was that the particles were very fine and therefore had considerable influence on the visibility but did not violate health standards. In this study, organic and inorganic chemical species in the gaseous and aerosol phases have been identified and quantified under non-smoky and smoky conditions in Central New Mexico approximately 3000 km from the source of the fires.

  9. Contexts of offerings and ritual maize in the pictographic record in Central Mexico

    Directory of Open Access Journals (Sweden)

    Natalia Moragas Segura

    2015-01-01

    Full Text Available The objective of this article is an initial enquiry into the evidence and classification of the offerings of maize in Central Mexico from the Classic period to early colonial times. In order to achieve this goal, we will analyse the presence of maize in Central Mexico according to the evidence found in mural paintings and some pictographic codices. Two Mesoamerican cultures will be considered to achieve our analysis: the Teotihuacan and Mexico-Tenochtitlan. Maize was instrumental in the performance of daily rituals and in the diet of these ancient Mesoamerican cultures and the cereal also had sacred connotations in pre-Hispanic, colonial and contemporary narratives. We suggest this by reading the iconographic and symbolic representations of corn in the form of seeds and pods, or as an ingredient in cooked foods which are represented in the mural paintings of Teotihuacan as well as some codices of the post-Classic Nahua tradition. These methodological enquiries reveal evidence of a cultural continuity in Central Mexico as a contrasting perspective on the archaeological and ethno-historical period.

  10. Discrimination Study on Fluid—Rock Interaction Between Metallogenic and Non—Metallogenic Sections in a Shear Zone

    Institute of Scientific and Technical Information of China (English)

    魏俊浩; 李建威; 等

    1999-01-01

    Discriminations in a local chemical,fluidal,mechanical and thermal processes in a shear zone will lead to metallogenic differentiation in a local section.This paper,based on the general geological setting of the Shibangou gold deposit in Xixia,Henan,deals with petrological and petrochemical samples of altered rocks in the metallogenic section and of mylonites in the non-metallogenic section of a selected shear zone.The discriminations in fluid-rock interaction and petrological mass balance between altered rocks near the orebody and mylonites in the shear zone are discussed as well.The results show that the petrological volume of altered rocks in the metallogenic section of the shear zone is almost always dilatant and the mylonite volume in the non-metallogenic section is almost always lost.Major elements in altered rocks from the metallogenic section and in mylonites from the non-metallogenic section always show a tendency of being enriched and depleted,respectively.Fluid-rock ratios in the mylonites(Nu=93.68-468.40)are larger than those of the altered rocks(NC(Ⅳ)s=36.11-216.67).The gain and loss of major and trace elements from the altered rocks and mylonites in the shear zone are a composite process to be imported and exported by percolating fluids as well as of the loss and dilatancy of rock volume.

  11. Extensive diversity of Trypanosoma cruzi discrete typing units circulating in Triatoma dimidiata from central Veracruz, Mexico.

    Science.gov (United States)

    Ramos-Ligonio, Angel; Torres-Montero, Jesús; López-Monteon, Aracely; Dumonteil, Eric

    2012-10-01

    Chagas disease (or American trypanosomiasis) is a parasitic disease of major public health importance, caused by Trypanosoma cruzi, which presents extensive genetic diversity. The parasite has been classified into six lineages or discrete typing units (TcI to TcVI) and we performed here the molecular characterization of the strains present in Triatoma dimidiata, the main vector in central Veracruz, Mexico. Unexpectedly, TcI only represented 9/33 strains identified (27%), and we reported for the first time the presence of TcII, TcIII, TcIV and TcV strains in Mexico, at a relatively high frequency (13-27% each). Our observations indicate a much greater diversity of T. cruzi DTUs than previously estimated in at least part of Mexico. These results have important implications for the understanding of the phylogeography of T. cruzi DTUs and the epidemiology of Chagas disease in North America.

  12. Drug Cartels and Gangs in Mexico and Central America: A View through the Lens of Counterinsurgency

    Science.gov (United States)

    2010-06-04

    South America to the U.S.. Since Spanish colonization in the early sixteenth century, Central America and Mexico have endured civil wars, political...fundamental knowledge of the cultural and revolutionary events that shaped socio–political terrain in the region. From as early as the days of the Mayan ...empire, violence and conflict marked the Mesoamerican landscape. The Mayans , a conquering nation in their own right, imposed their rule of law on

  13. Water Quality of a Reservoir and Its Major Tributary Located in East-Central Mexico

    OpenAIRE

    2014-01-01

    A reservoir with ecological and economic importance and its major tributary, localized in east-central Mexico, were studied. The aim of this work was to know the physicochemical water characteristics of both water bodies and to contrast these by their different uses, and also estimate overall water quality using a Water Quality Index (WQI). Water samples from the reservoir and the tributary were obtained in different climatic seasons. In the tributary, anoxic and hypoxic conditions and high l...

  14. Teacher Socialization of EFL Teachers at Public School Levels in Central Mexico

    OpenAIRE

    M. Martha Lengeling; Irasema Mora Pablo; Blanca Lucía Barrios Gasca

    2017-01-01

    This study aimed at exploring the processes of teacher socialization and identity formation of nine English as a foreign language teachers at public schools in central Mexico. These teachers began their careers in the National English Program in Basic Education. Qualitative research and narrative inquiry were used as a basis for this research. The data revealed that the teachers’ socialization was somewhat informal in that little was required from them to gain entrance into the program. Once ...

  15. Cultures at the Crossroads: Art, Religion, and Interregional Interaction in Central Mexico, AD 600-900

    OpenAIRE

    Turner, Andrew

    2015-01-01

    Several competing centers emerged in Central Mexico around AD 600, including Cacaxtla, Xochicalco, and Teotenango. Monumental artwork at these sites appears to proclaim affiliation with distant regions of Mesoamerica, including the Gulf Coast, Oaxaca, and the Maya Lowlands. During the relatively brief florescence of these cities, they combined imagery and religious symbolism in novel ways that set the stage for patterns of interaction and modes of visual representation of later epochs. Howeve...

  16. Depositional environments of Late Triassic lake, east-central New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hester, P.M. (Bureau of Land Management, Albuquerque, NM (USA))

    1989-09-01

    The Redonda Member of the Chinle Formation represents deposition in a large, polymictic lake during the Late Triassic (Norian) in east-central New Mexico. This study documents and defines an extensive lacustrine system situated in western Pangaea which was influenced by both tectonic and climatic events. Areal extent of the lake may have been as much as 5,000 km{sup 2}.

  17. Ethnoecology of the palm Brahea dulcis (Kunth) Mart. in central Mexico

    OpenAIRE

    2015-01-01

    Background There have been few studies on the sustainable use of non-timber forest products in arid and semi-arid zones. The palm Brahea dulcis has been one of the most important resources in semi-arid Mesoamerica, since pre-Hispanic times. Currently, some populations grow within protected natural areas, representing both a challenge and an opportunity for local development. This ethnoecological study of B. dulcis in central Mexico aimed to evaluate their uses, harvesting context, and potenti...

  18. Toward a Unified Theory of Silent Seismicity in Central Mexico

    Science.gov (United States)

    Cruz-Atienza, V. M.; Rivet, D. N.; Kostoglodov, V.; Husker, A. L.; Legrand, D.; Campillo, M.

    2011-12-01

    During the 2006 slow slip event (SSE) in Guerrero, Mexico, a seismic profile was deployed above the slipping interface. Data from this seismological network generated several observations, including the detection of an ultra-slow velocity layer confined to the uppermost part of the slab (Song et al., Science, 2009), high Poisson's and Vp/Vs ratios within a large slab segment (Kim et al., JGR, 2010), and a transient reduction of surface waves velocity in the middle crust of about 0.2% due to the quasi-static slow-slip process (Rivet et al., GRL, 2011). Based on these observations, we have proceeded as follow. The slip history of the 2006 Guerrero SSE (Radiguet et al., GJI, 2010) was put into a 3D viscoelastic finite difference code, approximating the pore pressure as Pp=B*Pc, where B is the Skempton coefficient (0≤B≤1) and Pc is the confining pressure. Solving the fluid diffusion equation in the model, we find that the silent earthquake induces a widespread decrease of effective pressure, Pe=Pc-Pp (i.e. dilation increase), above the horizontal segment of the plate interface, where the NVT activity has been localized by previous authors (Payero et al., GRL, 2008; Husker et al., submitted, 2011). Assuming a fluid seal along the plate interface as suggested in Cascadia (Audet et al., Nature, 2009), the time-dependent migration (velocity) of confined fluids in the ultra-slow layer is first upward everywhere and then reorganizes by pointing two 'attraction' poles (i.e. low-pressure slab segments), the first one 80-90 km and the second one around 150 km away from the coast. We present NVT relocations obtained with a new and promising technique (Cruz-Atienza et al., in preparation, 2011). This technique is based on NVT energy-like and waveform correlation measurements in the three ground motion components. By superimposing the hypocentral relocations over the evolving Pp lithospheric cross-section, a surprisingly good correlation appears between the slab 'attraction

  19. soil carbon pools within oak forest is endangered by global climate change in central mexico

    Science.gov (United States)

    García-Oliva, Felipe; Merino, Agustín; González-Rodriguez, Antonio; Chávez-Vergara, Bruno; Tapia-Torres, Yunuen; Oyama, Ken

    2016-04-01

    Forest soil represents the main C pool in terrestrial ecosystems. In particular, temperate forest ecosystems play an important role in the C budget among tropical countries, such as Mexico. For example, the temperate forest ecosystem contains higher C contents on average (295 Mg C ha-1) than the soil C associated with other ecosystems in Mexico (between 56 to 287 Mg C ha-1). At a regional scale, oak forest has the highest C content (460 Mg C ha-1) among the forest ecosystem in Michoacán State at Central Mexico. At the local scale, the soil C content is strongly affected by the composition of organic matter produced by the plant species. The oak species are very diverse in Mexico, distributed within two sections: Quercus sensu stricto and Lobatae. The oak species from Quercus s.s. section produced litterfall with lower concentrations of recalcitrant and thermostable compounds than oak species from Lobatae section, therefore the soil under the former species had higher microbial activity and nutrient availability than the soil under the later species. However, the forest fragment with higher amount of oak species from Quercus s.s. section increases the amount of soil C contents. Unfortunately, Quercus species distribution models for the central western region of Mexico predict a decrease of distribution area of the majority of oak species by the year 2080, as a consequence of higher temperatures and lower precipitation expected under climate change scenarios. Additionally to these scenarios, the remnant oak forest fragments suffer strong degradation due to uncontrolled wood extraction and deforestation. For this reason, the conservation of oak forest fragments is a priority to mitigate the greenhouse gases emission to the atmosphere. In order to enhance the protection of these forest fragments it is required that the society identify the ecosystem services that are provided by these forest fragments.

  20. A review of ozone-induced effects on the forests of central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Maria de Lourdes de [Instituto de Recursos Naturales, Colegio de Postgraduados, Carretera Los Reyes-Texcoco, 56230 Montecillo, Edo. Mexico (Mexico)]. E-mail: libauer@colpos.mx; Hernandez-Tejeda, Tomas [Instituto Nacional de Investigaciones Forestales Agricolas y Pecuarias, Mexico, Col. Viveros de Coyoacan, 04110 Mexico, D.F. (Mexico)

    2007-06-15

    The first report on oxidant-induced plant damage in the Valley of Mexico was presented over 30 years ago. Ozone is known to occur in the Mexico City Metropolitan Area and elsewhere as the cause of chlorotic mottling on pine needles that are 2 years old or older as observed in 1976 on Pinus hartwegii and Pinus leiophylla. Visible evidences for the negative effects of ozone on the vegetation of central Mexico include foliar injury expressed as chlorotic mottling and premature defoliation on pines, a general decline of sacred fir, visible symptoms on native forest broadleaved species (e.g. Mexican black cherry). Recent investigations have also indicated that indirect effects are occurring such as limited root colonization by symbiotic fungi on ozone-damaged P. hartwegii trees and a negative influence of the pollutant on the natural regeneration of this species. The negative ozone-induced effects on the vegetation will most likely continue to increase. - Ozone induced symptoms, poor tree regeneration and limited root colonization by mycorrhiza fungi observed in the valley of Mexico.

  1. Socio-economic vulnerability to climate change in the central mountainous region of eastern Mexico.

    Science.gov (United States)

    Esperón-Rodríguez, Manuel; Bonifacio-Bautista, Martín; Barradas, Víctor L

    2016-03-01

    Climate change effects are expected to be more severe for some segments of society than others. In Mexico, climate variability associated with climate change has important socio-economic and environmental impacts. From the central mountainous region of eastern Veracruz, Mexico, we analyzed data of total annual precipitation and mean annual temperature from 26 meteorological stations (1922-2008) and from General Circulation Models. We developed climate change scenarios based on the observed trends with projections to 2025, 2050, 2075, and 2100, finding considerable local climate changes with reductions in precipitation of over 700 mm and increases in temperature of ~9°C for the year 2100. Deforested areas located at windward were considered more vulnerable, representing potential risk for natural environments, local communities, and the main crops cultivated (sugarcane, coffee, and corn). Socio-economic vulnerability is exacerbated in areas where temperature increases and precipitation decreases.

  2. The impact of religiosity on suicidal ideation among youth in central Mexico.

    Science.gov (United States)

    Hoffman, Steven; Marsiglia, Flavio F

    2014-02-01

    Although over 100 years of research has been dedicated to understanding the connection between religiosity and suicide, many questions still remain. This is especially true among adolescent populations in countries outside the US. In 2008, over 700 students attending eight alternative high school centers in central Mexico completed a health survey designed to provide a comprehensive overview of their physical, mental, spiritual, and emotional health. This article reports on the findings of a secondary analysis study of those data and focuses on the protective influence of religiosity on suicidal ideation. The findings of this study are discussed in light of the network theory's assertion that there is a belonging aspect to religion, and also to the idea that in religiously homogeneous communities of Mexico, religion can have a protective effect on the suicidal ideation of its members.

  3. Subsidence and associated shallow faulting hazard assessment in central Mexico using InSAR and GPS

    Science.gov (United States)

    Cabral-Cano, E.; Solano Rojas, D. E.; Oliver-Cabrera, T.; Salazar-Tlaczani, L.; Wdowinski, S.; DeMets, C.; Pacheco, J.

    2014-12-01

    While subsidence has affected Mexico City for over a century, other cities in central Mexico have been subjected to subsidence since the '80, as a result of their large urban expansion, population increase and aggressive groundwater extraction rates. The continuous subsidence results in severe damage to urban infrastructure and civil structures. Unfortunately the damage cost assessment and vulnerability are difficult to evaluate, because of the variable geographic extent and the continuous nature of the process, which have different characteristics than localized, short duration hazards, as earthquakes or flood events.We have monitored land subsidence in 17 cities in central Mexico using both InSAR and GPS observations. InSAR provides an unsurpassed synoptic view of the earth's dynamic surface. However, different satellite sensors and sometimes widely spaced data availability make it difficult to derive long-term time series, rapid changes or nonlinear variations of subsidence velocities. To alleviate this situation, higher temporal resolution subsidence observations of associated fault motion has been pursued using continuously operating GPS stations. We have developed a GPS network that covers 6 urban centers to detect short duration variations using different processing schemes that include both real-time solutions using RTNet as well as daily solution using Gipsy-Oasis.Cartographic products based on these techniques have been merged with other population, hydrology and meteorology data sets. This approach allows a better hazard assessment and provides information for other purposes, such as vulnerability for shallow faulting, land use zonations, and other decision elements for water resource management agencies. We will provide examples of these hazard assessments for several cities, including Mexico City, Aguascalientes, Morelia, Irapuato and Celaya and the challenges encountered to integrate these results with other data sets from federal and state

  4. Atmospheric particles in the central coastal zone of the Gulf of Mexico, Laguna Verde area, Veracruz, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Salazar L, S.; Alvarez D, C.; Mendoza M, R.; Perez A, J. A. [Laboratorio de Ingenieria Ambiental, Central Nucleoelectrica Laguna Verde, Comision Federal de Electricidad, Veracruz (Mexico); Castellanos R, M. A; Gomez L, B. [Departamento de Quimica Analitica, Laboratorio de Rayos X, Facultad de Quimica, UNAM, Mexico, D.F. (Mexico)

    1997-01-01

    The results of mass concentration of atmospheric particles collected by low volume samplers in sixteen monitoring stations of the Environmental Radiological Monitoring Network from Laguna Verde Nucleoelectric Plant, in Mexico, from 1991 to 1993, are reported. The levels of the yearly average mass concentrations were in a range of 22.6 {mu}g/m{sup 3} {+-} 5.0 {mu}g/m{sup 3} to 107.8 {mu}g/m{sup 3} {+-} 3.7 {mu}g/m{sup 3}. This variability is explained through the location of the stations, anthropogenic and natural influences. There were no significant differences in the average concentration over time. Moreover, the preliminary results of the chemical composition obtained by X Ray Fluorescence analysis are presented. [Spanish] Se presentan los resultados de la concentracion por peso de las particulas atmosfericas recolectadas con muestreadores de bajos volumenes en 16 estaciones de la Red del Monitoreo Radiologico Ambiental de la Central Nucleoelectrica Laguna Verde, en Mexico, durante el periodo 1991 a 1993. Los niveles de concentracion por peso de las particulas varian en un rango de promedios anuales de 22.6 {mu}g/m{sup 3} {+-} 5.0 {mu}g/m{sup 3} a 107.8 {mu}g/m{sup 3} {+-} 3.7 {mu}g/m{sup 3}. Esta variabilidad es explicada por la ubicacion de las estaciones, y las influencias naturales y antropogenicas. No fue observada variabilidad significativa en las concentraciones promedio a lo largo del tiempo. Se presentan los primeros resultados de la caracterizacion quimica del aerosol costero obtenido por medio de Fluorescencia de Rayos X.

  5. Teacher Socialization of EFL Teachers at Public School Levels in Central Mexico

    Directory of Open Access Journals (Sweden)

    M. Martha Lengeling

    2017-01-01

    Full Text Available This study aimed at exploring the processes of teacher socialization and identity formation of nine English as a foreign language teachers at public schools in central Mexico. These teachers began their careers in the National English Program in Basic Education. Qualitative research and narrative inquiry were used as a basis for this research. The data revealed that the teachers’ socialization was somewhat informal in that little was required from them to gain entrance into the program. Once teaching, the participants dealt with challenges in their teaching contexts and the program. From these challenges, the teachers were able to make decisions concerning their future as teachers, forming and imagining their identity.

  6. Fluoride in ash leachates: environmental implications at Popocatépetl volcano, central Mexico

    Directory of Open Access Journals (Sweden)

    M. A. Armienta

    2011-07-01

    Full Text Available Ash emitted by volcanic eruptions, even of moderate magnitude, may affect the environment and the health of humans and animals through different mechanisms at distances significantly larger than those indicated in the volcanic hazard maps. One such mechanism is the high capacity of ash to transport toxic volatiles like fluoride, as soluble condensates on the particles' surface. The mobilization and hazards related to volcanic fluoride are discussed based on the data obtained during the recent activity of Popocatépetl volcano in Central Mexico.

  7. CO2 Total Column Variability From Ground-Based FTIR Measurements Over Central Mexico

    Science.gov (United States)

    Baylon, J. L.; Stremme, W.; Plaza, E.; Bezanilla, A.; Grutter, M.; Hase, F.; Blumenstock, T.

    2014-12-01

    There are now several space missions dedicated to measure greenhouse gases in order to improve the understanding of the carbon cycle. Ground based measurement sites are of great value in the validation process, however there are only a few stations in tropical latitudes. We present measurements of solar-absorption infrared spectra recorded on two locations over Central Mexico: the High-Altitude Station Altzomoni (19.12 N, 98.65 W), located in the Izta-Popo National Park outside of Mexico City; and the UNAM's Atmospheric Observatory (19.32 N, 99.17 W) in Mexico City. These measurements were performed using a high resolution Fourier transform infrared spectrometer FTIR (Bruker, HR 120/5) at Altzomoni and a moderate resolution FTIR (Bruker, Vertex 80) within the city. In this work, we present the first results for total vertical columns of CO2 derived from near-infrared spectra recorded at both locations using the retrieval code PROFFIT. We present the seasonal cycle and variability from the measurements, as well as the full diagnostics of the retrieval in order assess its quality and discuss the differences of both instruments and locations (altitudes, urban vs remote). This work aims to contribute to generate high quality datasets for satellite validation.

  8. Contextualizing the trauma experience of women immigrants from Central America, South America, and Mexico.

    Science.gov (United States)

    Kaltman, Stacey; Hurtado de Mendoza, Alejandra; Gonzales, Felisa A; Serrano, Adriana; Guarnaccia, Peter J

    2011-12-01

    Trauma has been understudied among Latina immigrants from Central and South America. This study examined the types and context of trauma exposure experienced by immigrant women from Central America, South America, and Mexico living in the United States. Twenty-eight women seeking care in primary care or social service settings completed life history interviews. The majority of the women reported some type of trauma exposure in their countries of origin, during immigration, and/or in the United States. In the interviews, we identified types of trauma important to the experience of these immigrants that are not queried by trauma assessments typically used in the United States. We also identified factors that are likely to amplify the impact of trauma exposure. The study highlights the importance of utilizing a contextualized approach when assessing trauma exposure among immigrant women.

  9. Microsystems technologist workforce development capacity and challenges in Central New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Osborn, Thor D.

    2008-04-01

    Sandia National Laboratories has made major investments in microsystems-related infrastructure and research staff development over the past two decades, culminating most recently in the MESA project. These investment decisions have been made based in part upon the necessity for highly reliable, secure, and for some purposes, radiation-hardened devices and subsystems for safety and sustainability of the United States nuclear arsenal and other national security applications. SNL's microsystems development and fabrication capabilities are located almost entirely within its New Mexico site, rendering their effectiveness somewhat dependent on the depth and breadth of the local microsystems workforce. Consequently, the status and development capacity of this workforce has been seen as a key personnel readiness issue in relation to the maintenance of SNL's microsystems capabilities. For this reason SNL has supported the instantiation and development of the Southwest Center for Microsystems Education, an Advanced Technology Education center funded primarily by the National Science Foundation, in order to foster the development of local training capacity for microsystems technologists. Although the SCME and the associated Manufacturing Technology program at Central New Mexico Community College have developed an effective curriculum and graduated several highly capable microsystems technologists, the future of both the center and the degree program remain uncertain due to insufficient student enrollment. The central region of New Mexico has become home to many microsystems-oriented commercial firms. As the demands of those firms for technologists evolve, SNL may face staffing problems in the future, especially if local training capacity is lost.

  10. Neospora caninum infection in beef cattle reared under grazing conditions in north-central Mexico

    Directory of Open Access Journals (Sweden)

    Karina Mondragón-Zavala

    2011-05-01

    Full Text Available Objetive. To determine the seroprevalence of N. caninum antibodies and prevalence of parasite DNA in blood, and estimate the association between seroprevalence and the potential risk of some factors in beef cattle under grazing conditions in north-central Mexico. Materials and methods. Blood samples from 139 cows and only 10 bulls belonging to 13 farms were collected and evaluated by ELISA test to detect antibodies against N. caninum. Furthermore, to determine the presence of parasite DNA, nested PCR probe was performed on blood samples. Association between potential risk factors and seroprevalence was estimated. Results. Overall seroprevalence was 23% (35/149 samples, while the prevalence of parasite DNA in blood was 28% (42/149 samples. Of the 149 animals examined 28 (19% were positive to both tests (25 cows and 3 bulls. Concordance between tests was k = 0.63. All herds had seropositive animals with positive parasite DNA detection in blood. The only risk factor identified was the presence of dogs (OR= 2.65. Conclusions. This study showed that bovine neospososis should be considered as an important infectious disease in north-central Mexico herds. Therefore, an epidemiological control should be taken into consideration to avoid the negative effect of this disease on mexican beef industry.

  11. Teacher perceptions of the Centers for Ocean Sciences Education Excellence: Central Gulf of Mexico program

    Science.gov (United States)

    Sempier, Tracie Tingle

    The 12 Centers for Ocean Sciences Education Excellence (COSEE) are funded by the National Science Foundation and are designed to promote creative ways of disseminating marine science research and its importance to the public. The focus of this study is the COSEE Central Gulf of Mexico program which encourages active partnerships between research scientists and teachers. In these collaborative partnerships, teachers and scientists work together to create educational products and disseminate best practices in ocean sciences education. The purpose of this study was to determine whether the lesson plans and curricula created through the Centers for Ocean Sciences Education Excellence: Central Gulf of Mexico program (COSEE:CGOM), which are the products of this collaboration, were being used effectively in the classroom. The study addressed issues such as teacher perceptions of collaboration with scientists, effectiveness of COSEE:CGOM curriculum implementation in producing more ocean literate students, and teachers' varying views concerning how to successfully implement new COSEE:CGOM knowledge and concepts into their classrooms in order to improve student scientific understanding. In addition, the study examined frequency of use of COSEE:CGOM lesson plans and identified predictor variables that can produce a model for understanding factors hindering or enhancing lesson plan use. Further, participant perceptions of using peer-teaching as a method for disseminating COSEE:CGOM information in their districts were addressed.

  12. Geoid modeling in Mexico and the collaboration with Central America and the Caribbean.

    Science.gov (United States)

    Avalos, D.; Gomez, R.

    2012-12-01

    The model of geoidal heights for Mexico, named GGM10, is presented as a geodetic tool to support vertical positioning in the context of regional height system unification. It is a purely gravimetric solution computed by the Stokes-Helmert technique in resolution of 2.5 arc minutes. This product from the Instituto Nacional de Estadistica y Geografia (INEGI) is released together with a series of 10 gravimetric models which add to the improvements in description of the gravity field. In the recent years, the INEGI joined the initiative of the U.S. National Geodetic Survey and the Canada's Geodetic Survey Division to promote the regional height system unification. In an effort to further improve the compatibility among national geoid models in the region, the INEGI has begun to champion a network of specialists that includes national representatives from Central America and the Caribbean. Through the opening of opportunities for training and more direct access to international agreements and discussions, the tropical region is gaining participation. Now a significantly increased number of countries is pushing for a future North and Central American geoid-based vertical datum as support of height system unification.eoidal height in Mexico, mapped from the model GGM10.

  13. Mexico.

    Science.gov (United States)

    1988-02-01

    Focus in this discussion of Mexico is on the following: geography; the people; history; political conditions; the economy; foreign relations; and relations between the US and Mexico. As of July 1987, the population of Mexico numbered 81.9 million with an estimated annual growth rate of 2.09%. 60% of the population is Indian-Spanish (mestizo), 30% American Indian, 9% white, and 1% other. Mexico is the most populous Spanish-speaking country in the world and the 2nd most populous country in Latin America. Education is decentralized and expanded. Mexico's topography ranges from low desert plains and jungle-like coastal strips to high plateaus and rugged mountains. Hernan Cortes conquered Mexico in 1919-21 and founded a Spanish colony that lasted for almost 300 years. Independence from Spain was proclaimed by Father Miguel Hidalgo on September 16, 1810; the republic was established on December 6, 1822. Mexico's constitution of 1917 provides for a federal republic with a separation of powers into independent executive, legislative, and judicial branches of government. Significant political themes of the administration of President Miguel de la Madrid Hurtado, who began his 6-year term in 1982, have been restructuring the economy, liberalizing trade practices, decentralizing government services, and eliminating corruption among public servants. In 1987, estimates put the real growth of the Mexican economy at 1.5%; the gross domestic product (GDP) had shrunk by 3.5% in 1986. Yet, on the positive side, Mexico's international reserves increased to record levels in 1987 (to about $15 billion), and its current account surplus reached more than $3 billion. Mexico has made considerable progress in moving to restructure its economy. It has substantially reduced impediments to international trade and has moved to reduce the number of parastatal firms. 1987 was the 2nd consecutive year in which Mexico recorded triple-digit inflation; inflation reached 158.8%. Other problems include

  14. Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign

    Directory of Open Access Journals (Sweden)

    P. F. DeCarlo

    2008-07-01

    Full Text Available The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1 was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA and biomass burning (BB are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m−3 (STP ppm−1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006 and Kleinman et al. (2008. The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance

  15. Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign

    Science.gov (United States)

    Decarlo, P. F.; Dunlea, E. J.; Kimmel, J. R.; Aiken, A. C.; Sueper, D.; Crounse, J.; Wennberg, P. O.; Emmons, L.; Shinozuka, Y.; Clarke, A.; Zhou, J.; Tomlinson, J.; Collins, D. R.; Knapp, D.; Weinheimer, A. J.; Montzka, D. D.; Campos, T.; Jimenez, J. L.

    2008-07-01

    The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m-3 (STP) ppm-1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to

  16. Metallogenic Series Related to Permian Mafic Complex in North Xinjiang: Post-collisional Stage or Mantle Plume Result?

    Institute of Scientific and Technical Information of China (English)

    WANG Yuwang; WANG Jingbin; WANG Lijuan; LONG Lingli

    2008-01-01

    There are four deposit types related to a Permian mafic complex in northern Xinjiang, i.e.,copper-nickel sulfide deposit, vanadic titanomagnetite deposit, magnetite (-cobalt) deposit and Cu-Ni-VTiFe composite deposit. The deposits are distributed spanning tectonic units with dose andconsecutive metallogenic ages. A transitional deposit type can occur among the end-member deposits.Trace elements of host rocks show that they can derive from similar source area. Hence, theyconstitute a particular metallogenic series related to a mafic-ultramafic complex that is also a symbolseries of the post-collisional stage of the Central Asia Metallogenic Province (CAMP). Themetallogenic ages of the series are between 260 Ma and 300 Ma throughout the Permian. Unlikemineralization from a mantle plume, the metallogenic period of this series spans at least 40 Ma.Compared with related deposits of the Emeishan mantle plume, the North Xinjiang series has asimilar ore-forming element assemblage but has preferably developed Cu-Ni sulfide deposits ratherthan vanadic titanomagnetite deposits. In concomitance with this series, North Xinjiang area hasdeveloped a set of syntectonic Au-Cu-Mo metailogenic series related to a felsic volcanic-intrusivecomplex, which might indicate that there is no direct relationship with mantle plume activity. Fromearly to late, i.e., the sequence of copper-nickel sulfide to magnetite (-cobalt) to vanadictitanomagnetite deposit, the host rock series evolves from mafic-ultramafic and tholeiite series tomafic and alkalic series, the ∑REE content tends to increase with increasing of REE fractionation, andsome of the trace elements (particularly LIL) also show an increasing tendency. The aboveevolutionary regularity possibly reflects a course where the magma source deepens and thermalinterface moves down, energy gradually exhausts, and neo-continentai crust forming in the post-collision stage tends to stabilize.

  17. Satellite Remote Sensing Analysis to Monitor Desertification Processes in Central Plateau of Mexico

    Science.gov (United States)

    Becerril, R.; González Sosa, E.; Diaz-Delgado, C.; Mastachi-Loza, C. A.; Hernández-Tellez, M.

    2013-05-01

    Desertification is defined as land degradation in arid, semi-arid and sub-humid areas due to climatic variations and human activities. Therefore there is a need to monitor the desertification process in the spatiotemporal scale in order to develop strategies to fight against desertification (Wu and Ci, 2002). In this sense, data provided by remote sensing is an important source for spatial and temporal information, which allows monitoring changes in the environment at low cost and high effectiveness. In Mexico, drylands hold 65% of the area, with about 1,280,494 km2 (UNESCO, 2010), where is located 46% of the national population (SEMARNAT, 2008). Given these facts, there is interest in monitoring the degradation of these lands, especially in Mexico because no specific studies have identified trends and progress of desertification in the country so far. However, it has been considered land degradation as an indicator of desertification process. Thus, it has been determined that 42% of soils in Mexico present some degradation degree. The aim of this study was to evaluate the spatial and temporal dynamics of desertification for 1993, 2000 and 2011 in the semiarid central plateau in Mexico based on demographic, climatic and satellite data. It took into consideration: 1) the Anthropogenic Impact Index (HII), based on the spatial population distribution and its influence on the use of resources and 2) the Aridity Index (AI), calculated with meteorological station records for annual rainfall and potential evapotranspiration. Mosaics were made with Landsat TM scenes; considering they are a data source that allows evaluate surface processes regionally and with high spectral resolution. With satellite information five indices were estimated to assess the vegetation and soil conditions: Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), Weighted Difference Vegetation Index (WDVI), Grain Size Index (GSI) and Bare Soil Index (BSI). The rates

  18. Emerging deforestation trends in tropical dry forests ecoregions of Mexico and Central America

    Science.gov (United States)

    Portillo, C. A.; Cao, G.; Smith, V.

    2015-12-01

    Neotropical dry forests (TDF) have experienced an unprecedented deforestation that is leading to the loss of tropical biodiversity at a rapid pace, but information on deforestation dynamics in TDF is scarce. In this study, we present a sub-continental and national level assessment of TDF loss patterns in Mexico and Central America at high spatial and temporal resolution using remote sensing and GIS technologies. We used the Global Forest Change (GFC) dataset published by Hansen et al. (2013) which shows results from time-series analysis of Landsat images in characterizing global forest extent and change from 2000 through 2013. We analyzed forest loss within and around mapped TDF cover mapped by Portillo-Quintero et al. 2010. In order to minimize errors in source data, we overlaid a 25 x 25 km grid on top of the regional dataset and conducted a cell by cell and country by country inspection at multiple scales using high resolution ancillary data. We identified trends in the clustering of space-time TDF deforestation data using ArcGIS, categorizing trends in: new, consecutive, intensifying, persistent, diminishing, sporadic, oscillating and historical hotspots (high frequency of deforestation events) and cold spots (low frequency of deforestation). In general, the region is experiencing less frequent deforestation events with a higher number of intensifying and new cold spots across TDF landscapes. However, an important number of intensifying and persistent hotspots exist so no general trend in forest loss was detected for the period 2001-2013, except for El Salvador which shows a significant decreasing trend in forest loss. Mexico, Nicaragua, Honduras and Guatemala are the major sources of intensifying, persistent and new deforestation hot spots. These were identified in the southern pacific coast and the Yucatan Peninsula in Mexico, northwestern Guatemala, both western and eastern Honduras and around Lake Nicaragua in Nicaragua.

  19. The Irish potato famine pathogen Phytophthora infestans originated in central Mexico rather than the Andes.

    Science.gov (United States)

    Goss, Erica M; Tabima, Javier F; Cooke, David E L; Restrepo, Silvia; Fry, William E; Forbes, Gregory A; Fieland, Valerie J; Cardenas, Martha; Grünwald, Niklaus J

    2014-06-17

    Phytophthora infestans is a destructive plant pathogen best known for causing the disease that triggered the Irish potato famine and remains the most costly potato pathogen to manage worldwide. Identification of P. infestan's elusive center of origin is critical to understanding the mechanisms of repeated global emergence of this pathogen. There are two competing theories, placing the origin in either South America or in central Mexico, both of which are centers of diversity of Solanum host plants. To test these competing hypotheses, we conducted detailed phylogeographic and approximate Bayesian computation analyses, which are suitable approaches to unraveling complex demographic histories. Our analyses used microsatellite markers and sequences of four nuclear genes sampled from populations in the Andes, Mexico, and elsewhere. To infer the ancestral state, we included the closest known relatives Phytophthora phaseoli, Phytophthora mirabilis, and Phytophthora ipomoeae, as well as the interspecific hybrid Phytophthora andina. We did not find support for an Andean origin of P. infestans; rather, the sequence data suggest a Mexican origin. Our findings support the hypothesis that populations found in the Andes are descendants of the Mexican populations and reconcile previous findings of ancestral variation in the Andes. Although centers of origin are well documented as centers of evolution and diversity for numerous crop plants, the number of plant pathogens with a known geographic origin are limited. This work has important implications for our understanding of the coevolution of hosts and pathogens, as well as the harnessing of plant disease resistance to manage late blight.

  20. Cooperation and tensions in multiethnic corporate societies using Teotihuacan, Central Mexico, as a case study.

    Science.gov (United States)

    Manzanilla, Linda R

    2015-07-28

    In this paper, I address the case of a corporate society in Central Mexico. After volcanic eruptions triggered population displacements in the southern Basin of Mexico during the first and fourth centuries A.D., Teotihuacan became a multiethnic settlement. Groups from different backgrounds settled primarily on the periphery of the metropolis; nevertheless, around the core, intermediate elites actively fostered the movement of sumptuary goods and the arrival of workers from diverse homelands for a range of specialized tasks. Some of these skilled craftsmen acquired status and perhaps economic power as a result of the dynamic competition among neighborhoods to display the most lavish sumptuary goods, as well as to manufacture specific symbols of identity that distinguished one neighborhood from another, such as elaborate garments and headdresses. Cotton attire worn by the Teotihuacan elite may have been one of the goods that granted economic importance to neighborhood centers such as Teopancazco, a compound that displayed strong ties to the Gulf Coast where cotton cloth was made. The ruling elite controlled raw materials that came from afar whereas the intermediate elite may have been more active in providing other sumptuary goods: pigments, cosmetics, slate, greenstone, travertine, and foreign pottery. The contrast between the corporate organization at the base and top of Teotihuacan society and the exclusionary organization of the neighborhoods headed by the highly competitive intermediate elite introduced tensions that set the stage for Teotihuacan's collapse.

  1. Human footprints in Central Mexico older than 40,000 years

    Science.gov (United States)

    González, Silvia; Huddart, David; Bennett, Matthew R.; González-Huesca, Alberto

    2006-02-01

    The timing, route and origin of the first colonization to the Americas remains one of the most contentious topics in human evolution. A number of migration routes have been suggested and there are different views as to the antiquity of the earliest human occupation. Some believe that settlement happened as early as 30 ka BP, but most of the currently accepted early sites in North America date to the latest Pleistocene, related to the expansion of the Clovis culture, while the oldest directly radiocarbon dated human remains are 11.5 ka BP. In this context new evidence is presented in this paper, in the form of human footprints preserved in indurated volcanic ash, to suggest that Central Mexico was inhabited as early as over 40 ka BP. Human and animal footprints have been found within the upper bedding surfaces of the Xalnene volcanic ash layer that outcrops in the Valsequillo Basin, south of Puebla, Mexico. This ash layer was produced by a subaqueous monogenetic volcano erupting within a palaeo-lake, dammed by lava within the Valsequillo Basin during the Pleistocene. The footprints were formed during low stands in lake level along the former shorelines and indicate the presence of humans, deer, canids, big felids, and probably camels and bovids. The footprints were buried by ash and lake sediments as lake levels rose and transgressed across the site. The ash has been dated to at least 40 ka BP by OSL dating of incorporated, baked lake sediments.

  2. Historical polycyclic aromatic and petrogenic hydrocarbon loading in Northern Central Gulf of Mexico shelf sediments

    Energy Technology Data Exchange (ETDEWEB)

    Overton, E.B.; Ashton, B.M.; Miles, M.S. [Louisiana State University, Baton Rouge, LA (United States). Dept. of Environmental Studies

    2005-10-01

    The distribution of selected hydrocarbons within ten dated sediment cores taken from the Mississippi River Bight off coastal Louisiana suggests a chronic contaminant loading from several sources including the river itself, oil and gas exploration in the central Gulf of Mexico (GOM) shelf area, and natural geologic hydrocarbon seeps. Data were grouped as either total polycyclic aromatic hydrocarbons (PAH's), which were indicative of pyrogenic PAH's; or estimated total hopanes (indicative of petrogenic hydrocarbons). The total PAH concentrations and estimated total hopanes begin increasing above background levels (approximately 200 ng g{sup -1}) after the 1950s. The distribution of these hydrocarbons and hopanes within the dated sediment cores suggests that the Mississippi River is a regional source of pyrogenic PAH's, and that the hopanes are from natural geologic hydrocarbon seeps, oil and gas exploration in the GOM, or both. (author)

  3. House infestation dynamics and feeding sources of Triatoma dimidiata in central Veracruz, Mexico.

    Science.gov (United States)

    Torres-Montero, Jesús; López-Monteon, Aracely; Dumonteil, Eric; Ramos-Ligonio, Angel

    2012-04-01

    Chagas disease is endemic in the state of Veracruz, Mexico, and we investigated here the dynamics of house infestation by Chagas disease vectors to understand disease transmission and design effective control interventions. Bug collections in 42 rural villages confirmed the widespread distribution of Triatoma dimidiata in central Veracruz. Unexpectedly, collection data further indicated a clear pattern of seasonal infestation by mostly adult bugs. Analysis of feeding sources with a polymerase chain reaction-heteroduplex assay indicated a frequent feeding on humans, in agreement with the high seroprevalence previously observed. Feeding sources also confirmed a significant dispersal of bugs between habitats. High dispersal capabilities and seasonal infestation may thus be a shared characteristic of several of the T. dimidiata sibling species from this complex. It would thus be critical to adapt vector control interventions to this behavior to improve their efficacy and sustainability, as the control of T. dimidiata has been notoriously challenging.

  4. Rock Magnetic Properties of a Late Pleistocene Paleosol From Central Mexico

    Science.gov (United States)

    Rivas, J.; Ortega, B.; Solleiro, E.; Sedov, S.

    2005-05-01

    Rock-magnetic characteristics of a volcaniclastic-paleosol sequence from Tlaxcala, central Mexico, are analyzed in order to test the hypothesis of neo-formation of magnetic minerals as result of enhanced pedogenesis in A and B soil horizons, in comparison of the less affected or pedoganically unaltered parent material. Our study was carried out in a Chromic luvisol pedocomplex thought to have been formed during the last interglacial. The results show that, even if pedogenic fine grained magnetic minerals are present in the Bt horizons, these are destroyed in upper horizons, where pedogenesis has been more intense. Horizons A and E present the lowest magnetic susceptibility, however they also present the highest concentration of high coercivity hematite/goethite phases. In order to decode the paleoclimatic signal of this paleosol, rock-magnetism analysis in different pedogenetic materials as the soil itself, and cutans, cracks-filling material and humus found in soils, is in progress.

  5. A detailed rock-magnetic and archeomagnetic study of lime-plasters from central Mexico

    Science.gov (United States)

    Soler-Arechalde, A. M.; Rodriguez, M.; Ramirez, O.; Gogichaishvili, A.; Caballero-Miranda, C.; Hueda-Tanabe, Y.; Urrutia-Fucugauchi, J.

    2003-04-01

    We carried out a reconnaissance rock-magnetic and archeomagnetic investigations of lime-plasters at some most important pre-Hispanic sites in Central Mexico. Both burned and unburned lime plasters (in total 30 samples) were analyzed from Teotihuacan, Tlatelolco, Santa Cruz Atizapan and Pañhu. The characteristic directions determined in this study are considered to be of primary origin. Thermomagnetic investigation show that the remanence is carried in most cases by magnetite or Ti-poor titanomagnetite. Unblocking temperature spectra and relatively high coercivity point to 'small' pseudo-single domain magnetic structure grains as responsible for remanent magnetization. Single-component, linear demagnetization plots were observed in most of cases. The mean site directions are consistent with the available reference master curve for Mesoamerica.

  6. Water-quality and ground-water-level data, Bernalillo County, central New Mexico, 1995

    Science.gov (United States)

    Rankin, D.R.

    1996-01-01

    Water-quality and ground-water-level data were collected in two areas of eastern Bernalillo County in central New Mexico between March and July of 1995. Fifty-one wells, two springs, and the Ojo Grande Acequia in the east mountain area of Bernalillo County and nine wells in the northeast area of the city of Albuquerque were sampled. The water samples were analyzed for selected nutrient species; total organic carbon; major dissolved constituents; dissolved arsenic, boron, iron, and manganese; and methylene blue active substances. Analytical results were used to compute hardness, sodium adsorption ratio, and dissolved solids. Specific conductance, pH, temperature, and alkalinity were measured in the field at the time of sample collection. Ground- water-level and well-depth measurements were made at the time of sample collection when possible. Water-quality data, ground- water-level data, and well-depth data are presented in tabular form.

  7. Land Management Strategies and their Implications for Mazahua Farmers’ Livelihoods in the Highlands of Central Mexico

    Directory of Open Access Journals (Sweden)

    García-Fajardo Belina

    2016-06-01

    Full Text Available This paper presents a case study from a Mazahua indigenous community in the rural Highlands of Central Mexico. It analyses Mazahua farming livelihoods characterised by subsistence agriculture, marginality, poverty and severe land degradation. Mazahua farmers face constrained environmental, socioeconomic and cultural conditions, which influence their local decisions on natural resource management. The results describe the capital assets base used, where land, livestock and crop production are imperative assets to support farmers’ livelihood strategies. It analyses local management practices to achieve livelihood outcomes in the short/long term, and to improve or undermine land characteristics and other related assets. It also presents a farmer typology constructed by local perceptions, a controversial element to drive sustainable development strategies at the local level. Finally, it discusses how local land management practices are adopted and their importance in developing alternatives to encourage positive trade-offs between conservation and production in order to improve rural livelihoods.

  8. The ectomycorrhizas of Lactarius cuspidoaurantiacus and Lactarius herrerae associated with Alnus acuminata in Central Mexico.

    Science.gov (United States)

    Montoya, Leticia; Bandala, Victor M; Garay-Serrano, Edith

    2015-08-01

    Two pure Alnus acuminata stands established in a montane forest in central Mexico (Puebla State) were monitored between 2010 and 2013 to confirm and recognize the ectomycorrhizal (EcM) systems of A. acuminata with Lactarius cuspidoaurantiacus and Lactarius herrerae, two recently described species. Through comparison of internal transcribed spacer (ITS) of nuclear ribosomal DNA sequences from basidiomes and ectomycorrhizas sampled in the forest stands, we confirmed their ectomycorrhizal association. The phytobiont was corroborated by comparing ITS sequences obtained from EcM root tips and leaves collected in the study site and from other sequences of A. acuminata available in Genbank. Detailed morphological and anatomical descriptions of the ectomycorrhizal systems are presented and complemented with photographs.

  9. Yanshanian Magma-Tectonic-Metallogenic Belt in East China of Circum-Pacific Domain (Ⅱ): Lithosphere-Asthenosphere System and Metallogenic Environment

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    This paper shows that the catastrophe of lithosphere-asthenosphere system (LAS) is developed for the Yanshanian metallogenic belt in the East China. Two types of Yanshanian disturbed LAS and metallogenesis in the East China are recognized: great lithosphere thinning and thickening in the compressional orogenic environment, and the related Andes-type and Hercyn-type metallogenesis,respectively. Great amount of the juvenile and hot mantle materials and the reactivated hot lower crustal materials replaced, heated and injected into the cold lithosphere and crust are believed to be a fundamental source and a basic deep environment for the Yanshanian metallogenic explosion. Reactivated and active discontinuities on the lithosphere scale are considered to be the main ore-storing space of the metallogenic zone. Large magma-tectonic-metallogenic system is necessary for the formation of large cluster area of ore deposit. The eastern China is believed to have large potential for prospecting of ore deposits in terms of the metallogenic environment.

  10. Late Quaternary vegetation history of Rough Canyon, south-central New Mexico, USA

    Science.gov (United States)

    Betancourt, J.L.; Aasen, Rylander K.; Penalba, C.; McVickar, J.L.

    2001-01-01

    South-central New Mexico, USA, at the junction of the Rocky Mountains, High Plains and Chihuahuan Desert, is one of the better known regions in the late Quaternary of North America. Plant macrofossils and pollen from a packrat midden series in Rough Canyon, New Mexico allows refinement of plant distributions and paleoclimates in this transitional area since full glacial times. From 17000 to 12000 14C yr BP, Pinus edulis-Juniperus scopulorum woodlands dominated limestone substrates between 1800 and 1490 m, with Pseudotsuga menziesii and other mixed-conifer species restricted to shady, north-facing slopes. Juniperus deppeana, the dominant juniper today above 2000 m in southern New Mexico, is conspicuously absent from glacial middens and must have been displaced south of the US-Mexico border. The minimum climatic conditions for P. edulis-J. scopulorum woodlands are ca 20% wetter and 3.5-5??C cooler (July mean maximum temperatures) than the modern climate at Rough Canyon. Holocene warming/drying may have started as early as 12000 14C yr BP with the extirpation of J. scopulorum from Rough Canyon, and was completed by at least 10540 14C yr BP. The record for arrivals of some desert species is confounded by traces of pollen and macrofossils in some of the glacial middens, which could signify either earliest occurrence or temporal mixing (contamination) of assemblages. AMS 14C dating can discriminate between early arrival and contamination in midden macrofossils but not in pollen. AMS dates show that Choisya dumosa, presently near its northern (cold) limits at Rough Canyon, endured late glacial winters, possibly as clonal populations. Some Larrea tridentata leaves and pollen occur in middens dominated by conifers and oaks no longer at the site; an AMS date of 3205 14C yr BP on Larrea leaves from one midden indicates contamination. Evidence for some macrofossil contamination, however, does not rule out the possibility that pollen of desert elements (e.g. Larrea, Prosopis

  11. Strategic integration of public transport networks with airport infrastructure in the megalopolis of Central Mexico: Evolution and challenges

    NARCIS (Netherlands)

    Salinas, C.R.; Garcia Cejudo, D.; Van Timmeren, A.

    2014-01-01

    Airports represent the contemporary global gateways of metropolitan areas worldwide. In the case of the megalopolis of Central Mexico, air transport was traditionally used only by upper social segments of the population, however, during the last years, the introduction of low-cost airlines in the co

  12. Formation, production and viability of oospores of Phytophthora infestans from potato and Solanum demissum in the Toluca Valley, central Mexico

    NARCIS (Netherlands)

    Flier, W.G.; Grünwald, N.J.; Fry, W.E.; Turkensteen, L.J.

    2001-01-01

    Aspects of the ecology of oospores of Phytophthora infestans were studied in the highlands of central Mexico. From an investigation of a random sample of strains, it was found that isolates differed in their average capability to form oospores when engaged in compatible pairings. Most crosses produc

  13. Phytophthora ipomoeae, a new homothallic species causing leaf blight on Ipomoea longipedunculata in the Toluca Valley of central Mexico

    NARCIS (Netherlands)

    Flier, W.G.; Grunwald, N.J.; Kroon, L.P.N.M.; Bosch, van den G.B.M.; Garay-Serrano, E.; Lozoya-Saldan, H.; Bonants, P.J.M.; Turkensteen, L.J.

    2002-01-01

    A Phytophthora species was found on blighted foliage of Ipomoea longipedunculata, a morning glory native to the highlands of central Mexico. Based on host range, morphology, allozymes, mitochondrial DNA haplotype and rDNA sequences it is concluded that a new Phytophthora species, P. ipomoeae sp. nov

  14. 77 FR 40081 - Gulf of Mexico, Outer Continental Shelf (OCS), Western Planning Area (WPA) and Central Planning...

    Science.gov (United States)

    2012-07-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management Gulf of Mexico, Outer Continental Shelf (OCS), Western Planning Area (WPA) and Central Planning Area (CPA), Oil and Gas Lease Sales for 2012-2017 AGENCY: Bureau of...

  15. Late Pleistocene-Holocene cataclysmic eruptions at Nevado de Toluca and Jocotitlan volcanoes, central Mexico

    Science.gov (United States)

    Macias, J.L.; Garcia, P.A.; Arce, J.L.; Siebe, C.; Espindola, J.M.; Komorowski, J.C.; Scott, K.

    1997-01-01

    This field guide describes a five day trip to examine deposits of Late Pleistocene-Holocene cataclysmic eruptions at Nevado de Toluca and Jocotitlan volcanoes in central Mexico. We will discuss the stratigraphy, petrology, and sedimentological characteristics of these deposits which provide insights into the eruptive history, type of volcanic activity, and transport and emplacement mechanisms of pyroclastic materials. These parameters will allow us to discuss the kinds of hazards and the risk that they pose to populations around these volcanoes. The area to be visited is tectonically complex thus we will also discuss the location of the volcanoes with respect to the tectonic environment. The first four days of the field trip will be dedicated to Nevado de Toluca Volcano (19 degrees 09'N; 99 degrees 45'W) located at 23 km. southwest of the City of Toluca, and is the fourth highest peak in the country, reaching an elevation of 4,680 meters above sea level (m.a.s.l.). Nevado de Toluca is an andesitic-dacitic stratovolcano, composed of a central vent excavated upon the remains of older craters destroyed by former events. Bloomfield and Valastro, (1974, 1977) concluded that the last cycle of activity occurred nearly equal 11,600 yr. ago. For this reason Nevado de Toluca has been considered an extinct volcano. Our studies, however, indicate that Nevado de Toluca has had at least two episodes of cone destruction by sector collapse as well as several explosive episodes including plinian eruptions and dome-destruction events. These eruptions occurred during the Pleistocene but a very young eruption characterized by surge and ash flows occurred ca. 3,300 yr. BP. This new knowledge of the volcano's eruptive history makes the evaluation of its present state of activity and the geological hazards necessary. This is important because the area is densely populated and large cities such as Toluca and Mexico are located in its proximity.

  16. Mexico Geoid Heights (MEXICO97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' geoid height grid for Mexico, and North-Central America, is the MEXICO97 geoid model. The computation used about one million terrestrial and marine gravity...

  17. The economic impact of Los Alamos National Laboratory on north-central New Mexico and the state of New Mexico fiscal year 1998

    Energy Technology Data Exchange (ETDEWEB)

    Lansford, R.R. [New Mexico State Univ., Las Cruces, NM (US); Adcock, L.D.; Gentry, L.M. [Albuquerque Operations Office, Dept. of Energy, Albuquerque, NM (US); Ben-David, S. [Univ. of New Mexico, Albuquerque, NM (US). Dept. of Economics; Temple, J. [Temple (John), Albuquerque, NM (US)

    1999-08-05

    Los Alamos National Laboratory (LANL) is a multidisciplinary, multiprogram laboratory with a mission to enhance national military and economic security through science and technology. Its mission is to reduce the nuclear danger through stewardship of the nation`s nuclear stockpile and through its nonproliferation and verification activities. An important secondary mission is to promote US industrial competitiveness by working with US companies in technology transfer and technology development partnerships. Los Alamos is involved in partnerships and collaborations with other federal agencies, with industry (including New Mexico businesses), and with universities worldwide. For this report, the reference period is FY 1998 (October 1, 1997, through September 30, 1998). It includes two major impact analysis: the impact of LANL activities on north-central New Mexico and the economic impacts of LANL on the state of New Mexico. Total impact represents both direct and indirect responding by business, including induced effects (responding by households). The standard multipliers used in determining impacts result from the inter-industry, input-output models developed for the three-county region and the state of New Mexico.

  18. Metallogenic Districts of Yangtze Cratonic Rim at the Edge of Chaos

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Combining the science of complexity with ore geology, the author puts forward a new theory of metallogenesis: "complexity and self-organized criticality of metallogenic dynamic systems", and three fundamental theories are raised for it. The ore genesis and regularity of ore formation of four metallogenic districts around the Yangtze craton in China are studied with this theory. It is found that"metallogenic districts of Yangtze cratonic rim are all at the edge of chaos". This proposition is expounded by four determinative criteria of the edge of chaos for metallogenic districts of Yangtze cratonic rim.

  19. Influence of supercontinent cyclicity on global metallogenic processes: Main tendencies

    Science.gov (United States)

    Tkachev, A. V.; Rundquist, D. V.

    2016-08-01

    The distribution of large and superlarge mineral deposits (LSMD) of the most important raw materials is correlated with supercontinent cycles in the geological history of the Earth. The latter displays the distinct correlation between metallogenic activity and cyclic global endogenous processes reflected in quasi-regular cycles, which result eventually in the assembly and breakup of supercontinents. In the framework of these cycles, the maximums in the LSMD assembly coincide with periods of intense growth of the subcontinent crust owing to growth of the matter originated from juvenile sources (Kenoran, Columbian cycles) or with epochs of intense recycling of the mature crust (Pangean, Amasian cycles). The Rodinian cycle with minimum activity of these both endogenous processes demonstrates simultaneously minimum metallogenic activity. The distribution of most LSMD types generally follows these main tendencies.

  20. Magnitude and extent of land subsidence in central Mexico revealed by regional InSAR ALOS time-series survey

    Science.gov (United States)

    Chaussard, E.; Wdowinski, S.; Amelung, F.; Cabral-Cano, E.

    2013-05-01

    Massive groundwater extraction is very common in Mexico and is well known to result in land subsidence. However, most surveys dedicated to land subsidence focus on one single city, mainly Mexico City, and thus fail to provide a comprehensive picture of the problem. Here we use a space-based radar remote sensing technique, known as Interferometric Synthetic Aperture Radar (InSAR) to detect land subsidence in the entire central Mexico area. We used data from the Japanese satellite ALOS, processed over 600 SAR images acquired between 2007-2011 and produced over 3000 interferograms to cover and area of 200,000 km2 in central Mexico. We identify land subsidence in twenty-one areas, including seventeen cities, namely from east to west, Puebla, Mexico city, Toluca de Lerdo, Queretaro, San Luis de la Paz, south of San Luis de la Paz, Celaya, south of Villa de Reyes, San Luis Potosi, west of Villa de Arista, Morelia, Salamanca, Irapuato, Silao, Leon, Aguascalientes, north of Aguascalientes, Zamora de Hidalgo, Guadalajara, Ahuacatlan, and Tepic. Subsidence rates of 30 cm/yr are observed in Mexico City, while in the other locations typical rates of 5-10 cm/yr are noticed. Regional surveys of this type are necessary for the development of hazard mitigation plans and efficient use of ground-based monitoring. We additionally correlate subsidence with land use, surface geology, and faults distribution and suggest that groundwater extraction for agricultural, urban, and industrial uses are the main causes of land subsidence. We also reveal that the limits of the subsiding areas often correlate with existing faults, motion on these faults being driven by water extraction rather than by tectonic activity. In all the subsiding locations we observe high ground velocity gradients emphasizing the significant risks associated with land subsidence in central Mexico. Averaged 2007-2011 ground velocity map from ALOS InSAR time-series in central Mexico, revealing land subsidence in 21

  1. The combined influence of Pacific decadal oscillation and Atlantic multidecadal oscillation on central Mexico since the early 1600s

    Science.gov (United States)

    Park, Jungjae; Byrne, Roger; Böhnel, Harald

    2017-04-01

    Periodic droughts have been one of the most serious environmental issues in central Mexico since the earliest times. The impacts of future droughts are likely to become even more severe as the current global warming trend increases potential evaporation and moisture deficits. A full understanding of the mechanism underlying climate variability is imperative to narrow the uncertainty about future droughts and predict water availability. The climatic complexity generated by the combined influence of both Atlantic and Pacific forcings, however, causes considerable difficulty in interpreting central Mexican climate records. Also, the lack of high-resolution information regarding the climate in the recent past makes it difficult to clearly understand current drought mechanisms. Our new high-resolution δ18 O record from Hoya Rincon de Parangueo in central Mexico provides useful information on climate variations since the early 1600s. According to our results, the central Mexican climate has been predominantly controlled by the combined influence of the 20-year Pacific Decadal Oscillation (PDO) and the 70-year Atlantic Multidecadal Oscillation (AMO). However, the AMO probably lost much of its influence in central Mexico in the early 20th century and the PDO has mostly driven climate change since. Marked dryness was mostly associated with co-occurrence of highly positive PDO and negative AMO between ∼1600 and 1900.

  2. Metallogenic belt and mineral deposit maps of northeast Asia

    Science.gov (United States)

    Obolenskiy, Alexander A.; Rodionov, Sergey M.; Dejidmaa, Gunchin; Gerel, Ochir; Hwang, Duk-Hwan; Miller, Robert J.; Nokleberg, Warren J.; Ogasawara, Masatsugu; Smelov, Alexander P.; Yan, Hongquan; Seminskiy, Zhan V.

    2013-01-01

    This report contains explanatory material and summary tables for lode mineral deposits and placer districts (Map A, sheet 1) and metallogenic belts of Northeast Asia (Maps B, C, and D on sheets 2, 3, and 4, respectively). The map region includes eastern Siberia, southeastern Russia, Mongolia, northeast China, and Japan. A large group of geologists—members of the joint international project, Major Mineral Deposits, Metallogenesis, and Tectonics of Northeast Asia—prepared the maps, tables, and introductory text. This is a cooperative project with the Russian Academy of Sciences, Mongolian Academy of Sciences, Mongolian National University, Ulaanbaatar, Mongolian Technical University, Mineral Resources Authority of Mongolia, Geological Research Institute, Jilin University, China Geological Survey, Korea Institute of Geoscience and Mineral Resources, Geological Survey of Japan, and U.S. Geological Survey. This report is one of a series of reports on the mineral resources, geodynamics, and metallogenesis of Northeast Asia. Companion studies include (1) a detailed geodynamics map of Northeast Asia (Parfenov and others, 2003); (2) a compilation of major mineral deposit models (Rodionov and Nokleberg, 2000; Rodionov and others, 2000); (3) a series of metallogenic belt maps (Obolenskiy and others, 2004); (4) location map of lode mineral deposits and placer districts of Northeast Asia (Ariunbileg and others, 2003b); (5) descriptions of metallogenic belts (Rodionov and others, 2004); (6) a database on significant metalliferous and selected nonmetalliferous lode deposits and selected placer districts (Ariunbileg and others, 2003a); and (7) a series of summary project publications (Ariunbileg and 74 others, 2003b).

  3. Geochemical and faunal investigation of shelf/slope environment of north-central Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Healy-Williams, N.; Trainor, D.M.; Williams, D.F.; Jenkins, P. (Univ. of South Carolina, Columbia (United States)); Gary, A. (Unocal, Brea, CA (United States))

    1991-03-01

    The shelf/slope environment of the northern Gulf of Mexico offers a complex pattern of marine and terrestrial derived sediments. The authors have performed geochemical and faunal investigations on approximately 80 box cores from 30 to 1,300 m water depth from the north-central Gulf of Mexico. The geochemical results relate the modern and late Holocene distribution of marine and terrestrial organic carbon to the present day depositional systems of this actively prograding system. Total organic carbon (%TOC) analyses of the surface sediment are used to characterize the distribution of TOC on the Louisiana shelf and slope as a function of distance from the Mississippi delta. Stable carbon isotopic analyses ({sup 13}C/{sup 12}C) of the TOC are used to distinguish marine from terrestrial organic carbon. Higher amounts of terrestrial organic carbon are associated with the western edge of the Mississippi delta. Marine organic carbon increases seaward of the deltaic system. The percentage of fine-grained (< 63 microns) calcium carbonate also increases seaward of the Mississippi delta as well as with lateral distance along the shelf-slope. Percent CaCO{sub 3} and {delta}{sup 13}C of the fine-grained carbonate determinations have been performed in Plio-Pleistocene cores and exploration wells from this region. The authors use this data to examine how the modern/late Holocene patterns of these variables have changed as a function of continental margin evolution. They have also analyzed the benthic foraminiferal distributions in terms of the sedimentary nature of the box cores. They note increased abundances in certain species in relation to deltaic vs nondeltaic environments along with some species altering their depth ranges between the two environments.

  4. Climate change in Central America and Mexico: regional climate model validation and climate change projections

    Energy Technology Data Exchange (ETDEWEB)

    Karmalkar, Ambarish V. [University of Oxford, School of Geography and the Environment, Oxford (United Kingdom); Bradley, Raymond S. [University of Massachusetts, Department of Geosciences, Amherst, MA (United States); Diaz, Henry F. [NOAA/ESRL/CIRES, Boulder, CO (United States)

    2011-08-15

    Central America has high biodiversity, it harbors high-value ecosystems and it's important to provide regional climate change information to assist in adaptation and mitigation work in the region. Here we study climate change projections for Central America and Mexico using a regional climate model. The model evaluation shows its success in simulating spatial and temporal variability of temperature and precipitation and also in capturing regional climate features such as the bimodal annual cycle of precipitation and the Caribbean low-level jet. A variety of climate regimes within the model domain are also better identified in the regional model simulation due to improved resolution of topographic features. Although, the model suffers from large precipitation biases, it shows improvements over the coarse-resolution driving model in simulating precipitation amounts. The model shows a dry bias in the wet season and a wet bias in the dry season suggesting that it's unable to capture the full range of precipitation variability. Projected warming under the A2 scenario is higher in the wet season than that in the dry season with the Yucatan Peninsula experiencing highest warming. A large reduction in precipitation in the wet season is projected for the region, whereas parts of Central America that receive a considerable amount of moisture in the form of orographic precipitation show significant decreases in precipitation in the dry season. Projected climatic changes can have detrimental impacts on biodiversity as they are spatially similar, but far greater in magnitude, than those observed during the El Nino events in recent decades that adversely affected species in the region. (orig.)

  5. Climate change in Central America and Mexico: regional climate model validation and climate change projections

    Science.gov (United States)

    Karmalkar, Ambarish V.; Bradley, Raymond S.; Diaz, Henry F.

    2011-08-01

    Central America has high biodiversity, it harbors high-value ecosystems and it's important to provide regional climate change information to assist in adaptation and mitigation work in the region. Here we study climate change projections for Central America and Mexico using a regional climate model. The model evaluation shows its success in simulating spatial and temporal variability of temperature and precipitation and also in capturing regional climate features such as the bimodal annual cycle of precipitation and the Caribbean low-level jet. A variety of climate regimes within the model domain are also better identified in the regional model simulation due to improved resolution of topographic features. Although, the model suffers from large precipitation biases, it shows improvements over the coarse-resolution driving model in simulating precipitation amounts. The model shows a dry bias in the wet season and a wet bias in the dry season suggesting that it's unable to capture the full range of precipitation variability. Projected warming under the A2 scenario is higher in the wet season than that in the dry season with the Yucatan Peninsula experiencing highest warming. A large reduction in precipitation in the wet season is projected for the region, whereas parts of Central America that receive a considerable amount of moisture in the form of orographic precipitation show significant decreases in precipitation in the dry season. Projected climatic changes can have detrimental impacts on biodiversity as they are spatially similar, but far greater in magnitude, than those observed during the El Niño events in recent decades that adversely affected species in the region.

  6. Geology and Geochronology of the Central Part of Chiapanecan Volcanic Arc, Mexico.

    Science.gov (United States)

    Layer, P. W.

    2006-12-01

    The Chiapanecan Volcanic Arc (CVA) is a 150 km stretch of volcanoes irregularly aligned in a northwest direction, including El Chichón volcano located in the central portion of the State of Chiapas, southern Mexico. It lies between two great volcanic features: the Trans-Mexican Volcanic Arc to the northwest, and the Central American Volcanic Arc to the southeast, in a complex zone of the interaction of the North American, Caribbean and Cocos Plates. The central part of the CVA is composed of an irregular northwest alignment of at least 12 volcanic structures located 80 km to the southeast of El Chichón (the only currently active volcano in the CVA). These structures include one explosion crater (Navenchauc), one collapse structure (Apas), one dome complex (Tzontehuitz) and nine volcanic domes (Navenchauc, Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza, Miguel Hidalgo and Santotón) with associated pyroclastic flow deposits. The juvenile lithics from these deposits have a porphyritic texture with phenocrysts of plagioclase (±), amphibole (±), clinopyroxene (±), orthopyroxene (±) and Fe-Ti oxides surrounded by a matrix composed by microlites of plagioclase and glass. The chemical results obtained from representative samples from the deposits and structures indicate that these belong to the series of subalkaline rocks, and fall into the calcalkaline field with medium to high contents of potassium. They vary in their composition from andesite to dacite with an interval of silica between a 56 to a 66% (wt.). The ages reported in the literature and obtained in this study by means of the K-Ar and the 40Ar/39Ar methods, respectively, indicated that volcanism was episodic and spanned a time from 2100 ky ago (Tzontehuitz) to 225 ky ago (Venustiano Carranza).

  7. Floods of November 1978 to March 1979 in Arizona and west-central New Mexico

    Science.gov (United States)

    Aldridge, Byron Neil; Hales, T.A.

    1984-01-01

    Severe flooding occurred in parts of the Little Colorado and Gila River basins as a result of a storm that occurred December 17-20, 1978. The central highlands received 3 to 10 inches of precipitation that was augmented by snowmelt to altitudes of 10,000 feet. The storm was preceded by extremely large amounts of rainfall and runoff in November and was followed by other periods of high runoff in January and March 1979. In some areas flood peaks in November, January, or March were higher than the peak of December 1978. At Winslow, the discharge of the Little Colorado River in December 1978 was the highest since at least 1952. The discharge of the Gila River above the San Francisco River was probably the highest since at least 1891, and in the Safford Valley, the peak was the highest since 1916. The Agua Fria River below Waddell Dam had the highest discharge since 1919. The flood of December 1978 caused 12 deaths and caused damage that was probably in excess of $150 million in Arizona and west-central New Mexico. Damage was estimated to be $51.8 million in Maricopa County, Arizona. Floods caused extensive agricultural damage along the Gila River in Virden Valley in New Mexico and in Duncan, York, and Safford Valleys in Arizona. Duncan, Arizona, was flooded with as much as 7 feet of water. The flood crest on the Gila River in December 1978 moved from Redrock, New Mexico, to Duncan, Arizona, in about 6 hours, which is more rapid than during other recent floods but is comparable to the travel-time recorded in 1941. Travel-time in the reach varies with discharge and is about 14 hours for discharges of 10,000 cubic feet per second and 5 hours for discharges of more than 40,000 cubic feet per second. Water-conservation reservoirs on the Gila, Salt, Verde, and Agua Fria Rivers and a flood-control reservoir on the Gila River had a major influence on the magnitude of floods downstream from the reservoirs. All runoff from the Gila River basin upstream from Coolidge Dam, Arizona

  8. Significance of detrital zircons in upper Devonian ocean-basin strata of the Sonora allochthon and Lower Permian synorogenic strata of the Mina Mexico foredeep, central Sonora, Mexico

    Science.gov (United States)

    Poole, F.G.; Gehrels, G.E.; Stewart, John H.

    2008-01-01

    U-Pb isotopic dating of detrital zircons from a conglomeratic barite sandstone in the Sonora allochthon and a calciclastic sandstone in the Mina Mexico foredeep of the Minas de Barita area reveals two main age groups in the Upper Devonian part of the Los Pozos Formation, 1.73-1.65 Ga and 1.44-1.42 Ga; and three main age groups in the Lower Permian part of the Mina Mexico Formation, 1.93-1.91 Ga, 1.45-1.42 Ga, and 1.1-1.0 Ga. Small numbers of zircons with ages of 2.72-2.65 Ga, 1.30-1.24 Ga, ca. 2.46 Ga, ca. 1.83 Ga, and ca. 0.53 Ga are also present in the Los Pozos sandstone. Detrital zircons ranging in age from 1.73 to 1.65 Ga are considered to have been derived from the Yavapai, Mojave, and Mazatzal Provinces and their transition zones of the southwestern United States and northwestern Mexico. The 1.45-1.30 Ga detrital zircons were probably derived from scattered granite bodies within the Mojave and Mazatzal basement rocks in the southwestern United States and northwestern Mexico, and possibly from the Southern and Eastern Granite-Rhyolite Provinces of the southern United States. The 1.24-1.0 Ga detrital zircons are believed to have been derived from the Grenville (Llano) Province to the east and northeast or from Grenvilleage intrusions or anatectites to the north. Several detrital zircon ages ranging from 2.72 to 1.91 Ga were probably derived originally from the Archean Wyoming Province and Early Paleoproterozoic rocks of the Lake Superior region. These older detrital zircons most likely have been recycled one or more times into the Paleozoic sandstones of central Sonora. The 0.53 Ga zircon is believed to have been derived from a Lower Cambrian granitoid or meta-morphic rock northeast of central Sonora, possibly in New Mexico and Colorado, or Oklahoma. Detrital zircon geochronology suggests that most of the detritus in both samples was derived from Laurentia to the north, whereas some detritus in the Permian synorogenic foredeep sequence was derived from the

  9. Stratigraphy and Facies Analysis of a 122 M Long Lacustrine Sequence from Chalco Lake, Central Mexico

    Science.gov (United States)

    Herrera, D. A.; Ortega, B.; Caballero, M.; Lozano, S.; Pi, T.; Brown, E. T.

    2010-12-01

    Chalco lake is located SE of the outskirts of Mexico City, at the central part of the Trans Mexican Volcanic Belt. Previous studies show the importance of this lacustrine sequence as an archive of paleoenvironmental and paleoclimatic changes. A set of five cores up to 122 m depth were drilled in the basin, in order to analyze the sedimentary record and to extent the previous knowledge of past environmental changes in central Mexico. As an initial step, in this work we present the identification and classification of sedimentary facies. Preliminary paleomagnetism analyses recognize the possible record of the Blake Event (ca. 120 kyr BP), and suggest that the sequence might span the last 240 kyr. In this case, variations in sedimentary facies could reflect the conditions of the MIS 1-7. The facies are mostly diatom ooze, carbonate mud, organic rich silt and volcaniclastic, both massive and laminated, and massive dark gray to reddish brown silt. From 1 to 8 m depth dominates the organic rich silt facies, which correlates with the MIS 1. Intercalations of reddish brown and grayish brown silt facies, between 8 to 60 m depth, indicate changes occurred during MIS 2 to 5d. Between 60-75 m depth the sequence is characterized by dark grayish silty clay facies, which possibly coincide with the MIS 5e. At 79 m depth (ca. 130 kyr BP) we found struvite (MgNH4PO4.6H2O), which may be related to dry conditions. The laminated diatom ooze facies dominates between 90 to 122 m depth and indicates rhythmic changes in the sediment deposition of the basin. The volcaniclastic facies is represented by lapilli and ash deposits in more than 100 individual tephra layers of both mafic and felsic composition. Some of them correspond to main volcanic eruptions, as the Upper Toluca Pumice (13,500 cal yr BP), from the Nevado de Toluca volcano and the Pómez con Andesita (17,700 cal yr BP) from the Popocatépetl volcano. The carbonate mud facies is composed of calcite and siderite, with frequent

  10. Water balances of old-growth and regenerating montane cloud forests in central Veracruz, Mexico

    Science.gov (United States)

    Muñoz-Villers, L. E.; Holwerda, F.; Gómez-Cárdenas, M.; Equihua, M.; Asbjornsen, H.; Bruijnzeel, L. A.; Marín-Castro, B. E.; Tobón, C.

    2012-09-01

    SummaryThis paper compares the water budgets of two adjacent micro-catchments covered by mature (MAT) and 20-year-old secondary (SEC) lower montane cloud forests, respectively, in central Veracruz, Mexico over a 2-year period. Rainfall (P) and streamflow (Q) were measured continuously, whereas dry canopy evaporation (transpiration Et), wet canopy evaporation (rainfall interception I), and cloud water interception (CWI) were quantified using a combination of field measurements and modeling. Mean annual P was 3467 mm, of which typically 80% fell during the wet season (May-October). Fog interception occurred exclusively during the dry season (November-April), and was ⩽2% of annual P for both forests. Rainfall interception loss was dominated by post-event evaporation of intercepted water rather than by within-event evaporation. Therefore, the higher overall I (i.e. including CWI) by the MAT (16% of P vs. 8% for the SEC) reflects a higher canopy storage capacity, related in turn to higher leaf area index and greater epiphyte biomass. Annual Et totals derived from sapflow measurements were nearly equal for the MAT and SEC (˜790 mm each). Total annual water yield calculated as P minus (Et + I) was somewhat higher for the SEC (2441 mm) than for the MAT (2077 mm), and mainly reflects the difference in I. Mean annual Q was also higher for the SEC (1527 mm) than for the MAT (1338 mm), and consisted mostly of baseflow (˜90%). Baseflow recession rates were nearly equal between the two forests, as were stormflow coefficients (4% and 5% for MAT and SEC, respectively). The very low runoff response to rainfall is attributed to the high infiltration and water retention capacities of the volcanic soils throughout the ˜2 m deep profile. The water budget results indicate that ˜875 and 700 mm year-1 leave the SEC and MAT as deep groundwater leakage, which is considered plausible given the fractured geology in the study area. It is concluded that 20 years of natural regeneration

  11. Recent Intermediate Depth Earthquakes in El Salvador, Central Mexico, Cascadia and South-West Japan

    Science.gov (United States)

    Lemoine, A.; Gardi, A.; Gutscher, M.; Madariaga, R.

    2001-12-01

    We studied occurence and source parameters of several recent intermediate depth earthquakes. We concentrated on the Mw=7.7 salvadorian earthquake which took place on January 13, 2001. It was a good example of the high seismic risk associated to such kind of events which occur closer to the coast than the interplate thrust events. The Salvadorian earthquake was an intermediate depth downdip extensional event which occured inside the downgoing Cocos plate, next to the downdip flexure where the dip increases sharply before the slab sinks more steeply. This location corresponds closely to the position of the Mw=5.7 1996 and Mw=7.3 1982 downdip extensional events. Several recent intermediate depth earthquakes occured in subduction zones exhibiting a ``flat slab'' geometry with three distinct flexural bends where flexural stress may be enhanced. The Mw=6.7 Geiyo event showed a downdip extensional mechanism with N-S striking nodal planes. This trend was highly oblique to the trench (Nankai Trough), yet consistent with westward steepening at the SW lateral termination of the SW Japan flat slab. The Mw=6.8 Olympia earthquake in the Cascadia subduction zone occured at the downdip termination of the Juan de Fuca slab, where plate dip increases from about 5o to over 30o. The N-S orientation of the focal planes, parallel to the trench indicated downdip extension. The location at the downdip flexure corresponds closely to the estimated positions of the 1949 M7.1 Olympia and 1965 M6.5 Seattle-Tacoma events. Between 1994 and 1999, in Central Mexico, an unusually high intermediate depth seismicity occured where several authors proposed a flat geometry for the Cocos plate. Seven events of magnitude between Mw=5.9 and Mw=7.1 occured. Three of them were downdip compressional and four where down-dip extensional. We can explain these earthquakes by flexural stresses at down-dip and lateral terminations of the supposed flat segment. Even if intermediate depth earthquakes occurence could

  12. Cenozoic evolution of tectono-fluid and metallogenic process in Lanping Basin,western Yunnan Province, Southwest China: Constraints from apatite fission track data

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoming; SONG Yougui

    2006-01-01

    Since the Mesozoic, abundant metal and salt deposits have been formed in the Lanping Basin, western Yunnan Province, Southwest China, constituting a well-known hydrothermal ore belt in China. Most of the deposits are meso-epithermal hydrothermal deposits. This paper preliminarily deals with the mineralization ages of hydrothermal deposits in the Lanping Basin by using the apatite fission track method, and integrates the spatial distribution of the deposits and their regional geological backgrounds, to give the preliminary viewpoints as follows: (1) the apatite fission track ages acquired range from 19.9 Ma to 52.8 Ma, much younger than those of their host strata, so they may be considered to be mineralization ages, which represent the late mineralization period; (2) the apatite fission track ages tend to become younger from the west to the middle of the basin, indicating that the latest evolution of tectono-fluid and/or metallogenic processes of the middle basin ended later than that in the west; (3) in the Paleogene, most of the Cu deposits were formed in the western part of the basin; (4) the major metallogenic processes occur between the Paleogene and the Neogene, because the eastern and western edges of the basin were subducted into and collided with its bilateral continental blocks, respectively, and the central fault was strongly activated, which led to the processes of large-scale ore-forming fluids, and their differentiation and transport because of the variation of their physical and chemical properties. Having been squeezed and uplifted, the Lanping Basin became an intermontane basin that contains many kinds of fluid traps resulting in the formation of different types of ore deposits (for example, Pb-Zn, Cu, Ag) of different scales in the middle of the basin. Simultaneously, the fluids with volatile elements such as Hg, Sb and As were transported upwards along the central fault system and diffused into its subordinate fractures, thus leading to the

  13. [Nesting habitat characterization for Amazona oratrix (Psittaciformes: Psittacidae) in the Central Pacific, Mexico].

    Science.gov (United States)

    Monterrubio-Rico, Tiberio C; Álvarez-Jara, Margarito; Tellez-Garcia, Loreno; Tena-Morelos, Carlos

    2014-09-01

    The nesting requirements of the Yellow-headed Parrot (Amazona oratrix) are poorly understood, despite their broad historical distribution, high demand for pet trade and current endangered status. Information concerning their nesting requirements is required in order to design specific restoration and conser- vation actions. To assess this, we studied their nesting ecology in the Central Pacific, Michoacan, Mexico during a ten year period. The analyzed variables ranged from local scale nest site characteristics such as nesting tree species, dimensions, geographic positions, diet and nesting forest patches structure, to large scale features such as vegetation use and climatic variables associated to the nesting tree distributions by an ecological niche model using Maxent. We also evaluated the parrot tolerance to land management regimes, and compared the Pacific nest trees with 18 nest trees recorded in an intensively managed private ranch in Tamaulipas, Gulf of Mexico. Parrots nested in tall trees with canopy level cavities in 92 nest-trees recorded from 11 tree species. The 72.8% of nesting occurred in trees of Astronium graveolens, and Enterolobium cyclocarpum which qualified as key- stone trees. The forests where the parrots nested, presented a maximum of 54 tree species, 50% of which were identified as food source; besides, these areas also had a high abundance of trees used as food supply. The lowest number of tree species and trees to forage occurred in an active cattle ranch, whereas the highest species rich- ness was observed in areas with natural recovery. The nesting cavity entrance height from above ground of the Pacific nesting trees resulted higher than those found in the Gulf of Mexico. We hypothesize that the differences may be attributed to Parrot behavioral differences adapting to differential poaching pressure and cavity avail- ability. Nesting trees were found in six vegetation types; however the parrots preferred conserved and riparian semi

  14. Extinction Risk of Pseudotsuga Menziesii Populations in the Central Region of Mexico: An AHP Analysis

    Directory of Open Access Journals (Sweden)

    Javier López-Upton

    2015-05-01

    Full Text Available Within the Analytic Hierarchy Process (AHP framework, a hierarchical model was created considering anthropogenic, genetic and ecological criteria and sub-criteria that directly affect Douglas-fir (Pseudotsuga menziesii (Mirb. risk of extinction in central Mexico. The sub-criteria values were standardized, weighted, and ordered by importance in a pairwise comparison matrix; the model was mathematically integrated to quantify the degree of extinction risk for each of the 29 populations present in the study area. The results indicate diverse levels of risk for the populations, ranging from very low to very high. Estanzuela, Presa Jaramillo, Peñas Cargadas and Plan del Baile populations have very low risk, with values less than 0.25. On the other hand, Vicente Guerrero, Morán, Minatitlán, La Garita and Tonalapa populations have very high risk (>0.35 because they are heavily influenced by anthropogenic (close to roads and towns, ecological (presence of exotic species and little or no natural regeneration and genetic (presence of mature to overmature trees and geographic isolation factors. In situ conservation activities, prioritizing their implementation in populations at most risk is highly recommended; in addition, germplasm collection for use of assisted gene flow and migration approaches, including artificial reforestation, should be considered in these locations.

  15. The influence of mistletoes on birds in an agricultural landscape of central Mexico

    Science.gov (United States)

    Zuria, Iriana; Castellanos, Ignacio; Gates, J. Edward

    2014-11-01

    Mistletoes are hemiparasitic flowering plants that function as keystone resources in forests and woodlands of temperate regions, where a positive relationship between mistletoe density and avian species richness has been observed. Mistletoes have been less studied in tropical regions and the relationship between birds and mistletoes has seldom been explored in tropical agricultural systems. Therefore, we studied the presence of infected trees and infection prevalence (i.e., number of parasitized trees/total number of trees) by Psittacanthus (Loranthaceae) mistletoes in 23 hedgerows located in an agricultural landscape of central Mexico during the dry and rainy seasons, and investigated the relationship between bird species richness and abundance and the abundance of mistletoes. We found a mean of 74 mistletoe plants per 100-m transect of only one species, Psittacanthus calyculatus. Thirty-one percent of the trees surveyed were infected and tree species differed in infection prevalence, mesquite (Prosopis laevigata) being the most infected species with 86% of the surveyed trees infected. For both seasons, we found a positive and significant association between bird species richness and number of mistletoe plants. The same pattern was observed for total bird abundance. Many resident and Neotropical migratory birds were observed foraging on mistletoes. Our results show that mistletoes are important in promoting a higher bird species richness and abundance in tropical agricultural landscapes.

  16. Population Structure of Phytophthora infestans in the Toluca Valley Region of Central Mexico.

    Science.gov (United States)

    Grünwald, N J; Flier, W G; Sturbaum, A K; Garay-Serrano, E; van den Bosch, T B; Smart, C D; Matuszak, J M; Lozoya-Saldaña, H; Turkensteen, L J; Fry, W E

    2001-09-01

    ABSTRACT We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture (VALLEY). Isolates were sampled in 1988-89 (n= 179) and in 1997-98 (n= 389). In both sampling periods, the greatest genetic diversity was observed in RURAL and VALLEY habitats. Based on the Glucose-6-phosphate isomerase and Peptidase allozymes, the subpopulations from the three habitats were significantly differentiated in both sampling periods. In contrast to allozyme data for 1997-98, no differences were found among the three subpopulations for sensitivity to metalaxyl. Two groups of isolates identical for allozyme and mating type were further investigated by restriction fragment length polymorphism fingerprinting; 65% of one group and 85% of another group were demonstrated to be unique. The genetic diversity data and the chronology of disease occurrence during the season are consistent with the hypothesis that populations of P. infestans on wild Solanum populations are derived from populations on cultivated potatoes in the central highlands of Mexico near Toluca.

  17. Identification of a hyperendemic area for Trypanosoma cruzi infection in central Veracruz, Mexico.

    Science.gov (United States)

    Ramos-Ligonio, Angel; López-Monteon, Aracely; Guzmán-Gómez, Daniel; Rosales-Encina, José Luis; Limón-Flores, Yairh; Dumonteil, Eric

    2010-07-01

    The state of Veracruz, Mexico, is a well-recognized endemic region for Chagas disease, but the geographic distribution of the disease and its magnitude are still poorly documented. We evaluated the seroprevalence of Trypanosoma cruzi infection in the sanitary jurisdictions of Cordoba and Cosamaloapan in central Veracruz. A total of 654 serum samples from 19 rural localities were tested by using four tests: two enzyme-linked immunosorbent assays, an indirect immunofluorescent, and Western blotting. Overall, 110 (16.8%) of 654 samples were positive for T. cruzi by >/= 2 tests (95% confidence interval = 14.2-19.9%). The municipality of Tezonapa in the jurisdiction of Cordoba was identified as a potential hyperendemic region with seroprevalence rates

  18. Identification of a Hyperendemic Area for Trypanosoma cruzi Infection in Central Veracruz, Mexico

    Science.gov (United States)

    Ramos-Ligonio, Angel; López-Monteon, Aracely; Guzmán-Gómez, Daniel; Rosales-Encina, José Luis; Limón-Flores, Yairh; Dumonteil, Eric

    2010-01-01

    The state of Veracruz, Mexico, is a well-recognized endemic region for Chagas disease, but the geographic distribution of the disease and its magnitude are still poorly documented. We evaluated the seroprevalence of Trypanosoma cruzi infection in the sanitary jurisdictions of Cordoba and Cosamaloapan in central Veracruz. A total of 654 serum samples from 19 rural localities were tested by using four tests: two enzyme-linked immunosorbent assays, an indirect immunofluorescent, and Western blotting. Overall, 110 (16.8%) of 654 samples were positive for T. cruzi by ≥ 2 tests (95% confidence interval = 14.2–19.9%). The municipality of Tezonapa in the jurisdiction of Cordoba was identified as a potential hyperendemic region with seroprevalence rates ≤ 45% in young children. No cases were detected in the jurisdiction of Cosamaloapan. Further studies should help clarify T. cruzi transmission dynamics in Tezonapa. The magnitude of T. cruzi infection rate in this region calls for the urgent implementation of extensive epidemiologic surveillance and control programs. PMID:20595496

  19. [Validation of two indices of biological integrity (IBI) for the Angulo River subbasin in Central Mexico].

    Science.gov (United States)

    Ramírez-Herrejón, Juan Pablo; Mercado-Silva, Norman; Medina-Nava, Martina; Domínguez-Domínguez, Omar

    2012-12-01

    Efforts to halt freshwater ecosystem degradation in central Mexico can benefit from using bio-monitoring tools that reflect the condition of their biotic integrity. We analyzed the applicability of two fish-based indices of biotic integrity using data from lotic and lentic systems in the Angulo River subbasin (Lerma-Chapala basin). Both independent data from our own collections during two consecutive years, and existing information detailing the ecological attributes of each species, were used to calculate indices of biological integrity for 16 sites in lotic and lentic habitats. We assessed environmental quality by combining independent evaluations water and habitat quality for each site. We found sites with poor, regular and good biotic integrity. Our study did not find sites with good environmental quality. Fish-based IBI scores were strongly and significantly correlated with scores from independent environmental assessment techniques. IBI scores were adequate at representing environmental conditions in most study sites. These results expand the area where a lotic system fish-based IBI can be used, and constitute an initial validation of a lentic system fish-based IBI. Our results suggest that these bio-monitoring tools can be used in future conservation efforts in freshwater ecosystems in the Middle Lerma Basin.

  20. Morphological variation and the process of domestication of Stenocereus stellatus (Cactaceae) in Central Mexico.

    Science.gov (United States)

    Casas, A; Caballero, J; Valiente-Banuet, A; Soriano, J A; Dávila, P

    1999-04-01

    Morphological variation was analyzed in wild, managed in situ, and cultivated populations of the columnar cactus Stenocereus stellatus in central Mexico. The purpose was to evaluate whether morphological divergence between manipulated and wild populations has resulted from domestication processes. Variation of 23 morphological characters was analyzed among 324 individuals from 19 populations of the Tehuacán Valley and La Mixteca Baja. Multivariate statistical analyses were used to group individuals and populations according to their morphological similarity. Individuals grouped according to the way of management and fruit characteristics were the most relevant for grouping. Within each region, sweet fruits with pulp colors other than red were more frequent in cultivated populations, where fruits were also larger, contained more and bigger seeds, and had thinner peel and fewer spines than fruits from wild individuals. Phenotypes common in managed in situ and cultivated populations generally occur in the wild but in lower frequencies. Artificial selection has thus operated by enhancing and maintaining desirable rare phenotypes in managed in situ and cultivated populations, causing divergent patterns of morphological variation from wild populations. Cultivation has caused the strongest level of divergence, but divergence has also been significant with management of wild populations in situ.

  1. Water Quality of a Reservoir and Its Major Tributary Located in East-Central Mexico

    Directory of Open Access Journals (Sweden)

    Patricia Castilla-Hernández

    2014-06-01

    Full Text Available A reservoir with ecological and economic importance and its major tributary, localized in east-central Mexico, were studied. The aim of this work was to know the physicochemical water characteristics of both water bodies and to contrast these by their different uses, and also estimate overall water quality using a Water Quality Index (WQI. Water samples from the reservoir and the tributary were obtained in different climatic seasons. In the tributary, anoxic and hypoxic conditions and high levels of organic matter, orthophosphate, and ammonium showed that this is strongly impacted by wastewater discharges and that the water is not suitable for different uses; independently of the season, the WQI showed “poor” quality (34.4–47.2. In contrast, in the reservoir a better water quality was determined; the WQI in the sampling months ranged from 72.1–76.6 (“good” quality, and spatially, this was from 66.5–79.5 (“fair” and “good” quality.

  2. Water Quality of a Reservoir and Its Major Tributary Located in East-Central Mexico

    Science.gov (United States)

    Castilla-Hernández, Patricia; Torres-Alvarado, María del Rocío; Herrera-San Luis, José Antonio; Cruz-López, Norma

    2014-01-01

    A reservoir with ecological and economic importance and its major tributary, localized in east-central Mexico, were studied. The aim of this work was to know the physicochemical water characteristics of both water bodies and to contrast these by their different uses, and also estimate overall water quality using a Water Quality Index (WQI). Water samples from the reservoir and the tributary were obtained in different climatic seasons. In the tributary, anoxic and hypoxic conditions and high levels of organic matter, orthophosphate, and ammonium showed that this is strongly impacted by wastewater discharges and that the water is not suitable for different uses; independently of the season, the WQI showed “poor” quality (34.4–47.2). In contrast, in the reservoir a better water quality was determined; the WQI in the sampling months ranged from 72.1–76.6 (“good” quality), and spatially, this was from 66.5–79.5 (“fair” and “good” quality). PMID:24919132

  3. Modeling susceptibility to deforestation of remaining ecosystems in North Central Mexico with logistic regression

    Institute of Scientific and Technical Information of China (English)

    L. Miranda-Aragón; E.J. Trevi(n)o-Garza; J. Jiménez-Pérez; O.A. Aguirre-Calderón; M.A. González-Tagle; M. Pompa-García; C.A. Aguirre-Salado

    2012-01-01

    Determining underlying factors that foster deforestation and delineating forest areas by levels of susceptibility are of the main challenges when defining policies for forest management and planning at regional scale.The susceptibility to deforestation of remaining forest ecosystems (shrubland,temperate forest and rainforest) was conducted in the state of San Luis Potosi,located in north central Mexico.Spatial analysis techniques were used to detect the deforested areas in the study area during 1993-2007.Logistic regression was used to relate explanatory variables (such as social,investment,forest production,biophysical and proximity factors) with susceptibility to deforestation to construct predictive models with two focuses:general and by biogeographical zone.In all models,deforestation has positive correlation with distance to rainfed agriculture,and negative correlation with slope,distance to roads and distance to towns.Other variables were significant in some cases,but in others they had dual relationships,which varied in each biogeographical zone.The results show that the remaining rainforest of Huasteca region is highly susceptible to deforestation.Both approaches show that more than 70% of the current rainforest area has high and very high levels of susceptibility to deforestation.The values represent a serious concern with global warming whether tree carbon is released to atmosphere.However,after some considerations,encouraging forest environmental services appears to be the best alternative to achieve sustainabie forest management.

  4. Evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacan Valley, central Mexico: reproductive biology.

    Science.gov (United States)

    Otero-Arnaiz, Adriana; Casas, Alejandro; Bartolo, Carmen; Pérez-Negrón, Edgar; Valiente-Banuet, Alfonso

    2003-04-01

    Polaskia chichipe, a columnar cactus, is cultivated for its edible fruits in central Mexico. This study analyzed whether artificial selection has modified its reproduction patterns and caused barriers to pollen exchange between wild, managed in situ, and cultivated populations. Anthesis was diurnal (∼16 h in winter, ∼10 h in spring) as well as partly nocturnal (∼12 h in winter, ∼3 h in spring), and flowers were pollinated by bees, hummingbirds, and hawk moths. Manual cross-pollination was ∼37-49% effective in all populations. Self-pollination was ∼12% successful in the wild, but twice as successful (∼22-27%) in managed and cultivated populations. Diurnal pollination was ∼35-55% effective in winter and 100% in spring. Nocturnal pollination was successful only in winter (15%). Crosses among individuals were more effective within populations than among populations, including populations under a similar management regimen. The least successful crosses were between wild and cultivated populations. Flowers were produced in all populations from January to March, but flowering peaks differed by 1 mo among wild, managed, and cultivated populations and by 2 mo between wild and cultivated populations. The latter interrupted pollen exchange in May. Seeds from managed and cultivated populations germinated faster than those from wild individuals. Domestication has seemingly favored self-compatible P. chichipe plants with higher fruit yield, a longer period of fruit production, and faster seed germination, attributes that have resulted in partial reproductive barriers between wild and manipulated populations.

  5. Geothermal potential of West-Central New Mexico from geochemical and thermal gradient data

    Energy Technology Data Exchange (ETDEWEB)

    Levitte, D.; Gambill, D.T.

    1980-11-01

    To study the low temperature and Hot Dry Rock (HDR) geothermal potential of west-central New Mexico, 46 water samples were collected and geothermal gradient measurements were made in 29 wells. Water chemistry data indicate that all the samples collected are meteoric waters. High temperatures of samples taken from wells between Gallup and Tohatchi indicate these wells may derive water from a warm aquifer below the depth of the wells. The chemistries of the samples farther south on the Zuni Indian reservation suggest these waters are not circulating below 600 m of the surface. Geothermometry calculations support the conclusion that the waters sampled are meteoric. The geothermometry also indicates that the deep reservoir between Gallup and Tohatchi may be greater than 60/sup 0/C. Thermal gradient data indicate an area of high gradient on the Zuni Indian Reservation with a measured maximum of 67/sup 0/C/km between 181 m and 284 m. This high probably is not hydrologically controlled. The maximum gradients in the study area are 76/sup 0/C/km and 138/sup 0/C/km, measured just east of Springerville, Arizona. These gradients are undoubtedly controlled by circulating water, possibly heated by a magmatic source at depth and circulating back to the surface.

  6. Techniques for verifying human footprints: reappraisal of pre-Clovis footprints in Central Mexico

    Science.gov (United States)

    Morse, Sarita Amy; Bennett, Matthew R.; Gonzalez, Silvia; Huddart, David

    2010-09-01

    Verification of human footprints within the geological record provides critical evidence of presence as well as information on the biomechanics of the individuals who made those prints. Consequently, the correct identification of human footprints is important, but is something for which critical and objective criteria do not exist. The current paper attempts to address this issue by presenting a new statistically based approach to the verification of human footprints. The importance of this is illustrated by the recent controversy surrounding a series of marks identified as human prints in the Valsequillo Basin in Central Mexico dated originally to 40 000 years ago. The dating of these marks remains highly controversial with some teams placing their age at 1.3 million years old. Irrespective of this debate the crucial question that must be addressed is whether or not they represent evidence of human presence. Using an objective statistically based methodology developed here, these controversial marks are re-examined and found to be of questionable origin, as they are inconsistent with a suite of other, known human and hominin prints. Consequently, we argue that they should be removed as evidence in the ongoing controversy surrounding the colonization of the Americas.

  7. On the age of human footprints in Central Mexico: paleomagnetic constraints

    Science.gov (United States)

    Rocha Fernandez, J.; Gogichaishvili, A.; Martin Del Pozo, A.; Urrutia Fucugauchi, J.

    2007-05-01

    Until recently, we thought we knew where ancestral Native Americans came from (central Siberia, then across Beringia), and when they arrived (about 13 000 cal BP, after a trek between the recently separated Canadian ice sheets after Fiedel, 2006). Recent theories of American origins postulate multiple pre-Clovis migrations including Transpacific or coastal voyages by Australians, Melanesians, or Ainu, and even a Transatlantic migrations by Caucasoid Solutreans from Iberia. Thus, timing, route and origin of the first colonization to the Americas remains one of the most important topics in human evolution. Human and animal footprints have been found within the upper bedding surfaces of the Xalnene volcanic ash layer that outcrops in the Valsequillo Basin, south of Puebla, Mexico (Gonzalez et al., 2005). The ash has been dated to at least 40 ka BP. Paleomagnetic investigation yielded an intermediate magnetic polarity for Xalnene ash deposits while nearby Toluquilla volcano is reversely magnetized. Moreover, the absolute geomagnetic paleointensity derived from the volcanic lava flow is significantly reduced with respect to the present day geomagnetic field strength. It is quite possible that the ash as well as volcanic lava flow formed during worldwide observed Laschamp geomagnetic event.

  8. Students and Teachers’ Reasons for Using the First Language Within the Foreign Language Classroom (French and English) in Central Mexico

    OpenAIRE

    Mora Pablo Irasema; Lengeling M. Martha; Rubio Zenil Buenaventura; Crawford Troy; Goodwin Douglas

    2011-01-01

    The present study explores the use of the first language in a context of foreign language teaching. This qualitative research presents the classroom practice and points of view of French and English teachers and students within a public educational institute in central Mexico using the techniques of questionnaires and semi-structured interviews. The results show that teachers and the majority of students perceive the use of the first language as positive and part of the teaching and ...

  9. Annotated bibliography of the hydrology, geology, and geothermal resources of the Jemez Mountains and vicinity, north-central New Mexico

    Science.gov (United States)

    Abeyta, Cynthia G.; Delaney, B.M.

    1986-01-01

    The Jemez Mountains volcanic complex, located in north-central New Mexico at the intersection of the Rio Grande rift and Jemez lineament, is a potential location for geothermal energy exploration. This bibliography lists selected papers pertaining to the geology, hydrology, geochemistry, geothermometry, geophysics, ecology, and geothermal and hydrologic modeling aspects of the Jemez region. The bibliography is composed of 795 citations with annotations and a subject and author index. (USGS)

  10. Geology of the State of Morelos and contiguous areas in south-central Mexico

    Science.gov (United States)

    Fries, Carl F.

    1959-01-01

    The area described lies in south-central Mexico and embraces all but the southeastern corner and easternmost border of the State of Moreles, the second smallest State in the Mexican Republic. It includes small contiguous parts of the State of Mexico, in the northeastern corner, and of the State of Guerrero in the southwestern corner. Limiting geographic coordinates are 98 45 to 99 39 west longitude and 18 18 to 19 08 north latitude, the northern boundary being only 35 km south of Mexico City, capital of the Republic. The geological map does not cover the entire rectangle outlined, but is irregular in form and measures roughly 4150 sq. km, three-quarters of it representing two0thirds of the State of Moreles and the rest lying outside the State. The region ranges in altitude from 730 m above sea level at Iguala near the south edge of the map, to a general level of about 3000 m at the north edge, although individual peaks rise to 3900 m and Popocatepetl Volcano, a few kilometers east of the northeastern border of the map, rises to 5452 m above sea level. Annual rainfall ranges from a minimum of about 640 mm in the low country, to 1200 mm and more at altitudes above 2000 m. Most of it falls in summer between June and September. Winter frosts are rare below 1800 m. The climate is of savanna to steppe type; soils are thin and may be classified as belonging to the tachernoses group, with strong development of calcareous evaporates (caliche) at altitudes below 1800 m. The northern border of the area forms the southern half of the late Pliocene to Recent Neo-volcanic Belt of basic volcanism that crosses Mexico in the direction N. 80 W., and thus has constructional topography. The rest of the area belongs to the Balsas Basin physiographic province, which is characterized by maturely dissected terrain tributary to the large Balsas River. All but the southwestern corner of the area drains southward via the Amacuzac River into the Mexcala-Balsas River, and thence westward into

  11. Regionalization and classification of bioclimatic zones in the central-northeastern region of Mexico using principal component analysis (PCA)

    Energy Technology Data Exchange (ETDEWEB)

    Pineda-Martinez, L.F.; Carbajal, N.; Medina-Roldan, E. [Instituto Potosino de Investigacion Cientifica y Tecnologica, A. C., San Luis Potosi (Mexico)]. E-mail: lpineda@ipicyt.edu.mx

    2007-04-15

    Applying principal component analysis (PCA), we determined climate zones in a topographic gradient in the central-northeastern part of Mexico. We employed nearly 30 years of monthly temperature and precipitation data at 173 meteorological stations. The climate classification was carried out applying the Koeppen system modified for the conditions of Mexico. PCA indicates a regionalization in agreement with topographic characteristics and vegetation. We describe the different bioclimatic zones, associated with typical vegetation, for each climate using geographical information systems (GIS). [Spanish] Utilizando un analisis de componentes principales, determinamos zonas climaticas en un gradiente topografico en la zona centro-noreste de Mexico. Se emplearon datos de precipitacion y temperatura medias mensuales por un periodo de 30 anos de 173 estaciones meteorologicas. La clasificacion del clima fue llevada a cabo de acuerdo con el sistema de Koeppen modificado para las condiciones de Mexico. El analisis de componentes principales indico una regionalizacion que concuerda con caracteristicas de topografia y vegetacion. Se describen zonas bioclimaticas, asociadas a vegetacion tipica para cada clima, usando sistemas de informacion geografica (SIG).

  12. Semiarid watershed response in central New Mexico and its sensitivity to climate variability and change

    Directory of Open Access Journals (Sweden)

    E. R. Vivoni

    2009-06-01

    Full Text Available Hydrologic processes in the semiarid regions of the Southwest United States are considered to be highly susceptible to variations in temperature and precipitation characteristics due to the effects of climate change. Relatively little is known about the potential impacts of climate change on the basin hydrologic response, namely streamflow, evapotranspiration and recharge, in the region. In this study, we present the development and application of a continuous, semi-distributed watershed model for climate change studies in semiarid basins of the Southwest US. Our objective is to capture hydrologic processes in large watersheds, while accounting for the spatial and temporal variations of climate forcing and basin properties in a simple fashion. We apply the model to the Río Salado basin in central New Mexico since it exhibits both a winter and summer precipitation regime and has a historical streamflow record for model testing purposes. Subsequently, we use a sequence of climate change scenarios that capture observed trends for winter and summer precipitation, as well as their interaction with higher temperatures, to perform long-term ensemble simulations of the basin response. Results of the modeling exercise indicate that precipitation uncertainty is amplified in the hydrologic response, in particular for processes that depend on a soil saturation threshold. We obtained substantially different hydrologic sensitivities for winter and summer precipitation ensembles, indicating a greater sensitivity to more intense summer storms as compared to more frequent winter events. In addition, the impact of changes in precipitation characteristics overwhelmed the effects of increased temperature in the study basin. Nevertheless, combined trends in precipitation and temperature yield a more sensitive hydrologic response throughout the year.

  13. Inversion polymorphism in some natural populations of Drosophila pseudoobscura from central Mexico

    Directory of Open Access Journals (Sweden)

    Salceda Víctor M.

    2007-01-01

    Full Text Available Samples of D. pseudoobscura were taken in seventeen localities in Central Mexico inside the parallels 18o - 20o N, with the purpose of determine the chromosomal polymorphism in the third of the different populations of this species. From each captured female a single larva of its offspring was taken, its salivary glands extracted and stained with a solution of aceto orcein to observe the polytene chromosomes. From these smears the corresponding karyotype of each larva was determined, keeping a record of them. With the information gathered the relative frequency of each one of the fourteen different inversions found was calculated. A grand total of 1894 third chromosomes were analyzed. The fourteen different inversions found are equivalent to a 34.1 % of the total chromosomal variation of the species. The most abundant inversions found were: TL 50.6 %, CU 27.2 5, SC 9.1 % and EP 5.5 %; the remaining ten inversions detected are in general grounds rare ones with variable relative frequencies depending on the locality. Analysis of the predominant inversions for each population was done. The presence of West-East gradients is reported, even if in cases not so well defined, since as one moves in a particular direction the ups and downs in relative frequency for the alternating pairs TL-CU; TL-SC in the western populations and TL-CU in the eastern ones were observed. The assignment of each population to a particular race was also done, and such a way we were able to recognize three different races coexisting in the area of study.

  14. Gastrointestinal nematodes in rotationally grazing ewes in the mountainous region of central Mexico.

    Science.gov (United States)

    Acevedo-Ramírez, P M C; Quiroz-Romero, H; Cruz-Mendoza, I; Ulloa-Arvizu, R; Ibarra-Velarde, F

    2013-03-01

    The aims of this study were to determine the frequency of egg shedding (percentage of egg-positive faecal samples) and faecal egg counts (FEC) over 13 months in two different breeds of ewes, both pregnant and non-pregnant, in a mountainous region of central Mexico. Additionally, the effect of ivermectin and albendazole treatments on FEC reduction was recorded. The study also aimed to relate temperature and rainfall to FEC. The gastrointestinal nematode (GIN) third-stage larvae genera recovered from both faeces and grassland pastures in a temperate region were also assessed. Faecal samples were collected from ewes at monthly intervals for 13 months to investigate the FEC population of GIN larvae, their concentration and genera in grass samples collected from grazed and rested pastures. Egg-shedding frequency ranged from 0 to 92% and FEC from 0 to 12,000 eggs per g faeces (epg), with counts in Suffolk higher than in Dorset ewes. The identified genera were Haemonchus, Trichostrongylus, Teladorsagia, Cooperia, Oesophagostomum, Bunostomum, Nematodirus and Strongyloides. Haemonchus and Trichostrongylus were the most common genera. The number of L3 was higher in grazing lands than in those at rest. The highest FEC were recorded in the dry season due to peripartum, but the highest L3 counts were recorded in the rainy season. The coexistence of species of different geographical distributions at this site may be because there is a confluence of Nearctic and Neotropical geographic regions; thus, despite the temperate climate, tropical species can be found. Additionally, this study suggests that increasing temperatures could favour the presence of different tropical GIN species together with typical temperate-zone GIN species.

  15. Genetic diversity of Taenia solium cysticerci from naturally infected pigs of central Mexico.

    Science.gov (United States)

    Bobes, Raúl J; Fragoso, Gladis; Reyes-Montes, María del Rocio; Duarte-Escalante, Esperanza; Vega, Rodrigo; de Aluja, Aline S; Zúñiga, Gerardo; Morales, Julio; Larralde, Carlos; Sciutto, Edda

    2010-02-26

    This study was designed to explore if each individual case of naturally acquired porcine cysticercosis, living in different geographic rural areas of central Mexico, is caused by one or more different specimens of Taenia solium tapeworm. The genetic variability among cysticerci from the same pig and that from different pigs was assessed by random amplified polymorphic DNA markers (RAPDs), through the percentage of polymorphic loci, the number of effective alleles, the expected heterozygosity and the Shannon index. The parasite population's reproductive structure was estimated through the association index (I(A)), and the degree of genetic differentiation and variation was determined using AMOVA. Using six different random primers, and a total of 181 cysticerci from 14 pigs, 88 different loci were amplified: 85% were polymorphic between pigs and 24% within pigs. The phenogram grouped the cysticerci into eight major clusters, with differences in the genetic distances among all cysticerci from 14 pigs ranging from 0.78 to 1. Most of the cysticerci grouped in accord with their different geographical origin and with their pig of origin. The similarity matrix produced from the phenogram (obtained by UPGMA) and the original similarity matrix yielded a good cophenetic correlation (r=0.82317, P=0.0004), which suggests that the phenogram accurately represents the original genetic similarities between isolates. The combination of I(A) (0.0-0.089) with the genetic diversity index (0.009-0.073) supports the idea that DNA diversity in T. solium cysticerci of naturally infected pigs is within the range expected from a recombination process occurring during sexual reproduction. The small genetic diversity found within the cysticerci of each pig (33.81%), when compared with that between pigs (66.19%), indicates that pigs are rarely infected by different tapeworms. It would then appear that porcine cysticercosis courses with effective concomitant immunity, as occurs in ovine

  16. Late Pleistocene and Holocene environmental history of the Iguala Valley, Central Balsas Watershed of Mexico.

    Science.gov (United States)

    Piperno, D R; Moreno, J E; Iriarte, J; Holst, I; Lachniet, M; Jones, J G; Ranere, A J; Castanzo, R

    2007-07-17

    The origin of agriculture was a signal development in human affairs and as such has occupied the attention of scholars from the natural and social sciences for well over a century. Historical studies of climate and vegetation are closely associated with crop plant evolution because they can reveal the ecological contexts of plant domestication together with the antiquity and effects of agricultural practices on the environment. In this article, we present paleoecological evidence from three lakes and a swamp located in the Central Balsas watershed of tropical southwestern Mexico that date from 14,000 B.P. to the modern era. [Dates expressed in B.P. years are radiocarbon ages. Calibrated (calendar) ages, expressed as cal B.P., are provided for dates in the text.] Previous molecular studies suggest that maize (Zea mays L.) and other important crops such as squashes (Cucurbita spp.) were domesticated in the region. Our combined pollen, phytolith, charcoal, and sedimentary studies indicate that during the late glacial period (14,000-10,000 B.P.), lake beds were dry, the climate was cooler and drier, and open vegetational communities were more widespread than after the Pleistocene ended. Zea was a continuous part of the vegetation since at least the terminal Pleistocene. During the Holocene, lakes became important foci of human activity, and cultural interference with a species-diverse tropical forest is indicated. Maize and squash were grown at lake edges starting between 10,000 and 5,000 B.P., most likely sometime during the first half of that period. Significant episodes of climatic drying evidenced between 1,800 B.P. and 900 B.P. appear to be coeval with those documented in the Classic Maya region and elsewhere, showing widespread instability in the late Holocene climate.

  17. Limitations and potentials of dual-purpose cow herds in Central Coastal Veracruz, Mexico.

    Science.gov (United States)

    Absalón-Medina, Victor Antonio; Blake, Robert W; Fox, Danny Gene; Juárez-Lagunes, Francisco I; Nicholson, Charles F; Canudas-Lara, Eduardo G; Rueda-Maldonado, Bertha L

    2012-08-01

    Feed chemical and kinetic composition and animal performance information was used to evaluate productivity limitations and potentials of dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. The Cornell Net Carbohydrate and Protein System model (Version 6.0) was systematically applied to specific groups of cows in structured simulations to establish probable input-output relationships for typical management, and to estimate probable outcomes from alternative management based on forage-based dietary improvements. Key herd vulnerabilities were pinpointed: chronic energy deficits among dry cows of all ages in late gestation and impeded growth for immature cows. Regardless of the forage season of calving, most cows, if not all, incur energy deficits in the final trimester of gestation; thus reducing the pool of tissue energy and constraining milking performance. Under typical management, cows are smaller and underweight for their age, which limits feed intake capacity, milk production and the probability of early postpartum return to ovarian cyclicity. The substitution of good-quality harvested forage for grazing increased predicted yields by about one-third over typical scenarios for underweight cows. When diets from first parturition properly supported growth and tissue repletion, milk production in second and third lactations was predicted to improve about 60%. Judiciously supplemented diets based on good quality grass and legume forages from first calving were predicted to further increase productivity by about 80% across a three-lactation cow lifetime. These dual-purpose herd owners have large incentives to increase sales income by implementing nutritional strategies like those considered in this study.

  18. Agave salmiana Plant Communities in Central Mexico as Affected by Commercial Use

    Science.gov (United States)

    Martínez Salvador, Martin; Mata-González, Ricardo; Morales Nieto, Carlos; Valdez-Cepeda, Ricardo

    2012-01-01

    Agave salmiana is a native plant species harvested for the commercial production of mezcal ( Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were identified in the state of Zacatecas based on their history of A. salmiana utilization: short (less than 10 years of use), moderate (about 25 years), and long (60 or more years). Species cover, composition, and density were evaluated in field surveys by use category. A gradient of vegetation structure of the communities parallels the duration of A. salmiana use. A. salmiana density was greatest (3,125 plants ha-1) in the short-use areas and less (892 plants ha-1) in the moderate-use areas, associated with markedly greater density of shrubs (200%) and Opuntia spp. (50%) in moderate-use areas. The main shrubs were Larrea tridentata, Mimosa biuncifera, Jatropha dioica and Buddleia scordioides while the main Opuntia species were Opuntia leucotricha and Opuntia robusta. A. salmiana density was least (652 plants ha-1) in the long-use areas where shrubs were less abundant but Opuntia spp. density was 25% higher than in moderate-use areas. We suggest that shrubs may increase with moderate use creating an intermediate successional stage that facilitates the establishment of Opuntia spp. Long-term Agave use is generating new plant communities dominated by Opuntia spp. (nopaleras) as a replacement of the original communities dominated by A. salmiana (magueyeras).

  19. Ecosystem service trade-offs, perceived drivers, and sustainability in contrasting agroecosystems in central Mexico

    Directory of Open Access Journals (Sweden)

    Carlos E. González-Esquivel

    2015-03-01

    Full Text Available The ability of agroecosystems to provide food ultimately depends on the regulating and supporting ecosystem services that underpin their functioning, such as the regulation of soil quality, water quality, soil erosion, pests, and pollinators. However, there are trade-offs between provisioning and regulating or supporting services, whose nature at the farm and plot scales is poorly understood. We analyzed data at the farm level for two agroecosystems with contrasting objectives in central Mexico: one aimed at staple crop production for self-subsistence and local markets, the other directed to a cash crop for export markets. Bivariate and multivariate trade-offs were analyzed for different crop management strategies (conventional, organic, traditional, crop rotation and their underpinning socioeconomic drivers. There was a clear trade-off between crop yield and soil quality in self-subsistence systems. However, other expected trade-offs between yields and soil quality did not always occur, likely because of the overall good soils of the region and the low to medium input profile of most farms. Trade-offs were highly dependent on farm-specific agricultural practices; organic, traditional, and rotation management systems generally showed smaller trade-offs between yield and soil quality, pest control, and biodiversity than did conventional management systems. Perceived drivers reported by farmers included increasing prices for cash crops, rising costs of inputs, and extreme climatic events (e.g., drought, hail, frost. Farmers did not identify the regulation of soil quality, water quality, soil erosion, pests, or pollinators as important constraints. Although acceptable yields could be maintained irrespective of key regulating and supporting services according to these perceptions, current levels of soil erosion and nutrient runoff are likely to have important negative effects at the watershed scale. Sustainability in both agroecosystems could be

  20. Late Pleistocene flank collapse of Zempoala volcano (Central Mexico) and the role of fault reactivation

    Science.gov (United States)

    Arce, José Luis; Macías, Rodolfo; García Palomo, Armando; Capra, Lucia; Macías, José Luis; Layer, Paul; Rueda, Hernando

    2008-11-01

    Zempoala is an extinct Pleistocene (˜ 0.7-0.8 Ma) stratovolcano that together with La Corona volcano (˜ 0.9 Ma) forms the southern end of the Sierra de las Cruces volcanic range, Central Mexico. The volcano consists of andesitic and dacitic lava flows and domes, as well as pyroclastic and epiclastic sequences, and has had a complex history with several flank collapses. One of these collapses occurred during the late Pleistocene on the S-SE flank of the volcano and produced the Zempoala debris avalanche deposit. This collapse could have been triggered by the reactivation of two normal fault systems (E-W and NE-SW), although magmatic activity cannot be absolutely excluded. The debris avalanche traveled 60 km to the south, covers an area of 600 km 2 and has a total volume of 6 km 3, with a calculated Heim coefficient (H/L) of 0.03. Based on the textural characteristics of the deposit we recognized three zones: proximal, axial, and lateral distal zone. The proximal zone consists of debris avalanche blocks that develop a hummocky topography; the axial zone corresponds with the main debris avalanche deposit made of large clasts set in a sandy matrix, which transformed to a debris flow in the lateral distal portion. The deposit is heterolithologic in composition, with dacitic and andesitic fragments from the old edifice that decrease in volume as bulking of exotic clasts from the substratum increase. Several cities (Cuernavaca, Jojutla de Juárez, Alpuyeca) with associated industrial, agricultural, and tourism activities have been built on the deposit, which pose in evidence the possible impact in case of a new event with such characteristics, since the area is still tectonically active.

  1. Agave salmiana plant communities in central Mexico as affected by commercial use.

    Science.gov (United States)

    Martínez Salvador, Martin; Mata-González, Ricardo; Morales Nieto, Carlos; Valdez-Cepeda, Ricardo

    2012-01-01

    Agave salmiana is a native plant species harvested for the commercial production of mezcal (Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were identified in the state of Zacatecas based on their history of A. salmiana utilization: short (less than 10 years of use), moderate (about 25 years), and long (60 or more years). Species cover, composition, and density were evaluated in field surveys by use category. A gradient of vegetation structure of the communities parallels the duration of A. salmiana use. A. salmiana density was greatest (3,125 plants ha(-1)) in the short-use areas and less (892 plants ha(-1)) in the moderate-use areas, associated with markedly greater density of shrubs (200%) and Opuntia spp. (50%) in moderate-use areas. The main shrubs were Larrea tridentata, Mimosa biuncifera, Jatropha dioica and Buddleia scordioides while the main Opuntia species were Opuntia leucotricha and Opuntia robusta. A. salmiana density was least (652 plants ha(-1)) in the long-use areas where shrubs were less abundant but Opuntia spp. density was 25% higher than in moderate-use areas. We suggest that shrubs may increase with moderate use creating an intermediate successional stage that facilitates the establishment of Opuntia spp. Long-term Agave use is generating new plant communities dominated by Opuntia spp. (nopaleras) as a replacement of the original communities dominated by A. salmiana (magueyeras).

  2. Soil Survey Geographic (SSURGO) database for Grant County, Central and Southern Parts, New Mexico

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil Survey. The...

  3. Bathymetry Mapping of the West Florida Shelf (Central Region), Gulf of Mexico (NODC Accession 0001410)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XYZ ASCII format data generated from the 2001 multibeam sonar survey of the West Florida Shelf, Gulf of Mexico. The data include high-resolution bathymetry and...

  4. Backscatter Mapping of the West Florida Shelf (Central Region), Gulf of Mexico (NODC Accession 0001410)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XYZ ASCII format data generated from the 2001 multibeam sonar survey of the West Florida Shelf, Gulf of Mexico. The data include high-resolution bathymetry and...

  5. Eolic central Guerrero Negro, BCS, Mexico, performance first year operation; Central eolica Guerrero Negro, BCS, Mexico, resultados del primer ano de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Cadenas Tovar, Roberto; Sanchez Cornejo, Carlos; Lopez Rios, Serafin [Comision Federal de Electricidad, Morelia, Michoacan (Mexico); Ley Romero, Jose R [Comision Federal de Electricidad, Guerrero Negro, Baja California Sur (Mexico)

    2000-07-01

    Comision Federal de Electricidad installed a 600 kW wind turbine in the Guerrero Negro isolated electrical grid to evaluate, under actual operation conditions, the contribution of wind energy in the generation of electricity. This paper describes the performance of the wind turbine in terms of its availability, power curve and electricity produced. The results have been satisfactory, electricity was supplied with a lesser fuel consumption than before. [Spanish] La Comision Federal de Electricidad instalo en Guerrero Negro, Baja California Sur, Mexico un aerogenerador de 600 kW para evaluar en condiciones reales de operacion la integracion de la energia del viento a sistemas electricos aislados basados en diesel. En este trabajo se describen los resultados del primer ano de operacion del aerogenerador en terminos de su disponibilidad, curva de potencia y generacion obtenida. Los resultados han sido satisfactorios, registrandose una reduccion en el consumo de combustible fosil en el sistema.

  6. Environmental history of mangrove vegetation in Pacific west-central Mexico during the last 1300 years

    Directory of Open Access Journals (Sweden)

    Blanca Lorena Figueroa-Rangel

    2016-08-01

    Full Text Available AbstractMangroves are a highly threatened ecosystem due to climate change and human activity, which increases coastal vulnerability. Knowledge about the ecological dynamics of mangroves on a centennial timescale can reveal the different responses in vegetation, which is useful for implementing basic actions for mangrove restoration, conservation and management. A mangrove ecosystem in the Cuyutlán Lagoon area along the Pacific coast of west-central Mexico is significantly altered as a result of industrialization, salt extraction, and road construction. The long-term dynamics of the mangrove ecosystem has also been controlled by Holocene climatic variability. This study reconstructs the environmental history of mangrove vegetation around the Cuyutlán Lagoon during the last ~1300 years in response to periods of human activity and climate change. The reconstruction was performed using paleoecological techniques in sediment cores that include the use of fossil pollen as a proxy for vegetation and magnetic susceptibility and geochemical data (determined by loss-on-ignition and X-ray fluorescence as a proxy for past environmental changes. The chronology was determined using 14C dating and the age-depth model was constructed by linear interpolation. Redundancy analysis and non-metric multidimensional scaling (NMDS were used to discern patterns of distribution of the different proxies. Results revealed that the mangrove pollen assemblage of the Cuyutlán Lagoon was dominated by the arboreal taxa Rhizophora mangle, Euphorbiaceae, Moraceae and Pinaceae, herbaceous taxa like Poaceae, Chenopodiaceae/Amaranthaceae, and aquatics such as Typhaceae and Cyperaceae. NMDS showed a clear separation between two events of human activity—the Spanish Occupation of Colima (~AD 1523-1524 and the opening of the Manzanillo port (~AD 1824-1825. Climate change events such as the Medieval Climate Anomaly (MCA (~AD 800-1200 and the Little Ice Age (LIA (~AD 1350-1850 were

  7. Implementation of MAR within the Rio Grande Basin of Central New Mexico, USA

    Science.gov (United States)

    Marley, Robert; Blandford, T. Neil; Ewing, Amy; Webb, Larry; Yuhas, Katherine

    2014-05-01

    The U.S. Bureau of Reclamation has identified the Rio Grande basin within Central New Mexico as one of several regions where water supplies are over-allocated and future conflicts over the inadequate resource are highly likely. Local water providers have consistently identified managed aquifer recharge (MAR) as an important tool to provide conjunctive management of surface-water, groundwater, and reclaimed water sources in order to extend the useful life of existing water sources. However, MAR projects have been slow to take root partly due to rigorous demonstration requirements, groundwater quality protection concerns, and ongoing water right uncertainties. At first glance the several thousand meters of unconsolidated basin-fill sediments hosting the regional aquifer appear to provide an ideal environment for the subsurface storage of surplus water. However, the basin has a complex structural and depositional history that impacts the siting and overall effectiveness of MAR systems. Several recharge projects are now in various stages of implementation and are overcoming site specific challenges including source water and ambient groundwater compatibility, low-permeability sediments and compartmentalization of the aquifer by extensive faulting, well clogging, and overall water quality management. This presentation will highlight ongoing efforts of these water providers to develop full-scale recharge facilities. The performance of natural in-channel infiltration, engineered infiltration galleries, and direct injection systems designed to introduce from 500 to 5,000 mega-liters per annum to target intervals present from 150 to 600 meters below ground surface will be described. Source waters for recharge operations include inter-basin transferred surface water and highly treated reclaimed water sources requiring from minor to extensive treatment pre-recharge and post-recovery. Operational complexities have raised concerns related to long-term operation and maintenance

  8. Pleistocene glaciation of volcano Ajusco, central Mexico, and comparison with the standard Mexican glacial sequence

    Science.gov (United States)

    White, Sidney E.; Valastro, Salvatore

    1984-01-01

    Three Pleistocene glaciations and two Holocene Neoglacial advances occurred on volcano Ajusco in central Mexico. Lateral moraines of the oldest glaciation, the Marqués, above 3250 m are made of light-gray indurated till and are extensively modified by erosion. Below 3200 m the till is dark red, decomposed, and buried beneath volcanic colluvium and tephra. Very strongly to strongly developed soil profiles (Inceptisols) have formed in the Marqués till and in overlying colluvia and tephra. Large sharp-crested moraines of the second glaciation, the Santo Tomás, above 3300 m are composed of pale-brown firm till and are somewhat eroded by gullies. Below 3250 m the till is light reddish brown, cemented, and weathered. Less-strongly developed soil profiles (Inceptisols) have formed in the Santo Tomás till and in overlying colluvia and tephra. Narrow-crested moraines of yellowish-brown loose till of the third glaciation, the Albergue, are uneroded. Weakly developed soil profiles (Inceptisols) in the Albergue till have black ash in the upper horizon. Two small Neoglacial moraines of yellowish-brown bouldery till on the cirque floor of the largest valley support weakly developed soil profiles with only A and Cox horizons and no ash in the upper soil horizons. Radiocarbon dating of organic matter of the B horizons developed in tills, volcanic ash, and colluvial volcanic sand includes ages for both the soil-organic residue and the humic-acid fraction, with differences from 140 to 660 yr. The dating provides minimum ages of about 27,000 yr for the Marqués glaciation and about 25,000 yr for the Santo Tomás glaciation. Dates for the overlying tephra indicate a complex volcanic history for at least another 15,000 yr. Comparison of the Ajusco glacial sequence with that on Iztaccíhuatl to the east suggests that the Marqués and Santo Tomás glaciations may be equivalent to the Diamantes glaciation First and Second advances, the Albergue to the Alcalican glaciations, and the

  9. Formation conditions of the Rudny Altai metallogenic province

    Science.gov (United States)

    Kozlov, M. S.

    2015-07-01

    The results of previous geological, petrochemical, and metallogenic surveys conducted from the 1960s to the 1990s provide the geological and tectonic basis of this study. The unique mineral deposits of the Rudny Altai metallogenic province were formed in the Middle Paleozoic (S2-C1) at the junction between different structures of the Altai-Mongolian terrane: the Alei-Charysh-Tigirek rift (in the north) with the Korgon-Markakol' island arc and Belaya Uba-Maimyr intra-arc trough (in the southwest). The Rudny Altai structural-formational zone that formed at the junction between these structures evolved as a magmatic arc and was characterized by the formation of granite-greenschist arches, volcanoplutonic magmatism and high heat and fluid flow (greenschist-facies metamorphism of Upper Silurian-Upper Devonian rocks and deposition of pyrite-bearing hydrothermal-sedimentary horizons, VMS and copper-VMS deposits and isolated base-metal ore bodies). The tectonomagmatic history of the Rudny Altai zone can be subdivided into several stages: Ludlow-Emsian, Late Emsian-Givetian, Frasnian-Early Famennian, Middle Famennian-Early Visean, and Late Visean-Serpukhovian. The island arc is represented by volcanic rocks of the andesite-dacite-rhyolite (early stage), basalt-rhyolite (Late Emsian-Eifelian), and basalt-andesite-rhyolite series (Late Visean). Volcanosedimentary strata (until the Givetian age) and turbidites up to 3-5 km thick were deposited in the interarc trough. Because of their metastable behavior, the volcanic rocks became actively involved in ion-exchange reactions with the formational waters, whereas the differences in hydraulic head between arches and troughs created favorable conditions for the transport of the metamorphic fluids, and the thermal gradient promoted thermodiffusion of divalent species of Mg, Pb, Zn, Cu, etc. toward the high-temperature zone and development of the high-Mg metamorphic-metasomatic alteration with a VMS-base-metal mineralization. As a

  10. Genetic structure and diversity in an isolated population of an endemic mole salamander (Ambystoma rivulare Taylor, 1940) of central Mexico.

    Science.gov (United States)

    Heredia-Bobadilla, Rosa-Laura; Monroy-Vilchis, Octavio; Zarco-González, Martha M; Martínez-Gómez, Daniel; Mendoza-Martínez, Germán David; Sunny, Armando

    2016-12-01

    Human activities are affecting the distribution of species worldwide by causing fragmentation and isolation of populations. Isolation and fragmentation lead to populations with lower genetic variability and an increased chance of inbreeding and genetic drift, which results in a loss of biological fitness over time. Studies of the genetic structure of small and isolated populations are critically important for management and conservation decisions. Ambystoma rivulare is a micro-endemic Mexican mole salamander from central Mexico. It is found in the most ecologically disturbed region in Mexico, the Trans-Mexican Volcanic Belt. The goal of this study of the population genetics of the micro-endemic mole salamander was to provide information to be used as a basis for future research and conservation planning of this species and other species of the Ambystoma genus in Mexico. The structural analysis found two subpopulations, one for each river sampled, with no signs of admixture and very high levels of genetic differentiation. Medium to high levels of heterozygosity and few alleles and genotypes were observed. Evidence of an ancestral genetic bottleneck, low values of effective population size, small inbreeding coefficients, and low gene flow were also found.

  11. Gulf of Mexico Sales 147 and 150: Central and Western planning areas. Final environmental impact statement, Volume 1: Sections 1 through 4.C

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    This Final Environmental Impact Statement (EIS) covers the proposed 1994 Gulf of Mexico OCS oil and gas lease sales [Central Gulf of Mexico Sale 147 (March 1994) and Western Gulf of Mexico Sale 150 (August 1994)]. This document includes the purpose and background of the proposed actions, the alternatives, the descriptions of the affected environment, and the potential environmental impacts of the proposed actions and alternatives. Proposed mitigating measures and their effects are analyzed, in addition to potential cumulative impacts resulting from proposed activities.

  12. Land subsidence in major cities of Central Mexico: Interpreting InSAR-derived land subsidence mapping with hydrogeological data

    Science.gov (United States)

    Castellazzi, Pascal; Arroyo-Domínguez, Norma; Martel, Richard; Calderhead, Angus I.; Normand, Jonathan C. L.; Gárfias, Jaime; Rivera, Alfonso

    2016-05-01

    Significant structural damages to urban infrastructures caused by compaction of over-exploited aquifers are an important problem in Central Mexico. While the case of Mexico City has been well-documented, insight into land subsidence problems in other cities of Central Mexico is still limited. Among the cities concerned, we present and discuss the cases of five of them, located within the Trans-Mexican Volcanic Belt (TMVB): Toluca, Celaya, Aguascalientes, Morelia, and Queretaro. Applying the SBAS-InSAR method to C-Band RADARSAT-2 data, five high resolution ground motion time-series were produced to monitor the spatio-temporal variations of displacements and fracturing from 2012 to 2014. The study presents recent changes of land subsidence rates along with concordant geological and water data. It aims to provide suggestions to mitigate future damages to infrastructure and to assist in groundwater resources management. Aguascalientes, Celaya, Morelia and Queretaro (respectively in order of decreasing subsidence rates) are typical cases of fault-limited land subsidence of Central Mexico. It occurs as a result of groundwater over-exploitation in lacustrine and alluvial deposits covering highly variable bedrock topography, typical of horst-graben geological settings. Aguascalientes and Toluca show high rates of land subsidence (up to 10 cm/yr), while Celaya and Morelia show lower rates (from 2 to 5 cm/yr). Comparing these results with previous studies, it is inferred that the spatial patterns of land subsidence have changed in the city of Toluca. This change appears to be mainly controlled by the spatial heterogeneity of compressible sediments since no noticeable change occurred in groundwater extraction and related drawdown rates. While land subsidence of up to 8 cm/yr has been reported in the Queretaro Valley before 2011, rates inferior to 1 cm/yr are measured in 2013-2014. The subsidence has been almost entirely mitigated by major changes in the water management

  13. Structural Vulnerability among Migrating Women and Children Fleeing Central America and Mexico:The Public Health Impact of Humanitarian Parole

    Directory of Open Access Journals (Sweden)

    Elizabeth Salerno Valdez

    2015-06-01

    Full Text Available Since October 2013, US Customs and Border Patrol (USCBP has apprehended 15,979 families on the Southwest Border of the United States. Daily, migrating women and children from Mexico and Central America that qualify for humanitarian parole are released from immigration detention to a humanitarian aid organization in Southern Arizona. After several days in detention facilities, these families arrive tired, hungry, dehydrated, and with minimal direction regarding their final destination, and adherence to the parameters of their parole. Project Helping Hands (PHH utilizes a network of volunteers to provide the women and children with food, water, clothing, hygiene products, hospitality, and legal orientation. The aim of this assessment was to document the experiences of families granted humanitarian parole through the lens of structural vulnerability. Here we apply qualitative methods to elicit PHH lead volunteer perspectives regarding the migration experience of migrating families. Using inductive analysis, we found six major themes emerged from the qualitative data: reasons for leaving, experience on the journey, dehumanization in detention, family separation, vulnerability, and resiliency.These findings elucidate the different physical and psychological distresses that migrating families from Mexico and Central America experience before, during and after their arrival at the US-Mexico border. We posit that these distresses are a result of, or exacerbated by, structural vulnerability. Structural vulnerability has life-long health implications for a sub-population of young mothers and their children. The number of migrating families who have experienced traumatic events before, and during their migration experience continues to expand and thus warrants consideration of mental health surveillance and intervention efforts for these families. More public health research is needed to better understand and combat the health challenges of this growing

  14. Structural Vulnerability Among Migrating Women and Children Fleeing Central America and Mexico: The Public Health Impact of "Humanitarian Parole".

    Science.gov (United States)

    Valdez, Elizabeth Salerno; Valdez, Luis A; Sabo, Samantha

    2015-01-01

    Since October 2013, US Customs and Border Patrol has apprehended 15,979 families on the Southwest Border of the US. Daily, migrating women and children from Mexico and Central America that qualify for humanitarian parole are released from immigration detention to a humanitarian aid organization in Southern Arizona. After several days in detention facilities, these families arrive tired, hungry, dehydrated, and with minimal direction regarding their final destination, and adherence to the parameters of their parole. Project helping hands (PHHs) utilizes a network of volunteers to provide the women and children with food, water, clothing, hygiene products, hospitality, and legal orientation. The aim of this assessment was to document the experiences of families granted humanitarian parole through the lens of structural vulnerability. Here, we apply qualitative methods to elicit PHH lead volunteer perspectives regarding the migration experience of migrating families. Using inductive analysis, we found six major themes emerged from the qualitative data: reasons for leaving, experience on the journey, dehumanization in detention, family separation, vulnerability, and resiliency. These findings elucidate the different physical and psychological distresses that migrating families from Mexico and Central America experience before, during and after their arrival at the US-Mexico border. We posit that these distresses are a result of, or exacerbated by, structural vulnerability. Structural vulnerability has life-long health implications for a sub-population of young mothers and their children. The number of migrating families who have experienced traumatic events before and during their migration experience continues to expand and thus warrants consideration of mental health surveillance and intervention efforts for these families. More public health research is needed to better understand and combat the health challenges of this growing population.

  15. Reflections on Critical Incidents of EFL Teachers during Career Entry in Central Mexico

    Science.gov (United States)

    Lengeling, M. Martha; Mora Pablo, Irasema

    2016-01-01

    This article explores the reflections of critical incidents of eight beginning English as a foreign language teachers and one of their trainers in Mexico. Based upon narrative inquiry and through the use of journals, critical incidents and how they have impacted beginning teachers in their thinking were specifically looked at. From the data we…

  16. Four new species of Cymatodera Gray from central and southern Mexico (Coleoptera, Cleridae, Tillinae

    Directory of Open Access Journals (Sweden)

    Alan F. Burke

    2015-07-01

    Full Text Available Four new species of Cymatodera are described from Mexico: C. tortuosa Burke & Rifkind, sp. n. from Hidalgo and Tamaulipas; C. ortegae Burke, sp. n. from Colima, Jalisco and Michoacan; C. gerstmeieri Burke & Rifkind, sp. n. from Chiapas; and C. mixteca Burke & Rifkind, sp. n. from Puebla and Guerrero. Male genitalia and other characters of taxonomic value are illustrated.

  17. Four new species of Cymatodera Gray from central and southern Mexico (Coleoptera, Cleridae, Tillinae)

    Science.gov (United States)

    Burke, Alan F.; Rifkind, Jacques; Zolnerowich, Gregory

    2015-01-01

    Abstract Four new species of Cymatodera are described from Mexico: Cymatodera tortuosa Burke & Rifkind, sp. n. from Hidalgo and Tamaulipas; Cymatodera ortegae Burke, sp. n. from Colima, Jalisco and Michoacan; Cymatodera gerstmeieri Burke & Rifkind, sp. n. from Chiapas; and Cymatodera mixteca Burke & Rifkind, sp. n. from Puebla and Guerrero. Male genitalia and other characters of taxonomic value are illustrated. PMID:26257571

  18. Assessment of the sustainability of dual-purpose farms by the IDEA method in the subtropical area of central Mexico.

    Science.gov (United States)

    Salas-Reyes, Isela Guadalupe; Arriaga-Jordán, Carlos Manuel; Rebollar-Rebollar, Samuel; García-Martínez, Anastacio; Albarrán-Portillo, Benito

    2015-08-01

    The objective of this study was to assess the sustainability of 10 dual-purpose cattle farms in a subtropical area of central Mexico. The IDEA method (Indicateurs de Durabilité des Exploitations Agricoles) was applied, which includes the agroecological, socio-territorial and economic scales (scores from 0 to 100 points per scale). A sample of 47 farms from a total of 91 registered in the local livestock growers association was analysed with principal component analysis and cluster analysis. From results, 10 farms were selected for the in-depth study herein reported, being the selection criterion continuous milk production throughout the year. Farms had a score of 88 and 86 points for the agroecological scale in the rainy and dry seasons. In the socio-territorial scale, scores were 73 points for both seasons, being the component of employment and services the strongest. Scores for the economic scale were 64 and 56 points for the rainy and dry seasons, respectively, when no economic cost for family labour is charged, which decreases to 59 and 45 points when an opportunity cost for family labour is considered. Dual-purpose farms in the subtropical area of central Mexico have a medium sustainability, with the economic scale being the limiting factor, and an area of opportunity.

  19. The cultural and chronological context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexico.

    Science.gov (United States)

    Ranere, Anthony J; Piperno, Dolores R; Holst, Irene; Dickau, Ruth; Iriarte, José

    2009-03-31

    Molecular evidence indicates that the wild ancestor of maize is presently native to the seasonally dry tropical forest of the Central Balsas watershed in southwestern Mexico. We report here on archaeological investigations in a region of the Central Balsas located near the Iguala Valley in Guerrero state that show for the first time a long sequence of human occupation and plant exploitation reaching back to the early Holocene. One of the sites excavated, the Xihuatoxtla Shelter, contains well-stratified deposits and a stone tool assemblage of bifacially flaked points, simple flake tools, and numerous handstones and milling stone bases radiocarbon dated to at least 8700 calendrical years B.P. As reported in a companion paper (Piperno DR, et al., in this issue of PNAS), starch grain and phytolith residues from the ground and chipped stone tools, plus phytoliths from directly associated sediments, provide evidence for maize (Zea mays L.) and domesticated squash (Cucurbita spp.) in contexts contemporaneous with and stratigraphically below the 8700 calendrical years B.P. date. The radiocarbon determinations, stratigraphic integrity of Xihuatoxtla's deposits, and characteristics of the stone tool assemblages associated with the maize and squash remains all indicate that these plants were early Holocene domesticates. Early agriculture in this region of Mexico appears to have involved small groups of cultivators who were shifting their settlements seasonally and engaging in a variety of subsistence pursuits.

  20. Age of the Xalnene Ash, Central Mexico: A Rock Magnetic Perspective

    Science.gov (United States)

    Feinberg, J. M.; Renne, P. R.; Waters, M. R.; Arroyo-Cabrales, J.; Ochoa-Castillo, P.; Perez-Campo, M.

    2007-05-01

    Features interpreted as human footprints ~40 ka old have been reported from the Toluquilla quarry near Valsequillo Reservoir, 15 km south of the city of Puebla in central Mexico (Gonzalez et al., 2006). The indentations were found in an indurated basaltic lapilli tuff informally known as the Xalnene Ash. The ~40 ka age of the tuff was based on optically stimulated luminescence (OSL) analysis of baked quartz-rich materials incorporated into the ash during eruption. If true, this ~40 ka age suggests that humans migrated into the Americas at a far earlier time than is currently believed. In contrast to the conclusions of Gonzalez et al. (2006), the age of the Xalnene ash was determined as 1.30 ± 0.03 Ma (2σ) based on highly reproducible 40Ar/39Ar analyses of homogenous basaltic lapilli (Renne et al., 2005). This age is further supported by paleomagnetic data, which shows a reversed polarity for the Xalnene Ash, consistent with deposition during chron C1r.2r (1.77 to 1.07 Ma). The magnetic mineralogy within the Xalnene Ash is not straightforward, and is a reflection of its volcanic origin modified by its subsequent hydrous alteration via prolonged exposure to varying water levels in Lake Valsequillo. Submicron titanomagnetite grains occur within the cores of the lapilli and are characterized by Curie temperatures between 400-500 °C corresponding to unoxidized compositions ranging from Fe2.82Ti0.18O4 to Fe2.68Ti0.32O4. Two components of magnetization were revealed during progressive alternating field (AF) demagnetization of oriented, individual lapilli: a low coercivity, reversed component that is typically removed after 15-20 mT, and a randomly oriented, but well-defined, higher coercivity component. The directions associated with the low coercivity component are consistent with the direction of the bulk rock characteristic remanent magnetization. This low coercivity component may have been acquired immediately after deposition during the final stages of cooling, or

  1. Centrality of Event across Cultures. Emotionally Positive and Negative Events in Mexico, China, Greenland, and Denmark

    DEFF Research Database (Denmark)

    Zaragoza Scherman, Alejandra; Berntsen, Dorthe

    During their lifetime, people experience both emotionally positive and negative events. The Centrality of Event Scale (CES; Berntsen and Rubin, 2006; Berntsen, Rubin and Siegler, 2011) measures the extent to which an event is central to someone’s identity and life story. An event becomes central ...

  2. Evolución tectónica, paleogeográfica y metalogénica durante el Cenozoico en los Andes de Chile norte y central e implicaciones para las regiones adyacentes de Bolivia y Argentina Tectonic, paleogeographic, and metallogenic evolution during the Cenozoic in the Andes of Central and Northern Chile and implication for the adjacent regions of Bolivia and Argentina

    Directory of Open Access Journals (Sweden)

    Reynaldo Charrier

    2009-10-01

    Full Text Available La orogenia incaica dio origen a un importante relieve en el Eoceno Medio, el que se concentró en el ámbito del arco magmático precedente, la Cordillera Incaica. Este relieve positivo de orientación NNE se extendió desde el sur de Perú hasta la región central de Chile y separó dos dominios paleogeográficos que tuvieron evoluciones diferentes durante el resto del Cenozoico. El dominio occidental se caracterizó por el predominio de procesos de erosión y sedimentación. En el dominio oriental también existieron importantes episodios de erosión que originaron depósitos que se encuentran en la vertiente oriental de la cadena en la actualidad y presentan una cronología comparable con la de los depósitos del dominio occidental. Sin embargo, la evolución se caracterizó por presentar, a partir del Eoceno Tardío, diferencias al norte y sur de los ~27ºS. Al norte de esa latitud, en el ámbito del Altiplano-Puna, el arco magmático se mantuvo aproximadamente en la misma posición, coincidente con la del arco actual, y estuvo bordeado por una cuenca de antepaís de retroarco; mientras que, al sur de ~27ºS, se desarrollaron sucesivos arcos magmáticos con una marcada migración hacia el este. El arco magmático del Eoceno Tardío al Oligoceno Tardío - Mioceno Temprano se caracterizó por el desarrollo de una amplia cuenca extensional de intra-arco, la cuenca de Abanico. En esta cuenca se acumularon hasta 3.000 m de rocas volcánicas, volcaniclásticas y, subordinadamente, sedimentarias. A partir del límite oligoceno-mioceno, tuvo lugar un nuevo evento compresivo a lo largo de todo el orógeno que rejuveneció el núcleo de la Cordillera Incaica e invirtió la cuenca de Abanico permitiendo la generación de abundantes depósitos sintectónicos a ambos lados de los nuevos relieves. El inicio de este evento coincide con la orogenia pehuenche, los pulsos compresivos se mantuvieron hasta el Plioceno Temprano. En el Mioceno Temprano a Medio

  3. The ~ 2000 yr BP Jumento volcano, one of the youngest edifices of the Chichinautzin Volcanic Field, Central Mexico

    Science.gov (United States)

    Arce, J. L.; Muñoz-Salinas, E.; Castillo, M.; Salinas, I.

    2015-12-01

    The Chichinautzin Volcanic Field is situated at the southern limit of the Basin of Mexico and the Metropolitan area of Mexico City, the third most populated city around the world. The Chichinautzin Volcanic field holds more than 220 monogenetic volcanoes. Xitle is the youngest of these with an estimated age of 1.6 ky BP. Xitle's eruptive activity took place during the Mesoamerican Mexican Pre-classic period and is related to the destruction of Cuicuilco Archaeological Site, the oldest civilization known in Central Mexico. However, there are still several regional cones that have not been dated. Based on 14C ages, stratigraphic and geomorphologic criteria, we conclude that the Jumento volcano, located to the west of Xitle, is one of the youngest cones of the Chichinautzin Volcanic Field. The Jumento volcano has a basaltic andesite composition, and its eruptive activity was initially hydromagmatic, followed by Strombolian and finally effusive events occurred recorded through: (1) a sequence of hydromagmatic pyroclastic surges and ashfall layers emplaced at a radius of > 5 km from the crater with charcoal fragments at its base; this activity built the Jumento's cone with slopes of 32°; and (2) lava flows that breached the southern part of the cone and flowed for up to 2.5 km from the vent. The resulting 14C ages for this volcano yielded a maximum age of ~ 2 ky BP. Morphometric analysis indicates that the state of degradation of Jumento cone is similar to the Xitle, suggesting that the Jumento could be in the state of degradation of a volcanic structure of similar age or younger adding credence to the probable radiocarbon age of ~ 2 ky BP for the Jumento edifice.

  4. Population Genetics of Overwintering Monarch Butterflies, Danaus plexippus (Linnaeus), from Central Mexico Inferred from Mitochondrial DNA and Microsatellite Markers.

    Science.gov (United States)

    Pfeiler, Edward; Nazario-Yepiz, Nestor O; Pérez-Gálvez, Fernan; Chávez-Mora, Cristina Alejandra; Laclette, Mariana Ramírez Loustalot; Rendón-Salinas, Eduardo; Markow, Therese Ann

    2016-10-03

    Population genetic variation and demographic history in Danaus plexippus (L.), from Mexico were assessed based on analyses of mitochondrial cytochrome c oxidase subunit I (COI; 658 bp) and subunit II (COII; 503 bp) gene segments and 7 microsatellite loci. The sample of 133 individuals included both migratory monarchs, mainly from 4 overwintering sites within the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico (states of Michoacán and México), and a nonmigratory population from Irapuato, Guanajuato. Haplotype (h) and nucleotide (π) diversities were relatively low, averaging 0.466 and 0.00073, respectively, for COI, and 0.629 and 0.00245 for COII. Analysis of molecular variance of the COI data set, which included additional GenBank sequences from a nonmigratory Costa Rican population, showed significant population structure between Mexican migratory monarchs and nonmigratory monarchs from both Mexico and Costa Rica, suggesting limited gene flow between the 2 behaviorally distinct groups. Interestingly, while the COI haplotype frequencies of the nonmigratory populations differed from the migratory, they were similar to each other, despite the great physical distance between them. Microsatellite analyses, however, suggested a lack of structure between the 2 groups, possibly owing to the number of significant deviations from Hardy-Weinberg equilibrium resulting from heterzoygote deficiencies found for most of the loci. Estimates of demographic history of the combined migratory MBBR monarch population, based on the mismatch distribution and Bayesian skyline analyses of the concatenated COI and COII data set (n = 89) suggested a population expansion dating to the late Pleistocene (~35000-40000 years before present) followed by a stable effective female population size (N ef) of about 6 million over the last 10000 years.

  5. Paired Magmatic-Metallogenic Belts in Myanmar - an Andean Analogue?

    Science.gov (United States)

    Gardiner, Nicholas; Robb, Laurence; Searle, Michael; Morley, Christopher

    2015-04-01

    contrasting minerals endowment. The Mogok-Mandalay-Mergui (MMM) Belt hosts crustal-melt S-type granites with significant tin-tungsten mineralization, and contains the historically major tungsten deposit of Mawchi. The Wuntho-Popa Arc comprises I-type granites and granodiorites with porphyry-type copper-gold and epithermal gold mineralization, and includes the world-class Monywa copper mine. Recent U-Pb radiometric age dating has shown the potential for the two belts to be both active from the Late Cretaceous to Eocene. The spatial juxtaposition of these two sub-parallel belts, the implication of contemporary magmatism, and their distinct but consistent metallogenic endowment bears strong similarities to the metallogenic belts of the South American Cordillera. Here we investigate whether they together represent the magmatic and metallogenic expression of an Andean-type setting in Myanmar during the subduction of Neo-Tethys. In this analogue the Wuntho-Popa Arc represents a proximal I-type magmatic belt sited immediately above the eastwards-verging Neo-Tethys subduction zone. Exhibiting porphyry-type copper-gold and epithermal gold mineralization, this would therefore be the Myanmar equivalent of the Andean coastal copper belts. Conversely, the parallel MMM Belt, comprised of more distal crustal-melt S-type tin granites, would have an analogue in the Bolivian tin belt.

  6. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

    Science.gov (United States)

    Rebich, R.A.; Houston, N.A.; Mize, S.V.; Pearson, D.K.; Ging, P.B.; Evan, Hornig C.

    2011-01-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  7. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States.

    Science.gov (United States)

    Rebich, Richard A; Houston, Natalie A; Mize, Scott V; Pearson, Daniel K; Ging, Patricia B; Evan Hornig, C

    2011-10-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%).

  8. A new species of Cletocamptus Schmankewitsch, 1875 (Crustacea, Copepoda, Harpacticoida from a high altitude saline lake in Central Mexico

    Directory of Open Access Journals (Sweden)

    Eduardo Suarez Morales

    2013-04-01

    Full Text Available During the analysis of littoral samples collected from a high-altitude saline crater lake in Central Mexico, several female and male specimens of harpacticoid copepods were recovered and taxonomically examined. They were found to represent an undescribed species of the canthocamptid genus Cletocamptus Schmankewitsch, 1875. The new species, C. gomezi n. sp. is described herein based on specimens of both sexes. It resembles C. stimpsoni Gómez, Fleeger, Rocha-Olivares and Foltz, 2004 from Louisiana but also C. trichotus Kiefer, 1929. The new species differs from C. stimpsoni and from other congeners by details of the maxillular armature, the setation of the endopodal segments of legs 2 and 3, and the armature of the third exopodal segment of legs 3 and 4. Also, the dorsal (VII and the outer (IV caudal setae are both relatively shorter than in C. stimpsoni. This is the second species of the genus known to be distributed in Mexico. The occurrence of the new species in a high-altitude saline lake, the isolation of the type locality, and its absence from adjacent freshwater lakes suggest that this species is endemic to this site.

  9. Presence of nonylphenol ethoxylate surfactants in a watershed in central Mexico and removal from domestic sewage in a treatment wetland.

    Science.gov (United States)

    Belmont, Marco A; Ikonomou, Michael; Metcalfe, Chris D

    2006-01-01

    The Texcoco River in central Mexico is polluted with domestic wastewater as a result of discharges of untreated or inadequately treated sewage. Since nonylphenol ethoxylate (NPEO) surfactants and their intermediate degradation products such as nonylphenol (NP) and NP mono- and diethoxylate (NP1EO, NP2EO) have been found in domestic wastewater and in surface waters near wastewater discharges in industrialized countries, the Texcoco River was sampled to determine whether these compounds were present. The results indicated that NPEOs were present at very high concentrations (> 100 microg/L) in the lower reaches of the Texcoco River, but unlike rivers in industrialized countries, relatively low concentrations of intermediate degradation products, including NP1EO, NP2EO, and NP, were present. The presence and fate of NPEOs compounds in wastewater treatment plants have been studied only in conventional treatment systems in industrialized countries. In this study, the fate of these compounds was studied in a pilot-scale treatment wetland constructed in the small community of Santa Maria Nativitas in the Texcoco River watershed. The treatment wetland removed > 75% of NPEOs from the domestic wastewater, but the greatest proportion of removal occurred in parts of the treatment wetland where sedimentation existed. This is the first report of NPEO compounds in the water resources of a developing country. These data indicate that construction of low-cost and technologically simple treatment wetlands may be one solution to reducing the impacts of contaminants from domestic sewage in developing countries, such as Mexico.

  10. The Precambrian Structure of the Estancia Basin, Central New Mexico: New Seismic Images of the Mazatzal Province

    Science.gov (United States)

    Elebiju, O. O.; Miller, K. C.; Andronicos, C. L.

    2004-12-01

    The Estancia Basin, located between the Manzano Mountains and Pedernal Hills, in central New Mexico, provides an excellent location for studying the effects of Proterozoic structural grain on subsequent Phanerozoic tectonic events. The Estancia Basin lies within the Proterozoic Mazatzal province. In recent years, the National Science Foundation Continental Dynamics Program within the Rocky Mountains Project, (CD-ROM) group has been examining the boundary between the two broad northeast-trending tectonically-mixed Paleoproterozoic terranes in New Mexico: the Yavapai province to the north and the Mazatzal province to the south. Reflection data collected as part of the CD-ROM effort image a portion of the Mazatzal province at a location 100 km east of the Estancia Basin. In an effort to contribute to a deeper understanding of the CD-ROM seismic image and regional Precambrian geology, we are analyzing ten seismic reflection profiles, well-logs, magnetic and gravity data from the Estancia basin area. The seismic data show numerous dipping reflections within the Precambrian basement that may represent prominent Precambrian ductile shear zones similar to those exposed in the adjacent Manzano Mountains and Pedernal Hills. An earlier study that focused on the Paleozoic evolution of the Estancia Basin, by Barrow and Keller (1994) also noted these same reflectors and that a prominent gravity low observed in the vicinity of the basin could not be fully explained by the Paleozoic geology. We present a new interpretation of these data.

  11. Hantavirus testing in rodents of north-central New Mexico 1993-1995

    Energy Technology Data Exchange (ETDEWEB)

    Biggs, J.; Bennett, K.; Salisbury, M. [and others

    1996-03-01

    In 1993, an outbreak of a new strain of hantavirus in the southwestern US indicated that deer mice (Peromyscus maniculatus) was the primary carrier of the virus. In 1993, 1994, and 1995 the Ecological Studies Team (EST) at Los Alamos National Laboratory surveyed small mammal populations using live capture-recapture methods in Los Alamos County, New Mexico, to determine seroprevalence of hantavirus in this region. EST used trapping grids in 1993 and 1994 and used trapping webs in 1995. Grids were 120 m x 120 m (400 ft x 400 ft) with 144 trap stations at each grid. Three webs consisting of 148 traps each were used in 1995. Trapping took place over 4 to 8 consecutive nights. Programs CAPTURE and Distance were used to determine density estimates for grids and webs, respectively. Blood samples were analyzed in 1993 by the Centers for Disease Control and the University of New Mexico, School of Medicine. The 1994 and 1995 samples were analyzed by the University of New Mexico, School of Medicine. The deer mouse (Peromyscus maniculatus) was the most commonly captured species at all locations except one site where voles (Microtus spp.) were the most commonly captured species. Other species sampled included: harvest mice (Reithrodontomys megalotis), woodrats (Neotoma spp.), shrews (Sorex spp.), white-footed mice (Peromyscus leucopus), pinyon mice (Peromyscus trueii), and brush mouse (Peromyscus boylii). Results of the 1993, 1994, and 1995 testing identified a total overall seroprevalence rate among deer mice of approximately 5.5%, 4.2%, and 0%, respectively. Several other species tested positive for the hantavirus but it is uncertain if it is Sin Nombre virus. Further studies will be necessary to quantify seroprevalence rates in those species. Higher seroprevalence rates were found in males than females. Seroprevalence rates for Los Alamos County were much lower than elsewhere in the region.

  12. School-Age Children Obesity in Rural Communities with International Migration in Central Mexico.

    OpenAIRE

    Carmona González, Maricela; Viczcarra Bordi., Ivonne

    2009-01-01

    The objective of the study was to evaluate the prevalence of obesity in school children between 6 and 12 years old. The study was carried out in communities with international migration tradition in the south of the Mexico state. Changes on food habits and life style were also evaluated. The Index of Corporal Mass (ICM) of 276 students was recorded. The 276 students were divided into two groups according to migrant or non-migrant father and by gender to identify differences between groups. Pa...

  13. Evidence from Central Mexico Supporting the Younger Dryas Extraterrestrial Impact Hypothesis

    Science.gov (United States)

    2012-03-05

    Steven M. Stanley, University of Hawaii , Honolulu, HI, and approved January 31, 2012 (received for review July 13, 2011) We report the discovery in...second largest lake in Mexico, located at high elevation of 1,820 m in the northern part of the state of Michoacán within the tectonically active...and Fe, concentrated in the rind. They reach a significant peak of approximately 680∕kg at 2.75 m within the YDB layer. Above 2.75 m, the CSp persist

  14. Economic and financial viability of small-scale dairy systems in central Mexico: economic scenario 2010-2018.

    Science.gov (United States)

    Posadas-Domínguez, R R; Callejas-Juárez, N; Arriaga-Jordán, C M; Martínez-Castañeda, F E

    2016-12-01

    A simulation Monte Carlo model was used to assess the economic and financial viability of 130 small-scale dairy farms in central Mexico, through a Representative Small-Scale Dairy Farm. Net yields were calculated for a 9-year planning horizon by means of simulated values for the distribution of input and product prices taking 2010 as base year and considering four scenarios which were compared against the scenario of actual production. The other scenarios were (1) total hiring in of needed labour; (2) external purchase of 100 % of inputs and (3) withdrawal of subsidies to production. A stochastic modelling approach was followed to determine the scenario with the highest economic and financial viability. Results show a viable economic and financial situation for the real production scenario, as well as the scenarios for total hiring of labour and of withdrawal of subsidies, but the scenario when 100 % of feed inputs for the herd are bought-in was not viable.

  15. Reproduction and survival under different water temperatures of Gyrodactylus mexicanus (Platyhelminthes: Monogenea), a parasite of Girardinichthys multiradiatus in Central Mexico.

    Science.gov (United States)

    Sereno-Uribe, Ana L; Zambrano, Luis; García-Varela, Martín

    2012-12-01

    Gyrodactylid population growth may depend on abiotic variables such as temperature. We tested the survival and reproductive rate of Gyrodactylus mexicanus, a parasite infecting fins of Girardinichthys multiradiatus, at 3 different water temperatures, 10-13, 19-22, and 24 C. The temporal sequence of birth and age at death of each parasite isolated from the hosts was recorded through at least 8 generations. Our results showed that the average number of offspring per parasite was 2.0 when averaged across all temperatures. However, the generation time was negatively correlated with temperature. The innate capacity for increase (r(m)) was positively correlated with water temperature: from 0.29 parasite/day at 13 C to 0.48 parasite/day at 24 C. These data confirm that water temperature has a direct influence on parasite population dynamics. The current study represents the first contribution to understanding the population ecology of the monogenean G. mexicanus in central Mexico.

  16. The population structure of Phytophthora infestans from the Toluca Valley of Central Mexico suggests genetic differentiation between populations from cultivated potato and wild Solanum spp.

    NARCIS (Netherlands)

    Flier, W.G.; Grünwald, N.J.; Kroon, L.P.N.M.; Sturbaum, A.K.; Bosch, van den G.B.M.; Garay-Serrano, E.; Lozoya-Saldaña, H.; Fry, W.E.; Turkensteen, L.J.

    2003-01-01

    The Population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected front cultivated potatoes and the native wild Solanum spp., S. demissum and S. xedinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplifi

  17. Coyotes, Concessions and Construction Companies: Illegal Water Markets and Legally Constructed Water Scarcity in Central Mexico

    Directory of Open Access Journals (Sweden)

    Nadine Reis

    2014-10-01

    Full Text Available Many regions of (semiarid Mexico, such as the Valley of Toluca, face challenges due to rapid growth and the simultaneous overexploitation of groundwater. The water reform of the 1990s introduced individual water rights concessions granted through the National Water Commission (Comisión Nacional del Agua, or CONAGUA. Since then, acquiring new water rights in officially 'water-scarce' aquifers is only possible through official rights transmissions from users ceding their rights. With the law prohibiting the sale of water rights, a profitable illegal market for these rights has emerged. The key actor in the water rights allocation network is the coyote, functioning as a broker between a people wanting to cede water rights and those needing them, and b the formal and informal spheres of water rights allocation. Actors benefitting from water rights trading include the coyote and his 'working brigades', water users selling surplus rights, and (senior and lower-level staff in the water bureaucracy. The paper concludes that legally constructed water scarcity is key to the reproduction of illegal water rights trading. This has important implications regarding the current push for expanding regularisation of groundwater extraction in Mexico. Currently, regularisation does not counter overexploitation, while possibly leading to a de facto privatisation of groundwater.

  18. A new species of Torrestrongylus (Trichostrongylidae, Anoplostrongylinae) from Macrotus waterhousii (Chiroptera: Phyllostomidae) in Central Mexico.

    Science.gov (United States)

    Caspeta-Mandujano, Juan Manuel; Peralta-Rodríguez, Jorge Luis; Galindo-García, María Guadalupe; Jiménez, Francisco Agustín

    2015-01-01

    A new species of nematode, Torrestrongylus tetradorsalis n. sp., is described herein, based on specimens recovered from the small intestine of the leaf-nosed bat, Macrotus waterhousii, from the Biosphere Reserve "Sierra de Huautla" in the state of Morelos, Mexico. The new species is included in Torrestrongylus because it features a bursa of the type 3 - 2, a divided cephalic vesicle with an anterior half in the shape of an umbrella, and a posterior widened half. The new species can be distinguished from the only other congener T. torrei Pérez-Vigueras, 1935 by four key features: first, by the absence of cervical alae in both males and females; second, by the relatively longer second half of the cephalic cap; third, by the configuration of the dorsal ray, that does not have a medial terminal ray, and finally, by the structure of the spicules. This is the second species in the genus, previously known from bats of the families Phyllostomidae and Molossidae in Cuba, and now in Mexico.

  19. Metallogenic epoch and genesis of the gold deposits in Jiaodong Peninsula, Eastern China: a regional review

    Institute of Scientific and Technical Information of China (English)

    YANG Liqiang; DENG Jun; GE Liangsheng; WANG Qingfei; ZHANG Jing; GAO Bangfei; JIANG Shaoqing; XU Hao

    2007-01-01

    Gold deposits are characterized by multi-sources, superimposition, large scale and temporal-spatial concentration in Jiaodong Peninsula, Eastern China. In this paper, we review the history and the development of the study on metallogenic chronology and genesis of gold deposits, summarize the main features of superimposed metallogenesis, provide evidence of the Mesozoic complex metallogenic system, and point out some problems for further research of Jiaodong gold deposit cluster from a regional view. Although gold deposits are different in genetic types, ore-forming materials and geological settings, our research indicates that the accumulation and emplacement of the ore-forming materials are temporally-spatially concentrated on a large scale, and the main metallogenic epoch of Jiaodong gold deposits was concentrated in Mesozoic. Metallogenic chronology and geological-geochemical data indicate that there are two periods of gold mineralizations occurred in 130-110 Ma and 90-80 Ma respectively in Jiaodong ore cluster. The gold deposit cluster results from the superimposition of the polygenetic mineralization, and further study is needed to investigate the formation and evolution of the Mesozoic complex metallogenic system.

  20. Regional metallogenic structure based on aeromagnetic data in northern Chile

    Science.gov (United States)

    Zhu, Xiao-San; Lu, Min-Jie

    2016-12-01

    Chile is a very important country that forms part of the Andean metallogenic belts. The Atacama and Domeyko fault systems in northern Chile control the tectonic-magmatic activities that migrate eastward and the types of mineral resources. In this paper, we processed and interpreted aeromagnetic data from northern Chile using reduction to pole, upward field continuation, the second derivative calculation in the vertical direction, inclination angle calculation, and analytical signal amplitude analysis. We revealed the locations and planar distribution characteristics of the regional deep faults along the NNE and NS directions. Furthermore, we observed that the major reasons for the formation of the tectonic-magmatic rocks belts were the nearly parallel deep faults distributed from west to east and multiple magmatic activities along these faults. We ascertained the locations of volcanic mechanisms and the relationships between them using these regional deep faults. We deduced the spatial distributions of the basic-intermediate, basic, and acidic igneous rocks, intrusive rocks, and sedimentary sequences. We showed the linear positive magnetic anomalies and magnetic anomaly gradient zones by slowly varying the background, negative magnetic anomaly field, which indicated the presence of strong magmatic activities in these regional deep faults; it also revealed the favorable areas of copper and polymetallic mineralization. This study provides some basic information for further research on the geology, structural characteristics, and mineral resource prospecting in northern Chile.

  1. Centrality of Event across Cultures. Emotionally Positive and Negative Events in Mexico, China, Greenland, and Denmark.

    OpenAIRE

    Zaragoza Scherman, Alejandra; Berntsen, Dorthe

    2014-01-01

    During their lifetime, people experience both emotionally positive and negative events. The Centrality of Event Scale (CES; Berntsen and Rubin, 2006; Berntsen, Rubin and Siegler, 2011) measures the extent to which an event is central to someone’s identity and life story. An event becomes central when it is an important part of our identity and life story, when it changes the way we view the world in everyday life, and when we use it as a turning point in our life story. CES research has produ...

  2. Miocene sediment dispersal in the central Española basin, Rio Grande rift, New Mexico, U.S.A.

    Science.gov (United States)

    Cavazza, William

    1986-12-01

    The central Española basin in north-central New Mexico represents one of the best opportunities to examine deposits related to the development of the Rio Grande rift. The Miocene Tesuque Formation represents the bulk of the Española basin fill. It is composed of a 2000-2500 m thick sequence of alluvial-fluvial and, subordinately, lacustrine deposits with numerous interbedded ash-fall tuff layers. The overall detrital composition of the Tesuque Formation is very similar throughout the central Española basin. Provenance is primarily from basement uplifts composed of Precambrian igneous and high-grade metamorphic rocks. Nevertheless, the combined use of paleocurrent analysis, and sandstone and conglomerate petrology allows a detailed reconstruction of the sediment paleodispersal system. Two sedimentary provinces are present within the Tesuque Formation: Province A, present in the eastern, central and southern portions of the study area, has a predominantly plutoniclastic and metamorphiclastic composition, and shows systematic paleocurrents toward the west. The sediments were derived from the Precambrian-cored Santa Fe block of the Sangre de Cristo Mountains, located directly to the east of the study area. Province B, present only in the northwestern portion of the study area, is characterized by a minor but significant amount of volcaniclastic and sedimentaclastic detritus, and shows consistent SSW-directed paleocurrents. The source area was possibly located in the area of the Taos Plateau and Latir volcanic fields. An intermediate narrow and discontinuous belt (province A + B) represents a hybrid province, where directional and compositional parameters are gradational.

  3. Taxonomic and floristic novelties for Echeveria (Crassulaceae) in Central Michoacan, Mexico

    Science.gov (United States)

    García-Ruiz, Ignacio; Valentín-Martínez, Dagoberto; Carrillo-Reyes, Pablo; Costea, Mihai

    2016-01-01

    Abstract A new species, Echeveria coruana, is described and illustrated from the malpaís near San Andrés Corú, Michoacan, Mexico. The species belongs to series Gibbiflorae and the new taxon was compared with Echeveria purhepecha and Echeveria patriotica, with whom it shares the closest morphological affinities. Additionally, Echeveria yalmanantlaensis an endangered species from Sierra of Manantlán Biosphere Reserve, State of Colima, was also discovered near San Andrés Corú and is reported for the first time from the State of Michoacan. The conservation status of both species was (re)evaluated according to the criteria of the International Union for Conservation of Nature.

  4. Reinterpretation of the stratigraphy and structure of the Rancho Las Norias area, central Sonora, Mexico

    Science.gov (United States)

    Page, W.R.; Harris, A.G.; Poole, F.G.; Repetski, J.E.

    2003-01-01

    New geologic mapping and fossil data in the vicinity of Rancho Las Norias, 30 km east of Hermosillo, Sonora, Mexico, show that rocks previously mapped as Precambrian instead are Paleozoic. Previous geologic maps of the Rancho Las Norias area show northeast-directed, southwest-dipping reverse or thrust faults deforming both Precambrian and Paleozoic rocks. The revised stratigraphy requires reinterpretation of some of these faults as high-angle normal or oblique-slip faults and the elimination of other faults. We agree with earlier geologic map interpretations that compressional structures have affected the Paleozoic rocks in the area, but our mapping suggests that the direction of compression is from southeast to northwest. Published by Elsevier Ltd.

  5. Reflections on Critical Incidents of EFL Teachers During Career Entry in Central Mexico

    Directory of Open Access Journals (Sweden)

    M. Martha Lengeling

    2016-10-01

    Full Text Available This article explores the reflections of critical incidents of eight beginning English as a foreign language teachers and one of their trainers in Mexico. Based upon narrative inquiry and through the use of journals, critical incidents and how they have impacted beginning teachers in their thinking were specifically looked at. From the data we found seven emerging themes which basically revolve around the relationships that are established between the teacher and the students, the emerging professional identities of the beginning teachers, and the tutor’s reflection on knowledge transfer. Results showed how these teachers reflected upon their teaching practice and how the critical incidents helped them to analyze and evaluate their teaching process.

  6. [Parasites of the Central American tapir Tapirus bairdii (Perissodactyla: Tapiridae) in Chiapas, Mexico].

    Science.gov (United States)

    Cruz Aldán, Epigmenio; Lira Torres, Iván; Güiris Andrade, Dario Marcelino; Osorio Sarabia, David; Quintero M, Ma Teresa

    2006-06-01

    We analyzed 19 samples of Baird's tapir feces from La Sepultura Biosphere Reserve, collected between March and July 1999. We also took samples directly from a male tapir captured at the Montes Azules Biosphere Reserve. Both reserves are in Chiapas, Mexico. We used five techniques: flotation, MacMaster, micrometric, Ritchie's sedimentation and Ferreira's quantitative. In addition, we collected ectoparasites from animals captured in both reserves and from a captive couple from Tuxtla Gutierrez, Chiapas. These nematodes and protozoans were found: Agriostomun sp., Lacandoria sp., Neomurshidia sp., Trichostrongylus sp., Strongylus sp., Brachylumus sp, and an unidentified species of ancilostomaide. We also found Eimeria sp. and Balantidium coli, as well as the mites Dermacentor halli, Dermacentor latus, Amblyomma cajannense, Amblyomma coelebs, Amblyomma ovale, Anocentor nitens and Ixodes bicornis.

  7. Used battery collection in central Mexico: metal content, legislative/management situation and statistical analysis.

    Science.gov (United States)

    Guevara-García, José Antonio; Montiel-Corona, Virginia

    2012-03-01

    A statistical analysis of a used battery collection campaign in the state of Tlaxcala, Mexico, is presented. This included a study of the metal composition of spent batteries from formal and informal markets, and a critical discussion about the management of spent batteries in Mexico with respect to legislation. A six-month collection campaign was statistically analyzed: 77% of the battery types were "AA" and 30% of the batteries were from the informal market. A substantial percentage (36%) of batteries had residual voltage in the range 1.2-1.4 V, and 70% had more than 1.0 V; this may reflect underutilization. Metal content analysis and recovery experiments were performed with the five formal and four more frequent informal trademarks. The analysis of Hg, Cd and Pb showed there is no significant difference in content between formal and informal commercialized batteries. All of the analyzed trademarks were under the permissible limit levels of the proposed Mexican Official Norm (NOM) NMX-AA-104-SCFI-2006 and would be classified as not dangerous residues (can be thrown to the domestic rubbish); however, compared with the EU directive 2006/66/EC, 8 out of 9 of the selected battery trademarks would be rejected, since the Mexican Norm content limit is 20, 7.5 and 5 fold higher in Hg, Cd and Pb, respectively, than the EU directive. These results outline the necessity for better regulatory criteria in the proposed Mexican NOM in order to minimize the impact on human health and the environment of this type of residues.

  8. The transition between shortening and extensional regimes in central Mexico recorded in the tourmaline veins of the Comanja Granite

    Science.gov (United States)

    Angeles-Moreno, Edgar; Nieto-Samaniego, Angel Francisco; Ruiz-González, Francisco Jesús; Levresse, Gilles; Alaniz-Alvarez, Susana Alicia; Olmos Moya, María de Jesús Paulina; Xu, Shunshan; Miranda-Avilés, Raúl

    2017-01-01

    In central Mexico, there is a major angular unconformity separating two lithologic groups. Below the unconformity, the rocks display shortening deformation structures produced by the Laramide orogeny, overprinting those shortening structures there are normal faults related to the Cenozoic Basin and Range tectonics. Above the unconformity, the rocks are affected only by the Basin and Range tectonics, displaying mainly normal faults and in minor amount, lateral-oblique faults. We analyzed the Comanja Granite in the Sierra de Guanajuato, it is a large pluton that contains tourmaline veins. The Granite lacks of the shortening structures that pervasively affected the Mesozoic host-rocks; for this reason, we infer that the granite was formed after the main shortening event. We determined that the emplacement of the Comanja Granite took place between 51.0 ± 0.3 Ma and 49.5 ± 0.8 Ma, and that the tourmaline veins of the granite were formed at ∼51.0 Ma. At the microscopic scale, the tourmaline veins contain three kinds of tourmaline, called T1, T2, and T3, according to the order of their formation. The T1 tourmalines are brown colored and appear affected by brittle-ductile (D1) and brittle (D2) deformations. The cataclasites formed during D2 overprinted the brittle-ductile structures of D1, indicating the transition from deeper to shallower levels. In contrast, T2 and T3 tourmalines were not involved in those deformations. At the outcrop scale, we identified two slickensides in the tourmaline veins. The older, related to D1, is strike-slip with a small thrust component and the younger, related to D2, is normal with oblique components. The T1 tourmalines (which are deformed) were formed before the lateral-thrust faulting, whereas the T2 and T3 tourmalines, which are not deformed, were deposited after the faulting occurred in the veins. Our interpretation is that T1 tourmalines were deposited in the later phases of the Comanja Granite emplacement, with the minimum

  9. Modeling, simulation and analysis of a securities settlement system: the case of Central Securities Depository of Mexico

    Directory of Open Access Journals (Sweden)

    David F. Muñoz

    2012-12-01

    Full Text Available The Instituto para el Depósito de Valores (INDEVAL is the Central Securities Depository of Mexico. It is the only Mexican institution authorized to perform, in an integrated manner, the activities of safe-keeping, custody, management, clearing, settlement and transfer of securities. In this article, we report the modeling, simulation and analysis of a new Securities Settlement System (SSS implemented by INDEVAL, as part of a project for the implementation of a safer and more efficient operating system. The main objective of this research was to use reduced amounts of cash and securities, within reasonable periods of time, for the settlement of securities of the Mexican market. A linear programming model for the netting and clearing of operations was used. The performance of the new SSS was evaluated by performing experiments using a deterministic simulation model under different operation parameters, such as the number and monetary value of transactions, the time between clearing cycles and also under a new set of rules for pre-settlement operations. The results presented may be used by other Central Securities Depositories to make decisions related to the efficient and safer use of their resources. The implementation of the model took more than three years. Now many transactions that would remain pending if processed individually are settled together, thus reducing liquidity requirements dramatically -by 52% in cash and 26% in securities.

  10. Chemical and nutritional composition of tejate, a traditional maize and cacao beverage from the Central Valleys of Oaxaca, Mexico.

    Science.gov (United States)

    Sotelo, Angela; Soleri, Daniela; Wacher, Carmen; Sánchez-Chinchillas, Argelia; Argote, Rosa Maria

    2012-06-01

    Foam-topped cacao and maize beverages have a long history in Mesoamerica. Tejate is such a beverage found primarily in the Zapotec region of the Central Valleys of Oaxaca, Mexico. Historically tejate has been ceremonially important but also as an essential staple, especially during periods of hard fieldwork. However, the nutritional contribution of traditional foods such as tejate has not been investigated. We analyzed tejate samples from three Central Valley communities, vendors in urban Oaxaca markets and one migrant vendor in California, USA for their proximate composition, amino acid content and scores, and mineral and methylxanthine content. Nutritional and chemical variation exists among tejate recipes, however, the beverage is a source of energy, fat, methylxanthines, K, Fe and other minerals although their availability due to presence of phytates remains to be determined. Tejate is a source of protein comparable to an equal serving size of tortillas, with protein quality similarly limited in both. Tejate provides the nutritional benefits of maize, and some additional ones, in a form appealing during hot periods of intense work, and year round because of its cultural significance. Its substitution by sodas and other high glycemic beverages may have negative nutritional, health and cultural consequences.

  11. Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico

    Directory of Open Access Journals (Sweden)

    T. J. Christian

    2009-04-01

    Full Text Available In central Mexico during the spring of 2007 we measured the initial emissions of 12 gases and the aerosol speciation for elemental and organic carbon (EC, OC, anhydrosugars, Cl-, NO3-, and 20 metals from 10 cooking fires, four garbage fires, three brick making kilns, three charcoal making kilns, and two crop residue fires. Biofuel use has been estimated at over 2600 Tg/y. With several simple case studies we show that cooking fires can be a major, or the major, source of several gases and fine particles in developing countries. Insulated cook stoves with chimneys were earlier shown to reduce indoor air pollution and the fuel use per cooking task. We confirm that they also reduce the emissions of VOC pollutants per mass of fuel burned by about half. We did not detect HCN emissions from cooking fires in Mexico or Africa. Thus, if regional source attribution is based on HCN emissions typical for other types of biomass burning (BB, then biofuel use and total BB will be underestimated in much of the developing world. This is also significant because cooking fires are not detected from space. We estimate that 2000 Tg/y of garbage are generated and about half may be burned, making this a commonly overlooked major global source of emissions. We estimate a fine particle emission factor (EFPM2.5 for garbage burning of ~10±5 g/kg, which is in reasonable agreement with very limited previous work. We observe large HCl emission factors in the range 2–10 g/kg. Consideration of the Cl content of the global waste stream suggests that garbage burning may generate as much as 6–9 Tg/yr of HCl, which would make it a major source of this compound. HCl generated by garbage burning in dry environments may have a relatively greater atmospheric impact than HCl generated in humid areas. Garbage burning PM2.5 was found to contain levoglucosan and K in concentrations similar to those for biomass burning, so it could

  12. Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico

    Directory of Open Access Journals (Sweden)

    T. J. Christian

    2010-01-01

    Full Text Available In central Mexico during the spring of 2007 we measured the initial emissions of 12 gases and the aerosol speciation for elemental and organic carbon (EC, OC, anhydrosugars, Cl, NO3, and 20 metals from 10 cooking fires, four garbage fires, three brick making kilns, three charcoal making kilns, and two crop residue fires. Global biofuel use has been estimated at over 2600 Tg/y. With several simple case studies we show that cooking fires can be a major, or the major, source of several gases and fine particles in developing countries. Insulated cook stoves with chimneys were earlier shown to reduce indoor air pollution and the fuel use per cooking task. We confirm that they also reduce the emissions of VOC pollutants per mass of fuel burned by about half. We did not detect HCN emissions from cooking fires in Mexico or Africa. Thus, if regional source attribution is based on HCN emissions typical for other types of biomass burning (BB, then biofuel use and total BB will be underestimated in much of the developing world. This is also significant because cooking fires are not detected from space. We estimate that ~2000 Tg/y of garbage are generated globally and about half may be burned, making this a commonly overlooked major global source of emissions. We estimate a fine particle emission factor (EFPM2.5 for garbage burning of ~10.5±8.8 g/kg, which is in reasonable agreement with very limited previous work. We observe large HCl emission factors in the range 2–10 g/kg. Consideration of the Cl content of the global waste stream suggests that garbage burning may generate as much as 6–9 Tg/yr of HCl, which would make it a major source of this compound. HCl generated by garbage burning in dry environments may have a relatively greater atmospheric impact than HCl generated in humid areas. Garbage burning PM2.5 was found to contain levoglucosan and K in concentrations similar to those for

  13. Lacustrine sedimentation and facies model for the last 45,000 yr in Chalco basin. Central Mexico

    Science.gov (United States)

    Ortega, B.; Lozano, S.; Caballero, M.; Herrera, D.

    2013-05-01

    Chalco basin in central Mexico (19° 15' N, 98° 58' W, 2200 m asl) is one of the most detailed lake sediment sequence analyzed in Mexico for paleoclimatic and paleoenvironmental studies. In this former lake, five drill cores up to 27 m depth were recovered in 1987-1989 by the UNAM team, and three cores covering most of the former sequence were obtained in 2008 and 2011. The upper 27 m of the Chalco lacustrine sequence contains the record of the last 45 kyr climate history in the northern American tropics. The active tectonic and volcanic setting of Chalco Lake in the Trans-Mexican Volcanic Belt, provides an opportunity to evaluate environmental (volcanic + tectonic vs. climatic) controls on lacustrine sedimentation. The establishment of a detailed time scale by 14C in pollen extracts provides an accurate chronological control. The stratigraphical and sedimentological analyses presented here provided the recognition of depositional environments and the architecture of the upper lacustrine succession. Sedimentary facies were defined on the basis of sedimentological descriptions, microscopic observation and compositional analyses. According to compositional criteria, facies were identified and groped into two main categories according to compositional criteria: 1) detrital and volcaniclastic, and 2) biogenic facies. The clastic facies includes massive to laminated, silty and clayey sediments composed of clay minerals, feldspars, amphiboles with minor amounts of quartz, opaque minerals and calcite. Diatoms are the most common biological remains in all the clastic facies. Most of the volcaniclastic deposits correspond to fall-out deposits, some of them of well documented eruptions of the nearby large stratovolcanoes Popocatepetl and Nevado de Toluca, which in turn serve as stratigraphical markers. The biogenic facies are massive to finely laminated diatom ooze and ostracod ooze layers. The sedimentary architecture of the lacustrine succession has been controlled by

  14. Groundwater depletion in Central Mexico: Use of GRACE and InSAR to support water resources management

    Science.gov (United States)

    Castellazzi, Pascal; Martel, Richard; Rivera, Alfonso; Huang, Jianliang; Pavlic, Goran; Calderhead, Angus I.; Chaussard, Estelle; Garfias, Jaime; Salas, Javier

    2016-08-01

    Groundwater deficits occur in several areas of Central Mexico, where water resource assessment is limited by the availability and reliability of field data. In this context, GRACE and InSAR are used to remotely assess groundwater storage loss in one of Mexico's most important watersheds in terms of size and economic activity: the Lerma-Santiago-Pacifico (LSP). In situ data and Land Surface Models are used to subtract soil moisture and surface water storage changes from the total water storage change measured by GRACE satellites. As a result, groundwater mass change time-series are obtained for a 12 years period. ALOS-PALSAR images acquired from 2007 to 2011 were processed using the SBAS-InSAR algorithm to reveal areas subject to ground motion related to groundwater over-exploitation. In the perspective of providing guidance for groundwater management, GRACE and InSAR observations are compared with official water budgets and field observations. InSAR-derived subsidence mapping generally agrees well with official water budgets, and shows that deficits occur mainly in cities and irrigated agricultural areas. GRACE does not entirely detect the significant groundwater losses largely reported by official water budgets, literature and InSAR observations. The difference is interpreted as returns of wastewater to the groundwater flow systems, which limits the watershed scale groundwater depletion but suggests major impacts on groundwater quality. This phenomenon is enhanced by ground fracturing as noticed in the field. Studying the fate of the extracted groundwater is essential when comparing GRACE data with higher resolution observations, and particularly in the perspective of further InSAR/GRACE combination in hydrogeology.

  15. Origin and age of the Volcanic Rocks of Tláloc Volcano, Sierra Nevada, Central Mexico

    Science.gov (United States)

    Meier, M.; Grobéty, B.; Arce, J. L.; Rueda, H.

    2007-05-01

    The Tláloc volcano (TV) is a 4125 m high stratovolcano of the Trans Mexican Volcanic Belt (TMVB) and is located in the northern end of the N-S trending Sierra Nevada, 30 km NE of Mexico City. Few data on the petrological and temporal evolution of TV have been published to date. Recently dated deposits gave ages between 32'000 and 34'500±500 years BP (Huddart and Gonzalez, 2004). Mapping and sampling of extrusive rocks in the summit region of TV revealed a dome structure with radiating lava flows consisting of dacitic rocks containing plagioclase and hornblende phenocrysts. Some flows, however, seem to be associated with a collapse structure E of the main summit. Crossing relationships indicate that this structure is older (“Paleo Tláloc”). A stratigraphy of the pyroclastic deposits was established along the northern slope of TV. From the numerous pyroclastic flows, separated by paleosoils and fluviatile deposits, only two pumice and one block and ash flow (BAF) have regional extent. Their thickness - distance relationship and their granulometry point to major explosive events. A carbonized wood sample from the BAF deposit gave ages similar to the previous ages (33'180±550 yr BP and 23'170±270 yr BP), a sample from a pyroclastic flow gave even a younger age (16'620±110 yr BP), suggesting that TV remained active also after the volcanoes Iztaccíhuatl and Popocatépetl further to the South started their activity. Based on these preliminary data it may be necessary to reconsider the accepted scenario of the temporal evolution of the central section of the TMVB, which assumes that the activity migrates from North to South with time. Huddart, D. and Gonzalez, S., 2004. Pyroclastic flows and associated sediments, Tláloc-Telapón, piedmont fringe of the eastern basin of Mexico. In: G.J. Aguirre-Diaz, Macías, J.L., and Siebe, C., (Editor), Penrose Conference. UNAM, Metepec, Puebla, Mexico, pp. 35.

  16. Lead isotope studies of the Guerrero composite terrane, west-central Mexico: implications for ore genesis

    Science.gov (United States)

    Potra, Adriana; Macfarlane, Andrew W.

    2014-01-01

    New thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry Pb isotope analyses of three Cenozoic ores from the La Verde porphyry copper deposit located in the Zihuatanejo-Huetamo subterrane of the Guerrero composite terrane are presented and the metal sources are evaluated. Lead isotope ratios of 3 Cenozoic ores from the El Malacate and La Esmeralda porphyry copper deposits located in the Zihuatanejo-Huetamo subterrane and of 14 ores from the Zimapan and La Negra skarn deposits from the adjoining Sierra Madre terrane are also presented to look for systematic differences in the lead isotope trends and ore metal sources among the proposed exotic tectonostratigraphic terranes of southern Mexico. Comparison among the isotopic signatures of ores from the Sierra Madre terrane and distinct subterranes of the Guerrero terrane supports the idea that there is no direct correlation between the distinct suspect terranes of Mexico and the isotopic signatures of the associated Cenozoic ores. Rather, these Pb isotope patterns are interpreted to reflect increasing crustal contribution to mantle-derived magmas as the arc advanced eastward onto a progressively thicker continental crust. The lead isotope trend observed in Cenozoic ores is not recognized in the ores from Mesozoic volcanogenic massive sulfide and sedimentary exhalative deposits. The Mesozoic ores formed prior to the amalgamation of the Guerrero composite terrane to the continental margin, which took place during the Late Cretaceous, in intraoceanic island arc and intracontinental marginal basin settings, while the Tertiary deposits formed after this event in a continental arc setting. Lead isotope ratios of the Mesozoic and Cenozoic ores appear to reflect these differences in tectonic setting of ore formation. Most Pb isotope values of ores from the La Verde deposit (206Pb/204Pb = 18.674-18.719) are less radiogenic than those of the host igneous rocks, but plot within the

  17. Elevation Control on Vegetation Organization in a Semiarid Ecosystem in Central New Mexico

    Science.gov (United States)

    Nudurupati, S. S.; Istanbulluoglu, E.; Adams, J. M.; Hobley, D. E. J.; Gasparini, N. M.; Tucker, G. E.; Hutton, E. W. H.

    2015-12-01

    Many semiarid and desert ecosystems are characterized by patchy and dynamic vegetation. Topography plays a commanding role on vegetation patterns. It is observed that plant biomes and biodiversity vary systematically with slope and aspect, from shrublands in low desert elevations, to mixed grass/shrublands in mid elevations, and forests at high elevations. In this study, we investigate the role of elevation dependent climatology on vegetation organization in a semiarid New Mexico catchment where elevation and hillslope aspect play a defining role on plant types. An ecohydrologic cellular automaton model developed within Landlab (component based modeling framework) is used. The model couples local vegetation dynamics (that simulate biomass production based on local soil moisture and potential evapotranspiration) and plant establishment and mortality based on competition for resources and space. This model is driven by elevation dependent rainfall pulses and solar radiation. The domain is initialized with randomly assigned plant types and the model parameters that couple plant response with soil moisture are systematically changed. Climate perturbation experiments are conducted to examine spatial vegetation organization and associated timescales. Model results reproduce elevation and aspect controls on observed vegetation patterns indicating that this model captures necessary and sufficient conditions that explain these observed ecohydrological patterns.

  18. Canopy arthropods community within and among oak species in central Mexico

    Institute of Scientific and Technical Information of China (English)

    Efraín TOVAR-SANCHEZ

    2009-01-01

    Quercus rugosa and Q.laurina are species that presents a wide geographical distribution range in temperate forests of Mexico. Oak canopies contain a considerable portion of arthropod diversity and the arthropods fauna fulfill a wide variety of ecological roles. We examined the effect of oak species and seasonal changes on some community structure parameters (diversity, composition, similarity, biomass, rare species, and density of arthropod fauna) of canopy arthropods. In total, 40 oak canopies were fogged during rainy and dry season. A total of 614 identified arthropod morphospecies were recognized belonging to 22 orders associated with tree canopies. A separation of host tree species during both seasons, suggesting a different community structure on host plants species was demonstrated by the principal component analyses (PCA), therefore, differences between oak species results in phenotypes that structure the composition of the arthropod community. Q.laurina registered the highest densities, diversity index and number of rare species in comparison with Q.rugosa. While arthropod biomass showed an inverse pattern. Trees more close to one another (spatial distance) register a more similar canopy arthropod fauna. This study suggests that the trees of Q.laurina could act as a center of biodiversity by the accumulation of arthropod fauna with a considerable number of rare species, which presents wide ecological roles or is involved in critical processes that maintain forest ecosystems[Current Zoology 55(2):132-144,2009].

  19. Air pollutant characterization in Tula industrial corridor, Central Mexico, during the MILAGRO study.

    Science.gov (United States)

    Sosa, G; Vega, E; González-Avalos, E; Mora, V; López-Veneroni, D

    2013-01-01

    Pollutant emissions and their contribution to local and regional air quality at the industrial area of Tula were studied during a four-week period as part of the MILAGRO initiative. A recurrent shallow stable layer was observed in the morning favoring air pollutants accumulation in the lower 100 m atmospheric layer. In the afternoon the mixing layer height reached 3000 m, along with a featuring low level jet which was responsible of transporting air pollutants at regional scales. Average PM10 at Jasso (JAS) and Tepeji (TEP) was 75.1 and 36.8 μ g/m(3), respectively while average PM2.5 was 31.0 and 25.7 μ g/m(3). JAS was highly impacted by local limestone dust, while TEP was a receptor of major sources of combustion emissions with 70% of the PM10 constituted by PM2.5. Average hourly aerosol light absorption was 22 Mm(-1), while aerosol scattering (76 Mm(-1)) was higher compared to a rural site but much lower than at Mexico City. δ(13)C values in the epiphyte Tillandsia recurvata show that the emission plume directly affects the SW sector of Mezquital Valley and is then constrained by a mountain range preventing its dispersion. Air pollutants may exacerbate acute and chronic adverse health effects in this region.

  20. Late Holocene Vegetation Change in the Sierra Madre Oriental of Central Mexico

    Science.gov (United States)

    Conserva, Maria Elena; Byrne, Roger

    2002-09-01

    Past vegetation and climate changes reconstructed from a sediment core from Laguna Atezca, Molango, Mexico, provide new insights into the environmental and cultural histories of the Sierra Madre Oriental during the last 1700 yr. Pollen, microscopic charcoal, sediment chemistry, loss on ignition, and magnetic susceptibility indicate that three phases of human occupation, deforestation, and erosion (ca. A.D. 280-890, ca. A.D. 1030-1420, and ca. A.D. 1680-present) alternate with two phases of abandonment (ca. A.D. 890-1030 and ca. A.D. 1420-1680). Forest composition of the two abandonment phases differed, with cloud forest taxa ( Liquidambar, Ostrya/Carpinus, Ulmus, etc.) dominating the pollen record during the first phase, and Quercus and Pinus pollen characterizing phase two. These differences may reflect a climate change in which the second phase was drier than the first; Alternatively, the increase in Pinus and Quercus may have been caused by a human-induced decline in soil fertility. The Laguna Atezca record also differs from several other Mesoamerican paleoenvironmental records in that it shows no evidence of drought at the end of the Classic Period, ca. A.D. 900.

  1. Coupling Between Periodic Fluctuations in Stream Water Temperature and Groundwater Elevation, Central New Mexico

    Science.gov (United States)

    Jakubowski, R. T.; Bowman, R. S.

    2005-12-01

    Diurnal (24-hour) fluctuations in groundwater levels are often observed in riparian areas. They are generally attributed to periodic changes in barometric pressure, evapotranspirative demand, and recharge events. For losing streams located along semi-arid riparian corridors infiltration of surface water and advection of heat can strongly influence the subsurface hydrogeology. In fact, hourly head and temperature measurements in wells adjacent to the Rio Grande, New Mexico, have revealed diurnal groundwater fluctuations that correlate with diurnal changes in river temperature. We hypothesize that a periodic change in the streambed hydraulic conductivity modulated by variations in temperature may produce a transient flux (pressure wave) into the underlying shallow aquifer. The presence of a streambed restricting layer, diurnal changes in river temperature, limited riparian vegetation, and patterns in head during no-flow conditions in the Rio Grande support a scenario in which variable groundwater recharge from the river contributes to the diurnal head change in the aquifer. We model coupled heat and mass transport to evaluate the potential significance of the hypothesized hydrodynamic interactions.

  2. Air Pollutant Characterization in Tula Industrial Corridor, Central Mexico, during the MILAGRO Study

    Directory of Open Access Journals (Sweden)

    G. Sosa

    2013-01-01

    Full Text Available Pollutant emissions and their contribution to local and regional air quality at the industrial area of Tula were studied during a four-week period as part of the MILAGRO initiative. A recurrent shallow stable layer was observed in the morning favoring air pollutants accumulation in the lower 100 m atmospheric layer. In the afternoon the mixing layer height reached 3000 m, along with a featuring low level jet which was responsible of transporting air pollutants at regional scales. Average PM10 at Jasso (JAS and Tepeji (TEP was 75.1 and 36.8 μg/m3, respectively while average PM2.5 was 31.0 and 25.7 μg/m3. JAS was highly impacted by local limestone dust, while TEP was a receptor of major sources of combustion emissions with 70% of the PM10 constituted by PM2.5. Average hourly aerosol light absorption was 22 Mm−1, while aerosol scattering (76 Mm−1 was higher compared to a rural site but much lower than at Mexico City. δ13C values in the epiphyte Tillandsia recurvata show that the emission plume directly affects the SW sector of Mezquital Valley and is then constrained by a mountain range preventing its dispersion. Air pollutants may exacerbate acute and chronic adverse health effects in this region.

  3. Water resources on the Pueblo of Laguna, west-central New Mexico

    Science.gov (United States)

    Risser, D.W.; Lyford, F.P.

    1983-01-01

    This study evaluates the quality and quantity of water available on the Pueblo of Laguna, New Mexico. Groundwater for public supply occurs in the valley fill along the Rio San Jose, in the Paguate and Encinal areas, and possibly in the northern part of the Sedillo Grant. The valley fill in the Rio San Jose will supply 50 to 450 gallons per minute of potable water to properly constructed wells. In the alluvium along Rio Paguate, additional development of as much as 250 gallons per minute is possible. Groundwater for irrigation is restricted by available yields and quality to the valley fill along the Rio San Jose and possibly the western part of the Major 's Ranch area. In the Rio San Jose valley yields of 50 to 450 gallons per minute of water containing 500 to 3,000 milligrams per liter are possible. Digital-model simulations of the valley-fill aquifer west of the Village of Laguna show a potential salvage of as much as 900 acre-feet per year of evapotranspiration losses if water levels are lowered. Model studies also indicate that the winter flow of the Rio San Jose could be used to recharge groundwater stored in the valley. (USGS)

  4. Detection of Phytoplasma on Indian Fig (Opuntia ficus-indica Mill in Mexico Central Region

    Directory of Open Access Journals (Sweden)

    Ricardo Gaspar

    2009-01-01

    Full Text Available Problem statement: The Indian fig (a species of prickly pear cactus, has been known as Nopal, comprises an approximate area of 100,000 ha, in plantations used for human consumption. “Pyramids” Indian fig area located in the northeastern State of Mexico has been an important Indian-fig area in the country, with 15810 ha, where a phytoplasma has been consistently present in symptomatic plant. Approach: An unknown symptomatology in the Indian fig (prickly pear cactus (Opuntia ficus-indica Mill was analyzed through grafting and a nested-PCR reaction and graft on healthy plants grown in a greenhouse. Results: The symptoms found, deforming, buds proliferation, thickening and heart-shaping in cladodes, with arrested plant growth and deep yellowing of cladodes, were all attributed to the presence of a phytoplasma given the amplification of a 1200 pb fragment of the 16S rRNA gene using primers R16 F2/R2 and R16F2n/R2 and 80% of phytoplasma transmission efficiency of successful grafts. Conclusion: Although the symptoms observed did not completely match those described for this organism in the region, a 1200 pb fragment was amplified and PCR products restriction analysis leading us to assume that the phytoplasma corresponds to subgroup 16Srll, previously reported for other crops in others world regions.

  5. Pedogenesis and paleoenvironmental records in the tephra-paleosol sequences of Central Mexico: micromorphometric indicators.

    Science.gov (United States)

    Diaz, Jaime; Solleiro, Elizabeth; Sedov, Sergey

    2014-05-01

    tepetates (hardened volcanic soils) in Mexico have been studied from an agronomic and mechanisms viewpoint, however due to their different origins have not been established mechanisms that link them to environmental studies. This paper uses morphometric tools to determine the origin of the Tepetates in Mexico, using them as indicators of environmental changes and periods of instability of the landscape. The Glacis de Buenavista is located mainly in the northwestern portion of the state of Morelos, between the parallels 18° 20'and 19° 08' north latitude and meridians 98° 37' and 99° 30' west, forming a piedmont relief caused by erosion-sedimentation phases of volcanic materials from the Sierra de Zempoala mainly, and that is a big fan of Pleistocene age. Covers an area of 202.7 km 2. The maximum altitude is in the north, 2600 m, and minimun in the south to the 970 m, with an average slope of 6 . The Glacis de Buenavista has soils cover which consists of Luvisols, Vertisols, and layers of Tepetates, Phaeozems and Luvisols, in particular, represent soils polycyclic polygenetic high degree of development that have been formed in the Holocene. The next question is what mechanisms control the presence of a floor or other unit that occurs in the area? Since the lateral boundaries between soil types are abrupt, which speaks of discontinuities in the processes that have given rise. The morphometric study was carried out in thins sections of the blocks of Tepetates undisturbed. The blocks were vacuum impregnated with polyester resin. The thins sections were scanned with an Epson scanner 7100 with high resolution 9600 dpi and 24 bit color depth and analyzed using Image Pro Plus 5.1 program. The stratigraphic control was performed by 14C dating of organic matter. The pedofeatures measured were roundness of soil fragments, matrix percentage, percentage of papules and porosity. Was also carried out a microscopic control using a microscope BX51 Olimpus pedofeatures observing

  6. Pleistocene cohesive debris flows at Nevado de Toluca Volcano, central Mexico

    Science.gov (United States)

    Capra, L.; Macías, J. L.

    2000-10-01

    During the Pleistocene, intense hydrothermal alteration promoted a flank failure of the southern portion of Nevado de Toluca volcano. This event produced a debris avalanche that transformed into a cohesive debris flow (Pilcaya deposit) owing to water saturation and weakness of the altered pre-avalanche rocks. The Pilcaya debris flow traveled along a narrow tectonic depression up to a distance of 40 km and then spread over a flat plain reaching up to 55 km from the volcano summit. This transition zone corresponds with a sudden break in slope from 5 to 0.5° that caused a rapid reduction in velocity and thickening of the flow that consequently reduced its competence to transport large particles. The resulting deposit thickens from 15 to 40 m, and contains boulders up to 15 m in diameter that form hummocky morphology close to the transitional zone. Sometime after the emplacement of the Pilcaya debris flow, heavy rains and superficial drainage contributed to remobilize the upper portions of the deposit causing two secondary lahars. These debris flows called El Mogote, traveled up to 75 km from the volcano. The edifice collapse generated lahars with a total volume of 2.8 km 3 that devastated an approximate area of 250 km 2. The area versus volume plot for both deposits shows that the magnitude of the event is comparable to other cohesive debris flows such as the Teteltzingo lahar (Pico de Orizaba, Mexico) and the Osceola mudflow (Mount Rainier, Wa). The Pilcaya debris flow represents additional evidence of debris flow transformed from a flank failure, a potentially devastating phenomenon that could threaten distant areas from the volcano previously considered without risk.

  7. Geology and geochemistry characteristics of the Chiapanecan Volcanic Arc (Central Area), Chiapas Mexico

    Science.gov (United States)

    Mora, J. C.; Jaimes-Viera, M. C.; Garduño-Monroy, V. H.; Layer, P. W.; Pompa-Mera, V.; Godinez, M. L.

    2007-04-01

    The Chiapanecan Volcanic Arc (CVA), located in the central portion of the State of Chiapas, is a 150 km stretch of volcanoes irregularly aligned in the northwest direction between two great volcanic features: the Trans-Mexican Volcanic Belt to the northwest and the Central American Volcanic Arc to the southeast. The CVA is located in a complex zone marking the interaction of the North American, Caribbean and Cocos plates, near the Motagua-Polochic fault system, the boundary between North American and Caribbean plates. The central part of the CVA is composed of an irregular northwest alignment of at least 10 volcanic structures generally lying along NNW-SSE-trending faults splayed from the Motagua-Polochic system. Among the structures there are seven volcanic domes (Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza and Santotón), one explosion crater (Navenchauc), one collapse structure (Apas), and one dome complex (Tzontehuitz). In the majority of the structures there is a clear resurgence with the formation of several domes in the same structure, with the destruction of previous domes (Navenchauc) or with the formation of new explosion craters or collapse structures (Apas). The volcanic activity in the CVA was mainly effusive accompanied by explosive and phreatomagmatic events and is characterized by volcanic domes accompanied by block-and-ash-flows, ash flows with accretionary lapilli, falls, and pumice flows. The volcanic structures and deposits are calcalkaline in composition with a medium to high content of potassium. CVA volcanic rocks vary from andesite to dacite with SiO 2 between 57 and 66 wt.%, show low concentrations of Ti, P, Nb and Ta, are enriched in Light Rare Earths, depleted in Heavy Rare Earths, and show a small Eu anomaly; all indicative of arc-related volcanism associated with subduction of the Cocos plate under the North American plate, but complicated by the geometry of the plate boundary fault system.

  8. Metallogenic evolution of uranium deposits in the Middle East and North Africa deposits

    Science.gov (United States)

    Howari, Fares; Goodell, Philip; Salman, Abdulaty

    2016-02-01

    This paper is briefly involved in classification and distributions of the Middle East and North Africa (MENA) uranium deposits. The study of these mineral systems can significantly contribute to our further understanding of the metallogeny of known and poorly explored deposits. This provides contribution to, and further enhancement of, current classifications and metallogenic models of uranium systems, allowing researchers to emphasize on unknown or poorly studied mineral systems found in MENA. The present study identified eight metallogenic types of uranium associated with: 1) the Archean rocks and intra-cratonic basins, 2) the Pan-African granites and rhyolites which are characterized by igneous activity, 3) Phanerozoic (Paleozoic) clastics, these deposits are the sedimentological response to Pan African magmatism, 4) Mesozoic (basal) clastics type e.g. Nubia sandstones which are characterized by uranium minerals, 5) regional sedimentary phosphate deposits which are categorized as geosynclinal, or continental margin deposits, on the shelf of the Tethys Ocean, 6) Cenozoic Intracratonic Felsic Magmatism of the Tibesti and Hoggar, and the sandstone U deposits of adjoining Niger. These are similar to the Pan-African magmatism metallogenic, 7) Calcretes, and 8) Resistate minerals which are often enriched in rare earth elements, sometimes including uranium. They are thus sometimes considered as U resources but poorly explored in the MENA region. These metallogenic types are described and discussed in the current paper.

  9. Metallogenic Features and Metalogenic Model of Laterite Gold Deposits in Southern China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The modern laterite gold deposits in southern China, which belong to reworked laterite deposits, can be further divided into three subclasses and seven types. Their geological features, ore-forming conditions and regularities are discussed. A geologic-geochemical metallogenic model for laterite gold deposits has been established.

  10. Fault reactivation: The Picuris-Pecos fault system of north-central New Mexico

    Science.gov (United States)

    McDonald, David Wilson

    The PPFS is a N-trending fault system extending over 80 km in the Sangre de Cristo Mountains of northern New Mexico. Precambrian basement rocks are offset 37 km in a right-lateral sense; however, this offset includes dextral strike-slip (Precambrian), mostly normal dip-slip (Pennsylvanian), mostly reverse dip-slip (Early Laramide), limited strike-slip (Late Laramide) and mostly normal dip-slip (Cenozoic). The PPFS is broken into at least 3 segments by the NE-trending Embudo fault and by several Laramide age NW-trending tear faults. These segments are (from N to S): the Taos, the Picuris, and the Pecos segments. On the east side of the Picuris segment in the Picuris Mountains, the Oligocene-Miocene age Miranda graben developed and represents a complex extension zone south of the Embudo fault. Regional analysis of remotely sensed data and geologic maps indicate that lineaments subparallel to the trace of the PPFS are longer and less frequent than lineaments that trend orthogonal to the PPFS. Significant cross cutting faults and subtle changes in fault trends in each segment are clear in the lineament data. Detailed mapping in the eastern Picuris Mountains showed that the favorably oriented Picuris segment was not reactivated in the Tertiary development of the Rio Grande rift. Segmentation of the PPFS and post-Laramide annealing of the Picuris segment are interpreted to have resulted in the development of the subparallel La Serna fault. The Picuris segment of the PPFS is offset by several E-ESE trending faults. These faults are Late Cenozoic in age and interpreted to be related to the uplift of the Picuris Mountains and the continuing sinistral motion on the Embudo fault. Differential subsidence within the Miranda graben caused the development of several synthetic and orthogonal faults between the bounding La Serna and Miranda faults. Analysis of over 10,000 outcrop scale brittle structures reveals a strong correlation between faults and fracture systems. The dominant

  11. Herbivory of sympatric elk and cattle on Lincoln National Forest, south-central New Mexico

    Directory of Open Access Journals (Sweden)

    Heather H. Halbritter

    2015-09-01

    Full Text Available Background Wildlife and livestock grazing are important products of forest ecosystems, but can be controversial. Herbivory by North American elk and domestic cattle is a contentious management issue throughout western North America, often driving management proposals to decrease cattle and elk numbers based on perceived overutilization of forages. Such observations are often site level rather than landscape, and may confuse ecological sustainability with desired conditions. Methods We used line transects to document vegetation composition, structure, and grazing and browsing utilization for 4 key habitat types: mountain meadows, aspen, thinned conifer, and burned conifer on Lincoln National Forest, New Mexico, USA. We documented relative habitat use of these types by elk, mule deer, and cattle and modeled relative use on residual grass biomass of mountain meadows and browse utilization of forested types. We determined diets and diet quality of elk and cattle to assess degree of competition. Results Use of grasses in meadows was below management thresholds, and combined elk, cattle, and deer relative habitat use accounted for < 14 % of the variance in residual stubble height of Poa pratensis, the most abundant grass. Palatable browse was limited in habitat types (< 107 stems·ha -1 , use was generally high, and elk presence was correlated with the majority of browsing. Elk and cattle diets did not significantly overlap (Schoener’s index 0.54–0.57; elk fed primarily on deciduous shrubs (34 %–55 % of annual diets and cattle on grass (72 %–77 %. Digestibility and crude protein levels of cattle diets and body condition of elk indicated high quality diets for cattle and marginal–good quality diets for elk. Conclusions At observed stocking levels and densities, cattle and elk were not competing for forage based on diet similarity, nor were key habitat types being used beyond sustainable levels. Low browse availability indicates that

  12. Phenology of Bombus pennsylvanicus sonorus say (Hymenoptera: Apidae) in Central Mexico.

    Science.gov (United States)

    de la Hoz, Juan Di Trani

    2006-01-01

    We studied the seasonal activity of Bombus pennsylvanicus sonorus Say in subtropical conditions of the Mexican Central Plateau. Monthly during 1998, we recorded caste of active individuals (inferred form corporal size measured as wing length), presence and activity of reproductive individuals, and mating activity. Also, we recorded the flower plants used as resources. Subtropical conditions of the Mexican Central Plateau do not seem to modify phenological features of B. pennsylvanicus sonorus since the species presents annual colonies and a clearly defined period of inactivity. The size of individuals progressively increased between the first recorded activity period in middle April and the end of the colonies in November. Reproductive bees were observed since the second half of the year. The presence of males was recorded between July and November and queens and mating pairs were observed during November and December. Then mating queens were noted seeking hibernation places. Activity resumed in February of the following year. Seasonal activity seems to be more related to availability of floral resources (which, in turn, is related to rain regime), than to changes in temperature and day length. Some of the main food resources used by B. pennsylvanicus sonorus were Tithonia tubiformis, Cosmos bipinnatus, Anoda cristata, Solanum rostratum and Jacaranda mimosaefolia.

  13. Stratigraphy, sedimentology and paleontology of lower Eocene San Jose formation, central San Juan basin, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, S.G.; Smith, L.N. (New Mexico Museum of Natural History, Albuquerque (USA))

    1989-09-01

    The lower Eocene San Jose Formation in the central portion of the San Juan basin (Gobernador-Vigas Canyon area) consists of the Cuba Mesa, Regina, Llaves, and Tapicitos Members. Well log data indicate that, from its 100-m thickness, the Cuba Mesa Member thins toward the basin center and pinches out to the northeast by lat. 36{degree}40'N, long. 107{degree}19'W. The Regina Member has the most extensive outcrops in the central basin, and it decreases in sandstone/mud rock ratio to the north. The Llaves and Tapicitos Members occur only at the highest elevations, are thin due to erosion, and are not mappable as separate units. Well log data and 1,275 m of measured stratigraphic section in the Regina, Llaves, and Tapicitos Members indicate these strata are composed of approximately 35% medium to coarse-grained sandstone and 65% fine-grained sandstone and mud rock. Sedimentology and sediment-dispersal patterns indicate deposition by generally south-flowing streams that had sources to the northwest, northeast, and east. Low-sinuosity, sand-bedded, braided( ) streams shifted laterally across about 1 km-wide channel belts to produce sheet sandstones that are prominent throughout the San Jose Formation. Subtle levees separated channel environments from floodplain and local lacustrine areas. Avulsion relocated channels periodically to areas on the floodplain, resulting in the typically disconnected sheet sandstones within muddy overbank deposits of the Regina Member.

  14. Terminal Pleistocene to early Holocene volcanic eruptions at Zuni Salt Lake, west-central New Mexico, USA

    Science.gov (United States)

    Onken, Jill; Forman, Steven

    2017-01-01

    Zuni Salt Lake (ZSL) is a large maar in the Red Hill-Quemado volcanic field located in west-central New Mexico in the southwestern USA. Stratigraphic analysis of sections in and around the maar, coupled with optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C dating, indicate that ZSL volcanic activity occurred between ˜13.4 and 9.9 ka and was most likely confined to a ≤500-year interval sometime between ˜12.3 and 11.0 ka. The basal volcanic unit consists of locally widespread basaltic ash fallout interpreted to represent a violent or wind-aided strombolian eruption tentatively attributed to Cerro Pomo, a scoria cone ˜10 km south of ZSL. Subsequent eruptions emanated from vents near or within the present-day ZSL maar crater. Strombolian eruptions of multiple spatter and scoria cones produced basaltic lava and scoria lapilli fallout. Next, a phreatomagmatic eruption created the maar crater and surrounding tephra rim and apron. ZSL eruptions ended with strombolian eruptions that formed three scoria cones on the crater floor. The revised age range of ZSL is younger and more precise than the 190-24 ka 2-sigma age range derived from previous argon dating. This implies that other morphologically youthful, argon-dated volcanoes on the southern margin of the Colorado Plateau might be substantially younger than previously reported.

  15. Pre-eruptive conditions of the ~31 ka rhyolitic magma of Tlaloc volcano, Sierra Nevada Volcanic Range, Central Mexico

    Science.gov (United States)

    Macias, J.; Arce, J.; Rueda, H.; Gardner, J.

    2008-12-01

    Tlaloc volcano is located at the northern tip of the Sierra Nevada Volcanic Range in Central Mexico. This Pleistocene to Recent volcanic range consists from north to south of Tlaloc-Telapón-Teyotl-Iztaccíhuatl-and- Popocatépetl volcanoes. While andesitic to barely dacitic volcanism dominates the southern part of the range (i.e. Popocatépetl and Iztaccíhuatl); dacitic and rare rhyolithic volcanism (i.e. Telapón, Tlaloc) dominates the northern end. The known locus of rhyolitic magmatism took place at Tlaloc volcano with a Plinian-Subplinian eruption that occurred 31 ka ago. The eruption emplaced the so-called multilayered fallout and pumiceous pyroclastic flows (~2 km3 DRE). The deposit consists of 95% vol. of juvenile particles (pumice + crystals) and minor altered lithics 5% vol. The mineral association of the pumice fragments (74-76 % wt. SiO2) consists of quartz + plagioclase + sanidine + biotite and rare oxides set in a glassy groundmass with voids. Melt inclusions in quartz phenocrysts suggest that prior to the eruption the rhyolitic contain ~7% of H2O and Toluca volcano (~6 km) some 50 km to the southwest.

  16. Economic analysis of alternative nutritional management of dual-purpose cow herds in central coastal Veracruz, Mexico.

    Science.gov (United States)

    Absalón-Medina, Victor Antonio; Nicholson, Charles F; Blake, Robert W; Fox, Danny Gene; Juárez-Lagunes, Francisco I; Canudas-Lara, Eduardo G; Rueda-Maldonado, Bertha L

    2012-08-01

    Market information was combined with predicted input-output relationships in an economic analysis of alternative nutritional management for dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. Cow productivity outcomes for typical management and alternative feeding scenarios were obtained from structured sets of simulations in a companion study of productivity limitations and potentials using the Cornell Net Carbohydrate and Protein System model (Version 6.0). Partial budgeting methods and sensitivity analysis were used to identify economically viable alternatives based on expected change in milk income over feed cost (change in revenues from milk sales less change in feed costs). Herd owners in coastal Veracruz have large economic incentives, from $584 to $1,131 in predicted net margin, to increase milk sales by up to 74% across a three-lactation cow lifetime by improving diets based on good quality grass and legume forages. This increment is equal to, or exceeds, in value the total yield from at least one additional lactation per cow lifetime. Furthermore, marginal rates of return (change in milk income over feed costs divided by change in variable costs when alternative practices are used) of 3.3 ± 0.8 indicate clear economic incentives to remove fundamental productivity vulnerabilities due to chronic energy deficits and impeded growth of immature cows under typical management. Sensitivity analyses indicate that the economic outcomes are robust for a variety of market conditions.

  17. Farm and socio-economic characteristics of smallholder milk producers and their influence on technology adoption in Central Mexico.

    Science.gov (United States)

    García, Carlos Galdino Martínez; Dorward, Peter; Rehman, Tahir

    2012-08-01

    In order to identify the factors influencing adoption of technologies promoted by government to small-scale dairy farmers in the highlands of central Mexico, a field survey was conducted. A total of 115 farmers were grouped through cluster analysis (CA) and divided into three wealth status categories (high, medium and low) using wealth ranking. Chi-square analysis was used to examine the association of wealth status with technology adoption. Four groups of farms were differentiated in terms of farms' dimensions, farmers' education, sources of incomes, wealth status, management of herd, monetary support by government and technological availability. Statistical differences (p technologies identified, six of which focused on crop or forage production and 11 of which were related to animal husbandry. Relatives and other farmers played an important role in knowledge diffusion and technology adoption. Although wealth status had a significant association (p technology to farmers, usefulness and productive benefits of innovations together with farmers' knowledge of them, were important. It is concluded that the analysis of the information per group and wealth status was useful to identify suitable crop or forage related and animal husbandry technologies per group and wealth status of farmers. Therefore the characterizations of farmers could provide a useful starting point for the design and delivery of more appropriate and effective extension.

  18. Decadal to millennial-scale solar forcing of Last Glacial Maximum climate in the Estancia Basin of central New Mexico

    Science.gov (United States)

    Menking, Kirsten M.

    2015-05-01

    Lacustrine sediments from the Estancia Basin of central New Mexico reveal decadal to millennial oscillations in the volume of Lake Estancia during Last Glacial Maximum (LGM) time. LGM sediments consist of authigenic carbonates, detrital clastics delivered to the lake in stream flow pulses, and evaporites that precipitated in mudflats exposed during lake lowstands and were subsequently blown into the lake. Variations in sediment mineralogy thus reflect changes in hydrologic balance and were quantified using Rietveld analysis of X-ray diffraction traces. Radiocarbon dates on ostracode valve calcite allowed the construction of mineralogical time series for the interval ~ 23,600 to ~ 18,300 ka, which were subjected to spectral analysis using REDFIT (Schulz and Mudelsee, 2002). Dominant periods of ~ 900, ~ 375, and ~ 265 yr are similar to cycles in Holocene 14C production reported for a variety of tree ring records, suggesting that the Lake Estancia sediments record variations in solar activity during LGM time. A prominent spectral peak with a period of ~ 88 yr appears to reflect the solar Gleissberg cycle and may help, along with the ~ 265 yr cycle, to explain an ongoing mystery about how Lake Estancia was able to undergo abrupt expansions without overflowing its drainage basin.

  19. Economic contribution of draught animals to Mazahua smallholder Campesino farming systems in the highlands of Central Mexico.

    Science.gov (United States)

    Arriaga-Jordán, C M; Pedraza-Fuentes, A M; Velázquez-Beltrán, L G; Nava-Bernal, E G; Chávez-Mejía, M C

    2005-10-01

    The economic contribution of draught animals to smallholder Mazahua campesino systems in two mountain villages of San Felipe del Progreso, in the central highlands of Mexico, was assessed. Campesinos rely on draught animals for cultivation tasks, as pack animals, and as transport for agricultural and domestic activities. The villages were San Pablo Tlalchichilpa (SPT) and La Concepción Mayorazgo (LCM). Twelve households that possessed draught animals were monitored from July 1999 to June 2000, nine in SPT and three in LCM, in terms of animal inventories and income from their draught animals, in cash and opportunity values. Equines in SPT have substituted bulls, and are recognized for their multipurpose contribution, while in LCM bulls are still used for ploughing the land. Overall total mean gross income was US dollar 490.78 per farm per year, plus US dollar 56 as opportunity value of the fertilizer value of manure for both villages. Deducting estimated costs, owning draught animals leaves a mean net margin of US dollar 412.50/year in SPT and of US dollar 285.64/year in LCM. There is a significant correlation (p < 0.05) between ownership of draught animals and incomes, with a regression coefficient of US dollar 279.16 per year per draught animal. Besides positive economic returns, having work animals alleviates drudgery for the campesino families.

  20. Evaluation of NEXRDA Stage III precipitation data over Sevilleta National Wildlife Refuge: a semiarid region in Central New Mexico

    Science.gov (United States)

    Xie, H.; Zhou, X.; Hendrickx, J.; Guan, H.

    2006-05-01

    This study examines NEXRAD Stage III product (hourly, cell size 4 km by 4 km) for its ability in estimating precipitation over Sevilleta National Wildlife Refuge: a semiarid region in Central New Mexico. A GIS-based NEXRAD data processing and visualization method is also presented. A comparison between Stage III and a network of gauge precipitation estimates during 1995 to 2001 indicates that Stage III (1) overestimates the hourly conditional mean precipitation (CM) by 33 percent in monsoon season and 55 percent in non-monsoon season; (2) overestimates the hourly CM for concurrent radar-gauge pairs (non-zero value) by 13 percent in monsoon season and 6 percent in non-monsoon season; (3) overestimates the seasonal precipitation accumulation by 11 to 88 percent in monsoon season and underestimates by 18 to 89 percent in non- monsoon season; and (4) either overestimates annual precipitation accumulation up to 28.2 percent or underestimates it up to 11.9 percent. More caution is suggested in using Stage III data for nonmonsoonal (stratiform) rainfall events (prior to the truncation fixed algorithm deployed in 2002), as the truncation error can be a significant drawback. While overestimates may suppress the truncation caused underestimates in the monsoon seasons.

  1. Aquifer tests at the Jackpile-Paguate uranium mine, Pueblo of Laguna, west-central New Mexico

    Science.gov (United States)

    Risser, D.W.; Davis, P.A.; Baldwin, J.A.; McaAda, D.P.

    1984-01-01

    The transmissivity of the Jackpile sandstone bed in the Brushy Basin Shale Member of the Morrison Formation, west-central New Mexico, was determined to be 24 sq ft/day at well M2 and 47 sq ft/day at well M3 from constant-discharge aquifer tests conducted at the Jackpile-Paguate Uranium Mine. The storage coefficient of the Jackpile sandstone bed was estimated to be 0.00018 at well M2 and 0.00029 at well M3 from the same tests. An aquifer test conducted at well M21 indicated the transmissivity of the Jackpile sandstone bed was 2.0 sq ft/day and the storage coefficient was 0.00002. The transmissivity of an unnamed sandstone bed in the Brushy Basin Shale Member of the Morrison Formation was estimated from ' slug-test ' results to be about 20 sq ft/day. Water levels in this sandstone probably did not change due to pumping from the overlying Jackpile sandstone bed for 88 hours at an average discharge of 15.3 gallons/min. A constant discharge aquifer test at well M4C indicated that the transmissivity of the alluvium at this location was about 430 sq ft/day. Water levels in the underlying Jackpile sandstone bed began declining within 15 minutes after withdrawals of groundwater from the alluvial aquifer began. (USGS)

  2. Bacterial community structure in the rhizosphere of three cactus species from semi-arid highlands in central Mexico.

    Science.gov (United States)

    Aguirre-Garrido, J Félix; Montiel-Lugo, Daniel; Hernández-Rodríguez, César; Torres-Cortes, Gloria; Millán, Vicenta; Toro, Nicolás; Martínez-Abarca, Francisco; Ramírez-Saad, Hugo C

    2012-05-01

    The nature reserve of Tehuacan-Cuicatlan in central Mexico is known for its diversity and endemism mainly in cactus plants. Although the xerophytic flora is reasonably documented, the bacterial communities associated with these species have been largely neglected. We assessed the diversity and composition of bacterial communities in bulk (non-rhizospheric) soil and the rhizosphere of three cactus plant species: Mammillaria carnea, Opuntia pilifera and Stenocereus stellatus, approached using cultivation and molecular techniques, considering the possible effect of dry and rainy seasons. Cultivation-dependent methods were focused on putative N(2)-fixers and heterotrophic aerobic bacteria, in the two media tested the values obtained for dry season samples grouped together regardless of the sample type (rhizospheric or non-rhizospheric), these groups also included the non-rhizospheric sample for rainy season, on each medium. These CFU values were smaller and significantly different from those obtained on rhizospheric samples from rainy season. Genera composition among isolates of the rhizospheric samples was very similar for each season, the most abundant taxa being α-Proteobacteria, Actinobacteria and Firmicutes. Interestingly, the genus Ochrobactrum was highly represented among rhizospheric samples, when cultured in N-free medium. The structure of the bacterial communities was approached with molecular techniques targeting partial 16S rRNA sequences such as denaturing gradient gel electrophoresis and serial analysis of ribosomal sequence tags. Under these approaches, the most represented bacterial phyla were Actinobacteria, Proteobacteria and Acidobacteria. The first two were also highly represented when using isolation techniques.

  3. Tillandsia usneoides L, a biomonitor in the determination of Ce, La and Sm by neutron activation analysis in an industrial corridor in Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Isaac-Olive, K. [Facultad de Medicina. Universidad Autonoma del Estado de Mexico, Paseo Tollocan s/n, esq. Jesus Carranza, Toluca, 50120 Estado de Mexico (Mexico); Solis, C., E-mail: corina@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF (Mexico); Martinez-Carrillo, M.A; Andrade, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF (Mexico); Lopez, C.; Longoria, L.C. [Instituto Nacional de Investigaciones Nucleares (ININ), Salazar, 50045 Estado de Mexico (Mexico); Lucho-Constantino, C.A. [Universidad Politecnica de Pachuca, Carretera Pachuca-Cd. Sahagun, Km. 20., Hidalgo, Mexico (Mexico); Beltran-Hernandez, R.I. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo. Carretera Pachuca-Tulancingo km. 4.5, 42184, Pachuca, Hidalgo (Mexico)

    2012-04-15

    The atmosphere of the Tula Industrial Corridor in Central Mexico is contaminated due to several industries including oil refining while station monitoring in this area are limited. Lanthanides are considered fingerprint of oil refinery activities, and La, Ce and Sm have been previously detected in this area using filters. The suitability of T. usneoides as a biomonitor assessing the La, Ce and Sm concentrations in Particulate Matter is evaluated by NAA. Results of both biomonitor and filters are highly correlated.

  4. Evaluation of habitat use by Rocky Mountain elk (Cervus elaphus nelsoni) in north-central New Mexico using global positioning system radio collars

    Energy Technology Data Exchange (ETDEWEB)

    Biggs, J.; Bennett, K.; Fresquez, P.R.

    1997-04-01

    In 1996 the authors initiated a study to identify habitat use in north-central New Mexico by Rocky Mountain elk (Cervus elaphus nelsoni) using global positioning system (GPS) radio collars. They collared six elk in the spring of 1996 with GPS radio collars programmed to obtain locational fixes every 23 h. Between April 1, 1996 and January 7, 1997, they collected >1,200 fixes with an approximately 70% observation rate. They have interfaced GPS locational fixes of elk and detailed vegetation maps using the geographical information system to provide seasonal habitat use within mountainous regions of north-central New Mexico. Based on habitat use and availability analysis, use of grass/shrub and pinon/juniper habitats was generally higher than expected during most seasons and use of forested habitats was lower than expected. Most of the collared elk remained on LANL property year-round. The authors believe the application of GPS collars to elk studies in north-central New Mexico to be a more efficient and effective method than the use of VHF (very-high frequency) radio collars.

  5. Evolution of the central Rio Grande rift, New Mexico: New potassium-argon ages

    Science.gov (United States)

    Baldridge, W. S.; Damon, P. E.; Shafiqullah, M.; Bridwell, R. J.

    1980-12-01

    New K sbnd Ar age determinations on mid-Oligocene to Pleistocene volcanic and shallow intrusive rocks from the central Rio Grande rift permit a more detailed understanding of the tectonic and magmatic history of the rift. Initial extension in the region of the central rift may have begun prior to 27 m.y. ago. By 25 m.y. ago broad basins existed and were filling with volcaniclastic sediments derived mainly from volcanic centers in the San Juan and Questa areas. Continued tectonic activity narrowed these basins by 21-19 m.y. ago, indicated in the Santa Fe area by tilting and faulting that immediately postdate 20-m.y.-old latite. Uplift of the Sangre de Cristo, Sandia, and Nacimiento Mountains shed clastic debris of the Santa Fe Group into these basins. Early rift magmatism is characterized by an overlap of mid-Tertiary intermediate intrusive and extrusive activity, extending to 20 m.y. ago, with mafic and ultramafic volcanism, ranging from 25 to 19 m.y. Both volcanism and tectonic activity were minimal during the middle Miocene. About 13 m.y. ago renewed volcanic activity began. Tectonism commenced in the late Miocene, resulting in the present, narrow grabens. The term "Rio Grande rift" should be restricted to these grabens formed during post-mid-Miocene deformation. Widespread eruption of tholeiitic and alkali olivine basalts occurred 3-2 m.y. ago. The Rio Grande drainage system was integrated 4.5-3 m.y. ago, leading to the present erosional regime. These intervals of deformation and magmatism correspond generally with a similar sequence of events in the Basin and Range province south of the Colorado Plateau. This similarity indicates that the Rio Grande rift is not a unique structure in the southwestern U.S., and must be related to the larger context of the entire Basin and Range province.

  6. Is the extension of the Mexican Mesa Central (southern Basin & Range province) related to a gravitational collapse toward the Gulf of Mexico?

    Science.gov (United States)

    Andreani, L.; Rangin, C.; Le Pichon, X.; Martínez-Reyes, J.; Le Roy, C.

    2009-04-01

    The middle to late Cenozoic extension that generated the Basin and Range province (western North America) is one of the most important tectonic events to affect the North American plate. The characteristics of this extension have been extensively studied, but its origin is equally extensively debated. Proposed origins can be broadly categorized into interplate mechanisms that focus on various interactions between the Pacific or Farallon and North American plates and intraplate mechanisms that interpret extension to result from the gravitational collapse of a previously overthickened crust. It is commonly admitted that the Basin and Range extension in western Mexico migrated from East to West toward the Gulf of California. Middle to late Miocene extension around the Gulf of California (Gulf Extensional Province) is commonly interpreted as resulting from partitioning of oblique Pacific-North American plate motion into strike-slip displacement along the margin and ENE extension perpendicular to the margin within the North American plate. It is generally assumed that this mechanism also applies to the kinematically similar, predominantly ENE extension that occurred at the same time throughout the southern Basin and Range province. However structural data we collected in the Mesa Central area, along the eastern part of the Mexican Basin and Range province, argue for a post-27My N130° extension toward the Gulf of Mexico that produced highly asymmetrical grabens, with a major motion along their western flanks. Our recent works, based on the interpretation of seismic profiles, also show that the late Oligocene to present deformation along the western margin of the Gulf of Mexico was generated by a crustal shortening. In spite of a low crustal thickness the Mesa Central is an uplifted plateau with a mean altitude of 1800m. This elevation of the Mesa Central is mainly due to the high thermal gradients that characterize the back arc domain. By contrast the crust of the Gulf

  7. Microanalysis of the aerosol collected over south-central New Mexico during the alive field experiment, May-December 1989

    Science.gov (United States)

    Sheridan, Patrick J.; Schnell, Russel C.; Kahl, Jonathan D.; Boatman, Joe F.; Garvey, Dennis M.

    Thirty-eight size-segregated aerosol samples were collected in the lower troposphere over the high desert of south-central New Mexico, using cascade impactors mounted onboard two research aircraft. Four of these samples were collected in early May, sixteen in mid-July, and the remaining ones in December 1989, during three segments of the ALIVE field initiative. Analytical electron microscope analyses of aerosol deposits and individual particles from these samples were performed to physically and chemically characterize the major particulate species present in the aerosol. Air-mass trajectories arriving at the sampling area in the May program were quite different from those calculated for the July period. In general, the May trajectories showed strong westerly winds, while the July winds were weaker and southerly, consistently passing over or very near the border cities of El Paso, Texas, and Ciudad Juarez, Mexico. Aerosol samples collected during the May period were predominantly fine (0.1-0.5 μm dia.), liquid H 2SO 4 droplets. Samples from the July experiment were comprised mostly of fine, solid (NH 4) 2SO 4 or mostly neutralized sulfate particles. In both sampling periods, numerous other particle classes were observed, including many types with probable terrestrial or anthropogenic sources. The numbers of these particles, however, were small when compared with the sulfates. Composite particle types, including sulfate/crustal and sulfate/carbonaceous, were also found to be present. The major differences in aerosol composition between the May and July samples (i.e. the extensive neutralization of sulfates in the July samples) can be explained by considering the different aerosol transport pathways and the proximity of the July aerosol to the El Paso/Juarez urban plume. Winds during the December experiment were quite variable, and may have contributed to the widely varying aerosol compositions observed in these samples. When the aircraft sampled the El Paso

  8. Eruptive History of the Rhyolitic Guangoche Volcano, Los Azufres Volcanic Field, Central Mexico

    Science.gov (United States)

    Rangel Granados, E.; Arce, J. L.; Macias, J. L.; Layer, P. W.

    2014-12-01

    Guangoche is a rhyolitic and polygenetic volcano with a maximum elevation of 2,760 meters above sea level. It is situated to the southwest of the Los Azufres Volcanic Field (LAVF), in the central sector of the Trans-Mexican Volcanic Belt. Guangoche volcano is the youngest volcano described within the LAVF. It shows a horseshoe shaped crater open to the south, with a central lava dome. Its eruptive history during late Pleistocene has been intense with six explosive eruptions that consists of: 1) A southwards sector collapse of the volcano that generated a debris avalanche deposit with megablocks of heterogenous composition; 2) A plinian-type eruption that generated a pumice fall deposit and pyroclastic density currents by column collapse at 30.6 ka; 3) A plinian-type eruption "White Pumice Sequence" (29 ka) that developed a 22-km-high eruptive column, with a MDR of 7.0 x 107 kg/s (vol. = 0.53 km3); 4) A dome-destruction event, "Agua Blanca Pyroclastic Sequence" at 26.7 ka, that deposited a block-and-ash flow deposit; 5) A subplinian-plinian type eruption "Ochre Pyroclastic Sequence" (<26 ka) with an important initial phreatomagmatic phase, that generated pyroclastic density currents and pumice fallouts. The subplinian-plinian event generated a 16-km-high eruptive column, with a MDR of 1.9 x 107 kg/s, and magma volume of 0.38 km3; 6) The eruptive history ended with a subplinian eruption (<<26 ka), that generated a multilayered fall deposit, that developed a 11-km-high eruptive column, with a MDR of 2.9 x 106 kg/s and a magma volume of 0.26 km3. Volcanic activity at Guangoche volcano has been intense and future activity should not be discarded. Unfortunately, the last two events have not been dated yet. Guangoche rhyolitic magma is characterized by low-Ba contents suggesting crystal mush extraction for their genesis.

  9. A taxonomic study of Albizia (Leguminosae: Mimosoideae: Ingeae in Mexico and Central America

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    Rico Arce, María de Lourdes

    2008-12-01

    Full Text Available The genus Albizia is economically and environmentally important because many elements are multipurpose trees. A taxonomic study of 12 Central American and Mexican Albizia species is presented. Identification keys, illustrations and ecological information are provided together with some taxonomic comments. Distribution maps and conservation status are given for each native species in the area. Three epithets are lectotypyfied and three new name combinations are made. An interactive identification electronic key is available from the authors if requested. Full specimen records are available at www.kew.org/herbcat .El género Albizia tiene importancia económica y ecológica porque en su mayoría está integrado por árboles con usos múltiples. Se presenta un estudio taxonómico para 12 especies con distribución en México y Centro América, se incluyen claves para la identificación de las especies, ilustraciones, mapas de distribución, estados de conservación de las especies nativas del área y comentarios ecológicos y taxonómicos. Se formaliza la lectipificacion de tres epítetos y se proponen tres nuevas combinaciones. Una clave electrónica interactiva para la identificación de las especies se puede solicitar a los autores. Finalmente el conjunto completo de los ejemplares de herbario puede ser consultado en el sitio Web de los Jardines Reales de Kew: www.kew.org/herbcat.

  10. A Geodynamical Perspective on the Subduction of Cocos and Rivera plates beneath Mexico and Central America

    Science.gov (United States)

    Constantin Manea, Vlad; Manea, Marina; Ferrari, Luca

    2013-04-01

    The Middle America subduction zone (MASZ) is one of the world most complex convergent margins as it involves the subduction of the Rivera and Cocos young oceanic plates beneath the North American and Caribbean plates and is bounded by the Gulf of California rift and the Panama slab window. Characterized by contorted and unusual slab geometry, irregularly distributed seismicity and volcanism, exceptionally large slow slip events (SSE) and non-volcanic tremors (NVT), this subduction system represents a great natural laboratory for better understanding geodynamic processes at a fundamental level. Based on a solid observational foundation, and incorporating the latest experimental results into a coherent geodynamical framework, we shed light on the main processes controlling the subduction system evolution in this region. The tectonics, volcanism, slab geometry and segmentation along the margin are reviewed from a geodynamical perspective. We proposed and discussed a series of evolutionary scenarios for the Mexican and Central American subduction zones, providing a coherent starting base for future geodynamical modeling studies tailored to this active margin. We discuss comparatively the recently discovered SSEs and NVTs along the MASZ, and try to differentiate among the proposed mechanisms responsible for these observations. Finally we discuss the recent seismic anisotropy observations in a geodynamic context, offering an integrated view of mantle flow pattern along the entire active margin. Although the MASZ as a whole may be considered a fairly complicated region with many unusual features and sometimes controversial interpretations, its complexity and unusual characteristics can improve our knowledge about the linkage between deep and surface processes associated with subduction zone dynamics.

  11. GPR and Magnetic Modeling on an Archaeological Site in Central Mexico

    Science.gov (United States)

    Chavez, R. E.; Argote, D. L.; Camara, M. E.; Cifuentes, G.; Lopez, P.

    2007-05-01

    A geophysical study was carried out in an archaeological site called Los Teteles de Ocotitla, which means `bunch of rocks'. The area is located within the central portion of the Sierra de Ocotitla, towards the northeast of La Malinche volcano, in the municipality of Altzayanca, State of Tlaxcala. This site is conformed of several artificial terraces with evidence of human occupation, probably from the Teotihuacan or Tenanyecac phase. At first the presence of several hills, which are the remains of small pyramids can be seen. Also, some exposed walls and floors can be appreciated. The geophysical work included magnetic (vertical field) and GPR observations in five terraces. The magnetic data depicted a series of dipolar anomalies probably related to walls, and stairways. A report from a previous archaeological excavation carried out almost 30 years ago on an upper terrace, mentioned the discovery of an ancient burial. The tomb was a room (3x2x2 m3) to a depth of 1 m, where corpse remains were found, along other archaeological artifacts. Magnetic and GPR profiles were observed in this area to define geophysical signatures of the mentioned ancient structure, to later compare with anomalies obtained in other terraces. Two interesting anomalies were observed in two lower terraces that compared well with the signatures obtained. The magnetic anomalies were modeled employing a 3D inverse approach, assuming that the Earth is conformed of a series of magnetic dipoles. The final result produced a magnetic block of 5x3x3 m3 to a depth of 1.5 m, approximately. The GPR anomalies helped to constrain the initial geometry of the archaeological structure.

  12. Nitrogen, carbon and phosphorus mineralization in soils from semi-arid highlands of central Mexico amended with tannery sludge.

    Science.gov (United States)

    Barajas-Aceves, M; Dendooven, L

    2001-04-01

    Tannery sludge contains valuable nutrients and could be used as a fertilizer to pioneering vegetation in heavily eroded soils of the semi-arid highlands of central Mexico. Soil collected under and outside the canopy of mesquite (Prosopis laeviginata), huizache (Acacia tortuoso) and catclaw (Mimosa biuncifera), and cultivated with maize (Zea mays) and beans (Phaesolus vulgaris) was amended with 1.5 g tannery sludge kg-1 soil or 210 kg dry sludge ha-1 or left unamended. Amended and unamended soils were incubated aerobically for 70 days at 22 +/- 2 degrees C and CO2 production, available P, and inorganic N concentrations were monitored. The CO2 production rate, total C and P, available P, biomass C and P were larger under the canopy of the vegetation than outside of the canopy. The soils were depleted of N as more than 50 mg N kg-1 soil could not be accounted for in the first days of the incubation. Nitrification showed a lag, which lasted 28 days, and concentration of available P remained constant or increased slightly. Application of tannery sludge to soil increased CO2 production with 6.5 mg CO2 kg-1 soil d-1 and inorganic N with 30 mg N kg-1 soil after 70 days, but available P did not increase. Application of tannery sludge increased C and N mineralization and could thus provide valuable nutrients to a pioneer vegetation. Although no inhibitory effects on the biological functioning of the soil were found, further investigation into possible long-term environmental effects are necessary.

  13. Linking hydropedology and ecosystem services: differential controls of surface field saturated hydraulic conductivity in a volcanic setting in central Mexico

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    A. Gómez-Tagle

    2009-03-01

    Full Text Available In this study the variation of field saturated soil hydraulic conductivity (Kfs as key control variable and descriptor of infiltration was examined by means of a constant head single ring infiltrometer. The study took place in five coverage types and land uses in a volcanic setting in central Mexico. The tested hypothesis was that there exist a positive relationship between plant cover and surface Kfs for the study area. The examined coverage types included; Second growth pine-oak forest, pasture land, fallow land, gully and Cupresus afforestation. Results indicate that Kfs did not depend exclusively of plant cover; it was related to surface horizontal expression of the unburied soil horizons and linked to land use history. Therefore the Kfs measured at a certain location did not depend exclusively of the actual land use, it was also influenced by soil bioturbation linked to plant succession patterns and land use management practices history. The hypothesis accounts partially the variation between sites. Kfs under dense plant cover at the Cupresus afforestation was statistically equal to that measured at the fallow land or the gully sites, while second growth pine-oak forest Kfs figures were over an order of magnitude higher than the rest of the coverage types. The results suggest the relevance of unburied soil horizons in the soil hydrologic response when present at the surface. Under these conditions loosing surface soil horizons due to erosion, not only fertility is lost, but environmental services generation potential. A conceptual model within the hydropedological approach is proposed. It explains the possible controls of Kfs, for this volcanic setting. Land use history driven erosion plays a decisive role in subsurface horizon presence at the surface and soil matrix characteristic determination, while plant succession patterns seem to be strongly linked to soil bioturbation and

  14. Students and Teachers’ Reasons for Using the First Language Within the Foreign Language Classroom (French and English in Central Mexico

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    Mora Pablo Irasema

    2011-11-01

    Full Text Available

    The present study explores the use of the first language in a context of foreign language teaching. This qualitative research presents the classroom practice and points of view of French and English teachers and students within a public educational institute in central Mexico using the techniques of questionnaires and semi-structured interviews. The results show that teachers and the majority of students perceive the use of the first language as positive and part of the teaching and learning process. A small number of students do not like the use of the first language in the classroom and prefer that their teachers use the target language only.

     

    La presente investigación explora el uso de la lengua materna en un contexto de enseñanza de lenguas extranjeras. Esta investigación cualitativa presenta la práctica docente y los puntos de vista de maestros y alumnos de francés e inglés en el contexto de una universidad pública del centro de México, mediante el uso de las técnicas del cuestionario y la entrevista semiestructurada. Los resultados muestran que tanto los maestros como la mayoría de los alumnos perciben el uso de la lengua materna como algo positivo en el proceso de enseñanza-aprendizaje. Un número reducido de estudiantes rechaza el uso de la lengua materna y prefiere que su clase de lengua extranjera sea dirigida exclusivamente en la lengua meta. Palabras clave: investigación cualitativa, puntos de vista de alumnos y maestros, uso de la lengua materna.

  15. Contribution of family labour to the profitability and competitiveness of small-scale dairy production systems in central Mexico.

    Science.gov (United States)

    Posadas-Domínguez, Rodolfo Rogelio; Arriaga-Jordán, Carlos Manuel; Martínez-Castañeda, Francisco Ernesto

    2014-01-01

    The objective of this work was to determine the effect of family labour on the profitability and competitiveness of small-scale dairy farms in the highlands of Central Mexico. Economic data from 37 farms were analysed from a stratified statistical sampling with a Neyman assignment. Three strata were defined taking herd size as criterion. Stratum 1: herds from 3 to 9 cows plus replacements, Stratum 2: herds from 10 to 19 cows and Stratum 3: herds from 20 to 30 cows. The policy analysis matrix was used as the method to determine profitability and competitiveness. The coefficient of private profitability (CPP) when the economic cost of family labour is included in the cost structure was 8.0 %, 31.0 % and 46.0 %. When the economic cost of family labour is not included, CPP increase to 47.0 %, 57.0 % and 66.0 % for each strata, respectively. The private cost ratio (PCR) when family labour is included was 0.79, 0.51 and 0.42 for strata 1, 2 and 3, respectively. When family labour is not included, the PCR was 0.07, 0.25 and 0.26. Net profit per litre of milk including family labour was US$0.03 l(-1) for Stratum 1, US$0.09 for Stratum 2 and US$0.12 l(-1) for Stratum 3; but increased to $0.12, 0.14 and 0.15, respectively, when the economic cost of family labour is not included. It is concluded that family labour is a crucial factor in the profitability and competitiveness of small-scale dairy production.

  16. Genetic variation and evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacán Valley, central Mexico.

    Science.gov (United States)

    Otero-Arnaiz, Adriana; Casas, Alejandro; Hamrick, James L; Cruse-Sanders, Jennifer

    2005-05-01

    Polaskia chichipe is a columnar cactus under artificial selection in central Mexico because of its edible fruits. Our study explored the effect of human manipulation on levels and distribution of genetic variation in wild, silviculturally managed and cultivated sympatric populations. Total genetic variation, estimated in nine populations with five microsatellite loci, was H(T) = 0.658 +/- 0.026 SE, which was mainly distributed within populations (H(S) = 0.646) with low differentiation among them (F(ST) = 0.015). Fixation index (F(IS)) in all populations was positive, indicating a deficit of heterozygous individuals with respect to Hardy-Weinberg expectations. When populations were pooled by management type, the highest expected heterozygosity (H(E) = 0.631 +/- 0.031 SE) and the lowest fixation index (F(IS) = 0.07) were observed in wild populations, followed by cultivated populations (H(E) = 0.56 +/- 0.03 SE, F(IS) = 0.14), whereas the lowest variation was found in silviculturally managed populations (H(E) = 0.51 +/- 0.05 SE, F(IS) = 0.17). Low differentiation among populations under different management types (F(ST) 0.005, P < 0.04) was observed. A pattern of migration among neighbouring populations, suggested from isolation by distance (r2 = 0.314, P < 0.01), may have contributed to homogenizing populations and counteracting the effects of artificial selection. P. chichipe, used and managed for at least 700 generations, shows morphological differentiation, changes in breeding system and seed germination patterns associated with human management, with only slight genetic differences detected by neutral markers.

  17. 23,000 yr of vegetation history of the Upper Lerma, a tropical high-altitude basin in Central Mexico

    Science.gov (United States)

    Lozano-García, Socorro; Sosa-Nájera, Susana; Sugiura, Yoko; Caballero, Margarita

    2005-07-01

    Pollen analysis on a 9.54-m sediment core from lake Chignahuapan in the upper Lerma basin, the highest intermontane basin in Central Mexico (2570 m asl), documents vegetation and limnological changes over the past ˜23,000 14C yr. The core was drilled near the archaeological site of Santa Cruz Atizapán, a site with a long history of human occupation, abandoned at the end of the Epiclassic period (ca. 900 AD). Six radiocarbon AMS dates and two well-dated volcanic events, the Upper Toluca Pumice with an age of 11,600 14C yr B.P. and the Tres Cruces Tephra of 8500 14C yr B.P., provide the chronological framework for the lacustrine sequence. From ca. 23,000 14C yr B.P. to ca. 11,600 14C yr B.P. the plant communities were woodlands and grasslands based on the pollen data. The glacial advances MII-1 and MII-2 correlate with abundant non-arboreal pollen, mainly grasses, from ca. 21,000 to 16,000 14C yr B.P., and at ca. 12,600 14C yr B.P. During the late Pleistocene, lake Chignahuapan was a shallow freshwater lake with a phase of lower level between 19,000 and 16,000 14C yr B.P. After 10,000 14C yr B.P., tree cover in the area increased, and a more variable lake level is documented. Late Holocene (ca. 3100 14C yr B.P.) deforestation was concurrent with human population expansion at the beginning of the Formative period (1500 B.C.). Agriculture and manipulation of the lacustrine environment by human lakeshore populations appear at 1200 14C yr B.P. (550 A.D.) with the appearance of Zea mays pollen and abundant charcoal particles.

  18. Distribution and health risk assessment of some organic and inorganic substances in a petroleum facility in central Mexico

    Science.gov (United States)

    Flores-Serrano, R. M.; Torres, L. G.; Flores, C.; Castro, A.; Iturbe, R.

    An oil distribution and storage station was subjected to an Environmental Auditory and results showed soil contamination in part of the surface. An assessment of the site was required in order to fulfill a complete characterization of the contaminants present in soil and groundwater, as well as to establish the probable sources of contamination. Besides, a health risk assessment was performed to set remediation goals. The aim of this work is to show how the entire characterization and risk assessment process performed in this storage station from central Mexico, regarding to subsoil and groundwater. Thirty sample points were examined. Total petroleum hydrocarbons concentrations in soil were in a very low range (20-268 mg/kg). Ethylbenzene, methyl tert-butyl ether, tert-amyl methyl ether, and lead were identified in one sampling point. Iron and zinc were found in all soil samples. There was no correlation between total petroleum hydrocarbons and any of the metals or between both metals. Only two out of four monitoring wells showed total petroleum hydrocarbons levels (1.4 and 66 mg/L, respectively). Regarding lead, all four monitored wells showed lead concentrations (0.043-0.15 mg/L). Results suggested that metal concentrations were not associated to petroleum contamination, but to iron scrap deposits placed over the soil; nevertheless more data is needed to make a clear conclusion. Health risk assessment showed that none of the evaluated contaminants represented a risk either for the on-site or the off-site receptors, since the hazardous quotients estimated did not exceed the acceptable values.

  19. Megacities air pollution problems: Mexico City Metropolitan Area critical issues on the central nervous system pediatric impact.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Kulesza, Randy J; Doty, Richard L; D'Angiulli, Amedeo; Torres-Jardón, Ricardo

    2015-02-01

    The chronic health effects associated with sustained exposures to high concentrations of air pollutants are an important issue for millions of megacity residents and millions more living in smaller urban and rural areas. Particulate matter (PM) and ozone (O3) concentrations close or above their respective air quality standards during the last 20 years affect 24 million people living in the Mexico City Metropolitan Area (MCMA). Herein we discuss PM and O3 trends in MCMA and their possible association with the observed central nervous system (CNS) effects in clinically healthy children. We argue that prenatal and postnatal sustained exposures to a natural environmental exposure chamber contribute to detrimental neural responses. The emerging picture for MCMA children shows systemic inflammation, immunodysregulation at both systemic and brain levels, oxidative stress, neuroinflammation, small blood vessel pathology, and an intrathecal inflammatory process, along with the early neuropathological hallmarks for Alzheimer and Parkinson's diseases. Exposed brains are briskly responding to their harmful environment and setting the bases for structural and volumetric changes, cognitive, olfactory, auditory and vestibular deficits and long term neurodegenerative consequences. We need to improve our understanding of the PM pediatric short and long term CNS impact through multidisciplinary research. Public health benefit can be achieved by integrating interventions that reduce fine PM levels and pediatric exposures and establishing preventative screening programs targeting pediatric populations that are most at risk. We fully expect that the health of 24 million residents is important and blocking pediatric air pollution research and hiding critical information that ought to be available to our population, health, education and social workers is not in the best interest of our children.

  20. Estimates of Late Pleistocene Runoff in Estancia Drainage Basin, Central New Mexico: Climate Assumptions vs. Model Results

    Science.gov (United States)

    Menking, K. M.; Anderson, R. Y.; Syed, K. H.; Shafike, N. G.

    2002-12-01

    The climatic conditions leading to highstands of "pluvial" Lake Estancia in central New Mexico have been a matter of considerable debate, resulting in a wide range of estimates for Pleistocene precipitation and temperature in the southwestern United States. Using a simple hydrologic balance approach, Leopold (1951) calculated that precipitation was 50% greater than modern based on the assumption that summer temperatures were 9 ° C colder while winter temperatures were unchanged. In contrast, Galloway (1970) called on temperature decreases of 10-11 ° C throughout the year and a reduction in mean annual precipitation of 14% to raise Lake Estancia to its highstand. In still another study, Brakenridge suggested that highstands could be achieved through no change in precipitation if monthly temperatures were reduced by 7-8 ° C. Experiments with 3 physically-based, continuous-time models to simulate surface runoff (USDA Soil and Water Assessment Tool), groundwater flow (MODFLOW with LAK2 package), and lake evaporation (lake energy balance model of Hostetler and Bartlein, 1990) indicate that none of these proposed full glacial climate scenarios could have produced a highstand lake. In particular, previous workers appear to have overestimated the reduction in evaporation rates associated with their proposed temperature changes, suggesting that using empirical relationships between modern air temperature and evaporation to predict late Pleistocene evaporation is problematic. Furthermore, model-determined reductions in lake evaporation are insufficient to allow for lake expansion as suggested by Galloway and Brakenridge. Even under Leopold's assumption that precipitation increased by 50%, modeled runoff appears to be insufficient to raise Lake Estancia more than a few meters above the lake floor.

  1. Plan of study to define hydrogeologic characteristics of the Madera Limestone in the east mountain area of central New Mexico

    Science.gov (United States)

    Rankin, D.R.

    1999-01-01

    The east mountain area of central New Mexico includes the eastern one-third of Bernalillo County and portions of Sandoval, Santa Fe, and Torrance Counties. The area covers about 320 square miles. The Madera Limestone, the principal aquifer in the east mountain area, is the sole source of water for domestic, municipal, industrial, and agricultural uses for many residents. Some water is imported from wells near Edgewood by the Entranosa Water Cooperative, which serves a population of approximately 3,300. The remaining population is served by small water systems that derive supplies locally or by individually owned domestic wells. The population of the east mountain area has increased dramatically over the past 20 years. In 1970, the population of the east mountain area was about 4,000. Demographic projections suggest that approximately 1,000 people per year are moving into the area, and with a growth rate of 3.0 percent the population will be 16,700 in 2000. Consequently, ground-water withdrawals have increased substantially over the past 20 years, and will continue to increase. Little is known about the flow characteristics and hydrogeologic properties of the Madera Limestone. This report describes existing information about the geologic and hydrologic framework and flow characteristics of the Madera Limestone, and presents a plan of study for data-collection activities and interpretive studies that could be conducted to better define the hydrogeologic characteristics of the Madera Limestone. Data-collection activities and interpretive studies related to the hydrogeologic components of the Madera Limestone are prioritized. Activities that are necessary to improve the quantification of a component are prioritized as essential. Activities that could add additional understanding of a component, but would not be necessary to improve the quantification of a component, are prioritized as useful.

  2. Revisions to the stratigraphic nomenclature of the Abiquiu Formation, Abiquiu and contiguous areas, north-central New Mexico

    Science.gov (United States)

    Maldonado, Florian; Kelley, Shari A.

    2009-01-01

    Stratigraphic studies and geologic mapping on the Abiquiu 7.5-min quadrangle have led to revision of the stratigraphic nomenclature for the Oligocene to Miocene Abiquiu Formation in north-central New Mexico. The Abiquiu Formation had previously been defined to include informal upper, middle (Pedernal chert member), and lower members. The basement-derived conglomeratic lower member in the northern Jemez Mountains and Abiquiu embayment is here redefined. We propose removing the "lower member" from the Abiquiu Formation because provenance of these coarse sediments is dramatically different than the volcaniclastic strata of the "upper member." Furthermore, we propose that the term "lower member of the Abiquiu Formation" be replaced with an existing unit name, the Ritito Conglomerate of Barker (1958), and that the name Abiquiu Formation be restricted to the volcaniclastic succession. The lower part of the Ritito Conglomerate in Arroyo del Cobre on the Abiquiu quadrangle is 47 m (155 ft) thick and is composed of arkosic conglomeratic beds interbedded with arkosic sands and siltstones. Clasts include, in descending order of abundance, Proterozoic quartzite, granite, metavolcanic rocks, quartz, schist, and gneiss and a trace of Mesozoic sandstone and Paleozoic chert. Clasts are predominantly of pebble and cobble size but range from granule to boulder size. Paleocurrent data collected in the Arroyo del Cobre area indicate that the Ritito Conglomerate was deposited by a south-flowing river system during the Oligocene, eroding Laramide highlands such as the Tusas Mountains to the northeast, which contain predominantly Proterozoic rocks. This depositional setting has also been suggested by previous workers. The middle member or Pedernal chert member is present both at the top of the Ritito Conglomerate and as lenses within the lower part of the Abiquiu Formation. This post-depositional diagenetic chert remains an informal unit called the Pedernal chert.

  3. Initial Time Of Two High Altitude Crater Lakes (Nevado De Toluca, Central Mexico Recorded In Subfossil Cladocera

    Directory of Open Access Journals (Sweden)

    Szeroczyńska Krystyna

    2015-12-01

    Full Text Available The objective of this study was the recognition and reconstruction of the origin of two high altitude lakes and the ecological conditions of their early existence based on subfossil Cladocera and chemical analyses. The study focused on the oldest lacustrine sediments from Lake Sol and Lake Luna, located in the crater of Volcano Nevado de Toluca (Central Mexico. The Nevado de Toluca crater developed approximately 12 ka yr BP. According to the literature, the volcano was last active approximately 3.3 ka yr BP, and the lakes developed after that eruption. The remains of nine Cladocera species were found in the bottom sediments of both lakes. The most dominant taxa were two endemic littoral species: Alona manueli and Iliocryptus nevadensis. The total frequency of Cladocera specimens in both of the sediment cores was very low. No Cladocera remains were recorded in the sediment layer at depths between 123–103 m from Lake Luna. The results of the lithological and geochemical analyses showed that this sediment layer was composed of allochthonous material, probably originating from slid down from the volcanic cone. This was suggested by the content of silica (up to 13%, iron (up to 12%, and titanium (up to 4%. The Cladocera remains recorded in the bottom sediments suggested that both reservoirs developed as freshwater lakes at the beginning of the sedimentation. The calibrated radiocarbon dates obtained for the bottom samples were 4040 to 3990 yr BP for Lake Luna (129 cm and 4485 to 4485 yr BP for Lake Sol (89 cm. The obtained ages were older than the dates of the last eruption, which occurred approximately 3300 yr BP. This result was likely related to the type of radiocarbon dated materials (charcoals.

  4. Effect of habitat disturbance on pollination biology of the columnar cactus Stenocereus quevedonis at landscape-level in central Mexico.

    Science.gov (United States)

    Rodríguez-Oseguera, A G; Casas, A; Herrerías-Diego, Y; Pérez-Negrón, E

    2013-05-01

    Stenocereus quevedonis ('pitire') is a columnar cactus endemic to central Mexico, grown for its edible fruit. Phenology, pollination biology and behaviour of flower visitors of this species were compared in six conserved and disturbed sites, hypothesising that: (i) pitire pollination is self-incompatible, requiring animal vectors; (ii) higher incidence of radiation on plants in cleared forest may lead to a higher number of flowers per pitire plant and longer blooming season, and disturbing and differential spatial availability of flower resources may determine differential attraction of pollinators to conserved and disturbed areas; (iii) if pitire pollination system is specialised, reproductive success would decrease with pollinator scarcity, or other species may substitute for main pollinators. In all sites, pitire reproduction started in January, flowering peak occurring in April, anthesis duration was 15 h and predominantly nocturnal (9 h), pollen was released at 23:00 h, nectar was produced throughout anthesis, and breeding system was self-incompatible. Flower production per plant was similar in disturbed and conserved sites, but flower availability was higher (because of higher tree density) and longer in disturbed sites. Pollination is nocturnal, the most frequent legitimate pollinator being the bat Leptonycteris yerbabuenae; diurnal pollination is rare but possible, carried out by bee species. Fruit and seed set in control and nocturnal pollination treatments at disturbed sites were higher than in conserved sites. Frequency of L. yerbabuenae visits was similar among site types, but more visits of complementary nocturnal and diurnal pollinators were recorded in disturbed sites, which could explain differences in reproductive success.

  5. Water-quality assessment of the Central Arizona Basins, Arizona and northern Mexico; environmental setting and overview of water quality

    Science.gov (United States)

    Cordy, Gail E.; Rees, Julie A.; Edmonds, Robert J.; Gebler, Joseph B.; Wirt, Laurie; Gellenbeck, Dorinda J.; Anning, David W.

    1998-01-01

    The Central Arizona Basins study area in central and southern Arizona and northern Mexico is one of 60 study units that are part of the U.S. Geological Survey's National Water-Quality Assessment program. The purpose of this report is to describe the physical, chemical, and environmental characteristics that may affect water quality in the Central Arizona Basins study area and present an overview of water quality. Covering 34,700 square miles, the study area is characterized by generally north to northwestward-trending mountain ranges separated by broad, gently sloping alluvial valleys. Most of the perennial rivers and streams are in the northern part of the study area. Rivers and streams in the south are predominantly intermittent or ephemeral and flow in response to precipitation such as summer thunderstorms. Effluent-dependent streams do provide perennial flow in some reaches. The major aquifers in the study area are in the basin-fill deposits that may be as much as 12,000 feet thick. The 1990 population in the study area was about 3.45 million, and about 61 percent of the total was in Maricopa County (Phoenix and surrounding cities). Extensive population growth over the past decade has resulted in a twofold increase in urban land areas and increased municipal water use; however, agriculture remains the major water use. Seventy-three percent of all water with drawn in the study area during 1990 was used for agricultural purposes. The largest rivers in the study area-the Gila, Salt, and Verde-are perennial near their headwaters but become intermittent downstream because of impoundments and artificial diversions. As a result, the Central Arizona Basins study area is unique compared to less arid basins because the mean surface-water outflow is only 528 cubic feet per second from a total drainage area of 49,650 square miles. Peak flows in the northern part of the study area are the result of snowmelt runoff; whereas, summer thunderstorms account for the peak flows in

  6. Persistence of Carbonate Platform Environments in Central Mexico during the Oceanic Anoxic Event 2: impact of the Carribean Plateau?

    Science.gov (United States)

    Bomou, Brahimsamba; Adatte, Thierry; Föllmi, Karl; Arnaud-Vanneau, Annie; Fleitmann, Dominik

    2010-05-01

    The Cenomanian-Turonian Oceanic Anoxic Event 2 is described as an interruption of normal pelagic sediment deposition by several distinct intervals of widespread oceanic anoxia (Schlanger & Jenkyns, 1976; Jenkyns, 1980; Arthur et al., 1990) characterized by black shales deposition coinciding with a positive shift in carbon isotope excursion. Some authors show a relationship between OAEs and massive volcanic events associated with the emplacement of large igneous provinces (LIPs) and sea floor spreading at mid-ocean ridges (Kuroda et al., 2007; Snow et al., 2005). High metal abundance anomalies recorded in pelagic sections (e.g. Pueblo, Colorado) coincide with the massive volcanism that built the Carribean plateau (around 93-94 Ma), associated with the onset of OAE 2 (Snow et al., 2005). Mort et al., (2007) demonstrate that the onset of the OAE 2 was triggered by a short-lived but significant increase in phosphorus burial. The bottom waters became anoxic and switched from being a P sink to a P source, sustaining the productivity in a positive feedback loop. However, the behaviour of phosphorus and trace metals at larger scale, in different paleogeography and paleodepht is still poorly known. The Axaxacualco and Baranca el Cañon sections, located at the Guerrero-Morelos carbonate platform in southern Mexico exhibit a fully correlateable d13C curves. In the distal part of the carbonate platform at Axaxacualco, the maximum d13C positive excursion coincides with oligotrophic carbonate platform environments supported by low concentrations in P and characterized by abundant and diversified benthic microfauna and rudists. The impact of OAE appears may be more significant in the proximal part of the carbonate platform at Barranca, characterized by the deposition of thick laminated microbialites indicative of mesotrophic conditions. The Morelos Carbonate platform with oligotrophic to mesotrophic conditions was persistent throughout the entire OAE2 in Central Mexico despite

  7. Study of tectonic layering motion and layering mineralization in the Tongling metallogenic cluster

    Institute of Scientific and Technical Information of China (English)

    吴淦国; 张达; 臧文拴

    2003-01-01

    Analysis of the deep tectonics and cover tectonic deformations shows that tectonic layering motion is a typical lithospheric characteristic in the Tongling area and the metallogenic belt of the middle-lower Yangtze. Controlling of the deep tectonosphere over the shallow-seated tectonosphere involves various grades of tectonic layering motions. Multi-layer, multi-grade, and multi-directional gliding tectonics are the specific modes of tectonic layering motions in the cover of the Tongling metallogenic cluster. The gliding tectonics developed based on S-shaped folds of the Indosinian, and was continuously active in the Yanshanian. They correspond to the deformation systems of the EW and NNE extensions. The control of tectonic layering motion acts against ore-forming processes, the different interlayer gliding belts can easily form different genetic-type deposits, and the ore-forming features of different parts of the same gliding layer are different. All of these characters are closely related to tectonic gliding mechanisms, tectonic compounding characteristics, features of metallogenic wall rocks, and types of ore-forming hydrothermal solutions.

  8. TECTONIC SETTING AND METALLOGENESIS OF THE PRINCIPAL SECTORS OF THE TETHYAN EURASIAN METALLOGENIC BELT

    Institute of Scientific and Technical Information of China (English)

    Slobodan; Jankovic

    2001-01-01

    Three global metallogenic belts were formed in the world during Mesozoic and post-Mesozoic times. Two of them are situated along the western and eastern Pacific margins, and the third one - the Tethyan Eurasian metallogenic belt (TEMB) is related to the domain of Eurasian plate and flanked on the south by the Afro-Arabian and Indian plates. The general tectonic evolution of the realm where the TEMB was formed is closely connected with the history of Tethys. The emplacement of ore deposits and the development of regional metallogenic units are related to a definitive time interval and to specific tectonic settings such as: (1) Intracontinental rifting along the northern margin of Gondwana and/or fragments already separated; (2) Oceanic environments (i.e. ophiolite complexes and ocean floor sediments) host podiform chromite deposits, volcano-sedimentary cupriferous pyrite deposits (Cyprus type), stratiform manganese deposits, and sporadically PGE deposits; (3) Subduction related settings involve mainly porphyry copper deposits, hydrothermal massive sulphide polymetallic deposits, and epithermal deposits. So far identified mineralization of porphyry copper exceeds in the TEMB over 100 million tons of copper metal; and(4) Collision and post-collision continent-continent setting includes deposits of lead-zinc, antimony, gold, in some sectors tin deposits, as well. The giant deposits of Li-pegmatite occur sporadically.The TEMB is almost a continuously mineralized belt, but within it, some sectors display specific features of tectonic settings, association of elements, minerals and morphogenetic types of mineralization.

  9. 秘鲁国金属矿成矿带%METALLOGENIC BELTS IN PERU

    Institute of Scientific and Technical Information of China (English)

    刘良根; 蒋科; 黄什

    2014-01-01

    秘鲁国金属成矿带划分依据为秘鲁境内的主要断层系统、有利成矿作用的岩性及矿化年代、已发现226个矿床(点)的地质特征和空间分布,共划分为24个成矿带。本文对每个成矿带的名称、分布、控矿地层、构造、岩浆岩及成矿时间逐一进行论述,并列出成矿带里典型矿床名称、资源量及品位情况。%Metallogenic belts in Peru are divided into 24 by major fault system, lithology favorable to metallogenic process, time of mineralization, geological features and spatial distribution of 226 known ore deposits (prospects) in the country. This paper discussed the name, distribution, ore-control stratum, structure, magmatic rock and metallogenic time of each belt and listed the name, resource and grade of typical ore deposit of the belts.

  10. Estimation of sediment residence times in subtropical highland catchments of central Mexico combining river gauging and fallout radionuclides

    Science.gov (United States)

    Evrard, Olivier; Némery, Julien; Gratiot, Nicolas; Duvert, Clément; Lefèvre, Irène; Ayrault, Sophie; Esteves, Michel; Bonté, Philippe

    2010-05-01

    Subtropical regions of the world are affected by intense soil erosion associated with deforestation, overgrazing and cropping intensification. This land degradation leads to important on-site (e.g. decrease in soil fertility) and off-site impacts (e.g. reservoir sedimentation, water pollution). This study determined the mean sediment residence times in soils and rivers of three catchments (3 - 12 km²) with contrasted land uses (i.e. cropland, forests, rangelands, extended gully networks) located in highlands of the transvolcanic belt of central Mexico. Calculations were based on rainfall and river gauging as well as on fallout radionuclide measurements (Be-7, Cs-137, Pb-210). Atmospheric deposition of Be-7 and Pb-210 was estimated based on the analysis of rainfall precipitated samples. Rainfall samples were collected all throughout the rainy season in order to take account of the temporal variations of the radionuclide fluxes. Furthermore, sampling of suspended sediment was conducted at the outlet of each catchment during most of the storms that occurred throughout the 2009 rainy season. Be-7, Cs-137 and Pb-210 concentrations of this sediment were determined by gamma-spectrometry. A two-box balance model was then used to estimate the sediment residence time and the inventory of radionuclides in the three selected catchments. This model subdivided each catchment into two boxes: (i) a "soil-box" characterised by low transport velocities and hence long radionuclide residence times and (ii) a "river-box" covering the river surface and its surroundings characterised by quicker exchanges and shorter radionuclide residence times. Input and output fluxes of sediment and radionuclides were taken into account in each box. Radioactive decay during the residence time of sediment was also considered. The mean residence time of sediment in soils ranged between 13,300 - 28,500 years. In contrast, sediment residence time in rivers was much shorter, fluctuating between 28 and 393

  11. Fine and coarse particulate matter chemical characterization in a heavily industrialized city in central Mexico during Winter 2003.

    Science.gov (United States)

    Vega, Elizabeth; Ruiz, Hugo; Martínez-Villa, Gerardo; Sosa, Gustavo; González-Avalos, Eugenio; Reyes, Elizabeth; García, José

    2007-05-01

    This paper presents the results of the first reported study on fine particulate matter (PM) chemical composition at Salamanca, a highly industrialized urban area of Central Mexico. Samples were collected at six sites within the urban area during February and March 2003. Several trace elements, organic carbon (OC), elemental carbon (EC), and six ions were analyzed to characterize aerosols. Average concentrations of PM with aerodynamic diameter of less than 10 microm (PM10) and fine PM with aerodynamic diameter of less than 2.5 microm (PM2.5) ranged from 32.2 to 76.6 [g m(-3) and 11.1 to 23.7 microg m(-3), respectively. OC (34%), SO4= (25.1%), EC (12.9%), and geological material (12.5%) were the major components of PM2.5. For PM10 geological material (57.9%), OC (17.3%), and SO4= (9.7%) were the major components. Coarse fraction (PM,, -PM2.5), geological material (81.7%), and OC (8.6%) were the dominant species, which amounted to 90.4%. Correlation analysis showed that sulfate in PM2.5 was present as ammonium sulfate. Sulfate showed a significant spatial variation with higher concentrations to the north resulting from predominantly southwesterly winds above the surface layer and by major SO2 sources that include a power plant and refinery. At the urban site of Cruz Roja it was observed that PM2.5 mass concentrations were similar to the submicron fraction concentrations. Furthermore, the correlation between EC in PM2.5 and EC measured from an aethalometer was r(2) = 0.710. Temporal variations of SO2 and nitrogen oxide were observed during a day when the maximum concentration of PM2.5 was measured, which was associated with emissions from the nearby refinery and power plant. From cascade impactor measurements, the three measured modes of airborne particles corresponded with diameters of 0.32, 1.8, and 5.6 microm.

  12. Quaternary volcanism in the Acambay graben, Mexican Volcanic Belt: Re-evaluation for potential volcanic danger in central Mexico

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Pedrazzi, D.; Lacan, P.; Roldan-Quintana, J.; Ortuňo, M.; Zuniga, R. R.; Laurence, A.

    2015-12-01

    The Mexican Volcanic Belt (MVB) is best known for the major active stratovolcanoes, such as Popocatépetl, Citlaltépetl and Colima. The most common stratovolcanoes in this province are modest-size cones with heights of 800 to 1000 m. Examples are Tequila, Sangangüey, Las Navajas, Culiacán, La Joya, El Zamorano, Temascalcingo and Altamirano; these last two were formed within the Acambay Graben in central MVB. The Acambay graben (20 x 70 km) is 100 km to the NW of Mexico City, with E-W trending seismically active normal faults; in particular the Acambay-Tixmadejé fault related to a mB =7 earthquake in 1912. Within the graben there are many volcanic structures, including calderas, domes, cinder cones and stratovolcanoes; Temascalcingo and Altamirano are the largest, with about 800 and 900 m heights, respectively. Temascalcingo is mostly composed of dacitic lavas and block and ash flow deposits. Includes a 3 x 2.5 km summit caldera and a magmatic sector collapse event with the associated debris avalanche deposit. 14C ages of 37-12 ka correspond to the volcano's latest phases that produced pyroclastic deposits. A major plinian eruption formed the San Mateo Pumice with an age of <20 Ka. Altamirano volcano is poorly studied; it is andesitic-dacitic, composed of lavas, pyroclastic flow deposits, and pumice fallouts. Morphologically is better preserved than Temascalcingo, and it should be younger. 14C ages of 4.0-2.5 ka were performed in charcoal within pyroclastic flow deposits that apparently were erupted from Altamirano. An undated 3 m thick pumice fallout on the flanks of Altamirano volcano could be also Holocene. It represents a major explosive event. The relatively young ages found in volcanic deposits within the Acambay graben raise the volcanic danger level in this area, originally thought as an inactive volcanic zone. The two major volcanoes, Temascalcingo and Altamirano, should be considered as dormant volcanoes that could restart activity at any time. We

  13. Comments on cladocerans of crater lakes of the Nevado de Toluca Volcano (Central Mexico), with the description of a new species, Alona manueli sp. nov.

    Science.gov (United States)

    Sinev, Artem Y; Zawisza, Edyta

    2013-01-01

    Cladoceran communities of two lakes of Nevado de Toluca Volcano, Central Mexico, were studied. A new species of Aloninae, Alona manueli sp. nov., is described. It was previously confused with Palearctic Alona intermedia Sars, 1862, but clearly differs from it in the morphology of postabdomen, head shield and head pores, and thoracic limbs. Position of Alona manueli sp. nov. within the genus is unclear, it did not belong to any species-group within Alona s. lato. Other species recorded in the studied lakes are Alona ossiani Sinev, 1998, Alonella pulchella Herrick, 1884, Chydorus belonging to sphaericus-group, Eurycercus longirostris Hann, 1982 and Pleuroxus cf. denticulatus Birge, 1879.

  14. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2014

    Science.gov (United States)

    Beman, Joseph E.

    2015-10-21

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is hydrologically defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when treatment and distribution of surface water from the Rio Grande through the San Juan-Chama Drinking Water Project began. A 20-percent population increase in the basin from 1990 to 2000 and a 22-percent population increase from 2000 to 2010 resulted in an increased demand for water.

  15. Magnetic Mineralogy as Indicator of dry Conditions in Lacustrine Sediments From Santa María del Oro, Nayarit, Central Mexico

    Science.gov (United States)

    Ortega, B.; Vazquez, G.; Rodriguez, A.

    2007-05-01

    Combined magnetic and geochemical analysis were conducted on laminated sediments from Santa Maria del Oro, a crater lake in Nayarit (Mexico), to build up a model of paleoenvironmental conditions for the late Holocene. The occurrence of a severe drought at the end of the archeological Classic period (100 - 900 AD) has been documented in sites of central Mexico (Zirahuen lake and Lerma basin), the Gulf of Mexico coast (Los Tuxtlas) and the Yucatan peninsula. The effects of this climatic event are considered to have stressed the social and political situation in the Yucatan area and other sites in Mesoamerica, and resulted in the "collapse" of the Maya civilization. Santa Maria del Oro sediments between ca. 600 - 1140 AD are characterized by repeated sequences of ocher silt laminae with high inorganic carbon content, authigenic siderite, and low concentration of SD magnetic minerals, followed upward by an increase of concentrations of fine grained SD and SP ferrimagnetic minerals in brown silt laminae. This sequence is considered to represent dissolution-precipitation cycles of magnetic minerals in low erosion, concentrated waters and anoxic water-sediment interface environments. Dissolution of magnetite occurs in reductive conditions, which are considered as warmer and dryer periods. Above the ocher silt, precipitation of fine grained magnetite occurs when conditions change to oxic environments. Ostracode C and O isotopy document a negative precipitation/evaporation balance during this time period.

  16. Epidemiology of central nervous system tumors at the Instituto Nacional de Neurología y Neurocirugía in Mexico City.

    Science.gov (United States)

    Velásquez-Pérez, L; Jiménez-Marcial, M E; Martínez-Martínez, J E

    2004-10-01

    The purpose of this study was to determine the frequency of different Central Nervous System Tumors (CNST) diagnosed at the Instituto Nacional de Neurología y Neurocirugía (National Institute of Neurology and Neurosurgery) from Mexico City over a 10-year period (1990 to 1999) by means of a hospital survey. This institute is a reference hospital that provides medical attention to a very high number of adult neurological patients every year (approximately 6,000 new patients per year besides emergency cases). From a total number of 2,041 CNST cases, we found that the most frequent tumors were those affecting the neuroepithelial tissue (32.8 %), followed by tumors of the anterior pituitary gland (26.2 %) and tumors of the meninges and similar tissues (24.1 %). In both, male and female patients the higher frequency of CNST was found in patients whose age ranged from 25 to 44 years, and CNST were slightly more frequent in women than in men. Most of the CNST patients lived in the southern districts of Mexico City, it could be because of the great number of people living in the southern districts of the city, or perhaps due to the presence of certain yet unidentified environmental carcinogenic substance in this area. Since CNST are among the more frequent malignant neoplasms, it is necessary to improve the registration system to include frequency, prevalence, incidence and mortality of these diseases in Mexico, in order to plan health policies like in developed countries.

  17. Nematodes parasites of the gray fox (Urocyon cinereoargenteus Schreber, 1775) in the seasonally dry tropical highlands of central Mexico.

    Science.gov (United States)

    Hernández-Camacho, Norma; Pineda-López, Raul; López-González, Carlos A; Jones, Robert W

    2011-06-01

    The gray fox (Urocyon cinereoargenteus Schreber, 1775) is the most abundant and opportunistic wild canid in Mexico. However, the parasites of this canid in Mexico are poorly known, and an intensive parasite survey is lacking. A survey of gray fox parasitological feces was conducted in El Cimatario National Park, a protected area representative of the seasonally dry, tropical highlands of Mexico. Feces were collected in six 1-km-length transects during the summer of 2003 and spring of 2004. The coproparasitoscopical survey registered nine species of nematodes, typical of wild and domestic canids such as Strongyloides stercoralis, Uncinaria stenocephala, Toxocara canis, Toxascaris leonina, Dioctophyme renale, Trichuris vulpis, Trichuris sp., and Capillaria sp. Ecological factors such as temperature and humidity appear to play a more important role in the establishment of these species of parasites in this protected area than the presence of domestic dogs.

  18. Low frequency (<1Hz) Large Magnitude Earthquake Simulations in Central Mexico: the 1985 Michoacan Earthquake and Hypothetical Rupture in the Guerrero Gap

    Science.gov (United States)

    Ramirez Guzman, L.; Contreras Ruíz Esparza, M.; Aguirre Gonzalez, J. J.; Alcántara Noasco, L.; Quiroz Ramírez, A.

    2012-12-01

    We present the analysis of simulations at low frequency (Valley of Mexico. Mexico's destructive earthquake history bolsters the need for a better understanding regarding the seismic hazard and risk of the region. The Mw=8.0 1985 Michoacan earthquake is among the largest natural disasters that Mexico has faced in the last decades; more than 5000 people died and thousands of structures were damaged (Reinoso and Ordaz, 1999). Thus, estimates on the effects of similar or larger magnitude earthquakes on today's population and infrastructure are important. Moreover, Singh and Mortera (1991) suggest that earthquakes of magnitude 8.1 to 8.4 could take place in the so-called Guerrero Gap, an area adjacent to the region responsible for the 1985 earthquake. In order to improve previous estimations of the ground motion (e.g. Furumura and Singh, 2002) and lay the groundwork for a numerical simulation of a hypothetical Guerrero Gap scenario, we recast the 1985 Michoacan earthquake. We used the inversion by Mendoza and Hartzell (1989) and a 3D velocity model built on the basis of recent investigations in the area, which include a velocity structure of the Valley of Mexico constrained by geotechnical and reflection experiments, and noise tomography, receiver functions, and gravity-based regional models. Our synthetic seismograms were computed using the octree-based finite element tool-chain Hercules (Tu et al., 2006), and are valid up to a frequency of 1 Hz, considering realistic velocities in the Valley of Mexico ( >60 m/s in the very shallow subsurface). We evaluated the model's ability to reproduce the available records using the goodness-of-fit analysis proposed by Mayhew and Olsen (2010). Once the reliablilty of the model was established, we estimated the effects of a large magnitude earthquake in Central Mexico. We built a kinematic rupture for a Mw=8.4 earthquake with the method of Liu et al. (2006) for the Guerrero Gap and computed the ground motion. We summarized our

  19. Structural Vulnerability Among Migrating Women and Children Fleeing Central America and Mexico: The Public Health Impact of “Humanitarian Parole”

    Science.gov (United States)

    Valdez, Elizabeth Salerno; Valdez, Luis A.; Sabo, Samantha

    2015-01-01

    Since October 2013, US Customs and Border Patrol has apprehended 15,979 families on the Southwest Border of the US. Daily, migrating women and children from Mexico and Central America that qualify for humanitarian parole are released from immigration detention to a humanitarian aid organization in Southern Arizona. After several days in detention facilities, these families arrive tired, hungry, dehydrated, and with minimal direction regarding their final destination, and adherence to the parameters of their parole. Project helping hands (PHHs) utilizes a network of volunteers to provide the women and children with food, water, clothing, hygiene products, hospitality, and legal orientation. The aim of this assessment was to document the experiences of families granted humanitarian parole through the lens of structural vulnerability. Here, we apply qualitative methods to elicit PHH lead volunteer perspectives regarding the migration experience of migrating families. Using inductive analysis, we found six major themes emerged from the qualitative data: reasons for leaving, experience on the journey, dehumanization in detention, family separation, vulnerability, and resiliency. These findings elucidate the different physical and psychological distresses that migrating families from Mexico and Central America experience before, during and after their arrival at the US–Mexico border. We posit that these distresses are a result of, or exacerbated by, structural vulnerability. Structural vulnerability has life-long health implications for a sub-population of young mothers and their children. The number of migrating families who have experienced traumatic events before and during their migration experience continues to expand and thus warrants consideration of mental health surveillance and intervention efforts for these families. More public health research is needed to better understand and combat the health challenges of this growing population. PMID:26157791

  20. 77 FR 29683 - Outer Continental Shelf (OCS) Consolidated Central Gulf of Mexico Planning Area Sale; 216/222

    Science.gov (United States)

    2012-05-18

    ..., Louisiana 70112. The lease sale will be held in the St. Charles Club Room on the second floor (Loge Level... Submission Deadline of 10:00 a.m. on Tuesday, June 19, 2012, the day before the lease sale. If bids are... Financial Responsibility Section, BOEM Gulf of Mexico Region, 1201 Elmwood Park Boulevard, New...

  1. Cost-effectiveness of breast cancer control strategies in Central America: the cases of Costa Rica and Mexico

    NARCIS (Netherlands)

    Niens, L.M.; Zelle, S.G.; Gutierrez-Delgado, C.; Rivera Pena, G.; Hidalgo Balarezo, B.R.; Rodriguez Steller, E.; Rutten, F.F.H.

    2014-01-01

    This paper reports the most cost-effective policy options to support and improve breast cancer control in Costa Rica and Mexico. Total costs and effects of breast cancer interventions were estimated using the health care perspective and WHO-CHOICE methodology. Effects were measured in disability-adj

  2. Cost-effectiveness of breast cancer control strategies in Central America: The cases of Costa Rica and Mexico

    NARCIS (Netherlands)

    L.M. Niëns (Laurens); S.G. Zelle (Sten); C. Gutiérrez-Delgado (Cristina); A. Peña (Alberto); B.R. Hidalgo Balarezo (Blanca Rosa); E.P. Steller (Erick); F.F.H. Rutten (Frans)

    2014-01-01

    markdownabstract__Abstract__ This paper reports the most cost-effective policy options to support and improve breast cancer control in Costa Rica and Mexico. Total costs and effects of breast cancer interventions were estimated using the health care perspective and WHO-CHOICE methodology. Effects w

  3. The Sanfandila earthquake sequence of 1998, Queretaro, Mexico: activation of an undocumented fault in the northern edge of central Trans-Mexican Volcanic Belt

    Science.gov (United States)

    Zúñiga, F. R.; Pacheco, J. F.; Guzmán-Speziale, M.; Aguirre-Díaz, G. J.; Espíndola, V. H.; Nava, E.

    2003-01-01

    A sequence of small earthquakes occurred in Central Mexico, at the northern edge of the Trans-Mexican Volcanic Belt (TMVB) in the State of Queretaro, during the first 3 months of 1998. Medium to large events in the continental regime of central Mexico are not common, but the seismic history of the region demonstrates that faults there are capable of generating destructive events. The sequence was analyzed using data from a temporary network with the goals of identifying the causative fault and its relation to regional tectonics. Employing a waveform inversion scheme adapted from a method used for regional studies, we found that the source mechanisms conform to the style of faulting (i.e. extension in the E-W direction) representative of the Taxco-San Miguel Allende Fault system. This system has been proposed as the southernmost extension of the Basin and Range (BR) Province. The spatial distribution of hypocenters and source mechanisms indicate that the seismogenic segment was a fault with an azimuth of approximately 334° with almost pure dip slip. Since events which occurred just south from this region show features which are consistent with TMVB tectonics (i.e. extension in an N-S direction), the sequence may mark the boundary between the TMVB and BR stress domains.

  4. Potential postwildfire debris-flow hazards—A prewildfire evaluation for the Jemez Mountains, north-central New Mexico

    Science.gov (United States)

    Tillery, Anne C.; Haas, Jessica R.

    2016-08-11

    and Rio Grande-Santa Fe watershed areas. No subbasins in this group have basin areas less than 1.0 km2. Many of these areas already had significant mass‑wasting episodes following the Las Conchas Fire in 2011. Other subbasins with integrated hazard index values in the top 2 percent are scattered throughout the Jemez River watershed area, including some subbasins in the interior of the Valles Caldera. Only a few subbasins in the top integrated hazard index group are in the Rio Chama watershed area.This prewildfire assessment approach is valuable to resource managers because the analysis of the debris-flow threat is made before a wildfire occurs, which facilitates prewildfire management, planning, and mitigation. In north‑central New Mexico, widespread watershed restoration efforts are being done to safeguard vital watersheds against the threat of catastrophic wildfire. This study was designed to help select ideal locations for the restoration efforts that could have the best return on investment.

  5. Evolution of Anthropogenic Pollution at the Top of the Regional Mixed Layer of the Central Mexico Plateau

    Science.gov (United States)

    Baumgardner, D.; Grutter, M.; Allan, J.; Ochoa, C.; Rappenglueck, B.; Russell, L. M.

    2009-04-01

    The concentrations of gases and properties of aerosol particles have been measured at the mountain site of Altzomoni approximately equidistant from Mexico City, Puebla and Cuernavaca, at an altitude of 4010 m. At this location there is a diurnal transition from local to regional mixed layer air whose properties depend on prevailing winds and larger scale circulation. Three days during March, 2006 have been evaluated during which time the synoptic scale air flow was from the east, southeast and southwest. In general the properties of gases and particles were similar when the regional mixed layer (RML) was below the research site, regardless of the direction of flow. When the RML reached the site, the highest concentrations of CO, O3 and aerosol particles were from the east, decreasing as the flow shifted to the southeast then to the southwest. The maximum concentration of condensation nuclei (CN) was greater than 25,000 cm-3 when winds were from the east. The highest mass concentrations of organic matter (OM), sulfate (SO4--), and Nitrate (NO3+) were 80, 4 and 8 μg m-3, at standard temperature and pressure in air from the east. The mass concentration of OM in the RML was greater than 70% of the total mass, regardless of the air mass origin. This compares to less than the 60% that has been reported for Mexico City. At night, the mass fraction of sulfate went up by a factor of ten from the daytime value when air arrived from the east. The relationship between the CO and OM suggests that the majority of the daytime OM is from biomass burning and at night it is from wood burning. Whereas the maximum CO at Altzomoni, 0.35 ppm, was approximately one tenth of the CO measured at the same time in the center of Mexico City, the maximum O3 of 120 ppb was approximately the same as in the city. The nighttime values of O3 was 60 ppb, indicating the presence of residual pollution. From these results we conclude that even though Mexico City is the second most populated city in the

  6. Evolution of anthropogenic pollution at the top of the regional mixed layer in the central Mexico plateau

    Science.gov (United States)

    Baumgardner, D.; Grutter, M.; Allan, J.; Ochoa, C.; Rappenglueck, B.; Russell, L. M.; Arnott, P.

    2009-01-01

    The concentrations of gases and properties of aerosol particles have been measured at the mountain site of Altzomoni approximately equidistant from Mexico City, Puebla and Cuernavaca, at an altitude of 4010 m. At this location there is a diurnal transition from local to regional mixed layer air whose properties depend on prevailing winds and larger scale circulation. Three days during March 2006 have been evaluated during which time the synoptic scale air flow was from the east, southeast and southwest. In general the properties of gases and particles were similar when the regional mixed layer (RML) was below the research site, regardless of the direction of flow. When the RML reached the site, the highest concentrations of CO, O3 and aerosol particles were from the east, decreasing as the flow shifted to the southeast then to the southwest. The maximum concentration of condensation nuclei (CN) was greater than 25×10-3 when winds were from the east. The highest mass concentrations of organic matter (OM), sulfate (SO4-), and Nitrate (NO3+ were 80, 4 and 8 μg m-3, at standard temperature and pressure in air from the east. The mass concentration of OM in the RML was greater than 70% of the total mass, regardless of the air mass origin. This compares to less than the 60% that has been reported for Mexico City. At night, the mass fraction of sulfate went up by a factor of ten from the daytime value when air arrived from the east. The relationship between the CO and OM suggests that the majority of the daytime OM is from biomass burning and at night it is from wood burning. Whereas the maximum CO at Altzomoni, 0.35 ppm, was approximately one tenth of the CO measured at the same time in the center of Mexico City, the maximum O3 of 120 ppb was approximately the same as in the city. The maximum nighttime values of O3 was 60 ppb, indicating the presence of residual pollution. From these results we conclude that even though Mexico City is the second most populated city in

  7. Volcanic settings and their reservoir potential: An outcrop analog study on the Miocene Tepoztlán Formation, Central Mexico

    Science.gov (United States)

    Lenhardt, Nils; Götz, Annette E.

    2011-07-01

    The reservoir potential of volcanic and associated sedimentary rocks is less documented in regard to groundwater resources, and oil and gas storage compared to siliciclastic and carbonate systems. Outcrop analog studies within a volcanic setting enable to identify spatio-temporal architectural elements and geometric features of different rock units and their petrophysical properties such as porosity and permeability, which are important information for reservoir characterization. Despite the wide distribution of volcanic rocks in Mexico, their reservoir potential has been little studied in the past. In the Valley of Mexico, situated 4000 m above the Neogene volcanic rocks, groundwater is a matter of major importance as more than 20 million people and 42% of the industrial capacity of the Mexican nation depend on it for most of their water supply. Here, we present porosity and permeability data of 108 rock samples representing five different lithofacies types of the Miocene Tepoztlán Formation. This 800 m thick formation mainly consists of pyroclastic rocks, mass flow and fluvial deposits and is part of the southern Transmexican Volcanic Belt, cropping out south of the Valley of Mexico and within the two states of Morelos and Mexico State. Porosities range from 1.4% to 56.7%; average porosity is 24.8%. Generally, permeabilities are low to median (0.2-933.3 mD) with an average permeability of 88.5 mD. The lavas are characterized by the highest porosity values followed by tuffs, conglomerates, sandstones and tuffaceous breccias. On the contrary, the highest permeabilities can be found in the conglomerates, followed by tuffs, tuffaceous breccias, sandstones and lavas. The knowledge of these petrophysical rock properties provides important information on the reservoir potential of volcanic settings to be integrated to 3D subsurface models.

  8. Cost-effectiveness of breast cancer control strategies in Central America: the cases of Costa Rica and Mexico.

    Science.gov (United States)

    Niëns, Laurens M; Zelle, Sten G; Gutiérrez-Delgado, Cristina; Rivera Peña, Gustavo; Hidalgo Balarezo, Blanca Rosa; Rodriguez Steller, Erick; Rutten, Frans F H

    2014-01-01

    This paper reports the most cost-effective policy options to support and improve breast cancer control in Costa Rica and Mexico. Total costs and effects of breast cancer interventions were estimated using the health care perspective and WHO-CHOICE methodology. Effects were measured in disability-adjusted life years (DALYs) averted. Costs were assessed in 2009 United States Dollars (US$). To the extent available, analyses were based on locally obtained data. In Costa Rica, the current strategy of treating breast cancer in stages I to IV at a 80% coverage level seems to be the most cost-effective with an incremental cost-effectiveness ratio (ICER) of US$4,739 per DALY averted. At a coverage level of 95%, biennial clinical breast examination (CBE) screening could improve Costa Rica's population health twofold, and can still be considered very cost-effective (ICER US$5,964/DALY). For Mexico, our results indicate that at 95% coverage a mass-media awareness raising program (MAR) could be the most cost-effective (ICER US$5,021/DALY). If more resources are available in Mexico, biennial mammography screening for women 50-70 yrs (ICER US$12,718/DALY), adding trastuzumab (ICER US$13,994/DALY) or screening women 40-70 yrs biennially plus trastuzumab (ICER US$17,115/DALY) are less cost-effective options. We recommend both Costa Rica and Mexico to engage in MAR, CBE or mammography screening programs, depending on their budget. The results of this study should be interpreted with caution however, as the evidence on the intervention effectiveness is uncertain. Also, these programs require several organizational, budgetary and human resources, and the accessibility of breast cancer diagnostic, referral, treatment and palliative care facilities should be improved simultaneously. A gradual implementation of early detection programs should give the respective Ministries of Health the time to negotiate the required budget, train the required human resources and understand possible

  9. Cost-effectiveness of breast cancer control strategies in Central America: the cases of Costa Rica and Mexico.

    Directory of Open Access Journals (Sweden)

    Laurens M Niëns

    Full Text Available This paper reports the most cost-effective policy options to support and improve breast cancer control in Costa Rica and Mexico. Total costs and effects of breast cancer interventions were estimated using the health care perspective and WHO-CHOICE methodology. Effects were measured in disability-adjusted life years (DALYs averted. Costs were assessed in 2009 United States Dollars (US$. To the extent available, analyses were based on locally obtained data. In Costa Rica, the current strategy of treating breast cancer in stages I to IV at a 80% coverage level seems to be the most cost-effective with an incremental cost-effectiveness ratio (ICER of US$4,739 per DALY averted. At a coverage level of 95%, biennial clinical breast examination (CBE screening could improve Costa Rica's population health twofold, and can still be considered very cost-effective (ICER US$5,964/DALY. For Mexico, our results indicate that at 95% coverage a mass-media awareness raising program (MAR could be the most cost-effective (ICER US$5,021/DALY. If more resources are available in Mexico, biennial mammography screening for women 50-70 yrs (ICER US$12,718/DALY, adding trastuzumab (ICER US$13,994/DALY or screening women 40-70 yrs biennially plus trastuzumab (ICER US$17,115/DALY are less cost-effective options. We recommend both Costa Rica and Mexico to engage in MAR, CBE or mammography screening programs, depending on their budget. The results of this study should be interpreted with caution however, as the evidence on the intervention effectiveness is uncertain. Also, these programs require several organizational, budgetary and human resources, and the accessibility of breast cancer diagnostic, referral, treatment and palliative care facilities should be improved simultaneously. A gradual implementation of early detection programs should give the respective Ministries of Health the time to negotiate the required budget, train the required human resources and understand

  10. Formation of sulphation deposits in cables in the electricity generation plant of Los Humeros geothermal field, Mexico; Sulfatacion de cables en la central geotermoelectrica Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Vergara Rangel, Agustin [Comision Federal de Electricidad, Perote, Veracruz (Mexico)

    2000-12-01

    In the construction of a central electrical generation plant using geothermal fluids, high quality standards are applied in all aspects of engineering. Los Humeros generation units were installed through trenches, ducts and trays according to norms for cables of control, force and power, specifically in point to point cables and connections. Performance of the power plant has been affected by electric momentary and sequence flaws due to problems of cable sulfating, which were solved by tinning the conductors. [Spanish] En la construccion de centrales generadoras de electricidad con fluidos geotermicos se aplican criterios de calidad de diseno en todos los aspectos de la ingenieria. En Los Humeros Puebla, se realizo la instalacion conforme a normas de cables de control, fuerza y potencia a traves de trincheras, ductos y charolas y especificamente en el cableado asi como en las conexiones de punta a punta. Todos estos aspectos son referidos a planos de los componentes y equipos electricos existentes en una central. Al paso del tiempo existieron fallas electricas momentaneas y secuenciales por el problema de sulfatacion en cables, los cuales fueron resueltos con el estanado de conductores.

  11. The giant South China Mesozoic low-temperature metallogenic domain: Reviews and a new geodynamic model

    Science.gov (United States)

    Hu, Ruizhong; Fu, Shanling; Huang, Yong; Zhou, Mei-Fu; Fu, Shaohong; Zhao, Chenghai; Wang, Yuejun; Bi, Xianwu; Xiao, Jiafei

    2017-04-01

    The South China Craton was formed by amalgamation of the Yangtze and Cathaysia Blocks during the Neoproterozoic. During the Mesozoic, voluminous granitic plutons and associated W-Sn polymetallic deposits were formed in the Cathaysia Block. The giant South China low-temperature metallogenic domain (LTMD) includes an area of ∼500,000 km2 in the Yangtze Block and is composed of the Chuan-Dian-Qian Pb-Zn, Youjiang Au-As-Sb-Hg and Xiangzhong Sb-Au metallogenic provinces. The Chuan-Dian-Qian Pb-Zn province contains numerous MVT Pb-Zn deposits, whereas the other two provinces are characterized by Carlin-type Au deposits and vein-type Sb, Hg and As deposits. These epigenetic deposits, which formed under low temperature conditions (∼100-250 °C), are typically hosted in sedimentary rocks and are locally controlled by faults and fractures. The deposits formed dominantly at 200-230 Ma and 130-160 Ma, corresponding to Indosinian (Triassic) and Yanshanian (Jurassic to Cretaceous) orogenies, respectively. Indosinian mineralization is recognized in all three provinces, but Yanshanian mineralization occurred only in the Youjiang and Xiangzhong provinces. The Indosinian orogeny, which involved collision of the Indochina Block with the South China Craton, resulted in circulation of basinal brines that leached ore-forming elements from adjacent sedimentary strata to form the Chuan-Dian-Qian Pb-Zn province. Deep-seated granitic magmas generated during this orogeny caused extensive circulation of meteoric water that mobilized ore-forming elements from the sedimentary strata to form the Carlin-type Au deposits in the Youjiang province, and the Sb-Au deposits in the Xiangzhong province. The Indosinian orogeny was the key factor in establishing the metallogenic framework of the LTMD. It produced widespread mineralization in the three metallogenic provinces, each of which has unique features reflecting differences in the nature and composition of the basement rocks. The Yanshanian

  12. Children’s Migration to the United States from Mexico and Central America: Evidence from the Mexican and Latin American Migration Projects

    Directory of Open Access Journals (Sweden)

    Katharine M. Donato

    2015-02-01

    Full Text Available In light of rising numbers of unaccompanied minors at the Mexico-US border in 2014, this article examines child migration from Mexico, Guatemala, El Salvador, Costa Rica, and Nicaragua. Using data from the Mexican and Latin American Migration Projects that permit us to go beyond simple descriptive analysis about children apprehended at the border, we investigate the extent to which children from these countries: (1 enter without legal authorization to do so; (2 are more likely to cross the border now than in the past; and (3 are tied to their parents’ migration. In theory, if immigration and refugee protections worked well for children and offered them legal pathways to reunify with their families, then we would expect low levels of unauthorized entry and no dramatic shifts over time. However, our examination of child migration shows that it is strongly linked to unauthorized entry, period of entry, and parents’ US experience.The findings show that the migration of children is closely linked to their parents’ migration history. Although the overall likelihood of a Mexican child making a first US trip is quite low, it is practically non-existent for children whose parents have no US experience. Thus, the increase in child migration from Central America, and the continued high levels of child migration from Mexico result from widespread migration networks and the United States’ long-standing reliance on the children’s parents as immigrant workers. The findings suggest that these children need protection in the form of family reunification and permanent legal status.

  13. Morphological, morphometrical and molecular (CO1 and ITS) analysis of the rotifer Asplanchna brightwellii from selected freshwater bodies in Central Mexico.

    Science.gov (United States)

    Jiménez-Contreras, Jorge; Sarma, S S S; Calderón-Torres, Marissa; Nandini, S

    2013-11-01

    We evaluated different strains of the rotifer Asplanchna brightwellii collected from central Mexico using morphology, morphometry and molecular tools (CO1 and ITS). Three distinct clonal populations from each of the 3 regions (Mexico City, State of Mexico and State of Guerrero) were established under laboratory conditions. For a given waterbody, morphometric comparisons within the populations of A. brightwellii showed almost stable measurements of trophi and with no statistically significant differences among them (p > 0.05). However, asplanchnid body length and width as well as the cyst diameter varied significantly depending on the waterbody from which A. brightwellii was collected. The smallest adults (about 700 microm) were from Valerio Trujano lake (Guerrero State) samples while the largest were from Xochimilco lake. Similar tendencies were reflected in the diameter of resting eggs. In addition, morphologically the cysts of A. brightwellii from the three waterbodies showed slightly different pattern. The number of globular structures on the surface of cysts was smaller for Valerio Trujano strain, while these were larger and less numerous for both Xochimilco and Zumpango strains. The ITS region tree displayed two groups Xochimilco and Valerio Trujano -Zumpango, this analysis did not reflect the morphological grouping; on the contrary the CO1 gene tree separated the populations according to morphological clusters and location (Xochimilco, Valerio Trujano and Zumpango lakes). When the tree was built using the combination of both ITS and CO1 sequences, the phylogenetic relationships observed on CO1 gene were consistent; but showed differences with the relationships observed on ITS region tree (only two groups).

  14. Distribution and abundance of cetaceans in the north-central and western Gulf of Mexico. Final report. Volume 1. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.W.; Fargion, G.S.

    1996-05-24

    The purpose of the study was to determine the distribution and abundance of cetaceans in areas potentially affected by future oil and gas activities along the continental slope of the north-central and western Gulf of Mexico. This 3.75 year project commenced 1 October 1991 and finished 15 July 1995. The study area was bounded by the Florida-Alabama border, the Texas-Mexico border, and the 100 m and 2,000 m isobaths. Cetacean distribution and abundance were determined from seasonal aerial and shipboard visual surveys and shipboard acoustic surveys. In addition, hydrographic data were collected in situ and by satellite remote sensing to characterize cetacean habitat. Finally, tagging and tracking of sperm whales using satellite telemetry was attempted. This volume summarizes the results of the study. Cetaceans were observed throughout the study area during all four seasons. Nineteen species were identified, including two species (melon-headed whales and Fraser`s dolphins) previously thought to be rare in the Gulf. Pantropical spotted dolphins, bottlenose dolphins, clymene dolphins, striped dolphins, Atlantic spotted dolphins, and melon-headed whales were the most common small cetaceans and the sperm whale was the most common large cetacean. The mean annual abundance for all cetaceans was estimated to be 19,198. Although the study area had complex and dynamic oceanography, bottom depth was the only environmental variable which correlated to cetacean distribution.

  15. Distribution and abundance of cetaceans in the north-central and western Gulf of Mexico. Final report. Volume 2. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.W.; Fargion, G.S.

    1996-05-24

    The purpose of the study was to determine the distribution and abundance of cetaceans in areas potentially affected by future oil and gas activities along the continental slope of the north-central and western Gulf of Mexico. This 3.75 year project commenced 1 October 1991 and finished 15 July 1995. The study area was bounded by the Florida-Alabama border, the Texas-Mexico border, and the 100 m and 2,000 m isobaths. Cetacean distribution and abundance were determined from seasonal aerial and shipboard visual surveys and shipboard acoustic surveys. In addition, hydrographic data were collected in situ and by satellite remote sensing to characterize cetacean habitat. Finally, tagging and tracking of sperm whales using satellite telemetry was attempted. This volume summarizes the results of the study. Cetaceans were observed throughout the study area during all four seasons. Nineteen species were identified, including two species (melon-headed whales and Fraser`s dolphins) previously thought to be rare in the Gulf. Pantropical spotted dolphins, bottlenose dolphins, clymene dolphins, striped dolphins, Atlantic spotted dolphins, and melon-headed whales were the most common small cetaceans and the sperm whale was the most common large cetacean. The mean annual abundance for all cetaceans was estimated to be 19,198. Although the study area had complex and dynamic oceanography, bottom depth was the only environmental variable which correlated to cetacean distribution.

  16. Distribution and abundance of cetaceans in the north-central and western Gulf of Mexico. Final report. Volume 3. Appendix C. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.W.; Fargion, G.S.

    1996-05-24

    The purpose of the study was to determine the distribution and abundance of cetaceans in areas potentially affected by future oil and gas activities along the continental slope of the north-central and western Gulf of Mexico. This 3.75 year project commenced 1 October 1991 and finished 15 July 1995. The study area was bounded by the Florida-Alabama border, the Texas-Mexico border, and the 100 m and 2,000 m isobaths. Cetacean distribution and abundance were determined from seasonal aerial and shipboard visual surveys and shipboard acoustic surveys. In addition, hydrographic data were collected in situ and by satellite remote sensing to characterize cetacean habitat. Finally, tagging and tracking of sperm whales using satellite telemetry was attempted. Appendix C Part 2 contains the hydrogrpahic data collected during TIO Cruises 5-7. Cetaceans were observed throughout the study area during all four seasons. Nineteen species were identified, including two species (melon-headed whales and Fraser`s dolphins) previously thought to be rare in the Gulf. Pantropical spotted dolphins, bottlenose dolphins, clymene dolphins, striped dolphins, Atlantic spotted dolphins, and melon-headed whales were the most common small cetaceans and the sperm whale was the most common large cetacean. The mean annual abundance for all cetaceans was estimated to be 19,198. Although the study area had complex and dynamic oceanography, bottom depth was the only environmental variable which correlated to cetacean distribution.

  17. Distribution and abundance of cetaceans in the north-central and western Gulf of Mexico. Final report. Volume 3. Appendix C. Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.W.; Fargion, G.S.

    1996-05-24

    The purpose of the study was to determine the distribution and abundance of cetaceans in areas potentially affected by future oil and gas activities along the continental slope of the north-central and western Gulf of Mexico. This 3.75 year project commenced 1 October 1991 and finished 15 July 1995. The study area was bounded by the Florida-Alabama border, the Texas-Mexico border, and the 100 m and 2,000 m isobaths. Cetacean distribution and abundance were determined from seasonal aerial and shipboard visual surveys and shipboard acoustic surveys. In addition, hydrographic data were collected in situ and by satellite remote sensing to characterize cetacean habitat. Finally, tagging and tracking of sperm whales using satellite telemetry was attempted. Appendix C Part 1 contains the hydrographic data collected during TIO Cruises 1-4. Cetaceans were observed throughout the study area during all four seasons. Nineteen species were identified, including two species (melon-headed whales and Fraser`s dolphins) previously thought to be rare in the Gulf. Pantropical spotted dolphins, bottlenose dolphins, clymene dolphins, striped dolphins, Atlantic spotted dolphins, and melon-headed whales were the most common small cetaceans and the sperm whale was the most common large cetacean. The mean annual abundance for all cetaceans was estimated to be 19,198. Although the study area had complex and dynamic oceanography, bottom depth was the only environmental variable which correlated to cetacean distribution.

  18. Distribution and abundance of cetaceans in the north-central and western Gulf of Mexico. Final report. Volume 3. Appendix B

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-24

    The purpose of the study was to determine the distribution and abundance of cetaceans in areas potentially affected by future oil and gas activities along the continental slope of the north-central and western Gulf of Mexico. This 3.75 year project commenced 1 October 1991 and finished 15 July 1995. The study area was bounded by the Florida-Alabama border, the Texas-Mexico border, and the 100 m and 2,000 m isobaths. Cetacean distribution and abundance were determined from seasonal aerial and shipboard visual surveys and shipboard acoustic surveys. In addition, hydrographic data were collected in situ and by satellite remote sensing to characterize cetacean habitat. Finally, tagging and tracking of sperm whales using satellite telemetry was attempted. Appendix B contains the hydrographic data collected during all four NMFS-SEFSC cruises. Cetaceans were observed throughout the study area during all four seasons. Nineteen species were identified, including two species (melon-headed whales and Fraser`s dolphins) previously thought to be rare in the Gulf. Pantropical spotted dolphins, bottlenose dolphins, clymene dolphins, striped dolphins, Atlantic spotted dolphins, and melon-headed whales were the most common small cetaceans and the sperm whale was the most common large cetacean. The mean annual abundance for all cetaceans was estimated to be 19,198. Although the study area had complex and dynamic oceanography, bottom depth was the only environmental variable which correlated to cetacean distribution.

  19. Subsoil TPH and other petroleum fractions-contamination levels in an oil storage and distribution station in north-central Mexico.

    Science.gov (United States)

    Iturbe, Rosario; Flores, Carlos; Flores, Rosa Ma; Torres, Luis G

    2005-12-01

    Many oil industry related sites have become contaminated due to the activities characteristic of this industry, such as oil exploration and production, refining, and petro-chemistry. In Mexico, reported hydrocarbon spills for the year 2000 amounted to 185203, equivalent to 6252 tons (PEMEX, 2000). The first step for the remediation of these polluted sites is to assess the size and intensity of the oil contamination affecting the subsoil and groundwater, followed by a health risk assessment to establish clean up levels. The aim of this work was to characterize the soil and water in a north-central Mexico Oil Storage and Distribution Station (ODSS), in terms of TPHs, gasoline and diesel fractions, BTEX, PAHs, MTBE, and some metals. Besides, measurements of the explosivity index along the ODSS were made and we describe and discuss the risk health assessment analysis performed at the ODSS, as well as the recommendations arising from it. Considering soils with TPH concentrations higher than 2000 mg kg(-1), the contaminated areas corresponding to the railway zone is about 12776.5 m2, to the south of the storage tanks is about 6558 m2, and to the south of the filling tanks is about 783 m2. Total area to be treated is about 20107 m2 (volume of 20107 m3), considering 1m depth.

  20. Evolution of anthropogenic pollution at the top of the regional mixed layer in the central Mexico plateau

    Directory of Open Access Journals (Sweden)

    D. Baumgardner

    2009-01-01

    Full Text Available The concentrations of gases and properties of aerosol particles have been measured at the mountain site of Altzomoni approximately equidistant from Mexico City, Puebla and Cuernavaca, at an altitude of 4010 m. At this location there is a diurnal transition from local to regional mixed layer air whose properties depend on prevailing winds and larger scale circulation. Three days during March 2006 have been evaluated during which time the synoptic scale air flow was from the east, southeast and southwest. In general the properties of gases and particles were similar when the regional mixed layer (RML was below the research site, regardless of the direction of flow. When the RML reached the site, the highest concentrations of CO, O3 and aerosol particles were from the east, decreasing as the flow shifted to the southeast then to the southwest. The maximum concentration of condensation nuclei (CN was greater than 25×10−3 when winds were from the east. The highest mass concentrations of organic matter (OM, sulfate (SO4, and Nitrate (NO3+ were 80, 4 and 8 μg m−3, at standard temperature and pressure in air from the east. The mass concentration of OM in the RML was greater than 70% of the total mass, regardless of the air mass origin. This compares to less than the 60% that has been reported for Mexico City.

    At night, the mass fraction of sulfate went up by a factor of ten from the daytime value when air arrived from the east. The relationship between the CO and OM suggests that the majority of the daytime OM is from biomass burning and at night it is from wood burning.

    Whereas the maximum CO at Altzomoni, 0.35 ppm, was approximately one tenth of the CO measured at the same time in the center of Mexico City, the maximum O3 of 120 ppb was approximately the same as in the city. The maximum nighttime values of O3 was 60 ppb

  1. “He Beat You in the Blood”: Knowledge and Beliefs about the Transmission of Traits among Latinos from Mexico and Central America

    Science.gov (United States)

    Sandberg, Joanne C.; Rodriguez, Guadalupe; Howard, Timothy D.; Quandt, Sara A.; Arcury, Thomas A.

    2016-01-01

    Purpose Genomic literacy is becoming increasingly important. Knowledge about how Latinos from Mexico and Central America (MCA) think and speak about how traits are shared by family members is needed. Methods Semi-structured in-depth interviews were conducted with 16 MCA Latino men and women. Interviews elicited detailed information about participant beliefs and knowledge about intergenerational trait transmission, genes and genetics. Transcripts were systematically analyzed. Results Most participants had familiarity with the role of genes. Knowledge about gene function was limited. Participants used “blood talk” to discuss awareness that traits are transmitted between generations and to express that blood itself plays a crucial role often, but not necessarily, in conjunction with genes or DNA to transmit traits. Conclusion Health educators need to directly address potential confusion about blood’s role in the transmission of traits. Culturally and linguistically appropriate materials are needed to present genetic and genomic information to MCA Latinos. PMID:26660317

  2. Resource Assessment of the In-Place and Potentially Recoverable Deep Natural Gas Resource of the Onshore Interior Salt Basins, North Central and Northeastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini; Donald A. Goddard

    2004-10-28

    The objectives of the study are: to perform resource assessment of the in-place deep (>15,000 ft) natural gas resource of the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas through petroleum system identification, characterization and modeling and to use the petroleum system based resource assessment to estimate the volume of the in-place deep gas resource that is potentially recoverable and to identify those areas in the interior salt basins with high potential to recover commercial quantities of the deep gas resource. The principal research effort for Year 1 of the project is data compilation and petroleum system identification. The research focus for the first nine (9) months of Year 1 is on data compilation and for the remainder of the year the emphasis is on petroleum system identification.

  3. Fiesta! Mexico and Central America: A Global Awareness Program for Children in Grades 2-5. Bridges between Nations Series.

    Science.gov (United States)

    Linse, Barbara; Judd, Dick

    Mexican and Central American cultures are a blend of Native American influences and Spanish traditions and religions. These are seen in aspects of Mexican and Central American celebrations. This book explores those celebrations through activities in art, folk and classical music, dances and fiestas. The book is organized into two sections to…

  4. Geochemistry of soils along a transect from Central Mexico to the Pacific Coast: a pilot study for continental-scale geochemical mapping

    Science.gov (United States)

    Chiprés, J.A.; de la Calleja,; Tellez, J.I.; Jiménez, F.; Cruz, Carlos; Guerrero, E.G.; Castro, J.; Monroy, M.G.; Salinas, J.C.

    2009-01-01

    The Mexican Geological Survey (SGM), the National Institute of Statistics, Geography and Informatics (INEGI) and the Autonomous University of San Luis Potosi (UASLP) have established a multidisciplinary team with the objective of creating a national program of geochemical mapping of soils in Mexico. This is being done as part of the North American Soil Geochemical Landscapes Project in partnership with the US Geological Survey and the Geological Survey of Canada. As the first step, a pilot study was conducted over a transect that extends from the Mexico–US border near Ciudad Juarez in the north to the Pacific Ocean in the south. This pilot transect was conducted in two phases, and this paper presents results from the first phase, which sampled soils at about a 40-km spacing along a 730-km transect beginning in Central Mexico and ending at the Pacific Coast. Samples were collected from the A and C horizons at each site and 60 elements were analyzed. This pilot study demonstrates that geochemical mapping based on a 40-km spacing is adequate to identify broad-scale geochemical patterns. Geologic influence (i.e., soil parent material) was the most important factor influencing the distribution of elements along the transect, followed by the influence of regional mineralization. The study also showed that influence by human activities over the transect is minimal except possibly in large mining districts. A comparison of element abundance in the A horizon with the environmental soil guidelines in Mexico showed that the natural concentrations of the studied soils were lower than the established threshold for soil restoration with the exception of V and As. The former had a median value (75 mg/kg) approximately equal to the value established in Mexico for soil restoration in agricultural and residential lands (78 mg/kg), and the latter had three values higher than the 22 mg/kg threshold for soil restoration in agricultural and residential lands. These cases demonstrate

  5. Extreme changes to barrier islands along the central Gulf of Mexico coast during Hurricane Katrina: Chapter 5C in Science and the storms-the USGS response to the hurricanes of 2005

    Science.gov (United States)

    Sallenger, Asbury; Wright, Wayne; Lillycrop, Jeff; Howd, Peter; Stockdon, Hilary; Guy, Kristy K.; Morgan, Karen

    2007-01-01

    Hurricane Katrina caused extreme changes to the barrier islands of the central Gulf of Mexico coast. Dauphin Island, Ala., migrated landward and stranded the remains of its oceanfront row homes in the sea. Chandeleur Islands, La., were completely stripped of their sand, leaving only marshy outcrops in the storm's wake.

  6. Landscape evolution of the graben of Puerto Vallarta (west-central Mexico) using the analysis of landforms and stream long profiles

    Science.gov (United States)

    Castillo, Miguel

    2017-01-01

    The analysis of landforms and stream long profiles are useful tools that can provide information about the tectonic activity in the landscape. The west-central portion of Mexico is a region that is mostly dominated by an extensional tectonics initiated in the Miocene and continuing in the Quaternary, where there has also been a vast emission of volcanic products. Of particular importance is the graben of Puerto Vallarta which was formed during the extensional activity that opened the Gulf of California in the Miocene. Nevertheless, the geomorphology and landscape evolution of this structure has not been studied in detail. Here I present a study of the rivers, landforms and topography of Puerto Vallarta graben in order to assess its evolution, focusing on the evidences of its initial phase of formation. The geomorphological map elaborated in this study reveals the presence of lava flows and volcanic structures in the eastern sector of the graben. Here it is proposed that this volcanism occurred during the formation of the graben in the Miocene, nevertheless, radiometric dating of lavas is still required to determine the precise timing of this event. Analysis of stream long profiles confirms that knickpoints are propagating in the fluvial network at a rate of ∼0.07 to ∼0.7 mm yr-1 and these were probably triggered by a drop in the base-level of rivers during the graben formation. The rates of knickpoint retreat in the graben of Puerto Vallarta are slightly lower than those observed in other recent (Quaternary) tectonic areas, however, the migration rates of the graben of Puerto Vallarta were probably higher at the onset of the faulting. Here the analysis of landforms and stream long profiles were useful to elucidate one part of the evolution of the graben of Puerto Vallarta. This study emphasizes the importance of incorporating the tectonic geomorphology in future studies of the extensional zones of west-central Mexico.

  7. Measurement of Metallogenic Depth and Deep Second Enrichment Belt Forecasting in Jiaodong Gold Deposit

    Institute of Scientific and Technical Information of China (English)

    Guo Tao; Lü Guxian

    2004-01-01

    The depth is important for ore finding in Jiaodong gold deposit. However, many geologists are still discussing how to confirm the depth for the tectonic and metallogenesis formation. The authors of this paper propose a new method-the correction of metallogenic depth via its structure to calculate the depth. This method, based on the crust rock in a solid stress state, emphasizes the elastic pattern rather than the static-fluid pattern. In addition, this method is more appropriate to the actual situation in the crust than the method of weight/special weight. The authors of this paper illustrating, with the Jiaodong gold deposit as an example, the metallogenic depth correction via structure conclude that the depth of the most deposits, lower than 4-6 km, is often 2.5 km. Therefore, the authors suggest that there exists a second enrichment belt and that ore resources are more potential at the belt of Jiaodong area. These results have been demonstrated by years of exploration.

  8. Metallogenic Systems on the Paleocontinental Margin of the North China Craton

    Institute of Scientific and Technical Information of China (English)

    ZHAI Yusheng; DENG Jun; TANG Zhongli; XIAO Rongge; SONG Honglin; PENG Runmin; SUN Zhongshi; WANG Jianping

    2004-01-01

    The North China Craton (NCC) is one of the largest blocks composing the continent. Different types of continental margins well developed around the NCC, along with lots of metallogenic systems of different metals and different times. Based on the study on the structural evolution of the NCC, the authors made a new division of tectonic units of the NCC. Through an analysis of the data of 1:25000 geochemical survey on stream sediments, regional geochemical features of main ore-forming elements including Au, Ag, Cu, Pb, Zn, W, Ni, Co and Mo of the NCC are discussed in the paper. Then different metallogenic systems and their forming processes and geodynamics are discussed in detail. At last, temporal and spatial distribution regularities are summarized and ten favorable ore-control factors on the paleocontinental margins are put forward, including (1) abundance of ore sources; (2) rendezvous of ore-forming fluids; (3) high thermo-dynamic anomaly; (4) remarkable Earth crust-mantle interaction; (5) cluster of macroscopic structures and their long activities; (6) diversity of ore-forming environments; (7) long geohistory; (8) multiforms of critical transitional ore-forming mechanisms; (9) multi-staged and superimposed ore-formation; and (10) suitable preservation condition.

  9. Out of operation in simultaneous way of the two reactors of nucleoelectric central of Laguna Verde(Mexico); Fuera de operacion, de maneira simultanea, los dos reactores de la central nucleoelectrica de Laguna Verde (Mexico)

    Energy Technology Data Exchange (ETDEWEB)

    Mar, Bernardo Salas, E-mail: salasmarb@yahoo.com.mx [Universidad Nacional Autonoma de Mexico, D.F. (Mexico). Facultad de Ciencias. Departamento de Fisica

    2013-11-01

    The two nuclear reactors that Mexico has in the Laguna Verde Nuclear Power Plant, were out of operation simultaneously in September 2012. First it was reported that one of the reactors had problems with the diesel generator, while the other had problems with the nuclear fuel reloading. The day after it was reported a problem related to sediment in the Obra de Toma, place the plant feeds seawater to cool the condenser the depth to which it must operate is 6 meters, with the current level of 1.5 meters, causing a lack of cooling water. Finally it was reported the cause of the suspension of operations, the cracks in jet pumps in both reactors. It is described a brief analysis of these opinions. The reactors are of cooling water of General Electric (BWR-5) and generate 1640 MWe each one.

  10. Cut and carry vs. grazing of cultivated pastures in small-scale dairy systems in the central highlands of Mexico

    Directory of Open Access Journals (Sweden)

    Paola Estefania Pincay-Figueroa

    2016-12-01

    Full Text Available Small-scale dairy systems are an option to alleviate poverty and contribute up to 37% of milk production in Mexico; however high costs affect their economic sustainability. Since grazing may reduce feeding costs, a participatory on farm experiment was undertaken to compare animal performance and feeding costs of the traditional cut-and-carry strategy or grazing cultivated pastures, during the dry season in the highlands of Mexico. Pastures of perennial and annual ryegrasses with white clover were utilised, complemented with maize silage and commercial concentrate. Five dairy cows were assigned to each strategy. The experiment ran for 12 weeks, recording weekly milk yields and fat and milk protein content; live-weight and body condition score every 14 days. Analysis was as a split-plot design. The adjusted (covariance mean milk yield was 18.78 kg/cow/day with no significant differences (P>0.05 between treatments, and no significant differences for live-weight or body condition score. There were no significant differences for milk fat (P>0.05, but there were for protein in milk (P

  11. Origin and Superposition Metallogenic Model of the Sandstone-type Uranium Deposit in the Northeastern Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    LI Ziying; CHEN Anping; FANG Xiheng; OU Guangxi; XIA Yuliang; SUN Ye

    2008-01-01

    This paper deals with the metallogenic model of the sandstone type uranium deposit in thenortheastern Ordos Basin from aspects of uranium source, migration and deposition. A superpositionmetallogenie model has been established due to complex uranium mineralization processes withsuperposition of oil-gas reduction and thermal reformation.

  12. Slab Detachment, Flat Subduction and Slab Rollback in Central Mexico: Fitting the Neogene Evolution of the Trans-Mexican Volcanic Belt into the History and Dynamics of Subduction

    Science.gov (United States)

    Ferrari, L.

    2001-12-01

    I present a comparative analysis of the volcanic record of the Trans-Mexican Volcanic Belt (TMVB) and the plate tectonic history since 16 Ma in central Mexico that has important implications for the dynamic of the Cocos-Rivera subduction system. The TMVB volcanism has occurred in episodes characterized by across-arc and along strike variation and/or migration. In its first stage (16 to 10 Ma) the TMVB consisted of a broad andesitic arc emplaced between Long. 102° and 97° 30' (central Mexico). During this period volcanism was absent in the western and eastern TMVB. Between 11 and 6 Ma a voluminous mafic volcanism was emplaced to the northof the previous arc with ages progressively younger from west (Tepic-Guadalajara) to east (Queretaro-Hidalgo). Large calderas and silicic dome complexes developed in latest Miocene and early Pliocene (7.5 to 3.5 Ma) west of the Taxco-San Miguel de Allende fault system (TSMA). East of the TSMA a volcanic gap is clearly observed between ~9 and 3.5 Ma. In the western TMVB small amount of lavas with an intra-plate affinity started to be emplaced since 5 Ma. At the same time the volcanic front migrated to the south by about 70 km. East of the TSMA volcanism resumed at about 3.5 Ma in the Mexico City region and at the end of Pliocene in the eastern TMVB (excluding the Palma Sola area). In the Toluca - Mexico City area the volcanic front migrated trenchward in the Quaternary. No southward migration of the volcanic front is observed in the eastern TMVB. The Middle Miocene volcanism represent a "normal" volcanic arc developed after a gap of ~15 Ma following the formation of the Acapulco trench. I propose that the following unusual volcanic evolution was controlled by the detachment of the deeper part of the Cocos slab and the resulting variation in slab inclination. Slab must have detached after 12.5 following the end of subduction off Baja California. This is a kinematic-dynamic requirement, also supported by the fact that the present

  13. Paleoecological studies at Lake Patzcuaro on the west-central Mexican Plateau and at Chalco in the basin of Mexico

    Science.gov (United States)

    Watts, W.A.; Bradbury, J.P.

    1982-01-01

    A 1520-cm sediment core from Lake Patzcuaro, Michoacan, Mexico, is 44,000 yr old at the base. All parts of the core have abundant pollen of Pinus (pine), Alnus (alder), and Quercus (oak) with frequent Abies (fir). The interval dated from 44,000 to 11,000 yr ago has a homogeneous flora characterized by abundant Juniperus (juniper) pollen and frequent Artemisia (sagebrush). It is believed to represent an appreciably drier and colder climate than at present. The Holocene at Lake Patzcuaro is characterized by a moderate increase in Pinus pollen and the loss of Juniperus pollen, as the modern type of climate succeeded. Alnus was abundant until about 5000 yr ago; its abrupt decrease with the first appearance of herbaceous weed pollen may reflect the cutting of lake-shore and stream-course alder communities for agricultural purposes, or it may simply reflect a drying tendency in the climate. Pollen of Zea (corn) appears at Lake Patzcuaro along with low peaks of chenopod and grass pollen at 3500 yr B.P. apparently recording a human population large enough to modify the natural environment, as well as the beginning of agriculture. A rich aquatic flora in this phase suggests eutrophication of the lake by slope erosion. In the most recent period corn is absent from the sediments, perhaps reflecting a change in agricultural practices. The environment changes at Lake Patzcuaro are similar to and correlate with those in the Cuenca de Mexico, where diatom stratigraphy from the Chalco basin indicates fluctuations in lake levels and lake chemistry in response to variations in available moisture. Before 10,000 yr ago climates there were cool and dry, and the Chalco basin was occupied by a shallow freshwater marsh that drained north to Lake Texcoco, where saline water accumulated by evaporation. Increases in effective moisture and possible melting of glaciers during the Holocene caused lake levels to rise throughout the Cuenca de Mexico, and Lake Texcoco flooded the Chalco basin with

  14. Shallow geothermal investigations into the existence of the Valles Caldera outflow plume near Ponderosa and Jemez Pueblo, north-central, New Mexico

    Science.gov (United States)

    Salaz, Robert Ezekiel

    Geothermal research within the Jemez Mountains spans several decades and is documented in many papers. This study serves to extend the research boundary to the south and east outside of Valles caldera and Canon de San Diego, where the main occurrences of geothermal activity are located. The focus of this investigation is to test for a deep ~900 m, stratigraphically-bound thermal aquifer within the Madera Limestone along the western margin of the Santo Domingo basin transition zone near Ponderosa and Jemez Pueblo, in north-central New Mexico. Numerous springs were sampled for aqueous geochemistry to identify leakage of a deeper geothermal aquifer into shallow aquifers. Wells were sampled for temperature anomalies. In addition, two travertine deposits were analyzed for stable isotope composition and one deposit was dated using U-Series techniques to assess the timing and origin of deposition. This study is important because researchers in other extensional basins have identified reasonably good geothermal reservoirs in deep carbonate aquifers that are similar in geologic setting to the Madera Limestone aquifer of this study. The existence of a deep geothermal aquifer near Ponderosa and Jemez Pueblo, New Mexico could prove to be another prospect for geothermal exploration in the Jemez Mountains. Aqueous geochemistry of springs are plotted on ternary Piper diagrams to help classify similar geochemical trends and group these trends into recognizable patterns. These data indicate calcium carbonate rich waters in the north that may gradationally change to alkaline type waters as they flow south through the study area. Contrasting this data, SiO2 and TDS concentrations show two separate systems that may indicate separate confined aquifers. Two distinct TDS regions are observed, one with higher concentrations (>1000 ppm) shows a decrease from N-S and one with lower concentrations (ProQuest.).

  15. Distribution and abundance of cetaceans in the north-central and western Gulf of Mexico. Final report. Volume 3. Appendix A

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.W.; Fargion, G.S.

    1996-05-24

    The purpose of the study was to determine the distribution and abundance of cetaceans in areas potentially affected by future oil and gas activities along the continental slope of the north-central and western Gulf of Mexico. This 3.75 year project commenced 1 October 1991 and finished 15 July 1995. The study area was bounded by the Florida-Alabama border, the Texas-Mexico border, and the 100 m and 2,000 m isobaths. Cetacean distribution and abundance were determined from seasonal aerial and shipboard visual surveys and shipboard acoustic surveys. In addition, hydrographic data were collected in situ and by satellite remote sensing to characterize cetacean habitat. Finally, tagging and tracking of sperm whales using satellite telemetry was attempted. Appendix A contains: the cetacean, trutle, and bird sighting data from all shipboard and aerial visual surveys; contact data from the shipboard acoustic survey; and the cetacean environmental profiles. Cetaceans were observed throughout the study area during all four seasons. Nineteen species were identified, including two species (melon-headed whales and Fraser`s dolphins) previously thought to be rare in the Gulf. Pantropical spotted dolphins, bottlenose dolphins, clymene dolphins, striped dolphins, Atlantic spotted dolphins, and melon-headed whales were the most common small cetaceans and the sperm whale was the most common large cetacean. The mean annual abundance for all cetaceans was estimated to be 19,198. Although the study area had complex and dynamic oceanography, bottom depth was the only environmental variable which correlated to cetacean distribution.

  16. Integrative taxonomy identifies a new species of Phyllodistomum (Digenea: Gorgoderidae) from the twospot livebearer, Heterandria bimaculata (Teleostei: Poeciliidae), in Central Veracruz, Mexico.

    Science.gov (United States)

    Razo-Mendivil, Ulises; Pérez-Ponce de León, Gerardo; Rubio-Godoy, Miguel

    2013-12-01

    Phyllodistomum inecoli n. sp. is described from the twospot livebearer, Heterandria bimaculata (Teleostei: Poeciliidae), collected in the Río La Antigua basin, Veracruz, Mexico. The new species is described and characterised by using a combination of morphology, scanning electron microscopy, and sequences of nuclear and mitochondrial genes. Diagnostic characters of the new species of Phyllodistomum include a genital pore opening at the level of the caecal bifurcation; oval vitellarium, situated just posterior to the ventral sucker and not extended laterally and anterior extracaecal uterine loops variable in extension (reaching the anterior, median or posterior margin of the ventral sucker). P. inecoli n. sp. most closely resembles P. brevicecum, a species described as a parasite of the central mudminnow, Umbra limi, in other parts of North America; however, the genital pore in P. brevicecum is situated between the caecal bifurcation and the ventral sucker, the ovary is larger, the vitellarium is lobed and extended laterally and the anterior portion of the uterus extends to the posterior margin of the ventral sucker. Comparison of about 1,500–2,200 nucleotides of cox1 and 28S rDNA and ITS1 strongly supports the status of P. inecoli as a new species. Bayesian inference analysis of combined datasets of 28S rDNA and cox1 sequences showed that P. inecoli n. sp. and the other species found in freshwater fishes of Mexico, including the species complex of P. lacustri, are not sister species. Phylogenetic analysis based on 28S rDNA sequences of several gorgoderid taxa revealed the close relationship of P. inecoli n. sp. with several species of Phyllodistomum, Gorgodera and Gorgoderina with cystocercous cercariae developing in sphaeriid bivalves. Dot-plot analysis of ITS1 sequences of P. inecoli n. sp. revealed the presence of eight repetitive elements with different length, which together represent almost half the length of ITS1.

  17. Mexico Terrain Corrected Free Air Anomalies (97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' gravity anomaly grid for Mexico, North-Central America and the Western Caribbean Sea is NOT the input data set used in the development of the MEXICO97 model....

  18. Occurrence of entomopathogenic fungi and parasitic nematodes on Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae collected in Central Chiapas, Mexico

    Science.gov (United States)

    Fall armyworm larvae (FAW), Spodoptera frugiperda (J. E. Smith) were collected from whorl-stage cornfields, between the V2 and V4 stages, in 22 localities of Central, Chiapas, México, called "La Frailesca" during late June 2009 to determine the occurrence of native entomopathogens and parasitic nema...

  19. 76 FR 14040 - Outer Continental Shelf (OCS), Central and Western Gulf of Mexico, Oil and Gas Lease Sales for...

    Science.gov (United States)

    2011-03-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf (OCS), Central and... Environmental Policy Act (NEPA), the Outer Continental Shelf Lands Act (OCSLA), and the Coastal Zone...

  20. Hydrothermal Evolution of the Giant Cenozoic Kadjaran porphyry Cu-Mo deposit, Tethyan metallogenic belt, Armenia, Lesser Caucasus: mineral paragenetic, cathodoluminescence and fluid inclusion constraints

    Science.gov (United States)

    Hovakimyan, Samvel; Moritz, Robert; Tayan, Rodrik; Rezeau, Hervé

    2016-04-01

    The Lesser Caucasus belongs to the Central segment of the Tethyan metallogenic belt and it is a key area to understand the metallogenic evolution between the Western & Central parts of the Tethyan belt and its extension into Iran. Zangezur is the most important mineral district in the southernmost Lesser Caucasus. It is a component of the South Armenian block, and it was generated during the convergence and collision of the southern margin of the Eurasian plate and the northern margin of the Arabian plate, and terranes of Gondwana origin (Moritz et al., in press). The Zangezur ore district consists of the Tertiary Meghri-Ordubad composite pluton, which is characterized by a long-lasting Eocene to Pliocene magmatic, tectonic and metallogenic evolution. It hosts major porphyries Cu-Mo and epithermal Au - polymetallic deposits and occurrences, including the giant world class Kadjaran porphyry Cu-Mo deposit (2244 Mt reserves, 0.3% Cu, 0.05% Mo and 0.02 g/t Au). The Kadjaran deposit is hosted by a monzonite intrusion (31.83±0.02Ma; Moritz et al., in press). Detailed field studies of the porphyry stockwork and veins of the different mineralization stages, their crosscutting and displacement relationships and the age relationship between different paragenetic mineral associations were the criteria for distinction of the main stages of porphyry mineralization at the Kadjaran deposit. The economic stages being: quartz- molybdenite, quartz-molybdenite-chalcopyrite, and quartz-chalcopyrite. The main paragenetic association of the Kadjaran porphyry deposit includes pyrite, molybdenite, chalcopyrite, bornite, chalcocite, pyrrhotite, covellite, sphalerite, and galena. Recent field observations in the Kadjaran open pit revealed the presence of epithermal veins with late vuggy silica and advanced argillic alteration in the north-eastern and eastern parts of the deposit. They are distributed as separate veins and have also been recognized in re-opened porphyry veins and in

  1. The origin of groundwater arsenic and fluorine in a volcanic sedimentary basin in central Mexico: a hydrochemistry hypothesis

    Science.gov (United States)

    Morales-Arredondo, Iván; Rodríguez, Ramiro; Armienta, Maria Aurora; Villanueva-Estrada, Ruth Esther

    2016-06-01

    A groundwater sampling campaign was carried out in the summer of 2013 in a low-temperature geothermal system located in Juventino Rosas (JR) municipality, Guanajuato State, Mexico. This groundwater presents high concentrations of As and F- and high Rn counts, mainly in wells with relatively higher temperature. The chemistry of major elements was interpreted with different methods, like Piper and D'Amore diagrams. These diagrams allowed for classification of four groundwater types located in three hydrogeological environments. The aquifers are hosted mainly in alluvial-lacustrine sediments and volcanic rocks in interaction with fault and fracture systems. The subsidence, faults and fractures observed in the study area can act as preferential channels for recharge and also for the transport of deep fluids to the surface, especially in the basin plain. The formation of a piezometric dome and the observed hydrochemical behavior of groundwater suggest a possible origin of the As and F-. Geochemical processes occurring during water-rock interaction are related to high concentrations of As and F-. High temperatures and alteration processes (like rock weathering) induce dissolution of As and F--bearing minerals, increasing the content of these elements in groundwater.

  2. Repeated volcanic disasters in Prehispanic time at Popocatépetl, central Mexico: Past key to the future?

    Science.gov (United States)

    Siebe, Claus; Abrams, Michael; Macías, José Luis; Obenholzner, Johannes

    1996-05-01

    The Holocene eruptive history of Popocatépetl volcano is characterized by recurrent voluminous Plinian eruptions every 1000 to 3000 yr, the most recent of which destroyed human settlements. Major eruptions occurred between 3195 and 2830 B.C., 800 and 215 B.C., and A.D. 675 and 1095. The three eruptions followed a similar pattern and started with minor ash fall and ash flows. The eruptions reached their peak with a main Plinian pulse that produced deposition of a pumice fall, the emplacement of hot ash flows, and finally extensive mudflows. Each time the area of devastation had become repopulated, before being devastated once again. During the last eruption several settlements, including Cholula (a major urban center), were inundated by lahars. A scenario of the possible recurrence of an eruption of similar magnitude, which would have disastrous consequences for the now highly populated areas around Popocatépetl, should be considered seriously in any volcano emergency contingency plan. This is especially important because more than one million people are living within a radius of 35 km around the volcano (the outskirts of Mexico City are at a distance of 40 km), and Popocatépetl resumed emitting ash on December 21, 1994, after decades of dormancy.

  3. Magmatic Conduit Metallogenic System - A New Model for the Origin of Ore-deposits

    Science.gov (United States)

    Su, S.; Tang, Z.; Wu, G.; Deng, J.; Xiao, Q.; Luo, Z.; Cui, Y.

    2013-12-01

    Origin and emplacement processes of ore-deposits connected with intrusions remains poorly understood. Here we propose a new model 'Magmatic Conduit Metallogenic System' to explain the origin of ore-deposits. Magmatic flow (or Melt-fluid flow) bearing metals will finally settle in the conduits at later stage of magma evolved in magma metallogenic system. Magmatic flow (or Melt-fluid flow) bearing metals include many types, such as sulfide melts and iron melts bearing fluids. Conduits will form along the zones of structural weakness, such as fault zone and interface of two different types of rocks. These conduits are usually very complicated in the magmatic system, exemplified by two typical ore-deposits, detailed as follows. The Jinchuan sulfide deposit, located in Gansu Province, China, is the third largest magmatic Cu-Ni Platinum Group Elements (PGE) in the world. There are mainly four orebodies (orebody 58, 24, 1, and 2) from west to east, with Ni/Cu value at 1.24, 1.56, 1.83 and 2.06 respectively; the content of Pt+Pd ranges from 0.4 to 10.3 ppm, with the highest value occurs in the west. This suggests that the direction of the melt flow bearing sulfide is from west to east and the front of the conduit system is in the east part of the deposit. Sulfide segregation in the magmatic chamber or in the conduits might have caused ore content to change in different part of the conduit systems. Another typical example is the Xishimen iron deposit, which is located in the South of Hebei Province, China. It has been considered as a skarn-type iron deposit conventionally. However, many geological evidence suggests that Xishimen iron deposit is a magmatic iron deposit instead. Such evidence includes: 1. The boundaries between iron orebodies and country rocks are obvious, no transitional relationship; 2. Iron ore body injected into the country rocks (including genesis, diorite, and marble); 3. There are some vesicular in the iron ores; 4. Magnetite as an interstitial mineral

  4. Magmatism and polymetallic mineralization in southwestern Qinzhou-Hangzhou metallogenic belt, South China

    Science.gov (United States)

    Huang, Xudong; Lu, Jianjun; Wang, Rucheng; Ma, Dongsheng

    2016-04-01

    As Neoproterozoic suture zone between the Yangtze Block and Cathaysia Block, Qinzhou-Hangzhou metallogenic belt is one of the 21 key metallogenic belts in China. Intensive multiple-aged felsic magmatism and related polymetallic mineralization take place in this belt. Although Neoproterozoic, Paleozoic, Triassic granites and associated deposits have been found in southwestern Qinzhou-Hangzhou metallogenic belt, Middle-Late Jurassic (150-165 Ma) magmatism and related mineralization is of the most importance. Three major kinds of Middle-Late Jurassic granitoids have been distinguished. (Cu)-Pb-Zn-bearing granitoids are slightly differentiated, calc-alkaline and metaluminous dioritic to granodioritic rocks. Sn-(W)-bearing granites contain dark microgranular enclaves and have high contents of REE and HFSE, suggesting affinities of aluminous A-type (A2) granites. W-bearing granites are highly differentiated and peraluminous rocks. (Cu)-Pb-Zn-bearing granitoids have ɛNd(t) values of -11 ˜ -4 and ɛHf(t) values of -12 ˜ -7, corresponding to TDMC(Nd) from 1.4 to 1.8 Ga and TDMC(Hf) from 1.6 to 2.0 Ga, respectively. The ɛNd(t) values of W-bearing granites vary from -11 to -8 with TDMC(Nd) of 1.6 ˜ 1.9 Ga and ɛHf(t) values change from -16 to -7 with TDMC(Hf) of 1.5 ˜ 2.0 Ga. Compared with (Cu)-Pb-Zn-bearing granitoids and W-bearing granites, the Sn-(W)-bearing granites have higher ɛNd(t) (-8 ˜ -2) and ɛHf(t) (-8 ˜ -2) values and younger TDMC(Nd) (1.1 ˜ 1.6 Ga) and TDMC(Hf) (1.2 ˜ 1.8 Ga) values, showing a more juvenile isotopic character. Sn-(W)-bearing granites originate from partial melting of granulitized lower crust involved with some mantle-derived materials. W-bearing granites are derived from partial melting of crust. (Cu)-Pb-Zn-bearing granitoids are also derived from crust but may be influenced by more mantle-derived materials. For (Cu)-Pb-Zn deposits, skarn and carbonate replacement are the most important mineralization types. Cu ore bodies mainly

  5. Confirmation and Significance of Caledonian Metallogenic Epoch for Gold Deposits in South China

    Institute of Scientific and Technical Information of China (English)

    王秀璋; 梁华英; 单强; 程景平; 夏萍

    2001-01-01

    Caledonian gold deposits are widely distributed in South China. They are developed in both South China Caledonian fold belt and adjacent Proterozoic Jiangnan uplift. The host rocks are Proterozoic metamorphosed microclastic rocks in the Jiangnan uplift and Proterozoic and Cambrian strata, as well as Chengjiang and Caledonian igneous bodies in the South China fold belt. The distinct differences between the Caledonian and the most developed Yenshanian gold deposits in South China are reflected in age and host-rock type, relations to Yenshanian magmatic activities, element association, mineral assemblage and gold deposit type. The stud ies have proven that the Caledonian epoch is a principal metallogenic period of gold deposits in South China. This conclusion is of very important enlightening significance in exploration of Caledonian gold deposits in South China as well as in other Caledonian fold belts and adjacent u plifts in China.

  6. Nitrous oxide flux in maize and wheat cropped soils in the central region of Mexico during El nino year 1998

    Energy Technology Data Exchange (ETDEWEB)

    Longoria Ramirez, R. [Centro Nacional de Investigaciones y Desarrollo Tecnologico, Mexico, D.F. (Mexico); Carbajal Benitez, G.; Mar Morales, B.E.; Ruiz Suarez, G. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, (UNAM), Mexico, D.F. (Mexico)

    2003-10-01

    Emissions of nitrous oxide (N{sub 2}O) were measured in agricultural lands used for farming wheat and maize during 1998 in the states of Hidalgo and Tlaxcala in Mexico. In an irrigated wheat field (El Tenhe, Hidalgo), an average flux of -10.85 {mu}g N{sub 2}O - N m{sup -}2 h{sup -}1 was obtained for the total cycle (155 days between December and May). There, high negative values were observed with Water Fill Porous Space (WFPS) close to 70%. The average flux of the complete cycle (269 days between March and December) in an irrigated maize field (El Progreso, Hidalgo) was 37.43 {mu}g N{sub 2}O - N m{sup -}2 h{sup -}1. In this case, more insignificant negative fluxes were found with WFPS close to 45% or less. These last results may have been influenced by the strong El Nino, which occurred in the middle of 1998. Twenty once percent of the measurements in the state of Hidalgo showed soil acting as a nitrous oxide sink. The samples from Tlaxcala showed that these fields acted as emitters. In the rain fed fields in the state of Tlaxcala, an average flux of 121 {mu}g N{sub 2}O - N m{sup -}2 h{sup -}1 was obtained for the wheat field. The farming season lasted 142 days, from July to December. In addition, for the maize field the averaged flux was 285.61 {mu}g N{sub 2}O - Nm{sup -}2h-1. The farming season lasted 246 days, from April to December. [Spanish] En 1998 se midieron las emisiones de oxido nitroso (N{sub 2}O) de suelos agricolas para cultivar trigo y maiz en los estados de Hidalgo y Tlaxcala, en Mexico. Para un campo irrigado de trigo (El Tenhe, Hidalgo), se obtuvo un flujo promedio de -10.85 {mu}g N{sub 2}O - N m{sup -}2 h{sup -}1 para el ciclo total (155 dias entre diciembre y mayo). En este caso se observaron valores negativos elevados en el espacio poroso relleno de agua (VFPS, pos sus siglas en ingles), cercanos a 70%. El flujo promedio para el ciclo completo (269 dias entre marzo y diciembre) en un campo irrigado de maiz fue de 37.43 {mu}g N{sub 2}O - N m

  7. Mountain cloud forest and grown-shade coffee plantations: A comparison of tree biodiversity in central Veracruz, Mexico

    Directory of Open Access Journals (Sweden)

    Alfredo González-Zamora

    2016-04-01

    Full Text Available Aim of the study: The objective of this work is to compare tree diversity and richness among one grown-shade coffee plantation (CAE and two sites of montane cloud forests, one preserved (MCF1 and other perturbed (MCF2. We also develop an analysis of the importance of coffee plantations as a refuge of tree species, holding a potential role for conservation.Area of study: Our study area is the coffee region of Coatepec-Xico, in the state of Veracruz, Mexico.Material and methods: We compiled a list of all tree species in each site to determine tree diversity and floristic similarity (dissimilarity. We used different similarity indices and a cluster analysis to show relations among sites.Main results: 2721 individuals from 154 species were registered in the montane cloud forests as a whole. In the grown-shade coffee plantation we registered 2947 individuals from 64 species. The most similar sites were the perturbed montane cloud forest and the grown-shade coffee plantation and the least similar were the preserved montane cloud forest and the grown-shade coffee plantation. The high biodiversity found in all sites and the differences in tree composition between the two montane cloud forests supports evidence of the ecosystems richness in the region.Research highlight: Diversity differences among sites determine that the grown-shade coffee plantation is not substitute for montane cloud forest. CAE’s are developed under similar environmental conditions than the MCF; therefore, coexistence and recombination (replacement of species make them particularly complementary. CAE’s in Veracruz have a potential role as refuge for biodiversity.

  8. Assessment of selected inorganic constituents in streams in the Central Arizona Basins Study Area, Arizona and northern Mexico, through 1998

    Science.gov (United States)

    Anning, David W.

    2003-01-01

    Stream properties and water-chemistry constituent concentrations from data collected by the National Water-Quality Assessment and other U.S. Geological Survey water-quality programs were analyzed to (1) assess water quality, (2) determine natural and human factors affecting water quality, and (3) compute stream loads for the surface-water resources in the Central Arizona Basins study area. Stream temperature, pH, dissolved-oxygen concentration and percent saturation, and dissolved-solids, suspended-sediment, and nutrient concentration data collected at 41 stream-water quality monitoring stations through water year 1998 were used in this assessment. Water-quality standards applicable to the stream properties and water-chemistry constituent concentration data for the stations investigated in this study generally were met, although there were some exceedences. In a few samples from the White River, the Black River, and the Salt River below Stewart Mountain Dam, the pH in reaches designated as a domestic drinking water source was higher than the State of Arizona standard. More than half of the samples from the Salt River below Stewart Mountain Dam and almost all of the samples from the stations on the Central Arizona Project Canal?two of the three most important surface-water sources used for drinking water in the Central Arizona Basins study area?exceeded the U.S. Environmental Protection Agency drinking water Secondary Maximum Contaminant Level for dissolved solids. Two reach-specific standards for nutrients established by the State of Arizona were exceeded many times: (1) the annual mean concentration of total phosphorus was exceeded during several years at stations on the main stems of the Salt and Verde Rivers, and (2) the annual mean concentration of total nitrogen was exceeded during several years at the Salt River near Roosevelt and at the Salt River below Stewart Mountain Dam. Stream properties and water-chemistry constituent concentrations were related to

  9. Accumulation of pharmaceuticals, Enterococcus, and resistance genes in soils irrigated with wastewater for zero to 100 years in central Mexico.

    Directory of Open Access Journals (Sweden)

    Philipp Dalkmann

    Full Text Available Irrigation with wastewater releases pharmaceuticals, pathogenic bacteria, and resistance genes, but little is known about the accumulation of these contaminants in the environment when wastewater is applied for decades. We sampled a chronosequence of soils that were variously irrigated with wastewater from zero up to 100 years in the Mezquital Valley, Mexico, and investigated the accumulation of ciprofloxacin, enrofloxacin, sulfamethoxazole, trimethoprim, clarithromycin, carbamazepine, bezafibrate, naproxen, diclofenac, as well as the occurrence of Enterococcus spp., and sul and qnr resistance genes. Total concentrations of ciprofloxacin, sulfamethoxazole, and carbamazepine increased with irrigation duration reaching 95% of their upper limit of 1.4 µg/kg (ciprofloxacin, 4.3 µg/kg (sulfamethoxazole, and 5.4 µg/kg (carbamazepine in soils irrigated for 19-28 years. Accumulation was soil-type-specific, with largest accumulation rates in Leptosols and no time-trend in Vertisols. Acidic pharmaceuticals (diclofenac, naproxen, bezafibrate were not retained and thus did not accumulate in soils. We did not detect qnrA genes, but qnrS and qnrB genes were found in two of the irrigated soils. Relative concentrations of sul1 genes in irrigated soils were two orders of magnitude larger (3.15 × 10(-3 ± 0.22 × 10(-3 copies/16S rDNA than in non-irrigated soils (4.35 × 10(-5± 1.00 × 10(-5 copies/16S rDNA, while those of sul2 exceeded the ones in non-irrigated soils still by a factor of 22 (6.61 × 10(-4 ± 0.59 × 10(-4 versus 2.99 × 10(-5 ± 0.26 × 10(-5 copies/16S rDNA. Absolute numbers of sul genes continued to increase with prolonging irrigation together with Enterococcus spp. 23S rDNA and total 16S rDNA contents. Increasing total concentrations of antibiotics in soil are not accompanied by increasing relative abundances of resistance genes. Nevertheless, wastewater irrigation enlarges the absolute concentration of resistance genes in soils due to a

  10. Public Participation as an Aid to Conserve Little Known Species: The Case of the Neotropical Otter Lontra Longicaudis (Olfers, 1818 in Central Mexico

    Directory of Open Access Journals (Sweden)

    Eric Ramírez-Bravo

    2013-01-01

    Full Text Available Public participation is often disregarded during conservation projects despite the potential benefits as it can help to determine priority areas for conservation in highly fragmented landscapes or to increase knowledge of little known species. However, there is no information about its potential application in Central Mexico. We undertook a preliminary assessment based on 30 interviews preformed between December 2011 and May 2012 with hunters aimed to determine the presence, feeding habits, reproduction periods, and –threats of the neotropical otter (Lontra longicaudis in a fragmented landscape in the Sierra Madre Oriental. Twenty three of the interviewed hunters indicated that the species is rare and considered to be solitary however, they have observed cubs and pregnant females feeding mainly on fish and crustaceans were made. Pollution, shortage of prey, habitat disturbance, and hunting were the main threats on the species. We verified the presence responses of the neotropical otter through field work and the life history information was obtained by doing a literature review. We concluded that public participation can be confidently incorporated in conservation plans of the neotropical otter in the Sierra Madre Oriental.

  11. Resource Assessment of the In-Place and Potentially Recoverable Deep Natural Gas Resource of the Onshore Interior Salt Basins, North Central and Northeastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby

    2005-10-28

    The principal research effort for Year 2 of the project has been petroleum system characterization and modeling. Understanding the burial, thermal maturation, and hydrocarbon expulsion histories of the strata in the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas is important in hydrocarbon resource assessment. The underburden and overburden rocks in these basins and subbasins are a product of their rift-related geohistory. Petroleum source rock analysis and initial thermal maturation and hydrocarbon expulsion modeling indicated that an effective regional petroleum source rock in the onshore interior salt basins and subbasins, the North Louisiana Salt Basin, Mississippi Interior Salt Basin, Manila Subbasin and Conecuh Subbasin, was Upper Jurassic Smackover lime mudstone. The initial modeling also indicated that hydrocarbon generation and expulsion were initiated in the Early Cretaceous and continued into the Tertiary in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin and that hydrocarbon generation and expulsion were initiated in the Late Cretaceous and continued into the Tertiary in the Manila Subbasin and Conecuh Subbasin. Refined thermal maturation and hydrocarbon expulsion modeling and additional petroleum source rock analysis have confirmed that the major source rock in the onshore interior salt basins and subbasins is Upper Jurassic Smackover lime mudstone. Hydrocarbon generation and expulsion were initiated in the Early to Late Cretaceous and continued into the Tertiary.

  12. Gastrointestinal nematode burden in working equids from humid tropical areas of central Veracruz, Mexico, and its relationship with body condition and haematological values.

    Science.gov (United States)

    Valdéz-Cruz, Maura Pilar; Hernández-Gil, Mariano; Galindo-Rodríguez, Leticia; Alonso-Díaz, Miguel Angel

    2013-02-01

    The east coast of Veracruz, Mexico, has an important equine population used for working in rural production systems. The objectives of this study were (1) to calculate the prevalence of tropical working equids (donkeys, mules and horses) infected with gastrointestinal nematodes (GINs) and the GINs involved, and (2) to measure the body condition score (BCS) and haematological values for each working equid and its relationship with faecal worm egg count (EPG). One hundred and forty working equids were randomly selected from five different villages along the central coast of the state of Veracruz and faecal and blood samples were obtained from each animal. Gastrointestinal parasite burdens were determined using the McMaster technique. Packed cell volume, total plasma proteins, red blood cell count and white blood cell count were measured from each blood sample. Prevalence of infected equids was higher than 90 %. Mules had the highest median faecal worm egg counts (875 EPG), followed by horses and donkeys with 400 EPG. There was no correlation between EPG and BCS or haematological values (p > 0.05). Results suggest that despite the high prevalence and parasite burdens, equids involved in this trial are not being seriously affected. This study provides information which might help in designing future strategies to control nematode infections in working equids in the Mexican tropics; more emphasis should be placed on other inputs (nutrition perhaps), with individual anthelminthic treatment to those animals with the highest EPG or when signs present themselves.

  13. Analysis of diatomite sediments from a paleolake in central Mexico using PIXE, X-ray tomography and X-ray diffraction

    Science.gov (United States)

    Miranda, J.; Oliver, A.; Vilaclara, G.; Rico-Montiel, R.; Macías, V. M.; Ruvalcaba, J. L.; Zenteno, M. A.

    1994-03-01

    Diatomite samples from paleolake Tlaxcala, in Central Mexico, have been analyzed using proton induced X-ray emission (PIXE), X-ray tomography and X-ray diffraction. Chiseled blocks were scanned with a 0.7 MeV proton beam, 0.1 mm in diameter, in 0.25 mm steps across the sediments. X-ray tomography with the same step sizes was then applied, in order to compare the concentrations obtained with PIXE and the material density in the sediment layers. Three different kinds of layers were found, related to their colors: dark, white and gray. The composition of the layers is fairly uniform. The dark zone is enriched in Al, K, Ca, Ti, Mn, and Fe. This dark layer may be associated with eruptions of the Malitzin volcano. The white zone is found to contain diatomite of a high purity, with traces of K, Ca, and Fe, while the gray zones are also Al enriched, suggesting a clay contamination of the diatomite. X-ray diffraction of materials obtained from each main layer showed that the white and gray phases are highly amorphous, with a small component of cristobalite, as expected from the diatom sediment diagenesis, while the dark layer contains also important amounts of anorthite and orthoclase, supporting the volcanic origin of this layer.

  14. Two new species of Urocleidoides Mizelle et Price, 1964 (Monogenoidea) from the gill lamellae of profundulids and poeciliids from Central America and southern Mexico.

    Science.gov (United States)

    Mendoza-Franco, Edgar F; Caspeta-Mandujano, Juan Manuel; Salgado-Maldonado, Guillermo; Matamoros, Wilfredo Antonio

    2015-09-07

    During investigations of gill ectoparasites (Platyhelminthes) parasitising freshwater fish from Central America (Guatemala, Honduras, El Salvador and Panama) and southeastern Mexico (Guerrero, Oaxaca and Chiapas), the following dactylogyrid monogenoidean were found: Urocleidoides simonae sp. n. from Profundulus punctatus (Günther) (type host), Profundulus balsanus Ahl, Profundulus guatemalensis (Günther), Profundulus kreiseri Matamoros, Shaefer, Hernández et Chakrabarty, Profundulus labialis (Günther), Profundulus oaxacae (Meek), Profundulus sp. 1 and Profundulus sp. 2 (all Profundulidae); Urocleidoides vaginoclaustroides sp. n. from Pseudoxiphophorus bimaculata (Heckel) (type host) and Poeciliopsis retropinna (Regan) (both Poeciliidae); and Urocleidoides vaginoclaustrum Jogunoori, Kritsky et Venkatanarasaiah, 2004 from P. labialis, Profundulus portillorum Matamoros et Shaefer and Xiphophorus hellerii Heckel (Poeciliidae). Urocleidoides simonae sp. n. differs from all other congeneric species in having anchors with well-differentiated roots, curved elongate shaft and short point. Urocleidoides vaginoclaustroides sp. n. most closely resembles U. vaginoclaustrum, but differs from this species mainly in the shape of its anchors (i.e. evenly curved shaft and short point vs curved shaft and elongate point extending just past the tip of the superficial anchor root). The complexity of potential hosts for species of Urocleidoides and their effect on its distribution on profundulid and poeciliid fishes are briefly discussed.

  15. Quantity and location of groundwater recharge in the Sacramento Mountains, south-central New Mexico (USA), and their relation to the adjacent Roswell Artesian Basin

    Science.gov (United States)

    Rawling, Geoffrey C.; Newton, B. Talon

    2016-06-01

    The Sacramento Mountains and the adjacent Roswell Artesian Basin, in south-central New Mexico (USA), comprise a regional hydrologic system, wherein recharge in the mountains ultimately supplies water to the confined basin aquifer. Geologic, hydrologic, geochemical, and climatologic data were used to delineate the area of recharge in the southern Sacramento Mountains. The water-table fluctuation and chloride mass-balance methods were used to quantify recharge over a range of spatial and temporal scales. Extrapolation of the quantitative recharge estimates to the entire Sacramento Mountains region allowed comparison with previous recharge estimates for the northern Sacramento Mountains and the Roswell Artesian Basin. Recharge in the Sacramento Mountains is estimated to range from 159.86 × 106 to 209.42 × 106 m3/year. Both the location of recharge and range in estimates is consistent with previous work that suggests that ~75 % of the recharge to the confined aquifer in the Roswell Artesian Basin has moved downgradient through the Yeso Formation from distal recharge areas in the Sacramento Mountains. A smaller recharge component is derived from infiltration of streamflow beneath the major drainages that cross the Pecos Slope, but in the southern Sacramento Mountains much of this water is ultimately derived from spring discharge. Direct recharge across the Pecos Slope between the mountains and the confined basin aquifer is much smaller than either of the other two components.

  16. Intercropped oats (Avena sativa) - common vetch (Vicia sativa) silage in the dry season for small-scale dairy systems in the highlands of central Mexico.

    Science.gov (United States)

    Garduño-Castro, Y; Espinoza-Ortega, A; González-Esquivel, C E; Mateo-Salazar, B; Arriaga-Jordán, C M

    2009-06-01

    Small-scale dairy systems in the highlands of central Mexico require feeding strategies based on quality home-grown forage that may reduce high concentrate costs. Eight Holstein cows paired by parity and date of calving were used in a split-plot experiment to evaluate supplementing 6 kg DM/cow/d of oat-vetch silage (OVS) in comparison to maize silage (MS) as dry season feeding, for a more intensive use of the land through an oat-vetch catch crop. Cows had 9 h/d access to continuous grazing of perennial ryegrass - white clover pasture and 4 kg/d of commercial concentrate. The 9 week experiment, recorded weekly milk yield and composition, and body condition score and live-weight every fortnight. Milk yield was 20.1 kg/cow/d for OVS and 15.4 for MS (SEM +/-2.9, P > 0.05), with no differences for fat or protein content, body condition score, or live-weight (P > 0.05). The economic analysis showed that although feeding costs were higher for OVS, margins were greater than for MS, with feeding cost per litre of $0.21 for MS and $0.16 for OVS. OVS is a viable catch crop after the MS harvest that can substitute MS in the dry season enabling a more intensive use of the land.

  17. Uranium hydrogeochemical survey of well waters from an area around Pie Town, Catron County, West-Central New Mexico, including concentrations of twenty-three additional elements

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, T.L.; George, W.E.; Hensley, W.K.; Thomas, G.J.; Langhorst, A.L.

    1980-10-01

    As part of the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the National Uranium Resource Evaluation (NURE) sponsored by the US Department of Energy (DOE), the Los Alamos Scientific Laboratory (LASL) conducted a detailed hydrogeochemical survey of well waters in a 4250-km/sup 2/ area near Pie Town in west-central New Mexico. A total of 300 well samples was collected and analyzed for uranium and 23 other elements. The results of these analyses and carbonate and bicarbonate ion concentrations are presented in the Appendixes of this report. Uranium concentrations range from below the detection limit of 0.02 parts per billion (ppB) to 293.18 ppB and average 8.71 ppB. Samples containing high levels of uranium were collected from the Largo Creek valley west of Quemado, from a small area about 6 km east of Quemado, from a small area surrounding Pie Town, and from scattered locations in the area surrounding Adams Diggings north of Pie Town. Most of the samples containing high uranium concentrations were collected from wells associated with the volcanic sedimentary facies of the Datil formation. This formation is a likely source of mobile uranium that may be precipitating in the underlying Baca formation, a known uranium host unit. Bicarbonate ion concentration, while proportional to uranium concentration in some cases, is not a strong controlling factor in the uranium concentrations in samples from this area.

  18. Medical therapeutic itineraries of women with breast cancer diagnosis affiliated to the People's Health Insurance in San Luis Potosí, central Mexico.

    Science.gov (United States)

    Tejada-Tayabas, Luz María; Salcedo, Liseth Amell; Espino, Joel Monárrez

    2015-01-01

    This study aims to describe the medical itineraries followed by breast cancer women affiliated to the People's Health Insurance in San Luis Potosí, central Mexico. We used an ethnographic approach based on oral histories of 12 women diagnosed with breast cancer in the year prior to the first meeting. Two face-to-face sessions per participant lasting 60 minutes each were conducted followed by a telephone interview. Content and diachronic analyses were used. Three main itineraries were identified: (1) diagnostic process, (2) final diagnosis to treatment, and (3) cancer control and relapse. Findings suggested that infrastructure and human resources to adequately screen and timely diagnose breast cancer were scant and insufficiently trained, respectively. Deferral of medical assessment was related with lack of information about breast cancer consequences, with women being afraid of a positive result, and with economic constraints. The current screening program needs to be redesigned to prevent diagnostic delays, as these seem to explain the high frequency of advanced stages reported at the time of diagnosis.

  19. Medical therapeutic itineraries of women with breast cancer diagnosis affiliated to the People's Health Insurance in San Luis Potosí, central Mexico

    Directory of Open Access Journals (Sweden)

    Luz María Tejada-Tayabas

    2015-01-01

    Full Text Available This study aims to describe the medical itineraries followed by breast cancer women affiliated to the People's Health Insurance in San Luis Potosí, central Mexico. We used an ethnographic approach based on oral histories of 12 women diagnosed with breast cancer in the year prior to the first meeting. Two face-to-face sessions per participant lasting 60 minutes each were conducted followed by a telephone interview. Content and diachronic analyses were used. Three main itineraries were identified: (1 diagnostic process, (2 final diagnosis to treatment, and (3 cancer control and relapse. Findings suggested that infrastructure and human resources to adequately screen and timely diagnose breast cancer were scant and insufficiently trained, respectively. Deferral of medical assessment was related with lack of information about breast cancer consequences, with women being afraid of a positive result, and with economic constraints. The current screening program needs to be redesigned to prevent diagnostic delays, as these seem to explain the high frequency of advanced stages reported at the time of diagnosis.

  20. A Study on the Knowledge, Perception, and Use of Breast Cancer Screening Methods and Quality of Care Among Women from Central Mexico.

    Science.gov (United States)

    Cruz-Castillo, Andrea B; Hernández-Valero, María A; Hovick, Shelly R; Campuzano-González, Martha Elva; Karam-Calderón, Miguel Angel; Bustamante-Montes, L Patricia

    2015-09-01

    Studies on health behaviors have observed several barriers to breast cancer screening, including lack of breast cancer knowledge, distrust of health care providers, and long waiting times to be screened or to receive screening results. We conducted a nested case-control study among a subsample of 200 women 21 years of age and older [100 patients (cases)], who had been diagnosed with breast cancer, and 100 controls, who were screened and found to be free of breast cancer), all residing in the Toluca metropolitan area in central Mexico. We examined how knowledge of breast cancer screening guidelines, perceptions of screening methods, and quality of health care influenced the use of breast cancer screening among study participants. Our study found that the most important factor associated with the decision to have breast cancer screenings was having a positive perception of the quality of care provided by the local health care centers, such as having competent clinic personnel, sufficient screening equipment, and reasonable waiting times to receive screening and to receive the screening results. Therefore, individual health care centers need to focus on the patients' perception of the services received by optimizing the care provided and, in so doing, increase the rates of early diagnosis and reduce the rate of mortality from breast cancer as well as its associated treatment costs.

  1. Effectiveness of bats as pollinators of Stenocereus stellatus (Cactaceae) in wild, managed in situ, and cultivated populations in La Mixteca Baja, central Mexico.

    Science.gov (United States)

    Arias-Cóyotl, Ethel; Stoner, Kathryn E; Casas, Alejandro

    2006-11-01

    Stenocereus stellatus is an endemic, self-incompatible, columnar cactus found in central Mexico where many of its wild populations have been fragmented. As an economically important species of fruit-producing cactus, S. stellatus occurs in wild, managed in situ, and cultivated populations. The objectives of this study were to determine the effective pollinators of S. stellatus, to compare pollinator visits and reproductive parameters among the three types of populations, and to determine if nectar feeding-bats are moving among populations. Effective pollinators were the nectarivorous bats Choeronycteris mexicana, Leptonycteris curasoae, and L. nivalis. Fewer total visits per flower per night and fewer visits by Choeronycteris were observed in cultivated populations, while the opposite pattern was observed for Leptonycteris. One aggressive interaction was filmed in which Choeronycteris was physically displaced by Leptonycteris, and Choeronycteris visits were significantly affected by Leptonycteris visits. Cultivated populations received more pollen grains and had more fruit set. Variation in pollinator visits between different populations and the consequent effects on reproductive success were likely a result of competition between bat species, and differences in foraging and in sensitivity of bat species to human populations. Three marked L. curasoae traveled 15 km from their roosting site to their foraging area, and one visited cultivated and managed populations, suggesting that this species may be particularly important in moving pollen among populations.

  2. Resource Assessment of the In-Place and Potentially Recoverable Deep Natural Gas Resource of the Onshore Interior Salt Basins, North Central and Northeastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini; Donald A. Goddard

    2005-04-15

    The principal research effort for the first six months of Year 2 of the project has been petroleum system characterization. Understanding the burial and thermal maturation histories of the strata in the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas is important in petroleum system characterization. The underburden and overburden rocks in these basins and subbasins are a product of their rift-related geohistory. Petroleum source rock analysis and thermal maturation and hydrocarbon expulsion modeling indicate that an effective regional petroleum source rock in the onshore interior salt basins, the North Louisiana Salt Basin, Mississippi Interior Salt Basin, Manila Subbasin and Conecuh Subbasin, was the Upper Jurassic Smackover lime mudstone. The Upper Cretaceous Tuscaloosa shale was an effective local petroleum source rock in the Mississippi Interior Salt Basin and a possible local source bed in the North Louisiana Salt Basin. Hydrocarbon generation and expulsion was initiated in the Early Cretaceous and continued into the Tertiary in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin. Hydrocarbon generation and expulsion was initiated in the Late Cretaceous and continued into the Tertiary in the Manila Subbasin and Conecuh Subbasin. Reservoir rocks include Jurassic, Cretaceous and Tertiary siliciclastic and carbonate strata. Seal rocks include Jurassic, Cretaceous and Tertiary anhydrite and shale beds. Petroleum traps include structural and combination traps.

  3. Correlating Remote Sensing Data with the Abundance of Pupae of the Dengue Virus Mosquito Vector, Aedes aegypti, in Central Mexico

    Directory of Open Access Journals (Sweden)

    Max J. Moreno-Madriñán

    2014-05-01

    Full Text Available Using a geographic transect in Central Mexico, with an elevation/climate gradient, but uniformity in socio-economic conditions among study sites, this study evaluates the applicability of three widely-used remote sensing (RS products to link weather conditions with the local abundance of the dengue virus mosquito vector, Aedes aegypti (Ae. aegypti. Field-derived entomological measures included estimates for the percentage of premises with the presence of Ae. aegypti pupae and the abundance of Ae. aegypti pupae per premises. Data on mosquito abundance from field surveys were matched with RS data and analyzed for correlation. Daily daytime and nighttime land surface temperature (LST values were obtained from Moderate Resolution Imaging Spectroradiometer (MODIS/Aqua cloud-free images within the four weeks preceding the field survey. Tropical Rainfall Measuring Mission (TRMM-estimated rainfall accumulation was calculated for the four weeks preceding the field survey. Elevation was estimated through a digital elevation model (DEM. Strong correlations were found between mosquito abundance and RS-derived night LST, elevation and rainfall along the elevation/climate gradient. These findings show that RS data can be used to predict Ae. aegypti abundance, but further studies are needed to define the climatic and socio-economic conditions under which the correlations observed herein can be assumed to apply.

  4. Direct and indirect estimates of gene flow among wild and managed populations of Polaskia chichipe, an endemic columnar cactus in Central Mexico.

    Science.gov (United States)

    Otero-Arnaiz, Adriana; Casas, Alejandro; Hamrick, James L

    2005-12-01

    Microsatellite markers were used to obtain direct and indirect estimates of gene flow in populations of Polaskia chichipe under different management regimes, in order to understand the genetic consequences of gene flow in the evolutionary process of domestication. P. chichipe is a columnar cactus endemic to the Tehuacan Valley, Central Mexico, and has come under domestication for its edible fruit. Morphological, phenological, physiological, and reproductive differences, apparently attributable to artificial selection, exist between wild and managed populations, which grow sympatrically. However, strong gene flow may counteract the effects of this selection. In this study, we used paternity analysis to demonstrate that although most of the pollinations occur among individuals within the same population at distances < 40 m, pollen flow from other populations is considerable (27 +/- 5%). Heterogeneity in pollen clouds sampled by mother plants (FST = 0.12) indicated nonrandom mating, which is probably due to temporal heterogeneity in pollen movement. Spatial structure on local and regional scales is consistent with an isolation-by-distance model. The similarity of indirect, direct and demographic estimates of neighbourhood size (74-250 individuals) suggests that this genetic structure is representative of an equilibrium state. These results suggest that traditional management practices have conserved the genetic resources of this species in situ, but also that gene flow is counteracting the effect of domestication to some degree. We discuss our results in the general context of genetic exchange between cultivated and wild populations during the domestication process.

  5. Characterizing a deep freeze event in a creasote shrubland in central New Mexico using a combination of remote sensing and in-situ carbon flux measurements

    Science.gov (United States)

    Krofcheck, D. J.; Ladwig, L.; Litvak, M. E.; Pockman, W.

    2013-12-01

    In February 2011 temperatures on the Sevilleta LTER in central New Mexico dropped to -29 deg C (roughly a 25-50 year minimum temperature), resulting in the widespread, differential mortality of creasote bush (Larrea tridentata) across the region. The sudden loss of leaf area was followed by patchy regrowth of the vegetation about three months following the freeze, at the onset of warmer temperatures. The summer of 2011 then marked the onset of a significant drought which further suppressed the recovery of the shrubland. We took advantage of a combination of phenocam and eddy-covariance data sets to characterize the patterns in carbon and energy flux prior to and following the mortality and recovery of this ecosystem during severe drought conditions across the Sevilleta LTER. We also leveraged a time series of high resolution satellite images (5 x 5 meters, 5 spectral bands) from RapidEye to upscale our local measurements of ecosystem structural and functional change to the region. This case study provides valuable insight into how woody shrublands may respond to combinations of intense climatic disturbance that are projected to become more frequent and severe.

  6. KEY ROLE OF METALLOGENIC THEORY OF POLYGENETIC COMPOUND ORE DEPOSITS IN LOCATION PREDICTION OF HIDDEN ORE DEPOSITS IN DIWA REGIONS

    Institute of Scientific and Technical Information of China (English)

    PENG; Sheng-lin; LIU; Liang-ming; LAI; Jian-qing

    2001-01-01

    The metallogenic theory of polygenetic compound ore deposit is the Important basis for location prediction of hidden ore deposits in diwa regions.It can play an important role in each step of prediction research,targeting procedure,acquiring information and integrating information.In this paper,the authors discusses how to construct geological concept by using of the metallogenic theory of polygenetic ore deposits for predicting targeting area,to arrange investigation and detection for getting enough useful information,and to analyze and integrate information for reaching a trustful prediction conclusion.According to these strategies,we conduct a successful prediction of location of hidden ore bodies in the outer of the Fenghuangshan copper mine,a principal producing mine in Tongling Cu-Au district.

  7. Mineral Chemistry and Boron Isotopic Composition of Tourmaline from the Devonian Metallogenic District of Shanyang-Zhashui,Eastern Qinling

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    Tourmaline is widespread in the host strata of strata-bound base metal sulphide deposits in the Devonian metallogenic deistrict around Shanyang-Zhashui in eastern Qinling,As a member of the schorl-dravite series,the tourmaline is characterized by Mg>Fe and Na>Ca,showing apparent chemical zonation which records the geochemistry during its formation and subsequent regional metamorphism and hydrothermal overprint.The close similarity in chemical and isotopic constitutions between the tourmaline of the main metallogenic epoch in this district [FeO/(FeO_MgO)=0.34-0.39and δ11B=-7.6‰--8.8‰] and those related to massive sulphide deposits typical of submarine(exhalative)hydrothermal sedimentation may add further support to a similar mechanism of mineralization for strata-bound depostis in the district.

  8. The structural architecture of the Los Humeros volcanic complex and geothermal field, Trans-Mexican Volcanic Belt, Central Mexico

    Science.gov (United States)

    Norini, Gianluca; Groppelli, Gianluca; Sulpizio, Roberto; Carrasco Núñez, Gerardo; Davila Harris, Pablo

    2014-05-01

    The development of geothermal energy in Mexico is a very important goal, given the presence of a large heat anomaly, associated with the Trans-Mexican Volcanic Belt, the renewability of the resource and the low environmental impact. The Quaternary Los Humeros volcanic complex is an important geothermal target, whose evolution involved at least two caldera events, that alternated with other explosive and effusive activity. The first caldera forming event was the 460 ka eruption that produced the Xaltipan ignimbrite and formed a 15-20 km wide caldera. The second collapse event occurred 100 ka with the formation of the Zaragoza ignimbrite and a nested 8-10 km wide caldera. The whole volcano structure, the style of the collapses and the exact location of the calderas scarps and ring faults are still a matter of debate. The Los Humeros volcano hosts the productive Los Humeros Geothermal Field, with an installed capacity of 40 MW and additional 75 MW power plants under construction. Recent models of the geothermal reservoir predict the existence of at least two reservoirs in the geothermal system, separated by impermeable rock units. Hydraulic connectivity and hydrothermal fluids circulation occurs through faults and fractures, allowing deep steam to ascend while condensate flows descend. As a consequence, the plans for the exploration and exploitation of the geothermal reservoir have been based on the identification of the main channels for the circulation of hydrothermal fluids, constituted by faults, so that the full comprehension of the structural architecture of the caldera is crucial to improve the efficiency and minimize the costs of the geothermal field operation. In this study, we present an analysis of the Los Humeros volcanic complex focused on the Quaternary tectonic and volcanotectonics features, like fault scarps and aligned/elongated monogenetic volcanic centres. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of

  9. Tepexpan revisited: A multiple proxy of local environmental changes in relation to human occupation from a paleolake shore section in Central Mexico

    Science.gov (United States)

    Sedov, Sergey; Lozano-García, Socorro; Solleiro-Rebolledo, Elizabeth; McClung de Tapia, Emily; Ortega-Guerrero, Beatriz; Sosa-Nájera, Susana

    2010-10-01

    Building up a scenario of Late Pleistocene-Holocene environmental change and human-landscape interactions in Central Mexico - one of the key areas for the natural and cultural history of America - requires development of local paleoenvironmental reconstructions. We studied the Tepexpan section at the edge of Texcoco a paleolake, near the mouth of Teotihuacan Valley as a multiproxy record of the environmental dynamics at the shore in the Basin of Mexico throughout the period of human occupation. The section is located in an ecotone affected by intensive and variable geomorphic processes and includes lacustrine, fluvial and volcanic sediments as well as paleosols. Our chronological scale is based on 6 AMS 14C dates from pollen concentrates and paleosol organic matter. The lower segment of the section dominated by the lacustrine sediments yielded pollen spectra; in the upper segment the record is based on the pedogenetic characteristics of paleosols. Different proxies agree in demonstrating the general trend (although some reversals are apparent) of decreasing effective moisture since MIS3: it is reflected first in the increase of herbaceous pollen after 27 ka BP, the decrease of lake level, the cessation of lacustrine sedimentation and beginning of marsh soil development at 10 ka BP and finally, the shift from hydromorphic to dryland semiarid pedogenesis in the Late Holocene. We assume that this trend was climatically controlled, whereas the deposition of sedimentary layers enriched with tephra are related to the pulses of volcanic activity; the pedosedimentary features associated with the upper soil are human-induced. Comparing the proposed scheme of environmental change with the archaeological record we propose that the initial settlers, Late Paleolithic hunters, could have utilized the wet swampy meadows which expanded on the Basin bottom as the lake level lowered and provided the niche for large herbivores during the Pleistocene-Holocene transition. Development

  10. Strain Localisation at Rift Segment Boundaries: An Example from the Bocana Transfer Zone in Central Baja California, Mexico

    Science.gov (United States)

    Seiler, C.; Gleadow, A. J.; Kohn, B. P.

    2012-12-01

    Rifts are commonly segmented into several hundred kilometre long zones of opposing upper-plate transport direction with boundaries defined by accommodation and transfer zones. A number of such rift segments have been recognized in the northern Gulf of California, a youthful oceanic basin that is currently undergoing the rift-drift transition. However, detailed field studies have so far failed to identify suitable structures that could accommodate the obvious deformation gradients between different rift segments, and the nature of strain transfer at segment boundaries remains enigmatic. The situation is even less clear in central and southern Baja California, where a number of rift segments have been hypothesized but it is unknown whether the intervening segment boundaries facilitate true reversals in the upper-plate transport direction, or whether they simply accommodate differences in the timing, style or magnitude of deformation. The Bocana transfer zone (BTZ) in central Baja California is a linear, WNW-ESE striking structural discontinuity separating two rift segments with different magnitudes and styles of extensional deformation. North of the BTZ, the Libertad fault is part of the Main Gulf Escarpment, which represents the breakaway fault that separates the Gulf of California rift to the east from the relatively stable western portion of the Baja peninsula. The N-striking Libertad escarpment developed during the Late Miocene (~10-8Ma) and exhibits a topographic relief of ca. 1,000m along a strike-length of ca. 50km. Finite displacement decreases from ~1000m in the central fault segment to ~500m further south, where the fault bends SE and merges with the BTZ. In the hanging wall of the Libertad fault, a series of W-tilted horsts are bound along their eastern margins by two moderate-displacement E-dipping normal faults. South of the BTZ, extension was much less than further north, which explains the comparatively subdued relief and generally shallower tilt of

  11. Can government be self-organized? A mathematical model of the collective social organization of ancient Teotihuacan, central Mexico.

    Directory of Open Access Journals (Sweden)

    Tom Froese

    Full Text Available Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city's origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city's hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city's eventual disintegration.

  12. Can Government Be Self-Organized? A Mathematical Model of the Collective Social Organization of Ancient Teotihuacan, Central Mexico

    Science.gov (United States)

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R.

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city’s origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city’s hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city’s eventual disintegration. PMID:25303308

  13. Can government be self-organized? A mathematical model of the collective social organization of ancient Teotihuacan, central Mexico.

    Science.gov (United States)

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city's origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city's hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city's eventual disintegration.

  14. Geophysical Exploration of Fractured-Media Aquifers at the Mexican Mesa Central: Satellite City, San Luis Potosí, Mexico

    Science.gov (United States)

    López Loera, Héctor; Ramos Leal, José Alfredo; Dávila Harris, Pablo; Torres Gaytan, David Ernesto; Martinez Ruiz, Victor Julian; Gogichaishvili, Avto

    2015-01-01

    Groundwater is scarce in arid and semi-arid zones in the Mexican Mesa Central. It is found at depths over 200 m, and its movement is primarily through fractures. This work aims to present a geophysical methodology, which shows the potential of combining natural and induced methods to locate confined aquifers in fault zones. The studies begin by interpreting the aeromagnetic survey, mainly by seeking lineaments associated with low magnetic anomalies, which are correlated with fault zones, and/or fractures and/or geological contacts where ferromagnetic minerals have undergone oxidation due to their association with recharge zones. These aeromagnetic lineaments are confirmed on land by a ground magnetic survey. After locating these areas, interpreted as permeability zones, their possible association with moist zones is confirmed by applying the vertical electrical sounding (VES) technique. H-type curve is associated with the presence of saturated zones. This study used the proposed methodology to interpret four main aeromagnetic lineaments and 12 main ground magnetic lineaments in a 36 km2 (6 km × 6 km) area. Twenty-six SEV were performed over these magnetic lineaments, of which about 50 % were associated with H-type resistivity curves, interpreted as being associated with moisture. Of the 12 VES with inferred groundwater potential, two wells have been drilled to date, one having an extraction flow of 70 lps.

  15. Chemical and Physical Characteristics of Sediments from Prevalent Dust Sources in the Central Chihuahuan Desert, Chihuahua, Mexico

    Science.gov (United States)

    Dominguez Acosta, M.; Gill, T. E.; Peinado, P.

    2013-05-01

    The Chihuahuan Desert has been recognized as an important contributor of mineral aerosols emplaced into the atmosphere in the Western Hemisphere. Along with the production of these aerosols, growing concern has been stated relating the downwind transport of atmospheric dust particles to increases in human health related impacts such as asthma and bronchitis in the Binational Paso Del Norte, the largest urban area in the region. Efforts have been made to describe the source types (land use/cover) and frequency of emission from the "dust hotspots" or prevalent sources within the region. These studies have outlined specific areas and their related sedimentological environments responsible for the regular dust production. Ephemeral lakes, fluvial and alluvial related environments form the main natural dust producing landforms in the region, modulated by short-term climatic variability and anthropogenic disturbance. Analysis of remote sensing imagery shows that the margins between natural areas and agricultural lands form the main anthropogenic related source areas. Most of the previously published studies focus on these remotely sensed descriptions of the dust sources, while only a few deal with in situ or field characteristics of these sources. A formal and detailed description of the physicochemical properties of many of these areas is presented, providing key data on this component of the overall dust production cycle. Elemental and mineralogical compositions of dust source sediments, soil textural compositions (grain size distributions) and field sedimentological descriptions are presented as an effort to attain a detailed in situ description of the prevalent dust sources in the central part of the Chihuahuan Desert.

  16. Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico, and Texas : shallow ground-water quality and land use in the Albuquerque area, central New Mexico, 1993

    Science.gov (United States)

    Anderholm, Scott K.

    1997-01-01

    This report describes the quality of shallow ground water and the relations between land use and the quality of that shallow ground water in an urban area in and adjacent to Albuquerque, New Mexico. Water samples were collected from 24 shallow wells. Samples were analyzed for selected common constituents, nutrients, trace elements, radionuclides, volatile organic compounds, and pesticides. The study area, which is in the Albuquerque Basin in central New Mexico, was limited to the Rio Grande flood plain; depth to water in this area generally is less than 25 feet. The amount and composition of recharge to the shallow ground-water system are important factors that affect shallow ground-water composition in this area. Important sources of recharge that affect shallow ground-water quality in the area include infiltration of surface water, which is used in agricultural land-use areas to irrigate crops, and infiltration of septic-system effluent in residential areas. Agricultural land use represents about 28 percent of the area, and residential land use represents about 35 percent of the total study area. In most of the study area, agricultural land use is interspersed with residential land use and neither is the dominant land use in the area. Land use in the study area historically has been changing from agricultural to urban. The composition of shallow ground water in the study area varies considerably. The dissolved solids concentration in shallow ground water in the study area ranges from 272 to 1,650 milligrams per liter, although the relative percentages of selected cations and anions do not vary substantially. Calcium generally is the dominant cation and bicarbonate generally is the dominant anion. Concentrations of nutrients generally were less than 1 milligram per liter. The concentration of many trace elements in shallow ground water was below or slightly above 1 microgram per liter and there was little variation in the concentrations. Barium, iron, manganese

  17. Postwildfire preliminary debris flow hazard assessment for the area burned by the 2011 Las Conchas Fire in north-central New Mexico

    Science.gov (United States)

    Tillery, Anne C.; Darr, Michael J.; Cannon, Susan H.; Michael, John A.

    2011-01-01

    The Las Conchas Fire during the summer of 2011 was the largest in recorded history for the state of New Mexico, burning 634 square kilometers in the Jemez Mountains of north-central New Mexico. The burned landscape is now at risk of damage from postwildfire erosion, such as that caused by debris flows and flash floods. This report presents a preliminary hazard assessment of the debris-flow potential from 321 basins burned by the Las Conchas Fire. A pair of empirical hazard-assessment models developed using data from recently burned basins throughout the intermountain western United States was used to estimate the probability of debris-flow occurrence and volume of debris flows at the outlets of selected drainage basins within the burned area. The models incorporate measures of burn severity, topography, soils, and storm rainfall to estimate the probability and volume of debris flows following the fire. In response to a design storm of 28.0 millimeters of rain in 30 minutes (10-year recurrence interval), the probabilities of debris flows estimated for basins burned by the Las Conchas Fire were greater than 80 percent for two-thirds (67 percent) of the modeled basins. Basins with a high (greater than 80 percent) probability of debris-flow occurrence were concentrated in tributaries to Santa Clara and Rio del Oso Canyons in the northeastern part of the burned area; some steep areas in the Valles Caldera National Preserve, Los Alamos, and Guaje Canyons in the east-central part of the burned area; tributaries to Peralta, Colle, Bland, and Cochiti canyons in the southwestern part of the burned area; and tributaries to Frijoles, Alamo, and Capulin Canyons in the southeastern part of the burned area (within Bandelier National Monument). Estimated debris-flow volumes ranged from 400 cubic meters to greater than 72,000 cubic meters. The largest volumes (greater than 40,000 cubic meters) were estimated for basins in Santa Clara, Los Alamos, and Water Canyons, and for two

  18. RESOURCE ASSESSMENT OF THE IN-PLACE AND POTENTIALLY RECOVERABLE DEEP NATURAL GAS RESOURCE OF THE ONSHORE INTERIOR SALT BASINS, NORTH CENTRAL AND NORTHEASTERN GULF OF MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini

    2004-04-16

    The University of Alabama and Louisiana State University have undertaken a cooperative 3-year, advanced subsurface methodology resource assessment project, involving petroleum system identification, characterization and modeling, to facilitate exploration for a potential major source of natural gas that is deeply buried (below 15,000 feet) in the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas. The project is designed to assist in the formulation of advanced exploration strategies for funding and maximizing the recovery from deep natural gas domestic resources at reduced costs and risks and with minimum impact. The results of the project should serve to enhance exploration efforts by domestic companies in their search for new petroleum resources, especially those deeply buried (below 15,000 feet) natural gas resources, and should support the domestic industry's endeavor to provide an increase in reliable and affordable supplies of fossil fuels. The principal research effort for Year 1 of the project is data compilation and petroleum system identification. The research focus for the first nine (9) months of Year 1 is on data compilation and for the remainder of the year the emphasis is on petroleum system identification. The objectives of the study are: to perform resource assessment of the in-place deep (>15,000 ft) natural gas resource of the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas through petroleum system identification, characterization and modeling and to use the petroleum system based resource assessment to estimate the volume of the in-place deep gas resource that is potentially recoverable and to identify those areas in the interior salt basins with high potential to recover commercial quantities of the deep gas resource. The project objectives will be achieved through a 3-year effort. First, emphasis is on petroleum system identification and characterization in the

  19. Paleomagnetic secular variation study of Ar-Ar dated lavas flows from Tacambaro area (Central Mexico): Possible evidence of Intra-Jaramillo geomagnetic excursion in volcanic rocks

    Science.gov (United States)

    Peña, Rafael Maciel; Goguitchaichvili, Avto; Guilbaud, Marie-Noëlle; Martínez, Vicente Carlos Ruiz; Rathert, Manuel Calvo; Siebe, Claus; Reyes, Bertha Aguilar; Morales, Juan

    2014-04-01

    More than 350 oriented paleomagnetic cores were obtained for rock-magnetic and paleomagnetic analysis from radiometrically dated (40Ar-39Ar) magmatic rocks occurring in the southern segment (Jorullo and Tacámbaro areas) of the Michoacán-Guanajuato Volcanic Field in the Trans-Mexican Volcanic Belt. Most of the lavas (37) stem from monogenetic volcanoes dated at less than 4 Ma. Two additional sites were sampled from the plutonic basement dated at 33-30 Ma. Primary remanences carried by low-Ti titanomagnetites allowed to determining 34 reliable site-mean directions of mostly normal (27) but also reversed (7) polarities. The mean directions of these two populations are antipodal, and suggest neither major vertical-axis rotations with respect to the North America craton nor tilting in the region for the last 4 Ma (rotation and flattening of the inclination parameters being less than -5.9 ± 3.8 and 0.1 ± 3.9, respectively). The corresponding paleomagnetic pole obtained for Pliocene-Pleistocene times is PLAT = 83.4°, PLON = 2.4° (N = 32, A95 = 2.7°). Virtual geomagnetic poles also contribute to the time averaged field global database and to the paleosecular variation (PSV) investigations at low latitudes from lavas for the last 5 Ma, showing a geomagnetic dispersion value that is in agreement with available PSV models. When comparing the magnetic polarities and corresponding radiometric ages of the studied sites with the Cenozoic geomagnetic polarity time scale (GPTS), a good correlation is observable. This finding underscores the suitability of data obtained on lavas in Central Mexico for contributing to the GPTS. Furthermore, the detection of short-lived geomagnetic features seems possible, since the possible evidence of Intra-Jaramillo geomagnetic excursion could be documented for the first time in these volcanic rocks.

  20. Pre-eruptive conditions of dacitic magma erupted during the 21.7 ka Plinian event at Nevado de Toluca volcano, Central Mexico

    Science.gov (United States)

    Arce, J. L.; Gardner, J. E.; Macías, J. L.

    2013-01-01

    The Nevado de Toluca volcano in Central Mexico has been active over the last ca. 42 ka, during which tens of km3 of pyroclastic material were erupted and two important Plinian-type eruptions occurred at ca. 21.7 ka (Lower Toluca Pumice: LTP) and ca. 10.5 ka (Upper Toluca Pumice: UTP). Samples from both the LTP and UTP contain plagioclase, amphibole, iron-titanium oxides, and minor anhedral biotite, set in a vesicular, rhyolitic, glassy matrix. In addition, UTP dacites contain orthopyroxene. Analysis of melt inclusions in plagioclase phenocrysts yields H2O contents of 2-3.5 wt.% for LTP and 1.3-3.6 wt.% for UTP samples. Ilmenite-ulvospinel geothermometry yields an average temperature of ~ 868 °C for the LTP magma (hotter than the UTP magma, ~ 842 °C; Arce et al., 2006), whereas amphibole-plagioclase geothermometry yields a temperature of 825-859 °C for the LTP magma. Water-saturated experiments using LTP dacite suggest that: (i) amphibole is stable above 100 MPa and below 900 °C; (ii) plagioclase crystallizes below 250-100 MPa at temperatures of 850-900 °C; and (iii) pyroxene is stable only below pressures of 200-100 MPa and temperatures of 825-900 °C. Comparison of natural and experimental data suggests that the LTP dacitic magma was stored at 150-200 MPa (5.8-7.7 km below the volcano summit). No differences in pressure found between 21.7 ka and 10.5 ka suggest that these two magmas were stored at similar depths. Orthopyroxene produced in lower temperature LTP experiments is compositionally different to those found in UTP natural samples, suggesting that they originated in two different magma batches. Whole-rock chemistry, petrographic features, and mineral compositions suggest that magma mixing was responsible for the generation of the dacitic Plinian LTP eruption.

  1. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2015

    Science.gov (United States)

    Beman, Joseph E.; Bryant, Christina F.

    2016-10-27

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is hydrologically defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift between San Acacia to the south and Cochiti Lake to the north. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) began treatment and distribution of surface water from the Rio Grande through the San Juan-Chama Drinking Water Project. A 20-percent population increase in the basin from 1990 to 2000 and a 22-percent population increase from 2000 to 2010 may have resulted in an increased demand for water in areas within the basin.An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the Albuquerque Basin. In 1983, this network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. The network currently (2015) consists of 124 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the ABCWUA, currently (2015) measures and reports water levels from the 124 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 124 sites through water year 2015 (October 1, 2014, through September 30, 2015).

  2. A detailed paleomagnetic and rock-magnetic investigation of the Matuyama-Bruhnes geomagnetic reversal recorded in tephra-paleosol sequence of Tlaxcala(Central Mexico)

    Science.gov (United States)

    Soler-Arechalde, Ana; Goguitchaichvili, Avtandyl; Carrancho, Ángel; Sedov, Sergey; Caballero-Miranda, Cecilia; Ortega, Beatriz; Solís, Berenice; Morales Contreras, Juan; Urrutia-Fucugauchi, Jaime; Bautista, Francisco

    2015-04-01

    Geomagnetic reversals are global phenomena, for about 50 years the paleomagnetists attempted to acquire as many detailed records as possible using the magnetic memory of sediments and lava flows. Yet, transitional field behavior remains poorly characterized largely because of sporadic aspect of volcanic eruptions. In some specific cases, paleosols such as those developed from alluvial or aeolian sediments, may also record the variations of the Geomagnetic Field across the polarity changes. Here, we report a detailed paleomagnetic and rock-magnetic investigation on some radiometrically dated chromic luvisols located in Central Mexico carrying detrital or chemical remanent magnetization. The research was developed in order i) to demonstrate the primary origin of the magnetic remanence and ii) to show that paleosoils are good candidates to provide a high resolution record of the behavior of geomagnetic field during reversals. The lower part of the paleosoil sequence shows a clearly defined reverse polarity magnetization followed by geomagnetically unstable transitional field and ended by normal polarity remanence. Our AMS and rock magnetic data suggest that magnetization is acquired during the initial stage of soil formation in context of active volcanic activity since magnetic fabric is essentially sedimentary and reverse and normal polarity paleodirections are almost antipodal. Titanomagnetites are identified as main magnetic carriers of rock-magnetic measurements including thermomagnetics and hysteresis cycles. We propose that the transition recorded in this study correspond to the B-M boundary, considering the K-Ar datings available at the sequence bottom and that the chromic luvisols are potentially good recorders of the paleosecular variation. The identification of the B-M boundary within the studied sequence has fundamental significance for improving the chronological scale of Tlaxcala paleosol-sedimentary sequence and its correlation with the global proxies.

  3. A detailed paleomagnetic and rock-magnetic investigation of the Matuyama-Bruhnes geomagnetic reversal recorded in tephra-paleosol sequence of Tlaxcala(Central Mexico

    Directory of Open Access Journals (Sweden)

    Ana Maria Soler-Arechalde

    2015-04-01

    Full Text Available Geomagnetic reversals are global phenomena, for about 50 years the paleomagnetists attempted to acquire as many detailed records as possible using the magnetic memory of sediments and lava flows. Yet, transitional field behavior remains poorly characterized largely because of sporadic aspect of volcanic eruptions. In some specific cases, paleosols such as those developed from alluvial or aeolian sediments, may also record the variations of the Geomagnetic Field across the polarity changes. Here, we report a detailed paleomagnetic and rock-magnetic investigation on some radiometrically dated chromic luvisols located in Central Mexico carrying detrital or chemical remanent magnetization. The research was developed in order i to demonstrate the primary origin of the magnetic remanence and ii to show that paleosoils are good candidates to provide a high resolution record of the behavior of geomagnetic field during reversals. The lower part of the paleosoil sequence shows a clearly defined reverse polarity magnetization followed by geomagnetically unstable transitional field and ended by normal polarity remanence. Our AMS and rock magnetic data suggest that magnetization is acquired during the initial stage of soil formation in context of active volcanic activity since magnetic fabric is essentially sedimentary and reverse and normal polarity paleodirections are almost antipodal. Titanomagnetites are identified as main magnetic carriers of rock-magnetic measurements including thermomagnetics and hysteresis cycles. We propose that the transition recorded in this study correspond to the B-M boundary, considering the K-Ar datings available at the sequence bottom and that the chromic luvisols are potentially good recorders of the paleosecular variation. The identification of the B-M boundary within the studied sequence has fundamental significance for improving the chronological scale of Tlaxcala paleosol-sedimentary sequence and its correlation with the

  4. The implications of geology, soils, and vegetation on landscape morphology: Inferences from semi-arid basins with complex vegetation patterns in Central New Mexico, USA

    Science.gov (United States)

    Yetemen, Omer; Istanbulluoglu, Erkan; Vivoni, Enrique R.

    2010-04-01

    This paper examines the relationship between land surface properties (e.g. soil, vegetation, and lithology) and landscape morphology quantified by the catchment descriptors: the slope-area (S-A) relation, curvature-area (C-A) relation, and the cumulative area distribution (CAD), in two semi-arid basins in central New Mexico. The first site is composed of several basins located in today's desert elevations with mesic north-facing and xeric south-facing hillslopes underlain by different lithological formations. The second site is a mountainous basin exhibiting vegetation gradients from shrublands in the lower elevations to grasslands and forests at higher elevations. All three land surface properties were found to have significant influences on the S-A and C- A relations, while the power-law exponents of the CADs for these properties did not show any significant deviations from the narrow range of universal scaling exponents reported in the literature. Among the three different surface properties we investigated, vegetation had the most profound impact on the catchment descriptors. In the S-A diagrams of the aspect-controlled ecosystems, we found steeper slopes in north-facing aspects than south-facing aspects for a given drainage area. In elevation-controlled ecosystems, forested landscapes exhibited the steepest slopes for the range of drainage areas examined, followed by shrublands and grasslands in all soil textures and lithologies. In the C-A diagrams, steeper slopes led to a higher degree of divergence on hillslopes and a higher degree of convergence in the valleys than shallower slopes. The influence of functional types of vegetation detected on observed topography provided some initial understanding of the potential impacts of life on the organization of topography. This finding also emphasizes the critical role of climate in catchment development. We suggest that climatic fluctuations that are capable of replacing vegetation communities could lead to highly

  5. Mechanical stability model of progradational carbonate platform margins under tectonic loads: Deformation of Cretaceous carbonate platforms in the Sierra Madre Oriental fold-thrust belt (east central Mexico)

    Science.gov (United States)

    Contreras, Juan; Suter, Max

    2015-02-01

    Shortening in the Sierra Madre Oriental fold-thrust belt (east central Mexico) is localized along the margins of Cretaceous carbonate platforms and controlled by mechanical stratigraphy. The platform margins are deformed by imbricate series of thrust ramps, whereas the coeval basins and platform interiors are deformed by map-scale detachment folds. Here we present a finite element model to evaluate the influence of the boundary geometry and boundary conditions on the style of deformation observed at these basinward progradational platform margins. We calculate the stress distribution in a linearly elastic platform-basin transition zone under the action of horizontal tectonic stress, taking into account changes of rock mechanical properties across the platform margin, as well as their dependence on direction, and infer the resulting fracture patterns based on the Mohr-Coulomb failure criterion. Stress concentrations are predicted at the contacts between the massive rocks of the platform margin and the well-layered rocks of both, the platform interior and the adjacent basin. Brittle failure of the platform border can be mostly attributed to three effects: mechanical coupling between the carbonate platform and a substratum of moderate to low viscosity, variations in layering and texture that governed the mechanical properties of the involved carbonates as well as their dependence on direction, and the development of sharp domain boundary corners associated with progradational facies changes. In contrast, the dip of the basement and a possible taper of the overlying Upper Cretaceous shale toward the basin appear to have little influence on the mechanical failure of the platform margin.

  6. A GIS-based methodology for highlighting fuelwood supply/demand imbalances at the local level: A case study for Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ghilardi, Adrian; Guerrero, Gabriela; Masera, Omar [CIECO, Center for Ecosystems Research, Universidad Nacional Autonoma de Mexico, Antigua carretera a Patzcuaro 8701, 58 190 Morelia (Mexico)

    2009-06-15

    When fuelwood is harvested at a rate exceeding natural growth and inefficient conversion technologies are used, negative environmental and socio-economic impacts, such as fuelwood shortages, natural forests degradation and net GHG emissions arise. In this study, we argue that analyzing fuelwood supply/demand spatial patterns require multi-scale approaches to effectively bridge the gap between national results with local situations. The proposed methodology is expected to help 1) focusing resources and actions on local critical situations, starting from national wide analyses and 2) estimating, within statistically robust confidence bounds, the proportion of non-renewable harvested fuelwood. Starting from a previous work, we selected a county-based fuelwood hot spot in the Central Highlands of Mexico, identified from a national wide assessment, and developed a grid-based model in order to identify single localities that face concomitant conditions of high fuelwood consumption and insufficient fuelwood resources. By means of a multi-criteria analysis (MCA), twenty localities, out of a total of 90, were identified as critical in terms of six indicators related to fuelwood use and availability of fuelwood resources. Fuelwood supply/demand balances varied among localities from -16.2 {+-} 2.5 Gg y{sup -1} to 4.4 {+-} 2.6 Gg y{sup -1}, while fractions of non-renewable fuelwood varied from 0 to 96%. These results support the idea that balances and non-renewable fuelwood fractions (mandatory inputs for Clean Development Mechanism (CDM) cookstoves projects) must be calculated on a locality by locality basis if gross under or over-estimations want to be avoided in the final carbon accounting. (author)

  7. Mineral Potential Mapping for Tungsten Polymetallic Deposits in the Nanling Metallogenic Belt, South China

    Institute of Scientific and Technical Information of China (English)

    Yue Liu; Qiuming Cheng; Qinglin Xia; Xinqing Wang

    2014-01-01

    The Nanling belt in South China has considerable resources of tungsten polymetallic commodities and is one of the most important metallogenic belts in the world. Data-driven weights-of-evidence (WofE) and fuzzy logic models are used to evaluate the tungsten polymetallic po-tential of the Nanling belt. Initially, seven ore-controlling factors derived from multi-source geospatial datasets (e.g., geological, geochemical, and geophysical) are used for data integration in the two models. Two mineral potential maps are generated that efficiently predicate the locations of the deposits. The WofE map predicate 81%of the deposits within 13.6%of the study area, whereas the fuzzy logic map predicate 81.5%of the deposits within 13%of the area. The predictive maps are syntheses of spatial association rules, which provide better understanding of those factors that control the distribution of mineralization and trigger eventual exploration work in new areas. Subsequently, in order to evaluate the success rate accuracy, the receiver operating characteristic curves and area under the curves (AUCs) for the two potential maps are constructed. The results show that the AUCs for the WofE and fuzzy logic models are 0.775 7 and 0.840 6, respectively. The higher AUC value for the fuzzy logic model implies that it delineate a greater number of favorable areas compared with the WofE model. Overall, the capabilities of both models for correctly classifying areas with existing mineral deposits are satisfactory.

  8. The characteristics, origins, and geodynamic settings of supergiant gold metallogenic provinces

    Institute of Scientific and Technical Information of China (English)

    Robert; Kerrich[1; Richard; Goldfarb[2; David; Groves[3; Steven; Garwin[4

    2000-01-01

    There are six distinct classes of gold deposits, each represented by metallogenic provinces, having 100’s to > 1 000 tonne gold production. The deposit classes are: (1) erogenic gold; (2) Carlin and Carlin-like gold deposits; (3) epithermal gold-silver deposits; (4) copper-gold porphyry deposits; (5) iron-oxide copper-gold deposits; and (6) gold-rich volcanic hosted massive sul-fide (VMS) to sedimentary exhalative (SEDEX) deposits. This classification is based on ore and alteration mineral assemblages; ore and alteration metal budgets; ore fluid pressure(s) and compositions; crustal depth or depth ranges of formation; relationship to structures and/or magmatic intrusions at a variety of scales; and relationship to the P-T-t evolution of the host terrane. These classes reflect distinct geodynamic settings. Orogenic gold deposits are generated at mid-crustal (4-16 km) levels proximal to terrane boundaries, in transpressional subduction-accretion complexes of Cordilleran style erogenic belts; other orogeni

  9. Copper-Polymetal Metallogenic Series and Prospecting Perspective of Eastern Section of Gangdise

    Institute of Scientific and Technical Information of China (English)

    Zheng Youye; Xue Yingxi; Gao Shunbao

    2003-01-01

    Geological, geophysical, geochemical and remote sensing comprehensive studies show that big ore-prospecting potentiality is contained in the eastern section of the Gangdise Mountains, Tibet.There are various mineralization types with dominant types of porphyry and exhalation. According to their relations with tectonic evolution, they are divided into four kinds of metallogenic series as follows:magmatic type (Cr, Pt, Cu, Ni) and exhalation type (Cu, Pb, Zn, Ag) ore deposit series related to Neo-Tethys oceanic crust subduction action (125-96 Ma); epithermal type (Au, Ag, Pb, Zn, Sb), altered fractured rock type (Cu, Mo) and skarn rock type (Cu) ore deposit series related to arc-continental collision; porphyry type (Cu, Mo), cryptoexplosion breccia type (Cu, Au, Pb, Zn), shear zone type (Au, Ag, Sb) and skarn rock type (Cu, Fe) ore deposit series with relation to post-orogenic extensional strike-slip. From subductive complex to the north, zoning appears to be crystallization differentiation type (segregation type)-shear zone type (altered rock type)-skarn rock type, epithermal type-porphyry type-porphyry type and exhalation type-exhalation type-hydrothermal filling-replacement type.The ore deposit is characterized by multi-places from the same source, parity and multi-stage, hypabyssal rock from the deep source and poly genetic compound as a whole.

  10. Children’s Migration to the United States from Mexico and Central America: Evidence from the Mexican and Latin American Migration Projects

    OpenAIRE

    Donato, Katharine M.; Blake Sisk

    2015-01-01

    In light of rising numbers of unaccompanied minors at the Mexico-US border in 2014, this article examines child migration from Mexico, Guatemala, El Salvador, Costa Rica, and Nicaragua. Using data from the Mexican and Latin American Migration Projects that permit us to go beyond simple descriptive analysis about children apprehended at the border, we investigate the extent to which children from these countries: (1) enter without legal authorization to do so; (2) are more likely to cross the ...

  11. From Drug Wars to Criminal Insurgency: Mexican Cartels, Criminal Enclaves and Criminal Insurgency in Mexico and Central America. Implications for Global Security

    OpenAIRE

    Sullivan, John P.

    2011-01-01

    Transnational organized crime is a pressing global security issue. Mexico is currently embroiled in a protracted drug war. Mexican drug cartels and allied gangs (actually poly-crime organizations) are currently challenging states and sub-state polities (in Mexico, Guatemala, El Salvador and beyond) to capitalize on lucrative illicit global economic markets. As a consequence of the exploitation of these global economic flows, the cartels are waging war on each other and state institutions to g...

  12. Cyanobacteria/Foraminifera Association from Anoxic/Dysoxic Beds of the Agua Nueva Formation (Upper Cretaceous - Cenomanian/Turonian) at Xilitla, San Luis Potosi, Central Mexico

    Science.gov (United States)

    Blanco-Piñón, A.; Maurrasse, F. J.; Rojas-León, A.; Duque-Botero, F.

    2008-05-01

    The Agua Nueva Formation in the vicinity of Xilitla, State of San Luis Potosí, Central Mexico, consists of interbedded brown shale (Grayish orange 10YR 7/4 to Moderate yellowish brown 10YR 5/4) and dark-gray fossiliferous limestone (Bluish gray 5B 6/1 to Dark bluish gray 5B 4/1), varying between 10 and 20 cm in thickness. The sequence also includes 2 to 4 cm- thick intermittent bentonite layers (Moderate greenish yellow 10Y 7/4, to dark greenish yellow 10Y 6/6 and Light olive 10Y 5/4). At the field scale, shaly intervals show no apparent internal structures, whereas most limestone beds show primary lamination at the millimeter scale (1-2 mm), and intermittent layers of black chert of about 5 cm thick. Pyrite is present as disseminated crystals and as 2 cm-thick layers. Bioturbation or macrobenthic organisms other than inoceramids do not occur in the Agua Nueva Formation at Xilitla. Unusual macrofossils are present only in limestone strata, and consist of well- preserved diverse genera of fishes such as sharks, Ptychodus sp. and teleosteans, Rhynchodercetis sp., Tselfatia sp., Goulmimichthys sp., and scales of Ichtyodectiformes, as well as ammonites and inoceramids (Blanco et al., 2006). The presence of Inoceramus (Mytyloides) labiatus (Maldonado-Koederll, 1956) indicates an Early Turonian age for the sequence. Total carbonate content (CaCO3 = TIC) varies between 62 and 94% in the Limestone beds, which yield Total Organic Carbon (TOC) from 0.4% to 2.5%; the shale intervals contain TIC values consistently lower than 33% and TOC lower than 0.8% Microscopically the limestone beds vary from mudstone to packstone composed essentially of coccoid cyanobacteria similar to coeval deposits in northeastern Mexico, Coahuila State, at Parras de La Fuente (Duque- Botero 2006). Similarly, the microspheroids are spherical to sub-spherical, and occur as isolated elements or aggregates forming series of chains of parallel-packed light lamina 1-2 mm thick. Filamentous cyanobacteria

  13. Numerical simulation of vertical ground-water flux of the Rio Grande from ground-water temperature profiles, central New Mexico

    Science.gov (United States)

    Bartolino, James R.; Niswonger, Richard G.

    1999-01-01

    An important gap in the understanding of the hydrology of the Middle Rio Grande Basin, central New Mexico, is the rate at which water from the Rio Grande recharges the Santa Fe Group aquifer system. Several methodologies-including use of the Glover-Balmer equation, flood pulses, and channel permeameters- have been applied to this problem in the Middle Rio Grande Basin. In the work presented here, ground-water temperature profiles and ground-water levels beneath the Rio Grande were measured and numerically simulated at four sites. The direction and rate of vertical ground-water flux between the river and underlying aquifer was simulated and the effective vertical hydraulic conductivity of the sediments underlying the river was estimated through model calibration. Seven sets of nested piezometers were installed during July and August 1996 at four sites along the Rio Grande in the Albuquerque area, though only four of the piezometer nests were simulated. In downstream order, these four sites are (1) the Bernalillo site, upstream from the New Mexico State Highway 44 bridge in Bernalillo (piezometer nest BRN02); (2) the Corrales site, upstream from the Rio Rancho sewage treatment plant in Rio Rancho (COR01); (3) the Paseo del Norte site, upstream from the Paseo del Norte bridge in Albuquerque (PDN01); and (4) the Rio Bravo site, upstream from the Rio Bravo bridge in Albuquerque (RBR01). All piezometers were completed in the inner-valley alluvium of the Santa Fe Group aquifer system. Ground-water levels and temperatures were measured in the four piezometer nests a total of seven times in the 24-month period from September 1996 through August 1998. The flux between the surface- and ground-water systems at each of the field sites was quantified by one-dimensional numerical simulation of the water and heat exchange in the subsurface using the heat and water transport model VS2DH. Model calibration was aided by the use of PEST, a model-independent computer program that uses

  14. Imaging lithosphere structure and dynamic processes of a world-class metallogenic belt with passive and active seismic methods

    Science.gov (United States)

    Lu, Q.; Gu, Y.; Shi, D.; Yan, J.

    2012-12-01

    The lithosphere structure and deep processes are keys to understanding mineral system and ore-forming processes. Lithosphere-scale process could create big footprints or signatures which can be observed by geophysics methods. SinoProbe-03 has conducted a Transect exploration across middle and lower Yangtze Metallogenic Belt (YMT) in Eastern China. Broadband seismic, reflection seismic, wide-angle reflection and magnetotellurics survey were carried out along the Transect. Seismic reflection profiles and MT survey were also performed in Luzong, Tongling and Ningwu ore districts to construct 3D geological model. The resulting geophysical data provides new information which help to better understanding the lithosphere structure, deep processes and deformation history of the Metallogenic Belt. The major results are: (1) Lower velocity body at the top of upper mantle and a SE dipping high velocity body were imaged by teleseismic tomography beneath YMB; (2) Shear wave splitting results show NE parallel fast-wave polarization direction which parallel with tectonic lineament; (3) The reflection seismic data support the crustal-detachment model, the lower and upper crust was detached during contraction deformation near Tanlu fault and Ningwu volcanic basin; (4) Broadband and reflection seismic confirm the shallow Moho beneath YMB; (5) Strong correlation of lower crust reflectivity with magmatism. All these features suggest that introcontinental subduction, lithosphere delamination, mantle sources magmatic underplating, and MASH process are responsible for the formation of wild-class metallogenic belt. Acknowledgment: We acknowledge the financial support of SinoProbe by the Ministry of Finance and Ministry of Land and Resources, P. R. China, under Grant sinoprobe-03, and financial support by National Natural Science Foundation of China under Grant 40930418

  15. Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B

    Directory of Open Access Journals (Sweden)

    Y. Shinozuka

    2009-05-01

    Full Text Available Remote sensing of cloud condensation nuclei (CCN would help evaluate the indirect effects of tropospheric aerosols on clouds and climate. To assess its feasibility, we examined relationships of submicron aerosol composition to CCN activity and optical properties observed during the MILAGRO/INTEX-B aircraft campaigns. An indicator of CCN activity, κ, was calculated from hygroscopicity measured under saturation. κ for dry 100-nm particles decreased with the organic fraction of non-refractory mass of submicron particles (OMF as 10(−0.43−0.44*OMF over Central Mexico and 10(−0.29−0.70*OMF over the US West Coast. These fits represent the critical dry diameter, centered near 100 nm for 0.2% supersaturation but varied as κ(−1/3, within measurement uncertainty (~20%. The decreasing trends of CCN activity with the organic content, evident also in our direct CCN counts, were consistent with previous ground and laboratory observations of highly organic particles. The wider range of OMF, 0–0.8, for our research areas means that aerosol composition will be more critical for estimation of CCN concentration than at the fixed sites previously studied. Furthermore, the wavelength dependence of extinction was anti-correlated with OMF as −0.70*OMF+2.0 for Central Mexico's urban and industrial pollution air masses, for unclear reasons. The Angstrom exponent of absorption increased with OMF, more rapidly under higher single scattering albedo, as expected for the interplay between soot and colored weak absorbers (some organic species and dust. Because remote sensing products currently use the wavelength dependence of extinction albeit in the column integral form and may potentially include that of absorption, these regional spectral dependencies are expected to facilitate retrievals of aerosol bulk chemistry and CCN activity over Central Mexico.

  16. Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B

    Directory of Open Access Journals (Sweden)

    Y. Shinozuka

    2009-09-01

    Full Text Available Remote sensing of cloud condensation nuclei (CCN would help evaluate the indirect effects of tropospheric aerosols on clouds and climate. To assess its feasibility, we examined relationships of submicron aerosol composition to CCN activity and optical properties observed during the MILAGRO/INTEX-B aircraft campaigns. An indicator of CCN activity, κ, was calculated from hygroscopicity measured under saturation. κ for dry 100 nm particles decreased with increasing organic fraction of non-refractory mass of submicron particles (OMF as 0.34–0.20×OMF over Central Mexico and 0.47–0.43×OMF over the US West Coast. These fits represent the critical dry diameter, centered near 100 nm for 0.2% supersaturation but varied as κ(−1/3, within measurement uncertainty (~20%. The decreasing trends of CCN activity with the organic content, evident also in our direct CCN counts, were consistent with previous ground and laboratory observations of highly organic particles. The wider range of OMF, 0–0.8, for our research areas means that aerosol composition will be more critical for estimation of CCN concentration than at the fixed sites previously studied. Furthermore, the wavelength dependence of extinction was anti-correlated with OMF as −0.70×OMF+2.0 for Central Mexico's urban and industrial pollution air masses, for unclear reasons. The Angstrom exponent of absorption increased with OMF, more rapidly under higher single scattering albedo, as expected for the interplay between soot and colored weak absorbers (some organic species and dust. Because remote sensing products currently use the wavelength dependence of extinction albeit in the column integral form and may potentially include that of absorption, these regional spectral dependencies are expected to facilitate retrievals of aerosol bulk chemical composition and CCN activity over Central Mexico.

  17. Estimated 2008 groundwater potentiometric surface and predevelopment to 2008 water-level change in the Santa Fe Group aquifer system in the Albuquerque area, central New Mexico

    Science.gov (United States)

    Falk, Sarah E.; Bexfield, Laura M.; Anderholm, Scott K.

    2011-01-01

    The water-supply requirements of the Albuquerque metropolitan area of central New Mexico have historically been met almost exclusively by groundwater withdrawal from the Santa Fe Group aquifer system. Previous studies have indicated that the large quantity of groundwater withdrawal relative to recharge has resulted in water-level declines in the aquifer system throughout the metropolitan area. Analysis of the magnitude and pattern of water-level change can help improve understanding of how the groundwater system responds to withdrawals and variations in the management of the water supply and can support water-management agencies' efforts to minimize future water-level declines and improve sustainability. This report, prepared by the U.S. Geological Survey in cooperation with the Albuquerque Bernalillo County Water Utility Authority, presents the estimated groundwater potentiometric surface during winter (from December to March) of the 2008 water year and the estimated changes in water levels between predevelopment and water year 2008 for the production zone of the Santa Fe Group aquifer system in the Albuquerque and surrounding metropolitan and military areas. Hydrographs from selected wells are included to provide details of historical water-level changes. In general, water-level measurements used for this report were measured in small-diameter observation wells screened over short intervals and were considered to best represent the potentiometric head in the production zone-the interval of the aquifer, about 300 feet below land surface to 1,100 feet or more below land surface, in which production wells generally are screened. Water-level measurements were collected by various local and Federal agencies. The 2008 water year potentiometric surface map was created in a geographic information system, and the change in water-level elevation from predevelopment to water year 2008 was calculated. The 2008 water-level contours indicate that the general direction of

  18. The Population Structure of Phytophthora infestans from the Toluca Valley of Central Mexico Suggests Genetic Differentiation Between Populations from Cultivated Potato and Wild Solanum spp.

    Science.gov (United States)

    Flier, Wilbert G; Grünwald, Niklaus J; Kroon, Laurens P N M; Sturbaum, Anne K; van den Bosch, Trudy B M; Garay-Serrano, Edith; Lozoya-Saldaña, Hector; Fry, William E; Turkensteen, Lod J

    2003-04-01

    ABSTRACT The population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected from cultivated potatoes and the native wild Solanum spp., S. demissum and S. xendinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplified fragment length polymorphism (AFLP) multi-locus fingerprint genotype. Isolate samples were monomorphic for mtDNA haplotype because all isolates tested were of the Ia haplotype. A total of 158 multilocus AFLP genotypes were identified among the 170 P. infestans isolates included in this study. P. infestans populations sampled in the Toluca Valley in 1997 were highly variable and almost every single isolate represented a unique genotype based on the analysis of 165 AFLP marker loci. Populations of P. infestans collected from the commercial potato-growing region in the valley, the subsistence potato production area along the slopes of the Nevado de Toluca, and the native Solanum spp. on the forested slopes of the volcano showed a high degree of genetic diversity. The number of polymorphic loci varied from 20.0 to 62.4% for isolates collected from the field station and wild Solanum spp. On average, 81.8% (135) of the AFLP loci were polymorphic. Hetero-zygosity varied between 7.7 and 19.4%. Significant differentiation was found at the population level between strains originating from cultivated potatoes and wild Solanum spp. (P = 0.001 to 0.022). Private alleles were observed in individual isolates collected from all three populations, with numbers of unique dominant alleles varying from 9 to 16 for isolates collected from commercial potato crops and native Solanum spp., respectively. Four AFLP markers were exclusively found present in isolates collected from S. demissum. Indirect estimation of gene flow between populations indicated restricted gene flow between both P. infestans populations from cultivated potatoes and wild Solanum hosts. There was no evidence

  19. Effects of overcast and foggy conditions on transpiration rates of Pinus patula trees along a chronosequence within the cloud belt of the Sierra Madre Oriental, central Veracruz, Mexico

    Science.gov (United States)

    Alvarado-Barrientos, M. S.; Holwerda, F.; Asbjornsen, H.; Sauer, T.; Dawson, T. E.; Bruijnzeel, L. A.

    2010-12-01

    Pinus patula is a native tree species of the montane cloud belt of central Veracruz, Mexico, and one of the most popular species for regional reforestation efforts, both within and outside its natural range of occurrence. Projected regional climate change is likely to cause a rise in the average cloud condensation level by several hundred meters, thereby reducing fog occurrence, whilst overcast conditions are likely to remain similar. To improve our understanding of how water use of P. patula plantations is affected by changes in climatic conditions, we analyzed the response of transpiration rates to fine-scale variations in microclimate, particularly fog immersion and the occurrence of high clouds. We conducted measurements of micrometeorological parameters and transpiration (Et, using the heat ratio sap flow technique) of 15 pine trees representing a range of ages (10-34 years) and sizes (7-60 cm of dbh) during one and a half years (Nov 2008 - May 2010), covering two dry seasons and one wet season. Foggy days were defined using daytime “M-of-N” constructs (at least 4 hours with visibility 1000 m and a maximum incoming solar radiation (Sin) < 700 W m-2. Precipitation and leaf wetness data were used to distinguish between (partly) wet and dry canopy conditions. Daily transpiration rates were normalized for climatic conditions using the FAO reference evaporation ETo to allow determination of the proportional contributions to Et suppression by reductions in Sin and VPD relative to leaf wetness. We found that both foggy and overcast conditions without rainfall produced similar % of Et reduction compared to sunny conditions (60-70%). The strongest Et suppression effects occurred when foggy or overcast conditions were associated with rainfall. However, there was just a slight and non significant difference between the average Et/ETo ratio for foggy days with rainfall (i.e. partially wetted canopy) and fog-only days, suggesting that the suppression of Et was mainly

  20. The water and energy exchange of a shaded coffee plantation in the lower montane cloud forest zone of central Veracruz, Mexico

    Science.gov (United States)

    Holwerda, F.; Bruijnzeel, L. A.; Barradas, V.; Cervantes, J.

    2012-12-01

    The water and energy fluxes of a shaded coffee plantation in the lower montane cloud forest (LMCF) zone of central Veracruz, Mexico, were measured over a two-year period (September 2006-August 2008) using the eddy covariance method. Complementary measurements of throughfall and stemflow were made to study rainfall interception. The sum of the observed sensible (H) and latent (λE) heat fluxes was almost 95% of the net radiation (Rn) minus the canopy heat storage fluxes, indicating very good energy balance closure. Monthly means of the mid-day (11:00-15:00 h) Bowen ratio (H/λE) and evaporative fraction (λE/Rn) averaged 0.74 +/- 0.12 and 0.56 +/- 0.05, respectively. Energy partitioning showed distinct seasonal variation, with significantly higher Bowen ratios prevailing during the dry season (0.81 +/- 0.13) compared to the rainy season (0.67 +/- 0.06). The lower evaporation rates during the dry season reflected a combination of lower soil moisture availability and a lower leaf area of the Inga shade trees during this part of the year. Both the eddy covariance, and the throughfall and stemflow measurements showed average wet-canopy evaporation rate to be very low (0.05 mm/h) compared to the corresponding rainfall rate (3.06 mm/h). As a result, and despite the low canopy storage capacity of the coffee plantation (Cm, 0.50 mm), interception was dominated by post-event evaporation of intercepted water rather than by within-event evaporation. Comparing the results for the coffee plantation with interception data from mature and secondary LMCFs in the study area suggests that the conversion of LMCF to shade-coffee may lead to a decrease in interception loss of 8-18% of incident rainfall. This decrease is caused by a three- to seven-fold decrease in Cm due to the lower leaf area and smaller epiphyte biomass of the coffee plantation. Comparing the eddy covariance-based estimate of dry-canopy evaporation for the coffee plantation with sapflow-based estimates of

  1. Do the historical biogeography and evolutionary history of the digenean Margotrema spp. across central Mexico mirror those of their freshwater fish hosts (Goodeinae?

    Directory of Open Access Journals (Sweden)

    Andrés Martínez-Aquino

    Full Text Available Host-parasite systems provide an ideal platform to study evolution at different levels, including codivergence in a historical biogeography context. In this study we aim to describe biogeographic and codivergent patterns and associated processes of the Goodeinae freshwater fish and their digenean parasite (Margotrema spp. over the last 6.5 Ma (million years, identifying the main factors (host and/or hydrogeomorphology that influenced the evolution of Margotrema. We obtained a species tree for Margotrema spp. using DNA sequence data from mitochondrial and nuclear molecular markers (COI and ITS1, respectively and performed molecular dating to discern divergence events within the genus. The dispersal-extinction-cladogenesis (DEC model was used to describe the historical biogeography of digeneans and applied to cophylogenetic analyses of Margotrema and their goodeine hosts. Our results showed that the evolutionary history of Margotrema has been shaped in close association with its geographic context, especially with the geological history of central Mexico during the Pleistocene. Host-specificity has been established at three levels of historical association: a Species-Species, represented by Xenotaenia resolanae-M. resolanae exclusively found in the Cuzalapa River Basin; b Species-Lineage, represented by Characodon audax-M. bravoae Lineage II, exclusive to the Upper and Middle Mezquital River Basin, and c Tribe-Lineage, including two instances of historical associations among parasites and hosts at the taxonomical level of tribe, one represented by Ilyodontini-M. bravoae Lineage I (distributed across the Ayuquila and Balsas River Basins, and another comprised of Girardinichthyini/Chapalichthyini-M. bravoae Lineage III, found only in the Lerma River Basin. We show that the evolutionary history of the parasites is, on several occasions, in agreement with the phylogenetic and biogeographic history of their hosts. A series of biogeographic and host

  2. Do the historical biogeography and evolutionary history of the digenean Margotrema spp. across central Mexico mirror those of their freshwater fish hosts (Goodeinae)?

    Science.gov (United States)

    Martínez-Aquino, Andrés; Ceccarelli, Fadia Sara; Eguiarte, Luis E; Vázquez-Domínguez, Ella; de León, Gerardo Pérez-Ponce

    2014-01-01

    Host-parasite systems provide an ideal platform to study evolution at different levels, including codivergence in a historical biogeography context. In this study we aim to describe biogeographic and codivergent patterns and associated processes of the Goodeinae freshwater fish and their digenean parasite (Margotrema spp.) over the last 6.5 Ma (million years), identifying the main factors (host and/or hydrogeomorphology) that influenced the evolution of Margotrema. We obtained a species tree for Margotrema spp. using DNA sequence data from mitochondrial and nuclear molecular markers (COI and ITS1, respectively) and performed molecular dating to discern divergence events within the genus. The dispersal-extinction-cladogenesis (DEC) model was used to describe the historical biogeography of digeneans and applied to cophylogenetic analyses of Margotrema and their goodeine hosts. Our results showed that the evolutionary history of Margotrema has been shaped in close association with its geographic context, especially with the geological history of central Mexico during the Pleistocene. Host-specificity has been established at three levels of historical association: a) Species-Species, represented by Xenotaenia resolanae-M. resolanae exclusively found in the Cuzalapa River Basin; b) Species-Lineage, represented by Characodon audax-M. bravoae Lineage II, exclusive to the Upper and Middle Mezquital River Basin, and c) Tribe-Lineage, including two instances of historical associations among parasites and hosts at the taxonomical level of tribe, one represented by Ilyodontini-M. bravoae Lineage I (distributed across the Ayuquila and Balsas River Basins), and another comprised of Girardinichthyini/Chapalichthyini-M. bravoae Lineage III, found only in the Lerma River Basin. We show that the evolutionary history of the parasites is, on several occasions, in agreement with the phylogenetic and biogeographic history of their hosts. A series of biogeographic and host

  3. CENSUS AND STATISTICAL CHARACTERIZATION OF SOIL AND WATER QUALITY AT ABANDONED AND OTHER CENTRALIZED AND COMMERCIAL DRILLING-FLUID DISPOSAL SITES IN LOUISIANA, NEW MEXICO, OKLAHOMA, AND TEXAS

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. Dutton; H. Seay Nance

    2003-06-01

    Commercial and centralized drilling-fluid disposal (CCDD) sites receive a portion of spent drilling fluids for disposal from oil and gas exploration and production (E&P) operations. Many older and some abandoned sites may have operated under less stringent regulations than are currently enforced. This study provides a census, compilation, and summary of information on active, inactive, and abandoned CCDD sites in Louisiana, New Mexico, Oklahoma, and Texas, intended as a basis for supporting State-funded assessment and remediation of abandoned sites. Closure of abandoned CCDD sites is within the jurisdiction of State regulatory agencies. Sources of data used in this study on abandoned CCDD sites mainly are permit files at State regulatory agencies. Active and inactive sites were included because data on abandoned sites are sparse. Onsite reserve pits at individual wells for disposal of spent drilling fluid are not part of this study. Of 287 CCDD sites in the four States for which we compiled data, 34 had been abandoned whereas 54 were active and 199 were inactive as of January 2002. Most were disposal-pit facilities; five percent were land treatment facilities. A typical disposal-pit facility has fewer than 3 disposal pits or cells, which have a median size of approximately 2 acres each. Data from well-documented sites may be used to predict some conditions at abandoned sites; older abandoned sites might have outlier concentrations for some metal and organic constituents. Groundwater at a significant number of sites had an average chloride concentration that exceeded nonactionable secondary drinking water standard of 250 mg/L, or a total dissolved solids content of >10,000 mg/L, the limiting definition for underground sources of drinking water source, or both. Background data were lacking, however, so we did not determine whether these concentrations in groundwater reflected site operations. Site remediation has not been found necessary to date for most abandoned

  4. Potential postwildfire debris-flow hazards: a prewildfire evaluation for the Sandia and Manzano Mountains and surrounding areas, central New Mexico

    Science.gov (United States)

    Tillery, Anne C.; Haas, Jessica R.; Miller, Lara W.; Scott, Joe H.; Thompson, Matthew P.

    2014-01-01

    Wildfire can drastically increase the probability of debris flows, a potentially hazardous and destructive form of mass wasting, in landscapes that have otherwise been stable throughout recent history. Although there is no way to know the exact location, extent, and severity of wildfire, or the subsequent rainfall intensity and duration before it happens, probabilities of fire and debris-flow occurrence for different locations can be estimated with geospatial analysis and modeling efforts. The purpose of this report is to provide information on which watersheds might constitute the most serious, potential, debris-flow hazards in the event of a large-scale wildfire and subsequent rainfall in the Sandia and Manzano Mountains. Potential probabilities and estimated volumes of postwildfire debris flows in the unburned Sandia and Manzano Mountains and surrounding areas were estimated using empirical debris-flow models developed by the U.S. Geological Survey in combination with fire behavior and burn probability models developed by the U.S. Department of Agriculture Forest Service. The locations of the greatest debris-flow hazards correlate with the areas of steepest slopes and simulated crown-fire behavior. The four subbasins with the highest computed debris-flow probabilities (greater than 98 percent) were all in the Manzano Mountains, two flowing east and two flowing west. Volumes in sixteen subbasins were greater than 50,000 square meters and most of these were in the central Manzanos and the western facing slopes of the Sandias. Five subbasins on the west-facing slopes of the Sandia Mountains, four of which have downstream reaches that lead into the outskirts of the City of Albuquerque, are among subbasins in the 98th percentile of integrated relative debris-flow hazard rankings. The bulk of the remaining subbasins in the 98th percentile of integrated relative debris-flow hazard rankings are located along the highest and steepest slopes of the Manzano Mountains. One

  5. Reviews and new metallogenic models of mineral deposits in South China: An introduction

    Science.gov (United States)

    Hu, Rui-Zhong; Chen, Wei Terry; Xu, De-Ru; Zhou, Mei-Fu

    2017-04-01

    In South China, the Yangtze and Cathaysia blocks were welded together along the Jiangnan Fold Belt during Neoproterozoic time (∼830 Ma). Large-scale mineralization in these two blocks occurred from Proterozoic to Cenozoic, making the region one of the most important polymetallic metallogenic provinces in the world. Of particular importance are world-class deposits of iron-oxide copper gold (IOCG), sediment-hosted Mn-P-Al-(Ni, Mo, PGE), syenite-carbonatite-related REE, felsic intrusion-related Sn-W-Mo-Cu-Fe-Pb-Zn, mafic intrusion-related V-Ti-Fe and Cu-Ni-PGE and low-temperature hydrothermal Pb, Zn, Au, and Sb (Fig. 1). In addition, the Ta-Nb, Hg, As, Tl and U deposits in South China are among the world largest of these kinds. Because of these deposits, South China has been a focus of researches for many years. Publications before 2005 were mostly restricted in Chinese. In the past decade, some case studies on some world-class deposits in South China are available in international journals. These recent studies have advanced our understanding of their mode of formation. However, some important issues regarding the timing, tectonic setting and mechanisms of metal concentration still remain poorly understood. This special issue brings together some of the latest information on these topics, including major review papers on specific types of mineralization and several papers dealing with some specific deposits in the region. We anticipate that this issue will generate more interests in the studies of mineral deposits in South China. In this introduction, we outline the tectonic framework and associated deposits.

  6. Potential field studies of the central San Luis Basin and San Juan Mountains, Colorado and New Mexico, and southern and western Afghanistan

    Science.gov (United States)

    Drenth, Benjamin John

    This dissertation includes three separate chapters, each demonstrating the interpretive utility of potential field (gravity and magnetic) geophysical datasets at various scales and in various geologic environments. The locations of these studies are the central San Luis Basin of Colorado and New Mexico, the San Juan Mountains of southwestern Colorado, and southern and western Afghanistan. The San Luis Basin is the northernmost of the major basins that make up the Rio Grande rift, and interpretation of gravity and aeromagnetic data reveals patterns of rifting, rift-sediment thicknesses, distribution of pre-rift volcanic and sedimentary rocks, and distribution of syn-rift volcanic rocks. Syn-rift Santa Fe Group sediments have a maximum thickness of ˜2 km in the Sanchez graben near the eastern margin of the basin along the central Sangre de Cristo fault zone. Under the Costilla Plains, thickness of these sediments is estimated to reach ˜1.3 km. The Santa Fe Group sediments also reach a thickness of nearly 1 km within the Monte Vista graben near the western basin margin along the San Juan Mountains. A narrow, north-south-trending structural high beneath San Pedro Mesa separates the graben from the structural depression beneath the Costilla Plains. Aeromagnetic anomalies are interpreted to mainly reflect variations of remanent magnetic polarity and burial depth of the 5.3-3.7 Ma Servilleta basalt of the Taos Plateau volcanic field. Magnetic-source depth estimates indicate patterns of subsidence following eruption of the basalt and show that the Sanchez graben has been the site of maximum subsidence. One of the largest and most pronounced gravity lows in North America lies over the rugged San Juan Mountains in southwestern Colorado. A buried, low-density silicic batholith related to an Oligocene volcanic field coincident with the San Juan Mountains has been the accepted interpretation of the source of the gravity low since the 1970s. However, this interpretation was

  7. 1985 Mexico City, Mexico Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The magnitude 8.1 earthquake occurred off the Pacific coast of Mexico. The damage was concentrated in a 25 square km area of Mexico City, 350 km from the epicenter....

  8. El género Hydrophilus (Coleoptera: Hydrophilidae: Hydrophilina en México y Centroamérica The genus Hydrophilus (Coleoptera: Hydrophilidae: Hydrophilina in Mexico and Central America

    Directory of Open Access Journals (Sweden)

    Roberto Arce-Pérez

    2013-03-01

    Full Text Available A partir de la revisión morfológica de 499 ejemplares adultos y datos bibliográficos se actualizó la identidad y la distribución precisa de las especies del género Hydrophilus Geoffroy, 1762 que habitan en México y Centroamérica. Se presenta a H. (Dibolocelus purpuracens Régimbart, 1901 como nuevo registro para México. Las especies más ampliamente distribuidas son H. (H. ensifer Brullé, 1837 en 5 países y las Antillas e H. (H. insularis Castelnau, 1840 en 4 países y las Antillas. Los países con mayor riqueza fueron México con 5 especies, y Nicaragua y Costa Rica con 3 especies. En México el estado con mayor riqueza es Veracruz, y en Nicaragua los departamentos de León y Río San Juan. Se presenta una clave ilustrada para el reconocimiento de las especies.The taxonomy and precise distribution of the species of the genus Hydrophilus Geoffroy, 1762 from Mexico and Central America are reviewed, based on the morphological study of499 adult specimens, descriptions and literature records. Hydrophilus (Dibolocelus purpuracens Régimbart, 1901 is recorded for the first time for Mexico. Species with widest distribution are H. (H. ensifer Brullé, 1837 cited from 5 countries and in the Antilles, and H. (H. insularis Castelnau, 1840 cited from 4 countries and the Antilles. The richest countries are Mexico with 5 species, and Costa Rica and Nicaragua with 3 species. The highest species richness is recorded for the state of Veracruz, Mexico, and from the departments of León and Río San Juan, Nicaragua. An illustrated key to the species is included.

  9. On the behavior of site effects in Central Mexico (the Mexican Volcanic Belt – MVB, based on records of shallow earthquakes that occurred in the zone between 1998 and 2011

    Directory of Open Access Journals (Sweden)

    A. Clemente-Chavez

    2013-11-01

    Full Text Available The Mexican Volcanic Belt (MVB is a seismogenic zone that transects the central part of Mexico with an east–west orientation. The risk and hazard seismic of this seismogenic zone has not been studied at detail due to the scarcity of instrumental data as well as because seismicity in the continental regimen of Central Mexico is not too frequent, however, it is known that there are precedents of large earthquakes (Mw > 6.0 that have taken place in this zone. The Valley of Mexico City (VM is the sole zone, within the MVB, which has been studied in detail; mainly focusing on the ground amplification during large events such as the 1985 subduction earthquake that occurred in Michoacan. The purpose of this article is to analyze the behavior of site effects in the MVB zone based on records of shallow earthquakes (data not reported before that occurred in the zone between 1998 and 2011. We present a general overview of site effects on the MVB, a classification of the stations in order to reduce the uncertainty in the data to obtain attenuation parameters in future works, and some comparisons between the information presented here and that presented in previous studies. A regional evaluation of site effects and Fourier Acceleration Spectrum (FAS shape was estimated based on 80 records of 22 shallow earthquakes within the MVB zone. Data of 25 stations were analyzed. Site effects were estimated by using the Horizontal-to-Vertical Spectral Ratio (HVSR methodology. The results show that seismic waves are less amplified in the northeast sites of the MVB with respect to the rest of the zone and that it is possible to classify two groups of stations: (1 stations with Negligible Site Amplification (NSA and (2 stations with Significant Site Amplification (SSA. Most of the sites in the first group showed small ( These aspects help to advance the understanding about the amplification behavior and of the expected seismic risk on the Central Mexico due to large

  10. On the behavior of site effects in central Mexico (the Mexican volcanic belt - MVB), based on records of shallow earthquakes that occurred in the zone between 1998 and 2011

    Science.gov (United States)

    Clemente-Chavez, A.; Zúñiga, F. R.; Lermo, J.; Figueroa-Soto, A.; Valdés, C.; Montiel, M.; Chavez, O.; Arroyo, M.

    2014-06-01

    The Mexican volcanic belt (MVB) is a seismogenic zone that transects the central part of Mexico with an east-west orientation. The seismic risk and hazard of this seismogenic zone has not been studied in detail due to the scarcity of instrumental data as well as because seismicity in the continental regime of central Mexico is not too frequent. However, it is known that there are precedents of large earthquakes (Mw > 6.0) that have taken place in this zone. The valley of Mexico City (VM) is the sole zone, within the MVB, that has been studied in detail. Studies have mainly focused on the ground amplification during large events such as the 1985 subduction earthquake that occurred off coast of Michoacán. The purpose of this article is to analyze the behavior of site effects in the MVB zone based on records of shallow earthquakes (data not reported before) that occurred in the zone between 1998 and 2011. We present a general overview of site effects in the MVB, a classification of the stations in order to reduce the uncertainty in the data when obtaining attenuation parameters in future works, as well as some comparisons between the information presented here and that presented in previous studies. A regional evaluation of site effects and Fourier acceleration spectrum (FAS) shape was estimated based on 80 records of 22 shallow earthquakes within the MVB zone. Data of 25 stations were analyzed. Site effects were estimated by using the horizontal-to-vertical spectral ratio (HVSR) methodology. The results show that seismic waves are less amplified in the northeast sites of the MVB with respect to the rest of the zone and that it is possible to classify two groups of stations: (1) stations with negligible site amplification (NSA) and (2) stations with significant site amplification (SSA). Most of the sites in the first group showed small (<3) amplifications while the second group showed amplifications ranging from 4 to 6.5 at frequencies of about 0.35, 0.75, 15 and 23

  11. Deep-seated structure and metallogenic dynamics of the Ailaoshan polymetallic mineralization concentration area, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Ailaoshan poly-metallic mineralization concentrated area (MCA) consists of the well known Ailaoshan metallogenic belt and adjacent mineral districts and/or deposits. Located in an area of several complex and intersecting tectonic units, the Ailaoshan poly-metallic MCA is controlled by deep crustal and mantle tectonism. Through interpretation of remote sensing images, we identified a large ring structure system that surrounds the MCA. This ring structure encloses regional deep-crustal faults, ductile shear zones, geothermal anomalies, magmatic rocks, and the major mineral deposits, all of which are the reflections of deep tectonic geodynamics that have been long active in this area. Geophysical data indicate that the crust is comprised of relatively stable two or three layers, with some irregular lower-velocity belts. The Moho in the ring sutures occurs as an area of local uplift. There exists an obvious transitional zone between the crust and mantle boundaries. Asthenopheric mantle shows multi-layer upwelling, which indicates multiple events during different geological epochs. It is believed that these mantle events or pulses were responsible for the formation of the regional shear zones, magmatic rocks, and polymetallic orebodies. Furthermore, an integrated metallogenic dynamics model related to the asthenopheric upwelling pulses in the MCA is established, defining events as old as Late Paleozoic.

  12. Deep-seated structure and metallogenic dynamics of the Ailaoshan polymetallic mineralization concentration area, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    GE LiangSheng; DENG Jun; GUO XiaoDong; ZOU YiLin; LIU YinChun

    2009-01-01

    The Ailaoshan poly-metalllc mineralization concentrated area (MCA) consists of the well known Aileoshan metallogenic belt and adjacent mineral districts and/or deposits. Located in an area of sev-eral complex and intersecting tectonic units, the Ailaoshan poly-metallic MCA is controlled by deep crustal and mantle tectonism. Through interpretation of remote sensing images, we identified a large ring structure system that surrounds the MCA. This ring structure encloses regional deep-crustal faults, ductile shear zones, geothermal anomalies, magmatic rocks, and the major mineral deposits, all of which are the reflections of deep tectonic geodynamics that have been long active in this area. Geo-physical data indicate that the crust is comprised of relatively stable two or three layers, with some irregular lower-velocity belts. The Moho in the ring sutures occurs as an area of local uplift. There ex-lets an obvious transitional zone between the crust and mantle boundaries. Asthenopheric mantle shows multi-layer upwelling, which indicates multiple events during different geological epochs. It is believed that these mantle events or pulses were responsible for the formation of the regional shear zones, magmatic rocks, and polymetallic orebodies. Furthermore, an integrated metallogenic dynamics model related to the asthenopheric upwelling pulses in the MCA is established, defining events as old as Late Paleozoic.

  13. Realignment of Cannon Air Force Base Curry County, New Mexico

    Science.gov (United States)

    1990-05-01

    the northern border of New Mexico to the Gila, lower Rio Grande, middle Pecos, and Canadian valleys. It is seen occasionally in summer and as a...marten is present in the north central part of New Mexico in the San Juan and Sangre de Cristo mountains. Loss or alteration of habitat and exploitation...Idaho, and these birds migrate southward to winter in the central Rio Grande Valley in New Mexico. The New Mexico population has increased to a

  14. Origin and evolution of ore-forming fluids in the Hemushan magnetite-apatite deposit, Anhui Province, Eastern China, and their metallogenic significance

    Science.gov (United States)

    Luo, Gan; Zhang, Zhiyu; Du, Yangsong; Pang, Zhenshan; Zhang, Yanwen; Jiang, Yongwei

    2015-12-01

    The Middle-Lower Yangtze River Metallogenic Belt in the northern Yangtze Block is one of the most important economic mineral districts in China. The Hemushan deposit is a medium-class Fe deposit located in the southern part of the Ningwu iron ore district of the Middle-Lower Yangtze River Metallogenic Belt. The Fe-orebodies are mainly hosted in the contact zone between diorite and Triassic marble. The actinolite-phlogopite-apatite-magnetite ore shows metasomatic/filling textures and disseminated/mesh-vein structures. Based on evidences and petrographic observations, the ore-forming process can be divided into three distinct periods-the early metallogenic period (albite-diopside stage), the middle metallogenic period (magnetite stage and hematite stage), and the late metallogenic period (quartz-pyrite stage and carbonate stage). Fluid inclusion studies show four types of inclusions: type I daughter mineral-bearing three-phase inclusions (L + V + S), type II vapor-rich two-phase inclusions (L + V), type III liquid-rich two phase inclusions (L + V), and minor type IV liquid-phase inclusions (L). Apatites from the magnetite stage contain type I, type II and type III inclusions; anhydrites from the hematite stage mainly contain abundant type II inclusions and relatively less type I inclusions; quartz and calcite from the late metallogenic stage are mainly characterized by type III inclusions. Laser Raman spectroscopy and microthermometry of fluid inclusions show that the ore-forming fluids broadly correspond to unsaturated NaCl-H2O system. From the magnetite stage to the carbonate stage, the ore-forming fluids evolved from moderate-high temperature (average 414 °C), moderate salinity (average 25.01 wt.% NaCl equiv.) conditions to low temperature (average 168 °C), low salinity (average 6.18 wt.% NaCl equiv.) conditions. Hydrogen and oxygen isotopic studies indicate that the ore-forming fluid during the early stage of middle metallogenic period was mainly of magmatic

  15. Estimated 2012 groundwater potentiometric surface and drawdown from predevelopment to 2012 in the Santa Fe Group aquifer system in the Albuquerque metropolitan area, central New Mexico

    Science.gov (United States)

    Powell, Rachel I.; McKean, Sarah E.

    2014-01-01

    Historically, the water-supply requirements of the Albuquerque metropolitan area of central New Mexico were met almost exclusively by groundwater withdrawal from the Santa Fe Group aquifer system. In response to water-level declines, the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) began diverting water from the San Juan-Chama Drinking Water Project in December 2008 to reduce the use of groundwater to meet municipal demand. Modifications in the demand for water and the source of the supply of water for the Albuquerque metropolitan area have resulted in a variable response in the potentiometric surface of the production zone (the interval of the aquifer, from within about 200 feet below the water table to 900 feet or more, in which supply wells generally are screened) of the Santa Fe Group aquifer system. Analysis of the magnitude and spatial distribution of water-level change can help improve the understanding of how the groundwater system responds to withdrawals and variations in the management of the water supply and can support water-management agencies’ efforts to minimize future water-level declines and improve sustainability. The U.S. Geological Survey (USGS), in cooperation with the ABCWUA, has developed an estimate of the 2012 potentiometric surface of the production zone of the Santa Fe Group aquifer system in the Albuquerque metropolitan area. This potentiometric surface is the latest in a series of reports depicting the potentiometric surface of the area. This report presents the estimated potentiometric surface during winter (from December to March) of water year 2012 and the estimated changes in potentiometric surface between predevelopment (pre-1961) and water year 2012 for the production zone of the Santa Fe Group aquifer system in the Albuquerque metropolitan area. Hydrographs from selected piezometers are included to provide details of historical water-level changes. In general, water-level measurements used for this report were

  16. Postwildfire debris-flow hazard assessment of the area burned by the 2012 Little Bear Fire, south-central New Mexico

    Science.gov (United States)

    Tillery, Anne C.; Matherne, Anne Marie

    2013-01-01

    A preliminary hazard assessment was developed of the debris-flow potential from 56 drainage basins burned by the Little Bear Fire in south-central New Mexico in June 2012. The Little Bear Fire burned approximately 179 square kilometers (km2) (44,330 acres), including about 143 km2 (35,300 acres) of National Forest System lands of the Lincoln National Forest. Within the Lincoln National Forest, about 72 km2 (17,664 acres) of the White Mountain Wilderness were burned. The burn area also included about 34 km2 (8,500 acres) of private lands. Burn severity was high or moderate on 53 percent of the burn area. The area burned is at risk of substantial postwildfire erosion, such as that caused by debris flows and flash floods. A postwildfire debris-flow hazard assessment of the area burned by the Little Bear Fire was performed by the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture Forest Service, Lincoln National Forest. A set of two empirical hazard-assessment models developed by using data from recently burned drainage basins throughout the intermountain Western United States was used to estimate the probability of debris-flow occurrence and volume of debris flows along the burn area drainage network and for selected drainage basins within the burn area. The models incorporate measures of areal burn extent and severity, topography, soils, and storm rainfall intensity to estimate the probability and volume of debris flows following the fire. Relative hazard rankings of postwildfire debris flows were produced by summing the estimated probability and volume ranking to illustrate those areas with the highest potential occurrence of debris flows with the largest volumes. The probability that a drainage basin could produce debris flows and the volume of a possible debris flow at the basin outlet were estimated for three design storms: (1) a 2-year-recurrence, 30-minute-duration rainfall of 27 millimeters (mm) (a 50 percent chance of occurrence in

  17. Photosynthetic discrimination drives seasonal variations in the δ13C value of soil-respired CO2 in mixed C3-C4 ecosystems from central New Mexico

    Science.gov (United States)

    Breecker, D. O.; Sharp, Z. D.; McFadden, L. D.; Litvak, M. E.

    2009-12-01

    Understanding the processes responsible for variations in the carbon isotope composition of soil-respired CO2 (δ13Cr) is important in studies of ecophysiology, decomposition, pedogenesis and ecosystem to global scale CO2 isotope mass balances. In this paper, we discuss explanations for large seasonal variations in δ13Cr values observed in soils from the Sevilleta National Wildlife Refuge, central New Mexico. One soil from each of the following four biomes was studied: Plains Grassland, Piñon-Juniper Woodland, Great Basin Shrubland (GBS) and Chihuahuan Desert Shrubland (CDS). Soil organic matter (SOM) content is higher in the woodland soil (1.2% by mass) than in the grassland and shrubland soils, which have low concentrations of SOM (0.05-0.4%). The vegetation in each soil is a mixture of C3 and C4 plants, although Larrea tridentata (C3) constitutes > 90% of vegetative cover at the CDS site. Soil gas samples were collected monthly between September 2006 and May 2008 from belowground (5-100 cm depth) and were analyzed for the concentration and carbon isotope composition of soil pore space CO2. These measurements were used to calculate the average depth of CO2 production (zavg) and δ13Cr in each soil. This approach is useful for studying seasonal variations of respiration at depth in soils as opposed to surface CO2 flux measurements which are better suited for short timescale, transient state, shallow respiration studies. Winter/summer δ13Cr values (‰ vs. VPDB) were -23.5/-16.5, -24.1/-20.4, -26.9/-19.5, -29.5/-21.6 for the grassland, woodland, GBS and CDS, respectively. Values of zavg varied between 20 cm and > 2 m and were unrelated to δ13Cr (r2 2 m during the winter and dry part of the summer, respectively. Taken together, five observations suggest that photosynthetic discrimination rather than other processes is primarily responsible for the large seasonal variation in δ13Cr values: 1) δ13Cr values correlate well with vapor pressure deficit, which is

  18. Magmatic Conduit Metallogenic System in Jinchuan Cu-Ni (PGE) Sulfide Deposit

    Science.gov (United States)

    Su, S.; Tang, Z.; Zhou, M.; Song, C.

    2014-12-01

    The Jinchuan Cu-Ni (PGE) sulfide deposit is located in the southwestern margin of North China Craton. Jinchuan ultramafic intrusion hosts the third largest magmatic Cu-Ni deposit in the world. There are mainly four orebodies, namely, orebody-58, orebody-24, orebody-1, and orebody-2, respectively from west to east in the deposit. The primary characteristics of Jinchuan Cu-Ni sulfide deposit are the following: (1) There is an obvious boundary between orebodys and country rocks, usually orebodys intruded into country rocks. (2) "sulfide melts" migrate and settle in the later stage of magma evolution. (3) Fluid Minerals Assemblages are found in the sulfide ores, there is Phl+Cc+Pn+Ccp+Po in orebody-2; Phl+Dol+AP+Pn+Ccp+Po in orebody-24; Q+Mag+AP+Pn+Ccp+Po in orebody-58. (4) Massive sulfides mainly occur in orebody-2, and its PGE content is very rare. Pt-Pd enrichment zones mainly occur in orebody-1; orebody-24 and orebody-58. Ir vs. Ru, Rh, Pt, Pd show positive relationship in orebody-2, but Ir vs. Ru, Rh show positive relationship, Ir vs. Pt, Pd exhibit negative relationship in orebody-1, orebody-24 and orebody-58. The modeling of Ir-Pd shows that the massive sulfide in orebody-2 maybe the origin of MSS. Pt-Pd enrichment zones in orebody-1 orebody-24 and orebody-58 are the relic liquid of monosulfide solid solution segregation; (5) Cu/Ni value is 1.24 in orebody-58, 1.56 in orebody-24, 1.83 in orebody-1, and 2.06 in orebody-2. These features imply that (1) "ore magma" or "melt-fluid bearing metal" formed in the staging chamber in depth; (2) "ore magma" might contain a lot of fluids; (3) "melt-fluid bearing metal" flow moves as a whole; (4) The moving direction of melt-fluid bearing metal flow is form west to east. The ores are enriched in Ni in the front, and enriched in Cu, Pt, Pd in the back of Jinchuan Magmatic Conduit Metallogenic System.

  19. Geochemistry of magnetite from Proterozoic Fe-Cu deposits in the Kangdian metallogenic province, SW China

    Science.gov (United States)

    Chen, Wei Terry; Zhou, Mei-Fu; Gao, Jian-Feng; Hu, Ruizhong

    2015-10-01

    Fe-Cu deposits in the Kangdian Fe-Cu metallogenic province, SW China, are hosted in Paleoproterozoic meta-volcanic-sedimentary sequences and are spatially associated with coeval mafic intrusions. Several well-known examples are the giant Lala, Dahongshan, and Yinachang deposits. They have a common paragenetic sequence of an early Fe-oxide stage associated with sodic alteration and a late Cu-sulfide stage associated with potassic-carbonate alteration. Magnetite dominates the Fe-oxide stage of these deposits but is also present in the Cu-sulfide stage of the Lala deposit. This study uses trace element compositions of magnetite to examine the nature and origin of the ore-forming fluids. The magnetite has variable concentrations of Ti, Al, Mg, Mn, Si, V, Cr, Ca, Co, Ni, Sc, Zn, Cu, Mo, Sn, and Ga, which are thought to have been controlled mainly by fluid compositions and/or intensive parameters (e.g., temperature and oxygen fugacity ( fO2)). Fluid-rock interaction and coprecipitating mineral phases appear to be less important in controlling the magnetite compositions. Magnetite grains in the Fe-oxide stage of the Lala and Dahongshan deposits have comparable trace element compositions and were likely precipitated from chemically similar fluids. High Ni contents of magnetite in both deposits, coupled with previous isotopic data and the fact that the two deposits are spatially associated with coeval mafic intrusions, strongly suggest that the ore-forming fluids were genetically related to the mafic magmas that formed the intrusions. Magnetite grains in the Fe-oxide stage of the Yinachang deposit have much lower V and Ni but higher Sn and Mo contents than those of the Lala and Dahongshan deposits and are thus thought to have precipitated from more oxidized and Mo-Sn-rich fluids that may have evolved from relatively felsic magmas. Magnetite grains from the Cu-sulfide and Fe-oxide stages of the Lala deposit are broadly similar in composition, but those in the Cu

  20. Conformation of an evaluation process for a license renovation solicitude of a nuclear power plant in Mexico; Conformacion de un proceso de evaluacion para una solicitud de renovacion de licencia de una central nuclear en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Serrano R, M. L., E-mail: mlserrano@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

    2012-10-15

    So that the construction stages, of operation, closing, dismantlement and the radioactive waste disposal of a nuclear power plant (NPP) are carried out in Mexico, is necessary that the operator has a license, permission or authorization for each stage. In Mexico, these licenses, permissions or authorizations are granted by the Energy Secretariat with base in the verdict of the Comision Nacional de Seguridad Nuclear y Salvaguardias (CNSNS). The operation licenses ar the moment effective for the reactors of the Nuclear Power Plant of Laguna Verde (NPP-L V) they will expire respectively in the year 2020 and 2025 for the Unit 1 and Unit 2, for what the CNSNS has begun its preparation before a potential solicitude of the licensee to continue the operation of the NPP-L V. Defining the process to continue and to generate the documents that would help in this phase as normalization, guides, procedures, regulations, controls, etc., is the task that intends to be carried out the regulator body so that the evaluation process is effective and efficient, so much for the same regulator body as for the licensee. This work exposes the advance that the CNSNS has in this aspect and is centered specifically in the conformation of an evaluation process of license renovation solicitude, taking as base what the regulator body of the United States of North America (US NRC) established and following to the IAEA. Also, this work includes statistical of electric power production in Mexico, licensing antecedents for the NPP-L V, a world perspective of the license renovations and the regulation of the US NRC related to the license renovation of a NPP. (Author)

  1. Regulator process for the authorization of an amendment to the operation license of a nuclear power plant in Mexico; Proceso regulador para la autorizacion de una enmienda a la licencia de operacion de una central nuclear en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Perez, R.; Espinosa V, J.M.; Salgado, J.R.; Mamani, Y.R. [CNSNS, Dr. Barragan 779, Col. Narvarte, 03020 Mexico D.F. (Mexico)

    2005-07-01

    The regulator process by which an authorization is granted from an amendment to the License of Operation of a nuclear power station in Mexico is described. It makes an appointment the effective legal mark, the technical characteristics of the modification, the evaluation process and deposition upon oath of tests and finally the elaboration of the Safety report and the Technical Verdict that is a correspondent for the regulator organism to the Secretary of Energy, the one that in turn is the responsible of granting the amendment the License just as it establishes it the Law. (Author)

  2. Used battery collection camping in central Mexico: statics and metal content report, advances in recycling technology and legislative/regulatory situation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Guevara-Garcia, J. A.; Montiel-Corona, V.; Juarez Galindo, A.; Mendoza Sarmiento, G.; Munoz Lopez, F.; Papalotzi Juarez, S.; Cruz Diaz, R. de la

    2009-07-01

    Nowadays, environmental pollution produced by the disposal of used cells and batteries is a major concern in Mexico. The regulatory law proposal (NMX-AA-104-SCFI-2006) establish a content limit 20, 7.5 and 5 fold higher in Hg, Cd and Pb, respectively, than the European directive 2006/66/CE. Furthermore, transnational companies refused to have participation on the collection/recycling process, putting forward that pollution comes only from illegal market batteries. (Author)

  3. Crutal and upper mantle structure beneath the mid-lower Yangtze metallogenic belt revealed by passive-source seismic array

    Science.gov (United States)

    Shi, D.; Lu, Q.; Yan, J.; Xu, W.; Zhang, G.; Jiang, G.; Dong, S.

    2010-12-01

    The mid-lower reach of Yangtze River is an important metallogenic belt in Eastern China. To understand the formation and geodynamic process for the mineral deposits, SinoProbe program carries out a multidisciplinary trans-section in this region, including active-source methods such as near-vertical (NV) and wide-angle reflection(WA) seismic reflections, passive-source methods such as broadband seismic array(BB) and magnetotellurics (MT), and geochemical and geological observations. The broadband seismic array was initiated in November, 2009, which was deployed in a linear profile, and will record for ~ 1 year. Other geophysical components are planed to be initiated in 2011. The BB array is composed of 52 stations with a much denser spatial interval of ~5 km, starts from Liyang in Jiangsu province in the southeast, across the Yangtze metallogenic belt and the Tanlu fault and then ends in the North China Block (NCB) in the northwest. Based upon the data available at present, preliminary teleseismic receiver function cross-sections have been achieved. The preliminary results show a clear variation of Moho depths along the profile, which, we believe, shed lights on the gloomy and complicated geodynamic process. The Moho is seen around 30 km deep along the profile, becoming moderately shallow to ~27 km beneath the Yangtze metallogenic belt, getting gradually deeper across the Tanlu fault and reaching to a depth of ~32 km beneath the north end of profile in the NCB. In addition to the Moho structure, we have observed some intra-crustal converters and significant scattering energy from the Tanlu fault on the receiver function profile. More methods have been applying to the BB dataset. More detailed descriptions of the field experiment and coming results from this passive-source experiment will be presented. ACKNOWLEDGMENTS We acknowledge the financial support of SinoProbe by the Ministry of Finance and Ministry of Land and Resources, P. R. China, under Grant sinoprobe-03

  4. Radiological surveillance in Mexico, derived of the accident of the Fukushima Daiichi nuclear power plant; Vigilancia radiologica en Mexico, derivado del accidente en la central nuclear de Fukushima Daiichi

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre G, J.; Nohpal J, X., E-mail: jaguirre@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias, Departamento de Vigilancia Radiologica, Dr. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

    2012-10-15

    March 11, 2011 an earthquake of 9.0 grades in the Richter scale, originated in the coast of Tohoku, Japan, in the Pacific Ocean gave origin to a tsunami that caused an accident in the Fukushima Daiichi nuclear power plant. Due to this accident, derived of the loss of the reactor cooling system, as well as of the prolonged absence of alternating and direct current, radiological protection actions were realized without being able to avoid the liberation of radioactive material to the atmosphere and ocean. The radiological impact of these liberations, not only in Japan but around the world, mainly in the north hemisphere of the Earth, was analyzed by means of environmental dose measurements and radionuclide concentrations in soil and water, among others. In the Mexico case, air samples data were obtained, as well as environmental dose celerity and full-length counts of the people coming from Japan near the disaster area. The present work contains the obtained results of the realized measurements in Mexico, same that have been used to make a summary and analysis of the dispersion in the environment in several countries of the world. (Author)

  5. Helminth parasites of atherinopsid freshwater fishes (Osteichthyes: Atheriniformes from central Mexico Helmintos parásitos de aterinópsidos de agua dulce (Osteichthyes: Atheriniformes del centro de México

    Directory of Open Access Journals (Sweden)

    Georgina Lira-Guerrero

    2008-12-01

    Full Text Available Between May 1997 and September 1998, 270 atherinopsids belonging to 7 fish species were analyzed for helminths in 6 lakes located in central Mexico. In addition, a database with all the available previous records of helminth parasites of atherinopsids was built. Based on both information sources, we analyze the composition of the helminth fauna parasitizing atherinopsid freshwater fishes from central Mexico, in order to determine some general species compositional patterns. The helminth fauna parasitizing this fish family in central Mexico is composed by 10 digeneans, 13 cestodes, 1 acanthocephalan, and 8 nematodes (24 of them as larval stage. Individual species richness ranged from 1 to 22 helminth species. Feeding habits of the hosts are identified as the main factor in determining helminth species composition (22 of them are acquired through ingestion. Helminth species composition of almost all host species was dominated by generalist helminth species. Only 2 specialist species were found: Allocreadium mexicanum and Spinitectus osorioi, representing the core helminth fauna of this group of fishes. These results corroborate the hypothesis that the parasite fauna in freshwater fishes is largely circumscribed by higher levels of monophyletic host taxa.Entre mayo de 1997 y septiembre de 1998, se recolectaron 270 aterinópsidos pertenecientes a 7 especies de peces en busca de helmintos, en 6 lagos del centro de México. Basados en esta información y en los registros previos sobre helmintos en este grupo de hospederos, se construyó una base de datos. El objetivo de este estudio es analizar dicha información, para establecer algunos patrones generales acerca de la composición de los helmintos que los parasitan. Treinta y dos especies de helmintos infectan a los peces de esta familia (10 digéneos, 13 cestodos, 1 acantocefalo y 8 nematodos, 24 de ellas en estado larvario. Los hábitos alimenticios de los aterinópsidos determinan la composici

  6. Another Mexico

    Science.gov (United States)

    Romano, Carlin

    2009-01-01

    A Mexican saying holds that "Como Mexico no hay dos"--There is only one Mexico. American media these days interpret that notion with a vengeance. Story after story depicts a country overrun by out-of-control drug wars and murder, where corrupt police officers trip over beheaded victims more often than they nab perpetrators. South of the…

  7. La geopolítica de México en Centro América: ¿una hegemonía regional? Mexico's geopolitics in Central America: regional hegemony?

    Directory of Open Access Journals (Sweden)

    Alberto Rocha

    2006-12-01

    analizar el Mecanismo de Diálogo y Concertación de Tuxtla-Gutiérrez y sus tres ámbitos de operación: 1. El ámbito político. 2. El ámbito del desarrollo. 3. El ámbito de la cooperación técnica regional. 4. El ámbito económico, comercial y financiero.Mexico as well as Brazil (first decade of 2000 started to release geo-economic and geo-political projections about their unmediated surroundings (their region of belonging and their mediated surroundings (their neighboring region, besides playing major political roles in their far surroundings (the Latin American and Caribbean region and their remote surroundings (the American continent. As a result, we have proposed and developed the idea that such situations and realities are those of processes of constitution of States with "sub-hegemonic" roles, with their respective functions of "sub-hegemony". We therefore ask the following question: Why are both Mexico and Brazil defining "sub-hegemonic" roles? Are such roles and functions possible within a continental space where a "superpower" exerts unquestionable "supremacy" besides seeking to redefine its "hegemony" (the one now undergoing a crisis? In order to work on the theme of Mexico's geopolitical relations with Central America, we have carried out four approximations: Mexico's current stance; historical background of the relations; process of institutionalization of cooperation; and field of action of the relations. Besides, the work is concluded with some ideas about Mexico's geopolitical view. The approximation to Mexico's structural stance in the world and in the American Continent seeks to highlight realities in its condition of semiperipheral and "sub-hegemonic" country. The historical approximation leads to the 1980s and the 1990s, when the background for Mexico's cooperation with Central America is established and that cooperation is started and strengthened. The institutional approximation, focused on the 1990s and the early 2000s, approaches the field of

  8. Resource Assessment of the In-Place and Potentially Recoverable Deep Natural Gas Resource of the Onshore Interior Salt Basins, North Central and Northeastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini

    2006-09-30

    The objectives of the study were: (1) to perform resource assessment of the thermogenic gas resources in deeply buried (>15,000 ft) natural gas reservoirs of the onshore interior salt basins of the north central and northeastern Gulf of Mexico areas through petroleum system identification, characterization and modeling; and (2) to use the petroleum system based resource assessment to estimate the volume of the deep thermogenic gas resource that is available for potential recovery and to identify those areas in the interior salt basins with high potential for this thermogenic gas resource. Petroleum source rock analysis and petroleum system characterization and modeling, including thermal maturation and hydrocarbon expulsion modeling, have shown that the Upper Jurassic Smackover Formation served as the regional petroleum source rock in the North Louisiana Salt Basin, Mississippi Interior Salt Basin, Manila Subbasin and Conecuh Subbasin. Thus, the estimates of the total hydrocarbons, oil, and gas generated and expelled are based on the assumption that the Smackover Formation is the main petroleum source rock in these basins and subbasins. The estimate of the total hydrocarbons generated for the North Louisiana Salt Basin in this study using a petroleum system approach compares favorably with the total volume of hydrocarbons generated published by Zimmermann (1999). In this study, the estimate is 2,870 billion barrels of total hydrocarbons generated using the method of Schmoker (1994), and the estimate is 2,640 billion barrels of total hydrocarbons generated using the Platte River software application. The estimate of Zimmermann (1999) is 2,000 to 2,500 billion barrels of total hydrocarbons generated. The estimate of gas generated for this basin is 6,400 TCF using the Platte River software application, and 12,800 TCF using the method of Schmoker (1994). Barnaby (2006) estimated that the total gas volume generated for this basin ranges from 4,000 to 8,000 TCF. Seventy

  9. Students and Teachers' Reasons for Using the First Language within the Foreign Language Classroom (French and English) in Central Mexico (Razones de alumnos y maestros sobre el uso de la primera lengua en el salón de lenguas extranjeras (francés e inglés) en el centro de México)

    Science.gov (United States)

    Mora Pablo, Irasema; Lengeling, M. Martha; Rubio Zenil, Buenaventura; Crawford, Troy; Goodwin, Douglas

    2011-01-01

    The present study explores the use of the first language in a context of foreign language teaching. This qualitative research presents the classroom practice and points of view of French and English teachers and students within a public educational institute in central Mexico using the techniques of questionnaires and semi-structured interviews.…

  10. TPH and PAH concentrations in the subsoil of polyduct segments, oil pipeline pumping stations, and right-of-way pipelines from Central Mexico

    Science.gov (United States)

    Iturbe, Rosario; Castro, Alejandrina; Perez, Guillermina; Flores, Carlos; Torres, Luis G.

    2008-10-01

    For the year 1996, 366 incidents related with clandestine poaching of oil-products were reported in Mexico, 159 in 1997, and 240 in 1998. For the year 2003 (the most recently reported figure), there were 136 events. Petroleos Mexicanos (PEMEX), very concerned with the environmental agenda, has developed programs oriented to diminish contamination levels in all of its oil facilities. This work was aimed at characterizing zones around polyduct segments, pipelines, pumping stations, and right-of-way pipelines located in the center of Mexico. The TPH contaminated sites were, in decreasing order, polyduct km 39 + 150 > polyduct km 25 + 020 > Zoquital > Tepetitlan > Catalina > Venta Prieta > Ceiba. Most of the sampled points showed the presence of more than one of the 16 PAHs considered by USEPA as priority pollutants. Except point TEPE 2A, where no PAHs were detected, all the sampled points showed values from low to medium concentrations; however, values found at the sites did not exceed the limits according to the Mexican or the American legislation. The place with the largest contaminated area corresponded to the polyduct km 39 + 150, with 130 m2 and 260 m3 to be treated. The least contaminated area was that around the JUAN 4 point at Juandho station, with 20 m2 and 22 m3 of contaminated soil. The total area to be treated is about 230 m2 and 497 m3.

  11. Caracterización de Tagetes filifolia del centro-sur de México por morfometría de los aquenios Characterization of Tagetes filifolia from central-south Mexico by morphometric achene traits

    Directory of Open Access Journals (Sweden)

    Carlos A. Núñez-Colín

    2011-06-01

    Full Text Available Tagetes filifolia Lag. es una especie ruderal ampliamente distribuida en México de la cual se empieza a conocer su variabilidad morfológica, como parte de una serie de estudios relacionados con su posible domesticación para obtener biopesticidas. Para ampliar el conocimiento sobre este recurso vegetal se definieron mediante 11 características del aquenio 104 recolecciones del centro-sur de México empleando una técnica digital de imágenes. Se identificaron 5 diferentes grupos morfológicos. El Grupo I presentó recolecciones con aquenios pequeños y anchos; el Grupo II, aquenios grandes y anchos; el Grupo III, aquenios pequeños y alargados; el Grupo IV, aquenios grandes y alargados, y el Grupo V, aquenios grandes pero más alargados que los del Grupo IV. Las variables más discriminantes fueron el índice de alargamiento, índice de compactación, índice de redondez, relación eje menor/ eje mayor para la raíz canónica 1, y perímetro longitudinal y longitud del eje mayor para la raíz canónica 2. La gran variabilidad de las características de la forma y tamaño de los aquenios de T. filifolia se pudo agrupar en 5 morfotipos, los cuales no estuvieron presentes en toda la región centro-sur de México.Tagetes filifolia Lag. is a ruderal species widely distributed in Mexico from which is starting to make knowledge about its morphological variability as a part of a study sequence related with its possible domestication to obtain biopesticides. For acquiring more knowledge on this plant resource, 104 accessions from central-south Mexico were morphologically characterized by 11 achene traits employing a digital images technique. Five different morphologic groups were identified. Group I had accessions with small and wide achenes, group II had big and wide achenes, group III had small and long achenes, group IV had big and long achenes, and group V had big achenes but longer than group IV. The most discriminant variables were elongation

  12. Anthropogenic changes and environmental degradation in pre-Hispanic and post-Colonial periods: soil erosion modelled with WEPP during Late Holocene in Teotihuacán Valley (central Mexico)

    Science.gov (United States)

    Lourdes González-Arqueros, M.; Mendoza Cantú, Manuel E.

    2015-04-01

    Land use changes and support practices are a worldwide significant issue in soil erosion and subsequently, land degradation. Anthropogenic changes, along different periods of the history in the last 2000 years in the Valley of Teotihuacan (central Mexico), highlight that soil erosion varies depending on how the management and the intensity of soil use is handled, considering the soils as a main resource. As a part of a broader effort to reconstruct the erosion dynamics in the Teotihuacán Valley through geoarchaeological approaches, this study apply a process-based watershed hydrology and upland erosion model, Water Erosion Prediction Project (WEPP). This research aims to contribute with insights through modelling and to recreate soil erosion and sedimentation dynamics in several historical periods with different environmental and anthropogenic scenarios. The Geo-spatial interface for WEPP (GeoWEPP) was used to characterize location of detachment, depositions and erosion predicted on the profile through time, based on current and hypothetical reconstructed conditions in the watershed. Climate, topography, soil and land use were used as inputs for the WEPP model to estimate runoff fluxes, soil loss rates, and sediment delivery ratio (SDR) for three historical scenarios: current period, reconstructed Teotihuacán period (AD 1-650), and reconstructed Aztec period (AD 1325-1520). Over a simulated and stablished timeframe for those social periods, the runoff, soil loss rate and SDR were estimated to be greater during the Aztec period. We assume that in general the climate conditions for this period were wetter, compared with present, in agreement with several authors that proposed climate reconstructions for the center of Mexico. It is also highlighted that support practices were more effective in this period. The next period with higher values is the current one, and fewer rates are estimated for the Teotihuacán period. This comparison release new arguments in the

  13. Geological and geochemical character and genesis of the Jinlongshan-Qiuling gold deposits in Qinling orogen: Metallogenic mechanism of the Qinling-pattern Carlin-type gold deposits

    Institute of Scientific and Technical Information of China (English)

    张复新,陈衍景,李超Department; of; Geology,; Peking; University,; Beijing; 100871,; China; ,张静Department; of; Geology,; Peking; University,; Beijing; 100871,; China; ,马建秦,李欣Department; of; Geology,; Peking; University,; Beijing; 100871,; China

    2000-01-01

    The Qinling Carlin-type gold deposit belt is the second largest Carlin-type gold ore concentrated area in the world and occurs in Mesozoic intracontinental collisional orogen, contrasting to the Carlin-type gold deposits in the Basin and Range province in Cenozoic active continental margin of West America. With ore-forming ages focussed at the range of 197.45-129.45 Ma, its metallogenic geodynamic background was the decornpression-pyrogenation regime at the transition stage from collisional compression to extension, indicating that gold mineralization synchronized with the Mesozoic continental collision. Geochemical studies discover that ore fluids and materials mainly came from the Hercynian-lndosinian tectonic layer. Mesozoic intracontinental subduction of Hercynian-lndosinian association along the Shuanghe-Gongguan fault led to the formation of Jinlongshan-Qiuling gold deposits. Accordingly, the tectonic metallogenic model is established for Qinling-pattern Carlin-type gold deposits.

  14. Appendix C: Summary of Major Metallogenic Belts in Northeast Asia (the Russian Far East, Yakutia, Siberia, Transbaikalia, Northern China, Mongolia, South Korea, and Japan)

    Science.gov (United States)

    Rodionov, Sergey M.; Obolenskiy, Alexander A.; Distanov, Elimir G.; Badarch, Gombosuren; Dejidmaa, Gunchin; Hwang, Duk-Hwan; Khanchuk, Alexander I.; Ogasawara, Masatsugu; Nokleberg, Warren J.; Parfenov, Leonid M.; Prokopiev, Andrei V.; Seminskiy, Zhan V.; Smelov, Alexander P.; Yan, Hongquan; Davydov, Yuriy V.V.; Fridovskiy, Valeriy Yu.; Gamyanin, Gennandiy N.; Gerel, Ochir; Kostin, Alexei V.; Letunov, Sergey A.; Li, Xujun; Nikitin, Valeriy M.; Ratkin, Vladimir V.; Shpikerman, Vladimir I.; Sudo, Sadahisa; Sotnikov, Vitaly I.; Spiridonov, Alexander V.; Stepanov, Vitaly A.; Sun, Fengyue; Sun, Jiapeng; Sun, Weizhi; Supletsov, Valeriy M.; Timofeev, Vladimir F.; Tyan, Oleg A.; Vetluzhskikh, Valeriy G.; Wakita, Koji; Yakovlev, Yakov V.; Zorina, Lydia M.

    2010-01-01

    The major purposes of this chapter are to provide (1) an overview of the regional geology, tectonics, and metallogenesis of Northeast Asia for readers who are unfamiliar with the region, (2) a general scientific introduction to the succeeding chapters of this volume, and (3) an overview of the methodology of metallogenic and tectonic analysis used in this study. We also describe how a high-quality metallogenic and tectonic analysis, including construction of an associated metallogenic-tectonic model will greatly benefit other mineral resource studies, including synthesis of mineral-deposit models; improve prediction of undiscovered mineral deposit as part of a quantitative mineral-resource-assessment studies; assist land-use and mineral-exploration planning; improve interpretations of the origins of host rocks, mineral deposits, and metallogenic belts, and suggest new research. Research on the metallogenesis and tectonics of such major regions as Northeast Asia (eastern Russia, Mongolia, northern China, South Korea, and Japan) and the Circum-North Pacific (the Russian Far East, Alaska, and the Canadian Cordillera) requires a complex methodology including (1) definitions of key terms, (2) compilation of a regional geologic base map that can be interpreted according to modern tectonic concepts and definitions, (3) compilation of a mineral-deposit database that enables a determination of mineral-deposit models and clarification of the relations of deposits to host rocks and tectonic origins, (4) synthesis of a series of mineral-deposit models that characterize the known mineral deposits and inferred undiscovered deposits in the region, (5) compilation of a series of metallogenic-belt belts constructed on the regional geologic base map, and (6) construction of a unified metallogenic and tectonic model. The summary of regional geology and metallogenesis presented here is based on publications of the major international collaborative studies of the metallogenesis and

  15. Mexico North-South Deflections (DMEX97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for Mexico, and North-Central is the DMEX97 model. The computation used about one million terrestrial and marine...

  16. Mexico East-West Deflections (DMEX97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' surface deflection of the vertical grid for Mexico, and North-Central is the DMEX97 model. The computation used about one million terrestrial and marine...

  17. Demand of natural uranium to satisfy the requirements of nuclear fuel of new nuclear power plants in Mexico; Demanda de uranio natural para satisfacer los requerimientos de combustible nuclear de nuevas centrales nucleares en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Rios, M. del C.; Alonso, G.; Palacios H, J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: jrrs@nuclear.inin.mx

    2008-07-01

    Due to the expectation of that in Mexico new plants of nuclear energy could be installed, turns out from the interest to evaluate the uranium requirements to operate those plants and to also evaluate if the existing reserves in the country could be sufficient to satisfy that demand. Three different scenes from nuclear power plant expansion for the country are postulated here that are desirable for the diversification of generation technologies. The first scene considers a growth in the generation by nuclear means of two reactors of type ABWR that could enter operation by years 2015 and 2020, in the second considers the installation of four reactors but as of 2015 and new every 5 years, in the scene of high growth considers the installation of 6 reactors of the same type that in the other scenes, settling one every three years as of 2015. The results indicate that the uranium reserves could be sufficient to only maintain in operation to one of the reactors proposed by the time of their useful life. (Author)

  18. Consideraciones e importancia social en torno al cultivo del frijol en el centro de México Considerations and social importance of the bean crop in central Mexico

    Directory of Open Access Journals (Sweden)

    Dora Ma. Sangerman-Jarquín

    Full Text Available En México, el grano de frijol por su alto contenido de proteína es básico para la alimentación de su población; ocupa el segundo lugar en importancia nacional después del maíz. La producción de las leguminosas, principalmente el frijol ha disminuido una tasa de 3.2%, con respecto a un crecimiento de población más rápido que la producción. El frijol es una leguminosa que constituye una fuente de proteínas e hidratos de carbono natural; además es abundante en vitamina B como: niacina, ácido fólico y tianina; también proporciona hierro, cobre, zinc, fósforo, potasio, magnesio y calcio, contiene un alto contenido de fibra. Existen múltiples variedades de frijol que se caracterizan por su tamaño, color, forma y tipo de crecimiento. Se considera que en total existen 70 especies; en México estás ascienden a 50, destacan cinco especies que se han domesticado Phaseolus vulgaris L. (frijol común, Phaseolus coccineus L. (frijol ayocote, Phaseolus lunatus L. (frijol comba, Phaseolus dumosus (frijol gordo y Phaseolus acutifolius Gray (frijol tepari. En México se cultivan cerca de 70 variedades, de acuerdo a la norma son: negros, pintos, bayos, amarillos y rosados. El cultivo del frijol presenta características propias y definidas en el marco de la soberanía alimentaria, en virtud de que representa un alimento principal para la población rural y urbana. El programa de mejoramiento genético de frijol del Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP del Campo Experimental Valle de México (CEVAMEX, ha contribuido en gran medida en generar la tecnología necesaria para que el país alcance la autosuficiencia alimentaria sostenida en este cultivo. Esta tecnología incluye la liberación de variedades con mayor capacidad de rendimiento y mejor calidad alimentaria y culinaria.In Mexico, common bean is an essential component in the diet of the population due to its high protein content; it ranks second

  19. Molecular detection and sensitivity to antibiotics and bacteriocins of pathogens isolated from bovine mastitis in family dairy herds of central Mexico.

    Science.gov (United States)

    León-Galván, Ma Fabiola; Barboza-Corona, José E; Lechuga-Arana, A Arianna; Valencia-Posadas, Mauricio; Aguayo, Daniel D; Cedillo-Pelaez, Carlos; Martínez-Ortega, Erika A; Gutierrez-Chavez, Abner J

    2015-01-01

    Thirty-two farms (n = 535 cows) located in the state of Guanajuato, Mexico, were sampled. Pathogens from bovine subclinical mastitis (SCM) and clinical mastitis (CLM) were identified by 16S rDNA and the sensitivity to both antibiotics and bacteriocins of Bacillus thuringiensis was tested. Forty-six milk samples were selected for their positive California Mastitis Test (CMT) (≥3) and any abnormality in the udder or milk. The frequency of SCM and CLM was 39.1% and 9.3%, respectively. Averages for test day milk yield (MY), lactation number (LN), herd size (HS), and number of days in milk (DM) were 20.6 kg, 2.8 lactations, 16.7 animals, and 164.1 days, respectively. MY was dependent on dairy herd (DH), LN, HS, and DM (P antibiotics tested in this study.

  20. Paleomagnetic Evidence From Volcanic Units of Valsequillo Basin for the Laschamp Geomagnetic Excursion, and Implications for Early Human Occupation in Central Mexico

    Science.gov (United States)

    Rocha, J.; Gogichaishvili, A.; Martin Del Pozzo, A.; Urrutia-Fucugauchi, J.; Soler, A. M.

    2007-12-01

    Alleged human and animal footprints were found within the upper bedding surfaces of the Xalnene volcanic ash layer that outcrops in Valsequillo basin, south of Puebla, Mexico (Gonzalez et al., Quaternary Science Reviews doi: 10.1016/j.quascirev, 2005). The ash has been dated to 40 ka by means of optically stimulated luminescence analysis. This was held as new evidence that America was colonized earlier. We carried out paleomagnetic and rock magnetic analysis of 18 Xalnene ash block and core samples collected at two distinct localities, and nineteen standard paleomagnetic cores belonging to nearby monogenetic volcanoes. Our data yield evidence that both volcanic lava flow and Xalnene ash were emplaced at during the Laschamp geomagnetic event spanning from about 45 to 39 ka. This interpretation indicates that Valsequillo probably remains one of the sites of early human occupation in the Americas, producing evidence of early arrival.

  1. Paleomagnetic and rock-magnetic study on volcanic units of the Valsequillo Basin: implications for early human occupation in central Mexico

    Science.gov (United States)

    Goguitchaichvili, Avto; Pozzo, Ana Lillian Martin-Del; Rocha-Fernandez, Jose Luis; Urrutia-Fucugauchi, Jaime; Soler-Arechalde, Ana Maria

    2009-01-01

    Alleged human and animal footprints were found within the upper bedding surfaces of the Xalnene volcanic ash layer that outcrops in the Valsequillo Basin, south of Puebla, Mexico (Gonzalez et al, 2005). The ash has been dated at 40 ka by optically stimulated luminescence analysis, thereby providing new evidence that America was colonized earlier than the Clovis culture (about 13.5 Ma). We carried out paleomagnetic and rock magnetic analysis on 18 Xalnene ash block and core samples collected at two distinct localities and 19 standard paleomagnetic cores belonging to nearby monogenetic volcanoes. Our data provide evidence that both the volcanic lava flow and Xalnene ash were emplaced during the Laschamp geomagnetic event spanning from about 45 to 39 ka.

  2. The effects of land use change on carbon content in the aerial biomass of an Abies religiosa (Kunth Schltdl. et Cham. forest in central Veracruz, Mexico

    Directory of Open Access Journals (Sweden)

    M.R. Pineda Lopez

    2013-04-01

    Full Text Available Aim of study. Were analyzed patterns and dynamics of forest cover change and land use for the period 1995-2005, and estimated carbon content in biomass in a forest of fir (Abies religiosa.Area of study. Ejido El Conejo in the Cofre de Perote National Park, Veracruz, Mexico.Material and Methods. Spatial data (maps, orthophotographs were used: (UTM; GRS 80 spheroid; zone 14, datum ITRF92; units: metres. Maps for 1995 and 2005 were constructed and compared. Carbon content in the aboveground biomass of fir (Abies religiosa was estimated using an equation specific to species.Main results. After one decade, the forested area had increased slightly (0.25%. The main type of land cover change was from shrubland to forest (probability of change 0.41; the change from forestland to shrubland with trees was 0.05%, and from forest to agriculture was 0.02%. Data from 2008 confirmed that the A. religiosa forest located in the ejido is distributed in largely unconnected fragments, of which some have a high density of young trees. Estimated carbon content in the aboveground biomass (163.51 Mg ha-1 was higher than that estimated for other forests of the same species in Mexico.Research highlights. It is recommended that ecological corridors be established throughout the reforested area, in order to connect these fragments (and increase carbon sequestration and favour faunal and floral conservation. Finally, recognition should be given to the high vulnerability of A. religiosa forests to climate change, given their high degree of fragmentation and critical altitudinal limit.Key words: Aboveground biomass; carbon storage; ecological corridors; fir forest.

  3. The effects of land use change on carbon content in the aerial biomass of an Abies religiosa (Kunth Schltdl. et Cham.) forest in central Veracruz, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Pineda-Lopez, M. R.; Sanchez-Velasquez, L. R.; Vazquez-Dominguez, G.; Rojo-Alboreca, A.

    2013-05-01

    Aim of study.) Were analyzed patterns and dynamics of forest cover change and land use for the period 1995-2005, and estimated carbon content in biomass in a forest of fir (Abies religiosa). Area of study. Ejido El Conejo in the Cofre de Perote National Park, Veracruz, Mexico. Material and Methods. Spatial data (maps, ortho photographs) were used: (UTM); GRS 80 spheroid; zone 14, datum ITRF92; units: metres. Maps for 1995 and 2005 were constructed and compared. Carbon content in the aboveground biomass of fir (Abies religiosa) was estimated using an equation specific to species. Main results. After one decade, the forested area had increased slightly (0.25%). The main type of land cover change was from shrubland to forest (probability of change 0.41); the change from forestland to shrubland with trees was 0.05%, and from forest to agriculture was 0.02%. Data from 2008 confirmed that the A. religiosa forest located in the ejido is distributed in largely unconnected fragments, of which some have a high density of young trees. Estimated carbon content in the aboveground biomass (163.51 Mg ha-1) was higher than that estimated for other forests of the same species in Mexico. Research highlights. It is recommended that ecological corridors be established throughout the reforested area, in order to connect these fragments (and increase carbon sequestration) and favour faunal and floral conservation. Finally, recognition should be given to the high vulnerability of A. religiosa forests to climate change, given their high degree of fragmentation and critical altitudinal limit. (Author) 55 refs.

  4. 基于MORPAS多元信息成矿预测研究--以上黑龙江成矿带为例%Multi-informational MORPAS Gold Metallogenic Prediction-Taking Upper Heilongj iang Metallogenic Belt as Example

    Institute of Scientific and Technical Information of China (English)

    杨吉波; 员俊杰; 周殿宇; 李师白

    2014-01-01

    Uppert Heilongjiang metallogenic belt is mainly composed of the early-Middle Jurassic coal bearing clastic rock in River-Lake-pluvial facies.At present,a number of small and medium-sized deposits have been found,so it is great significance for metallogenic prediction in the area.In this article,multi-source data sets including geological,geophysical,geochemical elsdatawer eintegr ated for mineral poten-tial mapping by using MORPAS technology. Furthermore these deposit recognition criteria layers were combined in the weight of evidence model,which used the spatial correlations between the evidence layers and the known mineral occurrences,to calculate the posterior probability and indentify the delineated pro-spective area.%上黑龙江成矿带主要由早中侏罗世河流湖泊洪积相含煤碎屑岩组成,目前已发现多个中小型矿床,在该区进行成矿预测意义重大。利用 MORPAS成矿预测系统,采用证据权重法进行成矿预测工作,在充分研究区内已知矿床的成矿规律基础上,以1∶25万比例的地质图为背景,物化探异常分析子系统对1∶20万区域化探数据进行C-A分形确定异常下限,综合现有的找矿标志,提取有利的成矿要素,进行针对处理,制成上黑龙江成矿带 MORPAS金成矿预测分析图,提供成矿靶区,为森林高覆盖区提供找矿有利条件。

  5. Molecular Detection and Sensitivity to Antibiotics and Bacteriocins of Pathogens Isolated from Bovine Mastitis in Family Dairy Herds of Central Mexico

    Science.gov (United States)

    León-Galván, Ma. Fabiola; Barboza-Corona, José E.; Lechuga-Arana, A. Arianna; Valencia-Posadas, Mauricio; Aguayo, Daniel D.; Cedillo-Pelaez, Carlos; Martínez-Ortega, Erika A.; Gutierrez-Chavez, Abner J.

    2015-01-01

    Thirty-two farms (n = 535 cows) located in the state of Guanajuato, Mexico, were sampled. Pathogens from bovine subclinical mastitis (SCM) and clinical mastitis (CLM) were identified by 16S rDNA and the sensitivity to both antibiotics and bacteriocins of Bacillus thuringiensis was tested. Forty-six milk samples were selected for their positive California Mastitis Test (CMT) (≥3) and any abnormality in the udder or milk. The frequency of SCM and CLM was 39.1% and 9.3%, respectively. Averages for test day milk yield (MY), lactation number (LN), herd size (HS), and number of days in milk (DM) were 20.6 kg, 2.8 lactations, 16.7 animals, and 164.1 days, respectively. MY was dependent on dairy herd (DH), LN, HS, and DM (P < 0.01), and correlations between udder quarters from the CMT were around 0.49 (P < 0.01). Coagulase-negative staphylococci were mainly identified, as well as Staphylococcus aureus, Streptococcus uberis, Brevibacterium stationis, B. conglomeratum, and Staphylococcus agnetis. Bacterial isolates were resistant to penicillin, clindamycin, ampicillin, and cefotaxime. Bacteriocins synthesized by Bacillus thuringiensis inhibited the growth of multiantibiotic resistance bacteria such as S. agnetis, S. equorum, Streptococcus uberis, Brevibacterium stationis, and Brachybacterium conglomeratum, but they were not active against S. sciuri, a microorganism that showed an 84% resistance to antibiotics tested in this study. PMID:25815326

  6. Value of Riparian Vegetation Remnants for Leaf-Litter Ants (Hymenoptera: Formicidae) in a Human-Dominated Landscape in Central Veracruz, Mexico.

    Science.gov (United States)

    García-Martínez, Miguel Á; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela; Valenzuela-González, Jorge E

    2015-12-01

    Riparian remnants are linear strips of vegetation immediately adjacent to rivers that may act as refuges for biodiversity, depending on their habitat quality. In this study, we evaluated the role of riparian remnants in contributing to the diversity of leaf-litter ants by determining the relationship between ant diversity and several riparian habitat characteristics within a human-dominated landscape in Veracruz, Mexico. Sampling was carried out in 2012 during both dry and rainy seasons at 12 transects 100 m in length, where 10 leaf-litter samples were collected along each transect and processed with Berlese-Tullgren funnels and Winkler sacks. A total of 8,684 individuals belonging to 53 species, 22 genera, and seven subfamilies were collected. The observed mean alpha diversity accounted for 34.4% of the total species recorded and beta diversity for 65.6%. Species richness and composition were significantly related to litter-layer depth and soil compaction, which could limit the distribution of ant species depending on their nesting, feeding, and foraging habits. Riparian remnants can contribute toward the conservation of ant assemblages and likely other invertebrate communities that are threatened by anthropogenic pressures. In human-dominated landscapes where remnants of riparian vegetation give refuge to a diverse array of myrmecofauna, the protection of the few remaining and well-preserved riparian sites is essential for the long-term maintenance of biodiversity.

  7. Molecular Detection and Sensitivity to Antibiotics and Bacteriocins of Pathogens Isolated from Bovine Mastitis in Family Dairy Herds of Central Mexico

    Directory of Open Access Journals (Sweden)

    Ma. Fabiola León-Galván

    2015-01-01

    Full Text Available Thirty-two farms (n=535 cows located in the state of Guanajuato, Mexico, were sampled. Pathogens from bovine subclinical mastitis (SCM and clinical mastitis (CLM were identified by 16S rDNA and the sensitivity to both antibiotics and bacteriocins of Bacillus thuringiensis was tested. Forty-six milk samples were selected for their positive California Mastitis Test (CMT (≥3 and any abnormality in the udder or milk. The frequency of SCM and CLM was 39.1% and 9.3%, respectively. Averages for test day milk yield (MY, lactation number (LN, herd size (HS, and number of days in milk (DM were 20.6 kg, 2.8 lactations, 16.7 animals, and 164.1 days, respectively. MY was dependent on dairy herd (DH, LN, HS, and DM P<0.01, and correlations between udder quarters from the CMT were around 0.49 P<0.01. Coagulase-negative staphylococci were mainly identified, as well as Staphylococcus aureus, Streptococcus uberis, Brevibacterium stationis, B. conglomeratum, and Staphylococcus agnetis. Bacterial isolates were resistant to penicillin, clindamycin, ampicillin, and cefotaxime. Bacteriocins synthesized by Bacillus thuringiensis inhibited the growth of multiantibiotic resistance bacteria such as S. agnetis, S. equorum, Streptococcus uberis, Brevibacterium stationis, and Brachybacterium conglomeratum, but they were not active against S. sciuri, a microorganism that showed an 84% resistance to antibiotics tested in this study.

  8. Evolution of the 2014-2015 sea surface temperature warming in the central west coast of Baja California, Mexico, recorded by remote sensing

    Science.gov (United States)

    Robinson, Carlos J.

    2016-07-01

    Extraordinarily warm sea surface temperatures were present in the California Current System during 2014-2015. In several locations surface waters temperature registered new record high in the recent time series. This study focuses in the evolution of the warming in the southern part of the California Current System (CCS), off the west coast of Baja California, Mexico. Analysis of monthly sea surface temperature (SST), sea level pressure, and wind speed as measured by satellite from January 1988 to December 2015 show that recent warming occurred during two distinct periods. From May 2014 to April 2015, SST warming was related to weak coastal winds not associated to El Niño. During this period occurred the longest sustained record of 15 months of negative wind anomalies in the series. A reduction of wind stress suggests a weakened coastal upwelling, and consequently, cold water not transported into the surface. The second process of warming occurred from September to December 2015, during a strong El Niño condition.

  9. EXECUTIVE SUMMARY OF STATE DATA RELATED TO ABANDONED CENTRALIZED AND COMMERCIAL DRILLING-FLUID DISPOSAL SITES IN LOUISIANA, NEW MEXICO, OKLAHOMA, AND TEXAS

    Energy Technology Data Exchange (ETDEWEB)

    H. Seay Nance

    2003-03-01

    This 2003 Spring Semi-Annual Report contains a summary of the Final Technical Report being prepared for the Soil Remediation Requirements at Commercial and Centralized Drilling-Fluid Disposal (CCDD) Sites project funded by the United States Department of Energy under DOE Award No. DE-AC26-99BC15225. The summary describes (1) the objectives of the investigation, (2) a rationale and methodology of the investigation, (3) sources of data, assessment of data quality, and data availability, (4) examples of well documented centralized and commercial drilling-fluid disposal (CCDD) sites and other sites where drilling fluid was disposed of, and (5) examples of abandoned sites and measures undertaken for their assessment and remediation. The report also includes most of the figures, tables, and appendices that will be included in the final report.

  10. From Back-arc Drifting to Arc Accretion: the Late Jurassic-Early Cretaceous Evolution of the Guerrero Terrane Recorded by a Major Provenance Change in Sandstones from the Sierra de los Cuarzos, Central Mexico

    Science.gov (United States)

    Palacios Garcia, N. B.; Martini, M.

    2014-12-01

    The Guerrero terrane composed of Middle Jurassic-Early Cretaceous arc assemblages, were drifted from the North American continental mainland during lower Early Cretaceous spreading in the Arperos back arc basin, and subsequently accreted back to the continental margin in the late Aptian. Although the accretion of the Guerrero terrane represents one of the major tectonic processes that shaped the southern North American Pacific margin, the stratigraphic record related to such a regional event was not yet recognized in central Mexico. Due to the Sierra de los Cuarzos is located just 50 km east of the Guerrero terrane suture belt, its stratigraphic record should be highly sensitive to first order tectonic changes and would record a syn-tectonic deposits related to this major event. In that study area, were identified two main Upper Jurassic-Lower Cretaceous clastic units. The Sierra de los Cuarzos formation represents the lowermost exposed stratigraphic record. Sedimentary structures, sandstones composition, and U-Pb detrital zircon ages document that the Sierra de los Cuarzos formation reflects a vigorous mass wasting along the margin of the North American continental mainland, representing the eastern side of the Arperos back arc basin. Sandstones of the Sierra de los Cuarzos formation are free from detrital contributions related to the Guerrero terrane juvenile sources, indicating that the Arperos Basin acted like an efficient sedimentological barrier that inhibited the influence of the arc massifs on the continental mainland deposits. The Sierra de los Cuarzos formation is overlain by submarine slope deposits of the Pelones formation, which mark a sudden change in the depositional conditions. Provenance analysis documents that sandstones from the Pelones formation were fed by the mafic to intermediate arc assemblages of the Guerrero terrane, as well as by quartz-rich sources of the continental mainland, suggesting that, by the time of deposition of the Pelones

  11. Mixed volcanogenic-lithogenic sources for Permian bauxite deposits in southwestern Youjiang Basin, South China, and their metallogenic significance

    Science.gov (United States)

    Yu, Wenchao; Algeo, Thomas J.; Du, Yuansheng; Zhang, Qilian; Liang, Yuping

    2016-07-01

    Bauxite deposits at the base of the Upper Permian Heshan Formation in the Youjiang Basin, South China, contain zircons with dominant age peaks at 263-262 Ma. During the Middle to Late Permian, the Youjiang Basin consisted of a number of isolated and attached carbonate platforms separated by inter-platform troughs. The bauxite deposits are limited to the isolated carbonate platform facies and are not present on attached carbonate platforms and inter-platform troughs. Discriminant plots based on the trace element composition of the zircons indicate a combination of within-plate/anorogenic and arc-related/orogenic sources. Geochemical and isotopic data suggest that the metallogenic materials of the bauxite deposit came from felsic volcanic rocks of the Emeishan Large Igneous Provence (ELIP) in South China and from the Truong Son volcanic arc located between the South China and Indochina cratons. The northwestern and southeastern parts of the Youjiang Basin received larger amounts of ELIP detritus and volcanic arc detritus, respectively. Coarser siliciclastic material in proximal attached carbonate platform and inter-platform trough settings was delivered by rivers, but finer siliciclastics that accumulated on distally located carbonate platforms in isolated deep-water areas was probably transported by wind.

  12. Evidence for Metallogenic Geochemistry of Volcano-Hot Spring Deposition in Xiqiu Copper deposit,Zhejiang Province,China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There were strong volcanic and hot spring activities in Late proterozic in the Xiqiu mining district,Zhejiang province,The volcanic rocks and hydrothermal sedimentary cherts have high contents of the major metallogenic elements,Their atomic percentage of Cu:Zn:Pb is similar very much between volcanic rock,hydrothermal sedimentary chert and ore.Therefore,the metallization has a direct bearing on the volcanic and hot spring activities in the Xiqiu area.The δ34S values vary from -6.5‰to 2.8‰,the δ30Si Values from-0.2‰ to 0.6‰,and the δ18O Values from 8.14‰ to 22.32‰,Lead isotopes were derived mainly from the lower crust.The ores have high contents of As,Sb,Bi,Ga,Zn,and Ba,and low Al/(Al+Fe+Mn)ratios,with Zn/(Zn+Pb)ratios approximate to unity,Therefore,the Xiqiu massive copper sulfide deposit can be ascribed to volcano-hot spring deposition.

  13. Large clusters of gold deposits and large-scale metallogene-sis in the Jiaodong Peninsula, Eastern China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Jiaodong Peninsula is the largest repository of gold in China based on the production in history. It covers less than 0.2% of China's territory, but production of gold accounts for about one fourth of the whole country. Thus, the Jiaodong Peninsula is a typical area or case of large-scale metallogenesis and a large clusters of mineral deposits in China. It is characterized by the large clusters of gold deposits in large scale, high reserve and short mineralizing stage. In this study, we suggest that the eastern boundary of the large clusters of gold deposits is as same as that of North China Block, the gold deposits are hosted by Archean metamorphic rocks or Mesozoic granites, and the age of gold mineralization is 121.6 to 122.7 Ma. Gold and related ore-forming materials are derived from multisources, i.e. Archean metamorphic rocks, granites and intermediate-mafic dikes, especially, intermediate-mafic dikes and calc-alkaline granites. The metallogenic geodynamic process is constrained by the tectonic evolution of eastern North China Block during Late Mesozoic, and it is the result of the interaction between mantle and crust as the boundary plates are playing role on the block.

  14. Differences in plant cover and species composition of semiarid grassland communities of Central Mexico and its effects on net ecosystem exchange

    Directory of Open Access Journals (Sweden)

    J. Delgado-Balbuena

    2012-12-01

    Full Text Available Changes in land use across the semiarid grasslands of Northern Mexico have driven a decline of plant cover and alteration of plant species composition. A number of different plant communities have resulted from these changes, however, their implications on the carbon cycle and regional carbon balance are still poorly understood. Here, we examined the effects of plant cover loss and changes in species composition on net ecosystem CO2 exchange (NEE and their biotic and abiotic controls. Five typical plant community types were examined in the semiarid grassland by encasing the entire above-ground ecosystem using the geodesic dome method. Sites included an oat crop (crop, a moderately grazed grassland (moderate grazing, a 28 yr-old grazing exclosure (exclosure, an overgrazed site with low perennial grass cover (overgrazed, and an overgrazed site presenting shrub encroachment (shrub encroachment. For natural vegetation, rates of daytime NEE for sites with a high plant cover (exclosure and moderate grazing were similar (P>0.05 as compared to sites with low plant cover (overgrazed and shrub encroachment. However, night time NEE (carbon loss was more than double (P<0.05 for sites with high plant cover compared to sites with low cover, resulting into slight C sinks for the low plant cover sites and neutral or sources for the high plant cover sites on an annual basis. Differences in plant cover and its associated biomass defined the sensitivity to environmental controls. Thus, daytime NEE in low plant cover sites reached light compensation points at lower PPFD values than those from high plant cover sites. Differences in species composition did not influence NEE rates even though there were transient or permanent changes in C3 vs. C4 functional groups.

  15. Maize food group in the energy diets structure of mothers of native maize producers households in two communities in central Mexico

    Directory of Open Access Journals (Sweden)

    Mayra E. Moreno-Flores

    2014-06-01

    Full Text Available Introduction: To analyse the importance of Maize Food Group (MFG consumption by mothers of native maize households producers.Material and methods: It is the case of a descriptive, comparative, transversal and prospective study of two communities of the State of Mexico. Santa María Nativitas (SMN is a mestizo and peri-urban community and San Jerónimo Mavatí (SJM is an indigenous community. The selection of mothers to be studied was by convenience (40 women in SMN and 40 women in SJM. Interviews were used for application of food frequency questionnaires to record 24 hours food intake. Descriptive statistics and Kolmogorov-Smirnov test for normal distribution of the data was performed. Data were analysed using parametric statistics (Student’s t distribution and principal component analysis.Results: Mothers from SMN consume 3,999.93 Kcal/day from which 20% are from the MFG; while Mothers from SJM consume 2,566.67 Kcal from which 33.8% are from the MFG. There is not a significant difference between SMN and SJM regarding MFG consumption, but there is with respect to other food products like cereals, sweeteners, legumes and fruits.Conclusions: In both communities there was a change on mothers´ diet; more carbohydrates from cereals and sweet drinks are consumed. This change on diet has health consequences and impacts on maize diversity conservation, as the main source of food in rural communities, and foremost, on food security for agricultural communities.

  16. Environmental Impact Statement. Preliminary Draft. Realignment of Cannon Air Force Base, Curry County, New Mexico

    Science.gov (United States)

    1989-12-15

    New Mexico to the Gila, lower Rio Grande, middle Pecos, and Canadian valleys. It is seen occasionally in summer and as a breeding bird, with nests...ferret. The pine marten is present in the north central part of New Mexico in the San Juan and Sangre de Cristo mountains. Loss or alteration of...birds migrate southward to winter in the central Rio Grande Valley in New Mexico. The New Mexico population has increased to a population of 32I in

  17. Tracking recent climate and anthropogenic change in Central America in sediments form the lower fan of the Rio Yaqui, Gulf of California, Mexico

    Science.gov (United States)

    Aiello, I. W.; Ravelo, A. C.; Moraes, R.; Swarzenski, P. W.

    2015-12-01

    We report the results of preliminary sedimentologic analyses of a ~3.3m long piston core (P13) collected in the lower fan of the Rio Yaqui (Guaymas Basin, Gulf of California; depth, 1859m) by UNAM's (Universidad Nacional Autónoma de México) research ship El Puma in 2014. The core was collected to test the potential for high-resolution reconstructions of basin-scale paleoclimate in the Pacific and the Mesoamerican region. Shipboard and post-cruise analyses include magnetic susceptibility (MS), smear slide counts and laser diffraction particle size analysis. The core is being analyzed for X-Ray Fluorescence (XRF) and color reflectance, and a 210Pb age model is being constructed. Preliminary results show that Rio Yaqui lower fan sediment differs significantly from that in the Guaymas Basin, which is dominantly diatom ooze. The lower ~2m of core P13 show prominent alternations (~10-20cm) between very-fine-grained, clay intervals characterized by higher MS and mixed diatom and clay intervals, with coarser grain size and lower MS values. In contrast, the upper ~1m has distinctive high MS sand turbidites alternating with diatom-rich layers. Previous core studies from nearby ODP Leg 64 site show sedimentation rates of ~1.2 m/ka; as these sites are further away from the Yaqui delta the sedimentation rates for core P13 should be higher possibly recording only the last few hundred years of sedimentation. Clay/diatom cycles in the lower part of the core could record decadal- or ENSO-scale wet/aridity cycles in the Sonoran Mainland. Conversely, the coarser siliciclastic intervals and the diatom layers in the upper part of the core could reflect the last few decades of land usage in the watershed of the Rio Yaqui, the most important river in the state of Sonora, Mexico. These include large modifications to the river's hydrography (e.g. construction of dams and aqueducts), rapidly expanding mass agricultural practices in the region, and increased eutrophication in the Gulf.

  18. A new species of Auriculostoma (Digenea: Allocreadiidae) in the Mexican tetra Astyanax mexicanus (Actinopterygii: Characidae) from Central Veracruz, Mexico, described with the use of morphological and molecular data.

    Science.gov (United States)

    Razo-Mendivil, Ulises; Mendoza-Garfias, Berenit; de León, Gerardo Pérez-Ponce; Rubio-Godoy, Miguel

    2014-06-01

    Auriculostoma totonacapanensis n. sp. is described from the Mexican tetra, Astyanax mexicanus (Actinopterygii, Characidae) collected in a tributary creek of the Bobos River in Filipinas, Veracruz, Mexico. The new species is set apart from all congeners by the combination of some morphological characters such as the testes position (oblique in most specimens), the ventral to oral sucker ratio (1:1.2 × 1:1.1), the cirrus sac originating at the ovarian region, and by having vitelline follicles not confluent in the posttesticular region. Auriculostoma totonacapanensis n. sp. closely resembles Auriculostoma platense (Szidat, 1954) Scholz, Aguirre-Macedo, and Choudhury, 2004 and Auriculostoma diagonale Curran, Tkach and Overstreet, 2011 by possessing oblique testes; however, it differs from both species by possessing a genital pore located at level of the cecal bifurcation and by having vitelline follicles extending anteriorly up to the cecal bifurcation level, instead of a genital pore located between the anterior margin of the ventral sucker and cecal bifurcation, and vitelline follicles extending anteriorly to the mid level of the esophagus as in A. platense or to the pharynx level as in A. diagonale. Additionally, the new species differs from A. diagonale by having vitelline follicles not confluent or scarcely confluent in the posttesticular region rather than extensively confluent. Scanning electron microscopy micrographs of the new species demonstrated the presence of a single pair of muscular lobes on either side of the oral sucker, with a broad base, stretching from the ventrolateral to the dorsolateral side. Maximum parsimony and Bayesian inference analyses of the 28S rRNA gene sequences placed A. totonacapanensis as sister species of Auriculostoma astyanace Scholz, Aguirre-Macedo, and Choudhury, 2004 . Nucleotide variation between A. totonacapanensis and A. astyanace was 2.0% and 3.6% for the 28S rRNA gene and ITS2 sequences, respectively. Sequence variation

  19. Ground-water quality and susceptibility of ground water to effects from domestic wastewater disposal in eastern Bernalillo County, central New Mexico, 1990-91

    Science.gov (United States)

    Blanchard, Paul J.; Kues, Georgianna E.

    1999-01-01

    Eastern Bernalillo County is a historically rural, mountainous area east of Albuquerque, New Mexico. Historically, the primary economic activity consisted of subsistence farming and ranching and support of these activities from small communities. During the last 40 to 50 years, however, the area increasingly has become the site of residential developments. Homes in these developments typically are on 1- to 2-acre lots and are serviced by individual wells and septic systems. Between 1970 and 1990, the population of the area increased from about 4,000 to more than 12,000, and housing units increased from about 1,500 to more than 5,000. Results of analysis of water samples collected from 121 wells throughout eastern Bernalillo County in 1990 indicated that (1) total-nitrate concentrations in 10 samples exceeded the U.S. Environmental Protection Agency national primary drinking-water regulation maximum contaminant level of 10 milligrams per liter as nitrogen; (2) total-nitrate concentrations may be related to the length of time an area has been undergoing development; and (3) large dissolved-chloride concentrations may result from geologic origins, such as interbedded salt deposits or upward movement of saline ground water along faults and fractures, as well as from domestic wastewater disposal. Ground water throughout eastern Bernalillo County was assessed to be highly susceptible to contamination by overlying domestic wastewater disposal because (1) soils in more than 95 percent of eastern Bernalillo County were determined by the U.S. Department of Agriculture Natural Resources Conservation Service to have severe limitations for use as septic-system absorption fields and (2) a fractured carbonate geologic terrane, which typically has large secondary permeability and limited sorption capacity, is at the surface or underlying unconsolidated material in 73 percent of the area. Ground-water-level rises following an episodal precipitation event during July 22-27, 1991

  20. Students and Teachers' Reasons for Using the First Language Within the Foreign Language Classroom (French and English) in Central Mexico Razones de alumnos y maestros sobre el uso de la primera lengua en el salón de lenguas extranjeras (francés e inglés) en el centro de México

    OpenAIRE

    Irasema Mora Pablo; M. Martha Lengeling; Buenaventura Rubio Zenil; Troy Crawford; Douglas Goodwin

    2011-01-01

    The present study explores the use of the first language in a context of foreign language teaching. This qualitative research presents the classroom practice and points of view of French and English teachers and students within a public educational institute in central Mexico using the techniques of questionnaires and semi-structured interviews. The results show that teachers and the majority of students perceive the use of the first language as positive and part of the teaching and learning ...

  1. Study and thermodynamic characterization of the central area of the geothermal field Los Humeros, Puebla, Mexico; Estudio y caracterizacion termodinamica del sector centro del campo geotermico Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Pizano Herrera, Arturo; Machorro Jimenez, Manuel [Comision Federal de Electricidad, Perote, Veracruz (Mexico)

    1999-12-01

    Wells H-1, H-7, H-8, H-13 and H-40 are in the Central Sector of Los Humeros geothermal field. On the basis of production data analysis, two productive intervals were observed: the first between 1000 and 1500 masl, in the Augite Andesites with an average temperature of 250 Celsius degree; and the second between 650 and 1000 masl, observed in wells H-7, H-8 and H-40, with average temperatures of 280 Celsius degrees. The production mechanics are related to the presence of the Humeros-Maztaloya and Antigua faults. Wells H-13 and H-40 do not sustain production probably because although the drilling objectives were to penetrate geologic faults, this did not occur, resulting in a poor supply of geothermal fluids. In this zone, a calculation was made of the energy potential using volumetric analysis. This resulted in an estimated of 21 megawatts for the zone over a 20-years period, indicating that is possible to continuum exploiting the area. In the future, development wells must be drilled towards structural objectives and completed at depth of 2500 m. [Spanish] En el Sector Centro del Campo Geotermico de Los humeros se encuentran los pozos H-1, H-7, H-8, H-13 y H-40. La informacion analizada permite observar dos intervalos productores: el primero entre 1000 y 1500 msnm en las Andesitas de Augita, con una temperatura promedio de 250 grados Celsius y el segundo entre 650 y 1000 msnm, observado en los pozos H-7, H-8 y H-40, con 280 grados Celsius. La produccion de fluidos esta relacionada con las fallas Humeros-Maztaloya y Antigua. Los pozos H-13 y H-40 no sostienen su produccion, probablemente debido a que, pese a que su objetivo durante la perforacion fue intersectar fallas geologicas, al parecer estas quedaron alejadas de los mismos, ocasionando un aporte pobre de fluidos geotermicos. En esta zona se realizo un calculo del potencial energetico por medio de un analisis volumetrico; como resultado se estimo un potencial de generacion electrica de 21 MW durante un periodo

  2. The environmental policy in Mexico: Crisis and perspectives; La politica ambiental en Mexico: Crisis y perspectivas

    Energy Technology Data Exchange (ETDEWEB)

    Urquidi, Victor [Colegio de Mexico, Mexico, D. F. (Mexico)

    1996-12-31

    In this paper some aspects of the environmental situation in Mexico are condensed. The main roll performed by the modality of the energy resources consumption and the evolution of the environmental policy in Mexico from 1971 to 1996 is analyzed. It is concluded that in Mexico it has not been able to define the environmental policy in all its extension requiring, therefore, a greater participation of all the sectors to protect Nature and fight against the industrial and municipal pollution [Espanol] En esta ponencia se resumen algunos aspectos de la situacion ambiental actual de Mexico. Se analiza el papel central desempenado por la modalidad del consumo de energeticos y la evolucion de la politica ambiental en Mexico desde 1971 hasta 1996. Se concluye en que la politica ambiental en Mexico no se ha podido definir todavia en todos sus alcances por lo que se requiere una mayor participacion de todos los sectores para proteger la naturaleza y combatir la contaminacion industrial y municipal

  3. Effects of housing conditions and season on the activity rhythm of spider monkeys (Ateles geoffroyi) kept under natural conditions within their distributional range in Central Mexico.

    Science.gov (United States)

    Muñoz-Delgado, Jairo; Sánchez-Ferrer, José Carlos; Pérez-Galicia, Sergio; Canales-Espinosa, Domingo; Erkert, Hans G

    2014-11-01

    The timing and pattern of mammalian behavioral activities are regulated by an evolutionary optimized interplay of the genetically based biological (circadian) clock located in the brain's suprachiasmatic nuclei and direct responses to environmental factors that superimpose and thus mask the clock-mediated effects, the most important of which is the photically induced phase-setting (synchronization) of the circadian rhythmicity to the 24-hour solar day. In wild and captive animals living under the natural conditions prevailing in their habitat, to date, only a few attempts have been made to analyze the role of these two regulatory mechanisms in the species' adaptation to the time structure prevailing in their habitat. We studied the impact of housing conditions and season on the daily timing and pattern of activity in Mexican spider monkeys (Ateles geoffroyi). To this end, we carried out long-term activity recordings with Actiwatch® AW4 accelerometer/data-logger devices in 11 adult Ateles living under identical natural lighting and climatic conditions in either a large wire netting cage or a 0.25 ha forest enclosure in the primatological field station of Veracruz State University near Catemaco, Mexico. In a gravid female in the forest enclosure, we obtained first-hand information on the effect of late pregnancy and parturition on the monkey's activity rhythm. The Ateles behaved strictly diurnal and undertook about 90% of daily total activity during this activity time. Due to a higher second activity peak in late afternoon, the bimodal activity pattern was more pronounced in monkeys living in the forest enclosure. Although the spider monkeys kept there had an earlier activity onset and morning activity peak than their conspecifics in the cage, no consistent differences were found in the parameters characterizing the phase-setting of the circadian system to the environmental 24-h periodicity, either by comparison or correlation with the external time markers of

  4. Gangs in Central America

    Science.gov (United States)

    2008-10-17

    Citizen Security held in July 2008 indicated that Guatemala now has the second highest murder rate in Central America (roughly 45 per 100,000 people...training regional security forces.48 In recent years, the U.S. Southern Command has taken a leading role in discussing the problem of citizen security in...the results CRS-19 51 “Memo: The Merida Initiative and Citizen Security in Mexico and Central America,” Washington Office on Latin America, March 2008

  5. The lithosphere architecture and geodynamic of the Middle and Lower Yangtze metallogenic belt in eastern China: constraints from integrated geophysical data

    Science.gov (United States)

    Lü, Qingtian; Shi, Danian; Jiang, Guoming; Dong, Shuwen

    2014-05-01

    The lithosphere structure and deep processes are keys to understanding mineral system and ore-forming processes. Lithosphere-scale process could create big footprints or signatures which can be observed by geophysics methods. SinoProbe has conducted an integrated deep exploration across middle and lower reaches of Yangtze Metallogenic Belt (YMB) in Eastern China, these included broadband seismic, reflection seismic, wide-angle reflection and magnetotellurics survey. Seismic reflection profiles and MT survey were also performed in Luzong, Tongling and Ningwu ore districts to construct 3D geological model. The resulting geophysical data provides new information which help to better understanding the lithosphere structure, geodynamic, deformation and heat and mass transportation that lead to the formation of the Metallogenic Belt. The major results are: (1) Lower velocity body at the top of upper mantle and a SE dipping high velocity body were imaged by teleseismic tomography beneath YMB; (2) Shear wave splitting results show NE parallel fast-wave polarization direction which parallel with tectonic lineament; (3) The reflection seismic data support the crustal-detachment model, the lower and upper crust was detached during contraction deformation near Tanlu fault and Ningwu volcanic basin; (4) Broadband and reflection seismic confirm the shallow Moho beneath YMB; (5) Strong correlation of lower crust reflectivity with magmatism; (6) The lower crust below Luzong Volcanics shows obvious reflective anisotropy both at the crust-mantle transition and the brittle-ductile transition in the crust. All these features suggest that introcontinental subduction, lithosphere delamination, mantle sources magmatic underplating, and MASH process are responsible for the formation of this Mesozoic metallogenic belt. Acknowledgment: We acknowledge the financial support of SinoProbe by the Ministry of Finance and Ministry of Land and Resources, P. R. China, under Grant sinoprobe-03, and

  6. The lithosphere structure and deep processes of the Mesozoic metallogenic belt in eastern China: constraints from passive and active seismic methods

    Science.gov (United States)

    Lu, Q.; Shi, D.; Jiang, G.; Yan, J.

    2013-12-01

    The lithosphere structure and deep processes are keys to understanding mineral system and ore-forming processes. Lithosphere-scale process could create big footprints or signatures which can be observed by geophysics methods. SinoProbe-03 has conducted a Transect exploration across middle and lower Yangtze Metallogenic Belt (YMT) in Eastern China. Broadband seismic, reflection seismic, wide-angle reflection and magnetotellurics survey were carried out along the Transect. Seismic reflection profiles and MT survey were also performed in Luzong, Tongling and Ningwu ore districts to construct 3D geological model. The resulting geophysical data provides new information which help to better understanding the lithosphere structure, deep processes and deformation history of the Metallogenic Belt. The major results are: (1) Lower velocity body at the top of upper mantle and a SE dipping high velocity body were imaged by teleseismic tomography beneath YMB; (2) Shear wave splitting results show NE parallel fast-wave polarization direction which parallel with tectonic lineament; (3) The reflection seismic data support the crustal-detachment model, the lower and upper crust was detached during contraction deformation near Tanlu fault and Ningwu volcanic basin; (4) Broadband and reflection seismic confirm the shallow Moho beneath YMB; (5) Strong correlation of lower crust reflectivity with magmatism; (6) The lower crust below Luzong Volcanics shows obvious reflective anisotropy both at the crust-mantle transition and the brittle-ductile transition in the crust. All these features suggest that introcontinental subduction, lithosphere delamination, mantle sources magmatic underplating, and MASH process are responsible for the formation of this Mesozoic metallogenic belt. Acknowledgment: We acknowledge the financial support of SinoProbe by the Ministry of Finance and Ministry of Land and Resources, P. R. China, under Grant sinoprobe-03, and financial support by National Natural

  7. Primer registro de Harriota raleighiana (Chondrichthyes: Holocephali: Rhinochimaeridae en la costa del Pacífico central de México First record of Harriota raleighiana (Chondrichthyes: Holocephali: Rhinochimaeridae in the central Pacific coast of Mexico

    Directory of Open Access Journals (Sweden)

    José Luis Castro-Aguirre

    2007-12-01

    Full Text Available Este es el primer registro de la quimera narizona, Harriota raleighiana Goode y Bean 1895, en el litoral del Pacífico central de México, con base en una hembra moribunda, recolectada en la superficie del océano sobre agua muy profunda cerca de Manzanillo, Colima. También constituye el segundo registro de su existencia en el océano Pacífico oriental, lo que podría comprobar su patrón distribucional que la calificaría como cosmopolita. Se proporcionan sus medidas y algunos datos biológicos.This is the first record in Mexican central Pacific of the "longnosed chimaera" Harriota raleighiana Goode and Bean 1895, based on a nearly dead female specimen collected at sea surface over very deep water of Manzanillo, Colima. Also, it is the second published report on the occurrence of this species in the eastern Pacific ocean, and seems to support its geographical distribution pattern, which has been classified as cosmopolitan-like type. Morphometric and some biological data are also offered.

  8. Seeking a Rational Approach to a Regional Refugee Crisis: Lessons from the Summer 2014 “Surge” of Central American Women and Children at the US-Mexico Border

    Directory of Open Access Journals (Sweden)

    Karen Musalo

    2017-03-01

    Full Text Available In the early summer months of 2014, an increasing number of Central American children alone and with their parents began arriving at the US-Mexico border in search of safety and protection. The children and families by and large came from the Northern Triangle countries of El Salvador, Honduras, and Guatemala — three of the most dangerous countries in the world — to seek asylum and other humanitarian relief. Rampant violence and persecution within homes and communities, uncontrolled and unchecked by state authorities, compelled them to flee north for their lives. On the scale of refugee crises worldwide, the numbers were not huge. For example, 24,481 and 38,833 unaccompanied children, respectively, were apprehended by US Border Patrol (USBP in FY 2012 and FY 2013, while 68,631 children were apprehended in FY 2014 alone (USBP 2016a. In addition, apprehensions of “family units,” or parents (primarily mothers with children, also increased, from 15,056 families in FY 2013 to 68,684 in FY 2014 (USBP 2016b.[1] While these numbers may seem large and did represent a significant increase over prior years, they are nonetheless dwarfed by refugee inflows elsewhere; for example, Turkey was host to 1.15 million Syrian refugees by year end 2014 (UNHCR 2015a, and to 2.5 million by year end 2015 (UNHCR 2016 — reflecting an influx of almost 1.5 million refugees in the course of a single year. Nevertheless, small though they are in comparison, the numbers of Central American women and children seeking asylum at our southern border, concentrated in the summer months of 2014, did reflect a jump from prior years. These increases drew heightened media attention, and both news outlets and official US government statements termed the flow a “surge” and a “crisis” (e.g., Basu 2014; Foley 2014; Negroponte 2014. The sense of crisis was heightened by the lack of preparedness by the federal government, in particular, to process and provide proper custody

  9. Survey of hydrologic models and hydrologic data needs for tracking flow in the Rio Grande, north-central New Mexico, 2010

    Science.gov (United States)

    Tillery, Anne; Eggleston, Jack R.

    2012-01-01

    The six Middle Rio Grande Pueblos have prior and paramount rights to deliveries of water from the Rio Grande for their use. When the pueblos or the Bureau of Indian Affairs Designated Engineer identifies a need for additional flow on the Rio Grande, the Designated Engineer is tasked with deciding the timing and amount of releases of prior and paramount water from storage at El Vado Reservoir to meet the needs of the pueblos. Over the last three decades, numerous models have been developed by Federal, State, and local agencies in New Mexico to simulate, understand, and (or) manage flows in the Middle Rio Grande upstream from Elephant Butte Reservoir. In 2008, the Coalition of Six Middle Rio Grande Basin Pueblos entered into a cooperative agreement with the U.S. Geological Survey to conduct a comprehensive survey of these hydrologic models and their capacity to quantify and track various components of flow. The survey of hydrologic models provided in this report will help water-resource managers at the pueblos, as well as the Designated Engineer, make informed water-resource-management decisions that affect the prior and paramount water use. Analysis of 4 publicly available surface-water models and 13 publicly available groundwater models shows that, although elements from many models can be helpful in tracking flow in the Rio Grande, numerous data gaps and modeling needs indicate that accurate, consistent, and timely tracking of flow on the Rio Grande could be improved. Deficient or poorly constrained hydrologic variables are sources of uncertainty in hydrologic models that can be reduced with the acquisition of more refined data. Data gaps need to be filled to allow hydrologic models to be run on a real-time basis and thus ensure predictable water deliveries to meet needs for irrigation, domestic, stock, and other water uses. Timeliness of flow-data reporting is necessary to facilitate real-time model simulation, but even daily data are sometimes difficult to

  10. Biological pest control in Mexico.

    Science.gov (United States)

    Williams, Trevor; Arredondo-Bernal, Hugo C; Rodríguez-del-Bosque, Luis A

    2013-01-01

    Mexico is a megadiverse country that forms part of the Mesoamerican biological corridor that connects North and South America. Mexico's biogeographical situation places it at risk from invasive exotic insect pests that enter from the United States, Central America, or the Caribbean. In this review we analyze the factors that contributed to some highly successful past programs involving classical biological control and/or the sterile insect technique (SIT). The present situation is then examined with reference to biological control, including SIT programs, targeted at seven major pests, with varying degrees of success. Finally, we analyze the current threats facing Mexico's agriculture industry from invasive pests that have recently entered the country or are about to do so. We conclude that despite a number of shortcomings, Mexico is better set to develop biological control-based pest control programs, particularly on an area-wide basis, than many other Latin American countries are. Classical and augmentative biological control and SIT-based programs are likely to provide effective and sustainable options for control of native and exotic pests, particularly when integrated into technology packages that meet farmers' needs across the great diversity of production systems in Mexico.

  11. Tectonic evolution of the central-eastern sector of Trans Mexican Volcanic Belt and its influence on the eruptive history of the Nevado de Toluca volcano (Mexico)

    Science.gov (United States)

    Bellotti, F.; Capra, L.; Groppelli, G.; Norini, G.

    2006-11-01

    The Nevado de Toluca is an andesitic to dacitic stratovolcano of Late Pliocene-Holocene age located within the central and eastern sectors of the Trans Mexican Volcanic Belt. Morphostructural analysis, aerial photograph and satellite image interpretation, structural analysis and geological fieldwork were methods used to investigate the relationship between the evolution of the volcano and the tectonic framework of its basement. The study revealed that the area of Nevado de Toluca is affected by three main fault systems that intersect close to the volcanic edifice. These are from oldest to youngest, the Taxco-Querétaro, San Antonio and Tenango fault systems. The NNW-SSE Taxco-Querétaro fault system was active in the area since Early Miocene, and is characterized by right-lateral transtensive movement. Its reactivation during Early to Middle Pleistocene was responsible for the emplacement of andesitic to dacitic lava flows and domes of La Cieneguilla Supersynthem. The NE-SW San Antonio fault system was active during Late Pliocene, before the reactivation of the Taxco-Querétaro fault system, and is characterized by extensional left-lateral oblique-slip kinematics. The youngest is the E-W Tenango fault system that has been active since Late Pleistocene. This fault system is characterized by transtensive left-lateral strike-slip movement, and partly coeval with the youngest eruptive phase, the Nevado Supersynthem, which formed the present summit cone of the Nevado de Toluca volcano. The stress re-orientation from the Taxco-Querétaro to the Tenango fault system during Late Pleistocene is responsible for the ˜ 1 Ma hiatus in the magmatic activity between 1.15 Ma and 42 ka. After this period of repose, the eruptive style drastically changed from effusive to explosive with the emission of dacitic products. The methodology presented here furnish new data that can be used to better assess the complex structural evolution of this sector of the Trans Mexican Volcanic Belt

  12. Characterization of Near-Surface Geology and Possible Voids Using Resistivity and Electromagnetic Methods at the Gran Quivira Unit of Salinas Pueblo Missions National Monument, Central New Mexico, June 2005

    Science.gov (United States)

    Ball, Lyndsay B.; Lucius, Jeffrey E.; Land, Lewis A.; Teeple, Andrew P.

    2006-01-01

    At the Gran Quivira Unit of Salinas Pueblo Missions National Monument in central New Mexico, a partially excavated pueblo known as Mound 7 has recently become architecturally unstable. Historical National Park Service records indicate both natural caves and artificial tunnels may be present in the area. Knowledge of the local near-surface geology and possible locations of voids would aid in preservation of the ruins. Time-domain and frequency-domain electromagnetic as well as direct-current resistivity methods were used to characterize the electrical structure of the near-surface geology and to identify discrete electrical features that may be associated with voids. Time-domain electromagnetic soundings indicate three major electrical layers; however, correlation of these layers to geologic units was difficult because of the variability of lithologic data from existing test holes. Although resistivity forward modeling was unable to conclusively determine the presence or absence of voids in most cases, the high-resistivity values (greater than 5,000 ohm-meters) in the direct-current resistivity data indicate that voids may exist in the upper 50 meters. Underneath Mound 7, there is a possibility of large voids below a depth of 20 meters, but there is no indication of substantial voids in the upper 20 meters. Gridded lines and profiled inversions of frequency-domain electromagnetic data showed excellent correlation to resistivity features in the upper 5 meters of the direct-current resistivity data. This technique showed potential as a reconnaissance tool for detecting voids in the very near surface.

  13. "CEZAC 06": nueva variedad de ajo tipo Jaspeado para la región norte centro de México "CEZAC 06": new Jaspeado garlic cultivar for the northem-central region of Mexico

    Directory of Open Access Journals (Sweden)

    Manuel Reveles-Hernández

    2011-08-01

    Full Text Available Alrededor de 5 200 hectáreas de ajo son cultivadas en México donde la región norte centro, es una de las principales áreas productoras de esta hortaliza. La falta de variedades de ajo localmente adaptadas es una seria desventaja para los productores de ajo. En este reporte se mencionan las principales características agronómicas de "CEZAC 06", una nueva variedad de ajo disponible para los productores de los estados de Zacatecas, Aguascalientes, Durango, Chihuahua y Coahuila. Las principales ventajas de esta variedad son rendimientos más altos, bulbos consistentemente redondos, menor número de dientes por bulbo y maduración homogénea. En parcelas comerciales el rendimiento se ha mejorado en 9-17% y se han alcanzado rendimientos de hasta 30 t ha-1 con el uso de "CEZAC 06".About 5 200 hectares of garlic are cultivated in Mexico; the north-central region is one of the main producing areas of this vegetable. The lack of locally adapted varieties of garlic is a serious disadvantage for garlic producers. In this paper are mentioned the main agronomic characteristics of "CEZAC 06", a new garlic variety available for producers of Zacatecas, Aguascalientes, Durango, Chihuahua and Coahuila. The main advantages of this variety are higher yield, consistently round bulbs, fewer numbers of cloves per bulb and homogeneous maturation. In commercial plots, yield has improved in 9-17% and there have been achieved yields of up to 30 t ha-1 using "CEZAC 06".

  14. Metallogenic conditions and prospecting direction for Permian manganess deposits in Northern Guizhou%黔北二叠纪锰矿成矿条件与找矿方向

    Institute of Scientific and Technical Information of China (English)

    杜小全

    2011-01-01

    黔北地区二叠纪锰矿是中国南方重要的沉积锰矿床类型,在贵州的锰矿资源中占有重要的地位.开展区内二叠纪锰矿成矿条件与找矿方向的研究与探讨,对锰矿勘查工作部署意义重大.文章拟从黔北成锰盆地的古地理环境、岩相特征、锰质来源和锰矿赋存规律4个方面,分析区内二叠纪锰矿成矿条件,在此基础上提出找矿方向并对资源前景预测.%The Permian manganese deposits in Northern Guizhou, a main aedimentary type manganese deposit in Southem Chi na, play an important role in manganese mineral resources of Guizhou. It is meaningful to study regional metallogenic condition of Per mian manganese deposit for exploration. In this paper, the author analyzed metallogenic conditions of Permian manganese deposits from four aspects, i. e. , the paleo - geographical environment of the basin in which manganese deposit developed, lithofacie8 characteris ticts, source of mangancse, and hosting regularity of manganese deposits, and then proposed the prospecting direction and forecasting potential resource.

  15. Tectonic, magmatic, and metallogenic evolution of the Late Cretaceous arc in the Carpathian-Balkan orogen

    Science.gov (United States)

    Gallhofer, Daniela; Quadt, Albrecht von; Peytcheva, Irena; Schmid, Stefan M.; Heinrich, Christoph A.

    2015-09-01

    The Apuseni-Banat-Timok-Srednogorie Late Cretaceous magmatic arc in the Carpathian-Balkan orogen formed on the European margin during closure of the Neotethys Ocean. It was subsequently deformed into a complex orocline by continental collisions. The Cu-Au mineralized arc consists of geologically distinct segments: the Apuseni, Banat, Timok, Panagyurishte, and Eastern Srednogorie segments. New U-Pb zircon ages and geochemical whole rock data for the Banat and Apuseni segments are combined with previously published data to reconstruct the original arc geometry and better constrain its tectonic evolution. Trace element and isotopic signatures of the arc magmas indicate a subduction-enriched source in all segments and variable contamination by continental crust. The magmatic arc was active for 25 Myr (~92-67 Ma). Across-arc age trends of progressively younger ages toward the inferred paleo-trench indicate gradual steepening of the subducting slab away from the upper plate European margin. This leads to asthenospheric corner flow in the overriding plate, which is recorded by decreasing 87Sr/86Sr (0.70577 to 0.70373) and increasing 143Nd/144Nd (0.51234 to 0.51264) ratios over time in some segments. The close spatial relationship between arc magmatism, large-scale shear zones, and related strike-slip sedimentary basins in the Timok and Pangyurishte segments indicates mild transtension in these central segments of the restored arc. In contrast, the Eastern Srednogorie segment underwent strong orthogonal intraarc extension. Segmental distribution of tectonic stress may account for the concentration of rich porphyry Cu deposits in the transtensional segments, where lower crustal magma storage and fractionation favored the evolution of volatile-rich magmas.

  16. HAWC @ Mexico

    Science.gov (United States)

    Carramiñana, Alberto; González, María Magdalena; Salazar, Humberto; Alfaro, Ruben; Medina Tanco, Gustavo; Valdés Galicia, José; Delepine, David; Zepeda, Arnulfo; Villaseñor, Luis; Mendoza, Eduardo; Nava, Janina; Vázquez, Lilí; Tenorio Tagle, Guillermo; Carrasco, Luis; Silich, Sergey; Rogríguez Liñán, Gustavo; de la Fuente, Eduardo; Page, Dany; Lee, William; Dultzin, Deborah; Benitez, Erika; Ávila Reese, Vladimir; Mendoza, Sergio; Martos, Marco; Hernández Toledo, Héctor; Valenzuela, Octavio; Martínez, Oscar; Fernández, Arturo; Álvarez Ochoa, Cesar; Díaz, Lorenzo; Rosado, Alfonso; Ramírez, Cupatitzio; Menchaca, Arturo; Belmont, Ernesto; Sandoval, Andrés; Martínez, Arnulfo; Grabski, Varlen; Nellen, Lukas; D'Olivo, Juan Carlos; Lara, Alejandro; Caballero, Rogelio; Moreno, Gerardo; Napsuciale, Mauro; Ureña, Luis; Reyes, Marco; Migénes, Victor; Herrera, Gerardo; Saavedra, Oscar; Carrillo, Alejandro; Carrasco Nuñez, Gerardo; Vargas, Carlos

    The High Altitude Water Cerenkov detector HAWC will be a powefull instrument to survey the TeV sky. Mexico has proposed to locate this experiment in the Parque Nacional Pico de Orizaba, between Citlaltepetl and Tliltepetl, host of the Large Millimeter Telescope (LMT). The region has a sizeable technical infrastructure related to the LMT and we recently studied a 4100m location in terms of its feasibility to host HAWC. We present the proposed site location and extension, its water acquisition, experimental and complementary infrastructures.

  17. STUDY ON TECTONIC FEATURE AND METALLOGENIC MECHANISM OF THE PENGSHAN Sn-Pb-Zn POLYMETALLIC OREFIELD,JIANGXI PROVINCE

    Institute of Scientific and Technical Information of China (English)

    LU Shudong; DU Yangsong; XIAO E; XU Chunwei

    2005-01-01

    The Pengshan Sn-Pb-Zn polymetallic orefield is located in the Jiujiang-Ruichang region, which is a segment of the middle-lower Yangtze River metallogenic belt. The Pengshan late Yanshanian buried pluton with granitic composition is a calc-alkaline pluton, intrusion of which is responsible for the formation of the Sn-Pb-Zn polymetallic deposit through providing thermodynamic condition and ore-forming material.The long-active basement rifts initially formed in the Jinning period and the domal structure with induced secondary order faults formed by emplacement of the pluton, such as ring-detachment fault,top-detachment fault and joint fissure, act as the passage-way for magma and ore-forming fluid and impounding structure for ore deposit. The magma to form the pluton with DI>90 is intensively differentiated. The variation of the ore-forming fluid in composition with falling in temperature caused by action of magmatic hydrothermal convection system combined with groundwater convection system attributes to mineralization of various types in the orefield. The mineralization process can be divided into six stages, i.e., greisenization, skarnization of early stage, fluorite-stanniferous silication stage, skarnization of advanced stage, quartz and cassiterite-sulfuration stage and carbonation stage. The mineral assemblages formed in different mineralization stages are different owing to temperature changing and may be overlapped in space. Malayaite is recognized from the mineral assemblage formed in the fluorite-stanniferous silication stage. The ores in the Pengshan Sn-Pb-Zn polymetallic deposit are spatially zoned with variation from As-Sn mineral assemblage of high temperature in the inner zone through Sn-Pb and Pb-Zn-Ag mineral assemblage of middle temperature in the middle zone to fluorite mineral assemblage of low temperature in the outer zone.The exchanging of Sn,Mg and Fe between biotite and hydrothermal fluid resulted from variation of physicochemical condition

  18. Mexico Gravity Data per 2 min Cell (97)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 2' gravity density grid for Mexico, North-Central America, and the Western Caribbean Sea shows the distribution of about one million terrestrial and marine...

  19. Gulf of Mexico Sperm Whale Acoustic Prey Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Large vessel surveys were conducted during the summer of 2009 and the winter of 2010 in the north-central Gulf of Mexico to examine the spatial distribution of sperm...

  20. Gulf of Mexico sperm whale photo-ID catalog

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Photo-identification data on sperm whales occupying the north central Gulf of Mexico have been collected during vessel surveys. Photographs of sperm whales are taken...

  1. Gulf of Mexico Marine Mammal Vessel Surveys - NRDA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Large vessel surveys were conducted during June-August and Oct-Nov, 2010 in the north central Gulf of Mexico to collect data on marine mammal spatial distribution...

  2. Phylogeographic characteristics of vesicular stomatitis New Jersey viruses circulating in Mexico from 2005 to 2011 and their relationship to epidemics in the United States.

    Science.gov (United States)

    Velazquez-Salinas, Lauro; Pauszek, Steven J; Zarate, Selene; Basurto-Alcantara, Francisco J; Verdugo-Rodriguez, Antonio; Perez, Andres M; Rodriguez, Luis L

    2014-01-20

    We analyzed the phylogenetic and time-space relationships (phylodynamics) of 181 isolates of vesicular stomatitis New Jersey virus (VSNJV) causing disease in Mexico and the United States (US) from 2005 through 2012. We detail the emergence of a genetic lineage in southern Mexico causing outbreaks in central Mexico spreading into northern Mexico and eventually into the US. That emerging lineage showed higher nucleotide sequence identity (99.5%) than that observed for multiple lineages circulating concurrently in southern Mexico (96.8%). Additionally, we identified 58 isolates from Mexico that, unlike previous isolates from Mexico, grouped with northern Central America clade II viruses. This study provides the first direct evidence for the emergence and northward migration of a specific VSNJV genetic lineage from endemic areas in Mexico causing VS outbreaks in the US. In addition we document the emergence of a Central American VSNJV genetic lineage moving northward and causing outbreaks in central Mexico.

  3. Anthropometric variation in west-central Mexico.

    Science.gov (United States)

    Christensen, A F

    2001-06-01

    Anthropometric data from five indigenous Mexican groups, collected by Carlos and Manuel Basauri in 1933, were reanalyzed and compared with serological and cranial non-metric data. Ten cranial and 14 postcranial measurements were used, both separately and together. Bias-corrected r0 and FST values were slightly higher for the postcranial analysis (0.033) than for the cranial analysis (0.024). Given the degree of linguistic differentiation among the Mexican populations, not to mention the different histories of the communities sampled, this result is surprisingly low. The two groups which were closest linguistically and geographically, the Cora and Huichol, were also close biologically. The other three groups, Tarascan, Aztecan, and Otomi, were not closely related to each other or to the Cora-Huichol pair. More interesting than the relationship between populations in this case are those within them. The Aztecas of Tuxpan, Jalisco, exhibit high rii values and lower-than-expected phenotypic variance, suggesting the pronounced action of genetic drift. The Otomi of Ixmiquilpan and Cora of the Sierra de Nayarit, despite their very different histories, both exhibit low rii values and higher-than-expected phenotypic variance, indicating a high level of gene flow. Despite the phenotypic similarities between the Cora and Huichol, their residual variance is very different; this mirrors serological investigations of relative admixture. Over all, recent population history, and especially non-indigenous admixture, are at least as explicative of the observed biological variation as historical linguistic ties are.

  4. Mexico; Mexique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-01

    This document summarizes the key energy data for Mexico: 1 - energy organizations and policy: Ministry of energy (SENER), Comision Reguladora de Energia (CRE), Ministry of Finances, Ministry of trade and industrial development (SECOFI), national commission for energy savings (CONAE); 2 - companies: federal commission of electricity (CFE), Minera Carbonifera Rio Escondido (MICARE - coal), Pemex (petroleum); 3 - energy production: resources, electric power, petroleum, natural gas; 4 - energy consumption; 5 - stakes and perspectives. Some economic and energy indicators are summarized in a series of tables: general indicators, supply indicators (reserves, refining and electric capacity, energy production, foreign trade), demand indicators (consumption trends, end use, energy independence, energy efficiency, CO{sub 2} emissions), energy status per year and per energy source. (J.S.)

  5. Is the Mesa Central of Mexico a biogeographical province? Descriptive analysis based on freshwater biotic components ¿La mesa central de México es una provincia biogeográfica? Análisis descriptivo basado en componentes bióticos dulceacuícolas

    Directory of Open Access Journals (Sweden)

    Omar Domínguez-Domínguez

    2009-12-01

    Full Text Available This essay presents an analysis of the concept of Mesa Central of México as a potential biogeographical province. This region of México has been used as a reference for describing species richness and distribution patterns of the freshwater fish fauna. However, it has not been recognized as a biogeographical province in the available schemes which are mostly based on the composition of terrestrial biota. Here, we provide a historical sketch of the way the concept of Mesa Central arose in the literature as a physiographic province, and we provide a comparison with respect to the regionalization schemes of the Mexican territory, which are based on attributes such physiography, elevation, hydrology, geology and biogeography. We conclude that the Mesa Central, even though it represents a practical concept for establishing the distribution pattern of the fish fauna, in the way it was described originally cannot be circumscribed to any of the regions or provinces in which Mexico has been divided. We also argue that this geographical region cannot be considered as a synonym of the Transmexican Volcanic Axis biogeographical province, and also that it is possible that the fact that this area is not circumscribed to any regionalization scheme is due to the fact that freshwater elements have not been considered in the establishment of such biogeographical regions. We end by pointing out the need for a biogeographical analysis that integrates most of the freshwater elements in order to determine whether both the aquatic and terrestrial flora and fauna are driven by the same geobiotic processes.En este ensayo se presenta un análisis del concepto de Mesa Central de México como una posible provincia biogeográfica. Esta región del país ha sido utilizada como referencia para describir la riqueza y distribución de una parte importante de la fauna ictiológica dulceacuícola, sin embargo, no es reconocida como provincia biogeográfica en ninguno de los

  6. Current (2004-07) Conditions and Changes in Ground-Water Levels from Predevelopment to 2007, Southern High Plains Aquifer, East-Central New Mexico-Curry County, Portales, and Causey Lingo Underground Water Basins

    Science.gov (United States)

    Tillery, Anne

    2008-01-01

    The Southern High Plains aquifer is the principal aquifer in Curry and Roosevelt Counties, N. Mex., and primary source of water in southeastern New Mexico. Successful water-supply planning for New Mexico's Southern High Plains requires knowledge of the current aquifer conditions and a context to estimate future trends given current aquifer-management policy. This report provides a summary of the current (2007) water-level status of the Southern High Plains aquifer in New Mexico, including a basis for estimating future trends by comparison with historical conditions. This report includes estimates of the extent of ground-water level declines in the Curry County, Portales, and Causey-Lingo Ground-water Management Area parts of the High Plains Aquifer in eastern New Mexico since predevelopment. Maps representing 2007 water levels, water-level declines, aquifer saturated thickness, and depth to water accompanied by hydrographs from representative wells for the Southern High Plains aquifer in the Curry County, Portales, and Causey Lingo Underground Water Basins were prepared in cooperation with the New Mexico Office of the State Engineer. The results of this mapping show the water level declined as much as 175 feet in the study area at rates as high as 1.76 feet per year.

  7. PGE patterns of ores of Dajing Cu-polymetallic deposit in Linxi County, Inner Mongolia: Indicator to source of metallogenic elements

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By comparing PGE patterns of sulfide ores with that of basic-ultrabasic dikes occurring in the Dajing Cu-polymetallic deposit, we discover that there are similar positive slopes between the basic-ultrabasic dikes and the black ores composed mainly of sphalerite and galena, reflecting affinity of their source. The PGE patterns of the yellow ores composed basically of chalcopyrite, arsenopyrite and pyrite are actually different. One is close to the pattern of the mantle lherzolite, and others resemble the pattern of the basic rocks. However, the concentrations of Ru are higher in the yellow ores, reflecting that sulfur attains or approaches saturation in their parent magma. The PGE characteristics of ores and dikes show that the magmas derived from the deep of crust and the metallogenic elements were supplied mainly by growth material of the crust. In addition, the mantle-derived magma also offered some elements.

  8. 辽东半岛滨海砂金矿成矿规律%Metallogenic Regularity of the Coastal Gulch-gold Deposit in Liaodong Peninsula

    Institute of Scientific and Technical Information of China (English)

    刘长纯; 姚志宏; 孙鹏慧

    2016-01-01

    Liaodong peninsula coastal gulch-gold mine is not development,less resources,in order to provide the theoretical reference for the prospecting work of coastal gulch-gold deposit in Liaodong pen-insula,the metallogenic conditions of the coastal gulch-gold deposit are analyzed,the results show that:①the new archean strata and ancient proterozoic strata are developed in Liaodong peninsula,intrusive rocks and native gold deposits (points)with the characteristics of more material source and multi-stage forma-tion;②the climatic conditions along the Yellow sea coast are conducive to weathering and erosion,with more rainfall and large rive transport capacity,a large number of ore-forming materials are transported for the gulch-gold deposit;③the favorable metallogenic environment for the formation of coastal gulch-gold deposits is provided by the abundant land physiognomy,sea bottom physiognomy,coastal types physiogno-my and Quaternary type physiognomy with alluvial-diluvial causes;④the new tectonic movement is mainly for overall lift long up,which caused the the peninsula suffered the strong erosion in the entire Quaterna-ry,so,the sufficient material source for the gulch-gold deposit is provided.Based on the above analysis re-sults,the metallogenic material source,metallogemnic dynamic and metallogenic environment are dis-cussed from the aspects of ore-forming material supply conditions,climate and hydrodynamic conditions and sedimentary environment.The above study results can provide some reference for the prospecting work of coastal gulch-gold deposit in Liaodong peninsula.%辽东半岛滨海砂金矿不发育、资源量少,为进一步加强寻找滨海砂金矿,对滨海砂金矿的成矿条件进行了分析,结果表明:①区内具有新太古、古中元古代地层,侵入岩和原生金矿床(点)具有多物质来源和形成的多阶段性;②半岛黄海沿岸的气候条件有利于风化剥蚀作用的进行,伴随着降雨较多

  9. Alteration mineral mapping and metallogenic prediction using CASI/SASI airborne hyperspectral data in Mingshujing area of Gansu Province, NW China

    Science.gov (United States)

    Sun, Yu; Zhao, Yingjun; Qin, Kai; Tian, Feng

    2016-04-01

    Hyperspectral remote sensing is a frontier of remote sensing. Due to its advantage of integrated image with spectrum, it can realize objects identification, superior to objects classification of multispectral remote sensing. Taken the Mingshujing area in Gansu Province of China as an example, this study extracted the alteration minerals and thus to do metallogenic prediction using CASI/SASI airborne hyperspectral data. The Mingshujing area, located in Liuyuan region of Gansu Province, is dominated by middle Variscan granites and Indosinian granites, with well developed EW- and NE-trending faults. In July 2012, our project team obtained the CASI/SASI hyperspectral data of Liuyuan region by aerial flight. The CASI hyperspectral data have 32 bands and the SASI hyperspectral data have 88 bands, with spectral resolution of 15nm for both. The hyperspectral raw data were first preprocessed, including radiometric correction and geometric correction. We then conducted atmospheric correction using empirical line method based on synchronously measured ground spectra to obtain hyperspectral reflectance data. Spectral dimension of hyperspectral data was reduced by the minimum noise fraction transformation method, and then purity pixels were selected. After these steps, image endmember spectra were obtained. We used the endmember spectrum election method based on expert knowledge to analyze the image endmember spectra. Then, the mixture tuned matched filter (MTMF) mapping method was used to extract mineral information, including limonite, Al-rich sericite, Al-poor sericite and chlorite. Finally, the distribution of minerals in the Mingshujing area was mapped. According to the distribution of limonite and Al-rich sericite mapped by CASI/SASI hyperspectral data, we delineated five gold prospecting areas, and further conducted field verification in these areas. It is shown that there are significant gold mineralized anomalies in surface in the Baixianishan and Xitan prospecting

  10. Time distribution of the main Brazilian mineral deposits. 2: metallogenic epochs; Distribuicao no tempo geologico dos principais depositos minerais brasileiros. 2: epocas metalogeneticas

    Energy Technology Data Exchange (ETDEWEB)

    Biondi, Joao C. [Parana Univ., Curitiba, PR (Brazil). Dept. de Geologia]. E-mail: jcbiondi@setuva.geologia.ufpr.br

    1999-12-01

    The metallogenic epochs of the main mineral deposit groups were defined with base on the ore's of the 194 main Brazilian mineral deposits. Mineral deposits are rare on epochs that: precede the beginning of juvenile accretion peak periods, and/or of cooling of rocks formed during each of the main brazilian thermo-tectonic events. Deposits are more frequent on epochs that are coincident or immediately younger than these peak periods. The most important metallogenic epoch, with about 30% of the selected deposits, is between 50 Ma and the Recent, and corresponds to the formation of supergenic and/or residual and placer deposits. Brazilian's volcanogenic (VHMS), Mississippi Valley (MTV) and mesothermal gold-lode deposits have discordant ages as compared with their equivalents in other countries, while deposits believed to be SEDEX have concordant ages. With the exception of Urucum, the primary iron and manganese ores of brazilian deposits are Archean. Primary tin deposits from Amazonas, Amapa and Goias State cluster between 1500 and 2300 Ma. Tin deposits from Rondonia and Mato Grosso are more recent and most formed between 1000 and 1600 Ma, in sequence with the other groups of tin deposits. Uranium deposits vary on genetic model and ages, due to the mobility of the element in all geologic environments. Most part of Brazilian deposits of phosphate, titanium, niobium, Rare Earths, diamond in kimberlites and of amethyst formed during the Mesozoic, and arte genetically related to the alkaline and basaltic magmatism that affected the brazilian territory in this period. Gemstone (tourmaline and aquamarine), talc and magnesite deposits are more frequent in the Brasiliano period. Gipsite, silvite and barite occur in Senonian to Aptian evaporites. (author)

  11. Foliicolous fungi from Arctostaphylos pungens in Mexico

    NARCIS (Netherlands)

    Moreno-Rico, Onésimo; Groenewald, Johannes Z; Crous, Pedro W

    2014-01-01

    Arctostaphylos pungens "Manzanita" is an important shrub in the southwestern USA, and northern and central Mexico. Manzanita bears apple-like fruit that is utilised for a range of edible products. Over the past two years, several foliar disease problems were noted on this host in the San José de Gra

  12. Angiostoma lamotheargumedoi n. sp. (Nematoda: Angiostomatidae from the intestine of Pseudoeurycea mixteca (Caudata: Plethodontidae in central Mexico Angiostoma lamotheargumedoi n. sp. (Nematoda: Angiostomatidae del intestino de Pseudoeurycea mixteca (Caudata: Plethodontidae en la región central de México

    Directory of Open Access Journals (Sweden)

    Jorge Falcón-Ordaz

    2008-08-01

    Full Text Available A new species of Angiostoma (Angiostomatidae is described from the intestine of the plethodontid salamander, Pseudoeurycea mixteca from Puebla State, in central Mexico. The new species closely resembles Angiostoma limancis, Angiostoma kimmeriensis, Angiostoma spiridonovi, Angiostoma stammeri, and Angiostoma carettae, because they all possess 8 pairs of pedunculate papillae in the caudal region; however, the new species can be distinguished by the unique arrangement of papillae, with 1 pre-cloacal pair, and 7 post-cloacal pairs. Among the 12 congeneric species of Angiostoma described so far, 2 have been described as parasites of salamanders, Angiostoma plethodontis from Plethodon cinereus and Plethodon richmondi in Virginia, USA, and Angiostoma onychodactyla from Onychodactylus japonicus in Japan. Angiostoma lamotheargumedoi n. sp. is readily distinguished from these 2 species by the presence of lateral alae and by the number of pre-cloacal papillae.En este trabajo se describe una especie nueva del género Angiostoma (Angiostomatidae como parásito del intestino de la salamandra pletodóntida Pseudoeurycea mixteca en el estado de Puebla, en el centro de México. La nueva especie es morfológicamente similar a Angiostoma limancis, Angiostoma kimmeriensis, Angiostoma spiridonovi, Angiostoma stammeri y Angiostoma carettae, porque todas ellas poseen 8 pares de papilas pedunculadas en la región caudal; sin embargo, se puede distinguir de éstas por el arreglo característico de dichas papilas: 1 par en posición precloacal y 7 pares postcloacales. Dos de las 12 especies congenéricas de Angiostoma fueron descritas de salamandras, Angiostoma plethodontis de Plethodon cinereus y Plethodon richmondi en Virginia, EUA y Angiostoma onychodactyla de Onychodactylus japonicus en Japón. Angiostoma lamotheargumedoi n. sp. se distingue fácilmente de estas 2 especies por la presencia de alas laterales y por el número de papilas precloacales.

  13. New Mexico Ghost Towns

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data provides locations and non-spatial attributes of many ghost towns in the State of New Mexico, compiled from various sources. Locations provided with...

  14. New Mexico Parks

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the locations of parks in New Mexico, in point form, with limited attributes, compiled using available data from a...

  15. New Mexico National Cemeteries

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The United States Department of Veterans Affairs National Cemetery Administration maintains 2 national cemeteries in the state of New Mexico; the Fort Bayard...

  16. New Mexico State Parks

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the generalized physical boundaries of New Mexico State Parks, in polygonal form with limited attributes, compiled using...

  17. Natural Hazards In Mexico City