Sample records for andean porphyry copper

  1. Porphyry copper deposits of the world (United States)

    U.S. Geological Survey, Department of the Interior — Information on porphyry copper deposits from around the world with grade and tonnage models, a general classification based on geologic setting, mineralogy, with...

  2. Preliminary Model of Porphyry Copper Deposits (United States)

    Berger, Byron R.; Ayuso, Robert A.; Wynn, Jeffrey C.; Seal, Robert R., II


    The U.S. Geological Survey (USGS) Mineral Resources Program develops mineral-deposit models for application in USGS mineral-resource assessments and other mineral resource-related activities within the USGS as well as for nongovernmental applications. Periodic updates of models are published in order to incorporate new concepts and findings on the occurrence, nature, and origin of specific mineral deposit types. This update is a preliminary model of porphyry copper deposits that begins an update process of porphyry copper models published in USGS Bulletin 1693 in 1986. This update includes a greater variety of deposit attributes than were included in the 1986 model as well as more information about each attribute. It also includes an expanded discussion of geophysical and remote sensing attributes and tools useful in resource evaluations, a summary of current theoretical concepts of porphyry copper deposit genesis, and a summary of the environmental attributes of unmined and mined deposits.

  3. Duobaoshan Porphyry Copper Deposit and Its Associated Components

    Institute of Scientific and Technical Information of China (English)


    @@Duobaoshan porphyry copper deposit, situated in Nenjiang County of Heilongjiang Province, Northeast China, lies tectonically in the Mongolian-Okhotsk geosyncline.Duobaoshan porphyry copper ore field consisting of Duobaoshan copper deposit and Tongshan copper deposit contains rich copper associated with molybdenum, gold, silver and osmium (OsX87). In this sense, this porphyry copper ore field will turn into a large industrial base of copper, gold, silver and osmium. At present, in Duobaoshan porphyry copper deposit occurs a usable B+C+-D grade reserve of 3 276 630ton Cu, 122 920 ton Mo, 87 ton gold and 1 417 ton Ag.

  4. Analysis of tectonic settings of global superlarge porphyry copper deposits

    Institute of Scientific and Technical Information of China (English)

    XIA; Bin(夏斌); CHEN; Genwen(陈根文); WANG; He(王核)


    About three quarters of superlarge porphyry copper deposits throughout the world occur along the eastern Pacific basin rim, most of which were formed during the Mesozoic-Cenozoic. Porphyry copper deposits often occur in the upper parts of a subduction zone and in a within-plate orogenic belt. Some porphyry copper deposits are inconsistent with plate subduction with respect to their formation time, and most of them in the world are associated with tensional environment. Metallogenic porphyries originated from the mantle, and the involvement of the lower-crust or oceanic crust materials have played an important role. Based on the geochemical characteristics and tectonic settings of the ore-bearing porphyries in the Gandise and Yulong metallogenic zones, it is proposed that delamination may be the important mechanism of formation of porphyry copper deposits.

  5. Porphyry copper enrichment linked to excess aluminium in plagioclase (United States)

    Williamson, B. J.; Herrington, R. J.; Morris, A.


    Porphyry copper deposits provide around 75%, 50% and 20% of world copper, molybdenum and gold, respectively. The deposits are mainly centred on calc-alkaline porphyry magmatic systems in subduction zone settings. Although calc-alkaline magmas are relatively common, large porphyry copper deposits are extremely rare and increasingly difficult to discover. Here, we compile existing geochemical data for magmatic plagioclase, a dominant mineral in calc-alkaline rocks, from fertile (porphyry-associated) and barren magmatic systems worldwide, barren examples having no associated porphyry deposit. We show that plagioclase from fertile systems is distinct in containing `excess’ aluminium. This signature is clearly demonstrated in a case study carried out on plagioclase from the fertile La Paloma and Los Sulfatos copper porphyry systems in Chile. Further, the presence of concentric zones of high excess aluminium suggests its incorporation as a result of magmatic processes. As excess aluminium has been linked to high melt water contents, the concentric zones may record injections of hydrous fluid or fluid-rich melts into the sub-porphyry magma chamber. We propose that excess aluminium may exclude copper from plagioclase, so enriching the remaining melts. Furthermore, this chemical signature can be used as an exploration indicator for copper porphyry deposits.

  6. Isotope geology of the bakircay porphyry copper prospect, northern turkey (United States)

    Taylor, R. P.


    Isotopic data for the Bakircay granodiorite porphyry, MediaObjects/126_2005_BF01798964_f1.tif give a Late Eocene age for the development of the porphyry copper system. They suggest a close temporal and genetic relationship between igneous and hydrothermal activity, and indicate that magmatic-hydrothermal fluids produced potassic alteration and that meteoric fluids enriched in radiogenic87Sr were responsible for propylitic alteration. The granodiorite porphyry is petrologically similar to porphyry copper-related intrusions from island arc and continental margin settings, which form a group with initial87Sr/86Sr ratios of less than 0. 7043, representing magmas produced in tectonic environments lacking any important component of old (i. e. Precambrian) continental material.

  7. Late Cretaceous porphyry copper mineralization in Sonora, Mexico: Implications for the evolution of the Southwest North America porphyry copper province (United States)

    Barra, Fernando; Valencia, Victor A.


    Two porphyry Cu-Mo prospects in northern Sonora, Mexico (Fortuna del Cobre and Los Humos) located within the southwestern North American porphyry province have been dated in order to constrain the timing of crystallization and mineralization of these ore deposits. In Fortuna del Cobre, the pre-mineralization granodiorite porphyry yielded an U-Pb zircon age of 76.5 ± 2.3 Ma, whereas two samples from the ore-bearing quartz feldespathic porphyry were dated at 74.6 ± 1.3 and 75.0 ± 1.4 Ma. Four molybdenite samples from Los Humos porphyry Cu prospect yielded a weighted average Re-Os age of 73.5 ± 0.2 Ma, whereas two samples from the ore-bearing quartz monzonite porphyry gave U-Pb zircon ages of 74.4 ± 1.1 and 74.5 ± 1.3 Ma, showing a Late Cretaceous age for the emplacement of this ore deposit. The results indicate that Laramide porphyry Cu mineralization of Late Cretaceous age is not restricted to northern Arizona as previously thought and provide evidence for the definition of NS trending metallogenic belts that are parallel to the paleo-trench. Porphyry copper mineralization follows the inland migration trend of the magmatic arc as a result of the Farallon slab flattening during the Laramide orogeny.

  8. Tectonic environments of South American porphyry copper magmatism through time revealed by spatiotemporal data mining (United States)

    Butterworth, N.; Steinberg, D.; Müller, R. D.; Williams, S.; Merdith, A. S.; Hardy, S.


    Porphyry ore deposits are known to be associated with arc magmatism on the overriding plate at subduction zones. While general mechanisms for driving magmatism are well established, specific subduction-related parameters linking episodes of ore deposit formation to specific tectonic environments have only been qualitatively inferred and have not been formally tested. We develop a four-dimensional approach to reconstruct age-dated ore deposits, with the aim of isolating the tectonomagmatic parameters leading to the formation of copper deposits during subduction. We use a plate tectonic model with continuously closing plate boundaries, combined with reconstructions of the spatiotemporal distribution of the ocean floor, including subducted portions of the Nazca/Farallon plates. The models compute convergence rates and directions, as well as the age of the downgoing plate through time. To identify and quantify tectonic parameters that are robust predictors of Andean porphyry copper magmatism and ore deposit formation, we test two alternative supervised machine learning methods; the "random forest" (RF) ensemble and "support vector machines" (SVM). We find that a combination of rapid convergence rates ( 100 km/Myr), subduction obliquity of 15°, a subducting plate age between 25-70 Myr old, and a location far from the subducting trench boundary (>2000 km) represents favorable conditions for porphyry magmatism and related ore deposits to occur. These parameters are linked to the availability of oceanic sediments, the changing small-scale convection around the subduction zone, and the availability of the partial melt in the mantle wedge. When coupled, these parameters could influence the genesis and exhumation of porphyry copper deposits.

  9. The geology and geochemistry of Philippine Porphyry copper deposits (United States)

    Divis, Allan F.

    Porphyry copper deposits and their relationship to felsic intrusions are of considerable economic as well as academic interest. They generally occur near continental margins and in island arcs. Although some conjecture exists as to the ultimate source of transition metals associated with the deposits, a growing body of evidence suggests the metals are principally derived from a magmatic source: the porphyry intrusions. These intrusions may also give rise to adjacent vein and precious metal deposits. Over 40 potential deposits have been reported in the Philippine island arc and approximately nine are or have been in production. The known and inferred reserves from these deposits exceed three billion metric tons of ore— approximately 10 to 20 million tons of metallic copper. Several deposits may ultimately have more than a billion tons of ore reserves. There appears to be a remarkable correlation between the timing of porphyry intrusions in the Philippines and that in other areas, particularly New Guinea and the Solomon Islands. These intrusions also show a close relationship to the timing of oceanic plate tectonic processes. Periods of increased subduction rate and accompanying dilation and/or shearing within the arc may be conducive to the generation of porphyry magmas on an episodic rather than continuous basis. Ultimately, the development of an economically significant ore body requires the presence of a hydrous magma and may be associated with other primary compositional characteristics. However, anomalous high primary magmatic concentrations of copper do not appear to be required for the formation of the porphyry deposits. The Philippine porphyry intrusions differ somewhat from `continental' porphyries and are chemically similar to mineralized island arc intrusions of the Carribean and the southwest Pacific. The Philippine intrusions generally range from diorites and quartz diorites to low potassium granodiorites. Initial 87-Sr/86-Sr ratios are low, ranging

  10. Porphyry copper assessment of the Tibetan Plateau, China: Chapter F in Global mineral resource assessment (United States)

    Ludington, Steve; Hammarstrom, Jane M.; Robinson,, Gilpin R.; Mars, John L.; Miller, Robert J.


    The U.S. Geological Survey collaborated with the China Geological Survey to conduct a mineral-resource assessment of resources in porphyry copper deposits on the Tibetan Plateau in western China. This area hosts several very large porphyry deposits, exemplified by the Yulong and Qulong deposits, each containing at least 7,000,000 metric tons (t) of copper. However, large parts of the area are underexplored and are likely to contain undiscovered porphyry copper deposits.

  11. Porphyry copper assessment of western Central Asia: Chapter N in Global mineral resource assessment (United States)

    Berger, Byron R.; Mars, John L.; Denning, Paul D.; Phillips, Jeffrey D.; Hammarstrom, Jane M.; Zientek, Michael L.; Dicken, Connie L.; Drew, Lawrence J.; with contributions from Alexeiev, Dmitriy; Seltmann, Reimar; Herrington, Richard J.


    The U.S. Geological Survey conducted an assessment of resources associated with porphyry copper deposits in the western Central Asia countries of Kyrgyzstan, Uzbekistan, Kazakhstan, and Tajikistan and the southern Urals of Kazakhstan and Russia as part of a global mineral resource assessment. The purpose of the study was to (1) delineate permissive areas (tracts) for undiscovered porphyry copper deposits; (2) compile a database of known porphyry copper deposits and significant prospects; (3) where data permit, estimate numbers of undiscovered deposits within those permissive tracts; and (4) provide probabilistic estimates the amounts of copper (Cu), molybdenum (Mo), gold (Au), and silver (Ag) that could be contained in those undiscovered deposits.

  12. Potential links between porphyry copper deposits and exhumed metamorphic basement complexes in northern Chile (United States)

    Cooper, Frances; Docherty, Alistair; Perkins, Rebecca


    Porphyry copper deposits (PCDs) are typically associated with magmatic arcs in compressional subduction zone settings where thickened crust and fractionated calc-alkaline magmas produce favourable conditions for copper mineralisation. A classic example is the Eocene-Oligocene PCD belt of Chile, the world's leading copper producing country. In other parts of the world, older late Cretaceous to early Tertiary PCDs are found in regions of former subduction-related magmatism that have undergone subsequent post-orogenic crustal extension, such as the Basin and Range province of western North America, and the Eurasian Balkan-Carpathian-Dinaride belt. In the Basin and Range there is a striking correlation between the location of many PCDs and exhumed metamorphic core complexes (isolated remnants of the middle to lower crust exhumed during extensional normal faulting). This close spatial relationship raises questions about the links between the two. For example, are their exhumation histories related? Could the presence of impermeable metamorphic rocks at depth affect and localise mineralising fluids? In Chile there appears to be a similar spatial relationship between PCDs and isolated outcrops of exhumed metamorphic basement. In northern Chile, isolated exposures of high-grade metamorphic gneisses and amphibolites are thought to be exhumed remnants of the pre-subduction Proterozoic-Paleozoic continental margin of Gondwana [2], although little is known about when they were exhumed and by what mechanism. For example, the Limón Verde metamorphic complex, exhumed from a depth of ca. 50 km, is situated adjacent to Chuquicamata, the largest open pit copper mine in the world. In northernmost Chile, another metamorphic exposure, the Belén complex, sits close to the Dos Hermanos PCD, a small deposit that is not actively mined. Comprising garnet-bearing gneisses and amphibolites, the Belén is thought to have been exhumed from a depth of ca. 25 km, but when and how is unclear [3

  13. Porphyry-copper mineralisation in the central Srednogorie zone, Bulgaria (United States)

    Strashimirov, Strashimir; Petrunov, Rumen; Kanazirski, Milko


    The porphyry-copper systems in the central part of the Srednogorie zone (Bulgaria) are represented by three major deposits (Elatsite, Medet and Assarel) and several smaller deposits and occurrences, all of them within the Panagyurishte ore district. The hydrothermal systems are related to Late Cretaceous calc-alkaline igneous complexes. Ore mineralisation is developed predominantly in the apical parts of subvolcanic and intrusive bodies as well as within the volcanic and basement metamorphic rocks. Several of the porphyry systems are spatially associated with shallow-level intermediate and high-sulphidation volcanic-hosted epithermal deposits of economic importance, such as the major gold-copper mine at Chelopech located 10 km from the Elatsite porphyry-copper deposit. Mineralisation processes in the porphyry deposits start with intensive hydrothermal alteration of the wall rocks. K-silicate alteration is characteristic for pre-ore hydrothermal activity in all of them, and it is located mostly in their central parts. Propylitic alteration is prominent in the Medet and Assarel deposits. The Assarel deposit is located in the central part of a palaeovolcanic structure and shows a large spectrum of pre-ore alterations, including propylitic, sericitic, and advanced argillic assemblages. The initial stages of the hydrothermal systems are characterised by high temperatures (>550-500 °C) and highly saline (50-20 wt% NaCl equiv.) and vapour-rich fluids of likely magmatic origin. The composition of the fluids gradually changes from H2O-NaCl±FeCl2 to H2O-NaCl-KCl and H2O-NaCl-dominated as the fluids cool, react with wall rocks, and may become diluted with meteoric water. Fe-Ti-oxide mineral associations were formed early in all deposits, later followed, in the Elatsite deposit, by an assemblage of bornite, chalcopyrite, platinum group element (PGE) phases, Co-Ni thiospinels, Ag- and Bi-tellurides, and selenides. The main ore stage in all deposits is dominated by

  14. Re-Os Dating of the Pulang Porphyry Copper Deposit in Zhongdian, NW Yunnan, and Its Geological Significance

    Institute of Scientific and Technical Information of China (English)

    ZENG Pusheng; HOU Zengqian; WANG Haiping; QU Wenjun; MENG Yifeng; YANG Zhusen; LI Wenchang


    The Pulang porphyry copper deposit is located in the Zhongdian island arc belt, NW Yunnan, in the central part of the Sanjiang area, SW China, belonging to the southern segment of the Yidun island arc belt on the western margin of the Yangtze Platform. In the Yidun island arc, there occur well-known "Gacun-style" massive sulfide deposits in the northern segment and plenty of porphyry copper deposits in the southern segment, of which the Pulang porphyry copper deposit is one of the representatives. Like the Yulong porphyry copper deposit, this porphyry copper deposit is also one of the most important porphyry copper deposits in the eastern Qinghai-Tibet Plateau. But it is different from other porphyry copper deposits in the eastern Qinghai-Tibet Plateau (e.g. those in the Gangdise porphyry copper belt and Yulong porphyry copper belt) in that it formed in the Indosinian period, while others in the Himalayan period. Because of its particularity among the porphyry copper deposits of China, this porphyry copper deposit is of great significance for the study of the basic geology and the evaluation and prediction of mineral resources in the Zhongdian island arc belt.However, no accurate chronological data are available for determining the timing of mineralization of the porphyry copper deposit. By field observation in the study area and Re-Os dating of molybdenite and K-Ar dating of hydrothermal minerals and whole rock from the typical geological bodies, the timing of mineralization of the porphyry copper deposit has systematically been determined for the first time. The K-Ar age for the hydrothermal mineralization of biotite-quartz monzonitic porphyry that has undergone patassic silicate (biotite and K-feldspar) alteration ranges from 235.4±2.4 to 221.5±2.0 Ma and the Re-Os age for molybdenite in the quartz-molybdenite stage is ~213±3.8 Ma. These data are very close to each other, suggesting that the ore-forming processes of the Pulang porphyry copper deposit was

  15. Porphyry copper assessment of Southeast Asia and Melanesia: Chapter D in Global mineral resource assessment (United States)

    Hammarstrom, Jane M.; Bookstrom, Arthur A.; Dicken, Connie L.; Drenth, Benjamin J.; Ludington, Steve; Robinson,, Gilpin R.; Setiabudi, Bambang Tjahjono; Sukserm, Wudhikarn; Sunuhadi, Dwi Nugroho; Wah, Alexander Yan Sze; Zientek, Michael L.


    The U.S. Geological Survey collaborated with member countries of the Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP) on an assessment of the porphyry copper resources of Southeast Asia and Melanesia as part of a global mineral resource assessment. The region hosts world-class porphyry copper deposits and underexplored areas that are likely to contain undiscovered deposits. Examples of known porphyry copper deposits include Batu Hijau and Grasberg in Indonesia; Panguna, Frieda River, and Ok Tedi in Papua New Guinea; and Namosi in Fiji.

  16. Porphyry copper assessment of eastern Australia: Chapter L in Global mineral resource assessment (United States)

    Bookstrom, Arthur A.; Len, Richard A.; Hammarstrom, Jane M.; Robinson,, Gilpin R.; Zientek, Michael L.; Drenth, Benjamin J.; Jaireth, Subhash; Cossette, Pamela M.; Wallis, John C.


    The U.S. Geological Survey (USGS) conducts national and global assessments of resources (mineral, energy, water, and biologic) to provide science in support of decision making. Mineral resource assessments provide syntheses of available information about where mineral deposits are known and suspected to occur in the Earth’s crust and which commodities may be present, together with estimates of amounts of resources that may be present in undiscovered deposits. The USGS collaborated with geologists of the Geological Survey of New South Wales and Geoscience Australia (formerly the Australian Geological Survey Organisation) on an assessment of Phanerozoic-age porphyry copper resources in Australia. Porphyry copper deposits contain about 11 percent of the identified copper resources in Australia. This study addresses resources of known porphyry copper deposits and expected resources of undiscovered porphyry copper deposits in eastern Australia.


    Institute of Scientific and Technical Information of China (English)

    刘德权; 唐延龄; 周汝洪


    Through the study on the geology and metallogenic environment ofthe giant Tuwu porphyry copper deposit in Hami to Jueluotag porphyry copper meatllogenic belt, it is concluded that those deposits formed in the active continental margin during the middle to late convergent stage of the orogenesis. Comparing with Pacific Rim porphyry copper belt, the favorite tectonic environment is "Andean", i.e., the fan shaped structure. It is also recognized that Xinjiang has the similar geological and metallgenic environment with the porphyry copper belts in adjacent countries and/or districts, and then there is good potential for finding large and giant porphyry copper deposits, especially in Western Tianshan, Western Kunlun, Muzitag, Qimantag, south of Eastern Jungger, etc. areas.%对哈密土屋地区斑岩铜矿和觉罗塔格斑岩铜矿成矿带的成矿地质条件进行了研究,其形成于造山带汇聚阶段中-后期的活动陆缘环境。与环太平洋斑岩铜矿对比,有利成矿的构造类型为"安第斯型",即扇形形态构造;与新疆周边国家和地区斑岩铜矿成矿带对比,新疆具有相类似的成矿地质条件,找矿远景很大,特别是西天山、西昆仑、木孜塔格、祁漫塔格、东准噶尔南部等地区,具有斑岩铜矿成矿的广阔前景,有希望找到新的大型-超大型铜矿床。

  18. Genetic Model of an Aborted Porphyry-copper System (United States)

    Papp, D. C.; Nitoi, E.; Szakacs, A.


    The Neogene Sturzii shallow intrusion from the East Carpathians (Bargau Mts., Romania), hosted by Paleogene-Miocene sediments of the Transcarpatian Flysch, developed as an immature porphyry copper structure. It consists of small volumes of dacites, andesites and related contact breccias, having a surface exposure of a few km2. Hydrothermal alteration occurred in the inner part of the intrusive body. The related mineralization consists of pyrite and chalcopyrite either as small veins or disseminated within the rock. A genetic model of the intrusive structure has been developed based on an integrated petrographic, geochemical, isotopic, fluid inclusion and geophysical study. The rapidly ascending calc-alkaline magmas that generated the intrusion are mantle-derived and contaminated with lower-crustal material. Pressure estimations for amphibole reveal significant differences between values corresponding to the crystal cores and rims, suggesting that decompression occurred during its crystallization. The occurrence of exploded fluid inclusions, as well as of primary igneous garnet, also indicate decompression regime during magma uplift and/or storage. All fluid inclusions identified in dacites are aqueous; C-N-S species were not detected. The general evolution of the fluids is toward decreasing salinity with decreasing temperature. Early high-T, high salinity fluids, most likely of magmatic origin, were subjected to a boiling event, related to a change of fluid pressure from litho- to hydrostatic, and followed by dilution with meteoric fluids as indicated by low salinities. These characteristics of the fluids suggest the tendency of the intrusion to evolve towards a porphyry copper system. We estimate that the evolution stopped due to decompression that allowed cold and dilute external fluids to enter the system and because of the small size of the intrusion that cooled down rapidly and could not induce extensive and long-lasting fluid circulation. Since there is no

  19. Geochronologic constraints on magmatic intrusions and mineralization of the Zhunuo porphyry copper deposit in Gangdese, Tibet

    Institute of Scientific and Technical Information of China (English)


    In situ zircon U-Pb ages for the recently discovered Zhunuo porphyry copper deposit in the western part of the Gangdese metallogenic belt in Tibet were determined by sensitive high-resolution ion microprobe (SHRIMP). The ages can be divided into two separate groups, reflecting more than four major tectono-magmatic events in the area. The 62.5±2.5 Ma age of inherited zircons may be related to the volcanic eruption of the Linzizong Group formed shortly after the India-Asia continental collision. The 50.1±3.6 Ma age most likely corresponds to the time of underplating of mantle-derived mafic magma in Gangdese. The 15.6±0.6 Ma age obtained from magmatic zircons is interpreted as the age of crystallization of the Zhunuo ore-forming porphyry. Finally, a molybdenite Re-Os isochron age of 13.72±0.62 Ma is consistent with another zircon U-Pb age of 13.3 ±0.2 Ma, representing the time of copper mineralization. These ages, in combination with available literature data, indicate that magmatic crystallization and copper mineralization in the Gangdese metallogenic belt became gradually younger westward, and further suggest that the Zhunuo porphyry copper deposit was formed in the same tectonic stage as other porphyry copper deposits in the eastern and central Gangdese belt. This conclusion provides critical information for future exploration of porphyry copper deposits in western Gangdese.

  20. Tempo of magma degassing and the genesis of porphyry copper deposits (United States)

    Chelle-Michou, Cyril; Rottier, Bertrand; Caricchi, Luca; Simpson, Guy


    Porphyry deposits are copper-rich orebodies formed by precipitation of metal sulphides from hydrothermal fluids released from magmatic intrusions that cooled at depth within the Earth’s crust. Finding new porphyry deposits is essential because they are our largest source of copper and they also contain other strategic metals including gold and molybdenum. However, the discovery of giant porphyry deposits is hindered by a lack of understanding of the factors governing their size. Here, we use thermal modelling and statistical simulations to quantify the tempo and the chemistry of fluids released from cooling magmatic systems. We confirm that typical arc magmas produce fluids similar in composition to those that form porphyry deposits and conclude that the volume and duration of magmatic activity exert a first order control on the endowment (total mass of deposited copper) of economic porphyry copper deposits. Therefore, initial magma enrichment in copper and sulphur, although adding to the metallogenic potential, is not necessary to form a giant deposit. Our results link the respective durations of magmatic and hydrothermal activity from well-known large to supergiant deposits to their metal endowment. This novel approach can readily be implemented as an additional exploration tool that can help assess the economic potential of magmatic-hydrothermal systems.

  1. Ore-forming fluid constraints on illite crystallinity (IC) at Dexing porphyry copper deposit, Jiangxi Province

    Institute of Scientific and Technical Information of China (English)


    Illite, a distinctive kind of clay minerals of potassiumalteration within the hydrothermal alteration zone, frequently occurs at the Tongchang porphyry copper deposit ore field. The illite crystallinity (IC) value and expandability are mainly affected by water/rock ratio or fluid flux. It was formed by illitization of plagioclase and micas during hydrothermal fluid-rock interaction within the porphyry body and near the contact zone with wall rocks. Moreover, the negative correlation between illite index (IC) and copper grade indicates that within the alteration zone, the smaller the illite crystallinity value, the higher the alteration degree, and the higher the copper grade due to higher water/rock ratio. At lower levels of the porphyry body, however, the illite crystallinity (IC) values are mainly controlled by temperature and time duration.

  2. Research on remote sensing assessment technology for porphyry copper in south of Arequipa province of Peru (United States)

    Yang, Rihong; Li, Zhizhong; Cheng, Xiufa; Zhao, Yuling


    The study area is located in the middle section of Andean metallogenic zone. Excellent mineralization geological conditions make it the most principal Porphyry Copper Deposits (PCDs) distribution area in southern Peru and there are several super-large PCDs for hundreds of kilometers in every direction. The regional metallogenic regularity of this area is controlled by the NNW fault parallel to the trench on the west of the South American continent. Small porphyry rocks are very common in this area (circular structure pattern in remote sensing image) with typical zoned alteration of PCD - potassic alteration, argillic alteration, phyllic alteration and propylitization (most exposed) from inside to the outside on the surface. These geologic features can be recognized and extracted by using remote sensing image data. Accordingly, the reflectivity curve of main altered minerals of the typical alteration zones of PCD was rebuilt which was corresponded to B1-B9 of ASTER satellite data, based on the altered mineral assemblages and their spectral characteristics of the typical alteration zones of PCD, and ASTER data's ability of identifying minerals with argillic alteration and carbonatite alteration. Based on the standard spectral data of USGS, We found that the information of argillic-and phyllic- altered minerals assemblages in the typical alteration zones can be extracted in the principal components analysis pattern based on ASTER B1467 while the information of propylitization altered minerals in the principal components analysis pattern based on ASTER B1348 with larger reflectivity of B9 than B8, after comparing and analyzing comprehensively the spectral curve characteristics of main altered minerals. In this method, altered minerals assemblages of argillic-and phyllic- altered zone and propylitization altered zone in this study area was extracted, and the results agree well with the distribution of known PCD. Meanwhile, remote sensing geological interpretation has

  3. El Salvador, Chile porphyry copper deposit revisited: Geologic and geochronologic framework (United States)

    Cornejo, P.; Tosdal, R.M.; Mpodozis, C.; Tomlinson, A.J.; Rivera, O.; Fanning, C.M.


    The Eocene (42 to 41 Ma) El Salvador porphyry copper deposit in the Indio Muerto district, northern Chile (26?? 15??? S Lat.), formerly thought to have formed at the culmination of a 9-m.y. period of episodic magmatism, is shown by new mapping, U-Pb and K-Ar geochronology, and petrologic data to have formed during the younger of two distinct but superposed magmatic events - a Paleocene (???63 to 58 Ma) and an Eocene (44 to 41 Ma) event. In the district, high-K Paleocene volcano-plutonic activity was characterized by a variety of eruptive styles and magmatic compositions, including a collapse caldera associated with explosive rhyolitic magmatism (El Salvador trap-door caldera), a post-collapse rhyolite dome field (Cerro Indio Muerto), and andesitic-trachyandesitic stratovolcanos (Kilo??metro Catorce-Los Amarillos sequence). Precaldera basement faults were reactivated during Paleocene volcanism as part of the collapse margin of the caldera. Beneath Cerro Indio Muerto, where the porphyry Cu deposit subsequently formed, the intersection of two major basement faults and the NNE-striking rotational axis of tilted ignimbrites of the Paleocene El Salvador caldera localized emplacement of post-collapse rhyolite domes and peripheral dikes and sills. Subsequent Eocene rhyolitic and granodioritic-dacitic porphyries intruded ???14 m.y. after cessation of Paleocene magmatism along the same NNE-striking structural belt through Cerro Indio Muerto as did the post-collapse Paleocene rhyolite domes. Eocene plutonism over a 3-m.y. period was contemporaneous with NW-SE-directed shortening associated with regional sinistral transpression along the Sierra Castillo fault, lying ???10 km to the east. Older Eocene rhyolitic porphyries in the Indio Muerto district were emplaced between 44 and 43 Ma, and have a small uneconomic Cu center associated with a porphyry at Old Camp. The oldest granodioritic-dacitic porphyries also were emplaced at ???44 to 43 Ma, but their petrogenetic relation to

  4. Magnetotelluric survey to characterize the Sunnyside porphyry copper system in the Patagonia Mountains, Arizona (United States)

    Rodriguez, Brian D.; Sampson, Jay A.


    The Sunnyside porphyry copper system is part of the concealed San Rafael Valley porphyry system located in the Patagonia Mountains of Arizona. The U.S. Geological Survey is conducting a series of multidisciplinary studies as part of the Assessment Techniques for Concealed Mineral Resources project. To help characterize the size and resistivity of the mineralized area beneath overburden, a regional east-west magnetotelluric sounding profile was acquired. This is a data release report of the magnetotelluric sounding data collected along the east-west profile; no interpretation of the data is included.

  5. Audio-magnetotelluric survey to characterize the Sunnyside porphyry copper system in the Patagonia Mountains, Arizona (United States)

    Sampson, Jay A.; Rodriguez, Brian D.


    The Sunnyside porphyry copper system is part of the concealed San Rafael Valley porphyry system located in the Patagonia Mountains of Arizona. The U.S. Geological Survey is conducting a series of multidisciplinary studies as part of the Assessment Techniques for Concealed Mineral Resources project. To help characterize the size, resistivity, and skin depth of the polarizable mineral deposit concealed beneath thick overburden, a regional east-west audio-magnetotelluric sounding profile was acquired. The purpose of this report is to release the audio-magnetotelluric sounding data collected along that east-west profile. No interpretation of the data is included.

  6. Stochastic modelling of deep magmatic controls on porphyry copper deposit endowment (United States)

    Chiaradia, Massimo; Caricchi, Luca


    Porphyry deposits, our main source of copper and of significant amounts of Mo, Re and Au, form at convergent margins in association with intermediate-felsic magmas. Although it is accepted that copper is transported and precipitated by fluids released by these magmas, the magmatic processes leading to the formation of economic deposits remain elusive. Here we perform Monte Carlo petrological and geochemical modelling to quantitatively link crustal magmatic processes and the geochemical signatures of magmas (i.e., Sr/Y) to the formation of porphyry Cu deposits of different sizes. Our analysis shows that economic deposits (particularly the largest ones) may only form in association with magma accumulated in the lower-middle crust (P > ~0.5 GPa) during ≥2–3 Ma, and subsequently transferred to and degassed in the upper crust over periods of up to ~2.0 Ma. Magma accumulation and evolution at shallower depths (<~0.4 GPa) dramatically reduces the potential of magmatic systems to produce economic deposits. Our modelling also predicts the association of the largest porphyry deposits with a specific Sr/Y interval (~100 ± 50) of the associated magmatic rocks, which is virtually identical to the range measured in giant porphyry copper deposits.

  7. Zircon U-Pb dating of Maherabad porphyry copper-gold prospect area: evidence for a late Eocene porphyry-related metallogenic epoch in east of Iran

    Directory of Open Access Journals (Sweden)

    Azadeh Malekzadeh Shafaroudi


    Full Text Available Eastern Iran has great potential for porphyry copper deposits, as a result of its past subduction zone tectonic setting that lead to extensive alkaline to calc-alkaline magmatic activity in Tertiary time. Maherabad is the first porphyry Cu-Au prospecting area which is discovered in eastern Iran. This is related to a succession o f monzonitic to dioritic porphyries stocks that were emplaced within volcanic rocks. Monzonitic porphyries have basic role in mineralization. Hydrothermal alteration zones are well developed including potassic, sericitic-potassic, quartz-sericite-carbonate-pyrite, quartz-carbonate-pyrite, silicified-propylitic, propylitic, carbonate and silicified zones. Mineralization occurs as Disseminated, stockwork and hydrothermal breccia. Based on early stage of exploration, Cu is between 179- 6830 ppm (ave. 3200 ppm and Au is up to 1000 ppb (ave. 570 ppb. This prospect is gold- rich porphyry copper deposit. Laser-ablation U-Pb dating of two samples from ore-related intrusive rocks indicate that these two monzonitic porphyries crystallized at 39.0 ± 0.8 Ma to 38.2 ± 0.8 Ma, within a short time span of less than ca. 1 Ma during the middle Eocene. This provides the first precise ages for metallogenic episode of porphyry-type mineralization. Also, the initial 87Sr/86Sr and (143Nd/144Ndi was recalculated to an age of 39 Ma. Initial 87Sr/86Sr ratios for monzonitic rocks are 0.7047-0.7048. The (143Nd/144Ndi isotope composition are 0.512694-0.512713. Initial ε Nd isotope values 1.45-1.81. Based on isotopic data the magma had originated beyond the continental crust. The study will be used for tectonic-magmatic setting and evolution of eastern Iran. Keywords: Lut block, Middle Eocene, Zircon, Geochronology, Laser ablation ICP-MS,

  8. Global mineral resource assessment: porphyry copper assessment of Mexico: Chapter A in Global mineral resource assessment (United States)

    Hammarstrom, Jane M.; Robinson,, Gilpin R.; Ludington, Steve; Gray, Floyd; Drenth, Benjamin J.; Cendejas-Cruz, Francisco; Espinosa, Enrique; Pérez-Segura, Efrén; Valencia-Moreno, Martín; Rodríguez-Castañeda, José Luis; Vásquez-Mendoza, Rigobert; Zürcher, Lukas


    Mineral resource assessments provide a synthesis of available information about distributions of mineral deposits in the Earth’s crust. A probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in Mexico was done as part of a global mineral resource assessment. The purpose of the study was to (1) delineate permissive areas (tracts) for undiscovered porphyry copper deposits within 1 km of the surface at a scale of 1:1,000,000; (2) provide a database of known porphyry copper deposits and significant prospects; (3) estimate numbers of undiscovered deposits within those permissive tracts; and (4) provide probabilistic estimates of amounts of copper (Cu), molybdenum (Mo), gold (Au), and silver (Ag) that could be contained in undiscovered deposits for each permissive tract. The assessment was conducted using a three-part form of mineral resource assessment based on mineral deposit models (Singer, 1993). Delineation of permissive tracts primarily was based on distributions of mapped igneous rocks related to magmatic arcs that formed in tectonic settings associated with subduction boundary zones. Using a GIS, map units were selected from digital geologic maps based on lithology and age to delineate twelve permissive tracts associated with Jurassic, Laramide (~90 to 34 Ma), and younger Tertiary magmatic arcs. Stream-sediment geochemistry, mapped alteration, regional aeromagnetic data, and exploration history were considered in conjunction with descriptive deposit models and grade and tonnage models to guide estimates.

  9. Isotopic tracing of ore-forming source materials for Dexing porphyry copper deposit of Jiangxi, China

    Institute of Scientific and Technical Information of China (English)

    Peng QIAN; Jianjun LU


    Dexing copper deposit is the biggest porphyry copper deposit in China. By researching isotopes of C,Si and Cu from the samples of Tongchang and Fujiawu ore-field, the authors found that δ13CPDB values of siderite were close to the δ13CPDB value of original magma; δ30Si values of the samples at the ore-forming stage were close to the δ30Si value range of magma, δ30Si values of partial samples were far away from it; Cu isotopic compositions of massive chalcopyrite formed at the early ore-forming stage are higher than that of veinal chalcopyrite formed at the later ore-forming stage. The results show that ore-forming materials were mainly derived from the porphyry body, and part of them were from wall rock materials.

  10. Porphyry copper assessment of Europe, exclusive of the Fennoscandian Shield: Chapter K in Global mineral resource assessment (United States)

    Sutphin, David M.; Hammarstrom, Jane M.; Drew, Lawrence J.; Large, Duncan E.; Berger, Byron R.; Dicken, Connie L.; DeMarr, Michael W.; with contributions from Billa, Mario; Briskey, Joseph A.; Cassard, Daniel; Lips, Andor; Pertold, Zdeněk; Roşu, Emilian


    The U.S. Geological Survey (USGS) collaborated with European geologists to assess resources in porphyry copper deposits in Europe, exclusive of Scandinavia (Sweden, Denmark, Norway, and Finland) and Russia. Porphyry copper deposits in Europe are Paleozoic and Late Cretaceous to Miocene in age. A number of the 31 known Phanerozoic deposits contain more than 1 million metric tons of contained copper, including the Majdanpek deposit, Serbia; Assarel, Bulgaria; Skouries, Greece; and Rosia Poeni, Romania. Five geographic areas were delineated as permissive tracts for post-Paleozoic porphyry copper deposits. Two additional tracts were delineated to show the extent of permissive igneous rocks associated with porphyry copper mineralization related to the Paleozoic Caledonian and Variscan orogenies. The tracts are based on mapped and inferred subsurface distributions of igneous rocks of specific age ranges that define areas where the occurrence of porphyry copper deposits within 1 kilometer of the Earth’s surface is possible. These tracts range in area from about 4,000 to 93,000 square kilometers. Although maps at a variety of different scales were used in the assessment, the final tract boundaries are intended for use at a scale of 1:1,000,000.

  11. Porphyry copper assessment of the Tethys region of western and southern Asia: Chapter V in Global mineral resource assessment (United States)

    Zürcher, Lukas; Bookstrom, Arthur A.; Hammarstrom, Jane M.; Mars, John C.; Ludington, Stephen; Zientek, Michael L.; Dunlap, Pamela; Wallis, John C.; Drew, Lawrence J.; Sutphin, David M.; Berger, Byron R.; Herrington, Richard J.; Billa, Mario; Kuşcu, Ilkay; Moon, Charles J.; Richards, Jeremy P.; Zientek, Michael L.; Hammarstrom, Jane M.; Johnson, Kathleen M.


    A probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in the Tethys region of western and southern Asia was carried out as part of a global mineral resource assessment led by the U.S. Geological Survey (USGS). The purpose of the study was to delineate geographic areas as permissive tracts for the occurrence of porphyry copper deposits at a scale of 1:1,000,000 and to provide probabilistic estimates of amounts of copper likely to be contained in undiscovered porphyry copper deposits in those tracts. The team did the assessment using the USGS three-part form of mineral resource assessment, which is based on (1) mineral deposit and grade-tonnage models constructed from known deposits as analogs for undiscovered deposits, (2) delineation of permissive tracts based on geoscientific information, and (3) estimation of numbers of undiscovered deposits.

  12. Porphyry copper deposit model: Chapter B in Mineral deposit models for resource assessment (United States)

    Ayuso, Robert A.; Barton, Mark D.; Blakely, Richard J.; Bodnar, Robert J.; Dilles, John H.; Gray, Floyd; Graybeal, Fred T.; Mars, John L.; McPhee, Darcy K.; Seal, Robert R., II; Taylor, Ryan D.; Vikre, Peter G.; John, David A.


    This report contains a revised descriptive model of porphyry copper deposits (PCDs), the world's largest source (about 60 percent) and resource (about 65 percent) of copper and a major source of molybdenum, gold and silver. Despite relatively low grades (average 0.44 percent copper in 2008), PCDs have significant economic and societal impacts due to their large size (commonly hundreds of millions to billions of metric tons), long mine lives (decades), and high production rates (billions of kilograms of copper per year). The revised model describes the geotectonic setting of PCDs, and provides extensive regional- to deposit-scale descriptions and illustrations of geological, geochemical, geophysical, and geoenvironmental characteristics. Current genetic theories are reviewed and evaluated, knowledge gaps are identified, and a variety of exploration and assessment guides are presented. A summary is included for users seeking overviews of specific topics.

  13. Geology and porphyry copper-type alteration-mineralization of igneous rocks at the Christmas Mine, Gila County, Arizona (United States)

    Koski, Randolph A.


    The Christmas copper deposit, located in southern Gila County, Arizona, is part of the major porphyry copper province of southwestern North America. Although Christmas is known for skarn deposits in Paleozoic carbonate rocks, ore-grade porphyry-type copper mineralization also occurs in a composite granodioritic intrusive complex and adjacent mafic volcanic country rocks. This study considers the nature, distribution, and genesis of alteration-mineralization in the igneous rock environment at Christmas. At the southeast end of the Dripping Spring Mountains, the Pennsylvanian Naco Limestone is unconformably overlain by the Cretaceous Williamson Canyon Volcanics, a westward-thinning sequence of basaltic volcanic breccia and lava flows, and subordinate clastic sedimentary rocks. Paleozoic and Mesozoic strata are intruded by Laramide-age dikes, sills, and small stocks of hornblende andesite porphyry and hornblende rhyodacite porphyry, and the mineralized Christmas intrusive complex. Rocks of the elongate Christmas stock, intruded along an east-northeast-trending fracture zone, are grouped into early, veined quartz diorite (Dark Phase), biotite granodiorite porphyry (Light Phase), and granodiorite; and late, unveined dacite porphyry and granodiorite porphyry. Biotite rhyodacite porphyry dikes extending east and west from the vicinity of the stock are probably coeval with biotite granodiorite porphyry. Accumulated normal displacement of approximately 1 km along the northwest-trending Christmas-Joker fault system has juxtaposed contrasting levels (lower, intrusive-carbonate rock environment and upper, intrusive-volcanic rock environment) within the porphyry copper system. K-Ar age determinations and whole-rock chemical analyses of the major intrusive rock types indicate that Laramide calc-alkaline magmatism and ore deposition at Christmas evolved over an extended period from within the Late Cretaceous (~75-80 m.y. ago) to early Paleocene (~63-61 m.y. ago). The sequence of

  14. Porphyry copper assessment of East and Southeast Asia: Philippines, Taiwan (Republic of China), Republic of Korea (South Korea), and Japan: Chapter P in Global mineral resource assessment (United States)

    Hammarstrom, Jane M.; Bookstrom, Arthur A.; Demarr, Michael W.; Dicken, Connie L.; Ludington, Stephen; Robinson,, Gilpin R.; Zientek, Michael L.


    The U.S. Geological Survey collaborated with member countries of the Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP) on an assessment of the porphyry copper resources of East and Southeast Asia as part of a global mineral resource assessment. The assessment covers the Philippines in Southeast Asia, and the Republic of Korea (South Korea), Taiwan (Province of China), and Japan in East Asia. The Philippines host world class porphyry copper deposits, such as the Tampakan and Atlas deposits. No porphyry copper deposits have been discovered in the Republic of Korea (South Korea), Taiwan (Province of China), or Japan.

  15. Generation of porphyry copper deposits by gas-brine reaction in volcanic arcs (United States)

    Blundy, Jon; Mavrogenes, John; Tattitch, Brian; Sparks, Steve; Gilmer, Amy


    Porphyry copper deposits (PCDs) are characterised by a close spatial and temporal association with small, hypabyssal intrusions of silicic magmas in volcanic arcs. PCD formation requires elevated chlorine and water to concentrate copper in magmatic hypersaline liquids (or brines), and elevated sulphur to precipitate copper-rich sulphides. These twin requirements are hard to reconcile with experimental and petrological evidence that voluminous chlorine-rich, hydrous silicic magmas, of the variety favourable to copper enrichment, lack sufficient sulphur to precipitate directly the requisite quantities of sulphides. These features are, however, consistent with observations of active volcanic arcs whereby PCDs can be viewed as roots of dome volcanoes above shallow reservoirs where silicic magmas accumulate over long time spans. During protracted periods of dormancy metal-enriched dense brines accumulate in and above the silicic reservoir through slow, low-pressure degassing. Meanwhile cogenetic volatile-rich mafic magmas and their exsolved, sulphur and CO2-rich fluids accumulate in deeper reservoirs. Periodic destabilisation of these reservoirs leads to short-lived bursts of volcanism liberating sulphurous gases, which react with the shallow-stored brines to form copper-rich sulphides and acidic vapours. We test this hypothesis with a novel set of 'porphyry in a capsule' experiments designed to simulate low-pressure (1-2 kbar) interaction of basalt-derived, sulphur-rich gases with brine-saturated, copper-bearing, but sulphur-free, granite. Experiments were run at 720-850 ° C in cold-seal apparatus with basaltic andesite, loaded with H2O and S, situated below dacite, loaded with H2O, Cl and Cu. At run conditions both compositions are substantially degassed and crystallized. S-rich gas from the basaltic andesite ascends to react with Cu-rich brines exsolved from the dacite, Our experiments reveal the direct precipitation of copper-sulphide minerals, in vugs and veins

  16. 斑岩铜矿床研究进展%Review of Porphyry Copper Deposit

    Institute of Scientific and Technical Information of China (English)

    张云国; 周朝宪


    斑岩铜矿不但形成于环太平洋成矿域,还形成于特提斯成矿域和中亚成矿域(古亚洲洋成矿域)。成矿物质来源于深部,经过“洋壳一地幔熔岩流”、“原始岩浆”、“浅部富矿岩浆”和“岩浆结晶一成矿”4个阶段,其中在“原始弧岩浆”阶段,通过MASH过程,有大量成矿物质和能量的聚集。成矿流体为富H2O、高温、高压、高盐度、强氧化性、高氧逸度的富矿气液相流体,这些特点有利于成矿物质在岩浆一热液分离过程中向流体富集,并以氯络合物的形式运移。随着成矿流体的上侵,温度和压力的降低是成矿物质沉淀的主要影响因素。磁铁矿的结晶为成矿流体提供了大量的S2-离子,也是导致成矿物质沉淀的主要因素。斑岩型蚀变带从里向外为石英内核、钾化带、SCC带和泥化带,铜矿化主要发育在矿化带外围以及SCC带。目前,斑岩铜矿成矿模型主要有经典模型、系统模型和多阶段叠加模型。%Porphyry copper deposit as the largest source of Cu is one of the most important deposits in the world. Porphyry Copper Deposit not only occured in Circum-Pacific ore-forming region, but also oceured in Tethys ore-forming region and Middle-Asian(Paleo-Asian Oceanic) ore-forming region. The mineralization materials de- rived from the deep. Porphyry forms through four stages: "Oceanic Crust-Mantle Lava Flow"," Original Magma", "Shallow Ore Magma"," Crystallization of Magma-Minerali- zation". In the stage of "Original Magma", much met- allogenic materials and energy gather through the process of "MASH". Ore-forming fluids are high-grade fliuds of gas-liquid phase, which are of fluid-rich, high temperature, high pressure, high salinity, strong oxidizing, high ox- ygen fugacity. The characteristics of ore-torming fluids are favorable tbr metallogenic materials to gather from mag- mas to fluids in the

  17. Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes. (United States)

    Weis, P; Driesner, T; Heinrich, C A


    Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production.

  18. Characteristics and evolution of ore-forming fluids of the Chongjiang copper deposit in the Gangdise porphyry copper belt, Tibet

    Institute of Scientific and Technical Information of China (English)

    Yuling Xie; Jiuhua Xu; Guangming Li; Zhiming Yang; Longsheng Yi


    Petrography, microthermometry, and scanning electron microscope/energy dispersive spectrometer (SEM/EDS) studies were performed on the fluid inclusions in the ore-bearing quartz veins and quartz phenocrysts in the porphyry of the Chongjiang porphyry copper deposit. The analyses of the fluid inclusions indicate that the ore-forming fluids were exsolved from magma. They are near-saturated, supercritical, rich in volatile constituents, and have the capture temperature of 362-389°C and salinities of 17.7wt%-18.9wt% NaCl eq. With the decreasing of temperature and pressure, the supercritical fluids were separated into a low salinity vapor phase and a high salinity liquid phase. During quartz-sericitization, the high salinity fluid boiled and separated into a low salinity vapor phase and a high salinity liquid phase. The high salinity inclusions that formed in the boiling process had daughter mineral melting temperatures higher than the homogenization temperatures of the vapor and liquid phases. The late fluids that are responsible for argillization are of lower temperature and salinity.

  19. Porphyry copper assessment of Central America and the Caribbean Basin: Chapter I in Global mineral resource assessment (United States)

    Gray, Floyd; Hammarstrom, Jane M.; Ludington, Stephen; Zürcher, Lukas; Nelson, Carl E.; Robinson,, Gilpin R.; Miller, Robert J.; Moring, Barry C.


    Mineral resource assessments provide a synthesis of available information about distributions of mineral deposits in the Earth’s crust. The U.S. Geological Survey prepared a probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in Central America and the Caribbean Basin in collaboration with geoscientists from academia and the minerals industry. The purpose of the study was to (1) delineate permissive areas (tracts) for undiscovered porphyry copper deposits within 1 kilometer of the surface at a scale of 1:1,000,000; (2) provide a database of known porphyry copper deposits and significant prospects; (3) estimate numbers of undiscovered deposits within the permissive tracts; and (4) provide probabilistic estimates of amounts of copper, molybdenum, gold, and silver that could be contained in undiscovered deposits. The assessment was done using a three-part mineral resource assessment based on established mineral deposit models. Permissive tracts were delineated based primarily on distributions of mapped igneous rocks related to magmatic arcs that formed in tectonic settings associated with convergent plate margins. Five permissive tracts were delineated: the Early Cretaceous through Eocene Santiago tract, the Late Cretaceous through Oligocene Chortis tract, the Paleocene through Oligocene Darién tract, the Miocene and Pliocene Cocos tract, and the Eocene to Holocene Lesser Antilles tract. These tracts range in size from about 3,000 to about 204,000 square kilometers.

  20. Speciation and leachability of copper in mine tailings from porphyry copper mining

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Yianatos, Juan B; Ottosen, Lisbeth M.


    Mine tailing from the El Teniente-Codelco copper mine situated in VI Region of Chile was analysed in order to evaluate the mobility and speciation of copper in the solid material. Mine tailing was sampled after the rougher flotation circuits, and the copper content was measured to 1150mgkg^-^1 dry...... matter. This tailing was segmented into fractions of different size intervals: 0-38, 38-45, 45-53, 53-75, 75-106, 106-150, 150-212, and >212@mm, respectively. Copper content determination, sequential chemical extraction, and desorption experiments were carried out for each size interval in order...... to evaluate the speciation of copper. It was found that the particles of smallest size contained 50-60% weak acid leachable copper, whereas only 32% of the copper found in largest particles could be leached in weak acid. Copper oxides and carbonates were the dominating species in the smaller particles...

  1. A review of the geological characteristics and geodynamic setting of Late Paleozoic porphyry copper deposits in the Junggar region, Xinjiang Uygur Autonomous Region, Northwest China (United States)

    Yang, Fuquan; Mao, Jingwen; Pirajno, Franco; Yan, Shenghao; Liu, Guoren; Zhou, Gang; Zhang, Zhixin; Liu, Feng; Geng, Xinxia; Guo, Chunli


    In this review, we describe the geological characteristics of porphyry copper deposits in Junggar region, Xinjiang, and place these into their metallogenic-tectonic context. These porphyry copper deposits are mainly found in four metallogenic belts: (1) a Late Silurian to Early Devonian Cu-Mo metallogenic belt in the Qiongheba area; (2) the Late Devonian Kalaxiange'er Cu metallogenic belt; (3) the Early Carboniferous Xilekuduke-Suoerkuduke porphyry-skarn Cu-Mo metallogenic belt; and (4) the Late Carboniferous Baogutu porphyry Cu metallogenic belt. The ages of mineralization can be divided into three broad intervals: copper deposits range mainly from 300 to 180 °C. Salinity ranges from 0.5 to 21.7 wt.% NaCl equiv and 28.9 to 66.76 wt.% NaCl equiv. Ore-forming fluids in the Baogutu and Yunyingshan deposits in the Baogutu and Qiongheba belts, were mainly derived from magmatic fluids, whereas those in the Halasu, Yulekenhalasu and Xilekuduke deposits in the Kalaxiange'er and Xilekuduke-Suoerkuduke belts were mainly derived from magmatic fluids, with some contributions from meteoric water. Sulfur isotope compositions of some porphyry copper deposits cluster around 0‰, indicating that the sulfur was probably derived from mantle-related magmas. The ore-forming processes in all porphyry copper deposits are closely related to the emplacement of intermediate, intermediate-felsic and felsic porphyry intrusions. Porphyry copper deposits in Junggar region developed in a range of tectonic regimes including continental arc, ocean island arc and post collisional settings.

  2. The partitioning of copper among selected phases of geologic media of two porphyry copper districts, Puerto Rico (United States)

    Learned, R.E.; Chao, T.T.; Sanzolone, R.F.


    In experiments designed to determine the manner in which copper is partitioned among selected phases that constitute geologic media, we have applied the five-step sequential extraction procedure of Chao and Theobald to the analysis of drill core, soils, and stream sediments of the Rio Vivi and Rio Tanama porphyry copper districts of Puerto Rico. The extraction procedure affords a convenient means of determining the trace-metal content of the following fractions: (1) Mn oxides and "reactive" Fe oxides; (2) "amorphous" Fe oxides; (3) "crystalline" Fe oxides; (4) sulfides and magnetite; and (5) silicates. An additional extraction between steps (1) and (2) was performed to determine organic-related copper in stream sediments. The experimental results indicate that apportionment of copper among phases constituting geologic media is a function of geochemical environment. Distinctive partitioning patterns were derived from the analysis of drill core from each of three geochemical zones: (a) the supergene zone of oxidation; (b) the supergene zone of enrichment; and (c) the hypogene zone; and similarly, from the analysis of; (d) soils on a weakly leached capping; (e) soils on a strongly leached capping; and (f) active stream sediment. The experimental results also show that geochemical contrasts (anomaly-to-background ratios) vary widely among the five fractions of each sampling medium investigated, and that at least one fraction of each medium provides substantially stronger contrast than does the bulk medium. Fraction (1) provides optimal contrast for stream sediments of the district; fraction (2) provides optimal contrast for soils on a weakly leached capping; fraction (3) provides optimal contrast for soils on a strongly leached capping. Selective extraction procedures appear to have important applications to the orientation and interpretive stages of geochemical exploration. Further investigation and testing of a similar nature are recommended. ?? 1981.

  3. Uplift and submarine formation of some Melanesian porphyry copper deposits: Stable isotope evidence (United States)

    Chivas, A.R.; O'Neil, J.R.; Katchan, G.


    Hydrogen and oxygen isotope analyses of sericites and kaolinites from four young porphyry copper deposits (Ok Tedi (1.2 Ma) and Yandera (6.5 Ma), Papua New Guinea; Koloula (1.5 Ma), Solomon Islands; and Waisoi (ocean water. For Ok Tedi, the non-magmatic component was a meteoric water with an isotopic composition different from that of the present meteoric water in the region. The isotopic signature of the former meteoric water is consistent with a surface elevation of 200 m a.s.l. or less at the time of mineralization. The deposit was later exposed and supergene kaolinitization commenced at approximately 1200 m a.s.l. Uplift and erosion has continued to the present at which time the elevation of the exposed deposit is 1800 m a.s.l. This rate of uplift is consistent with that known from other geological evidence. If the rate of uplift were approximately constant during the last 1.2 Ma, the age of supergene enrichment can be dated at approximately 0.4 Ma B.P. Similarly, influx of meteoric water at Yandera occurred when the ground surface above the deposit was at an elevation of approximately 600 m a.s.l. The deposit's present elevation is 1600 m a.s.l. In this case a total uplift of approximately 2.2 km is indicated, with removal of 1.2 km of overburden by erosion. ?? 1984.

  4. Lead and zinc geochemical behavior based on geological characteristics in Parkam Porphyry Copper System, Kerman, Iran

    Institute of Scientific and Technical Information of China (English)

    Seyyed; Saeed; Ghannadpour; Ardeshir; Hezarkhani


    Parkam(Sarah) porphyry system is located on the metallogenic belt of Kerman, Iran. Due to existence of some copper-rich resources in this region, finding out the exact statistical characteristics such as distribution of data population, mean, variance and data population behavior of elements like Cu, Mo, Pb and Zn is necessary for interpreting their geological behavior. For this reason, precise calculation of statistical characteristics of Pb and Zn grade datasets was performed and results were interpreted geologically. The natures of Pb and Zn distributions were initially identified and their distributions were normalized through statistical treatment. Subsequently, the variograms were calculated for each exploration borehole and show that both Pb and Zn geochemical variates are spatially correlated. According to the similarity of the behavior of Pb and Zn in these calculations, it is decided to measure their exact behavior applying K-means clustering method. K-means clustering results show that the Zn grade varies linearly relative to that of Pb values and their behavior is similar. Based on the geochemical behavior similarity of Pb and Zn, throughout the pervasive secondary hydrothermal activity, they are remobilized in the similar manner, from the deep to the shallow levels of the mineralization zones. However, statistical analysis suggests that hydrothermal activity associated with secondary waters in Parkam is effective in remobilizing and enriching both Pb and Zn since they have similar geochemical characteristics. However, the process does not result in generation of economic concentrations.

  5. The mass balance calculation of hydrothermal alteration in Sarcheshmeh porphyry copper deposit

    Directory of Open Access Journals (Sweden)

    Mohammad Maanijou


    Full Text Available Sarcheshmeh porphyry copper deposit is located 65 km southwest of Rafsanjan in Kerman province. The Sarcheshmeh deposit belongs to the southeastern part of Urumieh-Dokhtar magmatic assemblage (i.e., Dehaj-Sarduyeh zone. Intrusion of Sarcheshmeh granodiorite stock in faulted and thrusted early-Tertiary volcano-sedimentary deposits, led to mineralization in Miocene. In this research, the mass changes and element mobilities during hydrothermal process of potassic alteration were studied relative to fresh rock from the deeper parts of the plutonic body, phyllic relative to potassic, argillic relative to phyllic and propylitic alteration relative to fresh andesites surrounding the deposit. In the potassic zone, enrichment in Fe2O3 and K2O is so clear, because of increasing Fe coming from biotite alteration and presence of K-feldspar, respectively. Copper and molybdenum enrichments resulted from presence of chalcopyrite, bornite and molybdenite mineralization in this zone. Enrichment of SiO2 and depletion of CaO, MgO, Na2O and K2O in the phyllic zone resulted from leaching of sodium, calcium and magnesium from the aluminosilicate rocks and alteration of K-feldspar to sericite and quartz. In the argillic zone, Al2O3, CaO, MgO, Na2O and MnO have also been enriched in which increasing Al2O3 may be from kaolinite and illite formation. Also, enrichment in SiO2, Al2O3 and CaO in propylitic alteration zone can be attributed to the formation of chlorite, epidote and calcite as indicative minerals of this zone.

  6. Fluid inclusion evidence for hydrothermal fluid evolution in the Darreh-Zar porphyry copper deposit, Iran (United States)

    Nateghi, Arash; Hezarkhani, Ardeshir


    The Darreh-Zar porphyry copper deposit is associated with a quartz monzonitic-granodioritic-porphyritic stock hosted by an Eocene volcanic sedimentary complex in which magmatic hydrothermal fluids were introduced and formed veins and alteration. Within the deepest quartz-rich and chalcopyrite-poor group A veins, LVHS2 inclusions trapped high salinity, high temperature aqueous fluids exsolved directly from a relatively shallow magma (0.5 kbar). These late fluids were enriched in NaCl and reached halite saturation as a result of the low pressure of magma crystallization and fluid exsolution. These fluids extracted Cu from the crystallizing melt and transported it to the hydrothermal system. As a result of ascent, the temperature and pressure of these fluids decreased from 600 to 415 °C, and approximately 500-315 bars. At these conditions, K-feldspar and biotite were stabilized. Type A veins were formed at a depth of ∼1.2 km under conditions of lithostatic pressure and abrupt cooling. Upon cooling and decompressing, the fluid intersected with the liquid-vapor field resulting in separation of immiscible liquid and vapor. This stage was recorded by formation of LVHS1, LVHS3 and VL inclusions. These immiscible fluids formed chalcopyrite-pyrite-quartz veins with sericitic alteration envelopes (B veins) under the lithostatic-hydrostatic pressure regime at temperatures between 415 and 355 °C at 1.3 km below the paleowater table. As the fluids ascended, copper contents decreased and these fluids were diluted by mixing with the low salinity-external fluid. Therefore, pyrite-dominated quartz veins were formed in purely hydrostatic conditions in which pressure decreased from 125 bars to 54 bars and temperature decreased from 355 to 298 °C. During the magmatic-hydrothermal evolution, the composition and P-T regime changed drastically and caused various types of veins and alterations. The abundance of chalcopyrite precipitation in group B veins suggests that boiling and

  7. Remote sensing evaluation of the regional chemistry and element dispersion of porphyry copper deposits in the Silver Bell Mountains, Arizona (United States)

    Jaramillo-Nieves, Lorna G.

    Porphyry copper deposits in southeastern Arizona belong to a cluster of 38 mineralized centers covering a region extending from northern Mexico to western New Mexico and southern Arizona. Presently, some of these deposits are being actively mined and the rest are prospects or abandoned mining sites. As a result of the large number of porphyry copper deposits in this region, research on the interaction between mineralized centers and the environment is important; in particular, the dispersion characteristics of acid-generating metal-enriched materials at the shallow alluvial margins of these centers. The present research uses remote sensing techniques, groundwater chemistry, trace element, and mineralogical analysis to characterize dispersion chemistry surrounding porphyry copper deposits in the Silver Bell Mountains. Hyperspectral imagery obtained by the Airborne Visible/Infrared Spectrometer and HyMap are used to map supergene minerals by analyzing their spectral profiles in the visible and short wave infrared regions of the electromagnetic spectrum. Reflectance profiles are characteristic of each mineral and shifts in absorption features within one mineral are a result of differences in cation content. Image reflectance profiles are compared with stream sediment mineralogy and reflectance spectral profiles to better outline concentrations of Fe, S, K, Na, Ca, Mg, Cu, and Al. In addition, groundwater modeling in the Silver Bell Mountains is considered for various flow paths within shallow aquifers in the region and compared to actual groundwater chemistry and surface lithology. The Silver Bell Mountains serve as a case study for element mobility and concentration distribution in other areas where undisturbed deposits, historic and present-day excavation activity occurs, where semi-arid climate and a deep vadose zone are variables that influence element mobility and concentration. Results obtained from hyperspectral image processing indicate the possible enrichment

  8. From a long-lived upper-crustal magma chamber to rapid porphyry copper emplacement: Reading the geochemistry of zircon crystals at Bajo de la Alumbrera (NW Argentina) (United States)

    Buret, Yannick; von Quadt, Albrecht; Heinrich, Christoph; Selby, David; Wälle, Markus; Peytcheva, Irena


    The formation of world class porphyry copper deposits reflect magmatic processes that take place in a deeper and much larger underlying magmatic system, which provides the source of porphyry magmas, as well as metal and sulphur-charged mineralising fluids. Reading the geochemical record of this large magmatic source region, as well as constraining the time-scales for creating a much smaller porphyry copper deposit, are critical in order to fully understand and quantify the processes that lead to metal concentration within these valuable mineral deposits. This study focuses on the Bajo de la Alumbrera porphyry copper deposit in Northwest Argentina. The deposit is centred on a dacitic porphyry intrusive stock that was mineralised by several pulses of porphyry magma emplacement and hydrothermal fluid injections. To constrain the duration of ore formation, we dated zircons from four porphyry intrusions, including pre-, syn- and post-mineralisation porphyries based on intersection relations between successive intrusion and vein generations, using high precision CA-ID-TIMS. Based on the youngest assemblages of zircon grains, which overlap within analytical error, all four intrusions were emplaced within 29 ka, which places an upper limit on the total duration of hydrothermal mineralisation. Re/Os dating of hydrothermal molybdenite fully overlaps with this high-precision age bracket. However, all four porphyries contain zircon antecrysts which record protracted zircon crystallisation during the ∼200 ka preceding the emplacement of the porphyries. Zircon trace element variations, Ti-in-zircon temperatures, and Hf isotopic compositions indicate that the four porphyry magmas record a common geochemical and thermal history, and that the four intrusions were derived from the same upper-crustal magma chamber. Trace element zoning within single zircon crystals confirms a fractional crystallisation trend dominated by titanite and apatite crystallisation. However, zircon

  9. Ridge subduction and porphyry copper-gold mineralization:An overview

    Institute of Scientific and Technical Information of China (English)


    Many large porphyry Cu-Au deposits are connected to adakitic rocks known to be closely associated with ridge subduction. For example, there are several subducting ridges along the east Pacific margin, e.g., in Chile, Peru, and South America, most of which are associated with large porphyry Cu-Au deposits. In contrast, there are much fewer ridge subductions on the west Pacific margin and porphyry Cu-Au deposits are much less there, both in terms of tonnage and the number of deposits. Given that Cu and Au are moderately incompatible elements, oceanic crust has much higher Cu-Au concentrations than the mantle and the continental crust, and thus slab melts with their diagnostic adakitic chemistry have systematically higher Cu and Au, which is favorable for mineralization. Considering the geotherm of subducting slabs in the Phanerozoic, ridge subduction is the most favorable tectonic setting for this. Therefore, slab melting is the likely link in the spatial association between ridge subduction and Cu-Au deposits. Geochemical signatures of slab melting and hence maybe ridge subduction in less eroded regions in eastern China, the central Asian orogenic belt etc. may indicate important exploration targets for large porphyry Cu-Au deposits.

  10. Ore-forming fluid constraints on illite crystallinity (IC) at Dexing porphyry copper deposit, Jiangxi Province

    Institute of Scientific and Technical Information of China (English)

    JIN; Zhangdong


    [1]uatier, M. D., Peacor, D. R., O’Neil, J. R., Smectite-illite transition in Barbados accretionary wedge sediments: TEM and AEM evidence for dissolution/crystallization at low temperature, Clays and Clay Minerals, 1992, 40(1): 65.[2]Eberl, D., Hower, J., Kinetics of illite formation, Geological Society of America Bulletin, 1976, 9: 1326[3]Elliott, W. C., Matisoff, G., Evaluation of kinetic models for smectite to illite transformation, Clays and Clay Minerals, 1996, 44(1): 77.[4]Ji Junfeng, Browne, P. R. L., Liu Yingjun et al., Kinetic model for the smectite to illite transformation in active geothermal system, Chinese Science Bulletin (in Chinese), 1997, 42 (21): 2313[5]Pollastro, R. M., Considerations and applications of the illite/smectite geothermometer in hydrocarbonbearing rocks of Miocene to Mississippian age, Clays and Clay Minerals, 1993, 41(1): 119[6]Harvey, C. C., Browne, P. R. L., Mixed-layer clay geothermometry in the Wairakei geothermal field, New Zealand, Clays and Clay Minerals, 1991, 39(3): 614[7]Whitney, G., Role of water in the smectite-to-illite reaction, Clays and Clay Minerals, 1990, 38 (2): 343.[8]Inoue, A., Kitagawa, R., Morphological characteristics of illitic clay minerals from a hydrothermal system, American Mineralogist, 1994, 79: 700.[9]Velde, B., Vasseur, G., Estimation of the diagenetic smectite to illite in time-temperature space, American Mineralogist, 1992, 77: 967.[10]hu Xun, Huang Chongke, Rui Zongyao et al., Dexing Porphyry Copper Deposit (in Chinese), Beijing: Geological Publishing House, 1983.[11]Kisch, H. J., Illite crystallinity: recommendation on sample preparation, X-ray diffraction settings and interlaboratory samples, Journal of Metamorphic Geology, 1991, 9: 665.[12]Eberl, D. D., Velde, B., Beyond the Kübler Index, Clay Minerals, 1989, 24(3): 571.[13]Srodon, J., Eberl, D. D., Illite. Micas, Reviews in Mineralogy (ed. Bailey, S. W.), 1984, 13: 495.[14]Yao, Y. C

  11. A predictive model for the transport of copper by HCl-bearing water vapour in ore-forming magmatic-hydrothermal systems: Implications for copper porphyry ore formation (United States)

    Migdisov, Art. A.; Bychkov, A. Yu.; Williams-Jones, A. E.; van Hinsberg, V. J.


    divalent copper dichloride (CuCl2). The model developed in this study was used to evaluate the solubility of chalcopyrite in HCl-bearing, low density aqueous fluids for temperatures ranging between 300 and 800 °C. This evaluation showed that, even for a relatively modest proportion of HCl (0.5 vol%), the concentration of copper in low-density fluids in equilibrium with this mineral can reach thousands of ppm at temperatures between 550 and 700 °C and fO2 conditions similar to those of porphyry copper ore-forming systems.

  12. HRTEM/AEM study of trace metal behavior, sheet silicate reactions, and fluid/solid mass balances in porphyry copper hydrothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Veblen, D.R.; Ilton, E.S.


    Transmission electron microscopy has been used to investigate copper (Cu) incorporation into silicates and alteration reactions in porphyry copper deposits. High Cu in biotites results from submicroscopic inclusions of native Cu. The incorporation of Cu in low-temperature alteration lamellae suggests that Cu enrichment occurs during weathering, rather than during the hydrothermal event. Drill core from Cyprus Casa Grande, Arizona, shows systematic variation of Cu in sheet silicates as a function of depth in the weathering column. The aims of the present project are to apply the powerful techniques of transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and analytical electron microscopy (AEM) to understanding the geochemical processes in porphyry copper systems at the near-atomic scale. Our primary goals are to characterize the structural state of anomalously high Cu in silicates, determine the timing and conditions of Cu enrichment in silicates such as biotite, and use these data to suggest how base metals are released and subsequently immobilized under hydrothermal or weathering conditions; and to determine the submicroscopic, atomic-level reaction mechanisms responsible for silicate alteration in porphyry-copper hydrothermal systems, which will allow us to determine reaction stoichiometries and hence mass balances between minerals and hydrothermal fluid. 19 refs., 7 figs., 3 tabs.

  13. Petrochemistry of igneous rocks of the California-Vetas mining district, Santander, Colombia: Implications for northern Andean tectonics and porphyry Cu (-Mo, Au) metallogeny (United States)

    Bissig, Thomas; Mantilla Figueroa, Luis Carlos; Hart, Craig J. R.


    Porphyry Mo and Cu mineralization in the California-Vetas mining district is contemporaneous with 10.9 to 8.4 Ma granodiorite porphyry stocks and overprinted by Au-Ag mineralization of epithermal affinity. Mineralization is hosted by Grenvillian aged paragneisses (Bucaramanga Gneiss of the Santander Massif) and late Triassic to early Jurassic granitic rocks. All intrusive rocks are high-K calc-alkaline. Late Triassic to early Jurassic rocks include peraluminous granites with more than 70 wt.% SiO2 as well as metaluminous diorites, tonalites and granodiorites with SiO2 between 54.9 and 60.4 wt.%. Late Miocene rocks are weakly peraluminous granodiorite porphyries with SiO2 between 61 and 67 wt.% SiO2. Late Miocene rocks share some characteristics with adakite-like rocks which are widely associated with porphyry and epithermal style mineralization elsewhere in the Andes. They have high Ba (930 to 1500 ppm) and high Ba/La (28 to 50), high Sr (850 to 1100 ppm) and Sr/Y (48-78) and depleted middle rare earth elements (MREE) compared to the Mesozoic granites, which have 400 to 700 ppm Ba (Ba/La 14 to 25) and 80 to 150 ppm Sr (Sr/Y 2.5 to 14), and Mesozoic diorites and tonalites, which have ~ 900 to 1200 ppm Ba (Ba/La 20 to 32) and ~ 610 to 750 ppm Sr (Sr/Y 22 to 25). Miocene granodiorite porphyries, in contrast to Mesozoic intrusive rocks have only weak negative Eu anomalies. The Miocene rocks have 87Sr/86Sr ratios of 0.7052 to 0.7067 and εNd of - 1.9 to - 5.4 and are significantly more isotopically primitive than all other rocks in the study area including the Mesozoic diorites to tonalites (87Sr/86Sr = 0.7082 and 0.7092; εNd = - 6.7 and - 7.2), granites (87Sr/86Sr = 0.730 (n = 2); εNd = - 8.2 and - 8.3) and Bucaramanga Gneiss (0.718 to 0.743; εNd = - 10.8 to - 14.1). Lead isotope data are broadly consistent with the Sr and Nd isotope data and the Miocene porphyries have the lowest 207Pb/204Pb ratios but overlap with the Mesozoic diorites to tonalites in their 206Pb

  14. Geochronology and isotope geochemistry of the Baogutu porphyry copper deposit in the West Junggar region, Xinjiang, China (United States)

    Shen, Ping; Shen, Yuanchao; Pan, Hongdi; Li, Xian-hua; Dong, Lianhui; Wang, Jingbin; Zhu, Heping; Dai, Huawu; Guan, Weina


    The Baogutu copper deposit, a newly-discovered middle-sized porphyry copper deposit, is located in the West Junggar region of Xinjiang, NW China. Baogutu is associated with a Late Carboniferous intrusive complex that was emplaced into Lower Carboniferous volcano-sedimentary strata. The intrusive complex comprises main-stage diorites and minor late-stage diorite porphyries. Their intrusive activity occurred in 313.0 ± 2.2 Ma to 312.3 ± 2.2 Ma based on U-Pb zircon SIMS analyses. Molybdenite separated from ore-bearing quartz veins yields Re-Os model ages from 309.4 ± 4.4 Ma to 314.1 ± 4.5 Ma with a weighted mean age of 312.4 ± 1.8 Ma. Biotites, separated from fresh diorite and hydrothermal breccias in main-stage diorites, yield 40Ar/39Ar plateau ages of 308.26 ± 1.88 and 305.69 ± 1.76 Ma, respectively. These dates obtained from three independent dating techniques constrain the ore-forming age of the Baogutu deposit. Stable isotopes (H, O, S) and radiogenic isotope (Pb) have been used to discriminate the sources of the ore-forming fluid at Baogutu. The δ18O (1.14-1.74‰) and δD (-74‰ to -98‰) data indicate that the water of the ore-forming fluids was derived from magmatic water. The δ34S values (-0.24‰ to +0.4‰) show that the sulfur isotope composition of the ore fluids is characterized by magma sulfur. Lead isotope compositions (206Pb/204Pb = 17.92-18.89, 207Pb/204Pb = 15.45-15.62, 208Pb/204Pb = 37.68-38.36) indicate that the lead of the ore fluids is derived from the mantle. These data confirm the occurrence of a Cu-Au-Mo mineralizing event at Late Carboniferous in the Baogutu region and the ore-forming fluids are mainly derived from the mantle. The event is inferred to be associated with Late Carboniferous Junggar oceanic crust subduction.

  15. Temporal Evolution of Volcanic and Plutonic Magmas Related to Porphyry Copper Ores Based on Zircon Geochemistry (United States)

    Dilles, J. H.; Lee, R. G.; Wooden, J. L.; Koleszar, A. M.


    Porphyry Cu (Mo-Au) and epithermal Au-Ag ores are globally associated with shallow hydrous, strongly oxidized, and sulfur-rich arc intrusions. In many localities, long-lived magmatism includes evolution from early andesitic volcanic (v) and plutonic (p) rocks to later dacitic or rhyolitic compositions dominated by plutons. We compare zircon compositions from three igneous suites with different time spans: Yerington, USA (1 m.y., p>v), El Salvador, Chile (4 m.y., p>v), and Yanacocha, Peru (6 m.y., v>p). At Yerington granite dikes and ores formed in one event, at ES in 2 to 3 events spanning 3 m.y., and at Yanacocha in 6 events spanning 5 m.y. At both ES and Yanacocha, high-Al amphiboles likely crystallized at high temperature in the mid-crust and attest to deep magmas that periodically recharged the shallow chambers. At Yanacocha, these amphiboles contain anhydrite inclusions that require magmas were sulfur-rich and strongly oxidized (~NNO+2). The Ti-in-zircon geothermometer provides estimates of 920º to 620º C for zircon crystallization, and records both core to rim cooling and locally high temperature rim overgrowths. Ore-related silicic porphyries yield near-solidus crystallization temperatures of 750-650°C consistent with low zircon saturation temperatures. The latter zircons have large positive Ce/Ce* and small negative Eu/Eu*≥0.4 anomalies attesting to strongly oxidized conditions (Ballard et al., 2001), which we propose result from crystallization and SO2 loss to the magmatic-hydrothermal ore fluid (Dilles et al., 2015). The Hf, REE, Y, U, and Th contents of zircons are diverse in the magma suites, and Th/U vs Yb/Gd plots suggest a dominant role of crystal fractionation with lesser roles for both crustal contamination and mixing with high temperature deep-sourced mafic magma. Ce/Sm vs Yb/Gd plots suggest that magma REE contents at <900°C are dominated by early crystallization of hornblende and apatite, and late crystallization (~<780°C) of titanite

  16. Mapping hydrothermal alteration using aircraft VNIR scanners at the Rosemont porphyry copper deposit. [Visible-Near Infrared (United States)

    Sadowski, R. M.; Abrams, M. J.


    Two Visible-Near Infrared (VNIR) scanners, the NS-001 and the M2S, were flown over the Rosemont porphyry copper deposit as part of the NASA/JPL/GEOSAT test site program. This program was established to determine the feasibility and limitations of mapping hydrothermal alteration with multispectral scanners. Data from the NS-001 at 0.83 and 2.2 microns were used to identify Fe(3+) and OH enriched outcrops. These areas were then correlated with three alteration assemblages. The first correlation, hematite-epidote, was the most obvious and appeared as a strong ferric iron signature associated with hematite stained Cretaceous arkoses and andesites. The second correlation, qtz-sericite, showed a combined ferric-hydroxyl signature for a phyllicly altered quartz monzonite. The third correlation, skarn, was identified only after a review of calc-silicate mineral VNIR spectra. Altered limestones that outcrop west of the deposit have a similar ferric iron-hydroxyl signature as the quartz-sericite altered quartz monzonite. This skarn signature has been interpreted to indicate the presence of andradite, hydro-grossularite and idocrase. Data from the second scanner, M2S, was used to search for variation in ferric iron mineral type. Resulting imagery data indicated that hematite was the dominant ferric iron mineral present in the Rosemont area.

  17. Economic filters for evaluating porphyry copper deposit resource assessments using grade-tonnage deposit models, with examples from the U.S. Geological Survey global mineral resource assessment: Chapter H in Global mineral resource assessment (United States)

    Robinson,, Gilpin R.; Menzie, W. David


    An analysis of the amount and location of undiscovered mineral resources that are likely to be economically recoverable is important for assessing the long-term adequacy and availability of mineral supplies. This requires an economic evaluation of estimates of undiscovered resources generated by traditional resource assessments (Singer and Menzie, 2010). In this study, simplified engineering cost models were used to estimate the economic fraction of resources contained in undiscovered porphyry copper deposits, predicted in a global assessment of copper resources. The cost models of Camm (1991) were updated with a cost index to reflect increases in mining and milling costs since 1989. The updated cost models were used to perform an economic analysis of undiscovered resources estimated in porphyry copper deposits in six tracts located in North America. The assessment estimated undiscovered porphyry copper deposits within 1 kilometer of the land surface in three depth intervals.

  18. Bio-Remediation of Acid Mine Drainage in the Sarcheshmeh Porphyry Copper Mine by Fungi: Batch and Fixed Bed Process

    Directory of Open Access Journals (Sweden)

    Hanieh Soleimanifar


    Full Text Available Acid mine drainage (AMD containing high concentrations of iron and sulphate, low pH and variableconcentrations of heavy metals leads to many environmental problems. The concentrations of Cu and Mnare high in the AMD of the Sarcheshmeh porphyry copper mine, Kerman province, south of Iran. In thisstudy, the bio-remediation of Cu and Mn ions from acid mine drainage was investigated using two nativefungi called Aspergillus niger and Phanerochaete chrysosporium which were extracted from the soil andsediment samples of the Shour River at the Sarcheshmeh mine. The live fungi was first harvested andthen killed by boiling in 0.5 N NaOH solution. The biomass was finally dried at 60 C for 24 h andpowdered. The optimum biosorption parameters including pH, temperature, the amount of biosorbent andcontact time were determined in a batch system. The optimum pH varied between 5 and 6. It was foundthat the biosorption process increased with an increase in temperature and the amount of biosorbent.Biosorption data were attempted by Langmuir and Freundlich isotherm models and showed a good match.Kinetic studies were also carried out in the present study. The results show that the second-order kineticsmodel fits well the experimental data. The biosorption experiments were further investigated with acontinuous system to compare the biosorption capacities of two systems. The results show thatbiosorption process using a continuous system increases efficiency up to 99%. A desorption process waseventually performed in order to recover Copper and Manganese ions. This process was successful andfungi could be used again.

  19. Porphyry copper assessment of the Central Asian Orogenic Belt and eastern Tethysides: China, Mongolia, Russia, Pakistan, Kazakhstan, Tajikistan, and India: Chapter X in Global mineral resource assessment (United States)

    Mihalasky, Mark J.; Ludington, Stephen; Hammarstrom, Jane M.; Alexeiev, Dmitriy V.; Frost, Thomas P.; Light, Thomas D.; Robinson,, Gilpin R.; Briggs, Deborah A.; Wallis, John C.; Miller, Robert J.; Bookstrom, Arthur A.; Panteleyev, Andre; Chitalin, Andre; Seltmann, Reimar; Guangsheng, Yan; Changyun, Lian; Jingwen, Mao; Jinyi, Li; Keyan, Xiao; Ruizhao, Qiu; Jianbao, Shao; Gangyi, Shai; Yuliang, Du


    The U.S. Geological Survey collaborated with international colleagues to assess undiscovered resources in porphyry copper deposits in the Central Asian Orogenic Belt and eastern Tethysides. These areas host 20 known porphyry copper deposits, including the world class Oyu Tolgoi deposit in Mongolia that was discovered in the late 1990s. The study area covers major parts of the world’s largest orogenic systems. The Central Asian Orogenic Belt is a collage of amalgamated Precambrian through Mesozoic terranes that extends from the Ural Mountains in the west nearly to the Pacific Coast of Asia in the east and records the evolution and final closure of the Paleo-Asian Ocean in Permian time. The eastern Tethysides, the orogenic belt to the south of the Central Asian Orogenic Belt, records the evolution of another ancient ocean system, the Tethys Ocean. The evolution of these orogenic belts involved magmatism associated with a variety of geologic settings appropriate for formation of porphyry copper deposits, including subduction-related island arcs, continental arcs, and collisional and postconvergent settings. The original settings are difficult to trace because the arcs have been complexly deformed and dismembered by younger tectonic events. Twelve mineral resource assessment tracts were delineated to be permissive for the occurrence of porphyry copper deposits based on mapped and inferred subsurface distributions of igneous rocks of specific age ranges and compositions. These include (1) nine Paleozoic tracts in the Central Asian Orogenic Belt, which range in area from about 60,000 to 800,000 square kilometers (km2); (2) a complex area of about 400,000 km2 on the northern margin of the Tethysides, the Qinling-Dabie tract, which spans central China and areas to the west, encompassing Paleozoic through Triassic igneous rocks that formed in diverse settings; and (3) assemblages of late Paleozoic and Mesozoic rocks that define two other tracts in the Tethysides, the 100

  20. Remelting of Neoproterozoic relict volcanic arcs in the Middle Jurassic: Implication for the formation of the Dexing porphyry copper deposit, Southeastern China (United States)

    Liu, Xuan; Fan, Hong-Rui; Santosh, M.; Hu, Fang-Fang; Yang, Kui-Feng; Li, Qiu-Li; Yang, Yue-Heng; Liu, Yongsheng


    The Dexing copper deposit in southeastern China is a typical non-arc porphyry deposit, the origin of which has been a topic of debate for several decades. Here we present new results from U-Pb geochronology, whole-rock chemistry and Sr-Nd-Hf-O isotopic investigations on the ore-forming granodioritic porphyry. LA-ICPMS zircon U-Pb data suggest that the granodioritic porphyry was formed in the Middle Jurassic (ca. 172.5 Ma) probably associated with lithospheric thinning driven by either sub-continental lithospheric mantle delamination or asthenospheric upwelling. The porphyry displays both arc-like and adakitic trace element signatures. The adakitic features suggest that HREE (heavy rare earth elements)-rich minerals such as garnet and hornblende, in the absence of plagioclase resided in the source region. The arc-like signatures are broadly comparable with those of the proximal Neoproterozoic island arc rocks including the keratophyre from Shuangxiwu Group and associated granitoids indicating a potential genetic relationship. The porphyry has chondritic ɛNd(t) of - 0.28 to 0.25 and radiogenic ɛHf(t) of 2 to 7, and correspondingly, uniform two stage depleted mantle Nd model ages of 940-980 Ma and Hf model ages of 800-1100 Ma (mean ~ 920 Ma). On Nd and Hf isotopic evolution diagrams, these values are markedly similar to those of the adjacent Neoproterozoic arc rocks when calculated forward to the Mid-Jurassic. Zircons of the porphyry show mantle-like oxygen isotope characters with δ18O values clustering in the range of 4.7-5.9‰, similar to the values for the Neoproterozoic arc rocks mentioned above. The geochemical and isotopic features recorded in our study suggest mantle-derived magmas with no significant supracrustal input for the source of the porphyry. With regard to the source of the Cu ore, we consider a model involving the remelting of sulfide-bearing arc-related lower crustal source. Furthermore, the occurrence of a Neoproterozoic VMS (volcanic massive

  1. Formation of the adakite-like granitoid complex and porphyry copper-gold deposit in Shaxi from southern Tancheng-Lujiang fault belt: A clue to the West Pacific plate subduction

    Institute of Scientific and Technical Information of China (English)

    LAN Xianghua; YANG Xiaoyong; YU Liangfan; ZHANG Qianming


    On the basis of the geological and geochemical studies, including chemical analysis of bulk rocks, rare-earth and trace element studies, fluid inclusion, and S and O isotopic analyses, the authors described the geo-logical background of the deposit in detail and presented significant proofs for the conditions of formation of the Shaxi porphyry copper-gold deposit. Compared with other large and supper-large porphyry copper deposits in China and the adjacent Cu-Au mineralized areas, the ore-forming processes and conditions were analyzed; and the possibil-ity of forming large porphyry copper deposits in the Shaxi area was discussed. The present study indicated that the ore-forming fluid and material were mainly of magmatic origin, while meteoric water played a certain role in the ore-forming processes. Interactions between subducting and overriding plates provided a major driving force for the formation of igneous rocks and the deposition of metal elements in East China since Jurassic. Based on the geo-chemical data of the Shaxi intrusive, it is found that the copper (gold) mineralization is closely related to the genesis of adakite-like intrusive in the Shaxi area. This adakite-like intrusive was formed in the subduction environment as a result of the subduction of the West Pacific plate toward the East China continent, where there is a great potential-ity to form a large porphyry copper deposit.

  2. Production of sulfur gases and carbon dioxide by synthetic weathering of crushed drill cores from the Santa Cruz porphyry copper deposit near Casa Grande, Pinal County, Arizona (United States)

    Hinkle, M.E.; Ryder, J.L.; Sutley, S.J.; Botinelly, T.


    Samples of ground drill cores from the southern part of the Santa Cruz porphyry copper deposit, Casa Grande, Arizona, were oxidized in simulated weathering experiments. The samples were also separated into various mineral fractions and analyzed for contents of metals and sulfide minerals. The principal sulfide mineral present was pyrite. Gases produced in the weathering experiments were measured by gas chromatography. Carbon dioxide, oxygen, carbonyl sulfide, sulfur dioxide and carbon disulfide were found in the gases; no hydrogen sulfide, organic sulfides, or mercaptans were detected. Oxygen concentration was very important for production of the volatiles measured; in general, oxygen concentration was more important to gas production than were metallic element content, sulfide mineral content, or mineral fraction (oxide or sulfide) of the sample. The various volatile species also appeared to be interactive; some of the volatiles measured may have been formed through gas reactions. ?? 1990.

  3. Early Carboniferous adakitic rocks in the area of the Tuwu deposit, eastern Tianshan, NW China: Slab melting and implications for porphyry copper mineralization (United States)

    Wang, Yin-Hong; Xue, Chun-Ji; Liu, Jia-Jun; Wang, Jian-Ping; Yang, Jun-Tao; Zhang, Fang-Fang; Zhao, Ze-Nan; Zhao, Yun-Jiang; Liu, Bin


    Existing geochronological and geochemical data for the Early Carboniferous magmatic rocks in the eastern Tianshan, Xinjiang, have been interpreted in a variety of theories regarding petrogenesis and geodynamic setting. The proposed settings include rift, back-arc basin, passive continental margin, island arc, ridge subduction, and post-collisional environment. To evaluate these possibilities, we present new SHRIMP zircon U-Pb geochronology and geochemical data, whole-rock geochemical, Hf isotope, and S isotope data for tonalitic rocks and ores associated with the Tuwu porphyry copper deposit located in the center of the late Paleozoic Dananhu-Tousuquan arc, eastern Tianshan. SHRIMP zircon U-Pb dating indicates that the magmatic activity and thus associated copper mineralization occurred ca.332 Ma. The tonalitic rocks are calc-alkaline granites with A/CNK values ranging from 1.16 to 1.58; are enriched in K, Rb, Sr, and Ba; and are markedly depleted in Nb, Ta, Ti, and Th. They show geochemical affinities similar to adakites, with high Sr, Al2O3, and Na2O contents and La/Yb ratios; low Y and Yb contents; and slight positive Eu anomalies. In situ Hf isotopic analyses of zircons yielded positive initial εHf(t) values ranging from 6.9 to 17.2. The δ34S values of the ore sulfides range from -3.0‰ to +1.7‰, reflecting a deep sulfur source. Our results indicate that the paleo-Tianshan oceanic slab was being simultaneously subducted northward beneath the Dananhu-Tousuquan arc, and southward beneath the Aqishan-Yamansu arc during the Early Carboniferous. The Tuwu adakitic tonalitic rocks were derived from the partial melting of the subducted paleo-Tianshan oceanic slab, which was subsequently hybridized by mantle wedge peridotites. The slab-derived magmas have considerably high copper contents and are highly oxidized, thus leading to porphyry copper mineralization. Such Early Carboniferous tonalitic rocks that are widespread in the eastern Tianshan define a province

  4. The geology, structure and mineralisation of the Oyu Tolgoi porphyry copper-gold-molybdenum deposits, Mongolia:A review

    Institute of Scientific and Technical Information of China (English)

    T.M. Mike Porter


    The Oyu Tolgoi cluster of seven porphyry Cu-Au-Mo deposits in southern Mongolia, define a narrow, linear, 12 km long, almost continuously mineralised trend, which contains in excess of 42 Mt of Cu and 1850 t of Au, and is among the largest high grade porphyry Cu-Au deposits in the world. These deposits lie within the Gurvansayhan island-arc terrane, a fault bounded segment of the broader Silurian to Carboniferous Kazakh-Mongol arc, located towards the southern margin of the Central Asian Orogenic Belt, a collage of magmatic arcs that were periodically active from the late Neoproterozoic to Permo-Triassic, extending from the Urals Mountains to the Pacific Ocean. Mineralisation at Oyu Tolgoi is associated with multiple, overlapping, intrusions of late Devonian (w372 to 370 Ma) quartz-monzodiorite intruding Devonian (or older) juvenile, probably intra-oceanic arc-related, basaltic lavas and lesser volcaniclastic rocks, unconformably overlain by late Devonian (w370 Ma) basaltic to dacitic pyroclastic and volcano sedimentary rocks. These quartz-monzodiorite intrusions range from early-mineral porphyritic dykes, to larger, linear, syn-, late- and post-mineral dykes and stocks. Ore was deposited within syn-mineral quartz-monzodiorites, but is dominantly hosted by augite basalts and to a lesser degree by overlying dacitic pyroclastic rocks. Following ore deposition, an allochthonous plate of older Devonian (or pre-Devonian) rocks was overthrust and a post-ore biotite granodiorite intruded at w365 Ma. Mineralisation is characterised by varying, telescoped stages of intrusion and alteration. Early A-type quartz veined dykes were followed by Cu-Au mineralisation associated with potassic alteration, mainly K-feldspar in quartz-monzodiorite and biotite-magnetite in basaltic hosts. Downward reflux of cooled, late-magmatic hydrothermal fluid resulted in intense quartz-sericite retrograde alteration in the upper parts of the main syn-mineral intrusions, and an equivalent chlorite

  5. 新疆谢米斯台地区斑岩型铜矿化的发现及其意义%The Discovery of Porphyry Copper Mineralization in Xiemisitai Area of Xinjiang and Its Significance

    Institute of Scientific and Technical Information of China (English)

    王居里; 王建其; 胡洋; 涂一安; 王敏; 令伟伟


    继在新疆谢米斯台地区玄武岩中发现自然铜矿化后,在谢米斯台地区中-酸性次火山岩中发现具有一定规模的斑岩型铜矿化。原生硫化物主要为黄铜矿、黄铁矿和斑铜矿。斑岩型铜矿化主要发育于蚀变的英安斑岩、流纹斑岩和安山玢岩中,矿化岩石中发育强烈的绿帘石化、绿泥石化、碳酸盐化、硅化,局部发育泥化。区内斑岩型铜矿化的发现,表明新疆谢米斯台地区存在两种类型铜矿化,有望取得铜矿找矿新突破。矿化次火山岩及其下部的浅成侵入体可能是区内斑岩型铜矿床找矿评价的重要目标。%The porphyry copper mineralization with a certain scale was found in intermediate-acidic subvolcanic rocks after the discovery of native copper mineralization in basalts of Xiemisitai area, Xinjiang. The primary sulfides are mainly chalcopyrite, pyrite and bornite. The porphyry copper mineralization occurs mainly in the altered rhyolitic porphyry, dacitic porphyry and andesitic porphyrite, and intense epidotization, chloritization, carbonation and silicification and weak argillation occur in the mineralized rocks. This discovery shows that there are two types of copper mineralization in Xiemisitai area, and it is expected that new breakthrough can be made in further copper prospecting. The mineralized subvolcanic rocks and the hypabyssal intrusive bodies beneath the subvolcanic rocks may be the important targets for the further porphyry copper prospecting in Xiemisitai area.

  6. The geology, structure and mineralisation of the Oyu Tolgoi porphyry copper-gold-molybdenum deposits, Mongolia: A review

    Directory of Open Access Journals (Sweden)

    T.M. (Mike Porter


    Mineralisation is characterised by varying, telescoped stages of intrusion and alteration. Early A-type quartz veined dykes were followed by Cu-Au mineralisation associated with potassic alteration, mainly K-feldspar in quartz-monzodiorite and biotite-magnetite in basaltic hosts. Downward reflux of cooled, late-magmatic hydrothermal fluid resulted in intense quartz-sericite retrograde alteration in the upper parts of the main syn-mineral intrusions, and an equivalent chlorite-muscovite/illite-hematite assemblage in basaltic host rocks. Uplift, facilitated by syn-mineral longitudinal faulting, brought sections of the porphyry deposit to shallower depths, to be overprinted and upgraded by late stage, shallower, advanced argillic alteration and high sulphidation mineralisation. Key controls on the location, size and grade of the deposit cluster include (i a long-lived, narrow faulted corridor; (ii multiple pulses of overlapping intrusion within the same structure; and (iii enclosing reactive, mafic dominated wall rocks, focussing ore.

  7. Zircon U-Pb and molybdenite Re-Os geochronology and Sr-Nd-Pb-Hf isotopic constraints on the genesis of the Xuejiping porphyry copper deposit in Zhongdian, Northwest Yunnan, China (United States)

    Leng, Cheng-Biao; Zhang, Xing-Chun; Hu, Rui-Zhong; Wang, Shou-Xu; Zhong, Hong; Wang, Wai-Quan; Bi, Xian-Wu


    The Xuejiping porphyry copper deposit is located in northwestern Yunnan Province, China. Tectonically, it lies in the southern part of the Triassic Yidun island arc. The copper mineralization is mainly hosted in quartz-dioritic and quartz-monzonitic porphyries which intruded into clastic-volcanic rocks of the Late Triassic Tumugou Formation. There are several alteration zones including potassic, strong silicific and phyllic, argillic, and propylitic alteration zones from inner to outer of the mineralized porphyry bodies. The ages of ore-bearing quartz-monzonitic porphyry and its host andesite are obtained by using the zircon SIMS U-Pb dating method, with results of 218.3 ± 1.6 Ma (MSWD = 0.31, N = 15) and 218.5 ± 1.6 Ma (MSWD = 0.91, N = 16), respectively. Meanwhile, the molybdenite Re-Os dating yields a Re-Os isochronal age of 221.4 ± 2.3 Ma (MSWD = 0.54, N = 5) and a weighted mean age of 219.9 ± 0.7 Ma (MSWD = 0.88). They are quite in accordance with the zircon U-Pb ages within errors. Furthermore, all of them are contemporary with the timing of the Garzê-Litang oceanic crust subduction in the Yidun arc. Therefore, the Xuejiping deposit could be formed in a continental margin setting. There are negative ɛNd(t) values ranging from -3.8 to -2.1 and relatively high initial 87Sr/86Sr ratios from 0.7051 to 0.7059 for the Xuejiping porphyries and host andesites. The (206Pb/204Pb)t, (207Pb/204Pb)t and (208Pb/204Pb)t values of the Xuejiping porphyries and host andesites vary from 17.899 to 18.654, from 15.529 to 15.626, and from 37.864 to 38.52, respectively, indicative of high radiogenic Pb isotopic features. In situ Hf isotopic analyses on zircons by using LA-MC-ICP-MS exhibit that there are quite uniform and slightly positive ɛHf(t) values ranging from -0.2 to +3.2 (mostly between 0 and +2), corresponding to relatively young single-stage Hf model ages from 735 Ma to 871 Ma. These isotopic features suggest that the primary magmas of the Xuejiping porphyries and

  8. Ultra-deep oxidation and exotic copper formation at the late pliocene boyongan and bayugo porphyry copper-gold deposits, surigao, philippines: Geology, mineralogy, paleoaltimetry, and their implications for Geologic, physiographic, and tectonic controls (United States)

    Braxton, D.P.; Cooke, D.R.; Ignacio, A.M.; Rye, R.O.; Waters, P.J.


    The Boyongan and Bayugo porphyry copper-gold deposits are part of an emerging belt of intrusion-centered gold-rich deposits in the Surigao district of northeast Mindanao, Philippines. Exhumation and weathering of these Late Pliocene-age deposits has led to the development of the world's deepest known porphyry oxidation profile at Boyongan (600 m), and yet only a modest (30-70 m) oxidation profile at adjacent Bayugo. Debris flows, volcanic rocks, and fluviolacustrine sediments accumulating in the actively extending Mainit graben subsequently covered the deposits and preserved the supergene profiles. At Boyongan and Bayugo, there is a vertical transition from shallower supergene copper oxide minerals (malachite + azurite + cuprite) to deeper sulfide-stable assemblages (chalcocite ?? hypogene sulfides). This transition provides a time-integrated proxy for the position of the water table at the base of the saturated zone during supergene oxidation. Contours of the elevation of the paleopotentiometric surface based on this min- eralogical transition show that the thickest portions of the unsaturated zone coincided with a silt-sand matrix diatreme breccia complex at Boyongan. Within the breccia complex, the thickness of the unsaturated zone approached 600 in, whereas outside the breccia complex (e.g., at Bayugo), the thickness averaged 50 m. Contours of the paleopotentiometric surface suggest that during weathering, groundwater flowed into the breccia complex from the north, south, and east, and exited along a high permeability zone to the west. The high relief (>550 m) on the elevation of the paleopotentiometric surface is consistent with an environment of high topographic relief, and the outflow zone to the west of the breccia complex probably reflects proximity to a steep scarp intersecting the western breccia complex margin. Stable isotope paleoaltimetry has enabled estimation of the elevation of the land surface, which further constrains the physiographic setting

  9. Application of fuzzy logic and fuzzy AHP to mineral prospectivity mapping of porphyry and hydrothermal vein copper deposits in the Dananhu-Tousuquan island arc, Xinjiang, NW China (United States)

    Zhang, Nannan; Zhou, Kefa; Du, Xishihui


    Mineral prospectivity mapping (MPM) is a multi-step process that ranks promising target areas for further exploration. Fuzzy logic and fuzzy analytical hierarchy process (AHP) are knowledge-driven MPM approaches. In this study, both approaches were used for data processing, based on which MPM was performed for porphyry and hydrothermal vein copper deposits in the Dananhu-Tousuquan island arc, Xinjiang. The results of the two methods were then compared. The two methods combined expert experience and the Studentized contrast (S(C)) values of the weights-of-evidence approach to calculate the weights of 15 layers, and these layers were then integrated by the gamma operator (γ). Through prediction-area (P-A) plot analysis, the optimal γ for fuzzy logic and fuzzy AHP was determined as 0.95 and 0.93, respectively. The thresholds corresponding to different levels of metallogenic probability were defined via concentration-area (C-A) fractal analysis. The prediction performances of the two methods were compared on this basis. The results showed that in MPM based on fuzzy logic, the area under the receiver operating characteristic (ROC) curve was 0.806 and 81.48% of the known deposits were predicted, whereas in MPM based on fuzzy AHP, the area under the ROC curve was 0.862 and 92.59% of the known deposits were predicted. Therefore, prediction based on fuzzy AHP is more accurate and can provide directions for future prospecting.

  10. Systematic sulfur stable isotope and fluid inclusion studies on veinlet groups in the Sarcheshmeh porphyry copper deposit: based on new data

    Directory of Open Access Journals (Sweden)

    Mohammad Maanijou


    Full Text Available Mineralization occurred by intrusion of granodioritic stock of middle Miocene in volcano–sedimenrary rocks in Sarcheshmeh of early Tertiary age. This research is based on samples of new drilled boreholes and benches of 2500m elevation. Based on mineralogy and crosscutting relationships, at least four groups of veinlets pertaining to four stages of mineralization were recognized. Sulfur isotope studies in the Sarcheshmeh porphyry copper deposit were conducted on pyrite, chalcopyrite, molybdenite and anhydrites of four groups of veinlets. The δ34S values in the sulfides and sulfates range from -2.2 to 1.27‰ and from 10.2 to 14.5 ‰, respectively. The average δ34S value in the sulfides is 1‰ and that for the sulfates is about 13‰. Considering these results, it can be concluded that the sulfides made up of a fluid that its sulfur has a magmatic origin. Also, fluid inclusions of different veinlet groups were studied, showing high temperature, high salinity and the occurrence of boiling in the mineralizing fluids. Moreover, these studies indicate presence of three types of fluids including magmatic, meteoritic and mixture of these two fluids in alteration and mineralizion processes.

  11. Caldera complex, hosted rocks and alteration of the Yandong porphyry copper deposit in Eastern Tianshan, Xinjiang%新疆延东斑岩铜矿床火山机构、容矿岩石及热液蚀变

    Institute of Scientific and Technical Information of China (English)

    申萍; 潘鸿迪; 董连慧; 杨俊弢; 沈远超; 代华五; 关维娜; 赵云江


    延东斑岩铜矿床位于新疆东天山晚古生代大南湖岛弧中.延东矿区出露地层是石炭纪企鹅山组火山-沉积岩,我们研究提出延东矿区出露的火山-沉积岩以及浅成侵入岩为石炭纪火山喷发-岩浆侵入产物,并将其划分成两个旋回五个岩相:第一旋回包括溢流相(玄武岩和安山岩)、爆发相(集块角砾熔岩)和爆发-沉积相(凝灰岩);第二旋回包括次火山相(闪长玢岩和闪长岩)和浅成侵入相(斜长花岗斑岩).容矿岩石是次火山相的闪长玢岩和闪长岩以及浅成侵入相的斜长花岗斑岩.闪长玢岩发育中性斑岩蚀变系统,包括内部的绢云母-绿泥石蚀变带和绿泥石-绢云母蚀变带和外围的青磐岩化带,其中绢云母-绿泥石蚀变带控制本区部分富矿体的形成和分布;斜长花岗斑岩发育酸性斑岩蚀变系统,从中心向外依次为黄铁绢英岩化带、强绢云母化带和弱绢云母化带,黄铁绢英岩化带控制本区部分富矿体的形成和分布.这两个蚀变系统以钾硅酸盐化蚀变不发育和绢云母化广泛发育为特点.%Yandong large-size porphyry copper deposit is located in the Late Paleozoic Dananhu island arc in Eastern Tianshan, Xinjiang. Lower Carboniferous Qi'eshan Group occurred in the Yandong region. New results recognize a volcanic apparatus at Yandong that includes two cycles comprising five lithofacies. The first cycle consists of the effusive ( basalt and andesite), explosive (auto-brecciated lava) and pyroclasrie phases (tuff). The second cycle is characterized by the intermediate and felsic intrusions. The intrusions, including the diorite porphyry, aplite diorite and plagiogranite porphyry, are ore-bearing intrusions. Both diorite porphyry (including aplite diorite)and plagiogranite porphyry host the bulk of the copper mineralization at Yandong and have been overprinted by the two distinct alteration systems. Diorite porphyry has been overprinted by three

  12. Multimillion year thermal history of a porphyry copper deposit: application of U-Pb, 40Ar/39Ar and (U-Th)/He chronometers, Bajo de la Alumbrera copper-gold deposit, Argentina (United States)

    Harris, Anthony C.; Dunlap, W. James; Reiners, Peter W.; Allen, Charlotte M.; Cooke, David R.; White, Noel C.; Campbell, Ian H.; Golding, Suzanne D.


    Application of multiple chronometers (including U-Pb and 40Ar/39Ar geochronology and zircon and apatite (U-Th)/He thermochronology) to porphyry intrusions at the Bajo de la Alumbrera porphyry copper-gold deposit, Argentina, reveals a complex history of reheating that spans millions of years. Previous U-Pb geochronology, combined with our new 40Ar/39Ar data, shows that the multiple porphyritic intrusions at Bajo de la Alumbrera were emplaced during two episodes, the first at about 8.0 Ma (P2 and associated porphyries) and the second about a million years later (Early and Late P3 porphyries). Complex overprinting alteration events have obscured the earliest hydrothermal history of the deposit. By contrast, 40Ar/39Ar data reveal the close temporal relationship of ore-bearing potassic alteration assemblages (7.12 ± 0.13 Ma; biotite) to the emplacement of the P3 intrusions. Consistent with low closure temperatures, younger ages have been determined for associated hydrothermal alkali feldspar (6.82 ± 0.05 Ma and 6.64 ± 0.09 Ma). The temperature-sensitive Ar data also record an unexpected prolonged cooling history (to below 200°C) extending to 5.9 Ma. Our data suggest that the Bajo de la Alumbrera system underwent protracted cooling, after the collapse of the main hydrothermal system, or that one or more low-temperature (~100-200°C) reheating events occurred after emplacement of the porphyritic intrusions at Bajo de la Alumbrera. These have been constrained in part by our new 40Ar/39Ar data (including multidomain diffusion modeling) and (U-Th)/He ages. Single-grain (U-Th)/He ages ( n = 5) for phenocrystic zircon from P2 and P3 intrusive phases bracket these thermal events to between 6.9 (youngest crystallization of intrusion) and 5.1 Ma. Multidomain modeling of alkali feldspar data (from both igneous and hydrothermal crystals) is consistent with the deposit cooling rapidly from magmatic temperatures to below about 300°C, with a more protracted history down to 150

  13. Metallogenetic epoch of the Almalyk porphyry copper ore field, Uzbekistan.and its geological significance%乌兹别克斯坦Almalyk斑岩铜矿田成矿时代及其地质意义

    Institute of Scientific and Technical Information of China (English)

    薛春纪; 段士刚; 柴凤梅; 木合塔尔·买买提; A.X.TypeceóekoB; 屈文俊


    The exploration of porphyry copper deposits in western Tianshan. Xinjiang, had attracted much attentions. The Almalyk copper deposit in western Tianshan. Uzbekistan, is one of the largest porphyry copper deposits in Asia, but has not well been dated. The Almalyk copper ore field is located in the southern part of Caledonian-Hercynian central I lanshan fold belt, and includes four copper deposits: Kalmakyr. Dalneye. Sarcheku and Kyzata. Copper mineralization occurred within the porphyries. The primary ores are characterized mainly by stockwork and disseminated structures, and the major metallic minerals are in assemblage of py-rite. chalcopyrite. molybdenite, hematite, magnetite, nature gold and bornite. The present paper obtains the weighted model age of 320. 1 ± 2. 3 Ma and an isochron age of 317.6±2. 5 Ma based on the Re-Os isotopic method by using the molybdenites from the Sarcheku copper-molybdenum ores. On the basis of the sequence of magmatic formation in this area, it is suggested that the tectonomagmatic hydrothermal process in Almalyk ore field started at the early Carboniferous, developed during the late Carboniferous, and finished at the early Permian, and the porphyry copper mineralization mainly occurred during the late Carboniferous. The world-class large and supper large porphyry copper mineralization including the Almalyk copper deposit in western Tianshan is closely related to the complex arc magmatic geological processes resulted from the sulxluction of paleo-Asia ocean crust under Kazakhstan-Yili plate, which happened mainly from the middle Devonian to the late Carboniferous (D2 - C2).%新疆西天山斑岩铜矿找矿勘查备受关注.乌兹别克斯坦Almalyk斑岩铜矿田处在西天山西段,铜矿规模属亚洲第二大,但其成矿时代还没有准确厘定.在区域地质构造中,Almalvk铜矿田位于中天山加里东 华力西褶皱带南部边缘,包括Kalmakyr、Dalneye、Sarcheku和Kyzata等4个铜矿床,铜成矿主要发生

  14. Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit. (United States)

    Diaby, N; Dold, B; Rohrbach, E; Holliger, C; Rossi, P


    Mine tailings are a serious threat to the environment and public health. Remediation of these residues can be carried out effectively by the activation of specific microbial processes. This article presents detailed information about temporal changes in bacterial community composition during the remediation of a section of porphyry copper tailings deposited on the Bahía de Ite shoreline (Peru). An experimental remediation cell was flooded and transformed into a wetland in order to prevent oxidation processes, immobilizing metals. Initially, the top oxidation zone of the tailings deposit displayed a low pH (3.1) and high concentrations of metals, sulfate, and chloride, in a sandy grain size geological matrix. This habitat was dominated by sulfur- and iron-oxidizing bacteria, such as Leptospirillum spp., Acidithiobacillus spp., and Sulfobacillus spp., in a microbial community which structure resembled acid mine drainage environments. After wetland implementation, the cell was water-saturated, the acidity was consumed and metals dropped to a fraction of their initial respective concentrations. Bacterial communities analyzed by massive sequencing showed time-dependent changes both in composition and cell numbers. The final remediation stage was characterized by the highest bacterial diversity and evenness. Aside from classical sulfate reducers from the phyla δ-Proteobacteria and Firmicutes, community structure comprised taxa derived from very diverse habitats. The community was also characterized by an elevated proportion of rare phyla and unaffiliated sequences. Numerical ecology analysis confirmed that the temporal population evolution was driven by pH, redox, and K. Results of this study demonstrated the usefulness of a detailed follow-up of the remediation process, not only for the elucidation of the communities gradually switching from autotrophic, oxidizing to heterotrophic and reducing living conditions, but also for the long term management of the remediation


    Institute of Scientific and Technical Information of China (English)



    The Narigongma porphyry molybdenum (-copper) deposit in Southern Qinghai Province is located in the northern part of Yulong metallogenic belt. Research on the deposit recognizes three types of alteration in the orefield, i.e. K-silicate alteration (biotite-K feldspar), propylitic alteration (chlorite-epidote ± calcite) and feldspar-destructive alteration (sericite ± kaolin ± calcite ± anhydrite). The metallogenesis is closely related to the quartz-molybdenite ± anhydrite ± chalcopyrite ± pyrite vein and molybdenite ± pyrite ± chalcopyrite vein.%通过对纳日贡玛斑岩钼(铜)矿床的蚀变类型的详细研究,识别了矿床蚀变的3种主要类型:钾硅酸盐化、青磐岩化和长石分解蚀变.前二者为矿区早期形成的蚀变,长石分解蚀变形成于晚期.钾硅酸盐化蚀变主要以黑云母化、钾长石化为特征,青磐岩化以脉状绿泥石、绿帘石、方解石等蚀变矿物的发育为基本特征,长石分解蚀变则发育绢云母、高岭土、方解石、硬石膏等矿物.研究认为矿化与石英-辉钼矿±硬石膏±黄铜矿±黄铁矿脉、辉钼矿±黄铁矿±黄铜矿脉有较为密切的联系.

  16. 甘肃龙尾沟斑岩型铜(钨)矿床成矿特征及形成环境%Geological Characteristics and Metallogenic Environment of the Longweigou Porphyry Copper(tungsten) Deposit,Gansu

    Institute of Scientific and Technical Information of China (English)

    贾群子; 马云海; 全守村; 王建军; 肖朝阳; 李金超


    龙尾沟铜(钨)矿床是祁连山地区新近发现的一处斑岩型矿床,其评价及研究对祁连山地区铜矿勘查具有重要的指导和借鉴作用.本文通过对含矿斑岩年代学及地球化学、矿体产出特征及矿石物质组成、围岩蚀变等进行了系统研究,结果表明,花岗闪长斑岩形成年龄为358.7 Ma;矿体呈似层状、透镜状和脉状产出,主要产于高钾碱性系列斑岩体内,并受近南北向构造控制;矿石矿物主要为黄铜矿、黄铁矿、磁黄铁矿、白钨矿,呈细脉一浸染状、浸染状产出;矿化以富铜、钨、金贫钼为特征;与成矿关系密切的围岩蚀变主要为绢英岩化,次为钾硅酸盐化和硅化;矿床成矿时代为海西早期,形成于陆内造山伸展环境.从成矿背景分析认为祁连山地区陆内造山环境所形成的斑岩型铜矿具有良好的找矿前景.%The Longweigou porphyry copper( tungsten) deposit, a newly found deposit, lies in the Oulongbuluke uplift belt of the Qilian orogenic belt. The evaluation and research of the Longweigou copperCtungsten) ore deposit will present important guidance and reference for copper exploration in the Qilian Mountain area. The chronology and the geochemistry of the ore-bearing porphyry deposit were studied and the occurrence features of the deposit, the components of gold mineral and the alteration of the wall rock were investigated. Results showed that the formation age of the granodiorite porphyry is 358. 7Ma; and that the ore-body, which has occurrences of stratiform or lenticular or vein, occurs mainly in the high potassium alkali series porphyry and is controlled by NS structures; and that chalcopyrite, pyrite, pyrrhotite, and scheelite are main ore minerals, which have veinlet-disseminated and disseminated structures; and that mineralization is characterized by enriching copper, tungsten and gold and depleting molybdenum; and that the mineralization related wall-rock alterations are

  17. Examination of chloritization of biotite as a tool for reconstructing the physicochemical parameters of mineralization and associated alteration in the Zafarghand porphyry copper system, Ardestan, Central Iran: mineral-chemistry and stable isotope analyses (United States)

    Aminroayaei Yamini, Maryam; Tutti, Faramarz; Aminoroayaei Yamini, Mohammad Reza; Ahmadian, Jamshid; Wan, Bo


    The chloritization of biotite and stable isotopes of silicate have been studied for the Zafarghand porphyry copper deposit, Ardestan, Iran. The studied area, in the central part of the Urumieh-Dokhtar magmatic belt, contains porphyry-style Cu mineralization and associated hydrothermal alteration within the Miocene (19-26 Ma, Zircon U-Pb age) granodioritc stock and adjacent andesitic to rhyodacitic volcanic rocks (ca. 56 Ma, zircon U-Pb age). The primary and secondary biotite that formed during potassic alteration in this porphyry and these volcanic host rocks are variably chloritized. Chloritization of biotite pseudomorphically is characterized by an increase in MgO, FeOt, and MnO, with decreasing in SiO2, K2O, and TiO2. Based on the Ti-in-biotite geothermometer of Henry et al. (Am Mineral 90:316-328, 2005) and Al-in-chlorite geothermometer of Cathelineau (Clay Miner 23:417-485, 1988), crystallization temperatures of primary biotite representative of magmatic conditions and later chloritization temperature range from 617° to 675 °C ± 24 °C and 177° to 346 °C, respectively. Calculated isotopic compositions of fluids that chloritized primary and secondary biotite display isotopic compositions of 1.1 to 1.7 per mil for δ18O and -19.9 to -20.5 per mil for δD consistent with meteoric water. Sericite, barren, and A-type-quartz veins from phyllic alteration were produced by mixed magmatic and meteoric water with δ18O values from -2.8 to 2.5 and δD values of ˜ -23 per mil; the narrow range of δD values of the propylitic epidote may be due to a meteoric water with δ18O values from 0.8 to 1.6 and δD values from -14.6 to -16.9 per mil.

  18. Arc-related porphyry molybdenum deposit model: Chapter D in Mineral deposit models for resource assessment (United States)

    Taylor, Ryan D.; Hammarstrom, Jane M.; Piatak, Nadine M.; Seal, Robert R., II


    This report provides a descriptive model for arc-related porphyry molybdenum deposits. Presented within are geological, geochemical, and mineralogical characteristics that differentiate this deposit type from porphyry copper and alkali-feldspar rhyolite-granite porphyry molybdenum deposits. The U.S. Geological Survey's effort to update existing mineral deposit models spurred this research, which is intended to supplement previously published models for this deposit type that help guide mineral-resource and mineral-environmental assessments.

  19. The Re-Os isotope system of the Xiongcun porphyry copper-gold deposit, Tibet%西藏雄村斑岩铜矿床辉钼矿Re-Os同位素体系

    Institute of Scientific and Technical Information of China (English)

    黄勇; 唐菊兴; 丁俊; 张丽; 郎兴海


    辉钼矿Re-Os同位素测年是现今研究斑岩铜矿成矿时限最有效的手段.本文通过开展冈底斯成矿带雄村斑岩铜金矿辉钼矿Re-Os同位素年代学研究,并结合前人已发表的数据,认为雄村斑岩铜金矿床成矿时限为171~175Ma.Ⅰ号矿体可能受到始新世大规模的岩浆活动扰动,辉钼矿在经历过后期热事件影响,在辉钼矿中形成有极微量富Re的K-硅酸盐矿物,Ⅰ号矿体辉钼矿Re含量比Ⅱ号矿体以及Ⅲ号矿体中辉钼矿Re含量高出1~4倍,其Re-Os同位素年龄比真实年龄偏低,不能完全代表成矿年龄.同时通过与冈底斯成矿带斑岩-矽卡岩铜钼矿床,钼/钼铜矿床的对比研究后发现,雄村斑岩铜金矿中辉钼矿Re含量比同一成矿带上中新世斑岩铜钼矿床中辉钼矿Re含量高出一个数量级,比古新世—始新世斑岩钼矿/钼铜矿床中辉钼矿Re含量高出两个数量级.辉钼矿Re含量变化特征与成矿物质的来源、钼的浓度、成矿母岩组分以及成矿期间的物理/化学条件有关.%Re-Os dating of molybdenite is an efficient means to restrict the time of mineralization. The age of mineralization of the Xiongcun porphyry copper-gold deposit is confined between 171 Ma and 175 Ma based on this study and other data available. No. Ⅰ ore body of the Xiongcun deposit was affected by later magmtic thermal event. Molybdenite contains trace K-Si silicate enriched in Re. As a result of this event, the Re content of molybdenite is one to four times higher than that of molybdenite in No.Ⅱ ore body and No. Ⅲ ore body, and the age of molybdenite in No. Ⅰ ore body is younger than the real age. The authors also compared the Re content of molybdenite between this deposit and other porphyry-skarn deposits within this belt and found that the content of Re shows systematic variation. The Re content of the Xiongcun porphyry copper-gold deposit is one order of magnitude high than that of Miocene

  20. Study on Mixed Spectra of Alteration Zones in Porphyry Copper Deposits Based on the Hapke and Shkuratov Models%基于Hapke和Shkuratov模型的斑岩铜矿蚀变带混合波谱研究

    Institute of Scientific and Technical Information of China (English)

    代晶晶; 李庆亭


    Abstract:Spectral mixture models for minerals play an important role in extraction of alteration information.The Hapke and Shkuratov models are two important non-linear spectral mixture models.This paper analyzes the characteristics of these two models,and puts forward a new method for simulating mixed spectral of mineral assemblages and rocks based on them.And we simulate the spectra of typical mineral assemblages of the alteration zones (potassic,phyllic,argillic and propylitic zones),taking the alteration zones in porphyry copper deposits as examples.The results can provide a theoretical basis for studies of alteration zones in porphyry copper deposits.%矿物光谱混合模型研究对于蚀变带蚀变矿物的信息提取具有重要意义.本文基于目前两种主流的非线性光谱混合模型Hapke和Shkuratov模型,通过对两者特性的对比分析,提出了一种综合利用这两种模型进行矿物或岩石光谱混合模拟的思路,并针对斑岩型铜矿典型蚀变分带现象,进行钾化带、绢英岩化带、泥化带、青磐岩化带等典型蚀变带矿物组合光谱的模拟实验.本研究提取结果可以为斑岩铜矿蚀变带研究提供理论依据.

  1. 云南中旬岛弧带典型斑岩铜矿床围岩蚀变特征对比及其找矿意义%The comparison of the features of wall rock alteration and its prospecting significance in typical porphyry copper deposit in Zhongdian arc orogen, Yunnan

    Institute of Scientific and Technical Information of China (English)

    姜永果; 吴静; 李峰; 崔银亮; 张亚辉


    中甸岛弧带是斑岩型铜矿的矿集区,区内的斑岩铜矿床围岩蚀变强烈,蚀变分带明显,围岩蚀变与矿化关系密切.文章对分别位于中甸岛弧东、西部成矿带的春都和普朗斑岩铜矿床围岩蚀变及矿化特征进行了对比分析.研究结果表明,2个斑岩铜矿床的围岩蚀变类型主要表现形式以及蚀变分带模式基本相同,研究还得出中旬岛弧带斑岩铜矿床钾硅化带以及绢英岩化带的蚀变强度及其规模共同决定斑岩铜矿床的规模.中旬岛弧带斑岩铜矿床中,青磐岩化玢岩为找矿的间接标志,绢英岩化或钾硅化斑岩(玢岩)为找矿的直接标志.%Zhongdian arc orogen is an important centralized zone of porphyry copper, where the wall rock alteration strongly related with mineralization is fierce and alteration zones are obivious. The characteristics of the wall rock alteration and mineralization of Pulang in the eastern matollgenic belts and Chundu porphyry copper deposit in the western matollgenic belts of Zhongdian arc were compared and analysised in this article. The studies show that the wall rock alteration types and zonality of alteration are roughly the same between Pulang and Chunduin porphyry copper deposits, and that the scale of porphyry copper deposit are controlled by thestrength and scale of kali silicification zone and sericitolite zone as well. In the porphyry copper deposit of Zhongdian arc orgen belts, the propyliti-zation porphyrite is an indirect prospecting sign, while sericitolite porphyry and kali silicification are the direct prospecting signs.

  2. 云南香格里拉春都斑岩铜矿区围岩蚀变及矿化特征%Features of alteration and mineralization in the Chundu porphyry copper deposit, Xianggelila, Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    姜永果; 吴静; 李峰; 杨帆; 邹国富; 李建飞; 赵向东; 郭嵋


    春都斑岩铜矿床地处著名的印支期中甸-义敦岛弧成矿带南端。矿区出露闪长玢岩-花岗闪长斑岩复式岩体,成矿岩体为印支晚期的花岗闪长斑岩。围绕成矿岩体,围岩蚀变强烈,蚀变分带明显,由中心向外,依次出现硅化钾化带→绢英岩化带→硅化带→硅化黑云母化带→青磐岩化带→绢云母化及泥化带。区内蚀变与矿化关系密切,蚀变类型决定矿化程度,蚀变带的分布控制矿体产状。因此,围岩蚀变特征的研究将为矿区进一步找矿提供重要依据。%The Chundu porphyry copper deposit lies in the southernmost famous Zhongdian-Yidun island arc of the Indosinian Orogeny. There are cropping-out of multi-legs rock mass composed of diorite porphyrite and granodiorite-porphyly in the orefield. The granodiorite-porphyry is granodiorite -porphyry metallogenic rock mass in the orefield. There are fierce alteration of wall rock and visible zonality of alteration in the orefield sun'ounding the metallogenic rock mass. There exist kali silicification zone→sericitolite zone~silicification and biotitization zone→silification zone→propylitization zone→ sericitization and argillization zone ,from centre to outside surrounding the metallogenic rock mass. The alteration is closely related with mineralization in this area. The degree of mineralization depends on the types of alteration and the occurrence of orebody is controlled by the distribution of alteration zones. So the study of alteration of wall rock will provide important evidence for further prospecting in the orefield.

  3. 西藏雄村斑岩型铜金矿红柱石成因矿物学特征%Genetic Mineralogy of Andalusite in Xiongcun Porphyry Copper-Gold Oredeposit, Tibet

    Institute of Scientific and Technical Information of China (English)

    黄勇; 丁俊; 唐菊兴; 张丽; 郎兴海


    雄村斑岩铜金矿中广泛分布有红柱石,红柱石主要呈三种产出状态:①石英-钾长石-白云母/绢云母-红柱石组合;②红柱石-石英-绢云母/白云母组合;③石英-红柱石-硫化物脉.矿物组合关系、红柱石结构和成分等特征均表明红柱石属热液成因.早期钾硅酸盐化带中的石英-钾长石-白云母/绢云母-红柱石组合形成于高温(大于550℃)、低+K/+H比值环境.随着热液体系温压降低,热液体系+K/+H比值升高,早期钾硅酸盐化被黄铁绢英岩化强烈交代,形成相对较低温环境的红柱石-石英-绢云母/白云母组合,黄铁绢英岩化交代早期钾硅酸盐化过程可能伴随有大量循环大气降水进入崩塌的热液体系.石英-红柱石-硫化物脉分布较少,且只分布在黄铁绢英岩化外围,硫化物以黄铁矿为主,脉体两侧见有较为宽广的绢云母蚀变晕,形成于相对低温环境的高+K/+H比值环境.雄村斑岩铜金矿中的热液成因红柱石特征与智利的El Salvador斑岩矿床中热液红柱石特征类似,富含Al2O3的火山岩/侵入岩为红柱石提供了良好的物质条件,同时广泛分布的热液红柱石重塑了岩浆-热液过程中的P-T条件.%There are abundant andalusites in the Xiongcun porphyry copper-gold deposit. Three major assemblages are recognized, i.e., quartz-K-feldspar-muscovite/sericite-andalusite assemblage, andalusite-quartz-sericite/ muscovite assemblage, and quartz - andalusite - sulfide veins. The mineral association, texture and composition of andalusites indicate that the andalusites are of hydrothermal type. The quartz-K-feldspar-muscovite/ sericite-andalusite assemblage in early K-silicate alteration zone was formed under the conditions of fairly high temperatures (above 550℃) and relatively low +K/+H ratios. Early K-silicate alteration was replaced by later phyllic/sericitic alteration under lower P-T and higher +K/+H conditions, and meteoric water probably

  4. Temporal and spatial distribution of alteration, mineralization and fluid inclusions in the transitional high-sulfidation epithermal-porphyry copper system at Red Mountain, Arizona (United States)

    Lecumberri-Sanchez, Pilar; Newton, M. Claiborne; Westman, Erik C.; Kamilli, Robert J.; Canby, Vertrees M.; Bodnar, Robert J.


    Red Mountain, Arizona, is a Laramide porphyry Cu system (PCD) that has experienced only a modest level of erosion compared to most other similar deposits in the southwestern United States. As a result, the upper portion of the magmatic–hydrothermal system, which represents the transition from shallower high-sulfidation epithermal mineralization to deeper porphyry Cu mineralization, is well preserved. Within the Red Mountain system, alteration, mineralization and fluid inclusion assemblages show a systematic distribution in both time and space. Early-potassic alteration (characterized by the minerals biotite and magnetite) is paragenetically earlier than late-potassic alteration (K-feldspar–anhydrite) and both are followed by later phyllic (sericite–pyrite) alteration. Advanced argillic alteration (pyrophyllite–alunite–other clay minerals) is thought to be coeval with or postdate phyllic alteration. Minerals characteristic of advanced argillic alteration are present in the near surface. Phyllic alteration extends to greater depths compared to advanced argillic alteration. Early-potassic and late-potassic alteration are only observed in the deepest part of the system. Considerable overlap of phyllic alteration with both early-potassic and late-potassic alteration zones is observed. The hypogene mineralization contains 0.4–1.2% Cu and is spatially and temporally related to the late-potassic alteration event. Molybdenum concentration is typically In the deepest part of the system, an early generation of low-to-moderate density and salinity liquid + vapor inclusions with opaque daughter minerals is followed in time by halite-bearing inclusions that also contain opaque daughter minerals indicating that an early intermediate-density magmatic fluid evolved to a high-density, high-salinity mineralizing fluid. The increase in density and salinity of fluids with time observed in the deeper parts of the system may be the result of immiscibility (“boiling”) of


    Institute of Scientific and Technical Information of China (English)

    于宏东; 金建文


    This paper performs a research on process mineralogy of a porphyry copper-molybdenum ore containing arsenic in Peru, by which the mode of occurrence of arsenic, copper, molybdenum in the ore is investigated, thus the mineralogy material for the ore of this type is enriched and an analysis on the mineralogy factors which influence the mineral processing targets is carried on. The results of process mineralogy show that the oxidation rate is quite low in the ore of this type, and the copper and molybdenum are easy to acquire a high recovery during mineral processing circuit, thus it is easy to achieve more ideal mineral processing targets. However, the arsenic in the ore is also of remarkable concentration in the copper-concentrated ore, more attention should be paid on the trend of tennantite in mineral separation process and produce copper concentrate with high and low arsenic by take full advantage of the small difference in the floatable property between the tennantite and chalcopyrite.%对秘鲁某斑岩型含砷铜钼矿进行了工艺矿物学研究,查明了矿石中砷、铜、钼等元素的赋存状态,丰富了该类型矿石的矿物学资料,并就影响选矿指标的矿物学因素进行了分析.工艺矿物学研究结果表明,该类型矿石的氧化率比较低,铜钼应具有较高的选矿回收率,选别作业时容易获得较理想的选矿指标,但矿石中的砷会在铜精矿中有显著的富集,应该重视砷黝铜矿在选矿流程中的走向,充分利用砷黝铜矿与黄铜矿之间浮游性的微小差异生产高、低砷铜精矿.

  6. Paired Magmatic-Metallogenic Belts in Myanmar - an Andean Analogue? (United States)

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


    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.

  7. 安徽庐枞沙溪斑岩铜矿蚀变及矿化特征研究%Characteristics of alteration and mineralization of the Shaxi porphyry copper deposit, Luzong area, Anhui Province

    Institute of Scientific and Technical Information of China (English)

    袁峰; 周涛发; 王世伟; 范裕; 汤诚; 张千明; 俞沧海; 石诚


    沙溪斑岩铜矿是长江中下游成矿带中部庐枞火山岩盆地外围的一个大型铜矿床.本文在前人工作基础上,基于详细的野外观察和系统的岩相学、矿相学工作,详细研究了矿床的蚀变特征及分带.结果表明,矿床的蚀变类型有钾硅酸盐化、青磐岩化、长石分解蚀变和高岭土化,从深到浅依次发育有钾硅酸盐化、长石分解蚀变叠加钾硅酸盐化、长石分解蚀变和高岭土化等蚀变.确定了矿化特征、矿物生成顺序并划分了成矿阶段,即:钾硅酸盐阶段、石英硫化物阶段和石英碳酸盐阶段,其中,石英硫化物阶段又可进一步分为石英硫化物亚阶段和绿帘石-绿泥石亚阶段.基于蚀变及矿化特征认为,沙溪铜矿床的矿化始于钾硅酸盐阶段的晚期,石英硫化物亚阶段是黄铜矿主要的沉淀阶段,石英碳酸盐阶段也对成矿贡献了部分铜质.与世界上不同构造环境的典型斑岩铜矿床对比认为,沙溪矿床总体上与这些矿床的蚀变、矿化特征类似;与陆缘弧、岛弧、陆内碰撞造山后伸展环境矿床在矿体产出位置、蚀变分带方面相似;而由于围岩性质的差异,与板内环境的德兴矿床在矿体位置、蚀变分带方面存在差异,但是二者在脉体类型特别是与矿化关系密切的脉体特征上较为一致.因此,对于斑岩型矿床而言,构造背景可能控制了其岩浆的形成、演化以及含矿性,而岩浆岩最终定位的深度、围岩等条件则控制了其蚀变、矿化特征.%Shaxi is a large porphyry copper deposit located outside the Luzong volcanic basin in the Middle and Lower Reaches of the Yangtze River metallogenic belt. Before this study, geological investigations of wall rock alteration and mineralization characteristics of the deposit were minor, restricting application of these guides to exploration and to further study of the metallogenesis of the region. On the basis of previous work

  8. Andean waterways

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    , social, and cultural concerns. Set in the highland town of Recuay in Ancash, the book traces the ways in which water affects political and ecological relations as glaciers recede. By looking at the shared waterways of four villages located in the foothills of Cordillera Blanca, it addresses pertinent......Andean Waterways explores the politics of natural resource use in the Peruvian Andes in the context of climate change and neoliberal expansion. It does so through careful ethnographic analysis of the constitution of waterways, illustrating how water becomes entangled in a variety of political...

  9. Zircon and apatite fission track analyses on mineralization ages and tectonic activities of Tuwu-Yandong porphyry copper deposit in northern Xinjiang, China

    Institute of Scientific and Technical Information of China (English)


    The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different, but also fall into the Hercynian epoch. This study has achieved 9 zircon and 7 apatite fission track analysis results. The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma. The mineralization accords with the regional tectonics in the copper district. We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140-300℃ and retention temperature of ~250℃ for zircon fission track, and metallogenetic temperature of 120-350℃ in this ore district. Total three mineralization epochs have been identified, i.e., 289-276 Ma,232-200 Ma and 165-158 Ma, and indicate occurrence of the mineralization in the Indosinian and Yanshan epochs. Corresponding to apatite fission track ages, the three tectonic-mineralizing epochs are 140-132 Ma, 109-97 Ma and 64 Ma, which means age at about 100℃ after the mineralization. The three epochs lasted 146 Ma, 108 Ma and about 100 Ma from ~250℃ to ~100℃ and trend decrease from early to late. It is shown by the fission track modeling that this district underwent three stages of geological thermal histories, stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.

  10. A deposit scale mineral prospectivity analysis: A comparison of various knowledge-driven approaches for porphyry copper targeting in Seridune, Iran (United States)

    Abedi, Maysam; Mostafavi Kashani, Seyed Bagher; Norouzi, Gholam-Hossain; Yousefi, Mahyar


    In this paper, an application of a knowledge-driven mineral prospectivity mapping (MPM) approach so-called ;the evidential belief functions (EBFs) using Dempster-Shafer's rule of combination; is proposed. This technique is used to weight and integrate a large scale exploration dataset in order to localize prospects for definition of further exploration drilling sites. In this study, exploration datasets of Seridune copper deposit in the Kerman province, SE Iran used for the methodology. In this regard, geophysical evidence layers extracted from interpretation of magnetic and electrical surveys, geological evidence layers derived via the geological datasets (i.e. lithology, fault and alteration), and geochemical evidence maps were generated and integrated for MPM. Furthermore, various MPM approaches including outranking, index overlay and fuzzy logic methods were examined for comparison with the introduced method. To evaluate and compare the efficiency of the methods, the productivity of the drilled boreholes (Cu concentration multiplied by its ore thickness along each drilled borehole) was used to validate the generated prospectivity models. The results showed higher efficiency of the Dempster-Shafer's model in comparison with the prospectivity models generated using other MPM approaches.

  11. Global assessment of undiscovered copper resources (United States)

    U.S. Geological Survey, Department of the Interior — Deposits, prospects, and permissive tracts for porphyry and sediment-hosted copper resources worldwide, with estimates of undiscovered copper resources. pCu_tracts...

  12. Metallogenic age and ore genesis of the Badaguan porphyry copper-molybdenum deposit in Inner Mongolia%内蒙古八大关斑岩型铜钼矿床形成时代与成因分析

    Institute of Scientific and Technical Information of China (English)

    李春风; 柳振江; 宓奎峰; 王建平; 刘瑞斌; 邹君宇; 王忠宝


    八大关铜钼矿床是内蒙古德尔布干成矿带中段的一个典型斑岩型矿床,绢英岩化、青磐岩化等蚀变分带明显,矿体呈条带状赋存于印支期石英闪长岩中。笔者通过运用Re-Os同位素年代学、元素地球化学以及硫同位素等测试手段,初步分析了该矿床的成矿过程。辉钼矿Re-Os同位素加权平均模式年龄为(226.7±2.4) Ma,表明该矿床形成于晚三叠世早期;元素地球化学分析显示含矿岩体属于中钾含量的钙碱性岩石系列,为I型花岗岩,产于火山弧构造环境,具有活动板块边缘的特征,矿化过程中,成矿母岩的稀土元素总量逐渐降低,轻重稀土发生明显分异;金属硫化物的δ34S值介于+0.5‰~+4.8‰,具有幔源硫的特征。综合分析认为八大关铜钼矿床形成于晚三叠世,蒙古-鄂霍茨克洋向南俯冲过程中,深部岩浆活动带来了大量成矿物质,洋壳部分熔融侵位到额尔古纳地块之上,随热液流体迁移的Cu、Mo等元素与源自地幔的硫相结合,最终富集成矿。%Located in the middle of Derbugan metallogenic belt in Inner Mongolia, the Badaguan copper-molybdenum deposit is a typical porphyry deposit with obvious phyllic and propylitic alteration zones. The banded orebodies occur in Triassic quartz diorite. By such means as Re-Os isotope geochronology, element geochemistry and sulfur isotope geochemistry, the authors preliminarily analyzed the ore-forming process of the deposit. Re-Os dating of molybdenite gave a weighted average model age of (226.7 ± 2.4) Ma, implying that the deposit was formed in the early Late Triassic. Element geochemical analysis shows that the ore-bearing rocks were I-type granites and belonged to calc-alkaline rock series with moderate content of potassium, which were produced in a volcanic arc environment with characteristic active plate edges. During the ore-forming process, ΣREE in ore-bearing rock gradually

  13. Geochronology of the Hongniu-Hongshan porphyry and skarn Cu deposit, northwestern Yunnan province, China: Implications for mineralization of the Zhongdian arc (United States)

    Peng, Hui-juan; Mao, Jing-wen; Pei, Rong-fu; Zhang, Chang-qing; Tian, Guang; Zhou, Yunman; Li, Jianxin; Hou, Lin


    The Hongniu-Hongshan porphyry and skarn copper deposit is located in the Triassic Zhongdian island arc, northwestern Yunnan province, China. Single-zircon laser ablation inductively coupled plasma mass spectrometry U-Pb dating suggests that the diorite porphyry and the quartz monzonite porphyry in the deposit area formed at 200 Ma and 77 Ma, respectively. A Re-Os isotopic date of molybdenite from the ore is 78.9 Ma, which indicates that in addition to the known Triassic Cu-(Au) porphyry systems, a Late Cretaceous porphyry Cu-Mo mineralization event also exists in the Zhongdian arc. The quartz monzonite porphyry shows characteristics of a magnetite series intrusion, with a high concentration of Al, K, Rb, Ba, and Pb, low amount of Ta, Ti, Y, and Yb, and a high ratio of Sr/Y (average 26.42). The Cretaceous porphyry also shows a strong fractionation between light and heavy rare earth elements (average (La/Yb)N 37.9), which is similar to those of the Triassic subduction-related diorite porphyry in the Hongniu-Hongshan deposit and the porphyry hosting the Pulang copper deposit. However, in contrast to the older intrusions, the quartz monzonite porphyry contains higher concentrations of large ion lithophile elements and Co, and lesser Sr and Zr. Therefore, whereas the Triassic porphyry Cu-(Au) mineralization is related to slab subduction slab in an arc setting, the quartz monzonite porphyry in the Hongniu-Hongshan deposit formed by the remelting of the residual oceanic slab combined with contributions from subduction-modified arc lithosphere and continental crust, which provided the metals for the Late Cretaceous mineralization.

  14. Palladium, Platinum and Gold Concentrations in Fengshan Porphyry Cu-Mo Deposit, Hubei Province, China

    Institute of Scientific and Technical Information of China (English)

    WANG Minfang; DENG Xiaodong; BI Shijian; LI Zhanke


    The Fengshan porphyry-skarn copper-molybdenum (Cu-Mo) deposit is located in the south-eastern Hubei Province in east China. Cu-Mo mineralization is hosted in the Fengshan granodiorite porphyry stock that intruded the Triassic Daye Formation carbonate rocks in the early Cretaceous (~140 Ma), as well as the contact zone between granodiorite porphyry stock and carbonate rocks, forming the porphyry-type and skarn-type association. The Fengshan granodiorite stock and the immediate country rocks are strongly fractured and intensely altered by hydrothermal fluids. In addition to intense skarn alteration, the prominent alteration types are potassic, phyllic, and propylitic, whereas argillation is less common. Mineralization occurs as veins, stock works, and disseminations, and the main ore minerals are chalcopyrite, pyrite, molybdenite, bornite, and magnetite. The contents of palladium, platinum and gold (Pd, Pt and Au) are determined in nine samples from fresh and mineralized granodiorite and different types of altered rocks. The results show that the Pd content is systematically higher than Pt, which is typical for porphyry ore deposits worldwide. The Pt content ranges from 0.037 tul.765 ppb, and the Pd content ranges between 0.165and 17.979 ppb. Pd and Pt are more concentrated in porphyry mineralization than skarn mineralization, and have negative correlations with Au. The reconnaissance study presented here confirms the existence of Pd and Pt in the Fengshan porphyry-skarn Cu-Mo deposit. When compared with intracontinent and island arc geotectonic settings, the Pd, Pt, and Au contents in the Fengshan porphyry Cu-Mo deposit in the intracontinent is lower than the continental margin types and island are types. A combination of available data indicates that Pd and Pt were derived from oxidized alkaline magmas generated by the partial melting of an enriched mantle source.

  15. Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland (United States)

    Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.


    Lead-isotopic data on galena samples collected from a paragenetically constrained suite of samples from the Silesian-Cracow ore district show no regional or paragenetically controlled lead-isotopic trends within the analytical reproducibility of the measurements. Furthermore, the new lead-isotopic data agree with previously reported lead-isotopic results (R. E. Zartman et al., 1979). Sulfur-isotopic analyses of ores from the Silesian-Cracow district as well as from vein ore from the Gory Swietokrzyskie Mts. and the Myszkow porphyry copper deposit, when coupled with trace-element data from the galena samples, clearly discriminate different hydrothermal ore-forming events. Lead-isotopic data from the Permian and Miocene evaporite deposits in Poland indicate that neither of these evaporite deposits were a source of metals for the Silesian-Cracow district ores. Furthermore, lead-isotopic data from these evaporite deposits and the shale residues from the Miocene halite samples indicate that the crustal evolution of lead in the central and western European platform in southern Poland followed normal crustal lead-isotopic growth, and that the isotopic composition of crustal lead had progressed beyond the lead-isotopic composition of lead in the Silesian-Cracow ores by Permian time. Thus, Mesozoic and Tertiary sedimentary flysch rocks can be eliminated as viable source rocks for the metals in the Silesian-Cracow Mississippi Valley-type (MVT) deposits. The uniformity of the isotopic composition of lead in the Silesian-Cracow ores, when coupled with the geologic evidence that mineralization must post-date Late Jurassic faulting (E. Gorecka, 1991), constrains the geochemical nature of the source region. The source of the metals is probably a well-mixed, multi-cycle molasse sequence of sedimentary rocks that contains little if any Precambrian metamorphic or granitic clasts (S. E. Church, R. B. Vaughn, 1992). If ore deposition was post Late Jurassic (about 150 m. y.) or later

  16. Garnets in porphyry-skarn systems: A LA-ICP-MS, fluid inclusion, and stable isotope study of garnets from the Hongniu-Hongshan copper deposit, Zhongdian area, NW Yunnan Province, China (United States)

    Peng, Hui-juan; Zhang, Chang-qing; Mao, Jing-wen; Santosh, M.; Zhou, Yun-man; Hou, Lin


    The Late Cretaceous Hongniu-Hongshan porphyry-skarn copper deposit is located in the Zhongdian area of northwestern Yunnan Province, China. Garnets from the deposit have compositions that range from Adr14Grs86 to almost pure andradite (Adr98Grs2) and display two different styles of zoning. The garnets are predominantly of magmatic-hydrothermal origin, as is evidenced by their 18Ofluid (5.4-6.9‰) and low Dfluid (-142‰ to -100‰) values, both of which likely result from late-stage magmatic open-system degassing. Three generations of garnet have been identified in this deposit: (1) Al-rich garnets (Grt I; Adr22-57Grs78-43) are anisotropic, have sector dodecahedral twinning, are slightly enriched in light rare earth elements (LREEs) compared with the heavy rare earth elements (HREEs), have negative or negligible Eu anomalies, and contain high concentrations of F. Fluid inclusions within these Al-rich garnets generally have salinities of 12-39 wt.% NaCl eq. and have liquid-vapor homogenization temperatures (Th) of 272-331 °C. The Grt I are most likely associated with low- to medium-salinity fluids that were generated by the contraction of an ascending vapor phase and that formed during diffusive metasomatism caused by pore fluids equilibrating with the host rocks at low W/R (water/rock) ratios. These garnets formed as a result of the high F activity of the system, which increased the solubility of Al within the magmato-hydrothermal fluids in the system. (2) Fe-rich garnets (Adr75-98Grs25-2) have trapezohedral faces, and are both anisotropic with oscillatory zoning and isotropic. These second-generation Fe-rich garnets (Grt II) have high ΣREE concentrations, are LREE-enriched and HREE-depleted, and generally have positive but variable Eu anomalies. All of the Fe-rich garnets contain high-salinity fluid inclusions with multiple daughter minerals with salinities of 33-80 wt.% NaCl eq. Some of them show higher temperatures of halite dissolution (465-591 °C) than

  17. On geological and geochemical features and cause of formation of porphyry copper gold deposit of Shaxi type in Lujiang County, Anhui%安徽沙溪式斑岩铜(金)矿床地质地球化学特征及成因分析

    Institute of Scientific and Technical Information of China (English)

    姚孝德; 陈芳; 王利民; 孙明明


    沙溪斑岩铜(金)矿床位于庐枞火山岩盆地西北外围,处于郯庐断裂带内部.矿体主要产于燕山期的石英闪长斑岩,次为黑云母石英闪长斑岩中.主要成矿期为岩浆期后热液期.蚀变分带自内向外:钠-更长石化带—硬石膏-黑云母-钾硅酸盐化带—钾硅酸盐青磐岩化叠加带—石英绢云母化带—青磐岩化带,主要工业矿体位于钾硅酸盐化带及其外侧.文章总结沙溪式斑岩铜(金)矿床地质地球化学特征,并对该类型铜(金)矿床的成因进行了探讨.%The porphyry copper gold deposit of Shaxi type locates in northwest periphery of Luzong volcanic basin, inside of the Tanlu fault zone. The ore bodies mainly occur in quartz diorite of Yans-hanian, and then in biotite quartzdioriteporphyry. The main metallogenic period is the postmagmatic hydrothermal solution. The alteration zones from the inner to outward are successively the Na-oligo-clase zone, the anhydrite, biotite and K-silicate zone, the superimposed zone of K-silicate and propy-lite, the quartz-sericite zone, and the propylitic zone. The mainly industry ore bodies locate in the K-silicate zone and its outside. The geological and geochemical features of the porphyry copper gold deposit of Shaxi type are summarized, and the cause of the formation of the deposit of this type is discussed.

  18. RS Comprehensive Evaluation for Porphyry Copper in South of Arequipa Province of Peru Based on RS Mine-indicating Information%基于遥感示矿信息的秘鲁阿雷基帕省南部斑岩铜矿遥感综合评价

    Institute of Scientific and Technical Information of China (English)

    杨日红; 陈秀法; 李志忠


    在总结秘鲁南部地区斑岩铜矿成矿地质规律的基础上,分析了研究区控矿构造和赋矿岩层、矿化蚀变类型等成控矿地质特征;并根据研究区斑岩铜矿典型蚀变带蚀变矿物组合及其波谱特征,利用美国地质勘查局(USGS)波谱数据库,重建了斑岩铜矿典型蚀变带主要蚀变矿物在ASTER卫星数据B1~B9对应的反射率曲线,综合对比分析主要蚀变矿物的波谱曲线特征后,研发了基于ASTER数据B1467和B1348主成分分析模型,可分别提取典型蚀变带中泥化—绢英岩化类和青磐岩化蚀变矿物组合信息,并分别提取了研究区泥化—绢英岩化类和青磐岩化带蚀变矿物组合信息,为研究区斑岩型铜矿的遥感综合评价提供了重要的示矿标志;同时,采用人机交互遥感解译技术,获取了斑岩铜矿控矿构造、矿源层与赋矿岩石等示矿信息.最后,基于遥感技术获取的线性与环形控矿构造、矿源层与赋矿岩石、泥化—绢英岩化类和青磐岩化带蚀变矿物组合等遥感示矿信息,完成了研究区遥感找矿综合评价,圈定出遥感找矿有利区,经与已知斑岩铜矿床和物化探资料对比,以及高分辨卫星图像佐证,发现遥感评价结果具有很好的效果.%Based on ore-forming geological regularity of porphyry copper in the south of Arequipa Province,Peru,this essay analyzes the ore-forming and ore-controlling geological features such as ore controlling structure,ore-boring rocks, mineralization and alteration types in the studied area. A set of principal components analysis pattern is developed in which the information of argillic-and phyllic-altered and propylitization altered minerals assemblages in the typical alteration zones can be extracted and studied respectively after making use of spectral data of USGS,reestablishing the reflectivity curve of main altered minerals of the typical alteration zones of porphyry copper which is corresponded

  19. An approach to the metallogenic mechanism of porphyry copper (molybdenum) deposits and porphyry molybdenum (copper) deposits:Influence of evolving processes of ore-forming fluids and tectonic settings%斑岩型铜(钼)矿床和斑岩型钼(铜)矿床的形成机制探讨:流体演化及构造背景的影响

    Institute of Scientific and Technical Information of China (English)

    孙燕; 刘建明; 曾庆栋


    斑岩型铜(钼)矿床和斑岩型钼(铜)矿床是世界钼资源最主要的来源,提供的钼金属量相当。对比发现,两类矿床在流体来源-演化以及铜和钼的相关性上较为相似,而在铜/钼比值、品位、矿物共生组合、蚀变类型等方面存在差异,特别是斑岩铜(钼)矿初始出溶流体中的Cl-/F-值、硫的总量、SO2/H2S以及H+/K+比斑岩钼(铜)矿高。流体演化过程中有两方面因素可能影响最终沉淀的铜和钼比值(1)铜和钼在流体中的性质差异,如铜以氯或硫络合物形式运移,沉淀受温度影响比较显著,钼以羟基或氯络合物形式存在,沉淀受压力控制比较明显;(2)流体自身氧逸度、pH、硫逸度的变化以及演化路径的改变。然而,和初始流体性质的差异相比,流体演化过程对最终形成矿床类型的影响是有限的,决定矿床形成斑岩铜(钼)矿化还是钼(铜)矿化的因素可能在流体出溶之前的岩浆起源-演化阶段就存在。斑岩铜(钼)矿常分布在偏挤压的陆缘弧和大陆碰撞造山带环境,基底多为新生或加厚的陆壳,斑岩钼(铜)矿多出现在偏伸展的陆内裂谷、弧后及造山后伸展环境,基底可以为老陆壳或新生的陆壳;上述特征反映物源区或岩浆的起源和演化方式不同可能是制约形成斑岩铜(钼)矿还是钼(铜)矿的主要机制。%Porphyry Cu-Mo deposits and porphyry Mo-Cu deposits are the most important sources of world's Mo resources,each providing comparable Mo reserves.Although sharing the same characteristics in fluid source and evolution pattern and Cu-Mo correlation,those two types of deposits demonstrate many differences in Cu/Mo ratio,ore grade,mineral association,hydrothermal alteration type,and especially in primitive fluid composition,with fluids from porphyry Cu-Mo deposits containing more sulfur and showing higher ratios of Cl-/F-,SO2/H2S,as well as H+/ K

  20. 西藏雄村斑岩型铜金矿集区Ⅰ号矿体的硫、铅同位素特征及其对成矿物质来源的指示%Sulfur and Lead Isotope Characteristics of No.Ⅰ Ore Body in the Xiongcun Porphyry Copper-Gold Ore Concentration Area of Tibet:Implications for the Source of Metals in the Ore Deposit

    Institute of Scientific and Technical Information of China (English)

    郎兴海; 唐菊兴; 李志军; 黄勇; 丁枫; 王成辉; 张丽; 周云


    The Xiongcun porphyry copper-gold ore concentration area, one of the large-size metallogenic areas discovered along the Gangdise porphyry copper belt, occurs in an island arc environment associated with northward intra-oceanic subduction of Neo-Tethys oceanic crust. The ore-forming age of the Xiongcun porphyry copper-gold ore concentration area is middle Jurassic. It is located in the middle of the southern margin of the Gangdise orogenic belt, and its south margin is Shigatse forearc basin. The latest exploration data indicate that there are several potential mineralization-alteration areas and three large-size copper-gold ore bodies (No. I, II and Ⅲ) in the Xiongcun porphyry copper-gold ore concentration area. In this paper, Xiongcun No. I ore body was chosen as the research object. According to sulfur and lead isotope composition of ore-baring porphyry, tuff and main sulfides of the ore, the authors have reached the following two conclusions: 1) Sulfur isotopic compositions vary in a narrow range of δ34S values from -3.5‰ to +2.7‰ (-1.07‰ on average) and are close to zero, indicating a mantle sulfur signature. 2) They have uniform Pb isotope compositions with low content of radiogenic Pb. The 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios vary in the ranges of 18.104-18.432, 15.473-15.533 and 37.918-38.3072, respectively. They are located in the transition zone of mantle Pb and orogen Pb but are closer to the former, reflecting a mixing between the mantle material and minor crust material. Through a comparative study of sulfur and lead isotopes of porphyry copper deposits of the island arc environment (e.g., Xiongcun No. I ore body) and those of the collisional orogenic environment in the Gangdise porphyry copper belt, the authors found that they have similar metal sources, but porphyry copper deposits of the island arc environment have experienced weak contamination of crust materials, whereas porphyry copper deposits of the coilisional orogenic

  1. The Indo-Chinese Epoch Arc Magmatism of Geza Island-Arc and Porphyry Copper Mineralization in Pulang Sanjiang Orogenic Belt, Southwest China%云南省格咱岛弧印支期岩浆演化及普朗斑岩型铜矿成矿作用

    Institute of Scientific and Technical Information of China (English)

    刘学龙; 李文昌; 尹光侯; 张娜


    Geza island arc located in the southern of Yidun arc of southwest Sanjiang tectonic igneous rock belts in China, it was the result that Ganzi-Litang oceanic crust dived to the Zhongdian Landmasses in late Triassic. The belt is an important discovered copper-polymetallic metallogenic belt in the recent years in China. The regional strong tectonic-magmatic activity runs through the orogenesis of island arc, the rich mineralization developed in the different times and different circumstances of island arc orogenesis, where outputed the large sized Pulang and Xuejiping porphyry-related copper polymetallic deposit. The Pulang porphyry copper deposits is a typical representative of Indosinian porphyry copper deposits, the ore-bearing porphyry SiO2 content in 60. 07% ~65. 78%, it belongs to the neutral-acid rocks. A12O3content is 14. 80% ~ 15.97%, (K2O+Na2O) is 5. 79% ~10. 99% , K2O/Na2O is 0.7 ~ 1.14, Rittmann index (σ) is 1.02 ~ 1. 9, Consolidation index (SI) is in the range of 7. 65 — 24. 77, Differentiation index (DI) is in the range of 61. 17 ~ 70. 58, so the rocks belong to calc-alkaline rocks series and have the better magma differentiation. A/CNK values in 0. 74~0. 981, average of 0. 87, rocks belong to prospective aluminous granits. Zircon U-Pb dating results show that the quartz diorite formation age was 220. 8 ± 4. IMa, the quartz monzonite porphyry formation age was 214. 8±3. 5Ma, porphyries rocks metallogenic epoch is mainly concentrated in the Indosinian.%格咱岛弧位于西南三江构造火成岩带义敦岛弧南端,是晚三叠世甘孜-理塘洋壳向德格-中甸陆块俯冲的产物,是我国近年来新发现的重要铜多金属成矿带.该区强烈的构造-岩浆活动贯穿于岛弧造山作用的始终,丰富的成矿作用发育于岛弧造山的不同时代、不同环境,产出了普朗、雪鸡坪等大型铜多金属矿床.其中普朗斑岩型铜矿是印支期斑岩铜矿的典型代表,其含矿斑岩体SiO2

  2. Features and evolution of metallogenic fluid in Jiadanggen porphyry copper deposit of Gonghe Country, Qinghai Province%青海共和县加当根斑岩铜矿床成矿流体特征及演化

    Institute of Scientific and Technical Information of China (English)

    于淼; 丰成友; 肖晔; 刘建楠; 李大新; 李国臣; 马圣钞


    加当根矿床是近几年新发现的研究程度较低的斑岩型铜矿床,文章对含矿斑岩、石英脉和绢英中的石英岩开展了详细的流体包裹体特征及氢、氧同位素组成研究.该矿床流体包裹体类型丰富,以大量发育含子晶多相包裹体为特征,子矿物种类多样,包括石盐、钾盐、石膏、黄铜矿、黄铁矿、赤铁矿等.石膏、赤铁矿的出现,暗示着岩浆结晶早期处于氧化环境.成矿流体由来自岩浆的高温、高盐度流体和以天水成因为主的中-高温、低盐度流体2个端员组分组成,高温、高盐度流体为主要载矿流体,形成温度> 440℃,w(NaCleq)为30%~82%,其是在浅成条件下于岩浆结晶的最后阶段从浅部岩浆中直接出溶形成的;中-高温、低盐度流体主要来源于天水或天水与晚期岩浆热液的混合,温度主要集中在220~360C,w(NaCleq)< 20%.石英流体包裹体氢、氧同位素研究表明流体混合在卸载成矿上的重要性,石英脉和绢英岩化阶段是含矿物质沉淀的主要阶段.脉石英的流体温度集中在280~440℃,绢英岩化蚀变石英中流体包裹体的均一温度介于240~340℃.%The Jiadanggen porphyry copper deposit was discovered in recent years, but its research is very insufficient. This paper mainly deals with the homogenization temperature of fluid inclusions and the evolution tendency of ore-forming fluid. The fluid inclusions in the pluton and quartz veins are characterized by abundantly daughter minerals-bearing inclusions in which daughter minerals composed of halite, sylvite, gypsum, chalcopyrite, pyrite and hematite. The presence of gypsum and hematite imply oxidation environment at the early stage of magmatic crystallization. The microthermometric analysis of inclusions reveals that the metallogenic fluid consists of both high-temperature, hypersaline fluids and medium-low temperature, low salinity ones. High temperature, hypersaline fluids

  3. ASTER数据的斑岩铜矿典型蚀变矿物组合信息提取方法——以秘鲁南部阿雷基帕省斑岩铜矿区为例%Information Extraction of Typical Alteration Mineral Assemblage in Porphyry Copper Using ASTER Satellite Data, Arequipa Province of South Peru

    Institute of Scientific and Technical Information of China (English)

    杨日红; 李志忠; 陈秀法


    In this paper we studied the information extraction technology of alteration mineral assemblages. Using the standard laboratory spectral database of U. S. Geological Survey, we rebuilt the reflectivity curve of key alteration minerals in porphyry copper alteration zones with ASTER data. After comparative analysis of these key alteration minerals spectral curves, we found the characteristic of absorption valley at the spectral 2. 2μm (which is corresponding to the B6 of ASTER data) of the argillic- and phyllic-altered mineral assemblage (which include muscovite, kaolinite, montmorillonite, alunite, illite, etc. ) , and with the characteristic of high reflection peaks at B4 and B7. The characteristic of absorption valley at the spectral 2. 3 μm (which is corresponding to the B8 of ASTER data) of the propylitization altered mineral assemblage (which include chlorite, epidote, calcite, etc. ,), and with the characteristic of a high reflection peaks at B4, while the B9 has a higher reflectivity than the B8. Accordingly, the principal component analysis model was developed. This model can make component analysis based on ASTER Bl, B4, B6 and B7 to extract the argillic- and phyllic-altered mineral assemblage; component analysis based on ASTER Bl, B3, B4 and B8 to extract propylitization altered mineral assemblage. At the same time, the process was established for the alteration mineral assemblage information extraction. Taking porphyry copper region in Arequipa Province of south Peru as an example, based on comprehensive analysis of the geological background of the study area, especially its typical alteration zoning and alteration mineral assemblages in the area, we found a typical porphyry alteration zonation in Arequipa Province. So we can take advantage of the technical processes and methods, and after ASTER data preprocessing, interfering surface features removal, principal component analysis and threshold setting, to extract argillic- and phyllic-altered mineral

  4. 广西大黎铜钼矿石英二长(斑)岩年代学、地球化学特征及其地质意义%Chronology and Geochemical Characteristics of Quartz Monzonite (Porphyry) in the Dali Copper-Molybdenum Deposit and Its Geological Significance

    Institute of Scientific and Technical Information of China (English)

    胡升奇; 周国发; 彭松柏; 张先进; 易顺华; 唐国胜


    conditions of mineralization and inferred the porphyry copper-molybdenum mineralization age. The main favorable ore-forming conditions lie in the following three aspects: ?I-type quartz monzonite (porphyry) is a good parent rock for mineralization; ?The ore district has relatively high background values of Cu, Mo, Pb, Sn ore-forming elements; ?Deep fault and #-shaped fault system of the study area constitute a favorable ore-controlling tectonic background. A comprehensive analysis shows that the ore-forming age of the Dali copper-molybdenum deposit should be late Early Cretaceous, consistent with the diagenetic age of about 100 Ma.%大黎石英二长(斑)岩岩体出露于广西壮族自治区大瑶山地区藤县大黎镇南部一带,LA-ICP-MS测得石英二长岩和石英二长斑岩的U-Pb年龄分别为(102.8±0.9) Ma和(101.7±1.2) Ma.岩体SiO2含量为60.09%~62.91%,Na2O和CaO的含量分别为2.90%~3.08%,3.32%~4.35%,A/CNK=0.83~0.93,均小于1.0,100Fe3+/(Fe3++Fe2+)的值为37.76~42.93,里特曼指数σ变化范围为2.94~3.07,属于钙碱性、准铝质花岗岩系列.稀土元素总体显示轻稀土元素富集,轻、重稀土元素分馏明显,总体呈具有弱Eu异常右倾的稀土配分模式.微量元素总体显示相对富集Rb、Th、U、K、La、Ce、Pb等大离子亲石元素,亏损Nb、Ta、P、Ti等高场强元素.综合分析表明,大黎石英二长(斑)岩为壳幔混合源Ⅰ型花岗岩;结合区域构造演化历史,认为大黎石英二长(斑)岩是燕山晚期早白垩世晚期后碰撞阶段张性构造环境的产物,与印度板块在该时期北移所引起的古太平洋板块高角度俯冲所导致的弧后拉张有关.通过论述区域构造演化,探讨该岩体的基本属性、成因、形成环境,分析了有利成矿条件:①Ⅰ型石英二长(斑)岩为有利的成矿母岩;②矿区具有相对较高的Cu、Mo、Pb、Sn成矿元素背景值;③研究区的深大断裂和井字形断裂系统是控

  5. An Introduction to Copper Deposits in China

    Institute of Scientific and Technical Information of China (English)


    There are 11 genetic types of copper deposit in China, three of which (porphyry,contact metasomatic and VMS types) are the most important. The copper deposits distribute widely both temporally and spatially in China. The features of copper ores in China are mostly poor in copper tenor and complex in metal associated. The copper metallogeny in China predominantly occurs in three metallogenic megadomains, namely the circum-Pacific, the paleo-Asian and the Tethys-Himalayan.

  6. Geochemical Trace of Silicon Isotopes of Intrusions and Ore Veins Related to Alkali-rich Porphyry Deposits in Western Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    LIU Xianfan; YANG Zhengxi; LIU Jiaduo; WU Dechao; ZHANG Chenjiang; LI Youguo


    Western Yunnan is the well-known polymetallic province in China. It is characterized by copper-gold mineralization related to Cenozoic alkali-rich porphyry. This paper analyzes the silicon isotope data obtained from four typical alkali-rich porphyry deposits based on the dynamic fractionation principle of silicon isotope. The study shows that the ore materials should originate mainly from alkali-rich magmas, together with silicon-rich mineralizing fluids.The process of mineralization was completed by auto-metasomatism, i.e. silicon-rich mineralizing fluids (including alkali-rich porphyry and wall-rock strata) replaced and altered the country rocks and contaminated with crustal rocks during the crystallization of alkali-rich magmas. Such a process is essentially the continuance of the metasomatism of mantle fluids in crust's mineralization. This provides important evidence of silicon isotopic geochemistry for better understanding the mineralization of the Cenozoic alkali-rich porphyry polymetallic deposits

  7. Qochas on Andean highlands

    CERN Document Server

    Sparavigna, Amelia Carolina


    On the Andean highlands, the "qochas" are lakes or ponds of natural or artificial origin. An ancient agricultural technique is based on their use. Linked together by a network of canals, qochas form a system of water and soil management, alternately used for crops or pasture. The concave structure of qochas controls the strong evaporation produced by solar radiation and wind blowing. Qochas can be observed in the satellite imagery of Google Maps.

  8. Porphyry of Russian Empires in Paris (United States)

    Bulakh, Andrey


    Porphyry of Russian Empires in Paris A. G. Bulakh (St Petersburg State University, Russia) So called "Schokhan porphyry" from Lake Onega, Russia, belongs surely to stones of World cultural heritage. One can see this "porphyry" at facades of a lovely palace of Pavel I and in pedestal of the monument after Nicolas I in St Petersburg. There are many other cases of using this stone in Russia. In Paris, sarcophagus of Napoleon I Bonaparte is constructed of blocks of this stone. Really, it is Proterozoic quartzite. Geology situation, petrography and mineralogical characteristic will be reported too. Comparison with antique porphyre from the Egyptian Province of the Roma Empire is given. References: 1) A.G.Bulakh, N.B.Abakumova, J.V.Romanovsky. St Petersburg: a History in Stone. 2010. Print House of St Petersburg State University. 173 p.

  9. Mo isotope fractionation during hydrothermal evolution of porphyry Cu systems (United States)

    Shafiei, Behnam; Shamanian, GholamHossein; Mathur, Ryan; Mirnejad, Hassan


    We present Mo isotope compositions of molybdenite types from three successive stages of ore deposition in several porphyry copper deposits of the Kerman region, Iran. The data provide new insights into controlling processes on Mo isotope fractionation during the hydrothermal evolution of porphyry systems. The Mo isotope compositions of 27 molybdenite samples show wide variations in δ97Mo ranging from -0.37 to +0.92 ‰. The data reveal that molybdenites in the early and transitional stages of mineralization (preferentially 2H polytypes; δ97Mo mean = 0.35 ‰) have higher δ97Mo values than late stage (mainly 3R polytypes; δ97Mo mean = 0.02 ‰) molybdenites. This trend suggests that fractionation of Mo isotopes occurred in high-temperature stages of mineralization and that hydrothermal systems generally evolve towards precipitation of molybdenite with lower δ97Mo values. Taking into account the genetic models proposed for porphyry Cu deposits along with the temperature-dependent fractionation of Mo isotope ratios, it is proposed that large variations of Mo isotopes in the early and the transitional stages of ore deposition could be controlled by the separation of the immiscible ore-forming fluid phases with different density, pH, and ƒO2 properties (i.e., brine and vapor). The fractionation of Mo isotopes during fluid boiling and Rayleigh distillation processes likely dominates the Mo isotope budget of the remaining ore-forming fluids for the late stage of mineralization. The lower δ97Mo values in the late stage of mineralization can be explained by depletion of the late ore-forming hydrothermal solutions in 97Mo, as these fluids have moved to considerable distance from the source. Finally, the relationship observed between MoS2 polytypes (2H and 3R) and their Mo isotopic compositions can be explained by the molecular vibration theory, in which heavier isotopes are preferentially partitioned into denser primary 2H MoS2 crystals.

  10. Andean region study

    Energy Technology Data Exchange (ETDEWEB)



    New opportunities for climate change mitigation arising from a higher energy integration among Andean Pact nations were analysed within the framework of the UNEP/GEF Project. Apart from the search for regional mitigation actions, the study was mainly aimed at detecting methodological problems which arise when passing from a strictly national view to the co-ordination of regional actions to deal with climate change. In accordance with the available resources and data, and in view of the mainly methodological nature of the project, it was decided to analyse the opportunities to delve into the energy integration of the Region as regards electricity and natural gas industries and their eventual impact on the emission of greenhouse gases. Although possibilities of setting up electricity and natural gas markets are real, their impacts on GHG emission from the energy system would not prove substantially higher than those which the nations could achieve through the use of their own energy resources, in view that the Andean systems are competitive rather than complementary. More in-depth studies and detail information will be required - unavailable for the present study - to be able to properly evaluate all benefits associated with higher energy integration. Nevertheless, the supply of natural gas to Ecuador seems to be the alternative with the highest impact on GHG emission. If we were to analyse the supply and final consumption of energy jointly, we would most certainly detect additional mitigation options resulting from higher co-operation and co-ordination in the energy field. (EHS)

  11. 西藏雄村铜金矿Ⅰ号矿体赋矿凝灰岩成因探讨:来自岩石地球化学、Sr-Nd-Pb同位素地球化学特征的证据%The Genesis of Mineralized Tuff of No.Ⅰ Ore Body in the Xiongcun Porphyry Copper-Gold Metallogenic Ore District, Tibet: Evidence from Geochemistry and Sr-Nd-Pb Isotopes

    Institute of Scientific and Technical Information of China (English)

    丁枫; 郎兴海; 胡正华; 杨欢欢; 王子正; 张丽


    雄村斑岩型铜金矿集区位于冈底斯造山带中段南缘,目前发现的Ⅰ、Ⅱ、Ⅲ号主矿体均产于含矿斑岩体及其接触带附近的凝灰岩中,本文主要对雄村Ⅰ号矿体赋矿凝灰岩开展岩石地球化学特征研究.赋矿凝灰岩显示出与岛弧火山岩相似的地球化学特征,如相对富集LREE、LILE而亏损HREE、HFS以及低的I(sr)值(变化范围为0.704163~0.705369,均值0.704907)和正的εNd(t)值(变化范围为3.7805~7.6286,均值5.904121)等,其形成与印度-亚洲大陆碰撞造山之前的新特提斯洋俯冲作用有关,产于新特提斯洋向北的洋内俯冲作用而形成的岛弧环境.赋矿凝灰岩起源于岛弧底部的新生玄武质岩层的部分熔融,源岩主要由角闪石、斜长石和少量石榴子石组成.赋矿凝灰岩、含矿斑岩体和成矿作用同属一个火山-岩浆-热液系统,赋矿凝灰岩为成矿提供了必要的围岩外部因素,是矿区重要的控矿因素,也是一个重要的找矿地质条件.在雄村矿区及其外围,侵位于凝灰岩中的斑岩体应该是今后找矿评价的重点区域.%The Xiongcun porphyry copper-gold metallogenic ore concentration area is located in the north of the middle Gangdise orogenic belt. No. Ⅰ, Ⅱ and Ⅲ main ore bodies of Xiongcun area are hosted in ore-bearing porphyries and tuff along the contact zone. This paper mainly studied geochemistry of mineralized tuff in Xiongcun No. I ore body. The mineralized tuff is similar to volcanic rocks in island arc in such geochemical characteristics as relative enrichment of LREE and LILE, depletion of HREE and HFS, low I(Sr) values (raning from 0.704163 to 0.705369, 0.704907 on average), and positive εNd(t) values (ranging from 3.7805~7.6286, 5.904121 on average). Mineralized tuff was formed in an island arc environment and was related to northwards subduction of the Neo-Tethys Ocean which occurred before India - Asian continental collision, and its source

  12. Geology,Geochemistry and Genesis of Yinyan Porphyry Tin Deposit

    Institute of Scientific and Technical Information of China (English)

    朱正书; 朱金初; 等


    The Yinyan porphyry tin deposit is a blind deposit associated with a small granite porphyry stock.The petrology and geochemistry of the Yinyan granite porphyry suggest that it is genetically of the transfor-mation type,emplaced at the late stage of fractional crystallization within a high-level magma chamber.Ore-forming fluids are derived predominantly from the granitic magma and they interact with the wall rocks intensely when finding their way upwards through the granite porphyry.From the lower part of the porphyry upwards the following alteration zones can be distinguished(a)slightly altered granite porphyry (with weak potash feldspathization),(b)protolithionite-quartz greisenization zone,(c)to-paz-quartz greisenization zone,(d)senicite-quartz sericitization zone,and (e)silicification zone (quartz core at the surface).Tin mineralization is related to greisenization,especially to topaz-quartz greisenization.Rock and ore-forming temperatures and oxygen fugacities are estimated,respectively.There are significant differences in many aspects between the Yinyan porphyry tin deposit and volcan-ic-subvolcanic porphyry tin deposits.

  13. Geological analysis of aeromagnetic data from southwestern Alaska: implications for exploration in the area of the Pebble porphyry Cu-Au-Mo deposit (United States)

    Anderson, Eric D.; Hitzman, Murray W.; Monecke, Thomas; Bedrosian, Paul A.; Shah, Anjana K.; Kelley, Karen D.


    Aeromagnetic data are used to better understand the geology and mineral resources near the Late Cretaceous Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska. The reduced-to-pole (RTP) transformation of regional-scale aeromagnetic data shows that the Pebble deposit is within a cluster of magnetic anomaly highs. Similar to Pebble, the Iliamna, Kijik, and Neacola porphyry copper occurrences are in magnetic highs that trend northeast along the crustal-scale Lake Clark fault. A high-amplitude, short- to moderate-wavelength anomaly is centered over the Kemuk occurrence, an Alaska-type ultramafic complex. Similar anomalies are found west and north of Kemuk. A moderate-amplitude, moderate-wavelength magnetic low surrounded by a moderate-amplitude, short-wavelength magnetic high is associated with the gold-bearing Shotgun intrusive complex. The RTP transformation of the district-scale aeromagnetic data acquired over Pebble permits differentiation of a variety of Jurassic to Tertiary magmatic rock suites. Jurassic-Cretaceous basalt and gabbro units and Late Cretaceous biotite pyroxenite and granodiorite rocks produce magnetic highs. Tertiary basalt units also produce magnetic highs, but appear to be volumetrically minor. Eocene monzonite units have associated magnetic lows. The RTP data do not suggest a magnetite-rich hydrothermal system at the Pebble deposit. The 10-km upward continuation transformation of the regional-scale data shows a linear northeast trend of magnetic anomaly highs. These anomalies are spatially correlated with Late Cretaceous igneous rocks and in the Pebble district are centered over the granodiorite rocks genetically related to porphyry copper systems. The spacing of these anomalies is similar to patterns shown by the numerous porphyry copper deposits in northern Chile. These anomalies are interpreted to reflect a Late Cretaceous magmatic arc that is favorable for additional discoveries of Late Cretaceous porphyry copper systems in southwestern

  14. Brecha de turmalina del pórfido de cobre-oro San Jorge, Mendoza: alteración, mineralización y origen de los fluidos Tourmaline breccia of San Jorge porphyry copper gold deposit (Mendoza: alteration, mineralization and origin of the fluids

    Directory of Open Access Journals (Sweden)

    Mirta M. Garrido


    Full Text Available La brecha de turmalina (breccia pipe asociada al pórfido de cobre oro San Jorge está desarrollada en las sedimentitas carboníferas (Formación Yalguaráz ubicada en el contacto con el margen SO del cuerpo de granodiorita (Pérmico. Es clasto sostén y monomíctica (arenisca, con escasa matriz y cemento principalmente de turmalina. La intensidad del brechamiento disminuye hasta alcanzar un stockwork y una zona de menor densidad de venillas en la base. La alteración hidrotermal se manifiesta como un reemplazo de la roca y un relleno de fracturas. Presenta una primera alteración potásica y se sobreimpone una fílica que predomina en las partes medias y altas del cuerpo. Como relleno de las fracturas, se presentan turmalina, feldespato potásico, sericita, pirita y calcopirita, y es donde se registran las leyes más altas de cobre del depósito. Fracturas posteriores a la brecha están vinculadas a venillas de cuarzo y sericita, de sericita y de cuarzo, pirita, calcopirita y arsenopirita. Un primer fluido relacionado a la alteración potásica es sobresaturado en sales y no presenta ebullición; el otro relacionado al evento de alteración fílica es de baja salinidad y manifiesta ebullición a 400ºC. Considerando un sistema hidrostático, se estimó una profundidad de formación para la brecha de 1,5 km. Los valores isotópicos calculados de δ18O entre 8,45 y 9,75 ‰ y de δ D entre -53,07 y -63,07 ‰ sobre turmalina indican una fuente magmática para los fluidos. Desde el punto de vista genético, y sustentado por las evidencias de texturas, inclusiones fluidas e isótopos, se clasifica como una brecha hidrotermal magmáticaThe tourmaline breccia (breccia pipe associated to San Jorge porphyry copper ore deposit is developed in carboniferous sedimentites (Yalguaráz Formation at the contact with the SW margin of a permian granodiorite. The breccia is clast supported and monomictic (sandstone, with scarce matrix and cement mainly composed

  15. Element geochemical characteristics of No.Ⅱ ore body of the Xiongcun porphyry copper-gold deposit in Tibet%西藏雄村斑岩铜金矿床Ⅱ号矿体元素地球化学特征及其指示意义

    Institute of Scientific and Technical Information of China (English)

    黄勇; 唐菊兴; 丁俊; 郎兴海; 李志军; 张丽


    雄村铜金矿是冈底斯成矿带上新发现的岛弧型斑岩铜金矿床,矿床由3个矿体组成,Ⅱ号矿体位于Ⅰ号矿体北西侧3km处.Ⅱ号矿体中铜、金、银矿化主要分布在早期钾-硅酸盐化带以及绢云母白云母-石英硫化物带中,早期钾-硅酸盐化的典型矿物组合为黑云母+磁铁矿±钾长石+黄铜矿+黄铁矿,热液磁铁矿含量较高.元素空间分布特征以及相关性分析表明,Cu和Au、Ag呈显著正相关,黄铜矿是Au和Ag的主要载体,分布在矿体中心.Cu与K、Rb呈正相关,而与Na呈负相关的特点表明矿化与钾质交代关系密切,晚期矿化以分布在外围的细脉状、脉状方铅矿和闪锌矿化为主.由矿体中心向外,与矿化有关的16种元素构成Cu、Au、Ag、K、Rb、Ba-Mo-Co、Ni-Pb、Zn、Mn、Ag、Sb-Na元素分带,元素带状分布特征与蚀变矿化分带吻合.分布在外围的Na同时受钾质交代过程中Na元素向外迁移作用以及早期深部高温环境下的钠质-钙质蚀变共同控制.元素空间分带特征与蚀变与矿化分带机理类似,受热液流体演化、运移、温压条件和原岩组分等综合因素控制,分带特征对今后的找矿与勘探工作具有一定的指示意义.%The Xiongcun copper-gold deposit is an island arc porphyry copper-gold deposit newly discovered in the Gangdise metallogenic belt. It consists of three ore bodies. No. Ⅱ ore body is located 3 km northwest of No. I ore body. Cu, Au, and Ag mineralizations occur in early K-silicate alteration zone and sericite-muscovite-quartz-sulphide zone. Early K-silicate alteration is characterized by biotite + magnetite ± K-feldspar + chalcopy-rite+ pyrite, and is rich in magnetite. Element distribution characteristics and correlation analysis show that Cu is well correlated to Au and Ag. Au- and Ag-bearing chalcopyrite is mainly distributed at the center of the ore deposit. Cu is positively related to K, Rb and negatively related to Na

  16. Climax-Type Porphyry Molybdenum Deposits (United States)

    Ludington, Steve; Plumlee, Geoffrey S.


    Climax-type porphyry molybdenum deposits, as defined here, are extremely rare; thirteen deposits are known, all in western North America and ranging in age from Late Cretaceous to mainly Tertiary. They are consistently found in a postsubduction, extensional tectonic setting and are invariably associated with A-type granites that formed after peak activity of a magmatic cycle. The deposits consist of ore shells of quartz-molybdenite stockwork veins that lie above and surrounding the apices of cupola-like, highly evolved, calc-alkaline granite and subvolcanic rhyolite-porphyry bodies. These plutons are invariably enriched in fluorine (commonly >1 percent), rubidium (commonly >500 parts per million), and niobium-tantalum (Nb commonly >50 parts per million). The deposits are relatively high grade (typically 0.1-0.3 percent Mo) and may be very large (typically 100-1,000 million tons). Molybdenum, as MoS2, is the primary commodity in all known deposits. The effect on surface-water quality owing to natural influx of water or sediment from a Climax-type mineralized area can extend many kilometers downstream from the mineralized area. Waste piles composed of quartz-silica-pyrite altered rocks will likely produce acidic drainage waters. The potential exists for concentrations of fluorine or rare metals in surface water and groundwater to exceed recommended limits for human consumption near both mined and unmined Climax-type deposits.

  17. Geological and geochemical studies of the Shujiadian porphyry Cu deposit, Anhui Province, Eastern China: Implications for ore genesis (United States)

    Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; White, Noel C.; Lin, Fengjie


    Most porphyry deposits in the world occur in magmatic arc settings and are related to subduction of oceanic plates. A small proportion of porphyry deposits occur in intracontinental settings, however they are still poorly understood. Shujiadian, a newly-discovered porphyry Cu deposit, is located in the Middle-Lower Yangtze River Valley metallogenic belt and belongs to the intracontinental class. The deposit has classic alteration zones defined by a core of potassic alteration and local Ca-silicate alteration, which is overprinted by a feldspar-destructive alteration zone and cut by veins containing epidote and chlorite. Wallrocks of the deposit are unreactive quartz-rich sedimentary rocks. Three main paragenetic stages have been recognized based on petrographic observations; silicate stage, quartz-sulfide stage, and sulfide-carbonate stage. Quartz + pyrite + chalcopyrite ± molybdenite veins, and quartz + chalcopyrite + pyrite veins of the quartz-sulfide stage contribute most of the copper, and chalcopyrite + chlorite ± pyrite ± pyrrhotite ± quartz ± illite veins of the sulfide-carbonate stage also contribute part of the copper; all the mineralized veins are associated with feldspar-destructive alteration. Investigations on the fluid inclusions in Shujiadian indicate that the ore-forming fluids had four evolutionary episodes: immiscibility and overpressure in the silicate stage, boiling in the quartz-sulfide stage and mixing with meteoric water in the sulfide-carbonate stage. Sulfur and strontium isotope studies suggest that ore metals were mainly derived from magmatic-hydrothermal fluids, and combined with our study of fluid inclusions, we infer that decompression, changes in oxygen fugacity and sulfur content were the main factors that caused Cu precipitation. Compared with porphyry deposits in magmatic arc settings, there are some differences in the ore-bearing rock, alteration, and the composition of ore-forming fluids.


    Institute of Scientific and Technical Information of China (English)

    LIU Xianfan; YANG Zhengxi; LIU Jiaduo; ZHANG Chengjiang; WU Dechao; LI Youguo


    Ultramafic hypoxenoliths found in the alkali-rich porphyry in the Liuhe Village, Heqing, Yunnan,China, are of great significance in understanding the origin and evolution of the porphyry. This paper discusses the mineralogical features of the hypoxenoliths. It shows that the xenoliths are characterized by the upper mantle rocks modified to certain extent by the enriched mantle fluid metasomatism in the mantle environment, with the enriched mantle property of Iow-degree partial melting. This constitutes the important mineralogical evidence for the petrogenesis and mineralization of alkali-rich porphyry.

  19. The Dala (Älvdalen) Porphyries from Sweden (United States)

    Wikström, Anders; Pereira, Lola; Lundqvist, Thomas; Cooper, Barry


    The Dala (Älvdalen) Porphyries from Sweden Anders Wikström (retired from Geological Survey of Sweden) Lola Pereira (University of Salamanca, Spain) Thomas Lundqvist (retired from Geological Survey of Sweden) Barry Cooper (University of South Australia) The commercial stone industry in Älvdalen, about 350 km northwest of Stockholm, commenced in the second half of the 18th century, as a consequence of social need. The region had been plagued by severe famine and there was an urgent need for additional wealth-generating industry. At that time it was already known that the porphyry in the area was similar to the "porfido rosso antico" from Egypt which had played an important role in the Roman culture. Many ups and downs followed. During one period in the 19th century, the Swedish Royal family owned the industry. At the same time, several "porphyry" objects were presented to different courts around Europe (e.g. a 4 metre tall vase to the Russian czar, although of a more granitic variety). Otherwise most products have been smaller objects like urns, vases, candelabras, etc. The very hard stone (with variable red or black colours) can be highly polished. Many of the porphyry varieties were sourced from glacial boulders. These had been "mechanically tested" by nature and were free from joints which otherwise was a problem in the associated quarries. Comagmatic granites also occur. The porphyries and granites have an age around 1700 Ma, and the former are amazingly well preserved with magnificent volcanic textures. The porphyries and granites occupy a vast area and are in part covered with red, continental sandstones (which are quarried to-day). In the middle of the 20th century, the ignimbritic character of the porphyry was discovered. Previously, the flattened "fiamme" (collapsed pumice) had been interpreted as some kind of flow structure in a lava. The porphyry manufacturing plants in Älvdalen are a part of the Swedish industrial history. Over a significant

  20. Petrology, Geochemistry and Petrogenesis of Wolonggu granites and Tongchang granodioritic porphyries: Constraints on copper metallogenic geological settings in northeastern Jiangxi Province%江西卧龙谷花岗岩和铜厂花岗闪长斑岩的地球化学特征及成因——对赣东北地区铜矿成矿地质背景的制约

    Institute of Scientific and Technical Information of China (English)

    郭博然; 刘树文; 杨朋涛; 王宗起; 罗平; 王永庆; 罗国辉; 王伟


    Northeastern Jiangxi Province is a major polymetallic ore-forwing area in northeastern segment of the Jiangnan orogenic belt.Wolonggu granitoid pluton is a typical nonmineralized granite pluton and consists chiefly of monzogranites.LA-ICP-MS zircon U-Pb isotopic dating yields a weighted mean 206Pb/238U age of 133Ma±1Ma,which represents the age ofmagrnatic crystallization and reveals that the granitic pluton was emplaced in Early Cretaceous.Combined with their high initial 87Sr/865r values ranging from 0.716079 to 0.719392 and low εNd(t) values ranging from-6.51 to-5.14,the authors hold that the Wolonggu granites were probably derived from partial melting of metamorphic pelitic rocks from the crustal source region.However,Tongchang granodioritic porphyric intrusion is a classic mineralized granitic pluton and consists mainly of granodioritic porphyries.Emplaced in Middle Jurassic (with crystallization age of 171Ma±3Ma),the Tongchang granodioritic porphyries display low initial87Sr/86Sr values ranging from 0.704403 to 0.704475,high εNd (t) values ranging from-1.14 to ±1.80 and higher Mg# values of 28-53,suggesting that the magma was possibly derived from partial melting of subducted oceanic slabs and relative sediments,and was polluted by mantle materials during its upward migration.The comparison of features between the nonmineralized granite pluton and the copper mineralized granitic pluton can detect the constraint of the Mesozoic granitoid magmatism on copper metallogenic geological settings,which may provide the essential geological data of the geodynamic setting for regional mineralization.%赣东北地区是江南造山带东北段重要的多金属成矿区.卧龙谷花岗岩体是典型的非铜矿成矿花岗岩体,由二长花岗岩组成,其LA-ICP-MS锆石U-Pb同位素分析揭示其岩浆结晶年龄为133 Ma±1Ma,形成于早白垩世.这些岩石表现出高的初始87Sr/86Sr比值(0.716079~ 0.719392)和较低的εNd(t)(-6.51~-5.14)值,指示

  1. Hydrothermal Fluid evolution in the Dalli porphyry Cu-Au Deposit: Fluid Inclusion microthermometry studies

    Directory of Open Access Journals (Sweden)

    Alireza Zarasvandi


    Full Text Available Introduction A wide variety of world-class porphyry Cu deposits occur in the Urumieh-Dohktar magmatic arc (UDMA of Iran.The arc is composed of calc-alkaline granitoid rocks, and the ore-hosting porphyry intrusions are dominantly granodiorite to quartz-monzonite (Zarasvandi et al., 2015. It is believed that faults played an important role in the emplacement of intrusions and subsequentporphyry-copper type mineralization (Shahabpour, 1999. Three main centers host the porphyry copper mineralization in the UDMA: (1 Ardestan-SarCheshmeh-Kharestan zone, (2 Saveh-Ardestan district; in the central parts of the UDMA, hosting the Dalli porphyry Cu-Au deposit, and (3 Takab-Mianeh-Qharahdagh-Sabalan zone. Mineralized porphyry coppersystems in the UDMA are restricted to Oligocene to Mioceneintrusions and show potassic, sericitic, argillic, propylitic and locally skarn alteration (Zarasvandi et al., 2005; Zarasvandi et al., 2015. In the Dalli porphyry deposit, four hydrothermal alteration zones, includingpotassic, sericitic, propylitic, and argillic types have been described in the two discrete mineralized areas, namely, northern and southern stocks. Hypogenemineralization includes chalcopyrite, pyrite, and magnetite, with minor occurrences of bornite.Supergene activity has produced gossan, oxidized minerals and enrichment zones. The supergene enrichment zone contains chalcocite and covellite with a 10-20 m thickness. Mineralization in the northern stock is mainly composed of pyrite and chalcopyrite. The aim of this study is the investigation and classification of hydrothermal veins and the constraining of physicochemical compositions of ore-forming fluids using systematic investigation of fluid inclusions. Materials and methods Twenty samples were collected from drill holes. Thin and polished sections were prepared from hydrothermal veins of thepotassic, sericitic and propylitic alteration zones. Samples used for fluid inclusion measurements were collected

  2. U-Pb zircon, geochemical and Sr-Nd-Hf-O isotopic constraints on age and origin of the ore-bearing intrusions from the Nurkazgan porphyry Cu-Au deposit in Kazakhstan (United States)

    Shen, Ping; Pan, Hongdi; Seitmuratova, Eleonora; Jakupova, Sholpan


    Nurkazgan, located in northeastern Kazakhstan, is a super-large porphyry Cu-Au deposit with 3.9 Mt metal copper and 229 tonnage gold. We report in situ zircon U-Pb age and Hf-O isotope data, whole rock geochemical and Sr-Nd isotopic data for the ore-bearing intrusions from the Nurkazgan deposit. The ore-bearing intrusions include the granodiorite porphyry, quartz diorite porphyry, quartz diorite, and diorite. Secondary ion mass spectrometry (SIMS) zircon U-Pb dating indicates that the granodiorite porphyry and quartz diorite porphyry emplaced at 440 ± 3 Ma and 437 ± 3 Ma, respectively. All host rocks have low initial 87Sr/86Sr ratios (0.70338-0.70439), high whole-rock εNd(t) values (+5.9 to +6.3) and very high zircon εHf(t) values (+13.4 to +16.5), young whole-rock Nd and zircon Hf model ages, and consistent and slightly high zircon O values (+5.7 to +6.7), indicating that the ore-bearing magmas derived from the mantle without old continental crust involvement and without marked sediment contamination during magma emplacement. The granodiorite porphyry and quartz diorite porphyry are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) and depleted in high-field strength elements (HFSE), Eu, Ba, Nb, Sr, P and Ti. The diorite and quartz diorite have also LILE and LREE enrichment and HFSE, Nb and Ti depletion, but have not negative Eu, Ba, Sr, and P anomalies. These features suggest that the parental magma of the granodiorite porphyry and quartz diorite porphyry originated from melting of a lithospheric mantle and experienced fractional crystallization, whereas the diorite and quartz diorite has a relatively deeper lithospheric mantle source region and has not experienced strong fractional crystallization. Based on these, together with the coeval ophiolites in the area, we propose that a subduction of the Balkhash-Junggar oceanic plate took place during the Early Silurian and the ore-bearing intrusions and associated Nurkazgan

  3. Timescales of Porphyry Cu Formation: Bajo de la Alumbrera, NW Argentina (United States)

    Buret, Y.; Von Quadt, A.; Heinrich, C. A.; Peytcheva, I.


    Using high-precision U-Pb dating we are potentially able to determine timescales of porphyry emplacement and ore formation. Previous studies have suggested timescales of porphyry Cu formation ranging from Bajo de la Alumbrera Cu-Au deposit, NW Argentina. The deposit consists of a composite stock of dacitic porphyries. The relative timing of each porphyry intrusion is established based on clear cross-cutting relationships between different porphyry intrusions, which include the pre-mineralisation P2 porphyry, pre-syn-minerlisation EP3 porphyry, and the post-mineralisation LP3 and P4 porphyries.Single zircon crystals from individual porphyry intrusions (P2, EP3, LP3, P4) in the Alumbrera deposit have been dated using CA-ID-TIMS, employing the ET2535 tracer solution for maximum precision and accuracy. All porphyries display protracted zircon crystal growth over 100-200 ka timescales. Using the youngest zircons from each of the porphyry intrusions, Cu mineralisation occurred on 10 ka timescales, similar to those proposed by recent numerical predictions [4]. Trace element and Hf isotopic analyses may reveal geochemical distinctions within the porphyry intrusions and record temporal changes in the magmatic evolution. References: [1] Cathles and Shannon (2007) EPSL 262:92-108; [2] Ballard et al. (2001) Geology 29:383-386; [3] Harris et al. (2008) Min Dep 43: 295-314; [4] Weis et al. (2012) Science 338: 1613-1616; [5] von Quadt et al. (2011) Geology 39: 731-734.

  4. Chagas disease in Andean countries

    Directory of Open Access Journals (Sweden)

    Felipe Guhl


    Full Text Available The Andean Countries' Initiative (ACI for controlling Chagas disease was officially created in 1997 within the framework of the Hipolito Unanue Agreement (UNANUE between the Ministries of Health of Colombia, Ecuador, Peru, and Venezuela. Its objective was to interrupt transmission via vector and transfusion in the region, taking into account that there are 12.5 million people at risk in the four Andean countries forming the initiative in the area and around 3 million people are infected by Trypanosoma cruzi. The progress of control activities for the vector species present in the Andean sub-region, for different reasons, has been slow and control interventions have still not been installed in all geographical areas occupied by the target species. This has been partly due to lack of knowledge about these vector populations' biological characteristics, and consequent uncertainty about which are the appropriate control measures and strategies to be implemented in the region. The main vector species present important similarities in Venezuela and Colombia and in Ecuador and Northern Peru and they can be approached in a similar way throughout the whole regions, basing approaches on and adapting them to the current strategies being developed in Venezuela during the 1960s which have been progressively adopted in the Southern Cone and Central-American region. Additional measures are needed for keeping endemic areas free from Rhodnius prolixus silvatic populations, widely spread in the Orinoco region in Colombia and Venezuela. Regarding aetiological treatment, it is worth mentioning that (with the exception of Colombia none of the other countries forming the ACI have registered medicaments available for treating infected young people. There are no suitable follow-up programmes in the sub-region or for treating cases of congenital Chagas disease. An integral and integrated programme encompassing all the aspects including transmission by transfusion which

  5. 拉萨地块北部~90Ma斑岩型矿床年代学及成矿地质背景%Geochronology and Ore-Forming Geological Background of ~90 Ma Porphyry Copper Deposit in the Lhasa Terrane, Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    王保弟; 许继峰; 刘保民; 陈建林; 王立全; 郭琳; 王冬兵; 张万平


    A number of large-very large porphyry Cu-Mo-Au deposits have been discovered in the Tibetan plateau, which has caused widespread concern in recent years. Existing research results show that the formation ages of thse ore-bearing porphyries and porphyry deposits in the Tibetan Pleteau concentrate mainly on four stages: 120~110 Ma, ~90 Ma, 54~45 Ma and 18~12 Ma, but the ore-forming geological background of porphyry deposits forming at the second stage (90Ma) is still controversial. This study reports the zircon LA-ICPMS U-Pb and molybdenites Re-Os ages of the porphyry Cu-Mo-Au deposits in the northern Lhasa terrane, along with analysis of ore-forming background. Two weighted average 206Pb/238U ages for two granodioritic porphyry samples are 92. 1±1. 2 Ma and 93. 8±1.2 Ma, which probably record the age of magma crystallization, while the molybdenites Re-Os isotopic age of 88. 2~89. 6 Ma probably represents the age of mineralization of the Balazha porphyry deposits. Based on the regional geochemical data, this study suggests that the magmatism and mineralizaion at~90 Ma in the northern Lhasa terrane was neither the prodcut of subduction of the Neo-Tethys ocean and oceanic ridge, which are represented by the Yarlung-zangbo suture, nor the direct result of subduction of the BangongcoNujiang Ocean, but likely the product of collision process after the subduction and closure of the BangongcoNujiang Ocean.%近年来青藏高原多个大型—超大型斑岩Cu-Mo-Au矿床的发现已引起人们广泛的关注,现有研究显示这些含矿斑岩和斑岩型矿床的形成年龄主要集中在120~110 Ma、~90 Ma、54~45 Ma和18~12 Ma4个阶段,其中90 Ma左右的斑岩型矿床的成矿地质背景仍存在很大争议.本文报道拉萨地块北部尼玛县拔拉扎斑岩型矿床含矿斑岩的LA-ICPMS锆石U-Pb定年以及辉钼矿Re-OS定年结果,并分析了该期的成矿地质背景.两件花岗闪长斑岩锆石206 Pb/238U

  6. Methane origin and oxygen-fugacity evolution of the Baogutu reduced porphyry Cu deposit in the West Junggar terrain, China (United States)

    Shen, Ping; Pan, HongDi


    Most porphyry copper deposits worldwide contain magnetite, hematite, and anhydrite in equilibrium with hypogene copper-iron sulfides (chalcopyrite, bornite) and have fluid inclusions with CO2 >> CH4 that are indicative of high fO2. In contrast, the Baogutu porphyry Cu deposit in the West Junggar terrain (Xinjiang, China) lacks hematite and anhydrite, contains abundant pyrrhotite and ilmenite in equilibrium with copper-iron sulfides (chalcopyrite), and has fluid inclusions with CH4 >> CO2 that are indicative of low fO2. The mineralized intrusive phases at Baogutu include the main-stage diorite stock and minor late-stage diorite porphyry dikes. The main-stage stock underwent fractional crystallization and country-rock assimilation-contamination, and consists of dominant diorite and minor gabbro and tonalite porphyry. The country rocks contain organic carbons (0.21-0.79 wt.%). The δ13CvPDB values of the whole rocks (-23.1 to -25.8 ‰) in the wall rocks suggest a sedimentary organic carbon source. The δ13CvPDB values of CH4 (-28.2 to -36.0 ‰) and CO2 (-6.8 to -20.0 ‰) in fluid inclusions require an organic source of external carbon and equilibration of their Δ13CCO2-CH4 values (8.2-25.0 ‰) at elevated temperatures (294-830 °C) suggesting a significant contribution of thermogenic CH4. Mineral composition data on the main-stage intrusions, such as clinopyroxene, hornblende, biotite, magnetite, ilmenite, sphene, apatite, and pyrrhotite, suggest that the primary magma at Baogutu was oxidized and became reduced after emplacement by contamination with country rocks. Mineral compositions and fluid inclusion gas compositions suggest that the redox state of the system evolved from log fO2 > FMQ + 1 in the magma stage, to log fO2 country rocks assimilation-contamination, to log fO2 > FMQ in the hydrothermal stage. Though oxidized magma was emplaced initially, assimilation-contamination of carbonaceous country rocks decreased its fO2 such that exsolved fluids contained

  7. 加权Logistic回归模型在斑岩铜矿预测中的应用——以中—哈边境扎尔—玛萨吾尔成矿带为例%The Application of Weighted Logistic Regression Model in Prediction of Porphyry Copper Deposit——take Zharma-Sawur metallogenic belt, China-Kazakhstan border area, as an example

    Institute of Scientific and Technical Information of China (English)

    努丽曼古·阿不都克力木; 张晓帆; 陈川; 徐仕琪; 赵同阳


    加权Logistic回归是基于GIS成矿预测的主要方法之一,其模型是不同于线性模型的一种类型.它具有强大的空间分析功能、适用性强、不受任何独立条件的约束、预测结果更可靠,因此在矿产资源评价研究中得到了很多地质学家的青睐.以矿床模型和成矿理论为基础,加权Logistic回归分析模型在成矿预测中的应用主要包括三部分:加权Logistic回归模型的建立及其应用、成矿有利度综合评价、成矿远景区圈定.本文以中国—哈萨克斯坦边境地区扎尔玛—萨吾尔成矿带斑岩型铜矿为例,探讨了基于GIS的加权Logistic回归模型在成矿预测中的应用.%Weighted Logistic Regression is one of the main methods of mineral potential mapping. It is different from linear model. Because of its powerful spatial analysis function, strong adaptability, unconstrained by independent conditions, and more reliable prediction results, Weighted Logistic Regression is widely used by many geologists in mineral resources assessment. Based on the mineral deposit model and theory, Weighted Logistic Regression is consists of three parts: (1) Establishment of weighted logistic regression model for mineral potential mapping; (2 ) comprehensive evaluation of favorable degrees; (3 ) mineral potential mapping of study area. By the Weighted Logistic Regression model for mineral potential mapping, Zharma-Sawur Metallogic Belt which across border region of China and Kazakhstan is studied and mineral prospecting area of porphyry copper deposit is mapped. At the end, the availability of Weighted Logistic Regression Model for mineral potential mapping is discussed.

  8. Administrative Law in the Andean Community of Nations


    Santos Rodríguez, Jorge Enrique


    One of the contemporary tendencies of Administrative Law is the recognition of its existence beyond the borders of a State. Under such premise, this paper aims to demonstrate that in the Andean Community of Nations sufficient elements to consider the existence of an Andean administrative Law. In the Andean statutes and rules, it is possible to identify an administrative function, as well as an administrative organization inside the Andean Integration System; and a system of Andean administrat...

  9. Andean settlers rush for Amazonia. (United States)

    Serra-vega, J


    Governments of Andean countries (Peru, Bolivia, Colombia, Ecuador, and Venezuela) have encouraged migration to the Amazon Basin, which has contributed to its destruction. Population pressure, landlessness, and poverty are the inducements to migrate. Efforts to populate the Amazon forest were begun as early as 1964 in Peru without international notice. By 1980, logging was allowed in Peru, and Brazil considered colonization of the Amazon essential to national sovereignty. By 1986, outside of Lima, Peru, a development project originally funded by the World Bank, the InterAmerican Development Bank, and the US, resulted in conflicts between settlers and Indians, in loggers indiscriminately cutting, and in farmers using slash and burn techniques to clear forests. Elsewhere the Peruvian Amazon, in San Ignacio, the population was growing by 5.5%/year. The jungle road that had been started but never completed, Carretera Marginal, destroyed 5 million hectares of primary forest, and much of the 600,000 hectares of arable land gained by the road suffered from inappropriate farming practices which caused massive erosion and laterization of the soils. Food crop production declined, and production of coca for cocaine increased. Coca crops are controlled by the Shining Path guerrillas, who are trying to overthrow the Peruvian government. Devastation of Ecuador around Lago Agrio continues. In Colombia, east of Bogota, forests have disappeared and hills have eroded and silted up rivers and dams. The Andean piedmont in Bolivia has also been devastated by loggers and by slash and burn farming. Southeastern Bolivian forests have been cleared for soya bean cultivation on poor soils. Social and economic crises propel people into the remaining forests. The solution is to ease foreign debt, transfer appropriate technology at affordable prices, refuse to finance destructive development, and help to educate and train scientific researchers. Family planning services are also urgently needed

  10. Relations between A-type granites and copper mineralization as exemplified by the Machangqing Cu deposit

    Institute of Scientific and Technical Information of China (English)


    This paper deals with the relations between the Machangqing rockbody which corresponds to the A-type granites and porphyry copper mineralization in terms of petrochemistry,trace element geochemistry,fluid inclusion geochemistry and isotope geochemistry.The results show that the Machangqing porphyry copper deposit was formed from the fluid predominated by magmatic fluid.This kind of ore-forming fluid was just differentiated from the magma responsible for the A-type granites.Therefore,as viewed from whether they contain water or not,the A-type granites can,at least,be divided into two types:water-bearing and water-free.The water-bearing A-type granites can serve as the host of porphyry copper deposits under certain geological conditions.

  11. Relations between A-type granites and copper mineralization as exemplified by the Machangqing Cu deposit

    Institute of Scientific and Technical Information of China (English)

    毕献武; 胡瑞忠; 叶造军; 邵树勋


    This paper deals with the relations between the Machangqing rockbody which corresponds to the A-type granites and porphyry copper mineralization in terms of petrochemistry, trace element geochemistry, fluid inclusion geochemistry and isotope geochemistry. The results show that the Machangqing porphyry copper deposit was formed from the fluid predominated by mag-matic fluid. This kind of ore-forming fluid was just differentiated from the magma responsible for the A-type granites. Therefore, as viewed from whether they contain water or not, the A-type granites can, at least, be divided into two types: water-bearing and water-free. The water-bearing A-type granites can serve as the host of porphyry copper deposits under certain geological conditions.

  12. Phylogenetic insights into Andean plant diversification

    Directory of Open Access Journals (Sweden)

    Federico eLuebert


    Full Text Available Andean orogeny is considered as one of the most important events for the developmentof current plant diversity in South America. We compare available phylogenetic studies anddivergence time estimates for plant lineages that may have diversified in response to Andeanorogeny. The influence of the Andes on plant diversification is separated into four major groups:The Andes as source of new high-elevation habitats, as a vicariant barrier, as a North-Southcorridor and as generator of new environmental conditions outside the Andes. Biogeographicalrelationships between the Andes and other regions are also considered. Divergence timeestimates indicate that high-elevation lineages originated and diversified during or after the majorphases of Andean uplift (Mid-Miocene to Pliocene, although there are some exceptions. Asexpected, Andean mid-elevation lineages tend to be older than high-elevation groups. Mostclades with disjunct distribution on both sides of the Andes diverged during Andean uplift.Inner-Andean clades also tend to have divergence time during or after Andean uplift. This isinterpreted as evidence of vicariance. Dispersal along the Andes has been shown to occur ineither direction, mostly dated after the Andean uplift. Divergence time estimates of plant groupsoutside the Andes encompass a wider range of ages, indicating that the Andes may not benecessarily the cause of these diversifications. The Andes are biogeographically related to allneighbouring areas, especially Central America, with floristic interchanges in both directionssince Early Miocene times. Direct biogeographical relationships between the Andes and otherdisjunct regions have also been shown in phylogenetic studies, especially with the easternBrazilian highlands and North America. The history of the Andean flora is complex and plantdiversification has been driven by a variety of processes, including environmental change,adaptation, and biotic interactions

  13. Geochemical, microtextural and petrological studies of the Samba prospect in the Zambian Copperbelt basement: a metamorphosed Palaeoproterozoic porphyry Cu deposit. (United States)

    Master, Sharad; Mirrander Ndhlovu, N.


    Ever since Wakefield (1978, IMM Trans., B87, 43-52) described a porphyry-type meta-morphosed Cu prospect, the ca 50 Mt, 0.5% Cu Samba deposit (12.717°S, 27.833°E), hosted by porphyry-associated quartz-sericite-biotite schists in northern Zambia, there has been controversy about its origin and significance. This is because it is situated in the basement to the world's largest stratabound sediment-hosted copper province, the Central African Copperbelt, which is hosted by rocks of the Neoproterozoic Katanga Supergroup. Mineralization in the pre-Katangan basement has long played a prominent role in ore genetic models, with some authors suggesting that basement Cu mineralization may have been recycled into the Katangan basin through erosion and redeposition, while others have suggested that the circulation of fluids through Cu-rich basement may have leached out the metals which are found concentrated in the Katangan orebodies. On the basis of ca 490-460 Ma Ar-Ar ages, Hitzman et al. (2012, Sillitoe Vol., SEG Spec. Publ., 16, 487-514) suggested that Samba represents late-stage impregnation of copper mineralization into the basement, and that it was one of the youngest copper deposits known in the Central African Copperbelt. If the Samba deposit really is that young, then it would have post-dated regional deformation and metamorphism (560-510 Ma), and it ought to be undeformed and unmetamorphosed. The Samba mineralization consists of chalcopyrite and bornite, occurring as disseminations, stringers and veinlets, found in a zone >1 km along strike, in steeply-dipping lenses up to 10m thick and >150m deep. Our new major and trace element XRF geochemical data (14 samples) show that the host rocks are mainly calc-alkaline metadacites. Cu is correlated with Ag (Cu/Ag ~10,000:1) with no Au or Mo. Our study focused on the microtextures and petrology of the Samba ores. We confirm that there is alteration of similar style to that accompanying classical porphyry Cu mineralization

  14. Two new Cystoderma species from high Andean Ecuador

    DEFF Research Database (Denmark)

    Saar, I.; Læssøe, Thomas


    ABSTRACT: Two new agaric species, Cystoderma andinum and C. papallactae are described from high Andean Ecuador.......ABSTRACT: Two new agaric species, Cystoderma andinum and C. papallactae are described from high Andean Ecuador....

  15. Geochemical element mobility during the hydrothermal alteration in the Tepeoba porphyry Cu-Mo-Au deposits at Balikesir, NW Turkey (United States)

    Abdelnasser, Amr; Kiran Yildirim, Demet; Doner, Zeynep; Kumral, Mustafa


    The Tepeoba porphyry Cu-Mo-Au deposit represents one of the important copper source and mineral deposits in the Anatolian tectonic belt at Balikesir province, NW Turkey. It considered as a vein-type deposit locally associated with intense hydrothermal alteration within the brecciation, quartz stockwork veining, and brittle fracture zones in the main host rock that represented by hornfels, as well as generally related to the shallow intermediate to silicic intrusive Eybek pluton. Based on the field and geologic relationships and types of ore mineral assemblages and the accompanied alteration types, there are two mineralization zones; hypogene (primary) and oxidation/supergene zones are observed associated with three alteration zones; potassic, phyllic, and propylitic zones related to this porphyry deposit. The phyllic and propylitic alterations locally surrounded the potassic alteration. The ore minerals related to the hypogene zone represented by mostly chalcopyrite, Molybdenite, and pyrite with subordinate amount of marcasite, enargite, and gold. On the other hand they include mainly cuprite with chalcopyrite, pyrite and gold as well as hematite and goethite at the oxidation/supergene zone. This study deals with the quantitative calculations of the mass/volume changes (gains and losses) of the major and trace elements during the different episodes of alteration in this porphyry deposit. These mass balance data reveal that the potassic alteration zone that the main Cu- and Mo-enriched zone, has enrichment of K, Si, Fe, and Mg, and depletion of Na referring to replacement of plagioclase and amphibole by K-feldspar, sericite and biotite. While the propylitic alteration that is the main Mo- and Au-enriched zone is accompanied with K and Na depletion with enrichment of Si, Fe, Mg, and Ca forming chlorite, epidote, carbonate and pyrite. On the other hand the phyllic alteration that occurred in the outer part around the potassic alteration, characterized by less amount

  16. Microgranular enclaves in island-arc andesites: A possible link between known epithermal Au and potential porphyry Cu-Au deposits in the Tulasu ore cluster, western Tianshan, Xinjiang, China (United States)

    Zhao, Xiaobo; Xue, Chunji; Symons, David T. A.; Zhang, Zhaochong; Wang, Honggang


    The successful exploration for porphyry copper deposit in western Tianshan, Xinjiang, faces great challenge. Tulasu basin is an important epithermal gold ore cluster in western Tianshan, which was formed in a southwest-Pacific-type island-arc setting during the late Paleozoic by the southward subduction of the North Tianshan ocean beneath the Yili plate. Porphyry Cu-Au deposits are possibly to be found at depth or adjacent to these epithermal gold deposits. Some sulfide-mineralized microgranular enclaves of monzonite porphyry and microdiorite were found in andesites of the Tawuerbieke gold district, Tulasu basin. The enclaves are randomly distributed, with generally round or subangular shape and commonly clearly defined within their host andesite, and have a chilled surrounding margin of andesite. The monzonite porphyry enclaves (MPE) exhibit porphyritic texture with the phenocrysts of plagioclase and K-feldspar. The microdiorite enclaves (MDE) are mainly composed of plagioclase and hornblende with an aplitic texture and massive structure. The host andesites show porphyritic texture, with the phenocrysts major of plagioclase, minor of hornblende and clinopyroxene. The groundmass consists of short-column plagioclase and minor clinopyroxene with a hyalopilitic texture. Zircon grains from a MPE sample yield a weighted 206Pb/238U age of 356.2 ± 4.3 Ma (n = 13, MSWD = 1.11), which is effectively coincident with the 360.5 ± 3.4 Ma (n = 20, MSWD = 0.61) of an andesite sample within analytical error, indicating that they were coeval. In addition, the MPE, MDE and the andesite samples share similar normalized incompatible element and rare earth element patterns that are characterized by a pronounced enrichment of large ion lithophile elements and a deficit of high field strength elements. Moreover, the samples show similar Nd isotope compositions to the contemporary andesites and basaltic andesites. Detailed petrology, geochronology and geochemistry studies suggest that

  17. Xinjiang to Build Its Largest Copper Mine

    Institute of Scientific and Technical Information of China (English)


    <正>On September 16, the 6,000,000-ton mining project of Hudehe Copper Mine kicked off, which is the largest copper mine in Xinjiang.Jointly developed by Xinjiang Nonferrous Metals Group and Gansu Jianxin Group, Hudehe Copper Mine is located at Tuoli County, Tacheng Prefecture, Xinjiang. It is a large-scale porphyry-type copper deposit with proven copper reserve of 362,500 tons and prospective reserve of 1,000,000 tons(metal content). According to the preliminary plan, it will be built into a mine with mining and dressing capacity of 6,000,000 tons/year. With a total investment of RMB 1.466 billion, the project is expected to achieve annual sales revenue of RMB 0.8 billion and provide jobs for nearly 1,000 people.

  18. Administrative Law in the Andean Community of Nations

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Santos Rodríguez


    Full Text Available One of the contemporary tendencies of Administrative Law is the recognition of its existence beyond the borders of a State. Under such premise, this paper aims to demonstrate that in the Andean Community of Nations sufficient elements to consider the existence of an Andean administrative Law. In the Andean statutes and rules, it is possible to identify an administrative function, as well as an administrative organization inside the Andean Integration System; and a system of Andean administrative rules and an administrative justice system.

  19. Evolving Regional Security in the Andean Region (United States)


    security forces or judicial systems reduces the effectiveness of regional cooperation. Past efforts to achieve consensus among the Andean states have...Trimestre 2001. Nuñez, Joseph. Una Arquitectura para la Seguridad del Siglo XXI par alas Américas: Cooperación Multilateral, Paz y Poder Flexible

  20. Andean region: measles on the way out. (United States)


    In August 1996, health officials, program managers, epidemiologists, laboratory representatives, UNICEF, Rotary International, and Pan American Health Organization staff attended the VII Andean EPI Meeting in Quito, Ecuador, to review the progress of the Expanded Program on Immunization (EPI). All Andean countries have conducted catch-up measles vaccination campaigns targeting children 9 months to 15 years old. These campaigns achieved 90% vaccine coverage and a strong reduction in measles incidence (only 7 confirmed cases in 1996). Follow-up campaigns were conducted during 1995-1996 in Colombia, Peru, and Chile. They were expected in Bolivia, Ecuador, Peru, and Venezuela during 1997-1999. The Andean countries implemented a national surveillance system for measles in 1995. Meeting representatives made eight recommendations regarding measles. For example, health officials should reach and maintain routine vaccination coverage greater than 95% for children 12-23 months old in each municipality. Laboratory representatives proposed recommendations on uniform criteria for measles diagnosis. The last indigenous wild poliovirus in the Americas was isolated in 1991. Imported wild poliovirus remains a concern. The Andean countries are expanding surveillance of neonatal tetanus activities. Since 1989 the frequency of neonatal tetanus has been falling in the Andean region, especially in Bolivia and Peru. The impact of migration on the control of neonatal tetanus should be a higher priority. Participants repeated the need for systematic use and continuous monitoring of EPI indicators (e.g., vaccination coverage). Three countries plan on analyzing surveys on missed opportunities for vaccination in 1996. Three countries presented progress reports on hepatitis B vaccination and surveillance. Participants issued recommendations on quality control of vaccines. The responsibility for quality control lies with the manufacturers and the government. Vaccines for invasive diseases (e

  1. Volcanism and associated hazards: the Andean perspective (United States)

    Tilling, R. I.


    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  2. Volcanism and associated hazards: The Andean perspective (United States)

    Tilling, R.I.


    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  3. Volcanism and associated hazards: the Andean perspective

    Directory of Open Access Journals (Sweden)

    R. I. Tilling


    Full Text Available Andean volcanism occurs within the Andean Volcanic Arc (AVA, which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions" recognized worldwide that have occurred from the Ordovician to the Pleistocene.

    The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru. The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (<0.05 km3 in 1985 of Nevado del Ruiz (Colombia killed about 25 000 people – the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent

  4. Mineralization and Geochemical Exploration in Volcanic- Plotonic Area of Halakabad Village (Sabzevar, Regarding to Cu-Porphyry Deposits

    Directory of Open Access Journals (Sweden)

    Panahi Shahri, M.


    Full Text Available The investigated area is located 30 Km south of Sabzevar in Halakabad village. Geological phenomenons in area follow a trend of NW-SE. Mineralization consists of metallic and non-metallic (kaolin mineralization. Disseminated and veinlet mineralization is generally associated with argillic alteration type. Pyrite is the most widespread type of sulfide mineralization in Halakabad occurrences. It usually displays a euhedral habit and have occurred at least in two generations. Calcopyrite is common in veinlets although in minor amounts. Secondary sulfuric acid weathering of the ore has generated huge surficial amounts of oxide and sulfate minerals which of hematite and jarosite are the most abundant. Geochemical exploration was conducted over both drainage geochemistry and rock geochemistry. Results show that some of the stream sediments have higher concentrations of Copper and Zinc than normal. This anomalies maches with monzonite outcrops in area. The chip rock geochemical data shows highest values in west of halakabad mine for Cu and Zn respectively 500 and 900 ppm. These data represents that all samples collected from surficial areas of east of area contain lower concentrations of Copper while sulfide mineralization is more than the other parts. Presence of favorable alteration system in region, presence of monzonite subvolcanic intrusions and regional geological criteria indicates a possible Cu-Au porphyry system in Halakabad area.

  5. Using the concentration-volume (C-V) fractal model in the delineation of gold mineralized zones within the Tepeoba porphyry Cu-Mo-Au, Balikesir, NW Turkey (United States)

    Kumral, Mustafa; Abdelnasser, Amr; Karaman, Muhittin; Budakoglu, Murat


    The Tepeoba porphyry Cu-Mo-Au mineralization that located at the Biga peninsula (W Turkey) developed around the Eybek pluton concentrated at its southern contact. This mineralization that hosted in the hornfels rocks of Karakaya Complex is associated with three main alteration zones; potassic, phyllic and propylitic alterations along the fault controlled margins of the Eybek pluton and quartz stockwork veining as well as brecciation zones. As well as two mineralized zones were occurred in the mine area; hypogene and oxidation/supergene zone. The hypogene zone has differentiated alteration types; high potassic and low phyllic alteration, while the oxidation/supergene zone has high phyllic and propylitic alterations. This work deals with the delineation of gold mineralized zone within this porphyry deposit using the concentration-volume (C-V) fractal model. Five zones of gold were calculated using its power-law C-V relationship that revealed that the main phase of gold mineralization stated at 5.3083 ppm Au concentration. In addition, the C-V log-log plot shows that the highly and moderately Au mineralization zone developed in western part of deposit correlated with oxidation zone related to propylitic alteration. On the other hand, its weakly mineralization zone has a widespread in the hypogene zone related to potassic alteration. This refers to the enrichment of gold and depletion of copper at the oxidation/supergene zone is due to the oxidation/supergene alteration processes that enrich the deposits by the meteoric water. Keywords: Concentration-volume (C-V) fractal model; gold mineralized zone; Tepeoba porphyry Cu-Mo-Au; Balikesir; NW Turkey.

  6. Where and When did High Andean Relief Emerge?: Insights From Molecular Phylogenies of Andean Biota (United States)

    Sempere, T.; Picard, D.; Plantard, O.


    Emergence of mountains along the Andean margin created new ecosystems and thus triggered a variety of adaptive biotic radiations, to the point that the Andes are to-day one of the world's major biodiversity hotspots. The rising Andes came to serve as a rain barrier: cloud forests developed along their eastern side due to orographic concentration of the westward-moving Amazonian moisture, and environments became drier in the west, with highland steppes extending above ~2-3 km. Relevant biologic data concerning Andean taxa adapted to these environments might therefore shed some light on the issue of Andean orogeny and surface uplift. Phylogeography (the analysis of phylogenetic trees in terms of biogeographic distributions) and phylochronology (the use of phylogenetic trees as molecular clocks) can be employed to reconstruct syn- orogenic radiations and estimate their timing, respectively. We use published molecular phylogenies that inform on the evolution of a variety of Andean animal and plant taxa, and therefore provide indirect means to assess and approximately date the acquisition of altitude. Phylogeographic analyses of 6 phylogenetic trees concerning unrelated Andean biota coincide in having their basal clades established in areas within the Central Andean Orocline (CAO), 5 of them clearly pointing to southern Peru and/or western Bolivia as the region of origin of the corresponding high-Andean taxa. A histogram of 9 phylochronologic estimates, based on trees concerning unrelated taxa (independently constructed and calibrated), suggests that the 2.0-2.5 km critical altitude was acquired during the 23-17 Ma or 26-16 Ma intervals (depending on the threshold used), confirming some geomorphic and geologic estimates (but conflicting with others). Although more data are needed, these results suggest that it was within the CAO and approximately during the early Miocene that the Andes acquired altitudes sufficient to trigger radiations of cold-adapted taxa, i.e. >~2 km

  7. Geology and reconnaissance stable isotope study of the Oyu Tolgoi porphyry Cu-Au system, South Gobi, Mongolia (United States)

    Khashgerel, B.-E.; Rye, R.O.; Hedenquist, J.W.; Kavalieris, I.


    The Oyu Tolgoi porphyry Cu-Au system in the South Gobi desert, Mongolia, comprises five deposits that extend over 6 km in a north-northeast-oriented zone. They occur in a middle to late Paleozoic are terrane and are related to Late Devonian quartz monzodiorite intrusions. The Hugo Dummett deposits are the northernmost and deepest, with up to 1,000 m of premineral sedimentary and volcanic cover rock remaining. They are the largest deposits discovered to date and characterized by high-grade copper (>2.5% Cu) and gold (0.5-2 g/t) mineralization associated with intense quartz veining and several phases of quartz monzodiorite intruded into basaltic volcanic host rocks. Sulfide minerals in these deposits are zoned outward from a bornite-dominated core to chalcopyrite, upward to pyrite ?? enargite and covellite at shallower depth. The latter high-sulfidation-state sulfides are hosted by advanced argillic alteration mineral associations. This alteration is restricted mainly to dacitic ash-flow tuff that overlies the basaltic volcanic rock and includes ubiquitous quartz and pyrophyllite, kaolinite, plus late dickite veins, as well as K alunite, Al phosphate-sulfate minerals, zunyite, diaspore, topaz, corundum, and andalusite. A reconnaissance oxygen-hydrogen and sulfur isotope study was undertaken to investigate the origin of several characteristic alteration minerals in the Oyu Tolgoi system, with particular emphasis on the Hugo Dummett deposits. Based on the isotopic composition of O, H, and S (??18O(SO4) = 8.8-20.1???, ??D = -73 to -43???, ??34S = 9.8-17.9???), the alunite formed from condensation of magmatic vapor that ascended to the upper parts of the porphyry hydrothermal system, without involvement of significant amounts of meteoric water. The isotopic data indicate that pyrophyllite (??18O = 6.5-10.9???, ??D = -90 to -106???) formed from a magmatic fluid with a component of meteoric water. Muscovite associated with quartz monzodiorite intrusions occurs in the core

  8. Time scales of porphyry Cu deposit formation: insights from titanium diffusion in quartz (United States)

    Mercer, Celestine N.; Reed, Mark H.; Mercer, Cameron M.


    Porphyry dikes and hydrothermal veins from the porphyry Cu-Mo deposit at Butte, Montana, contain multiple generations of quartz that are distinct in scanning electron microscope-cathodoluminescence (SEM-CL) images and in Ti concentrations. A comparison of microprobe trace element profiles and maps to SEM-CL images shows that the concentration of Ti in quartz correlates positively with CL brightness but Al, K, and Fe do not. After calibrating CL brightness in relation to Ti concentration, we use the brightness gradient between different quartz generations as a proxy for Ti gradients that we model to determine time scales of quartz formation and cooling. Model results indicate that time scales of porphyry magma residence are ~1,000s of years and time scales from porphyry quartz phenocryst rim formation to porphyry dike injection and cooling are ~10s of years. Time scales for the formation and cooling of various generations of hydrothermal vein quartz range from 10s to 10,000s of years. These time scales are considerably shorter than the ~0.6 m.y. overall time frame for each porphyry-style mineralization pulse determined from isotopic studies at Butte, Montana. Simple heat conduction models provide a temporal reference point to compare chemical diffusion time scales, and we find that they support short dike and vein formation time scales. We interpret these relatively short time scales to indicate that the Butte porphyry deposit formed by short-lived episodes of hydrofracturing, dike injection, and vein formation, each with discrete thermal pulses, which repeated over the ~3 m.y. generation of the deposit.

  9. The Andean Geotrail (2): An educational project (United States)

    Galland, O.; Sassier, C.; Vial, M.; Thiberge, P.


    The role of Geosciences in our society is of primary importance. Its implications for humanity relate to major challenges such as climate change, managing energy resources, natural hazard mitigation, and water scarcity. Despite these issues being familiar to specialists, this is in general not the case for the public. In a world, where the impact of human activity is beginning to be seen on the environment, knowledge of the Earth and its history is paramount to make informed decisions that will influence our future. The necessity to educate the global population and raise awareness of Geosciences has led UNESCO to designate 2009 the International Year of the Planet Earth. In the framework of the UNESCO International Year of Planet Earth, we performed an educational project in collaboration with primary, secondary and high schools in France and Norway. Geosciences are not usually studied in schools, but this project allowed more than 600 pupils (from 17 schools) aged 8 to 18 years old to share the geological discoveries of our popular science adventure The Andean Geotrail (see Sassier et al., this session). The main educational goal was to promote Geosciences by illustrating in the field what geology is. Our natural laboratory was the spectacular Andean Cordillera. The secondary goal was to promote careers in geology and highlight their variety by allowing the pupils to meet geologists through portraits of geologists. The teachers of the partner schools used our project as a dynamic complement to their theoretical lessons. To set up this partnership, we obtained the support of the pedagogic supervisors of the French Ministry of National Education. The pedagogical project consisted of three steps: (1) Before the expedition (Oct.-Nov. 2008), we visited the pupils of each partner school to present the project, establish personal contact and engage the pupils in our adventure. (2) During The Andean Geotrail itself (Nov. 2008-Aug. 2009), we continuously documented our

  10. Tectonomagmatic Associations on the Central Andean Plateau (United States)

    de Silva, S. L.; Viramonte, J. G.


    The Neogene evolution of the Central Andes is characterized by a strong association between plate convergence, mountain building and plateau formation, and magmatism. Plateau uplift by crustal shortening and thickening in the lower crust is broadly coincident with large scale silicic magmatism defined by the Neogene Central Andean ignimbrite province. Of particular interest here are the spatiotemporal correlations between silicic magmatism and tectonic evolution of the Altiplano-Puna plateau. Although magmatism is driven by the subduction-related flux from mantle to crust, the shift to "crustal" magmatism as indicated by elevated crustal isotopic indices after ~10Ma suggests a link between crustal thickening, plateau formation and silicic magmatism. In particular, elevated geotherms associated with crustal thickening and enhanced mantle flux associated with lithospheric delamination may have played a role in thermally preparing the Central Andean crust for enhanced silicic magma production during the extensive Neogene ignimbrite flare-up. Emplacement of these magmas in the upper crust throughout the Neogene may have fuelled a period of significant interaction between magmatism and tectonism on the plateau. With particular reference to the 21° to 24°S segment of the Central Andes, spatial and structural coincidence of calderas of the Altiplano Puna Volcanic Complex with the NW-SE striking Calama-Olacapata-El Toro fault zone suggests significant tectonomagmatic interaction. Location of calderas suggest that these regional faults focused magma intrusion and storage, while spatially and temporally correlated eruption pulses connote a tectonic control. Indeed, current thermomechanical models of magma chamber development and eruption triggering promote a role for external triggering of "perched" upper crustal magma chambers. This might have been achieved by melt-enhanced deformation, or alternatively, significant uplift (~1km) associated with the development of large

  11. Geochemical Data for Samples Collected in 2008 Near the Concealed Pebble Porphyry Cu-Au-Mo Deposit, Southwest Alaska (United States)

    Fey, David L.; Granitto, Matthew; Giles, Stuart A.; Smith, Steven M.; Eppinger, Robert G.; Kelley, Karen D.


    In the summer of 2007, the U.S. Geological Survey (USGS) began an exploration geochemical research study over the Pebble porphyry copper-gold-molybdenum deposit. This report presents the analytical data collected in 2008. The Pebble deposit is world class in size, and is almost entirely concealed by tundra, glacial deposits, and post-Cretaceous volcanic rocks. The Pebble deposit was chosen for this study because it is concealed by surficial cover rocks, is relatively undisturbed (except for exploration company drill holes), is a large mineral system, and is fairly well-constrained at depth by the drill hole geology and geochemistry. The goals of this study are to 1) determine whether the concealed deposit can be detected with surface samples, 2) better understand the processes of metal migration from the deposit to the surface, and 3) test and develop methods for assessing mineral resources in similar concealed terrains. The analytical data are presented as an integrated Microsoft Access 2003 database and as separate Excel files.

  12. The new Andean Regional Office of Astronomy for Development (ROAD) (United States)

    Char, Farid; Forero-Romero, Jaime


    The Andean Regional Office of Astronomy for Development (ROAD) is a new effort in South America to serve several goals in astronomical development. Six countries (Bolivia, Colombia, Chile, Ecuador, Perú and Venezuela) will work together, representing a common language block in the Andean region and focusing on develop strategies to strengthen the professional research, education and popularization of astronomy. Our current Working Structure comprises a ROAD Coordinator and Coordinators per Task Force, as well as Organizing Committees, Collaborators and Volunteers.The participating institutions of this new ROAD have been involved in many projects involving each of the current OAD’s Task Forces: research, schools and children and public, exploring educational activities/material to be shared among the Andean countries, standardizing the knowledge and creating inspirational experiences. We expect to generate many efforts in order to bring a more homogeneous activity in each Andean country, taking into account the special role of Chile in global astronomy, due to its great conditions for astronomy and the involvement of many professional observatories, universities and astronomy institutions.Our current (and upcoming) most relevant activities includes: Andean Schools on Astronomy, Andean Graduate Program and Massive Open Online Courses (TF1); Virtual Training Sessions and Teaching material for the visually impaired students; Annual TF2 meeting to gather all the collaborators (TF2); Development for planetariums and Communicating Astronomy with the Public (TF3). The Andean region, in the other hand, will also be involved in at least two important events: the CAP Meeting in May 2016 and the XV LARIM in October 2016 (both in Colombia); and Chile will bid to host the XXXI IAU GA in 2021, with the aim of show the great advances in astronomical development from the Andean region and South America.

  13. Late Cretaceous porphyry Cu and epithermal Cu-Au association in the Southern Panagyurishte District, Bulgaria: the paired Vlaykov Vruh and Elshitsa deposits (United States)

    Kouzmanov, Kalin; Moritz, Robert; von Quadt, Albrecht; Chiaradia, Massimo; Peytcheva, Irena; Fontignie, Denis; Ramboz, Claire; Bogdanov, Kamen


    Vlaykov Vruh-Elshitsa represents the best example of paired porphyry Cu and epithermal Cu-Au deposits within the Late Cretaceous Apuseni-Banat-Timok-Srednogorie magmatic and metallogenic belt of Eastern Europe. The two deposits are part of the NW trending Panagyurishte magmato-tectonic corridor of central Bulgaria. The deposits were formed along the SW flank of the Elshitsa volcano-intrusive complex and are spatially associated with N110-120-trending hypabyssal and subvolcanic bodies of granodioritic composition. At Elshitsa, more than ten lenticular to columnar massive ore bodies are discordant with respect to the host rock and are structurally controlled. A particular feature of the mineralization is the overprinting of an early stage high-sulfidation mineral assemblage (pyrite ± enargite ± covellite ± goldfieldite) by an intermediate-sulfidation paragenesis with a characteristic Cu-Bi-Te-Pb-Zn signature forming the main economic parts of the ore bodies. The two stages of mineralization produced two compositionally different types of ores—massive pyrite and copper-pyrite bodies. Vlaykov Vruh shares features with typical porphyry Cu systems. Their common geological and structural setting, ore-forming processes, and paragenesis, as well as the observed alteration and geochemical lateral and vertical zonation, allow us to interpret the Elshitsa and Vlaykov Vruh deposits as the deep part of a high-sulfidation epithermal system and its spatially and genetically related porphyry Cu counterpart, respectively. The magmatic-hydrothermal system at Vlaykov Vruh-Elshitsa produced much smaller deposits than similar complexes in the northern part of the Panagyurishte district (Chelopech, Elatsite, Assarel). Magma chemistry and isotopic signature are some of the main differences between the northern and southern parts of the district. Major and trace element geochemistry of the Elshitsa magmatic complex are indicative for the medium- to high-K calc-alkaline character of

  14. The Andean Geotrail (1): A scientific adventure (United States)

    Sassier, C.; Galland, O.; Raufaste, C.; Mair, K.


    The role of Geosciences in our society is of primary importance. Its implications for humanity relate to major challenges such as climate change, managing energy resources, natural hazard mitigation, and water scarcity. Despite these issues being familiar to specialists, this is in general not the case for the public. In a world, where the impact of human activity is beginning to be seen on the environment, knowledge of the Earth and its history is paramount to make informed decisions that will influence our future. The necessity to educate the global population and raise awareness of Geosciences has led UNESCO to designate 2009 the International Year of the Planet Earth. In this context and with the label of the UNESCO, we organized and performed a popular science adventure that was followed in real time by both school children and many adults around the world. The Andean Geotrail consisted of a cycling expedition through a spectacular geological environment, the Andean Cordillera. During the nine month expedition, we cycled 8000 km and walked 400 km from Ushuaia in the Southern tip of Argentina to Nazca in Peru to encounter a rich variety of geological environments: active volcanoes, earthquakes, mineral and hydrocarbon deposits, and fantastic geological scenery. All this makes the Andes a great pedagogical natural laboratory. During the expedition, we visited spectacular geological localities that illustrate key Earth Science phenomena (such as mines and hydrocarbon deposits, erupting volcanoes and seismogenically active areas, and national parks) and discovered their implications for the local people. Along the way, we interviewed local geologists and scientists who helped us understand the geology of their areas. We gathered our own observations with those of the local specialists and published essays, articles and photographs on our website and blog (, Seventeen schools in France and Norway

  15. Origin of the Lengshuigou porphyry-skarn Cu deposit in the Zha-Shan district, South Qinling, central China, and implications for differences between porphyry Cu and Mo deposits (United States)

    Xie, Guiqing; Mao, Jingwen; Wang, Ruiting; Meng, Deming; Sun, Jia; Dai, Junzhi; Ren, Tao; Li, Jianbi; Zhao, Haijie


    Porphyry Cu and Mo deposits are two economically important types of metal deposits worldwide, but factors controlling their difference remain enigmatic. Compared with the well-studied large porphyry Mo province in the south margin of the North China Block (S-NCB), the origin of newly discovered porphyry Cu deposits in the South Qinling (SQB) is poorly constrained. Integrated zircon LA-ICPMS U-Pb and molybdenite Re-Os ages and geological evidence indicate three stages of magmatism at Lengshuigou: (1) late Neoproterozoic (718 to 704 Ma) quartz diorite + albitite + granite association during the pre-ore stage, (2) 146 to 145 Ma granodiorite porphyry during the syn-ore stage, and (3) 145 Ma granite porphyry during the post-ore stage. Elemental and Sr-Nd isotopic evidence provide important constraints on their magma source. Pre-ore Neoproterozoic quartz diorite + albitite + granite was derived by re-melting of a mixture of crustal and juvenile mantle materials, and stronger fractional crystallization was involved in these ore-hosting intrusions than in contemporary granitoids hosted in the Douling Group. Syn-ore granodiorite porphyry was derived from mantle-derived magma with contributions from different proportions of crustal components. Post-ore granite porphyry was derived mainly from a crustal source. Nearly contemporaneous porphyry Cu and Mo systems were identified in Qinling Province, including the 147-139 Ma porphyry Mo systems in the S-NCB and 150-146 Ma porphyry Cu systems in the SQB. Granitic stocks related to porphyry Cu systems in the SQB are characterized by moderate SiO2 contents (58.01-69.07 %) and less radiogenic Nd-Hf isotopes (ɛNd(t) = -3.8 to -6.3, ɛHf(t) = -4.5 to +1.6), whereas the granitic stocks related to porphyry Mo deposits in the S-NCB have high SiO2 concentrations (64.00-76.00 %) and more radiogenic Nd-Hf isotopes (ɛNd(t) = -18.0 to -11.6, ɛHf(t) = -26.3 to -13.5). In addition, molybdenite from the Chigou and Lengshuigou porphyry Cu

  16. Imperial porphyry from Gebel Abu Dokhan, the Red Sea Mountains, Egypt

    DEFF Research Database (Denmark)

    Makovicky, Emil; Frei, Robert; Karup-Møller, Sven;


    grey to red and are characterized by abundant, weakly aligned white to pink feldspar phenocrysts. The magmatic phenocrysts – plagioclase, hornblende, pyroxene, opaque components and apatite – are always altered. The red colour of the porphyry stems from alteration of phenocrysts and groundmass which...

  17. Andean tectonics: Implications for Satellite Geodesy (United States)

    Allenby, R. J.


    Current knowledge and theories of large scale Andean tectonics as they relate to site planning for the NASA Crustal Dynamics Program's proposed high precision geodetic measurements of relative motions between the Nazca and South American plates are summarized. The Nazca Plate and its eastern margin, the Peru-Chile Trench, is considered a prototype plate marked by rapid motion, strong seismicity and well defined boundaries. Tectonic activity across the Andes results from the Nazca Plate subducting under the South American plate in a series of discrete platelets with different widths and dip angles. This in turn, is reflected in the tectonic complexity of the Andes which are a multitutde of orogenic belts superimposed on each other since the Precambrian. Sites for Crustal Dynamics Program measurements are being located to investigate both interplate and extraplate motions. Observing operations have already been initiated at Arequipa, Peru and Easter Island, Santiago and Cerro Tololo, Chile. Sites under consideration include Iquique, Chile; Oruro and Santa Cruz, Bolivia; Cuzco, Lima, Huancayo and Bayovar, Peru; and Quito and the Galapagos Islands, Ecuador. Based on scientific considerations, Santa Cruz, Huancayo (or Lima), Quito and the Galapagos Islands should be replaced by Isla San Felix, Chile; Brazilia or Petrolina, Brazil; and Guayaquil, Ecuador. If resources permit, additional important sites would be Buenaventura and Villavicencio or Puerto La Concordia, Colombia; and Mendoza and Cordoba, Argentina.

  18. 内蒙古苏尼特右旗毕力赫大型斑岩型金矿床辉钼矿Re-Os同位素年龄及其地质意义%Molybdnite Re-Os isotope age of Bilihe large-size porphyry gold deposit in Sunid Right Banner of Inner Mongolia and its geological significance

    Institute of Scientific and Technical Information of China (English)

    卿敏; 葛良胜; 唐明国; 屈文俊; 袁士松; 赵玉锁


    between hypo-volcanic complex body and overlying volcanic rocks as well as volcanic clastic rocks, especially in the inner-contact zone. It is the first time that a large-sized porphyry gold deposit was found in the northern margin of North China plate, i.e., the Bilihe large-size porphyry gold deposit in Sunid Right Banner of Inner Mongolia. In order to identify the porphyry gold (copper) metallogenic age, the authors used Re-Os isotope to test 6 molybdnite samples collected from the porphyry, which yielded the isochron age of (272.7 ± 1.6) Ma (MSWD = 0.57). Redefinition of the late Paleozoic ore-forming geological event of the Bilihe gold deposit has provided new evidence for the convergent plate structural system in the northern part of North China in late Paleozoic, recognized some basic geological problems of the northern part of North China, and given enlightenments in search for low temperature shallow-seated porphyry gold-polymetallic deposits in the magmatic arc environment of the middle-east segments of the Central Asian Orogenic Belt in late Paleozoic.

  19. U-Pb, Re-Os, and 40Ar/39Ar geochronology of the Nambija Au-skarn and Pangui porphyry Cu deposits, Ecuador: implications for the Jurassic metallogenic belt of the Northern Andes (United States)

    Chiaradia, Massimo; Vallance, Jean; Fontboté, Lluis; Stein, Holly; Schaltegger, Urs; Coder, Joshua; Richards, Jeremy; Villeneuve, Mike; Gendall, Ian


    New U-Pb, Re-Os, and 40Ar/39Ar dates are presented for magmatic and hydrothermal mineral phases in skarn- and porphyry-related ores from the Nambija and Pangui districts of the Subandean zone, southeastern Ecuador. Nambija has been one of the main gold-producing centers of Ecuador since the 1980s due to exceptionally high-grade ores (average 15 g/t, but frequently up to 300 g/t Au). Pangui is a recently discovered porphyry Cu-Mo district. The geology of the Subandean zone in southeastern Ecuador is dominated by the I-type, subduction-related, Jurassic Zamora batholith, which intrudes Triassic volcanosedimentary rocks. The Zamora batholith is in turn cut by porphyritic stocks, which are commonly associated with skarn formation and/or porphyry-style mineralization. High precision U-Pb and Re-Os ages for porphyritic stocks (U-Pb, zircon), associated prograde skarn (U-Pb, hydrothermal titanite), and retrograde stage skarn (Re-Os, molybdenite from veins postdating gold deposition) of the Nambija district are all indistinguishable from each other within error (145 Ma) and indicate a Late Jurassic age for the gold mineralization. Previously, gold mineralization at Nambija was considered to be Early Tertiary based on K-Ar ages obtained on various hydrothermal minerals. The new Jurassic age for the Nambija district is slightly younger than the 40Ar/39Ar and Re-Os ages for magmatic-hydrothermal minerals from the Pangui district, which range between 157 and 152 Ma. Mineralization at Nambija and Pangui is associated with porphyritic stocks that represent the last known episodes of a long-lived Jurassic arc magmatism (˜190 to 145 Ma). A Jurassic age for mineralization at Nambija and Pangui suggests that the Northern Andean Jurassic metallogenic belt, which starts in Colombia at 3° N, extends down to 5° S in Ecuador. It also adds a new mineralization style (Au-skarn) to the metal endowment of this belt.

  20. “三江”地区中旬弧普朗成矿斑岩地球化学特征及其成因%Geochemistry and petrogenesis of Pulang porphyries in Sanjiang region

    Institute of Scientific and Technical Information of China (English)

    任江波; 许继峰; 陈建林; 张世权; 梁华英


    Located in Zhongdian island arc belt in northwestern Yunnan Province, the Pulang super large porphyry copper deposit was formed in late Triassic during the westward subduction of the Ganzi-Litang ocean plate below Zhongdian microplate. The mineralized rocks of the Pulang porphyry copper deposit mainly include quartz dioritic porphyries and quartz monzonitic porphyries in a complex pluton, and economic ores are mainly preserved in the quartz monzonitic porphyries. The quartz dioritic porphyrites were intruded by later quartz monzonitic porphyries, but the two kinds of rocks display similar geochemical characteristics, such as similar REE patterns, incompatible trace element patterns and initial 87Sr/86Sr and Nd/144Nd ratios, suggesting that they were coge-netic products or were derived from similar sources. Geochemically, both kinds of rocks are akin to adakite, as evidenced by such characteristics as high Sr content (289×10-6~l 200×10-6), high La/Yb and Sr/Yb ratios, relatively high MgO and Mg# (>59), depleted Y and Yb, slightly negative Eu anomalies and positive Sranomalies Moreover, the radiogenic Sr [0.705 60 61.0%) and K2O (2.2%~4.4%), while the latter have high SiQ2(> 65.9%) and K2O (3.5%~8.1%). Therefore, the authors hold that the Pulang porphyry copper deposit was probably related to the westward subduction of Ganzhi-Litang oceanic plate during late Triassic. At the early stage of subduction, the quartz dioritic porphyries with subduction-related origin were formed firstly, then increasing adakitic magmas of slab melting were mixed with melts from subducted sediments or arc materials, producing more acid and high oxygen fugacity adakitic magmas, which finally intruded the upper crust below Pulang and promoted the mineralization of the Pulang porphyry copper deposit at the shallow level.%普朗斑岩铜矿床是中国西南“三江”地区新发现的具超大规模的印支期斑岩铜矿床,其成矿岩体的斑岩具有高的Sr含量(289×10-6~1 200

  1. Three-dimensional distribution of igneous rocks near the Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska: constraints from regional-scale aeromagnetic data (United States)

    Anderson, Eric D.; Zhou, Wei; Li, Yaoguo; Hitzman, Murray W.; Monecke, Thomas; Lang, James R.; Kelley, Karen D.


    Aeromagnetic data helped us to understand the 3D distribution of plutonic rocks near the Pebble porphyry copper deposit in southwestern Alaska, USA. Magnetic susceptibility measurements showed that rocks in the Pebble district are more magnetic than rocks of comparable compositions in the Pike Creek–Stuyahok Hills volcano-plutonic complex. The reduced-to-pole transformation of the aeromagnetic data demonstrated that the older rocks in the Pebble district produce strong magnetic anomaly highs. The tilt derivative transformation highlighted northeast-trending lineaments attributed to Tertiary volcanic rocks. Multiscale edge detection delineated near-surface magnetic sources that are mostly outward dipping and coalesce at depth in the Pebble district. The total horizontal gradient of the 10-km upward-continued magnetic data showed an oval, deep magnetic contact along which porphyry deposits occur. Forward and inverse magnetic modeling showed that the magnetic rocks in the Pebble district extend to depths greater than 9 km. Magnetic inversion was constrained by a near-surface, 3D geologic model that is attributed with measured magnetic susceptibilities from various rock types in the region. The inversion results indicated that several near-surface magnetic sources with moderate susceptibilities converge with depth into magnetic bodies with higher susceptibilities. This deep magnetic source appeared to rise toward the surface in several areas. An isosurface value of 0.02 SI was used to depict the magnetic contact between outcropping granodiorite and nonmagnetic sedimentary host rocks. The contact was shown to be outward dipping. At depths around 5 km, nearly the entire model exceeded the isosurface value indicating the limits of nonmagnetic host material. The inversion results showed the presence of a relatively deep, northeast-trending magnetic low that parallels lineaments mapped by the tilt derivative. This deep low represents a strand of the Lake Clark fault.

  2. On the Nature of Cross-Linguistic Transfer: A Case Study of Andean Spanish (United States)

    Muntendam, Antje G.


    This paper presents the results of a study on cross-linguistic transfer in Andean Spanish word order. In Andean Spanish the object appears in preverbal position more frequently than in non-Andean Spanish, which has been attributed to an influence from Quechua (a Subject-Object-Verb language). The high frequency of preverbal objects could be…

  3. Critical Factors Controlling Pd and Pt Potential in Porphyry Cu–Au Deposits: Evidence from the Balkan Peninsula

    Directory of Open Access Journals (Sweden)

    Demetrios G. Eliopoulos


    Full Text Available Porphyry Cu–Au–Pd±Pt deposits are significant Au resources, but their Pd and Pt potential is still unknown. Elevated Pd, Pt (hundreds of ppb and Au contents are associated with typical stockwork magnetite-bornite-chalcopyrite assemblages, at the central parts of certain porphyry deposits. Unexpected high grade Cu–(Pd+Pt (up to 6 ppm mineralization with high Pd/Pt ratios at the Elatsite porphyry deposit, which is found in a spatial association with the Chelopech epithermal deposit (Bulgaria and the Skouries porphyry deposit, may have formed during late stages of an evolved hydrothermal system. Estimated Pd, Pt and Au potential for porphyry deposits is consistent with literature model calculations demonstrating the capacity of aqueous vapor and brine to scavenge sufficient quantities of Pt and Pd, and could contribute to the global platinum-group element (PGE production. Critical requirements controlling potential of porphyry deposits may be from the metals contained in magma (metasomatized asthenospheric mantle wedge as indicated by significant Cr, Co, Ni and Re contents. The Cr content may be an indicator for the mantle input.

  4. Postmodern Anthropology: Reflections from Andean Ethnohistory

    Directory of Open Access Journals (Sweden)

    Villarías-Robles, Juan J. R.


    Full Text Available The postmodern perspective, which began its influence on studies of Prehispanic Peru in the 1980s, has resulted —as chief positive effect— in reflection and debate concerning the written sources for apprehending such cultural otherness, the so-called “Chronicles of the West Indies”: a perspective accompanied by new editions of these texts. The author of the present article expresses his own reflection on such change in theory and method. He argues that, with regard to self-reflectivity on its epistemological foundations, the new perspective is not entirely original in the long history of Andean ethnohistory; in effect, this approach is almost as old as the field itself. What is indeed original is the cognitive relativism that surfaced in some extreme forms of the discussion. It was an unfortunate development, however: when not denying, as a matter of principle, the very possibility of understanding that cultural otherness, arguments masked actual interpretations or explanations of its features that were protected, ipso facto, from a rigorous process of validation.

    La perspectiva posmoderna, que empezó a ser influyente en los estudios del Perú prehispánico en la década de 1980, ha tenido como principal efecto positivo la reflexión y el debate sobre las fuentes originales de conocimiento de esa alteridad cultural, las llamadas genéricamente “Crónicas de Indias”: una perspectiva acompañada de nuevas ediciones de tales textos. El autor del presente artículo hace aquí su propia reflexión sobre este cambio teórico y metodológico. Plantea que, en lo que tiene de discusión sobre sus bases epistemológicas, no es del todo original en la larga historia de la etnohistoria peruanista. Es, de hecho, casi tan antiguo como ella. Lo que sí ha sido original es el relativismo cognitivo que ha acompañado a algunas expresiones extremas de la discusión. Pero fue ésta una novedad desafortunada: cuando no negaba por principio la

  5. Copper hypersensitivity. (United States)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P


    The world production of copper is steadily increasing. Although humans are widely exposed to copper-containing items on the skin and mucosa, allergic reactions to copper are only infrequently reported. To review the chemistry, biology and accessible data to clarify the implications of copper hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common. As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak sensitizer as compared with other metal compounds. However, in a few and selected cases, copper can result in clinically relevant allergic reactions.

  6. Andean shrublands of Moquegua, South Peru: Prepuna plant communities

    NARCIS (Netherlands)

    Montesinos, D.B.; Cleef, A.M.; Sykora, K.V.


    A syntaxonomic overview of shrubland vegetation in the southern Andean regions of Peru is presented. For each plant community, information is given on physiognomy, floristic diversity, ecology and geographical distribution. The shrub vegetation on the slopes of the upper Tambo river valley includes

  7. The astronomy of Andean myth: The history of a cosmology (United States)

    Sullivan, William F.

    It is shown that Andean myth, on one level, represents a technical language recording astronomical observations of precession and, at the same time, an historical record of simultaneous social and celestial transformations. Topographic and architectural terms of Andean myth are interpreted as a metaphor for the organization of and locations on the celestial sphere. Via ethoastronomical date, mythical animals are identified as stars and placed on the celestial sphere according to their topographical location. Tested in the planetarium, these arrays generate cluster of dates - 200 B.C. and 650 A.D. Analysis of the names of Wiraqocha and Manco Capac indicates they represent Saturn and Jupiter and that their mythical meeting represents their conjunction in 650 A.D. The astronomy of Andean myth is then used as an historical tool to examine how the Andean priest-astronomers recorded the simultaneous creation of the avllu and of this distinctive astronomical system about 200 B.C. The idea that the agricultural avllu, with its double descent system stressing the importance of paternity, represents a transformation of society from an earlier matrilineal/horticultural era is examined in light of the sexual imagery employed in myth. Wiraqocha's androgyny and the division of the celestial sphere into male (ecliptic) and female (celestial equator = earth) are interpreted as cosmological validations of the new social structure.

  8. Andean grasslands are as productive as tropical cloud forests

    NARCIS (Netherlands)

    Oliveras Menor, I.; Girardin, C.; Doughty, C.E.; Cahuana, N.; Arenas, C.E.; Oliver, V.; Huaraca Huasco, W.; Malhi, Y.


    We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning

  9. Andean Uplift in the Context of Global Climate Change (United States)

    Jeffery, Louise; Poulsen, Chris; Ehlers, Todd; Insel, Nadja


    The two primary causes of South American climate change over the last 40 million years are global climate change and the uplift of the Andes Mountains. Quantifying spatial and temporal variations in climate over the duration of Andean surface uplift is necessary for interpreting palaeoclimate, erosion and palaeoelevation records from the region. This study utilises an atmospheric general circulation model (GCM) to investigate the magnitude and relative importance of 1) global climate and 2) Andean surface uplift to South American climate during the last 40Ma. Combined with knowledge from the geologic record, the results constrain the controls on, and timing of, landscape development. Three different atmospheric CO2 levels (1, 2 and 4x pre-industrial levels - 280ppm) are used to simulate the range of global climate since the early Cenozoic. Surface uplift of the Andes is examined with simulations at three different Andean elevations (100%, 50% and 5% of modern heights). The importance of feedbacks associated with global climate change is assessed with additional simulations incorporating 1) no Antarctic Ice Sheet and 2) an equilibrium vegetation model coupled to the climate model. Initial results show that the elevation of the Andes exerts a much stronger control on South American precipitation than does the atmospheric CO2 level. The presence of the Andes leads to an increase in annual average precipitation rates of up to 8 mm/day at 20⁰S on the eastern flanks of the mountain range. An increase in CO2 levels from 1x to 4x pre-industrial levels increases the intensity of the global hydrological cycle with annual average precipitation rates increasing by up to 5mm/day. At 50% and 5% Andean elevation, precipitation patterns over South America are independent of atmospheric CO2 concentration. However, at 100% Andean elevation South American precipitation is sensitive to high (4x) CO2 levels. Most large-scale circulation patterns over South America are consistent

  10. Timing and duration of hydrothermal activity at the Los Bronces porphyry cluster: an update (United States)

    Deckart, K.; Silva, W.; Spröhnle, C.; Vela, I.


    New geochronological data from the Los Bronces cluster of the Río Blanco-Los Bronces mega-porphyry Cu-Mo district establish a wide range of magmatism, hydrothermal alteration, and mineralization ages, both in terms of areal extent and time. The northern El Plomo and southernmost Los Piches exploration areas contain the oldest barren porphyritic intrusions with U-Pb ages of 10.8 ± 0.1 Ma and 13.4 ± 0.1 Ma, respectively. A hypabyssal barren intrusion adjacent northwesterly to the main pit area yields a slightly younger age of 10.2 ± 0.3 Ma (San Manuel sector, U-Pb), whereas in the Los Bronces (LB) open-pit area, the present day mineral extraction zone, porphyries range from 8.49 to 6.02 Ma (U-Pb). Hydrothermal biotite and sericite ages are up to 0.5 Ma younger but consistent with the cooling of the corresponding intrusion events of each area. Two quartz-molybdenite B-type veins from the LB open pit have Re-Os molybdenite ages of 5.65 ± 0.03 Ma and 5.35 ± 0.03 Ma consistent with published data for the contiguous Río Blanco cluster. The San Manuel exploration area within the Los Bronces cluster, located about 1.5-2 km southeast of the open-pit extraction zone, shows both the oldest hydrothermal biotite (7.70 ± 0.07 Ma; 40Ar/39Ar) and breccia cement molybdenite ages (8.36 ± 0.06 Ma; Re-Os) registered in the entire Río Blanco-Los Bronces district. These are also older than those reported from the El Teniente porphyry Cu(-Mo) deposit, suggesting that mineralization in the late Miocene to early Pliocene porphyry belt of Central Chile commenced 2 Ma before the previously accepted age of 6.3 Ma.

  11. Copper transport. (United States)

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N


    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  12. Copper hypersensitivity

    DEFF Research Database (Denmark)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P


    hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common...

  13. Ages and tectonic significance of the collision-related granite porphyries in the Lhunzhub Basin,Tibet,China

    Institute of Scientific and Technical Information of China (English)

    WANG LiQuan; ZHU DiCheng; GENG QuanRu; LIAO ZhongLi; PAN GuiTang


    The Paleocene collision-related granite porphyries are identified for the first time along the western margin of the Lhunzhub Basin,Tibet.SHRIMP U-Pb zircon analysis indicates that the granite porphyries were emplaced at 58.7±1.1 Ma(MSWD=0.79)during the Indo-Asian continental collision.The granite porphyries are peraluminous and high in K,belonging to the calc-alkaline to high-K calc-alkaline series.They are relatively enriched in LILE,Th and LREE and depletion in Ba,Nb,P and Ti,characterized by LREE-enriched patterns with slightly to moderately negative Eu anomalies.These Paleocene granite porphyries are interpreted as the products generated by partial melting of the pre-existing arc crustal rocks caused by the increase of pressures and temperatures during the crustal shortening at the early stages of the Indo-Asian continental collision since 65 Ma.Despite inherited geochemical features and tectonic settings of the arc protoliths,they are significantly different from the volcanic rocks of the Dianzhong Formation within the Linzizong Group and the Miocene granite porphyries in the Gangdise belt.

  14. Spatial database for a global assessment of undiscovered copper resources: Chapter Z in Global mineral resource assessment (United States)

    Dicken, Connie L.; Dunlap, Pamela; Parks, Heather L.; Hammarstrom, Jane M.; Zientek, Michael L.; Zientek, Michael L.; Hammarstrom, Jane M.; Johnson, Kathleen M.


    As part of the first-ever U.S. Geological Survey global assessment of undiscovered copper resources, data common to several regional spatial databases published by the U.S. Geological Survey, including one report from Finland and one from Greenland, were standardized, updated, and compiled into a global copper resource database. This integrated collection of spatial databases provides location, geologic and mineral resource data, and source references for deposits, significant prospects, and areas permissive for undiscovered deposits of both porphyry copper and sediment-hosted copper. The copper resource database allows for efficient modeling on a global scale in a geographic information system (GIS) and is provided in an Esri ArcGIS file geodatabase format.

  15. Technical analysis of four archaeological andean painted textiles



    This project investigates the materials and manufacturing techniques used to create four archaeological Andean painted textiles in the collection of the National Museum of the American Indian, Smithsonian Institution. The textiles are attributed to Peru but have minimal provenience. Building on previous work by other scholars on similar archaeological textiles, the materials and manufacturing techniques are identified and characterized by observation, documentation, and scientific analysis. S...

  16. Predicting Polylepis distribution: vulnerable and increasingly important Andean woodlands

    Directory of Open Access Journals (Sweden)

    Brian R. Zutta


    Full Text Available Polylepis woodlands are a vital resource for preserving biodiversity and hydrological functions, which will be altered by climate change and challenge the sustainability of local human communities. However, these highaltitude Andean ecosystems are becoming increasingly vulnerable due to anthropogenic pressure including fragmentation, deforestation and the increase in livestock. Predicting the distribution of native woodlands has become increasingly important to counteract the negative effects of climate change through reforestation and conservation. The objective of this study was to develop and analyze the distribution models of two species that form extensive woodlands along the Andes, namely Polylepis sericea and P. weberbaueri. This study utilized the program Maxent, climate and remotely sensed environmental layers at 1 km resolution. The predicted distribution model for P. sericea indicated that the species could be located in a variety of habitats along the Andean Cordillera, while P. weberbaueri was restricted to the high elevations of southern Peru and Bolivia. For both species, elevation and temperature metrics were the most significant factors for predicted distribution. Further model refinement of Polylepis and other Andean species using increasingly available satellite data demonstrate the potential to help define areas of diversity and improve conservation strategies for the Andes.

  17. State dilemmas in applying the Previous Consultation Law in the Andean Region

    Directory of Open Access Journals (Sweden)

    Rafael Barrio de Mendoza


    Full Text Available The Peruvian government enacted a new law granting consultation rights to indigenous peoples as a mechanism to enhance social inclusion in the country. The law generated debates about the criteria to identify indigenous population in the Andean region. Why does this law have problems granting consultation rights to Andean people? This paper aims to answer the question by reviewing historically the different Andean identities and analyzing the current international debate on indigenity. Our main argument is that the government intrying to apply the law is structuring a restrictive model that is hardlyable to grasp the complexity and dynamism of Andean identities.

  18. Lithospheric evolution of the Andean fold thrust belt, Bolivia, and the origin of the central Andean plateau (United States)

    McQuarrie, Nadine; Horton, Brian K.; Zandt, George; Beck, Susan; DeCelles, Peter G.


    We combine geological and geophysical data to develop a generalized model for the lithospheric evolution of the central Andean plateau between 18° and 20° S from Late Cretaceous to present. By integrating geophysical results of upper mantle structure, crustal thickness, and composition with recently published structural, stratigraphic, and thermochronologic data, we emphasize the importance of both the crust and upper mantle in the evolution of the central Andean plateau. Four key steps in the evolution of the Andean plateau are as follows. 1) Initiation of mountain building by ˜70 Ma suggested by the associated foreland basin depositional history. 2) Eastward jump of a narrow, early fold-thrust belt at 40 Ma through the eastward propagation of a 200-400-km-long basement thrust sheet. 3) Continued shortening within the Eastern Cordillera from 40 to 15 Ma, which thickened the crust and mantle and established the eastern boundary of the modern central Andean plateau. Removal of excess mantle through lithospheric delamination at the Eastern Cordillera-Altiplano boundary during the early Miocene appears necessary to accommodate underthrusting of the Brazilian shield. Replacement of mantle lithosphere by hot asthenosphere may have provided the heat source for a pulse of mafic volcanism in the Eastern Cordillera and Altiplano at 24-23 Ma, and further volcanism recorded by 12-7 Ma crustal ignimbrites. 4) After ˜20 Ma, deformation waned in the Eastern Cordillera and Interandean zone and began to be transferred into the Subandean zone. Long-term rates of shortening in the fold-thrust belt indicate that the average shortening rate has remained fairly constant (˜8-10 mm/year) through time with possible slowing (˜5-7 mm/year) in the last 15-20 myr. We suggest that Cenozoic deformation within the mantle lithosphere has been focused at the Eastern Cordillera-Altiplano boundary where the mantle most likely continues to be removed through piecemeal delamination.

  19. Geology and ore fluid geochemistry of the Jinduicheng porphyry molybdenum deposit, East Qinling, China (United States)

    Li, Hongying; Ye, Huishou; Wang, Xiaoxia; Yang, Lei; Wang, Xiuyuan


    Jinduicheng deposit is a giant Mesozoic porphyry Mo system deposit in the East Qinling molybdenum belt, Shaanxi Province, China. The mineralization is associated with the I-type Jinduicheng granite porphyry. Both the porphyry stock and country rocks underwent intense hydrothermal alteration. The alteration, with increasing distance from the parent intrusion, changes from silicification, through potassic and phyllic assemblages, carbonation, to propylitic assemblages. Molybdenite, the dominant ore mineral, occurs in veinlets, most of which are hosted by the altered country rocks, with less than 25% of the ore in the porphyry body. The hydrothermal system comprises four stages, including pre-ore quartz and K-feldspar; two ore stages of quartz, K-feldspar, molybdenite, and Pb- And Zn-bearing sulfides; and post-ore quartz and carbonate. Six main types of primary fluid inclusions are present in hydrothermal quartz, including two-phase aqueous, one-phase aqueous, three-phase CO2-bearing, CO2-dominated fluid inclusions, gas inclusions, and melt inclusions. The homogenization temperatures of fluid inclusions range from 210 to 290 °C in the pre-ore stage, 150-310 °C in ore stage I, 150-360 °C in the ore stage II, and 195-325 °C in the post-ore stage quartz. Estimated salinities of the ore-forming fluids range from 6.9 to 13.5, 4.3 to 12.3, 6.2 to 12.4, and 3.4 to 9.9 wt.% NaCl equiv. in stages 1-4, respectively. The δ34S values of pyrite in the two ore stages range from 2.8‰ to 4.3‰, whereas the δ34S values of molybdenite range from 2.9‰ to 6.2‰. The data suggest both magmatic and crustal sources of sulfur. The δD and δ18O values for the hydrothermal fluids are -57.2‰ to -84.4‰ and 8.0‰ to -3.2‰, respectively. The fluid inclusion and stable data indicate that the pre-ore hydrothermal fluids were mostly of magmatic origin, but the fluids responsible for ore deposition were mixed magmatic and meteoric, and eventually meteoric water dominated the system

  20. SEM-Cathodoluminescence and fluid inclusion study of quartz veins in Hugo Dummett porphyry Cu-Au deposit,South Mongolia (United States)

    Sanjaa, M.; Fujimaki, H.; Ken-Ichiro, H.


    The Hugo Dummett porphyry copper-gold deposit in Oyu Tolgoi, South Mongolia is a high-sulfidation type deposit which consists of Cu-Au bearing quartz veins. Cathodoluminescence (CL) analysis using scanning electron microscope (SEM) and fluid inclusion microthermometer were performed to elucidate the relationship between CL structures, fluid inclusion microthermometer of different quartz generations, and ore forming process of the Hugo Dummett deposit. Hydrothermal quartz from quartz-sulfide veins in the porphyry Cu-Au deposit in Hugo Dummett, revealing the following textures: (1) euhedral growth zones (2) embayed and rounded CL-bright cores, with CL-dark and CL-gray overgrowths, (3) concentric and non concentric growth zones, and (4) CL dark/bright microfractures. These textures indicate that many veins have undergone fracturing, growth of quartz into fluid-filled space and quartz dissolution of quartz. SEM-CL imaging indicates vein quartz in the Hugo Dummett deposit, initially grew as individual CL-bright crystals 356 ± 10°C liquid-reservoir (average Th value for fluid inclusions in the crystal cores is 359°C). In contract, SEM-CL imaging shows the edges of the micron-scale growth zones of varying CL intensity, reflecting quartz precipitation at some later time, when the Hugo Dummett deposit hydrothermal system had cooled, when reservoir conditions were about 211 ± 25°C (average Th value of 212°C). Crystal growth is SEM-CL evidence of the vein quartz having been partly dissolved. Pressure change has a large effect on quartz solubility and may have been responsible for quartz dissolution and precipitation textures in the cooling hydrothermal system. CL-dark microfractures homogenization temperatures lower 169 ± 16°C (average Th value 170°C) than CL bright and CL gray. Temperature and pressure of the mineralized fluid estimates a pressure of formation of 0.3-0.5 kbar (lithostatic), was formed at approximately 2 km depth, as well as a formation temperature

  1. Partial melting of subducted paleo-Pacific plate during the early Cretaceous: Constraint from adakitic rocks in the Shaxi porphyry Cu-Au deposit, Lower Yangtze River Belt (United States)

    Deng, Jianghong; Yang, Xiaoyong; Li, Shuang; Gu, Huangling; Mastoi, Abdul Shakoor; Sun, Weidong


    A large porphyry Cu-Au deposit associated with early Cretaceous intrusive rocks has been discovered and explored in the Shaxi area, Lower Yangtze River Belt (LYRB), eastern China. We studied two types of intrusive rocks in the Shaxi area: Cu-Au mineralization related diorites and quartz-diorites (adakitic rocks), and newly found high Sr/Y ratio biotite-gabbros. They were formed almost simultaneously with crystallization ages of ca. 130 to 129 Ma, younger than the early stage shoshonitic rocks (Longmenyuan, Zhuanqiao and Shuangmiao Fm.) in the Luzong volcanic basin, ~ 10 km south of the Shaxi area. These intrusive rocks show similar distribution patterns of trace elements (enriched in LILEs and depleted in HFSEs) and REEs (enriched in LREEs and depleted in HREEs, no Eu negative anomaly, flat HREE patterns). The diorites and quartz-diorites are adakitic rocks with calc-alkaline affinity, distinguished from other adakitic rocks in the LYRB which are high-K calc-alkaline series. The biotite-gabbros are not adakitic rocks, although they are characterized by high Sr/Y ratios. Shaxi adakitic rocks show positive zircon εHf(t) values, which may be attributed to the contribution of subducted oceanic crust, while the εHf(t) values of the biotite-gabbros are mostly negative, indicating the involvement of old crustal materials. Although Sr-Nd-Pb isotopes of Shaxi adakitic rocks are more depleted than those of other adakitic rocks in the LYRB, they are still slightly enriched, similar to continental arc adakites in the Andean Austral Volcanic Zone. The Shaxi adakitic rocks are characterized by high Sr contents and Sr/Y ratios, medium (La/Yb)N, MgO contents and Mg#, and low K2O/Na2O ratios, decoupling of Sr/Y and (La/Yb)N, low Th/U values, exhibiting characteristics of slab-derived adakitic rocks. They were not produced by fractional crystallization of basaltic magmas like adakitic rocks in Edong-Jiurui and Tongling but originally generated from partial melting of subducted

  2. Ordovician Intrusive-related Gold-Copper Mineralization in West-Central New South Wales, Australia

    Institute of Scientific and Technical Information of China (English)


    Three major types of Ordovician intrusive-related gold-copper deposits are recognized in central-west New South Wales,, Australia: porphyry, skam and high sulphidation epithermal deposits.These deposits are mainly distributed within two Ordovician volcano-intrusive belts of the Lachlan Fold Be1t: the Orange-Wellington Belt and the Parkes-Narromine Belt. Available isotopic age data suggest that mineralization of the three types of deposits is essentially coeval with the Ordovician intrusive rocks (480-430 Ma). Porphyry gold-copper deposits can be further divided into two groups. The first group is associated with monzoniteshowing shoshonitic features represented by Cadia and Goonumbla. The second group is associated with diorite and dacite, including the Copper Hill and Cargo gold-copper deposits. Gold skarn is associated with Late Ordovician (430-439 Ma) monzonitic intrusive complexes in the Junction Reefs area (Sheahan-Grants, Frenchmans, and Cornishmens), Endeavour 6, 7 and 44, Big and Little Cadia. The epithermal gold deposits with high sulphidation including Gidginbung (Temora) and Peak Hill mainly occur within Ordovician andesite and volcaniclastic rocks, and are associated with advanced argillic alteration. Available isotopic age data indicate that both alteration and mineralization of the porphyry, skam and epithermal gold-copper deposits are broadly coeval with the Late Ordovician hoshonitic mangmatism, which is thought to result from the melting of sub-continental lithosphere caused by Palaeozoic subduction events. The Ordovician intrusive-related gold-copper deposits are restricted to two longitudinal parallel volcano-intrusive belts, rarely extending outside them. Diagonal intra-belt trends of mineralization are common, particularly at the intersections of longitudinal and transverse (oblique) fault/fracture zones basedon the authors'review of available geological data. The locations of these gold-copper deposits are obviously influenced by transverse

  3. The Laramide Mesa formation and the Ojo de Agua caldera, southeast of the Cananea copper mining district, Sonora, Mexico (United States)

    Cox, Dennis P.; Miller, Robert J.; Woodbourne, Keith L.


    The Mesa Formation extends from Cananea, Mexico, southeast to the Sonora River and is the main host rock of Laramide porphyry copper deposits in the Cananea District and at the Alacran porphyry prospect to the east. The Mesa consists of two members-a lower andesite and an upper dacite. The lowest part of the dacite member is a crystal tuff about 100 m thick. This tuff is the outfall of a caldera centered near the village of Ojo de Agua, dated by 40Ar/39Ar at 65.8 Ma ?0.4. The Ojo de Agua Caldera is about 9 km in diameter and is filled by a light gray biotite dacite tuff with abundant flattened pumice fragments. The volume of the caldera is estimated to be 24 km3.

  4. Petrogenesis of skarn related Cu-porphyry intrusion deposit, Ali-Abad- Darreh Zereshk, Yazd

    Directory of Open Access Journals (Sweden)

    Batoul Taghipour


    Full Text Available The study area is a part of Cenozoic magmatic belt of Central Iran, which is located in the West of Yazd porovince. Contact metamorphism and skarn occurred in conglomerate part of Sngestan Formation. The Oligocene intrusion bodies of Ali-Abad-Darreh Zereshk are leucocerate and have the chemical composition of granite to granodiorite with calc-alkaline affinity from volcanic arc geological setting. The main mineral assemblage of skarn in order of imprtance is as follow: Garnet + epidote + quartz + calcite + pyrite + iron oxides. Brown garnets are the skarn characteristic mineral. EPMA analysis has shown that the chemical composition with garnet belong to andradite-grossular solid-solution (And 65, Gross 30 with more andradite component. The high permeability and presence of carbonate pebbles in conglomerate are two important factors for fluid flow and genesis of garnets. Distinct oscillatory zoning in garnets is resulted from the change of fO2 in fluids. The evolution of Ali-Abad skarn is took place in the range of 380 to 530 ºC, 0.5 Kbar pressure and high fO2. Also close association of this skarn with Ali-Abad intrusive with Cu-porphyry mineralization shows that this skarn is a Cu-porphyry type skarn.

  5. REE characteristics and genesis of alkaline-rich porphyry, Yunnan Province

    Institute of Scientific and Technical Information of China (English)


    The Yunnan Himalayan alkaline-rich porphyry occurs as a compound rockbelt and consists of calca-alkalic, alkaline and peralkaline intrusions. Its origin is in debate. The paper deals with its origin by studying rock′s REE and Sr isotope. Although the rocks are different in their REE contents varying from 77.53 μg/g to 1 798.3 μg/g, they have very similar features in REE parameters. On the triangalar diagram of REEs, the sample dots are concentrated on the end area of light REEs, representing a product of low-degree melting of upper mantle or lower crust materials. The initial 87Sr/86Sr values of rocks vary between 0.706 4 and 0.709 8, showing a feature of mantle-crust mixed source. Moreover, REEs show a logarithmic linear positive correlation between them. This type of correlation strongly supports the fractional-partial melting model. The result of geochemistry inversion shows that the source rock of alkaline-rich porphyry is plagioclase-bearing harzburgite and of mantle-crust mixed type. At the early state of melting, some crust components of the source rock were partially melted into intermediate-acidic magma; with the crust components consumed, the magma evolved to basic.

  6. Metals and altitude drive genetic diversity of chironomids in Andean streams

    NARCIS (Netherlands)

    Loayza-Muro, R.A.; de Baat, M.; Palomino, E.J.; Kuperus, P.; Kraak, M.H.S.; Admiraal, W.; Breeuwer, H.


    1. Andean streams cover steep altitude gradients and locally leach metal-rich bedrock, creating highly selective habitat conditions. Chironomids are among the few dominant insect taxa present under the harshest conditions in Andean high altitude streams, but it remains unclear whether their dominanc

  7. Imperial porphyry from Gebel Abu Dokhan, the Red Sea Mountains, Egypt

    DEFF Research Database (Denmark)

    Makovicky, Emil; Frei, Robert; Karup-Møller, Sven;


    -K calc-alkaline andesites and dacites with a traceelement spectrum typical of volcanic rocks from an Andean subduction-zone setting. Four rock samples yielded an errorchron with an age of 560 ± 42 Ma and an initial 87Sr/86Sr ratio of 0.70283 ± 0.00011. Using Nd isotope data, values of TDM from 0.84 to 0...

  8. Iron concretions within a highly altered unit of the Berlins Porphyry, New Zealand: an abiotic or biotic story? (United States)

    Cox, Toni L.; Oze, Christopher; Horton, Travis W.


    The Berlins Porphyry located on the South Island of New Zealand provides an opportunity to examine iron concretions formed in a subterranean system. Specifically, an alteration zone within the Berlins Porphyry contains iron concretions similar to sedimentary biologically-mediated iron concretions. Here, we provide evidence for two sources of dissolved Fe (II) that potentially aided in the formation of the iron concretions. Furthermore, we discuss the potential for microbial involvement in the anaerobic oxidation of Fe (II) to Fe (III) to form magnetite. Evidence in support of this hypothesis includes the low concentrations of iron and sulfur in the white hydrothermally altered porphyry outcrop and concretion cores; concentrated pyrite and magnetite mineralisation surrounding the cores; and δ13C values indicative of organic carbon (averaging -26 ‰ ± 4 ‰) within the iron cement, porphyry-core-boundary and outer weathered rinds of the concretions. Overall, these unusually preserved iron concretions could represent a new environmental niche for microorganisms and a potential analogue for microbially induced iron-oxidation. More importantly, this study illustrates the many obstacles involved in analysing and interpreting potential subterranean biosignatures.

  9. Paleomagnetism and the Alpine tectonics of Eurasia U the magnetism of the Permian porphyries near Lugano (Northern Italy, Switzerland)

    NARCIS (Netherlands)

    Hilten, D. van; Zijderveld, J.D.A.


    The magnetic properties of 25 oriented samples of the Permian porphyries from the Lugano district are investigated. After a.c. demagnetization (up to 900 Oe peak value) eleven samples produce a characteristic direction of magnetization, declination (D) = N 143.5°E, inclination (I) = −17°. The other

  10. Geochemical Charactristics and Genesis of Topaz—Bearing Porphyries in Yangbin Area of Taishun County,Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    王德滋; 刘昌实; 等


    The host rocks of the porphyry tin deposits in the Yangbin area are prince-pally topaz-bearing porphyry dikes about 2 km long and 2-20m wide.Three lithologic types are identified for the dikes:topaz-bearing potassium feldspar granitic porphyry,topaz-bearing monzonitic granitic porphyry and topaz-bearing quartz porphyry.The con-tent of topaz in the rocks ranges from 10 to 20 vol.%.Porphyritic texture is characteristic,with quartz,potassium feldspar and albite as main phenocryst minerals.The phenocryst occupies 10-20vol% of the rocks.The rock groundmass consists of subhedrak topaz,quartz and protolithionite.Topaz has a unit-cell parameter b=8.797(A)°,and F:OH=1.92:0.18, indicating a F-rich variety formed at high temperature .The topaz-bearing porphyries occurring in this area are strongly peraluminous (A/NKC=1.574-12.94),with high ra-tios of F/C1(146-303) and Rb/Sr(5-122).They are rich in incompatible elements (Sn,313×10-6-1042×10-6;W,6×10-6-218×10-6;Nb,27×10-6-54×10-6),but poor in compatible elements (Sr,10×10-6-28×10-6;Ba,58×10-6-73×10-6;V,3×10-6-10×10-6,Cl,150×10-6-226×10-6).The rocks are also characterized by high total REE amount (281.69×10-6-319.76×10-6);with strong Eu depletion (&Eu=0.01-0.03)and low ratio of LREE/HREE(0.78-0.84).In summary ,the authors propose propose an idea of S-type genesis for the topaz-bearing porphyries with tin mineralization,instead of I-type.

  11. A Long-Lived Porphyry Ore Deposit and Associated Upper Crustal Silicic Magma Body, Bajo de la Alumbrera, Argentina (United States)

    Harris, A. C.; Allen, C. M.; Reiners, P. W.; Dunlap, W. J.; Cooke, D. R.; Campbell, I. H.; White, N. C.


    Porphyry Cu deposits form within and adjacent to small porphyritic intrusions that are apophyses to larger silicic magma bodies that reside in the upper parts of the Earth's crusts. Centred on these intrusions are hydrothermal systems of exsolved magmatic fluid with a carapace of convectively circulating meteoric water. We have applied several different dating techniques to assess the longevity of the magmatic-hydrothermal system and to define the cooling history of porphyry intrusions at the Bajo de la Alumbrera porphyry Cu-Au deposit, Argentina. The closure temperatures of these techniques range from 800oC (zircon U-Pb) to ~70oC (apatite (U-Th)/He; Fig. 1). The resulting cooling history indicates that the magmatic-hydrothermal system cooled to ca. 200oC by ~1.5 m.y. after the last porphyry intrusion (i.e., 6.96±0.09 Ma; U-Pb zircon age). Based on (U-Th)/He apatite data (closure temperature ~60-70oC), exposure and cessation of the system occurred before 4 Ma. The longevity of the magmatic-hydrothermal system indicated by these results is inconsistent with accepted mechanisms for porphyry Cu deposit formation. Depending on wallrock permeability, depth and cooling method, a 2 km wide by 3 km high intrusion has been predicted to cool between 0.01 to 0.1 m.y. (marked as the grey interval; Cathles et al., 1997 Economic Geology). We have obtained numerous age determinations younger than the U-Pb zircon age of the last known intrusion at Bajo de la Alumbrera. These imply that simple cooling of the small, mineralized porphyries did not happen. For the magmatic-hydrothermal system to have been sustained for longer than 0.1 m.y., either 1) younger small intrusions have been episodically emplaced below the youngest known intrusions, thus prolonging heat flow, or 2) fluids derived from a deeper and larger parental intrusion have been episodically discharged through the ore deposit long after the porphyry intrusion had lost its available heat. In either case, the longevity of

  12. Integration, migration and sustainable development in the Andean group of nations. (United States)

    Leon, R; Kratochwil, H


    This paper, which was presented at the 1993 meeting of the International Organization for Migration, summarizes past and recent progress in Andean integration and migration arrangements. Changes in the strategy of the Andean group of nations (GAN) have occurred in the adjustment to prevailing conditions at the subregional and international level. GAN includes Bolivia, Colombia, Ecuador, Peru, and Venezuela. The Andean Pact originated with the signing of the Cartegena Agreement in 1969. Members approved the Andean Strategic Design in 1989, which loosened up trade integration and the movement of capital, services, and persons across shared borders. The Strategic Design also addressed issues resulting from economic and social integration. A statement of migratory patterns among GAN, Andean integration during 1969-89, and the goals and operation of the Andean Strategic Design and integration are discussed in some detail. The Galapagos Declaration and the La Paz Statement of 1990 are also described. The present situation with Andean integration is based on the following meetings of Andean nations: the First Meeting of Migration Officials of the Andean Group of Nations in March 1991, the Second Meeting of Migration Officials in September 1991, and bilateral agreements between Andean nations. Seven basic conclusions are drawn: 1) the strategy is an institutional, deliberate, programmed process; 2) integration within GAN is the culmination of a joint, coordinated directive of achievement of sustainable development in the subregion which aims to reduce the economic gaps between the North and the South, to lessen the impact of protected markets of the North and their migration barriers, and to improve the possibility of development of technologically sophisticated human capital; 3) subregional policies are more sensitive to short-term change in domestic politics; 4) integration and migration can be sustained better with deliberate planning; 5) implementation is dependent on

  13. Geochemical and Sr-Pb-Nd isotopic characteristics of the Shakhtama porphyry Mo-Cu system (Eastern Transbaikalia, Russia) (United States)

    Berzina, A. P.; Berzina, A. N.; Gimon, V. O.


    The Shakhtama Mo-Cu porphyry deposit is located within the eastern segment of the Central Asian Orogenic Belt, bordering the southern margin of the Mongol-Okhotsk suture zone. The deposit includes rocks of two magmatic complexes: the precursor plutonic (J2) and ore-bearing porphyry (J3) complexes. The plutonic complex was emplaced at the final stages of the collisional regime in the region; the formation of the porphyry complex may have overlapped with a transition to extension. The Shakhtama rocks are predominantly metaluminous, I-type high K calc-alkaline to shoshonitic in composition, with relatively high Mg#, Ni, Cr and V. They are characterized by crustal-like ISr (0.70741-0.70782), relatively radiogenic Pb isotopic compositions, ɛNd(T) values close to CHUR (-2.7 to +2.1) and Nd model ages from 0.8 to 1.2 Ga. Both complexes are composed of rocks with K-adakitic features and rocks without adakite trace element signatures. The regional geological setting together with geochemical and isotopic data indicate that both juvenile and old continental crust contributed to their origin. High-Mg# K-adakitic Shakhtama magmas were most likely generated by partial melting of thickened lower crust during delamination and interaction with mantle material, while magmas lacking adakite-like signatures were probably generated at shallower levels of lower crust. The derivation of melts, related to the formation of plutonic and porphyry complexes involved variable amounts of old Precambrian lower crust and juvenile Phanerozoic crust. Isotopic data imply stronger contribution of juvenile mantle-derived material to the fertile magmas of the porphyry complex. Juvenile crust is proposed as an important source of fluids and metals for the Shakhtama ore-magmatic system.

  14. SENP1, but not fetal hemoglobin, differentiates Andean highlanders with chronic mountain sickness from healthy individuals among Andean highlanders. (United States)

    Hsieh, Matthew M; Callacondo, David; Rojas-Camayo, Jose; Quesada-Olarte, Jose; Wang, Xunde; Uchida, Naoya; Maric, Irina; Remaley, Alan T; Leon-Velarde, Fabiola; Villafuerte, Francisco C; Tisdale, John F


    Chronic mountain sickness (CMS) results from chronic hypoxia. It is unclear why certain highlanders develop CMS. We hypothesized that modest increases in fetal hemoglobin (HbF) are associated with lower CMS severity. In this cross-sectional study, we found that HbF levels were normal (median = 0.4%) in all 153 adult Andean natives in Cerro de Pasco, Peru. Compared with healthy adults, the borderline elevated hemoglobin group frequently had symptoms (headaches, tinnitus, cyanosis, dilatation of veins) of CMS. Although the mean hemoglobin level differed between the healthy (17.1 g/dL) and CMS (22.3 g/dL) groups, mean plasma erythropoietin (EPO) levels were similar (healthy, 17.7 mIU/mL; CMS, 12.02 mIU/mL). Sanger sequencing determined that single-nucleotide polymorphisms in endothelial PAS domain 1 (EPAS1) and egl nine homolog 1 (EGLN1), associated with lower hemoglobin in Tibetans, were not identified in Andeans. Sanger sequencing of sentrin-specific protease 1 (SENP1) and acidic nuclear phosphoprotein 32 family, member D (ANP32D), in healthy and CMS individuals revealed that non-G/G genotypes were associated with higher CMS scores. No JAK2 V617F mutation was detected in CMS individuals. Thus, HbF and other classic erythropoietic parameters did not differ between healthy and CMS individuals. However, the non-G/G genotypes of SENP1 appeared to differentiate individuals with CMS from healthy Andean highlanders.

  15. Climate change forces new ecological states in tropical Andean lakes.

    Directory of Open Access Journals (Sweden)

    Neal Michelutti

    Full Text Available Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, remain largely unknown. Here, we show that recent climate changes have forced alpine lakes of the equatorial Andes towards new ecological and physical states, in close synchrony to the rapid shrinkage of glaciers regionally. Using dated sediment cores from three lakes in the southern Sierra of Ecuador, we record abrupt increases in the planktonic thalassiosiroid diatom Discostella stelligera from trace abundances to dominance within the phytoplankton. This unprecedented shift occurs against the backdrop of rising temperatures, changing atmospheric pressure fields, and declining wind speeds. Ecological restructuring in these lakes is linked to warming and/or enhanced water column stratification. In contrast to seasonally ice-covered Arctic and temperate alpine counterparts, aquatic production has not increased universally with warming, and has even declined in some lakes, possibly because enhanced thermal stability impedes the re-circulation of hypolimnetic nutrients to surface waters. Our results demonstrate that these lakes have already passed important ecological thresholds, with potentially far-reaching consequences for Andean water resources.

  16. Andean rural children's views of the environment: A qualitative study (United States)

    Maurial, Mahia

    Andean rural children's drawings and narratives about their crops and the immediate biological environment are rich tools to understand local views of the environment. Children's drawings and narratives were collected and linked to interviews as well as participant observation gathered from parents, leaders and teachers. The research sites are the community of Willca and the school of Mayu. Fieldwork was completed in 1998. In the conceptual framework I distinguish between two dissimilar knowledges, school knowledge and local knowledge. These knowledges produce two dissimilar views of the environment. I further analyze relationships of knowledge and power and argue that school knowledge overpowers local knowledge. Concomitantly, I studied set of ideas associated with two knowledges aforementioned: superacion (surpass) and regeneration (Apffel-Marglin 1995). Although these ideas coexist in peoples' minds they are not linked or effectively connected. In order to link local knowledge and school knowledge together, I propose the integration of environmental studies and art education to enhance a local sense of place (Blandy et. al 1993) in Andean and other schools. This will contribute to grassroots educational policy.

  17. Geological Characteristics of the Mingze Porphyry Molybdenum Deposit and Prospecting Prognosis in Its Adjacent Area,Shannan,Tibet%西藏山南明则矿区斑岩型钼矿地质特征及外围找矿预测

    Institute of Scientific and Technical Information of China (English)

    陈玉水; 王成东; 杜庆安


    西藏山南明则矿区斑岩型钼矿床主要由一厚大隐伏的钼矿体组成,其上部覆盖着巨厚层的古近系罗布莎群磨拉石建造.矿床赋存于冈底斯-念青唐古拉板片与喜马拉雅板片的结合带附近,赋矿岩石为钾长花岗岩和二长花岗斑岩.自上而下递次出现青盘岩化、泥化、(黄铁)绢云母化或石英钾化带.岩体侵入时代为古近纪渐新世.辉钼矿Re-Os同位素等时线年龄值为30Ma.该矿的发现为冈底斯成矿带南缘寻找同类斑岩型钼(铜)矿提供了新的线索.%The Mingze porphyry molybdenum deposit in Shannan, Tibet, is mainly composed of concealed massive molybdenum orebodies, which are covered by thick Paleogene Luobusa molasse. It lies in the suture zone between the Gangdise - Nyainqentanglha plate and the Himalayan plate. The deposit is hosted in K-feldspar granite and monzonitic granite-porphyry. From the top to the bottom of the orebody, alteration varies from propylitic alteration, argillization, phyllite-like alteration, pyritization to silicifiration and potassic alteration. The age of intrusive rock is Paleogene Oligocene, and the Re-Os isotope age of molybdenite ore is 30Ma. The discovery of the Mingze deposit provides new helpful evidence for prospecting similar porphyry molybdenum (copper) deposit along the southern margin of the Gangdise metallogenic belt.

  18. Porphyry copper assessment of British Columbia and Yukon Territory, Canada: Chapter C in Global mineral resource assessment (United States)

    Mihalasky, Mark J.; Bookstrom, Arthur A.; Frost, Thomas P.; Ludington, Steve


    The U.S. Geological Survey does regional, national, and global assessments of resources (mineral, energy, water, biologic) to provide science in support of land management and decision making. Mineral resource assessments provide a synthesis of available information about where mineral deposits are known and suspected to be in the Earth’s crust, which commodities may be present, and estimates of amounts of resources that may be present in undiscovered deposits.

  19. Geological Characteristics of Copper Mineralization,Jiujiang—Ruichang Area,Jiangxi Province,China

    Institute of Scientific and Technical Information of China (English)

    邱小平; 裴荣富; 等


    The Jiujiang-Ruichang area in northwestern Jiangxi extends along the western part of the minerogenic belt of the middle-lower Yangtze Valley in a terrain of sediments ranging from Ordovician to Triassic in age with NEE-folda,and NW-compressive,NNW-tensile and NEE-compressive-shearing faults as the major structures .Igneous rocks are mostly intermediate-acid epizonal intrusive bodies.Typical copper mineralizations in this area include the skarn-type and stratiform Cu-bearing pyrite-type deposits at Wushan and the porphyry and breccia-pipe type copper-molybdenum deposits at Chengmenshan.Silurian strata,with a great thickness and an average copper content of 51 ppm,are considered to be the source bed of copper mineralization,as is evidenced,among other things,by the presence of an envelope which is notably impoverished in Cu aroud most of the deposits.Magmatic rocks which intruded into the Silurian strata often have relatively high alkali contents and K2O/Na2O ratios ,with extensive potash alteration.Magmatic rocks in the area are of co-melting type or mixed type.The magma assimilated a large quanity of country rocks while ascending.They are characterized by high REE contents,absence of Eu anomalies and high LREE/HREE ratios.Ancient lead and strontium isotopes were detected in feldspar megaphenocrysts from the granodiorite porphyry.Hydrothermal convective circulation systems of magmatic water of magmatic water and supergenic water was extensively developed in the magmatic and country rocks,in which copper,potassium and other ore-forming components were extracted from the country rocks and concentrated through heating,boiling and evaporating.When the ore-forming fluids found their way into the skarn zone or the unconformity between the Wutong Formation and the Huanglong Formation,ore precipitation would have occurred as a result of changing media,If the concentration of KCl exceeded 9%,copper and other ore-forming components might have been deposited in magmatic rocks

  20. Recycling of Proterozoic crust in Pleistocene juvenile magma and rapid formation of the Ok Tedi porphyry Cu-Au deposit, Papua New Guinea (United States)

    van Dongen, M.; Weinberg, R. F.; Tomkins, A. G.; Armstrong, R. A.; Woodhead, J. D.


    We present an investigation of the combined U-Pb, O and Hf isotope composition of zircons from a giant porphyry copper-gold deposit, hosted in a shoshonitic intermediate intrusive complex of the Ok Tedi area in Papua New Guinea. This area is part of a Late Miocene-Pliocene collisional fold-and-thrust belt related to island arc accretion to the Australian plate. Cathodoluminescence and transmitted light imaging reveal distinct zircon textures such as spongy rims and inherited zircon cores. Spongy textures, interpreted to result from corrosion of the surface by hydrothermal fluids, do not seem to affect the U-Pb, O and Hf isotope composition. Calculated SHRIMP U-Pb ages for the rims are 1.1-1.4 Ma whereas the inherited component is ~ 1.8 Ga. Our age results combined with existing K-Ar results, constrain the formation of the Ok Tedi deposit to Oxygen isotope composition (δ 18O), measured by SHRIMP, is ~ 6.5‰ for Pleistocene zircons but extend to values of ~ 8.3‰ or more for Proterozoic zircon cores. Likewise, corrected Hf isotope ratios from LA-ICP-MS analyses are centred on 0.2825 ( ɛHf(t) = - 6.5 ± 2) for Pleistocene zircons, compared to ~ 0.2815 ( ɛHf(t) = + 5 to - 3) for Proterozoic components. The Pleistocene zircon isotope signature is best explained by assimilation of Proterozoic crustal source material into asthenospheric mantle-derived magma similar to that of the Pliocene Porgera Au-only deposit in the same orogen.

  1. Zircon U-Pb geochronology, geochemistry, and Sr-Nd-Hf isotopes of granitoids in the Yulekenhalasu copper ore district, northern Junggar, China: Petrogenesis and tectonic implications (United States)

    Yang, Fuquan; Chai, Fengmei; Zhang, Zhixin; Geng, Xinxia; Li, Qiang


    The Yulekenhalasu porphyry copper deposit is located in the Kalaxiange'er metallogenic belt in northern Junggar, China. We present the results from zircon U-Pb geochronology, and geochemical and Sr-Nd-Hf isotope analyses of the granitoids associated with the ore deposits with a view to constrain their petrogenesis and tectonic setting. The granitoids consist of quartz diorite, diorite porphyry, porphyritic monzonite, and quartz porphyry, emplaced at 382, 379, 375-374, and 348 Ma, respectively, which span Late Devonian to early Carboniferous ages. The ore-bearing intrusion is mainly diorite porphyry, with subordinate porphyritic monzonite. The Late Devonian intrusions are characterized by SiO2 contents of 54.5-64.79 wt.%, Na2O contents of 3.82-8.24 wt.%, enrichment in Na, light rare-earth elements (LREEs), and large ion lithophile elements. They also display relative depletion in Y, Ba, P, Nb, Ta, and Ti, and weak negative Eu anomalies (δEu = 0.6-0.87). The early Carboniferous quartz porphyry is characterized by high SiO2 content (72.26-73.35 wt.%), enrichment in LREEs, K, and Sr, and relative depletion in Y (10.82-12.52 ppm) and Yb (1.06-1.15 ppm). The Late Devonian and early Carboniferous granitoids are characterized by positive ɛNd(t) values (5.2-10.1, one sample at - 1.9), positive ɛHf(t) values (7.46-18.45), low (87Sr/86Sr)i values (0.70363-0.70476), and young crustal residence ages. These data indicate that the sources of the granitoids were mainly mantle-derived juvenile rocks. Geochemical and Nd-Sr-Hf isotopic data demonstrate that the Late Devonian granitoids formed in an oceanic island arc, and they were formed from different sources, among which the mineralized diorite porphyry might have originated from a mixed slab-derived and mantle wedge melt source. The early Carboniferous quartz porphyry was likely emplaced in a mature island arc environment, and was probably derived from juvenile crust.

  2. Forward modeling of δ18O in Andean ice cores (United States)

    Hurley, J. V.; Vuille, M.; Hardy, D. R.


    Tropical ice core archives are among the best dated and highest resolution from the tropics, but a thorough understanding of processes that shape their isotope signature as well as the simulation of observed variability remain incomplete. To address this, we develop a tropical Andean ice core isotope forward model from in situ hydrologic observations and satellite water vapor isotope measurements. A control simulation of snow δ18O captures the mean and seasonal trend but underestimates the observed intraseasonal variability. The simulation of observed variability is improved by including amount effects associated with South American cold air incursions, linking synoptic-scale disturbances and monsoon dynamics to tropical ice core δ18O. The forward model was calibrated with and run under present-day conditions but can also be driven with past climate forcings to reconstruct paleomonsoon variability. The model is transferable and may be used to render a (paleo)climatic context at other ice core locations.

  3. A new minute Andean Pristimantis (Anura: Strabomantidae from Venezuela

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    César L. Barrio-Amorós


    Full Text Available A new species of Pristimantis is described from the Venezuelan Andes. The new species is the smallest in its genus known in Venezuela and belongs to the Pristimantis unistrigatus Group. It differs from the rest of Venezuelan Andean congeners in body size (mean male SVL < 21.3 mm, female SVL < 26.3 mm, expanded discs on fingers and toes, absence of dorsolateral folds, and a distinctivecall consisting in 2–5 cricket-like short notes. The new species inhabits the southwestern part of the Cordillera de Mérida in Venezuela and the Venezuelan side of the Cordillera Oriental deColombia, and could be present on the Colombian portion of the cordillera as well.

  4. An Outbreak of Bartonella bacilliformis in an Endemic Andean Community.

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    Nuria Sanchez Clemente

    Full Text Available Bartonellosis affects small Andean communities in Peru, Colombia and Ecuador. Research in this area has been limited.Retrospective review of 191 cases of bartonellosis managed in Caraz District Hospital, Peru, during the last outbreak (2003.The majority of cases (65% were 14 years old and younger. There was a peak in acute cases after the rainy season; chronic cases presented more constantly throughout the year. The sensitivity of blood smear against blood culture in acute disease was 25%. The most commonly used treatment for chronic disease was rifampicin; chloramphenicol was used to treat most acute cases. Complications arose in 6.8% and there were no deaths.Diagnostic and treatment algorithms for acute and chronic bartonellosis have been developed without a strong evidence base. Preparation of ready-to-go operational research protocols for future outbreaks would strengthen the evidence base for diagnostic and treatment strategies and enhance opportunities for control.

  5. Climate Change Impacts in a Colombian Andean Tropical Basin (United States)

    Ocampo, O. L.; Vélez, J. J.; Londoño, A.


    Climate change and climate variability have a large impact on water resources. Developing regions have less capacity to prepare for, respond to, and recover from climate-related hazards and effects, and then, populations may be disproportionately affected. In Colombia, the geographical location and the marked irregularity in the terrain, give as a result, a complex climate. These factors have contributed to the water supply of the territory. Unfortunately, the visualization of abundant and inexhaustible water resources created a great disregard for them. Besides, the water supply is not distributed uniformly across the country, and then there is water-deficit in some areas as Andean Region, where the largest population and the main development centers are located. In recent decades, water conflicts have emerged locally and regionally, which have generated a crisis in the allocation mechanisms and have improved the understanding of the water situation in Colombia. The Second National Communication to CCMNU alerts on possible future consequences of climate change and the need for regional studies for understanding climate change impacts on the fragile ecosystems of high mountains as paramos and fog forest, which are water production regulators. Colombian water resources are greatly affected by changes in rainfall patterns influenced by El Niño and La Niña. The recent disasters in the 2010-2011 rainy seasons have caught the attention of not only the authorities but from the scientific community to explore strategies to improve water management by tracking, anticipating and responding to climate variability and climate change. Whereas sound water management is built upon long-term, the country is undertaking a pilot exercise for the integrated management of water resources, five Basins are selected, among them, is the Chinchiná River Basin; this Andean tropical Basin is located on the western slopes at the central range in the Andes between 4°48 and 5°12 N

  6. Spatial random downscaling of rainfall signals in Andean heterogeneous terrain (United States)

    Posadas, A.; Duffaut Espinosa, L. A.; Yarlequé, C.; Carbajal, M.; Heidinger, H.; Carvalho, L.; Jones, C.; Quiroz, R.


    Remotely sensed data are often used as proxies for indirect precipitation measures over data-scarce and complex-terrain areas such as the Peruvian Andes. Although this information might be appropriate for some research requirements, the extent at which local sites could be related to such information is very limited because of the resolution of the available satellite data. Downscaling techniques are used to bridge the gap between what climate modelers (global and regional) are able to provide and what decision-makers require (local). Precipitation downscaling improves the poor local representation of satellite data and helps end-users acquire more accurate estimates of water availability. Thus, a multifractal downscaling technique complemented by a heterogeneity filter was applied to TRMM (Tropical Rainfall Measuring Mission) 3B42 gridded data (spatial resolution ~ 28 km) from the Peruvian Andean high plateau or Altiplano to generate downscaled rainfall fields that are relevant at an agricultural scale (spatial resolution ~ 1 km).

  7. A new Andean species of Philodryas (Dipsadidae, Xenodontinae) from Ecuador. (United States)

    Zaher, Hussam; Arredondo, Juan C; Valencia, Jorge H; Arbeláez, Ernesto; Rodrigues, Miguel T; Altamirano-Benavides, Marco


    We describe a new species of Philodryas from the highlands of southern Ecuador. The new species is distinguished from all known species of Philodryas by a unique combination of coloration, scalation, and hemipenial characters. The new species resembles Philodryas simonsii in color pattern. However, they differ notoriously by their hemipenial morphology. The three other trans-Andean members of the genus (Philodryas simonsii, Philodryas chamissonis, and Philodryas tachymenoides), along with the new species, compose a probably monophyletic group that may be characterized by the presence of ungrooved postdiastemal teeth in the maxilla. Unlike most species of the genus Philodryas, the new species shows a restricted distribution, being apparently endemic to a small region of high-altitude (3150-4450m) grasslands in the southern Andes of Ecuador.

  8. Genetic diversity of Phytophthora infestans in the Northern Andean region

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    Grünwald Niklaus J


    Full Text Available Abstract Background Phytophthora infestans (Mont. de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana and tree tomato (Solanum betaceum, all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a and one mitochondrial (Cox1 region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Results Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. Conclusions The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

  9. Central Andean crustal structure from receiver function analysis (United States)

    Ryan, Jamie; Beck, Susan; Zandt, George; Wagner, Lara; Minaya, Estela; Tavera, Hernado


    The Central Andean Plateau (15°-27°S) is a high plateau in excess of 3 km elevation, associated with thickened crust along the western edge of the South America plate, in the convergent margin between the subducting Nazca plate and the Brazilian craton. We have calculated receiver functions using seismic data from a recent portable deployment of broadband seismometers in the Bolivian orocline (12°-21°S) region and combined them with waveforms from 38 other stations in the region to investigate crustal thickness and crust and mantle structures. Results from the receiver functions provide a more detailed map of crustal thickness than previously existed, and highlight mid-crustal features that match well with prior studies. The active volcanic arc and Altiplano have thick crust with Moho depths increasing from the central Altiplano (65 km) to the northern Altiplano (75 km). The Eastern Cordillera shows large along strike variations in crustal thickness. Along a densely sampled SW-NE profile through the Bolivian orocline there is a small region of thin crust beneath the high peaks of the Cordillera Real where the average elevations are near 4 km, and the Moho depth varies from 55 to 60 km, implying the crust is undercompensated by 5 km. In comparison, a broader region of high elevations in the Eastern Cordillera to the southeast near 20°S has a deeper Moho at 65-70 km and appears close to isostatic equilibrium at the Moho. Assuming the modern-day pattern of high precipitation on the flanks of the Andean plateau has existed since the late Miocene, we suggest that climate induced exhumation can explain some of the variations in present day crustal structure across the Bolivian orocline. We also suggest that south of the orocline at 20°S, the thicker and isostatically compensated crust is due to the absence of erosional exhumation and the occurrence of lithospheric delamination.

  10. [Elaboration and evaluation of infant food based on Andean crops]. (United States)

    Repo-Carrasco, R; Hoyos, N L


    The Andes mountain range of South America is one of the most important centres for crop domestication, potato, corn, and lesser known grains such as quinua, cañihua, kiwicha and tarwi are indigenous of these highlands. These Andean grains have adapted perfectly to the climatic and geographical conditions present, whereas other grains have not been able to survive. In addition to their hardiness, they also have a high nutritional value. Bearing in mind on one hand, the high nutritional value of these indegenous products, and on the other hand the high rate of child malnutrition prevalent in the population, it was considered important to look for new variations in their processing which would facilitate their consumption by the poor working classes, especially the children. Accordingly three different flour mixtures were developed based on these Andean grains, the mixtures were then subjected to bromatological and biological analysis. The three new flour mixtures were: Quinua-Cañihua-Broad Bean (Q-C-B), Quinua-Kiwicha-Bean (Q-K-B) and Kiwicha-Rice (K-R). The protein content of these mixtures varied between 11.35-15.46 g/100g, the mixture K-R having the lowest protein level and the Q-C-B having the highest. The Q-K-B mixture had the highest chemical score, PER and NPU value. This PER value of 2.59 was higher than the value of casein which was 2.50. In addition this mixture had a chemical score of 0.94 and a NPU value of 59.38. The Q-C-B mixture had a chemical score of 0.88 and its PER, NPU and Digestibility values were 2.36, 47.24 and 79.2 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. 78 FR 21002 - Andean Trade Preference Act (ATPA), as Amended: Request for Public Comments Regarding Beneficiary... (United States)


    ... From the Federal Register Online via the Government Publishing Office TRADE REPRESENTATIVE Andean.... The original ATPA allowed Bolivia, Ecuador, Colombia, and Peru to be considered as beneficiary... November 25, 2008, the President determined that Bolivia no longer satisfied the eligibility...

  12. 杂多地区喜山期花岗斑岩地球化学特征及地质意义%Geochemistry Characteristics and Geological Significance of the Himalayan Period Granit-Porphyry in the Zaduo Region

    Institute of Scientific and Technical Information of China (English)

    付军; 保广普; 刘春娥; 王永文; 李建放; 马延景


    杂多地区花岗斑岩的麦多拉和纳日贡玛等岩体,测年结果显示年龄值分布为(40.8士0.4)Ma、(43.3士0.5)Ma,为喜山期的产物,杂多地区岩体是同一时代的产物.杂多地区多金属成矿带,包括纳日贡玛—麦多拉—乌葱察别—迪拉亿—哼赛青等斑岩型铜、铅、锌、钼、金、银等多金属矿床,微量元素(包括稀土元素),研究结果表明含矿斑岩和共生的钾质斑岩岩体在时空上具一致性,岩石化学成分均富碱(w(K2O)+w(Na2O)>5%),高K和w (K2O)/w(Na2O)值远大于1, 微量元素富集Sr、Ba等大离子亲石元素和轻稀土元素等,均显示出钾玄岩和高钾系列岩石的特征,暗示杂多地区多金属成矿带的含矿斑岩属于典型的钾玄岩和高钾系列的斑岩.%The age of Maiduola granit-porphyry and Narigongma lithsomes, is the value of (40. 86±0. 4) Ma, (43. 3±0. 5) Ma. and they are the product of the early Stage of Yanshan, through the LAICP-M S zircon U-Pb isotopic dating, which indicate that many parts of the complex product of the times is the same lithsomes, the multi-metallic deposits of Cu, Mo, Pb, Zn, Au and Ag etc. of the porphyry types and trace elements (include REE) are found from narigongma, maiduola, yucongeongchabie, dilayi and hengsaiqing copper ore belt in the Eastern Tibet. The analytical results show that the ore-bearing porphyry and coexisting potassic plutons rocks, volcanic rocks and plutons have the same temporal-spatial distribution, uniform in the petrochemical compositions with alkali-rich (a; (K2O+NazO) >5%), high potassium and w (KZO) /w (Na2O) >1, and a strong enrichment in LILE of Sr, Ba etc and LREE. This shows the characteristics of the shoshonitic series rocks, indicating the ore-bearing porphyry of the

  13. Re-Os and U-Pb geochronology of the Laochang Pb-Zn-Ag and concealed porphyry Mo mineralization along the Changning-Menglian suture, SW China: implications for ore genesis and porphyry Cu-Mo exploration (United States)

    Deng, Xiao-Dong; Li, Jian-Wei; Zhao, Xin-Fu; Wang, Hong-Qiang; Qi, Liang


    Numerous polymetallic volcanogenic massive sulfide (VMS), vein, and replacement deposits are distributed along the Changning-Menglian suture zone in Sanjiang Tethyan metallogenic province, SW China. Laochang is the largest Pb-Zn-Ag vein and replacement deposit in this area, with a proven reserve of 0.51 Mt Pb, 0.34 Mt Zn, and 1,737 t Ag. Its age and relationship to magmatic events and VMS deposits in the region, however, have long been debated. In this paper, we present pyrite Re-Os and titanite U-Pb ages aiming to provide significant insights into the timing and genesis of the Pb-Zn-Ag mineralization. Pyrite grains in textural equilibrium with galena, sphalerite, and chalcopyrite from stratabound Pb-Zn-Ag and Cu-bearing Pb-Zn-Ag orebodies have a Re-Os isochron age of 45.7 ± 3.1 Ma (2 σ, mean square weighted deviation (MSWD) = 0.45), whereas titanite grains intergrown with sulfide minerals yield a weighted mean 206Pb/238U age of 43.4 ± 1.2 Ma (2 σ, n = 8). A Mo-mineralized granitic porphyry intersected by recent drilling below the Laochang Pb-Zn-Ag ores yields a zircon U-Pb age of 44.4 ± 0.4 Ma (2 σ, n = 12). Within analytical uncertainties, the ages of the Pb-Zn-Ag deposit and the concealed Mo-mineralized porphyry are indistinguishable, indicating that they are products of a single magmatic hydrothermal system. The results show that Laochang Pb-Zn-Ag deposit is significantly younger than the host mafic volcanic rock (zircon U-Pb age of 320.8 ± 2.7 Ma; 2 σ, n = 12) and Silurian VMS deposits along the Changning-Menglian suture zone, arguing against its origin as a Carboniferous VMS deposit as many researchers claimed. The initial 187Os/188Os ratio (0.540 ± 0.012) obtained from the pyrite Re-Os isochron suggests that metals were likely derived from the granitic porphyry that formed from a hybrid magma due to mixing of crustal- and mantle-derived melts, rather than from the mafic volcanic host rocks as previously thought. Our results favor that the Laochang

  14. 蒙西斑岩铜钼矿含矿岩体地球化学和Sr-Nd-Pb同位素特征%Geochemical and Sr-Nd-Pb Isotopic Characteristics of the Ore-bearing Rock in Mengxi Porphyry Cu-Mo Deposit

    Institute of Scientific and Technical Information of China (English)

    刘建朝; 王瑞美; 程建新; 彭素霞; 张海东; 王得权; 郑利宏


    Ore-bearing porphyry in Mengxi porphyry Copper-Molybdenum deposit is plagiogranite porphyry.The geo-chemical and Sr-Nd-Pb isotope research of porphyry bodies show that rocks are peraluminous calc-alkaline,enriched in large-ion lithophile elements Rb,Ba,U,K,Pb,Sr and depleted in high field strength elements Th,Ta,Nb,Nd,Ti.Through the studies on porphyry bodies,it is identified for rock bodies characterized with low (87Sr/86Sr) ⅰ ratio (0.7046 5~0.7053 7) and high εNd(t) value (-2.2~6.6).(206Pb/204Pb)i ratio of the rock bodies range from 17.13 to 17.33,(207Pb/204Pb)i ratio from 15.47 to 15.54,and (208Pb/204Pb)i ratio from 37.11 to 37.33.These characteristics indicate that the porphyry bodies possibly formed in arc environment, and the magmatic materials were derived from the mantle,involved some portions of crustal rocks,which may related with partial melting of subducted oceanic crust.Qiongheba in eastern Junggar is a potential area for prospecting the phyry Cu deposit.%蒙西斑岩铜钼矿含矿斑岩体主要为斜长花岗斑岩。通过对含矿斑岩体地球化学和Sr-Nd-Pb同位素特征的研究,确立斑岩体为过铝质钙碱性系列岩石,富集Rb,Ba,U,K,Pb,Sr等大离子亲石元素,亏损Th,Ta,Nb,Nd,Ti等高场强元素;具低的(87Sr/86Sr)ⅰ值(0.70465~0.70537)和相对较高的εNd(t)值(-2.2~6.6),且有较低的初始铅同位素比值(206Pb/204Pb)i=17.13~17.33,(207Pb/204Pb)i=15.47~15.54,(208Pb/204Pb)i=37.11~37.33。上述特征表明其形成于岛弧环境,岩浆物质来源以幔源为主,但也有少量壳源组分参与,岩浆的形成可能与洋壳的俯冲作用有关。东准噶尔琼河坝地区是形成和寻找斑岩型铜矿的有利地区。

  15. Pressure gradients and boiling as mechanisms for localizing ore in porphyry systems (United States)

    Cunningham, Charles G.


    Fluid inclusions in ore zones of porphyry systems indicate that extensive boiling of hydrothermal fluids accompanies deposition of ore and gangue minerals. The boiling commonly accompanied a change from a lithostatic to a hydrostatic environment during evolution of an epizonal stock. Pressure gradients near the margin of the stock can determine whether ore or only a diffuse zone of mineralization is formed. A sharp drop in pressure in an epizonal environment is more likely to cause extensive boiling than a comparable change in a deeper environment, as the slope of the boiling curve steepens with an increase 'in pressure. The drop in pressure causes the hydrothermal fluids to boil and creates a crackle (stockwork) breccia, which hosts the veinlets of gangue quartz and ore minerals. The boiling selectively partitions CO2, H2S, and HCl into the vapor phase, changing the pH, composition, ionic strength, and thus the solubility product of metal complexes in the remaining liquid and causing the ore and gangue to come out of solution. Fluid inclusions trapped from boiling solutions can exhibit several forms, depending on the physical and chemical conditions of the hydrothermal fluid from which they were trapped. In one case, inclusions when heated can homogenize to either liquid or vapor at the same temperature, which is the true boiling temperature. In another case, homogenization of various inclusions can occur through a range of temperatures. The latter case results from the trapping of mixture of liquid and vapor. Variations in salinity can result from boiling of the hydrothermal fluid, or intermittent incorporation of high-salinity fluids from the magma, or trapping of fluids of varying densities at pressure-temperature conditions above the critical point of the fluid. In places, paleopressure-temperature transition zones can be recognized by fluid-inclusion homogenization temperatures and phase relationships and by the presence of anhydrite daughter minerals

  16. The formation of Luoboling porphyry Cu-Mo deposit: Constraints from zircon and apatite (United States)

    Li, Cong-ying; Hao, Xi-luo; Liu, Ji-qiang; Ling, Ming-xing; Ding, Xing; Zhang, Hong; Sun, Wei-dong


    The Luobuling porphyry Cu-Mo deposit belongs to the Late Cretaceous Zijinshan Cu-Au-Mo mineralization field in southeastern China. Due to intensive hydrothermal alteration and weathering, it is very difficult to collect fresh whole rock samples for geochemical and isotopic studies in Luobuling. Zircon and apatite are accessory minerals that are resistant to hydrothermal alterations. In this study, we compared the trace element and isotope compositions of zircon and apatite from ore-bearing and barren samples to understand the formation of the Luoboling Cu-Mo deposit. Zircon U-Pb LA-ICP-MS dating shows that the Luoboling porphyries formed at 100 Ma (100.3 ± 1.2 Ma, 100.6 ± 1.5 Ma and 98.6 ± 1.2 Ma), which belongs to the late stage mineralization of the Zijinshan mineralization field. Zhongliao porphyritic granodiorite has the same age as the deposit (99.5 ± 1.6 Ma). The age of barren Sifang granodiorite is slightly older (109.7 ± 0.8 Ma). All these zircon grains have high Ce4+/Ce3+ ratios, indicating high oxygen fugacities. The ore-bearing samples show variable εHf(t) of - 7.3 to 0.2, suggesting either heterogeneous sources or mixing of two different magmas. Interestingly, the Hf isotope composition of barren samples is systematically higher (εHf(t) of - 3.6 to 5.5), implying a lower contribution of crustal materials. The OH mole percent of apatite grains from barren samples (LBL22-03 and SF09-05) is 0.5, which is higher than that of apatite from the ore-bearing samples (LBL20-01 LBL20-02 and LBL22-02), indicating lower F, Cl contents or higher water contents in the magma. In apatite from the ore-bearing samples, Sr is high, indicating the absence of plagioclase crystallization. In contrast, barren samples have varied and lower Sr, indicating that apatite crystallization was accompanied by plagioclase. These patterns were controlled by water contents because the crystallization of plagioclase is suppressed by high water contents in magmas. It also suggests

  17. On the Yangtze—type Copper Deposits and Their Polygentic Origin

    Institute of Scientific and Technical Information of China (English)



    The so-called“Yangtze-type”copper deposits include:(1)Cu-bearing massive pyrite bed ,(2)Cu-bearing skarn and magnetite-type ore deposits,with replacement Cu-vein-type deposits near the metasomatic zone,and (3)mineralized intrusive bodies and breccia pipes ,some of which are known as porphyry copper ores(e.g.Chengmenshan).This type of ore deposits is a typical example to verify the polygenesis of inost of the deposits in China,as has been promoted by Prof.Tu Guangchi in view of the polycyclic development of the geological history in China.This paper is con-cemed with one sub-type of such deposits.

  18. Special Xenoliths in an Aegirine--Augite Syenite Porphyry in Liuhe, Yunnan, China: Discovery and Implications

    Institute of Scientific and Technical Information of China (English)

    LIU Xianfan; SONG Xiangfeng; LU Qiuxia; TAO Zhuan; LONG Xunrong; ZHAO Fufeng


    Three special types of xenoliths have recently been found in an aegirine-augite syenite porphyry in Liuhe, Yunnan, China. Petrographical, petrochemical, electron microprobe, and scanning electron microscopy studies indicate that pure calcite xenocrysts and quartz-bearing topaz pegmatite xenoliths result from the degassing of mantle fluids during their migration, and that black microcrystalline iron-rich silicate-melt xenoliths are the product of the extraction of mantle fluids accompanying degassing and are composed dominantly of quartz, chlorite, and iron-rich columnar and sheet silicate minerals with characteristic minerals, such as native iron, apatite, and zircon. According to the bulk-rock chemical and mineral compositions and crystallization states, the microcrystalline melt xenoliths are not the product of conventional magmatism, and especially the existence of native iron further proves that the xenoliths were mantle fluid materials under reduction or anoxic conditions. The study of the special xenoliths furnishes an important deep-process geochemical background of polymetalUc mineralization in different rocks and strata in the study area.

  19. Changing Hydrology in Glacier-fed High Altitude Andean Peatbogs (United States)

    Slayback, D. A.; Yager, K.; Baraer, M.; Mohr, K. I.; Argollo, J.; Wigmore, O.; Meneses, R. I.; Mark, B. G.


    Montane peatbogs in the glacierized Andean highlands of Peru and Bolivia provide critical forage for camelids (llama and alpaca) in regionally extensive pastoral agriculture systems. During the long dry season, these wetlands often provide the only available green forage. A key question for the future of these peatbog systems, and the livelihoods they support, is the impact of climate change and glacier recession on their hydrology, and thus forage production. We have already documented substantial regional glacier recession, of, on average, approximately 30% of surface area over the past two decades. As glaciers begin to retreat under climate change, there is initially a period of increased meltwater outflow, culminating in a period of "peak water", and followed by a continual decline in outflows. Based on previous work, we know that some glaciers in the region have already passed peak water conditions, and are now declining. To better understand the impacts of these processes on peatbog hydrology and productivity, we have begun collecting a variety of surface data at several study sites in both Bolivia and Peru. These include precipitation, stream flow, water levels, water chemistry and isotope analyses, and peatbog biodiversity and biomass. These measurements will be used in conjunction with a regional model driven by satellite data to predict likely future impacts. We will present the results from these initial surface measurements, and an overview of satellite datasets to be used in the regional model.

  20. Mechanisms of O2 transport in Andean dogs. (United States)

    Banchero, N; Cruz, J; Bustinza, J


    Using previously inserted catheters, 11 dogs native to high altitude (7.5-23 kg bwt) were studied standing and unsedated in Cerro de Pasco, Peru at 4350 meters. Hemoglobin (Hb), hematocrit (Hct), O2 and CO2 contents, PO2, PCO2 and pH were measured in simultaneously obtained arterial and mixed venous blood samples. Blood pressures were measured in the pulmonary artery and the left ventricle and cardiac output (Q) was determined by dye dilution. Moderately higher values for Hb and Hct were found in these dogs. Hb-O2 affinity was no different than that found in sea level dogs: the P50 in the Andean dogs was 31.6 mm Hg at 38 degrees C and pH of 7.4. Because of the low barometric pressure at 4350 m (458 mmHg) the partial pressures of oxygen in inspired and in alveolar air were lower than at sea level: 84.3 and 56.4 mm Hg, respectively. PAO2 and PVO2, were 55.5 and 32.9 mm Hg while the SAO2 and SVO2 were 79.5 and 50.7%, respectively. Marked hyperventilation was observed (PACO2, 25.6 mm Hg) however, pH was normal. Cardiac output was normal (average 162 plus or minus 39 ml/min/kg). Moderate pulmonary arterial hypertension was observed in the presence of normal left ventricular end diastolic pressure suggesting increased pulmonary vascular resistance.

  1. Cerebral vasoreactivity in Andeans and headache at sea level. (United States)

    Appenzeller, O; Passino, C; Roach, R; Gamboa, J; Gamboa, A; Bernardi, L; Bonfichi, M; Malcovati, L


    Headache is common in Cerro de Pasco (CP), Peru (altitude 4338 m) and was present in all patients with chronic mountain sickness (CMS) in CP reported here. Forty-seven percent of inhabitants report headache. Twenty-four percent of men have migraine with aura, with an average of 65 attacks a year. We assessed vasoreactivity of the cerebral vessels to CO2 by rebreathing and to NO by the administration of isosorbite dinitrate (IDN), a nitric oxide (NO) donor, using transcranial Doppler ultrasound in the middle cerebral artery (MCA) in natives of CP, some of whom suffered from CMS. We repeated the measurements in Lima (altitude 150 m) in the same subjects within 24 h of arrival. Vasodilatation in the middle cerebral artery supply territory in response to CO2 and NO, both physiologic vasodilators, is defective in Andean natives at altitude and in the same subjects at sea level. Incapacitating migraine can occur with impaired cerebral vasoreactivity to physiologic vasodilators. We propose that susceptibility to migraine might depend in part on gene expression with consequent alterations of endothelial function.

  2. Andean subduction orogeny: feedbacks between tectonics, relief evolution and global climate (United States)

    Lacassin, Robin; Armijo, Rolando; Coudurier-Curveur, Aurélie; Carrizo, Daniel


    The Andean subduction margin, largest tectonic relief on the Earth (13 km vertically from the trench to the Altiplano) has a stepped morphology, which results of the evolution over the past 50 Myr of two parallel flat-ramp thrust systems, at the - previously unidentified - West Andean Thrust (WAT), and at the subduction interface. The evolution of those thrusts appears concomitant with increasing aridity in the Atacama Desert, which keeps a large-scale record of interplaying tectonics and Cenozoic climate change. The coastal morphology is dominated by the Atacama Bench, a giant uplifted terrace at 1-2km asl. Geomorphic and climatic data, numerical experiments of drainage formation are consistent with the development of a flat Atacama morphology close to sea level, interrupted at ≤10 Ma by tectonic uplift prevailing to the present. This suggests recent trench-ward relief growth by incorporation of the coastal Atacama Bench to the Andes reliefs. Thrust splay structures and other complexities above the subduction interface may explain this relief growth, as well as the distribution of asperities under the oceanward forearc, and the down-dip segmentation of coupling and seismicity on the megathrust. Combining those results with geological knowledge at the scale of the whole Central Andes, we show that the Andean orogeny results from protracted processes of bivergent crustal shortening in a wide region squeezed between the rigid Marginal Block and the S America Plate. The overall growth curve of Andean orogeny over the past 50 Myr appears synchronous with the onset of the "ramp-shaped" temperature decrease since the Early Eocene climatic optimum. Andean growth and global cooling may have operated under the same forcing mechanism at plate-scale, involving viscous flow in the mantle. But Andean growth appears modulated by climatic feedbacks causative of stepwise reductions of erosive power over the Andean margin. The first of such events is coeval with Late Eocene

  3. Estimating detection and density of the Andean cat in the high Andes (United States)

    Reppucci, Juan; Gardner, Beth; Lucherini, Mauro


    The Andean cat (Leopardus jacobita) is one of the most endangered, yet least known, felids. Although the Andean cat is considered at risk of extinction, rigorous quantitative population studies are lacking. Because physical observations of the Andean cat are difficult to make in the wild, we used a camera-trapping array to photo-capture individuals. The survey was conducted in northwestern Argentina at an elevation of approximately 4,200 m during October–December 2006 and April–June 2007. In each year we deployed 22 pairs of camera traps, which were strategically placed. To estimate detection probability and density we applied models for spatial capture–recapture using a Bayesian framework. Estimated densities were 0.07 and 0.12 individual/km2 for 2006 and 2007, respectively. Mean baseline detection probability was estimated at 0.07. By comparison, densities of the Pampas cat (Leopardus colocolo), another poorly known felid that shares its habitat with the Andean cat, were estimated at 0.74–0.79 individual/km2 in the same study area for 2006 and 2007, and its detection probability was estimated at 0.02. Despite having greater detectability, the Andean cat is rarer in the study region than the Pampas cat. Properly accounting for the detection probability is important in making reliable estimates of density, a key parameter in conservation and management decisions for any species.

  4. Geologic and geochemical insights into the formation of the Taiyangshan porphyry copper–molybdenum deposit, Western Qinling Orogenic Belt, China (United States)

    Kun-Feng Qiu,; Taylor, Ryan D.; Yao-Hui Song,; Hao-Cheng Yu,; Kai-Rui Song,; Nan Li,


    Taiyangshan is a poorly studied copper–molybdenum deposit located in the Triassic Western Qinling collisional belt of northwest China. The intrusions exposed in the vicinity of the Taiyangshan deposit record episodic magmatism over 20–30 million years. Pre-mineralization quartz diorite porphyries, which host some of the deposit, were emplaced at 226.6 ± 6.2 Ma. Syn-collisional monzonite and quartz monzonite porphyries, which also host mineralization, were emplaced at 218.0 ± 6.1 Ma and 215.0 ± 5.8 Ma, respectively. Mineralization occurred during the transition from a syn-collisional to a post-collisional setting at ca. 208 Ma. A barren post-mineralization granite porphyry marked the end of post-collisional magmatism at 200.7 ± 5.1 Ma. The ore-bearing monzonite and quartz monzonite porphyries have a εHf(t) range from − 2.0 to + 12.5, which is much more variable than that of the slightly older quartz diorite porphyries, with TDM2 of 1.15–1.23 Ga corresponding to the positive εHf(t) values and TDM1 of 0.62–0.90 Ga corresponding to the negative εHf(t) values. Molybdenite in the Taiyangshan deposit with 27.70 to 38.43 ppm Re suggests metal sourced from a mantle–crust mixture or from mafic and ultramafic rocks in the lower crust. The δ34S values obtained for pyrite, chalcopyrite, and molybdenite from the deposit range from + 1.3‰ to + 4.0‰, + 0.2‰ to + 1.1‰, and + 5.3‰ to + 5.9‰, respectively, suggesting a magmatic source for the sulfur. Calculated δ18Ofluid values for magmatic K-feldspar from porphyries (+ 13.3‰), hydrothermal K-feldspar from stockwork veins related to potassic alteration (+ 11.6‰), and hydrothermal sericite from quartz–pyrite veins (+ 8.6 to + 10.6‰) indicate the Taiyangshan deposit formed dominantly from magmatic water. Hydrogen isotope values for hydrothermal sericite ranging from − 85 to − 50‰ may indicate that magma degassing progressively depleted residual liquid in

  5. Re-Os isotopic and trace element compositions of pyrite and origin of the Cretaceous Jinchang porphyry Cu-Au deposit, Heilongjiang Province, NE China (United States)

    Zhang, Peng; Huang, Xiao-Wen; Cui, Bin; Wang, Bo-Chao; Yin, Yi-Fan; Wang, Jing-Rui


    The Jinchang Cu-Au deposit in Northeast China contains more than 76 tons of Au and 4683 tons of Cu with average ore grades of 11.34 g/t Au and 1.44% Cu. The deposit is typical of porphyry types and consists of gold orebodies mainly hosted in a ∼113 Ma granitic porphyry and breccia pipes within the porphyry intrusion. Mineralization is closely associated with early potassic alteration and late phyllic alteration. Pyrite is the main Au-bearing mineral and contains 1.48-18.9 ppb Re and 11.4-38 ppt common Os. Extremely low common Os concentrations and high Re/Os ratios are indicative of derivation of ore-forming materials from the crust. Low Re in pyrite from the Jinchang deposit may indicate a mixing source of mantle and crust or a crustal source. Five Re-Os isotopic analyses yield a model 1 isochron age of 114 ± 22 Ma (2σ, MSWD = 0.15), similar to the age of the host porphyry. Pyrite contains detectable Co, Ni, Cu, Zn, As, Ag, Au, Sb, Pb and Bi. Pyrite has Co/Ni ratios similar to that of volcanogenic and hydrothermal sulfide deposits, indicating a magmatic-hydrothermal origin, and has Au and As contents similar to that of porphyry-epithermal systems. Pyrite grains from potassic and phyllic alteration stages have different trace element contents, reflecting the evolution of ore-forming fluids from magmatic dominated to magmatic mixed with meteoric water. In combination with regional geology, our new results are suggestive of origin of the Jinchang Cu-Au deposit from contemporary intrusions of granitic porphyries related to the Early Cretaceous subduction of the Paleo-Pacific plate.

  6. Exploring the potential of an Andean fruit: an interdisciplinary study on the cape gooseberry (Physalis peruviana L.) value chain

    NARCIS (Netherlands)

    Olivares Tenorio, Mary Luz


    Cape gooseberry is a fruit cultivated in Andean countries. Currently it is available some international markets, besides the domestic Andean market. Colombia is the major producer and export country at the moment. The value chain of cape gooseberry faces several barriers of technological and governa

  7. Brain blood flow in Andean and Himalayan high-altitude populations: evidence of different traits for the same environmental constraint

    NARCIS (Netherlands)

    G.F.A. Jansen; B. Basnyat


    Humans have populated the Tibetan plateau much longer than the Andean Altiplano. It is thought that the difference in length of occupation of these altitudes has led to different responses to the stress of hypoxia. As such, Andean populations have higher hematocrit levels than Himalayans. In contras

  8. Transference of some microsatellite molecular markers from Fabaceae family to Andean Lupin (Lupinus mutabilis Sweet

    Directory of Open Access Journals (Sweden)

    Michelle C. Chirinos-Arias


    Full Text Available In order to analyze transferibility of 15 microsatellite primers from Fabaceae family to Lupinus mutabilis Sweet "andean lupine" chosen to present transferability between species and genera, by its high rate of polymorphic content (PIC and high degree of observed and expected heterozygosity. DNA was extracted of 300 andean lupines plants, PCR conditions were standardized by gradients of master mix components. Primers for screening were run on 3% agarose gel with some samples. Finally population was amplified and run on 6% polyacrylamide gel for its highest resolution. Only 6.67% of primers were amplified, but they were monomorphic, so they cannot be used for molecular characterization. We proposed eight microsatellite primers for andean lupin wich should be probed in laboratory conditions.

  9. How widely is the Andean type of continental margin represented in the Archean (United States)

    Burke, Kevin


    Application of the principle of uniformitarianism to the Archean was discussed in a search for evidence of Archean-type continental margins in Archean rocks. The author cautioned that Archean rocks represent only 2 percent of the current exposure of the continents, half of which is in the North American Superior Province. Care must be taken in interpreting the global tectonic significance of relatively small exposures of Archean rocks, such as South India. Andean margins were characterized by their elongate shape, magmatic associations, and isotopic signatures. Although the compositional evidence alone will always be ambiguous, it was suggested that supporting structural evidence may aid in the identification of Archean Andean margins. Andean margin remains have been recognized in the Superior Province of Canada by these criteria, and the author suggested that the Closepet granite of South India may represent another example.

  10. Diverging responses of tropical Andean biomes under future climate conditions. (United States)

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter


    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%-17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for other

  11. Diverging Responses of Tropical Andean Biomes under Future Climate Conditions (United States)

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter


    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%–17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for

  12. Copper Products Capacity Expansion Stimulate the Copper Consumption

    Institute of Scientific and Technical Information of China (English)


    <正>The dramatic growth of copper consumption in China can directly be seen from the expansion of copper products capacity.According to sta- tistics,in the past 4 years,the improvement on the balance of trade on copper bar,copper,and copper alloy and copper wire & cable has driven the growth of copper consumption a lot.

  13. Chromosome identification in the Andean common bean accession G19833 (Phaseolus vulgaris L., Fabaceae

    Directory of Open Access Journals (Sweden)

    Sarah Altrock


    Full Text Available Characterization of all chromosomes of the Andean G19833 bean genotype was carried out by fluorescent in situ hybridization. Eleven single-copy genomic sequences, one for each chromosome, two BACs containing subtelomeric and pericentromeric repeats and the 5S and 45S ribosomal DNA (rDNA were used as probes. Comparison to the Mesoamerican accession BAT93 showed little divergence, except for additional 45S rDNA sites in four chromosome pairs. Altogether, the results indicated a relative karyotypic stability during the evolution of the Andean and Mesoamerican gene pools of P. vulgaris.

  14. Diversity and ecological ranges of plant species from dry inter-Andean valleys

    DEFF Research Database (Denmark)

    Quintana, Catalina

    of Ecuadorian dry inter-Andean valleys vegetation, including information related to the physical settings as well as to the vegetation and flora of the valleys. 2) This chapter unveils the influence of disturbance, water availability and low temperature in shaping species composition and occurrence. We found...... found on steep slopes and in ravines. These areas of original dry valley vegetation preserve many wild relatives of cultivated plants on the one hand and old lineages of other wild plant groups. Dry inter-Andean valleys (DIAVs) in Ecuador therefore makeup a biodiversity hot spot for both plants...

  15. Antwerp Copper Plates

    DEFF Research Database (Denmark)

    Wadum, Jørgen


    In addition to presenting a short history of copper paintings, topics detail artists’ materials and techniques, as well as aspects of the copper industry, including mining, preparation and trade routes.......In addition to presenting a short history of copper paintings, topics detail artists’ materials and techniques, as well as aspects of the copper industry, including mining, preparation and trade routes....

  16. Copper and copper proteins in Parkinson's disease. (United States)

    Montes, Sergio; Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo


    Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology.

  17. Sequence-modified primers for the differential RT-PCR detection of Andean potato latent and Andean potato mild mosaic viruses in quarantine tests. (United States)

    Koenig, Renate; Ziebell, Heiko


    To enable the differential PCR detection of Andean potato latent virus (APLV) and Andean potato mild mosaic virus (APMMV) strains, sense primers were designed that correspond to regions directly upstream of the coat protein genes. Their differentiating power was increased by A->C or T->C replacements in their 3'-terminal parts. Together with the broad-specificity antisense primer EM3, primer AL-a-mod3C detected all APLV strains tested, but none of the APMMV strains. Primer AM-a-mod4C yielded PCR products with all APMMV preparations, but also with some APLV preparations. Sequence analysis revealed that this was not due to a lack of primer specificity, but to the sensitive detection of contaminating APMMV in some of our APLV preparations.

  18. The transition from porphyry- to epithermal-style gold mineralization at Ladolam, Lihir Island, Papua New Guinea: a reconnaissance study (United States)

    Müller, Daniel; Kaminski, Klaus; Uhlig, Stephan; Graupner, Torsten; Herzig, Peter M.; Hunt, Steve


    The exceptionally large gold resource at Ladolam (>1,300 metric tons of gold), Lihir Island, resulted from the transition of an early-stage, low-grade porphyry gold system to a low-sulfidation epithermal gold event. This transition was probably triggered by rapid decompression during the partial slope failure of Luise stratovolcano and accompanied by the ingress of seawater. The original porphyry stage is indicated by remnant hydrothermal breccia clasts of strongly biotite-magnetite altered monzodiorite with disseminated pyrite ± chalcopyrite and poorly developed pyrite ± quartz stockwork veins. The breccias are overprinted by biotite-magnetite alteration and their matrix is strongly mineralized with disseminated auriferous pyrite. The breccias are cut by late-stage epithermal quartz-chalcedony-illite-adularia-pyrite veins and associated illite-adularia alteration that locally contain bonanza gold grades of up to 120 g/t. Isotope data suggest a magmatic source of sulfur in the gold-bearing fluids at Ladolam. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at

  19. Characterization of Two Microbial Isolates from Andean Lakes in Bolivia (United States)

    Demergasso, C.; Blamey, J.; Escudero, L.; Chong, G.; Casamayor, E. O.; Cabrol, N. A.; Grin, E. A.; Hock, A.; Kiss, A.; Borics, G.


    We are currently investigating the biological population present in the highest and least explored perennial lakes on earth in the Bolivian and Chilean Andes, including several volcanic crater lakes of more than 6000 m elevation, in combination of microbiological and molecular biological methods. Our samples were collected in saline lakes of the Laguna Blanca Laguna Verde area in the Bolivian Altiplano and in the Licancabur volcano crater (27 deg. 47 min S/67 deg. 47 min. W) in the ongoing project studying high altitude lakes. The main goal of the project is to look for analogies with Martian paleolakes. These Bolivian lakes can be described as Andean lakes following the classification of Chong. We have attempted to isolate pure cultures and phylogenetically characterize prokaryotes that grew under laboratory conditions. Sediment samples taken from the Licancabur crater lake (LC), Laguna Verde (LV), and Laguna Blanca (LB) were analyzed and cultured using enriched liquid media under both aerobic and anaerobic conditions. All cultures were incubated at room temperature (15 to 20 C) and under light exposure. For the reported isolates, 36 hours incubation were necessary for reaching optimal optical densities to consider them viable cultures. Ten serial dilutions starting from 1% inoculum were required to obtain a suitable enriched cell culture to transfer into solid media. Cultures on solid medium were necessary to verify the formation of colonies in order to isolate pure cultures. Different solid media were prepared using several combinations of both trace minerals and carbohydrates sources in order to fit their nutrient requirements. The microorganisms formed individual colonies on solid media enriched with tryptone, yeast extract and sodium chloride. Cells morphology was studied by optical and electronic microscopy. Rodshape morphologies were observed in most cases. Total bacterial genomic DNA was isolated from 50 ml late-exponential phase culture by using the CTAB

  20. Allantoplacental ultrastructure of an Andean population of Mabuya (Squamata, Scincidae). (United States)

    Ramírez-Pinilla, Martha Patricia; De Pérez, Gloria; Carreño-Escobar, J Fernando


    Mabuya species are highly matrotrophic viviparous lizards with Type IV epitheliochorial allantoplacenta. The allantoplacenta of an Andean population of this genus, currently assigned to Mabuya sp., possesses specializations related to histotrophic nutrition at the embryonic hemisphere (placentome, paraplacentome, and chorionic areolas), while at the abembryonic hemisphere it has a mixed function: histotrophic transfer (absorptive plaques) and hemotrophic nutrition (gas exchange in respiratory segments). These placental specializations were studied using high-resolution light microscopy and transmission electron microscopy, and were compared with those found in other squamate reptiles and eutherian mammals. Cytological features of the placentome suggest that this is an important region for nutritional provision; the paraplacentome also shows characteristics for nutrient transfer, especially lipids. Chorionic areolas allow the absorption of glandular products, as well as uterine and chorionic cellular debris produced by lysis of some cells of both epithelia during areola formation. In the absorptive plaques both uterine and chorionic epithelia are firmly attached and their cellular apices exhibit electron-dense granules that could be related to autocrine and paracrine functions. The short interhemal distance found in the respiratory segments confirms their role in gas exchange. A common feature of all regional specializations in the Mabuya sp. allantoplacenta is the presence of lipids in the interacting chorionic and uterine epithelia, suggesting that lipids are transferred throughout the entire embryonic chamber; placental transfer of lipids may be the principal fetal energy and lipid source in this species. In spite of this feature, each one of the specialized areas of the allantoplacenta has different features suggesting particular functions in the transfer of nutrients (as ions, lipids, proteins, amino acids, sugar, water, and gases), and in the possible

  1. Assessment of satellite rainfall products over the Andean plateau (United States)

    Satgé, Frédéric; Bonnet, Marie-Paule; Gosset, Marielle; Molina, Jorge; Hernan Yuque Lima, Wilson; Pillco Zolá, Ramiro; Timouk, Franck; Garnier, Jérémie


    Nine satellite rainfall estimations (SREs) were evaluated for the first time over the South American Andean plateau watershed by comparison with rain gauge data acquired between 2005 and 2007. The comparisons were carried out at the annual, monthly and daily time steps. All SREs reproduce the salient pattern of the annual rain field, with a marked north-south gradient and a lighter east-west gradient. However, the intensity of the gradient differs among SREs: it is well marked in the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis 3B42 (TMPA-3B42), Precipitation Estimation from remotely Sensed Information using Artificial Neural Networks (PERSIANN) and Global Satellite Mapping of Precipitation (GSMaP) products, and it is smoothed out in the Climate prediction center MORPHing (CMORPH) products. Another interesting difference among products is the contrast in rainfall amounts between the water surfaces (Lake Titicaca) and the surrounding land. Some products (TMPA-3B42, PERSIANN and GSMaP) show a contradictory rainfall deficit over Lake Titicaca, which may be due to the emissivity contrast between the lake and the surrounding lands and warm rain cloud processes. An analysis differentiating coastal Lake Titicaca from inland pixels confirmed this trend. The raw or Real Time (RT) products have strong biases over the study region. These biases are strongly positive for PERSIANN (above 90%), moderately positive for TMPA-3B42 (28%), strongly negative for CMORPH (- 42%) and moderately negative for GSMaP (- 18%). The biases are associated with a deformation of the rain rate frequency distribution: GSMaP underestimates the proportion of rainfall events for all rain rates; CMORPH overestimates the proportion of rain rates below 2 mm day- 1; and the other products tend to overestimate the proportion of moderate to high rain rates. These biases are greatly reduced by the gauge adjustment in the TMPA-3B42, PERSIANN and CMORPH products, whereas a

  2. Andean uplift and Neogene climate change in the Atacama Desert (United States)

    Rech, J. A.; Currie, B. S.; Jordan, T. E.


    Today the Andean Cordillera and Altiplano provide a major obstacle to atmospheric circulation over South America. The Altiplano Plateau prevents moist air masses from the Amazon Basin from reaching the Atacama Desert, causing the Atacama to be one of the driest places on Earth. Although Neogene sedimentary records from the western flank of the Andes should record the dramatic shift to hyperaridity that resulted from the growth of the Altiplano Plateau, the climatic implications of many sedimentary sequences have been difficult to decipher. The causes of the difficulties are complex, such as the relative influences of tectonics and active volcanism versus climate, and the roles of local as well as regional precipitation on groundwater and on the deposition of paludal sediments in basin centers. Over the last few years our research group has focused on using paleosols and the isotopic composition of palustrine carbonates in the Calama Basin (22°S) to try to identify a local precipitation signal and determine the onset of extreme hyperaridity as a consequence of the growth of the Altiplano. We have determined the soil morphological characteristics, salt chemistry, and mass independent fractionation anomalies (Δ17O values) in dated paleosols to reconstruct a Middle Miocene climatic transition from semi-aridity to extreme hyperaridity in the Atacama Desert. Paleosols along the southeastern margin of the Calama Basin change from calcic Vertisols with root traces, slickensides, and gleyed horizons to an extremely mature salic Gypsisol with pedogenic nitrate. We interpret this transition, which occurred between 19 and 13 Ma, to represent a change in precipitation from >200 mm/yr to Calama Basin also show a marked change during this time period. δ13C values of palustrine carbonates increase from -7 to +7? VPDB and δ18O values increases from -7 to +1? VPDB over the late to Middle Miocene time. This major trend towards more positive values is likely the result of several

  3. Marcos Zapata's "Last Supper": a feast of European religion and Andean culture. (United States)

    Zendt, Christina


    In Marcos Zapata's 1753 painting of the Last Supper in Cuzco, Peru, Christian symbolism is filtered through Andean cultural tradition. Zapata was a late member of the Cuzco School of Painting, a group comprised of few European immigrants and handfuls of mestizo and Indian artists. The painters in Cuzco learned mostly from prints of European paintings, and their style tends to blend local culture into the traditional painting of their conquistadors. Imagery was the most successful tool used by the Spaniards in their quest to Christianize the Andean population. By teaching locals to paint Christian subjects, they were able to infuse Christianity into Andean traditions. Zapata's rendering of the Last Supper utilizes this cultural blending while staying true to the Christian symbolism within the subject. Instead of the traditional lamb, Zapata's Last Supper features a platter of cuy, or guinea pig, an Andean delicacy stocked with protein as well as cultural significance. Cuy was traditionally a sacrificial animal at Inca agricultural festivals and in this way it offers poignant parallel to the lamb, as a traditional Christian sacrificial animal.

  4. The electronic procurement in the framework of the Andean Community. State of the art

    Directory of Open Access Journals (Sweden)

    William David Hernández Martínez


    Full Text Available The article is structured as a brief survey of the academic and policy approach on the unification or harmonization of regulations about electronic commerce, specifically relating the electronic contracts, in Latin America, with special emphasis on the Andean Community of Nations as a proposed work on the development of modern trends of international trade law.

  5. Taxonomic and functional assignment of cloned sequences from high Andean forest soil metagenome

    NARCIS (Netherlands)

    Montaña, José Salvador; Jiménez Avella, Diego; Angel, Tatiana; Hernández, Mónica; Baena, Sandra


    Total metagenomic DNA was isolated from high Andean forest soil and subjected to taxonomical and functional composition analyses by means of clone library generation and sequencing. The obtained yield of 1.7 μg of DNA/g of soil was used to construct a metagenomic library of approximately 20,000 clon

  6. A novel cold active esterase derived from Colombian high Andean forest soil metagenome

    NARCIS (Netherlands)

    Jiménez, Diego Javier; Montaña, José Salvador; Alvarez, Diana; Baena, Sandra


    In order to search new lipolytic enzymes and conduct bioprospecting of microbial communities from high Andean forest soil, a metagenomic library of approximately 20,000 clones was constructed in Escherichia coli using plasmid p-Bluescript II SK+. The library covered 80 Mb of the metagenomic DNA main

  7. Forests of the tropical eastern Andean flank during the middle Pleistocene

    NARCIS (Netherlands)

    Cárdenas, M.L.; Gosling, W.D.; Pennington, R.T.; Poole, I.; Sherlock, S.C.; Mothes, P.


    Inter-bedded volcanic and organic sediments from Erazo (Ecuador) indicate the presence of four different forest assemblages on the eastern Andean flank during the middle Pleistocene. Radiometric dates (40Ar-39Ar) obtained from the volcanic ash indicate that deposition occurred between 620,000 and 19

  8. Persistence of chironomids in metal polluted Andean high altitude streams: does melanin play a role?

    NARCIS (Netherlands)

    Loayza Muro, R.A.; Marticorena-Ruíz, J.K.; Palomino, E.J.; Merritt, C.; de Baat, M.L.; van Gemert, M.; Verweij, R.A.; Kraak, M.H.S.; Admiraal, W.


    In high altitude Andean streams an intense solar radiation and coinciding metal pollution allow the persistence of only a few specialized taxa, including chironomids. The aim of the present study was therefore to determine the mechanisms underlying the persistence of chironomids under these multiple

  9. 77 FR 24555 - Andean Trade Preference Act (ATPA), as Amended: Request for Public Comments Regarding Beneficiary... (United States)


    ... From the Federal Register Online via the Government Publishing Office OFFICE OF THE UNITED STATES...., provides trade benefits for eligible Andean countries. The original Act allowed only Bolivia, Ecuador... Bolivia no longer satisfies the eligibility criteria related to counternarcotics and suspended...

  10. 75 FR 19669 - Andean Trade Preference Act (ATPA), as Amended: Request for Public Comments Regarding Beneficiary... (United States)


    ... From the Federal Register Online via the Government Publishing Office OFFICE OF THE UNITED STATES... eligible Andean countries. In Proclamation 7616 of October 31, 2002, the President designated Bolivia... President determined that Bolivia no longer satisfies the eligibility criteria related to...

  11. Formal Law and Local Water Control in the Andean Region: A Fiercely Contested Field

    NARCIS (Netherlands)

    Vos, de H.; Boelens, R.A.; Bustamente, R.R.


    Water access and control rights of peasant and indigenous communities in Andean countries are threatened. Vertical state law and intervention practices, as well as new privatization policies generally ignore, discriminate or undermine local normative frameworks. Recognition of diverse local rights a

  12. Institutional reform in the Andean irrigation sector: enabling policies for strengthening local rights and water management

    NARCIS (Netherlands)

    Cremers, L.; Ooijevaar, M.; Boelens, R.A.


    For centuries, local and indigenous water rights and rules in the Andean region have been largely neglected and discriminated against. The process of undermining local communities' water access and control rights continues up to today and not only is it headed by powerful local, national and interna

  13. The abiotic and biotic drivers of rapid diversification in Andean bellflowers (Campanulaceae). (United States)

    Lagomarsino, Laura P; Condamine, Fabien L; Antonelli, Alexandre; Mulch, Andreas; Davis, Charles C


    The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity.

  14. The Rise and Fall of Andean Empires: El Nino History Lessons. (United States)

    Wright, Kenneth R.


    Provides information on El Nino and the methods for investigating ancient climate record. Traces the rise and fall of the Andean empires focusing on the climatic forces that each empire (Tiwanaku, Wari, Moche, and Inca) endured. States that modern societies should learn from the experiences of these ancient civilizations. (CMK)

  15. Early Paleozoic magmatism and metallogeny in Northeast China: a record from the Tongshan porphyry Cu deposit (United States)

    Hu, Xinlu; Yao, Shuzhen; Ding, Zhenju; He, Mouchun


    The Tongshan Cu deposit is located in the northern segment of the Great Xing'an Range and represents one of the few early Paleozoic porphyry Cu deposits in northeastern China. The granitic rocks in the Tongshan Cu deposit include concealed granodiorite and exposed tonalite, which yield LA-ICP-MS zircon U-Pb ages of 478 ± 3 Ma and 214 ± 3 Ma, respectively. The granodiorite has relatively high SiO2 (60.5-63.5 wt%) and Sr (596-786 ppm) contents, low Yb (1.21-1.53 ppm) and Y (9.81-13.0 ppm) contents, and initial 87Sr/86Sr ratios (0.7038-0.7040), suggesting adakitic affinity. Combined with its positive ɛNd( t) values (3.5-5.4), low Mg# values (41-50), and low contents of Cr (18.6-29.0 ppm) and Ni (7.3-9.1 ppm), we propose an origin by partial melting of a juvenile mafic lower crust in a post-collisional setting after the amalgamation of the Erguna and Xing'an Blocks. The tonalite is characterized by high SiO2 (63.1-65.9 wt%) and Al2O3 (16.0-16.3 wt%) contents, low (87Sr/86Sr) i ratios (0.7041-0.7042), positive ɛNd( t) values (2.6-3.0), along with LILE and LREE enrichments and Nb-Ta-Ti depletions, suggesting an origin by partial melting of juvenile mafic lower crust, coupled with fractional crystallization, in a post-orogenic setting after the collision between the Xing'an and Songnen Blocks. The δD values of ore-forming fluids range from -100 to -93 ‰, and the δ18O values calculated from hydrothermal quartz are between -3 and 10 ‰. The δ34S values of sulfides vary from -2.6 to -1.1 ‰. Field observations, as well as the geochronological and H-O-S isotopic data, suggest that the Cu mineralization at Tongshan was genetically linked with the granodiorite.


    Institute of Scientific and Technical Information of China (English)

    王奖臻; 胡瑞忠; 孙燕; 陆彦; 李泽琴



  17. 10Be surface exposure dating reveals strong active deformation in the central Andean backarc interior (United States)

    García Morabito, Ezequiel; Terrizzano, Carla; Zech, Roland; Willett, Sean; Yamin, Marcela; Haghipour, Negar; Wuethrich, Lorenz; Christl, Marcus; María Cortes, José; Ramos, Victor


    Understanding the deformation associated with active thrust wedges is essential to evaluate seismic hazard. How is active faulting distributed throughout the wedge, and how much deformation is taken up by individual structures? We address these questions for our study region, the central Andean backarc of Argentina. We combined a structural and geomorphological approach with surface exposure dating (10Be) of alluvial fans and strath terraces in two key localities at ~32° S: the Cerro Salinas, located in the active orogenic front of the Precordillera, and the Barreal block in the interior of the Andean mountain range. We analysed 22 surface samples and 6 depth profiles. At the thrust front, the oldest terrace (T1) yields an age of 100-130 ka, the intermediate terrace (T2) between 40-95 ka, and the youngest terrace (T3) an age of ~20 ka. In the Andean interior, T1´ dates to 117-146 ka, T2´ to ~70 ka, and T3´ to ~20 ka, all calculations assuming negligible erosion and using the scaling scheme for spallation based on Lal 1991, Stone 2000. Vertical slip rates of fault offsets are 0.3-0.5 mm/yr and of 0.6-1.2 mm/yr at the thrust front and in the Andean interior, respectively. Our results highlight: i) fault activity related to the growth of the Andean orogenic wedge is not only limited to a narrow thrust front zone. Internal structures have been active during the last 150 ka, ii) deformation rates in the Andean interior are comparable or even higher that those estimated and reported along the emerging thrust front, iii) distribution of active faulting seems to account for unsteady state conditions, and iv) seismic hazards may be more relevant in the internal parts of the Andean orogen than assumed so far. References Lal, D., 1991: Cosmic ray labeling of erosion surfaces: In situ nuclide production rates and erosion models. Earth and Planetary Science Letters 104: 424-439. Stone, J.O., 2000: Air pressure and cosmogenic isotope production. Journal of Geophysical

  18. Petrogenesis of Paleocene-Eocene porphyry deposit-related granitic rocks in the Yaguila-Sharang ore district, central Lhasa terrane, Tibet (United States)

    Zhao, Junxing; Li, Guangming; Evans, Noreen J.; Qin, Kezhang; Li, Jinxiang; Zhang, Xia'nan


    The Paleocene-Eocene ore deposits in the Gangdese Metallogenic Belt, Tibet, are thought to have been formed during the main period of India-Asia continental collision. This paper reports the whole-rock major element, trace element, and Sr-Nd-Hf isotopic compositions and zircon trace element contents of volcanic and intrusive rocks from the Paleocene Yaguila skarn Pb-Zn-Ag deposit and adjacent Eocene Sharang porphyry Mo deposit in the central Lhasa terrane, Tibet. Geochemical signatures and Nd-Hf isotopic compositions indicate that the Yaguila Cretaceous rhyolitic rocks were formed by the melting of ancient continental crust, whereas the Paleocene causative granite porphyry may have resulted from the interaction between mantle-derived and crustal-derived materials when continental collision was initiated. The dramatic increase of εNd(t) values between emplacement of the granite porphyry and later porphyritic biotite granite suggests a greater involvement of mantle materials during the crystallization of the barren biotite granite stock. The post-ore Miocene granodiorite porphyry has a similar geochemical signature to the Sharang Miocene dykes, suggesting they were both generated from melting of enriched lithospheric mantle. Nd-Hf mixing calculations indicate an increasing contribution of mantle materials in Paleocene to Eocene intrusions, consistent with the regional tectonic model of Neo-Tethyan oceanic slab roll-back and break-off. Zircons from both the Yaguila and Sharang ore-related porphyries have higher Ce anomalies than those from the barren granitoids, suggesting that Mo mineralization was closely related to highly oxidized and differentiated magma. The fertile intrusions in the Yaguila-Sharang district contain EuN/EuN∗ values from 0.3 to 0.6, higher than the non-mineralized intrusions. The processes of early crystallization of plagioclase and/or SO2-degassing from underlying magma can explain the observed negative Eu anomalies in zircon.

  19. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk (United States)

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo


    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation. PMID:26986004

  20. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk. (United States)

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo


    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.

  1. Reconciling Local and Global Agendas in Sustainable Development: Participatory Research with Indigenous Andean Communities

    Institute of Scientific and Technical Information of China (English)

    Robert E. Rhoades; Virginia Nazarea


    This paper discusses participatory research in the Andes and presents a case study in Cotacachi, Ecuador, where sustainability scientists and indigenous people seek common ground in their respective but drastically different research and social agendas. Participatory research based on Andean experiences pre-dated and inspired much of the later international movement in agriculture, health, and conservation. Andean communities have a long history in demanding that outsiders address the needs of the community as a condition for carrying out scientific or applied activities. What an Andean community, however, sees as relevant may or may not practiced throughout much of the world. In fact,overzealous participatory researchers are just as bothersome as their predecessors bearing long questionnaires. More important to Andean people is an equitable relationship with researchers and developers in which exchanges of value are made. A research is drawn. In the case of the SANREM project in Cotacachi, Ecuador, scientists carried out enriching research activities of interest to local people as a way to generate social capital for conducting basic research which does not have an obvious, immediate local benefit. The requested research did not have a conventional participatory methodology but provided valuable products (educational opportunity,germplasm, community visualization tools, and information) to the indigenous community in exchange for time and resources to conduct research on more basic natural resource questions. We argue that in the Andean context the key to reconciling the needs of scientists and of local needs is seeking new forms of equitable collaboration which reach beyond the present and now somewhat tired discourse of ‘participation'.

  2. Andean Condor (Vultur gryphus in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

    Directory of Open Access Journals (Sweden)

    Adrián Naveda-Rodríguez

    Full Text Available The Andean Condor (Vultur gryphus in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.

  3. Identifying signatures of natural selection in Tibetan and Andean populations using dense genome scan data.

    Directory of Open Access Journals (Sweden)

    Abigail Bigham


    Full Text Available High-altitude hypoxia (reduced inspired oxygen tension due to decreased barometric pressure exerts severe physiological stress on the human body. Two high-altitude regions where humans have lived for millennia are the Andean Altiplano and the Tibetan Plateau. Populations living in these regions exhibit unique circulatory, respiratory, and hematological adaptations to life at high altitude. Although these responses have been well characterized physiologically, their underlying genetic basis remains unknown. We performed a genome scan to identify genes showing evidence of adaptation to hypoxia. We looked across each chromosome to identify genomic regions with previously unknown function with respect to altitude phenotypes. In addition, groups of genes functioning in oxygen metabolism and sensing were examined to test the hypothesis that particular pathways have been involved in genetic adaptation to altitude. Applying four population genetic statistics commonly used for detecting signatures of natural selection, we identified selection-nominated candidate genes and gene regions in these two populations (Andeans and Tibetans separately. The Tibetan and Andean patterns of genetic adaptation are largely distinct from one another, with both populations showing evidence of positive natural selection in different genes or gene regions. Interestingly, one gene previously known to be important in cellular oxygen sensing, EGLN1 (also known as PHD2, shows evidence of positive selection in both Tibetans and Andeans. However, the pattern of variation for this gene differs between the two populations. Our results indicate that several key HIF-regulatory and targeted genes are responsible for adaptation to high altitude in Andeans and Tibetans, and several different chromosomal regions are implicated in the putative response to selection. These data suggest a genetic role in high-altitude adaption and provide a basis for future genotype/phenotype association

  4. Shifts in leaf litter breakdown along a forest-pasture-urban gradient in Andean streams. (United States)

    Iñiguez-Armijos, Carlos; Rausche, Sirkka; Cueva, Augusta; Sánchez-Rodríguez, Aminael; Espinosa, Carlos; Breuer, Lutz


    Tropical montane ecosystems of the Andes are critically threatened by a rapid land-use change which can potentially affect stream variables, aquatic communities, and ecosystem processes such as leaf litter breakdown. However, these effects have not been sufficiently investigated in the Andean region and at high altitude locations in general. Here, we studied the influence of land use (forest-pasture-urban) on stream physico-chemical variables (e.g., water temperature, nutrient concentration, and pH), aquatic communities (macroinvertebrates and aquatic fungi) and leaf litter breakdown rates in Andean streams (southern Ecuador), and how variation in those stream physico-chemical variables affect macroinvertebrates and fungi related to leaf litter breakdown. We found that pH, water temperature, and nutrient concentration increased along the land-use gradient. Macroinvertebrate communities were significantly different between land uses. Shredder richness and abundance were lower in pasture than forest sites and totally absent in urban sites, and fungal richness and biomass were higher in forest sites than in pasture and urban sites. Leaf litter breakdown rates became slower as riparian land use changed from natural to anthropogenically disturbed conditions and were largely determined by pH, water temperature, phosphate concentration, fungal activity, and single species of leaf-shredding invertebrates. Our findings provide evidence that leaf litter breakdown in Andean streams is sensitive to riparian land-use change, with urban streams being the most affected. In addition, this study highlights the role of fungal biomass and shredder species (Phylloicus; Trichoptera and Anchytarsus; Coleoptera) on leaf litter breakdown in Andean streams and the contribution of aquatic fungi in supporting this ecosystem process when shredders are absent or present low abundance in streams affected by urbanization. Finally, we summarize important implications in terms of managing of

  5. Chronic hypoxia in Andeans; are there lessons for neurology at sea level? (United States)

    Appenzeller, Otto; Minko, Tamara; Qualls, Clifford; Pozharov, Vitaly; Gamboa, Jorge; Gamboa, Alfredo; Pakunlu, Rafica I


    Hypoxia is implicated in aging and neurodegenerative diseases. We posited that changes in gene expression induced by ambient hypoxia at altitude may be neuroprotective to natives of these regions. We studied 30 men. Twenty natives of Cerro de Pasco (CP), altitude 4,338 m were examined in CP; then transported within 6 h to Lima (150 m-sea level) and examined 1 h after arrival. They were assessed by a Chronic Mountain Sickness-score (CMS-sc) in CP, 10 were normal Andeans and 10 had chronic mountain sickness (CMS), a sudden inexplicable loss of adaptation to their native environment. RNA was extracted from venous blood white cells. The Andeans were compared to 10 normal US men living at 1500 m using RT-PCR. We focused on the cyto-neuro-protective genes, Ataxia telangiectasia mutated (ATM), heme-oxygenase-1 (HMOX 1), heat shock protein-70 (HSP-70), heat shock protein-90 (HSP-90), and the neuroprotective enzyme, nicotinamide mononucleotide adenylyl transferase 1 (Nnmat 1). CMS patients had significantly higher levels of gene expression (HMOX-1, HSP-70, ATM) than Andean controls in CP. HSP-90 and Nmnat 1, however, were higher in Andean controls in all locations. Significant reductions of all gene products, within an hour of arriving in normoxia in Lima, were found. In Andean controls, the gene products in Lima fell to levels approaching US controls. Correlation and regression methods showed men with high expression of all gene products had an average CMS-sc=19.8; those with low expression a normal score (9.4, P=0.02). ATM expression was related to age (P<0.001). The natural experiment that unfolds in the mountainous regions of the world provides opportunities to study neuroprotection in intact humans.

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

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


    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

  7. [Copper pathology (author's transl)]. (United States)

    Mallet, B; Romette, J; Di Costanzo, J D


    Copper is an essential dietary component, being the coenzyme of many enzymes with oxidase activity, e.g. ceruloplasmin, superoxide dismutase, monoamine oxidase, etc. The metabolism of copper is complex and imperfectly known. Active transport of copper through the intestinal epithelial cells involves metallothionein, a protein rich in sulfhydryl groups which also binds the copper in excess and probably prevents absorption in toxic amounts. In hepatocytes a metallothionein facilitates absorption by a similar mechanism and regulates copper distribution in the liver: incorporation in an apoceruloplasmin, storage and synthesis of copper-dependent enzymes. Metallothioneins and ceruloplasmin are essential to adequate copper homeostasis. Apart from genetic disorders, diseases involving copper usually result from hypercupraemia of varied origin. Wilson's disease and Menkes' disease, although clinically and pathogenetically different, are both marked by low ceruloplasmin and copper serum levels. The excessive liver retention of copper in Wilson's disease might be due to increased avidity of hepatic metallothioneins for copper and decreased biliary excretion through lysosomal dysfunction. Menkes' disease might be due to low avidity of intestinal and hepatic metallothioneins for copper. The basic biochemical defect responsible for these two hereditary conditions has not yet been fully elucidated.

  8. Devonian and carboniferous arcs of the oyu tolgoi porphyry Cu-Au district, South Gobi region, Mongolia (United States)

    Wainwright, A.J.; Tosdal, R.M.; Forster, C.N.; Kirwin, D.J.; Lewis, P.D.; Wooden, J.L.


    The Central Asian orogenic belt consists of microcontinental blocks and mobile belts positioned between the Siberian craton and the Tarim and North China cratons. Extending across Asia for 5000 km, the belt consists of terranes that decrease in age southward away from the Siberian craton. A time-stratigraphic-structural sequence for the rocks is critical to defining the tectonic evolution of the belt. In the Oyu Tolgoi area of the South Gobi Desert (Mongolia), Devonian and Carboniferous rocks record the construction of multiple arcs, formation of a giant porphyry Cu-Au system, exhumation, and polyphase deformation. The oldest rocks are basaltic volcanic and subvolcanic rocks of the Devonian Alagbayan Group intruded by Late Devonian quartz monzodiorite stocks and dikes, which host giant porphyry Cu-Au deposits. The rocks were exhumed, overlain by pyroclastic rocks, and then tectonically buried by marine mafic supracrustal rocks prior to the youngest Devonian granodiorite intrusions. The postmineral Carboniferous Gurvankharaat Group unconformably overlying the deformed terrane consists of effusive, pyroclastic, subvolcanic and volcaniclastic rocks, as well as sedimentary units. The supracrustal rocks underwent polyphase shortening after 330 Ma and prior to 290 Ma. Variations in stratigraphic sequences suggest that the region is underlain by a submarine arc that became emergent during the Upper Devonian and remained subaerial to shallow subaqueous through much of the Carboniferous. Xenocrystic zircons in igneous rocks suggest that the offshore arcs were sufficiently close to ancient crust to have interacted with detritus shed into marine basins, most likely from the Siberian craton and fringing early Paleozoic terranes. ?? 2011 Geological Society of America.

  9. Garnet-bearing tonalitic porphyry from East Kunlun, Northeast Tibetan Plateau: implications for adakite and magmas from the MASH Zone (United States)

    Yuan, Chao; Sun, Min; Xiao, Wenjiao; Wilde, Simon; Li, Xianhua; Liu, Xiaohan; Long, Xiaoping; Xia, Xiaoping; Ye, Kai; Li, Jiliang


    A garnet-bearing tonalitic porphyry from the Achiq Kol area, northeast Tibetan Plateau has been dated by SHRIMP U-Pb zircon techniques and gives a Late Triassic age of 213 ± 3 Ma. The porphyry contains phenocrysts of Ca-rich, Mn-poor garnet (CaO > 5 wt%; MnO 17 wt%) contents, and is metaluminous to slightly peraluminous (ACNK = 0.89-1.05). The rock samples are enriched in LILE and LREE but depleted in Nb and Ti, showing typical features of subduction-related magmas. The relatively high Sr/Y (~38) ratios and low HREE (Yb residual phase, while suppressed crystallization of plagioclase and lack of negative Eu anomalies indicate a high water fugacity in the magma. Nd-Sr isotope compositions of the rock (ɛNdT = -1.38 to -2.33; 87Sr/86Sri = 0.7065-0.7067) suggest that both mantle- and crust-derived materials were involved in the petrogenesis, which is consistent with the reverse compositional zoning of plagioclase, interpreted to indicate magma mixing. Both garnet phenocrysts and their ilmenite inclusions contain low MgO contents which, in combination with the oxygen isotope composition of garnet separates (+6.23‰), suggests that these minerals formed in a lower crust-derived felsic melt probably in the MASH zone. Although the rock samples are similar to adakitic rocks in many aspects, their moderate Sr contents (residual melt. It is suggested that extensive crystallization of apatite as an early phase may prevent some arc magmas from evolving into adakitic rocks even under high water fugacity.

  10. Sr-Nd-Pb-Hf isotope systematics of the Hugo Dummett Cu-Au porphyry deposit (Oyu Tolgoi, Mongolia) (United States)

    Dolgopolova, A.; Seltmann, R.; Armstrong, R.; Belousova, E.; Pankhurst, R. J.; Kavalieris, I.


    Major and trace element geochemistry including Sr-Nd-Pb-Hf isotopic data are presented for a representative sample suite of Late Devonian to Early Carboniferous plutonic and volcanic rocks from the Hugo Dummett deposit of the giant Oyu Tolgoi porphyry Cu-Au district in South Gobi, Mongolia. Sr and Nd isotopes (whole-rock) show restricted ranges of initial compositions, with positive ɛNdt mainly between + 3.4 and + 7.4 and (87Sr/86Sr)t predominantly between 0.7037 and 0.7045 reflecting magma generation from a relatively uniform juvenile lithophile-element depleted source. Previously dated zircons from the plutonic rocks exhibit a sample-averaged range of ɛHft values of + 11.6 to + 14.5. Depleted-mantle model ages of 420-830 (Nd) and 320-730 Ma (zircon Hf) limit the involvement of pre-Neoproterozoic crust in the petrogenesis of the intermediate to felsic calc-alkaline magmas to, at most, a minor role. Pb isotopes (whole-rock) show a narrow range of unradiogenic initial compositions: 206Pb/204Pb 17.40-17.94, 207Pb/204Pb 15.43-15.49 and 208Pb/204Pb 37.25-37.64, in agreement with Sr-Nd-Hf isotopes indicating the dominance of a mantle component. All four isotopic systems suggest that the magmas from which the large Oyu Tolgoi porphyry system was generated originated predominantly from juvenile material within the subduction-related setting of the Gurvansayhan terrane.

  11. [Copper IUDs (author's transl)]. (United States)

    Thiery, M


    Following initial development of the Grafenberg ring in the 1920's, IUDs fell into disuse until the late 1950s, when plastic devices inserted using new technology began to gain worldwide acceptance. Further research indicated that copper had a significant antifertility effect which increased with increasing surface area, and several copper IUDs were developed and adapted, including the Copper T 200, the Copper T 220C, and the Copper T 380 A, probably the most effective yet. The Gravigard and Multiload are 2 other copper devices developed according to somewhat different principles. Copper devices are widely used not so much because of their great effectiveness as because of their suitability for nulliparous patients and their ease of insertion, which minimizes risk of uterine perforation. Records of 2584 women using Copper IUDs for 7190 women-years and 956 women using devices without copper for 6059 women-years suggest that the copper devices were associated with greater effectiveness and fewer removals for complications. Research suggests that the advantages of copper IUDs become more significant with increased duration of use. Contraindications to copper devices include allergy to copper and hepatolenticular degeneration. No carcinogenic or teratogenic effect of copper devices has been found, but further studies are needed to rule out other undesirable effects. Significant modifications of copper devices in recent years have been developed to increase their effectiveness, prolong their duration of usefulness, facilitate insertion and permit insertion during abortion or delivery. The upper limit of the surface area of copper associated with increased effectiveness appears to be between 200-300 sq mm, and at some point increases in copper exposure may provoke expulsion of the IUD. The duration of fertility inhibition of copper IUDs is usually estimated at 2-3 years, but recent research indicates that it may be 6-8 years, and some devices may retain copper surface

  12. Copper deposit resource potential and prospecting targets in Afghanistan%阿富汗铜矿资源潜力与找矿方向

    Institute of Scientific and Technical Information of China (English)

    高辉; 梅燕雄; 王浩琳; 范世家


    Afghanistan is located in the convergence of Ancient India subcontinent and Asia plate, and it is sure to be a preferable regional prospecting area where Tethys - Himalaya metallogenic belt and magmatic arc running through. There are good conditions for mineralization and extremely metal - rich mineral resources in the region. About more than 300 documented copper deposits (occurrences) have been discovered in Afghanistan, which are composed of sediment - hosted, skarn, porphyry and vein -hosted type, including the world - class sedimentary stratabound Aynak deposit. The research indicates that Tethys - Himalaya metallogenic belt has undergone alternative deposition and uplift during the old and new Tethys Ocean's expansion and closure, and two large - scale phases of subduction and collision of tectonic plate as well, and then folded and formed the youngest Mesozoic and Cenozoic Orogenic Belts on Earth. Afghanistan has also undergone a complicated tectonic evolution of long history with regional metallogenic background environment' s conversion from the former Cambrian inner continent to convergent orogenic environment. The pre Neo - proterozoic and Meso - proterozoic ore - sourced terranes and the magma reactivated, and the magmatism and derivative mineralization/process occurred, and the mineralization had the favorable conditions such as the mineralization preferentiality and the best coupling. The porphyry copper deposits and sand shale copper deposits developed broadly in Afghanistan with huge copper resources potential. The sand shale copper deposits and the porphyry copper deposits are significant exploration targets. The skarn copper deposits and vein copper deposits, which developed broadly, are the symbols and favorable zones for deep exploration of porphyry copper/gold deposit.%阿富汗位于远古印度次大陆同亚洲大陆板块碰撞的交汇处,也是全球性成矿带——特提斯—喜马拉雅造山带(岩浆弧)成矿有利区段,金属

  13. Geological, geochronological, geochemical, and Sr-Nd-O-Hf isotopic constraints on origins of intrusions associated with the Baishan porphyry Mo deposit in eastern Tianshan, NW China (United States)

    Wang, Yinhong; Xue, Chunji; Liu, Jiajun; Zhang, Fangfang


    The Baishan porphyry Mo deposit (0.72 Mt; 0.06 % Mo) is located in the interior of the eastern Tianshan orogenic belt in Xinjiang, NW China. The deposit comprises 15 orebodies that are associated with monzogranite and granite porphyry stocks and are structurally controlled by roughly EW-trending faults. Secondary ion mass spectrometry (SIMS) zircon U-Pb dating of the monzogranite and granite porphyry yielded the Middle Triassic age (228 ± 2 to 227 ± 2 Ma), which coincide with the molybdenite Re-Os model ages ranging from 226 ± 3 to 228 ± 3 Ma. The Triassic monzogranite and granite porphyry belong to high-K calc-alkaline series and are characterized by high SiO2 and Al2O3 and low MgO, TiO2, and P2O5 concentrations, with negative Eu anomalies (δEu = 0.55-0.91). The least-altered monzogranite and granite porphyry yield uniform ɛ Nd( t) values from +1.6 to +3.6, and wide (87Sr/86Sr) i ratios ranging between 0.7035 and 0.7071, indicating that they were derived from the lower crust. In situ O-Hf isotopic analyses on zircon using SIMS and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) indicate that the δ18O and ɛ Hf( t) values of zircon from a monzogranite sample vary from 6.1 to 7.3 ‰ and +8.0 to +11.7, respectively, whereas zircon from a granite porphyry sample vary from 6.2 to 6.9 ‰ and +7.3 to +11.2, respectively. The geochemical and isotopic data imply that the primary magmas of the Baishan granite were likely derived from partial melts from the lower crust involving some mantle components. The Baishan Mo deposit and granitic emplacement were proposed to be most likely related to post-orogenic lithospheric extension and magmatic underplating. An extensional event coupled with the rising of hot mantle-derived melts triggered partial melting of the lower crust, as well as provided metals (Mo).

  14. U-Pb (zircon) and geochemical constraints on the age, origin, and evolution of Paleozoic arc magmas in the Oyu Tolgoi porphyry Cu-Au district, southern Mongolia (United States)

    Wainwright, A.J.; Tosdal, R.M.; Wooden, J.L.; Mazdab, F.K.; Friedman, R.M.


    Uranium-Pb (zircon) ages are linked with geochemical data for porphyry intrusions associated with giant porphyry Cu-Au systems at Oyu Tolgoi to place those rocks within the petrochemical framework of Devonian and Carboniferous rocks of southern Mongolia. In this part of the Gurvansayhan terrane within the Central Asian Orogenic Belt, the transition from Devonian tholeiitic marine rocks to unconformably overlying Carboniferous calc-alkaline subaerial to shallow marine volcanic rocks reflects volcanic arc thickening and maturation. Radiogenic Nd and Pb isotopic compositions (??Nd(t) range from +3.1 to +7.5 and 206Pb/204Pb values for feldspars range from 17.97 to 18.72), as well as low high-field strength element (HFSE) contents of most rocks (mafic rocks typically have rocks are dominantly medium- to high-K calc-alkaline and characterized by a decrease in Sr/Y ratios through time, with the Carboniferous rocks being more felsic than those of Devonian age. Porphyry Cu-Au related intrusions were emplaced in the Late Devonian during the transition from tholeiitic to calc-alkaline arc magmatism. Uranium-Pb (zircon) geochronology indicates that the Late Devonian pre- to syn-mineral quartz monzodiorite intrusions associated with the porphyry Cu-Au deposits are ~372Ma, whereas granodiorite intrusions that post-date major shortening and are associated with less well-developed porphyry Cu-Au mineralization are ~366Ma. Trace element geochemistry of zircons in the Late Devonian intrusions associated with the porphyry Cu-Au systems contain distinct Th/U and Yb/Gd ratios, as well as Hf and Y concentrations that reflect mixing of magma of distinct compositions. These characteristics are missing in the unmineralized Carboniferous intrusions. High Sr/Y and evidence for magma mixing in syn- to late-mineral intrusions distinguish the Late Devonian rocks associated with giant Cu-Au deposits from younger magmatic suites in the district. ?? 2010 Elsevier B.V.

  15. 东沟含钼斑岩由太山庙岩基派生?%Was Donggou porphyry Mo deposit derived from Taishanmiao batholith?

    Institute of Scientific and Technical Information of China (English)

    黄凡; 罗照华; 卢欣祥; 高飞; 陈必河; 杨宗锋; 潘颖; 李德东


    The Donggou porphyry Mo deposit, located in Ruyang County of Henan Province, is a giant ore deposit discovered in recent years. The Donggou molybdenum-bearing porphyry is considered to be an apophysis or a fractionated product from the adjacent Tai-shanmiao batholith. Accordingly, the ore-forming process of this deposit seems to be relevant to the differentiation of Taishanmiao batholitic magma. Based on an analysis of geology, petrology, geochemistry and temperature field. the authors hold that the Donggou granite porphyry is a preduct of another magmatic activity independent of Taishanmiao batholitic magma, as shown by the following evidence: ① Acoording to the age data available, the Taishanmiao hatholith was generated earlier than the Donggou porphyry by 3 Ma, suggesting that the two intrusions were not contemporaneous. ② The thickness of the Taishanmiao batholith is about 3.5 km and the exposed elevation is higher than Donggou porphyry by 600 m, and there are no larger faults within the distance of about 7 km between the intrusions. Such a spatial relationship is not consistent with the differentiation model of a deep magma chamber. ③ The Donggou porphyry, containing high-temperature quartz phenocrysts, is a product consolidated from the high temperature magma. On the contrary, the Taishanmiao hatholith is a pluton with relatively low initial temperature. ④ There are Pb-Zn ore deposits or spots composing a relatively complete ring with the Donggou porphyry as the center, showing that there existed a temperature field around the Donggou porphyry and that the temperature fidd was not destroyed by the heat from the Taishanmiao intrusion during mineraliza-tion. Therefore, the Donggou porphyry should not be considered as an apophysis or a product fractionated from the adjacent Taishan-miao hatholith. In addition, based on the average Mo concentration of granotoid and the latest experimental data of molybdenum solu-bility in the ore-bearing fluid, the mass

  16. Varying mechanical coupling along the Andean margin: Implications for trench curvature, shortening and topography (United States)

    Iaffaldano, G.; Di Giuseppe, E.; Corbi, F.; Funiciello, F.; Faccenna, C.; Bunge, H.-P.


    Convergent margins often exhibit spatial and temporal correlations between trench curvature, overriding plate shortening and topography uplift that provide insights into the dynamics of subduction. The Andean system, where the Nazca plate plunges beneath continental South America, is commonly regarded as the archetype of this class of tectonics systems. There is distinctive evidence that the degree of mechanical coupling between converging plates, i.e. the amount of resistive force mutually transmitted in the direction opposite to their motions, may be at the present-day significantly higher along the central Andean margin compared to the northern and southern limbs. However quantitative estimates of such resistance are still missing and would be desirable. Here we present laboratory models of subduction performed to investigate quantitatively how strong lateral coupling variations need to be to result in trench curvature, tectonic shortening and distribution of topography comparable to estimates from the Andean margin. The analogue of a two-layers Newtonian lithosphere/upper mantle system is established in a silicone putty/glucose syrup tank-model where lateral coupling variations along the interface between subducting and overriding plates are pre-imposed. Despite the simplicity of our setup, we estimate that coupling in the central margin as large as 20% of the driving force is sufficient to significantly inhibit the ability of the experimental overriding plate to slide above the subducting one. As a consequence, the central margin deforms and shortens more than elsewhere while the trench remains stationary, as opposed to the advancing lateral limbs. This causes the margin to evolve into a peculiar shape similar to the present-day trench of the Andean system.

  17. Coca: The History and Medical Significance of an Ancient Andean Tradition

    Directory of Open Access Journals (Sweden)

    Amy Sue Biondich


    Full Text Available Coca leaf products are an integral part of the lives of the Andean peoples from both a cultural and traditional medicine perspective. Coca is also the whole plant from which cocaine is derived. Coca products are thought to be a panacea for health troubles in regions of South America. This review will examine the toxicology of whole coca and will also look at medicinal applications of this plant, past, present, and future.

  18. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1 There is a critical need for further strategic regional and basin scale evaluation of dams. 2 There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3 Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  19. Antihypertensive and antioxidant activity of atomized andean purple corn (Zea mayz L) hydroalcoholic extract in rats


    Arroyo, Jorge; Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Químico farmaceútico.; Raez, Ernesto; Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Médico patólogo.; Rodríguez, Miguel; Facultad de Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; Chumpitaz, Víctor; Facultad Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; Burga, Jonny; Facultad de Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; De la Cruz, Walter; Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Lima, Perú. Médico.; Valencia, José; Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Lima, Perú. Químico Farmacéutico.


    Objectives. To determine the antihypertensive and antioxidant activity of the atomized hydroalcoholic extract of Zea mays L. (Andean purple corn) in rats with induced hypertension. Material and methods. We used five groups of six Holtzmann rats each, one without hypertension (negative control) and four with hypertension induced by L-NAME: positive control and three groups for the doses of 250, 500 and 1000 mg/kg, respectively. The treatment was carried out orally once a day for 25 days. Th...

  20. Three-dimensional density model of the Nazca plate and the Andean continental margin (United States)

    Tassara, AndréS.; GöTze, Hans-Jürgen; Schmidt, Sabine; Hackney, Ron


    We forward modeled the Bouguer anomaly in a region encompassing the Pacific Ocean (85°W) and the Andean margin (60°W) between northern Peru (5°S) and Patagonia (45°S). The three-dimensional density model that reproduces the gravity field is a continental-scale representation of density structure to 410 km depth that characterizes the mantle and crust of the oceanic Nazca plate, subducted slab and continental margin with a minimum number of bodies. We predefined the density of each body after studying the dependency of density on composition of crustal and mantle materials and pressure-temperature conditions appropriate for the Andean setting. A database of independent geophysical information constrains the geometry of the top of the subducted slab, locally the Moho of the oceanic and continental crusts and, indirectly, the lithosphere-asthenosphere boundary underneath the continental plate. Other boundaries, notably the intracrustal density discontinuity separating upper from lower crust below the continent, were not constrained and their geometry is the result of fitting the observed and calculated Bouguer anomaly during forward modeling. This contribution presents the model to the Andean geoscientific community and contains some tools, like a sensitivity analysis, that helps potential users of the model to interpret its results. We describe and discuss some of these results in order to illustrate the application of the model to the study of a wide range of phenomena (e.g., modification of oceanic plate structure by hot spots, shape of the subducted slab, thermal structure of the continental lithosphere, compensation mechanism and formation of orogenic relieve, causes of Andean segmentation).

  1. Large Differences in Bacterial Community Composition among Three Nearby Extreme Waterbodies of the High Andean Plateau. (United States)

    Aguilar, Pablo; Acosta, Eduardo; Dorador, Cristina; Sommaruga, Ruben


    The high Andean plateau or Altiplano contains different waterbodies that are subjected to extreme fluctuations in abiotic conditions on a daily and an annual scale. The bacterial diversity and community composition of those shallow waterbodies is largely unexplored, particularly, of the ponds embedded within the peatland landscape (i.e., Bofedales). Here we compare the small-scale spatial variability (Altiplano peatland ponds represent a hitherto unknown source of microbial diversity.

  2. Invertebrate metacommunity structure and dynamics in an andean glacial stream network facing climate change

    DEFF Research Database (Denmark)

    Cauvy-Fraunié, Sophie; Espinosa, Rodrigo; Andino, Patricio


    theory as a conceptual framework to better understand how river network structure influences the spatial organization of aquatic communities in glacierized catchments. At 51 stream sites in an Andean glacierized catchment (Ecuador), we sampled benthic macroinvertebrates, measured physico...... community variation. Overland spatial variables based on geographical and altitudinal distances significantly affected community variation. Watercourse spatial variables based on glaciality distances had a unique significant effect on community variation. Within alpine catchment, glacial meltwater affects...

  3. Preliminary phylogenetic analysis of the Andean clade and the placement of new Colombian blueberries (Ericaceae, Vaccinieae

    Directory of Open Access Journals (Sweden)

    Paola Pedraza-Penalosa


    Full Text Available The blueberry tribe Vaccinieae (Ericaceae is particularly diverse in South America and underwent extensive radiation in Colombia where many endemics occur. Recent fieldwork in Colombia has resulted in valuable additions to the phylogeny and as well in the discovery of morphologically noteworthy new species that need to be phylogenetically placed before being named. This is particularly important, as the monophyly of many of the studied genera have not been confirmed. In order to advance our understanding of the relationships within neotropical Vaccinieae and advice the taxonomy of the new blueberry relatives, here we present the most comprehensive phylogenetic analysis for the Andean clade. Anthopterus, Demosthenesia, and Pellegrinia are among the putative Andean genera recovered as monophyletic, while other eight Andean genera were not. The analyses also showed that genera that have been traditionally widely defined are non-monophyletic and could be further split into more discrete groups. Four newly discovered Colombian Vaccinieae are placed in the monophyletic Satyria s.s. and the Psammisia I clade. Although these new species are endemic to the Colombian Western Cordillera and Chocó biogeographic region and three are not known outside of Las Orquídeas National Park, they do not form sister pairs.

  4. Prevalence of the metabolic syndrome in Peruvian Andean hispanics: the PREVENCION study. (United States)

    Medina-Lezama, Josefina; Zea-Diaz, Humberto; Morey-Vargas, Oscar L; Bolaños-Salazar, Juan F; Muñoz-Atahualpa, Edgar; Postigo-MacDowall, Mauricio; Corrales-Medina, Fernando; Valdivia-Ascuña, Zoila; Cuba-Bustinza, Carolina; Paredes-Díaz, Sheyla; Villalobos-Tapia, Paola; Chirinos-Pacheco, Julio; Goldberg, Ronald B; Chirinos, Julio A


    Data regarding the prevalence of metabolic syndrome (MTS) in Andean populations are limited. We evaluated the prevalence of MTS according to American Heart Association/National Heart, Lung and Blood Institute criteria among 1878 subjects in the PREVENCION study in Peru. In women, the most common component was low HDL cholesterol (60.9%) followed by abdominal obesity (36.9%). In men, the most common component was elevated triglycerides (52.0%) followed by low HDL cholesterol (32.5%), whereas the prevalence of abdominal obesity was 14%. Abnormal fasting glucose was the least common component in men (5.4%) and women (5.0%). The prevalence of MTS was significantly higher in women compared to men (23.2% versus 14.3%) and increased steeply with age, particularly in women (por=30kg/m2) instead of waist circumference as a component of the MTS lead to equivalent prevalence estimates of MTS in men but significantly underestimated the prevalence in women. The MTS is highly prevalent among Peruvian Andeans, particularly in older women. The pattern of MTS components in this Andean population is characterized by a high prevalence of dyslipidemia and a relatively low prevalence of elevated fasting glucose. Further studies are required to characterize genetic and environmental determinants of these patterns.

  5. Estimating Aboveground Biomass and Carbon Stocks in Periurban Andean Secondary Forests Using Very High Resolution Imagery

    Directory of Open Access Journals (Sweden)

    Nicola Clerici


    Full Text Available Periurban forests are key to offsetting anthropogenic carbon emissions, but they are under constant threat from urbanization. In particular, secondary Neotropical forest types in Andean periurban areas have a high potential to store carbon, but are currently poorly characterized. To address this lack of information, we developed a method to estimate periurban aboveground biomass (AGB—a proxy for multiple ecosystem services—of secondary Andean forests near Bogotá, Colombia, based on very high resolution (VHR GeoEye-1, Pleiades-1A imagery and field-measured plot data. Specifically, we tested a series of different pre-processing workflows to derive six vegetation indices that were regressed against in situ estimates of AGB. Overall, the coupling of linear models and the Ratio Vegetation Index produced the most satisfactory results. Atmospheric and topographic correction proved to be key in improving model fit, especially in high aerosol and rugged terrain such as the Andes. Methods and findings provide baseline AGB and carbon stock information for little studied periurban Andean secondary forests. The methodological approach can also be used for integrating limited forest monitoring plot AGB data with very high resolution imagery for cost-effective modelling of ecosystem service provision from forests, monitoring reforestation and forest cover change, and for carbon offset assessments.

  6. [Diversity and dynamics of a high sub-Andean forest from Northern Andes, Colombia]. (United States)

    Restrepo, Jesús Oswaldo Velásquez; Maniguaje, Nancy Lorena; Duque, Alvaro Javier


    The sub-Andean forests are characterized by a high biodiversity, but little is known about their natural dynamics. In order to generate new information, this study assessed two permanent plots of one hectare each, in the Northern Andean area of the Western Cordillera, Colombia. Methodology included the evaluation of diversity patterns, above ground biomass (AGB) dynamics, and mortality and recruitment rates. Besides, we used the Fisher's Alpha index to calculate species diversity. Forest dynamics and AGB were evaluated in both plots by means of three censuses carried out within a nine years period. In total, we found 1 664 individuals with diameter at breast height (DBH)> or =10cm belonging to 222 species, 113 genera and 60 families. Mean species richness was of 156 species/ha and a mean Fisher's Alpha index of 56.2/ha. The mortality rate was 0.88% and recruitment was 1.16%, which did not allow to lay any external effect of global warming or climate change on individual forest dynamics. However, the mean AGB was 243.44+/-9.82t/ha, with an annual average increase of 2.9t/ha, a higher value than the one reported in other studies of high sub-Andean forests, which suggests that equilibrium in terms of the AGB have not yet been reached. Besides, according to field observations, a recovery process, from a disturbance that occurred in the past, might be on his way.

  7. Andean uplift promotes lowland speciation through vicariance and dispersal in Dendrocincla woodcreepers. (United States)

    Weir, Jason T; Price, Momoko


    Andean uplift contributed importantly to the build-up of high Neotropical diversity. Final uplift of the Eastern Cordillera of Colombia separated once-contiguous lowland faunas east and west of the Andes between 5 and 3.5 million years ago (Ma hereafter). We used DNA sequences from several moderate- to fast-evolving mitochondrial and two slow-evolving nuclear genes to generate a well-supported phylogeny of Dendrocincla woodcreepers, a genus with multiple species endemic to lowland regions both east and west of the Andes. A time-calibrated phylogeny and dispersal-vicariance analysis indicated that uplift of the Eastern Cordillera of Colombia resulted in the initial vicariant separation of a widespread lowland form east and west of the Andes at c. 3.6 Ma. This was followed by two separate east-to-west dispersal events over or around the completed Andes, each producing a genetically distinct lineage. Our analysis suggests that Andean uplift promoted the build-up of biodiversity in lowland Neotropical faunas both through vicariance-based speciation during uplift and through dispersal-based speciation following uplift. In contrast to the multiple colonizations of the trans-Andean region by Dendrocincla, the Atlantic Forest was colonized from the Amazon only once, followed by in situ diversification.

  8. Introduction and Establishment of Pissodes castaneus (Coleoptera: Curculionidae) in the Andean Patagonia of Argentina. (United States)

    Pereyra, V A; Gomez, C A; La Manna, L; Roux, G; Lanteri, A A; Vallejos, N C; Marvaldi, A E


    The pine weevils that occur in plantations of Pinus spp. in Andean Patagonia of Argentina belong to the species Pissodes castaneus (De Geer), a Eurasian endemic species, according to the identification based on molecular and morphological characters. Sequences of the mitochondrial Cytochrome oxidase subunit I and nuclear genes (28 S rDNA and ITS2) were obtained for individuals of 13 afforestations, covering the entire distribution area of the established populations in the Andean Patagonia of Argentina. Sequence comparison with representative species of the genus (European, North American, and Chinese species) shows that Patagonian specimens are conspecific to those of P. castaneus sequenced from Europe. Phylogenetic analyses indicate that all terminals from Patagonia form a monophyletic unit without evident subclades, eliminating the possibility of existence of more than one species of Pissodes Germar in this area, including cryptic ones. Moreover, the very low genetic divergence between the Patagonian populations suggests that it is plausible that P. castaneus was introduced into Patagonia from just one location. Mitochondrial DNA analysis shows that Patagonian terminals group together with a French haplotype and are clearly separated from other P. castaneus individuals represented in our sample, and reveal that established populations in Andean Patagonia originated via a limited introduction.

  9. Agronomic performance and stability of andean common bean lines with white grains in Brazil

    Directory of Open Access Journals (Sweden)

    Helton Santos Pereira


    Full Text Available This work evaluated the effect of genotype by environment interaction in Andean common bean lines with white grains, in Central Southern Brazil, to identify lines with high agronomic performance, stability and adaptability, aiming to meet domestic demand and to increase the Brazilian participation in the foreign market of common bean. Nineteen trials with twelve Andean lines were conducted in 2007, 2008 and 2009, in Central Southern Brazil. Grain yield and other agronomic traits were evaluated. Data were subjected to analysis of variance and of adaptability/stability using Annicchiarico and modified AMMI methods. Significant differences were found between lines for all traits evaluated. Genotype by environment interaction was important for lines with Andean origin and white seed. The utilization of weighted mean of absolute scores and yield with the AMMI results enabled the identification of the most stable and adapted lines. Lines Poroto Alubia, CNFB 16211, Ouro Branco and WAF 160 were stable and adapted, using both methods. CNFB 16211 line presented high agronomic performance, stability and adaptability and therefore this line may be a new cultivar. USWA 70 and WAF 75 lines presented grain size similar to that required by the foreign market and superior to the Brazilian cultivars, besides favorable agronomic traits, and thus these lines may be indicated as new cultivars.

  10. A regional perspective on the diversity and conservation of tropical Andean fishes. (United States)

    Anderson, Elizabeth P; Maldonado-Ocampo, Javier A


    The tropical Andes harbor an extraordinarily varied concentration of species in a landscape under increasing pressure from human activities. Conservation of the region's native plants and animals has received considerable international attention, but the focus has been on terrestrial biota. The conservation of freshwater fauna, particularly the conservation of fishes, has not been emphasized. Tropical Andean fishes are among the most understudied vertebrates in the world. We estimate that between 400 and 600 fish species inhabit the diverse aquatic environments in the region. Nearly 40% of these species are endemic. Tropical Andean fishes are vulnerable to ongoing environmental changes related to deforestation, water withdrawals, water pollution, species introductions, and hydropower development. Additionally, their distributions and population dynamics may be affected by hydrologic alterations and warmer water temperatures associated with projected climate change. Presently, at least three species are considered extinct, some populations are endangered, and some species are likely to decline or disappear. The long-term persistence of tropical Andean fishes will depend on greater consideration of freshwater systems in regional conservation initiatives.

  11. Re-Os geochronology of the El Salvador porphyry Cu-Mo deposit, Chile: Tracking analytical improvements in accuracy and precision over the past decade (United States)

    Zimmerman, Aaron; Stein, Holly J.; Morgan, John W.; Markey, Richard J.; Watanabe, Yasushi


    Sulfide minerals from the El Salvador porphyry Cu-Mo deposit, Chile, were dated by Re-Os geochronology to clarify the timing and duration of mineralization. As these data are collected over the past 10 years, they chronicle the evolution of Re-Os analytical procedures and improvements in spike-sample equilibration, mass spectrometry and data reduction. Included in the data is the first tennantite-pyrite Re-Os isochron along with tennantite-enargite-pyrite Os tracing of ore metals based on initial osmium systematics (187Os/188Osi). Porphyry-associated mineralization follows the traditional early (A), transitional (B), and late (D) stage classification of relative timing of vein formation. Most Cu- and Mo-bearing sulfides were deposited during stages A and B. Field relationships clearly show the B-stage veins are older than the D-stage veins. Samples analyzed with Carius tube digestion and mixed-double spike indicate B-stage molybdenite mineralization between 41.8 and 41.2 Ma. These ages best represent the timing of main-stage mineralization at El Salvador. A five-point 187Re-187Os isochron for pyrite-tennantite from the latest D-stage veins yields an age of 42.37 ± 0.45 Ma. The isochron age, while older, is within error of early analyses of molybdenite by alkaline fusion digestion using single Re and Os spikes (42.4-42.0 Ma). A separate pyrite and tennantite-enargite pair containing significant common Os yields an initial 187Os/188Os ratio of 0.134 ± 0.042, compatible with a predominantly mantle origin. We appreciate the early analyses for their historical significance while emphasize the geological implications of the 41.8-41.2 Ma molybdenite ages. Temperature estimates by sulfur thermometry and fluid inclusions are 390-510 °C for the B-stage molybdenites and 230-240 °C for the latest D-stage pyrite and tennantite. Analyses based on Carius tube digestion and updated spike calibrations suggest a ∼0.6 m.y. duration (∼41.8 to 41.2 Ma) in-line with published

  12. Distribution of Lutzomyia ayacuchensis, the vector of Andean-type cutaneous leishmaniasis, at different altitudes on the Andean slope of Ecuador. (United States)

    Gomez, Eduardo A; Kato, Hirotomo; Mimori, Tatsuyuki; Hashiguchi, Yoshihisa


    Distribution of the vector species is a major risk factor for the endemicity of leishmaniasis. In the present study, the vertical distribution of Lutzomyia (Lu.) ayacuchensis, the vector of Leishmania (Leishmania) mexicana in the Ecuadorian Andes, was surveyed at different altitudes (300-2500m above sea level) of the Andean slope. The vector species Lu. ayacuchensis was identified at an altitude of 650m and a higher areas, and higher distribution ratio of the species was observed at higher altitudes. In addition, high ratios of L. (L.) mexicana infection were detected in higher areas, but none in lower populations of sand flies. Since an association between sand fly populations and vector competence is suggested in Lu. ayacuchensis, haplotype analysis was performed on the species from different altitudes of the study areas; however, no apparent difference was observed among populations. These results suggested that Lu. ayacuchensis in Andean slope areas of Ecuador has the potential to transmit L. (L.) mexicana and spread leishmaniasis in these areas.

  13. Study on the origin of the Hongshan brecciated copper deposit in Huichang County,Jiangxi Province, China

    Institute of Scientific and Technical Information of China (English)


    The Hongshan copper deposit is a typical cryptoexplosive breccia-type deposit, which occurs in a Metamorphic rock series of the Mesoproterozoic Taoxiyuan Formation. Orebodies are distributed inside and outside porphyry-cryptoexplosive breccia pipes. The isotope geochemistry of the deposit is consistent with the origin of porphyry breccia: the δ18OH2O values ranging from 1.2‰ to 6.1‰ and the δ34S values varying from 0 to 2.5‰.206Pb/204Pb,207Pb/204Pb and 208Pb/204Pb ratios of pyrite, which coexists with ore minerals, indicate it was derived from the orogenic belt. Thermodynamic analysis indicates that the main metals were deposited largely as a result of the decreasing of proton concentrations associated with H2S and CO2 exsolution during exploslon and temperature dropping.Based on K-Ar dating of quartz coexisting with ore minerals,the age of mineralization was estimated to be 97.1-98.8 Ma,which suggests that mineralization occurred between the Early and Late Cretaceous. According to the relevant informtion obtained,a diagenetic and metallogenic pattern in the area has been presented in this paper.

  14. Sr and O isotopic characteristics of porphyries in the Qinling molybdenum deposit belt and their implication to genetic mechanism and type

    Institute of Scientific and Technical Information of China (English)

    陈衍景; 李超; 张静; 李震; 王海华


    A great deal of Mesozoic hypobatholithic granites and hypabyssal porphyries develop in the Qinling Mountains. The former has long been regarded as transformation type (or S-type), and the latter associated with Mo-mineralization regarded as syntexis type (or l-type) granitoids. Statistics show that Sr, andδ18O of hypabyssal porphyries respectively range from 0.705 to 0.714, and from 7.2‰ to 12.1‰, agreeing with those of hypobatholithes (Sr1=0.705-0.710, δ18O = 6.1‰-10.4‰), which indicates that they share similar material sources and petrogenic mechanism. Based on analysis of lithological, mineralogical and geochemical characteristics of these granitoids and on study of their petrogenic tectonic background and regional geophysical data, we argue that both the shallow-seated porphyries and deep-seated batholithes were the products of Mesozoic collision between South China and North China paleocontinents. Subsequently, all these granti-toids should be attributed to collision type.

  15. Mineralogy, textures, and whole-rock geochemistry of advanced argillic alteration: Hugo Dummett porphyry Cu-Au deposit, Oyu Tolgoi mineral district, Mongolia (United States)

    Khashgerel, Bat-Erdene; Kavalieris, Imants; Hayashi, Ken-Ichiro


    Advanced argillic (AA) alteration is developed over a vertical interval of 500 m, above (and enclosing) Late Devonian quartz monzodiorite intrusions that accompany porphyry-style Cu-Au mineralization at the Hugo Dummett deposit. The AA alteration is mainly in basaltic rocks and locally extends into the overlying dacitic ash-flow tuff for about 100 m. The AA zone overprints porphyry-style quartz veins associated with quartz monzodiorite intrusions, but at least partly precedes high-grade porphyry-style bornite mineralization. Mineralogically, it consists of andalusite, corundum, residual quartz, titanium oxides, diaspore, alunite, aluminum phosphate-sulfate (APS) minerals, zunyite, pyrophyllite, topaz, kaolinite, and dickite, as well as anhydrite and gypsum, but is dominated by residual quartz and pyrophyllite. Alteration zonation is not apparent, except for an alunite-bearing zone that occurs approximately at the limit of strong quartz veining. Whole-rock geochemistry shows that the AA alteration removes most major elements except Si, Al, Ti, and P, and removes the trace elements Sc, Cs, and Rb. V, Zr, Hf, Nb, Ta, U, and Th are relatively immobile, whilst light REEs (La to Nd), Sr, Ba, and Ga can be enriched. Middle REEs (Sm to Gd) are moderately depleted; Y and heavy REEs (Tb to Lu) are strongly depleted except in two unusual samples where middle to heavy REEs are enriched.

  16. Handling of Copper and Copper Oxide Nanoparticles by Astrocytes. (United States)

    Bulcke, Felix; Dringen, Ralf


    Copper is an essential trace element for many important cellular functions. However, excess of copper can impair cellular functions by copper-induced oxidative stress. In brain, astrocytes are considered to play a prominent role in the copper homeostasis. In this short review we summarise the current knowledge on the molecular mechanisms which are involved in the handling of copper by astrocytes. Cultured astrocytes efficiently take up copper ions predominantly by the copper transporter Ctr1 and the divalent metal transporter DMT1. In addition, copper oxide nanoparticles are rapidly accumulated by astrocytes via endocytosis. Cultured astrocytes tolerate moderate increases in intracellular copper contents very well. However, if a given threshold of cellular copper content is exceeded after exposure to copper, accelerated production of reactive oxygen species and compromised cell viability are observed. Upon exposure to sub-toxic concentrations of copper ions or copper oxide nanoparticles, astrocytes increase their copper storage capacity by upregulating the cellular contents of glutathione and metallothioneins. In addition, cultured astrocytes have the capacity to export copper ions which is likely to involve the copper ATPase 7A. The ability of astrocytes to efficiently accumulate, store and export copper ions suggests that astrocytes have a key role in the distribution of copper in brain. Impairment of this astrocytic function may be involved in diseases which are connected with disturbances in brain copper metabolism.

  17. Soil organic matter dynamics at the paramo and puna highlands in the Andean mountains (United States)

    Ángeles Muñoz, M.; Faz, Ángel; Mermut, Ahmet R.; Zornoza, Raúl


    Mountains and uplands represent the most diverse and fragile ecosystems in the world, cover about 20% of the terrestrial surface and are distributed across all continents and major ecoregions. The Andean Plateau is the main mountain range of the American continent and one of the largest in the world with more than 7,500 km. The soil organic matter is a corner stone in the fertility management of the Andean agriculture as well as in the erosion control. However, its role is still much unknown in these ecosystems. Moreover, the influence of current global climatic change on soil organic C reservoirs and dynamics is still not clearly understood. The aim of this work was to review the soil C dynamics and the implication of the soil organic matter in the fertility management, erosion control, conservation of biodiversity and global climate change to improve the knowledge on the mountain Andean highlands. Climate, landscape, soil C pools, biomass and management were studied. In general, the Andean climate is affected by three main factors: ocean currents, winds and orography characterized by an abrupt topography. The entire Andean belt is segmented into the Northern, Central and Southern Andes. Northern Andes are called paramo and are characterized by humid climate while Central and Southern Andes dryer zones are called puna. Most of the region is tectonically and volcanically active. Sedimentary rocks predominated in the paramo while sedimentary, igneous and metamorphic ones prevailed in the puna. The most common soils were Andosols, Regosols, Umbrisols and Histosols. The cold and wet climate and the low atmospheric pressure favored organic matter accumulation in the soil. The accumulation of organic matter is further enhanced by the formation of organomineral complexes strongly resistant to the microbial breakdown mainly in the paramo. High organic C contents were observed in the paramo (10%) oppositely to the low contents found in the dryer puna (1%). The C/N ratio

  18. Canine models of copper toxicosis for understanding mammalian copper metabolism


    Fieten, Hille; Leegwater, Peter A. J.; Watson, Adrian L.; Rothuizen, Jan


    Hereditary forms of copper toxicosis exist in man and dogs. In man, Wilson’s disease is the best studied disorder of copper overload, resulting from mutations in the gene coding for the copper transporter ATP7B. Forms of copper toxicosis for which no causal gene is known yet are recognized as well, often in young children. Although advances have been made in unraveling the genetic background of disorders of copper metabolism in man, many questions regarding disease mechanisms and copper homeo...

  19. Hair copper in intrauterine copper device users. (United States)

    Thiery, M; Heyndrickx, A; Uyttersprot, C


    The antifertility effect of copper-bearing IUDs is based on continuous release of copper, which is a result of the reaction between the metal and the uterine secretions. Released cupric ions collect in the endometrium and in the uterine fluid but significant accumulation has not been found in the bloodstream or elsewhere. Following Laker's suggestion that hair be used for monitoring essential trace elements, e.g., copper, we checked the copper content of the hair of women wearing copper-bearing IUDs. Samples of untreated pubic hair removed by clipping before diagnostic curettage were obtained from 10 young (24-34 years old), white caucasian females who until then had been wearing an MLCu250 IUD for more than 1 year. Pubes from 10 comparable (sex, age, race) subjects who had never used a Cu-containing device served as controls. The unwashed material was submitted to the toxicology laboratory, where the copper content was assessed by flameless atomic absorption, a technique whose lower limit of measurement lies at a concentration of 0.05 mcg Cu/ml fluid (50 ppb). Hair samples were washed to remove extraneous traces of metal according to the prescriptions of the International Atomic Energy Agency, weighed, and mineralized, after which a small volume (10 mcl) of the diluted fluid was fed into the graphite furnace. Each sample (75-150 mg) was analyzed 4 times, both before and after washing. Since the cleaning procedure reduces the weight of the sample (mainly by the removal of fat, dust, etc.) this explains why the percentage copper content of washed hair is higher than that of unwashed hair belonging to the same subject. The results indicate that there was no significant difference (Mann-Whitney U test) between the mean copper levels of both unwashed and washed pubes from women who were using or had never used an MLCu250 IUD. We therefore conclude that the use of this copper-containing device is not associated with significant accumulation of copper in (pubic) hair.

  20. Biogenic nanoparticles: copper, copper oxides, copper sulphides, complex copper nanostructures and their applications. (United States)

    Rubilar, Olga; Rai, Mahendra; Tortella, Gonzalo; Diez, Maria Cristina; Seabra, Amedea B; Durán, Nelson


    Copper nanoparticles have been the focus of intensive study due to their potential applications in diverse fields including biomedicine, electronics, and optics. Copper-based nanostructured materials have been used in conductive films, lubrification, nanofluids, catalysis, and also as potent antimicrobial agent. The biogenic synthesis of metallic nanostructured nanoparticles is considered to be a green and eco-friendly technology since neither harmful chemicals nor high temperatures are involved in the process. The present review discusses the synthesis of copper nanostructured nanoparticles by bacteria, fungi, and plant extracts, showing that biogenic synthesis is an economically feasible, simple and non-polluting process. Applications for biogenic copper nanoparticles are also discussed.

  1. China Copper Processing Industry Focus

    Institute of Scientific and Technical Information of China (English)


    <正>1. Market Consumption The ’China Factor’ and Copper Price Fluctuation We all know China is an enormous consumer of copper,but the exact levels of consumption and where the copper has gone remains a mystery.

  2. Constraints on the origin and evolution of magmas in the Payún Matrú Volcanic Field, Quaternary Andean Back-arc of Western Argentina

    NARCIS (Netherlands)

    Hernando, I.R.; Aragón, E.; Frei, R.; González, P.D.; Spakman, W.


    The Payún Matrú Volcanic Field (Pleistocene–Holocene) is located in the Andean back-arc of the Southern Volcanic Zone, western Argentina, and is contemporaneous with the Andean volcanic arc at the same latitude. It includes two polygenetic, mostly trachytic volcanoes: Payún Matrú (with a summit cald

  3. 'Andean-centred' genera in the short-branch clade of Annonaceae: testing biogeographical hypotheses using phylogeny reconstruction and molecular dating

    NARCIS (Netherlands)

    Pirie, M.D.; Chatrou, L.W.; Mols, J.B.; Erkens, R.H.J.; Oosterhof, J.


    Aim We test biogeographical hypotheses regarding the origin of Andean-centred plant groups by reconstructing phylogeny in the short-branch clade (SBC) of Annonaceae, and estimating the timing of diversifications in four apparently Andean-centred genera: Cremastosperma R.E.Fr., Klarobelia Chatrou, Ma

  4. Natural or Artificial? Multi-Analytical Study of a Scagliola from Estoi Palace Simulating Imperial Red Porphyry. (United States)

    Freire, Maria Teresa; Santos Silva, António; Veiga, Maria do Rosário; Brito, Jorge de; Schlütter, Frank


    In this paper the characterization of a gypsum plaster sample from the end of the 19th century simulating imperial red porphyry using a multi-analytical approach is presented and discussed. The results of X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TGA-DTA), physical and mechanical properties are summarized. In order to have further insight into the microstructure, polarized light microscopy (PLM), scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDS), and micro Raman spectroscopy analyzes were also made. They helped to clarify the main issues raised by the other complementary analytical techniques and allowed the establishment of interrelations between the different properties, providing important information about the materials, the skills, and the technological development involved in the art of imitating noble stones with gypsum pastes. This study also contributes to our knowledge concerning the preservation of these types of elements that are important in the context of European decorative arts and rarely reported in the literature.

  5. Zircon U–Pb geochronology and geochemistry of rhyolitic tuff, granite porphyry and syenogranite in the Lengshuikeng ore district, SE China: Implications for a continental arc to intra-arc rift setting

    Indian Academy of Sciences (India)

    Changming Wang; Da Zhang; Ganguo Wu; Yigan Xu; Emmanuel John M Carranza; Yaoyao Zhang; Huaikun Li; Jianzhen Geng


    SE China is well known for its Mesozoic large-scale granitoid plutons and associated ore deposits. Here, zircon U–Pb geochronological and geochemical data have been used to better constrain the petrogenesis of the igneous rocks associated with porphyry Ag–Pb–Zn deposits in the Lengshuikeng ore district, SE China. The Lengshuikeng rhyolitic tuff, granite porphyry and syenogranite yielded zircon U–Pb ages of 161, 155 and 138 Ma, respectively. The Lengshuikeng granite porphyries belong to calc-alkaline series and show fractionated I-type affinities. The rhyolitic tuffs show almost similar characteristics as the granite porphyries. The engshuikeng syenogranites are all alkali-rich and show A-type affinities. The syenogranites have high contents of high field strength elements such as Nb, Ta, Zr, Hf; with Zr + Nb + Ce + Y contents of < 350 ppm. Chondrite-normalized REE patterns show relative enrichment of LREEs and strong negative Eu anomalies. The Lengshuikeng granite porphyries, syenogranites and tuffs were probably derived from partial melting of underlying Proterozoic metasedimentary rocks with minor addition of mantle-derived magmas, accompanied by fractional crystallization. Detailed petrologic and geochemical data for the Jurassic igneous rocks from the Lengshuikeng ore district imply that during the Late Jurassic, SE China on the southeast of the Shi-Hang zone was a continental arc associated with the subduction of the Palaeo-Pacific plate and that since the beginning of the Early Cretaceous an intra-arc rift has been formed along the Shi-Hang zone.

  6. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M


    Copper and Silver Halates is the third in a series of four volumes on inorganic metal halates. This volume presents critical evaluations and compilations for halate solubilities of the Group II metals. The solubility data included in this volume are those for the five compounds, copper chlorate and iodate, and silver chlorate, bromate and iodate.

  7. Coping with copper

    DEFF Research Database (Denmark)

    Nunes, Ines; Jacquiod, Samuel; Brejnrod, Asker


    Copper has been intensively used in industry and agriculture since mid-18(th) century and is currently accumulating in soils. We investigated the diversity of potential active bacteria by 16S rRNA gene transcript amplicon sequencing in a temperate grassland soil subjected to century-long exposure......, suggesting a potential promising role as bioindicators of copper contamination in soils....

  8. Lithogeochemistry and Sr-Nd-Pb Isotopic Characteristics of Mujicun Porphyry Cu-Mo Deposit in Taihang Mountains and Their Significances%太行山木吉村斑岩铜(钼)矿床岩石地球化学、S r-Nd-Pb同位素特征及其地质意义

    Institute of Scientific and Technical Information of China (English)

    曲凯; 董国臣; 李胜荣; 申俊峰; 王艳娟; 王霞; 罗薇


    Mujicun porphyry copper-molybdenum deposit, located in the northern section of Taihang Mountains,is an important ore deposit in the Taihang tectonic-magmatic-metallogenic belt.This article is based on the particular field works and systematic analysis of petrology,geochemical data and Sr-Nd-Pb isotopes.The result shows the ore-bearing diorite-porphyry of Mujicun belonging to the high-K calc-alkaline I-type intrusive rock.Geochemical analysis shows that the diorite-porphyry is rich in SiO2,Al2O3 and Sr,a high ratio of Sr/Y, (La/Yb)N ,low in Yb and Y.All the ore-bearing porphyries in the study area have similar distribution of rare earths and trace elements,with right-oblique curve,and unclear postive Eu anomalies.It is characterized by enriched large-ion lithophile elements of Ba,K,U,Sr and depleted high field strength elements such as Nb, Ta,P and Ti with adakite affinity in geochemical characteristic.The diorite porphyry has ISr ratios of 0.705 386 to 0.706 838,εNd(t)values of -16.7 to -14.9.The averages of 208Pb/204Pb,207Pb/204Pb and 206Pb/204Pb ratios are 36.614,15.226 and 16.545,respectively,similar to those lead isotope ratios in ore of Mujicun de-posit.Sr-Nd-Pb isotopes show that the formations of the magma were probably related to origin of partial melting of lower crust with mantle materials contribution.Combining with the geological background of the study area, the authors considered that the Mujicun ore-bearing diorite porphyry possibly resulted from partial melting in lower crust with the mantle mass exchange.%木吉村斑岩铜(钼)矿床位于太行山北段涞源杂岩体的腰部,是太行山构造-岩浆-成矿带的一个重要矿床。在野外调研的基础上,对木吉村斑岩铜(钼)矿床含矿岩体进行了系统的岩石学、地球化学和Sr-Nd-Pb同位素研究。结果表明:木吉村矿床的含矿岩体闪长玢岩为高钾钙碱性I型侵入岩,具有较高的SiO2、Al2 O3、Sr含量

  9. Genetic control of the seed coat colour of Middle American and Andean bean seeds. (United States)

    Possobom, Micheli Thaise Della Flora; Ribeiro, Nerinéia Dalfollo; Zemolin, Allan Emanoel Mezzomo; Arns, Fernanda Daltrozo


    Seed coat colour of bean seeds is decisive for acceptance of a cultivar. The objectives of this research were to determine whether there is maternal effect for "L", a* and b* colour parameters in Middle American and Andean bean seeds; to obtain estimates of heritability and gain with selection for "L", a* and b* values; and select recombinants with the seed coat colour required by the market demand. Thus, controlled crossings were carried out between the Middle American lines CNFP 10104 and CHC 01-175, and between the Andean lines Cal 96 and Hooter, for obtaining F1, F1 reciprocal, F2 and F2 reciprocal generations for each hybrid combination. Parents and generations were evaluated in two field experiments (2012 normal rainy and 2013 dry seasons) in the state of Rio Grande do Sul, Brazil. Seed coat colour was quantified with a portable colorimeter. Genetic variability for "L" (luminosity), chromaticity a* (green to red shade), and chromaticity b* (blue to yellow shade) values was observed in seeds with F2 seed coat of Middle American and Andean beans. "L", a* and b* values in bean seeds presented maternal effects. High broad-sense heritability are observed for luminosity (h(2)b: 76.66-95.07%), chromaticity a* (h(2)b: 73.08-89.31%), and chromaticity b* (h(2)b: 88.63-92.50%) values in bean seeds. From the crossings, it was possible to select bean seeds in early generation for the black group, and for carioca and cranberry types (dark or clear background) which present the colour required by the market demand.

  10. Identifying positive selection candidate loci for high-altitude adaptation in Andean populations

    Directory of Open Access Journals (Sweden)

    Bigham Abigail W


    Full Text Available Abstract High-altitude environments (>2,500 m provide scientists with a natural laboratory to study the physiological and genetic effects of low ambient oxygen tension on human populations. One approach to understanding how life at high altitude has affected human metabolism is to survey genome-wide datasets for signatures of natural selection. In this work, we report on a study to identify selection-nominated candidate genes involved in adaptation to hypoxia in one highland group, Andeans from the South American Altiplano. We analysed dense microarray genotype data using four test statistics that detect departures from neutrality. Using a candidate gene, single nucleotide polymorphism-based approach, we identified genes exhibiting preliminary evidence of recent genetic adaptation in this population. These included genes that are part of the hypoxia-inducible transcription factor (HIF pathway, a biochemical pathway involved in oxygen homeostasis, as well as three other genomic regions previously not known to be associated with high-altitude phenotypes. In addition to identifying selection-nominated candidate genes, we also tested whether the HIF pathway shows evidence of natural selection. Our results indicate that the genes of this biochemical pathway as a group show no evidence of having evolved in response to hypoxia in Andeans. Results from particular HIF-targeted genes, however, suggest that genes in this pathway could play a role in Andean adaptation to high altitude, even if the pathway as a whole does not show higher relative rates of evolution. These data suggest a genetic role in high-altitude adaptation and provide a basis for genotype/phenotype association studies that are necessary to confirm the role of putative natural selection candidate genes and gene regions in adaptation to altitude.

  11. Prevalence and patterns of hypertension in Peruvian Andean Hispanics: the PREVENCION study. (United States)

    Medina-Lezama, Josefina; Zea-Diaz, Humberto; Morey-Vargas, Oscar L; Bolaños-Salazar, Juan F; Postigo-Macdowall, Mauricio; Paredes-Díaz, Sheyla; Corrales-Medina, Fernando; Valdivia-Ascuña, Zoila; Cuba-Bustinza, Carolina; Villalobos-Tapia, Paola; Muñoz-Atahualpa, Edgar; Chirinos-Pacheco, Julio; Raij, Leopoldo; Chirinos, Julio A


    Cardiovascular disease is emerging as a leading cause of morbidity and mortality in Latin America. Population-based data regarding the prevalence of hypertension and hypertension subtypes in Andean Hispanic populations are scarce. The authors performed a population-based study that included 1878 Peruvian Andean adults to determine: (1) the prevalence, awareness, and control of hypertension and (2) the relative frequency of hypertension subtypes (systolic vs. diastolic). The prevalence of hypertension was 15.7% (95% confidence interval [CI], 14.0%-17.4%), did not differ by gender, and increased steeply with age, particularly in women. Awareness, treatment, and control rates were 47.9%, 39.5%, and 14%, respectively. Diastolic blood pressure increased until age 50 years and reached a plateau thereafter, whereas mean arterial pressure continued to increase with age even after age 50 years. Furthermore, in sharp contrast with the United States population, the predominant type of hypertension was systodiastolic (41.7%; 95% CI, 35.1%-48.5%). Isolated systolic hypertension accounted for only 29.3% of cases (95% CI, 23.9%-35.4%) and was responsible for a minority of cases in all age groups before age 70 years. Hypertension subtypes in this Andean population seem to differ significantly from those present in the United States population, with a much larger proportion of systodiastolic and diastolic hypertension even with advanced age. These differences result from interactions between hemodynamic and structural factors, and further studies aimed at characterizing their genetic and environmental determinants and implications in end-organ damage and prognosis in this population may contribute to understanding the pathophysiology of hypertension.

  12. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams? (United States)

    Iñiguez-Armijos, Carlos; Leiva, Adrián; Frede, Hans-Georg; Hampel, Henrietta; Breuer, Lutz


    Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices) and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS), we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%). Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.

  13. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams?

    Directory of Open Access Journals (Sweden)

    Carlos Iñiguez-Armijos

    Full Text Available Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS, we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%. Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.

  14. Analysis of the drought resilience of Andosols on southern Ecuadorian Andean páramos

    Directory of Open Access Journals (Sweden)

    V. Iñiguez


    Full Text Available The neotropical Andean grasslands above 3500 m a.s.l. known as "páramo" offer remarkable ecological services for the Andean region. Most important is the water supply – of excellent quality – to many cities and villages established in the lowlands of the inter-Andean valleys and to the coast. However, the páramo ecosystem is under constant and increased threat by human activities and climate change. In this paper we study the resilience of its soils for drought periods during the period 2007–2013. In addition, field measurements and hydrological conceptual modelling at the catchment-scale are comparing two contrasting catchments in the southern Ecuadorian Andes. Both were intensively monitored during two and a half years (2010–2012 in order to analyse the temporal variability of the soil moisture storage. A typical catchment on the páramo at 3500 m a.s.l. was compared to a lower grassland one at 2600 m a.s.l. The main aim was to estimate the resilience capacity of the soils during a drought period and the recovery during a subsequent wet period. Local soil water content measurements in the top soil (first 30 cm through TDR were used as a proxy for the catchment's average soil moisture storage. The local measurements were compared to the average soil water storage as estimated by the probabilistic soil moisture (PDM model. This conceptual hydrological model with 5 parameters was calibrated and validated for both catchments. The study reveals the extraordinary resilience capacity of this type of shallow organic soils during the droughts in 2009 and 2010. During these droughts, the soil water content dropped from a normal value of about 0.80 to ~ 0.60 cm3 cm−3, while the recovery time was only two to three months.

  15. Plasma soluble erythropoietin receptor is decreased during sleep in Andean highlanders with Chronic Mountain Sickness


    Villafuerte, Francisco C.; Corante, Noemí; Anza-Ramírez, Cecilia; Figueroa-Mujíca, Rómulo; Vizcardo-Galindo, Gustavo; Mercado, Andy; Macarlupú, José Luis; León-Velarde, Fabiola


    Excessive erythrocytosis (EE) is the main sign of Chronic Mountain Sickness (CMS), a highly prevalent syndrome in Andean highlanders. Low pulse O2 saturation (SpO2) during sleep and serum androgens have been suggested to contribute to EE in CMS patients. However, whether these factors have a significant impact on the erythropoietin (Epo) system leading to EE is still unclear. We have recently shown that morning soluble Epo receptor (sEpoR), an endogenous Epo antagonist, is decreased in CMS pa...

  16. Physics in the Andean Countries: A Perspective from Condensed Matter, Novel Materials and Nanotechnology (United States)

    Prieto, P.


    We will discuss the current state of R&D in the fields of condensed matter, novel materials, and nanotechnology in the Andean nations. We will initially consider Latin America and the Caribbean (LAC) to then visualize individual developments, as well as those for the region as a whole in these fields of knowledge in each of the nations constituting the Andean Region (Bolivia, Ecuador, Chile, Venezuela, Peru, and Colombia). Based on Science & Technology watch exercises in the countries involved, along with the Iberian American and Inter-American Science & Technology Network of Indicators (Red de indicadores de Ciencia y Tecnolog'ia (RICYT) iberoamericana e interamericana)1, we will reveal statistical data that will shed light on the development in the fields mentioned. As will be noted, total R&D investment in Latin American and Caribbean countries remained constant since 1997. In spite of having reached a general increase in publications without international collaboration in LAC nations, the countries with greatest research productivity in Latin America (Argentina, Mexico, Brazil, and Chile) have strengthened their international collaboration with the United States, France, Germany, and Italy through close links associated with the formation processes of their researchers. Academic and research integration is evaluated through joint authorship of scientific articles, evidencing close collaboration in fields of research. This principle has been used in the creation of cooperation networks among participating nations. As far as networks of research on condensed matter, novel materials, and nanotechnology, the Andean nations have not consolidated a regional network allowing permanent and effective cooperation in research and technological development; as would be expected, given their idiomatic and cultural similarities, their historical background, and geographical proximity, which have been integrating factors in other research areas or socio-economic aspects. This

  17. [Decriminalizing traditional Andean medicine: an interview with Walter Álvarez Quispe]. (United States)

    Quispe, Walter Álvarez; Loza, Carmen Beatriz


    Walter Álvarez Quispe, a Kallawaya healer and biomedical practitioner specializing in general surgery and gynecology, presents the struggle of traditional and alternative healers to get their Andean medical systems depenalized between 1960 and 1990. Bolivia was the first country in Latin America and the Caribbean to decriminalize traditional medicine before the proposals of the International Conference on Primary Health Care (Alma-Ata, 1978). The data provided by the interviewee show that the successes achieved, mainly by the Kallawayas, stem from their own independent initiative. These victories are not the result of official policies of interculturality in healthcare, although the successes achieved tend to be ascribed to them.

  18. Vascular Endothelial Growth Factor-A Is Associated with Chronic Mountain Sickness in the Andean Population


    Espinoza, Jose R.; Alvarez, Giancarlo; León-Velarde, Fabiola; Ju Preciado, Hugo F.; Macarlupu, Jose-Luis; Rivera-Ch, Maria; Rodriguez, Jorge; Favier, Judith; Gimenez-Roqueplo, Anne-Paule; Richalet, Jean-Paul


    Espinoza, Jose R., Giancarlo Alvarez, Fabiola León-Velarde, Hugo F. Ju Preciado, Jose-Luis Macarlupu, Maria Rivera-Ch, Jorge Rodriguez, Judith Favier, Anne-Paule Gimenez-Roqueplo, and Jean-Paul Richalet. Vascular endothelial growth factor-A is associated with chronic mountain sickness in Andean population. High Alt Med Biol. 15:146–154, 2014.—A study of chronic mountain sickness (CMS) with a candidate gene—vascular endothelial growth factor A (VEGFA)—was carried out in a Peruvian population l...

  19. Role of carbon and climate in forming the Páramo, an Andean evolutionary hotspot (United States)

    Hill, Daniel


    According to a number of genetic diversification measures the Páramo grasslands of the high equatorial Andes show the greatest rates of speciation on the planet. This is probably driven by contrasting ranges of the ecosystem between glacial and interglacial periods of the Pleistocene. During the warm interglacial periods the treeline is high in the Andes restricting the Páramos to the highest regions of the Andean mountain chain, while in the cool glacial periods the Páramo areas expand and probably coalesce, bringing isolated populations into contact with each other. The origin of the Páramo ecosystem is placed close to the end of the Pliocene and has been related to the finale of regional Andean mountain building. However, this formation date is also coincident with the global cooling at the end of the Pliocene, as Northern Hemisphere glaciation and the bipolar Pleistocene ice ages begin. Furthermore, it is estimated that atmospheric CO2 concentrations dropped from the 400 ppmv typical of the Pliocene to values more typical of the Pleistocene at around this time. Global climate model simulations, coupled with a high resolution biome model, give us the opportunity to test these competing hypotheses for the formation of the Páramo ecosystem. A series of HadCM3 climate model simulations are presented here varying the height of the highest altitude Andes and the global climate from its pre-industrial state to the Pliocene. The climate are topographic changes are varied both independently and together. These climatologies are then used to drive a high-resolution biome model, BIOME4, and simulate the impact on Andean vegetation. These models seem to reproduce the observed changes in high altitude grassland biomes during the Pliocene. The climate and biome modelling presented here show that the climate changes associated with the Plio-Pleistocene boundary are the primary cause of the initial formation of this unique and important ecosystem. Although the reduction

  20. Kunpeng Copper:The largest Copper Smelting Company of Sichuan

    Institute of Scientific and Technical Information of China (English)


    <正>On September 9,Liangshan Mining Company’s 100,000 tons/year cathode copper project kicked off.It is another key project of the company following the successful launch of the 100,000 tons/year anode copper project.Based on ISA copper smelting technology of the largest open-cast copper mine in southwest China,

  1. Posttranslational regulation of copper transporters

    NARCIS (Netherlands)

    van den Berghe, P.V.E.


    The transition metal copper is an essential cofactor for many redox-active enzymes, but excessive copper can generate toxic reactive oxygen species. Copper homeostasis is maintained by highly conserved proteins, to balance copper uptake, distribution and export on the systemic and cellular level. Th

  2. Fabricating Copper Nanotubes by Electrodeposition (United States)

    Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel


    Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

  3. Miocene tectonism and the separation of cis- and trans-Andean river basins: Evidence from Neotropical fishes (United States)

    Albert, James S.; Lovejoy, Nathan R.; Crampton, William G. R.


    The fish fauna of trans-Andean river basins in northwestern South America is ancient and diverse, including 14% (558 of 4,085) of all Neotropical teleost species and representing 88% of the orders and 79% of the families. The evolutionary histories of these lineages provide many examples to test models of the tectonic uplift that isolated the trans-Andean basins. We report the results of two newly compiled data sets of phylogenetic and biogeographic information on the freshwater fishes of the region: (1) species-level phylogenies for 26 Neotropical freshwater teleost taxa, with a minimum of 37 cis-/trans-Andean clades and (2) species distributions for 641 genera of Neotropical freshwater teleosts, with a minimum of 140 cis-/trans-Andean clades. Although it provides only about one-quarter the total number of cis-/trans-Andean clades, species phylogeny preserves a more accurate record of the temporal sequence of basin isolation. Phylogenies using gene sequences also may provide estimates on the timing of lineage divergences. However, the great majority (70%) of available species phylogenies for Neotropical freshwater teleosts employ comparative morphology alone, partly because species-level sampling for most taxa requires collections over large spatial (10 3-10 4 km) scales, and collections of whole specimens for morphological study are readily available for many taxa from natural history museums. Fish species phylogenies are partially concordant with patterns of drainage basin isolation generated from geological data on the Miocene of northwestern South America, which associate the initial rise of the Eastern Cordillera (˜1 2 Ma) with the hydrological isolation of the Magdalena and Pacific Slope regions and the rise of the Merida Andes (˜8 Ma) with the isolation of the modern Maracaibo and Orinoco basins. Although some phylogenies unite taxa from the Maracaibo and cis-Andean Orinoco, a more common set of area relationships occurs between clades exclusive to the

  4. Age and geochemistry of host rocks of the Cobre Panama porphyry Cu-Au deposit, central Panama: Implications for the Paleogene evolution of the Panamanian magmatic arc (United States)

    Baker, Michael J.; Hollings, Peter; Thompson, Jennifer A.; Thompson, Jay M.; Burge, Colin


    The Cobre Panama porphyry Cu-Au deposit, located in the Petaquilla district of central Panama, is hosted by a sequence of medium- to high-K calc-alkaline volcanic and sub-volcanic rocks. New crystallisation ages obtained from a granodiorite Petaquilla batholith and associated mineralised diorite to granodiorite porphyry stocks and dikes at Cobre Panama indicate that the batholith was emplaced as a multi-phase intrusion, over a period of ~ 4 million years from 32.20 ± 0.76 Ma to 28.26 ± 0.61 Ma, while the porphyritic rocks were emplaced over a ~ 2 million year period from 28.96 ± 0.62 Ma to 27.48 ± 0.68 Ma. Both the volcanic to sub-volcanic host rocks and intrusive rocks of the Cobre Panama deposit evolved via fractional crystallisation processes, as demonstrated by the major elements (e.g. Al2O3, Fe2O3, TiO2 and MgO) displaying negative trends with increasing SiO2. The Petaquilla intrusive rocks, including the diorite-granodiorite porphyries and granodiorite batholith, are geochemically evolved and appear to have formed from more hydrous magmas than the preceding host volcanic rocks, as evidenced by the presence of hornblende phenocrysts, higher degrees of large-ion lithophile element (LILE) and light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion, and higher Sr/Y and La/Yb values. However, the degree of LREE enrichment, HREE depletion and La/Yb values are insufficient for the intrusive rocks to be considered as adakites. Collectively, the volcanic and intrusive rocks have LILE, REE and mobile trace element concentrations similar to enriched Miocene-age Cordilleran arc magmatism found throughout central and western Panama. Both the Petaquilla and Cordilleran arc magmatic suites are geochemically more evolved than the late Cretaceous to Eocene Chagres-Bayano arc magmas from northeastern Panama, as they display higher degrees of LILE and LREE enrichment. The geochemical similarities between the Petaquilla and Cordilleran arc

  5. Sequence of Late Jurassic-Early Cretaceous magmatic-hydrothermal events in the Xiong'ershan region, Central China: An overview with new zircon U-Pb geochronology data on quartz porphyries (United States)

    Deng, Jun; Gong, Qingjie; Wang, Changming; Carranza, Emmanuel John M.; Santosh, M.


    Recent investigations have revealed several large Au and Mo deposits in the Xiong'ershan region, Central China. Most quartz porphyries associated with the mineralization occur as dikes and apophyses, or as rubbles cemented in mineralized breccia pipes. Three types of quartz porphyries were sampled from the Leimengou Mo deposit, the Qiyugou Au deposit, and the Niutougou Au deposit. LA-ICP-MS zircon U-Pb analysis was performed in zircons from two quartz porphyries; the results yielded ages of 125.4 ± 0.77 Ma for Leimengou Mo deposit and 150.1 ± 1.1 Ma for Qiyugou Au deposit. The magma source of Leimengou quartz porphyry is similar to that of the mineralized cementing material in breccia pipes of the Qiyugou Au deposit, whereas the magma source of Qiyugou quartz porphyry is the same as that of quartz porphyries in Niutougou Au deposit. Based on the new U-Pb isotopic ages of granitic plutons reported in this study, together with the age data in the literature, we identify distinct magmatic pulses in the Xiong'ershan region at ca.160, 150, 143, 133, 125, and 115 Ma during the Late Jurassic-Early Cretaceous. The ages of Au and Mo mineralization coincide with the thermal events at about 115, 125, 133, and 143 Ma are considered to be co-eval with granitic magmatism. No mineralization ages of 150 and 160 Ma thermal events have been previously reported. Our study demonstrates Late Jurassic-Early Cretaceous multiple magmatic pulses and mineralization in the Xiong'ershan region.

  6. Two new trans-Andean species of Imparfinis Eigenmann & Norris, 1900 (Siluriformes: Heptapteridae from Colombia

    Directory of Open Access Journals (Sweden)

    Armando Ortega-Lara

    Full Text Available Two new species of Imparfinis are described from the trans-Andean region of Colombia. Imparfinis timana is diagnosed by having longer anal fin base (12.4-15.5% in SL, in combination with long adipose fin (24.6-31.3% in SL, 5-6 gill rakers on the first ceratobranchial, 42-43 vertebrae and additional measurements. Imparfinis usmai is distinguished by the combination of first ray of dorsal fin longest, but not projected as a long filament, long adipose fin (21.1-27.0% in SL, maxillary barbel exceeding pelvic-fin base, 39-40 vertebrae, upper caudal-fin lobe pointed and longer than lower lobe, lower lobe rounded, 7-8 gill rakers on the first ceratobranchial, as well as additional measurements. Imparfinis timana is only known from río Guarapas, a small tributary of the upper course of the río Magdalena. Imparfinis usmai is broadly distributed in the upper basin of ríos Cauca and Magdalena, and in the lower Patía river basin. The restricted distribution of I. nemacheir to trans-Andean drainages (Atrato, Magdalena, and Lago de Maracaibo is also discussed.

  7. An Andean radiation: polyploidy in the tree genus Polylepis (Rosaceae, Sanguisorbeae). (United States)

    Schmidt-Lebuhn, A N; Fuchs, J; Hertel, D; Hirsch, H; Toivonen, J; Kessler, M


    The Andean tree genus Polylepis (Rosaceae) is notorious for the high morphological plasticity of its species and the difficulty in their circumscription. The evolutionary mechanisms that have driven diversification of the genus are still poorly understood, with factors as diverse as ecological specialisation, reticulate evolution, polyploidisation and apomixis being proposed to contribute. In the present study, chromosome counts, flow cytometry and stomata guard cell size measurements were employed to document for the first time the presence of polyploidy in the genus and to infer ploidy levels for most species. Inferred ploidy levels show a clear progression from diploidy in cloud forest species to polyploidy (tetra- to octoploidy) in the morphologically and ecologically specialised incana group, indicating that polyploidisation may have played a major role in speciation processes and the colonisation of novel habitats during the Andean uplift. At least two species of Polylepis comprise populations with varying degrees of ploidy. More extensive studies are needed to obtain a better understanding of the prevalence and effects of intraspecific polyploidy in the genus.

  8. Composition and diversity of High Andean in the Fauna Production Reserve Chimborazo, Ecuador

    Directory of Open Access Journals (Sweden)

    Jorge Caranqui


    Full Text Available The present study inquire the floristic diversity of 9 sampling in four plots of 1 m² of high andean in several locations in the “Reserva de Producción de Fauna Chimborazo”. For the development of this study, we used an adaptation of the method of plots “Gloria”. With coverage (% in each of the plots, Further the diversity indices and similarity with respective analysis were obtained. The data obtained reflect a diversity that can range from medium to low, believe that this is due to anthropogenic activities that have taken place in these ecosistems. With the presence mostly Calamagrostis intermedia, it could establish that the type of vegetation is herbaceous in high andean is higher percentage; is the species that is almost always present in most types of vegetation of the RPF Chimborazo and high dominance that influences the results of low floristic diversity indices was found in the analysis. As a result the most abundant family Asteraceae is well Poaceae.

  9. Geochemical Characteristics and Significance of Major Elements, Trace Elements and REE in Mineralized Altered Rocks of Large-Scale Tsagaan Suvarga Cu-Mo Porphyry Deposit in Mongolia

    Institute of Scientific and Technical Information of China (English)


    The alteration types of the large-scale Tsagaan Suvarga Cu-Mo porphyry deposit mostly comprise stockwork silicification, argillization, quartz-sericite alteration, K-silicate alteration, and propylitization.The mineralized and altered zones from hydrothermal metallogenic center to the outside successively are Cu-bearing stockwork silicification zone, Cu-bearing argillized zone, Cu-Mo-bearing quartz-sericite alteration zone, Cu-Mo-bearing K-silicate alteration zone, and propylitization zone.The K-silicate alteration occurred in the early phase, quartz-sericite alteration in the medium phase, and argillization and carbonatization (calcite) in the later phase.Ore-bearing-altered rocks are significantly controlled by the structure and fissure zones of different scales, and NE- and NW-trending fissure zones could probably be the migration pathways of the porphyry hydrothermal system.Results in this study indicated that the less the concentrations of REE, LREE, and HREE and the more the extensive fractionation between LREE and HREE, the closer it is to the center circulatory hydrothermal ore-forming and the more extensive silicification.The exponential relationship between the fractionation of LREE and HREE and the intensity of silicification and K-silicate alteration was found in the Cu-Mo deposit studied.The negative Eu anomaly, normal Eu, positive Eu anomaly and obviously positive Eu anomaly are coincident with the enhancement of Na2O and K2O concentrations gradually, which indicated that Eu anomaly would be significantly controlled by the alkaline metasomatism of the circulatory hydrothermal ore-forming system.Therefore, such characteristics as the positive Eu anomaly, the obvious fractionation between LREE and HREE and their related special alteration lithofacies are suggested to be metallogenic prognostic and exploration indications for Tsagaan Suvarga-style porphyry Cu-Mo deposits in Mongolia and China.

  10. Targeting copper in cancer therapy: 'Copper That Cancer'. (United States)

    Denoyer, Delphine; Masaldan, Shashank; La Fontaine, Sharon; Cater, Michael A


    Copper is an essential micronutrient involved in fundamental life processes that are conserved throughout all forms of life. The ability of copper to catalyze oxidation-reduction (redox) reactions, which can inadvertently lead to the production of reactive oxygen species (ROS), necessitates the tight homeostatic regulation of copper within the body. Many cancer types exhibit increased intratumoral copper and/or altered systemic copper distribution. The realization that copper serves as a limiting factor for multiple aspects of tumor progression, including growth, angiogenesis and metastasis, has prompted the development of copper-specific chelators as therapies to inhibit these processes. Another therapeutic approach utilizes specific ionophores that deliver copper to cells to increase intracellular copper levels. The therapeutic window between normal and cancerous cells when intracellular copper is forcibly increased, is the premise for the development of copper-ionophores endowed with anticancer properties. Also under investigation is the use of copper to replace platinum in coordination complexes currently used as mainstream chemotherapies. In comparison to platinum-based drugs, these promising copper coordination complexes may be more potent anticancer agents, with reduced toxicity toward normal cells and they may potentially circumvent the chemoresistance associated with recurrent platinum treatment. In addition, cancerous cells can adapt their copper homeostatic mechanisms to acquire resistance to conventional platinum-based drugs and certain copper coordination complexes can re-sensitize cancer cells to these drugs. This review will outline the biological importance of copper and copper homeostasis in mammalian cells, followed by a discussion of our current understanding of copper dysregulation in cancer, and the recent therapeutic advances using copper coordination complexes as anticancer agents.

  11. Ore grade decrease as life cycle impact indicator for metal scarcity: the case of copper. (United States)

    Vieira, Marisa D M; Goedkoop, Mark J; Storm, Per; Huijbregts, Mark A J


    In the life cycle assessment (LCA) of products, the increasing scarcity of metal resources is currently addressed in a preliminary way. Here, we propose a new method on the basis of global ore grade information to assess the importance of the extraction of metal resources in the life cycle of products. It is shown how characterization factors, reflecting the decrease in ore grade due to an increase in metal extraction, can be derived from cumulative ore grade-tonnage relationships. CFs were derived for three different types of copper deposits (porphyry, sediment-hosted, and volcanogenic massive sulfide). We tested the influence of the CF model (marginal vs average), mathematical distribution (loglogistic vs loglinear), and reserve estimate (ultimate reserve vs reserve base). For the marginal CFs, the statistical distribution choice and the estimate of the copper reserves introduce a difference of a factor of 1.0-5.0 and a factor of 1.2-1.7, respectively. For the average CFs, the differences are larger for these two choices, i.e. respectively a factor of 5.7-43 and a factor of 2.1-3.8. Comparing the marginal CFs with the average CFs, the differences are higher (a factor 1.7-94). This paper demonstrates that cumulative grade-tonnage relationships for metal extraction can be used in LCA to assess the relative importance of metal extractions.

  12. Foreland sedimentary record of Andean mountain building during advancing and retreating subduction (United States)

    Horton, Brian K.


    As in many ocean-continent (Andean-type) convergent margins, the South American foreland has long-lived (>50-100 Myr) sedimentary records spanning not only protracted crustal shortening, but also periods of neutral to extensional stress conditions. A regional synthesis of Andean basin histories is complemented by new results from the Mesozoic Neuquén basin system and succeeding Cenozoic foreland system of west-central Argentina (34-36°S) showing (1) a Late Cretaceous shift from backarc extension to retroarc contraction and (2) an anomalous mid-Cenozoic (~40-20 Ma) phase of sustained nondeposition. New detrital zircon U-Pb geochronological results from Jurassic through Neogene clastic deposits constrain exhumation of the evolving Andean magmatic arc, retroarc thrust belt, foreland basement uplifts, and distal eastern craton. Abrupt changes in sediment provenance and distal-to-proximal depositional conditions can be reconciled with a complex Mesozoic-Cenozoic history of extension, post-extensional thermal subsidence, punctuated tectonic inversion involving thick- and thin-skinned shortening, alternating phases of erosion and rapid accumulation, and overlapping igneous activity. U-Pb age distributions define the depositional ages of several Cenozoic stratigraphic units and reveal a major late middle Eocene-earliest Miocene (~40-20 Ma) hiatus in the Malargüe foreland basin. This boundary marks an abrupt shift in depositional conditions and sediment sources, from Paleocene-middle Eocene distal fluviolacustrine deposition of sediments from far western volcanic sources (Andean magmatic arc) and subordinate eastern cratonic basement (Permian-Triassic Choiyoi igneous complex) to Miocene-Quaternary proximal fluvial and alluvial-fan deposition of sediments recycled from emerging western sources (Malargüe fold-thrust belt) of Mesozoic basin fill originally derived from basement and magmatic arc sources. Neogene eastward advance of the fold-thrust belt involved thick

  13. Phenolic compound contents and antioxidant activity in plants with nutritional and/or medicinal properties form the Peruvian Andean region

    NARCIS (Netherlands)

    Chirinos, R.; Pedreschi Plasencia, R.P.; Rogez, H.


    Total phenolic compounds (TPC) and antioxidant activities using different assays (DPPH, ABTS and ORAC) in fruits, grains, leaves, seeds, roots and tubers from 27 different Peruvian Andean plants used in folk medicine or/and as food by the native population were evaluated in order to use these as nat

  14. Landscape genetics, historical isolation and cross-Andean gene flow in the wax palm, Ceroxylon echinulatum (Arecaceae)

    DEFF Research Database (Denmark)

    Trénel, P.; Hansen, Michael Møller; Nordmand, S.


    and landscape genetics of the Andean wax palm Ceroxylon echinulatum (Arecaceae) that occurs in two narrow bands of montane forests on each side of the Andes in Ecuador and northeastern Peru. First, we tested the hypothesis of C. echinulatum being a geographic cline species crossing the Andes in the Amotape...

  15. Contextual Analysis of the Decision To Adopt a Regional Satellite System: The Case of the Andean CONDOR. (United States)

    Ferreira, Leonardo; Mody, Bella

    Acknowledging the importance of communications in economic development, this paper discusses the rationale behind the decision of the Andean Pact nations of Bolivia, Colombia, Ecuador, Peru, and Venezuela to develop a regional satellite communication system to be known as CONDOR. The application of contextual theorizing to the decision-making…

  16. Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.


    Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 in were examined along two altitudinal transects crossing the U

  17. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud


    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  18. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G


    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

  19. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago (United States)

    Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.


    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200–800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700–50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures. PMID:28139760

  20. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago (United States)

    Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.


    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200–800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700–50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

  1. Landscape genetics, historical isolation and cross-Andean gene flow in the wax palm, Ceroxylon echinulatum (Arecaceae). (United States)

    Trénel, Philipp; Hansen, Michael M; Normand, Signe; Borchsenius, Finn


    Knowledge of the role of landscapes in shaping genetic connectivity and divergence is essential for understanding patterns of biogeography and diversity. This is particularly relevant for the Andes region, a major biodiversity hotspot of relatively recent origin. We examined the phylogeography and landscape genetics of the Andean wax palm Ceroxylon echinulatum (Arecaceae) that occurs in two narrow bands of montane forests on each side of the Andes in Ecuador and northeastern Peru. First, we tested the hypothesis of C. echinulatum being a geographic cline species crossing the Andes in the Amotape-Huancabamba zone (AHZ) of southern Ecuador/northern Peru, as indicated by observations on fruit morphology. Second, we assessed the timeframe of cross-Andean divergence, and third, we investigated the impact of contemporary and historical landscape features on observed spatio-genetic patterns. Individual-based Bayesian clustering (BC) identified a northeastern, southeastern, southwestern, and northwestern cluster, with areas of genetic discontinuity coinciding with the Andes and the Giron-Paute deflection. F-statistics derived from BC suggested an east-to-west dispersal history. Population-based analyses revealed strong genetic structuring at both small and large geographic scales. Interpopulation relationships and Mantel tests strongly supported the cline model with cross-Andean dispersal in the AHZ. Along the cline, gene flow measured as F(ST) was mainly limited by distance, with less but significant impact of climatic friction. Coalescent analysis revealed that cross-Andean divergence took place during the Quaternary. Significant historical isolation (R(ST) > F(ST)) was found in the southwestern population. The current study illustrates a joint effect of founder dynamics, divergence by distance and historical isolation on patterns of Andean diversity and distribution.

  2. Two new cis-Andean species of the South American catfish genus Megalonema allied to trans-Andean Megalonema xanthum, with description of a new subgenus (Siluriformes: Pimelodidae

    Directory of Open Access Journals (Sweden)

    John G. Lundberg

    Full Text Available A revised diagnosis of the pimelodid catfish genus Megalonema is given based on synapomorphic features of the Weberian complex and gas bladder. Megalonema xanthum from the Magdalena River is redescribed. Two new cis-Andean species of Megalonema are described, M. amaxanthum n. sp. from the Amazon River basin, and M. orixanthum n. sp. from the Orinoco River basin. These three species are differentially diagnosed by shape and size of the supraoccipital posterior process, adipose-fin shape, vertebral counts, eye size, premaxillary bone shape and dentition, length of the anal-fin base, width between the posterior nostrils and presence/absence of dentations on the pectoral spine. Eretmomegalonema new subgenus is established for M. xanthum, M. amaxanthum and M. orixanthum and supported by the uniquely synapomorphic paddle-like structure of its pelvic fin and hypertrophied basipterygium. Unambiguous synapomorphies indicate a sister-group relationship between M. amaxanthum and M. orixanthum, with M. xanthum basal to this pair. This topology is congruent with the Neogene origins of separate Magdalena, Amazon and Orinoco basins suggesting vicariant control of diversification of Eretmomegalonema.

  3. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  4. Erosion of particulate organic material from an Andean river and its delivery to the Amazon Basin (United States)

    Clark, Kathryn; Hilton, Robert; West, A. Joshua; Robles Caceres, Arturo; Grocke, Darren; Marthews, Toby; Asner, Greg; New, Mark; Mahli, Yadvinder


    Organic carbon and nutrients discharged by mountainous rivers can play an important role in biogeochemical cycles from regional to global scales. The eastern Andes host productive forests on steep, rapidly eroding slopes, a combination that is primed to deliver sediment, carbon and nutrients to the lowland Amazon River. We quantify clastic sediment and particulate organic carbon (POC) discharge for the Kosñipata River, Peru, an Andean tributary of the Madre de Dios River, using suspended sediment samples and discharge measurements over one year at two gauging stations. Calculations of sediment yield on the basis of this data suggest that the Madre de Dios basin may have erosion rates ˜10 times greater than the Amazon Basin average. The total POC yield over the sampling period was up to five times higher than the yield in the lowland Amazon Basin, with most POC (70-80%) exported between December and March in the wet season. We use radiocarbon, stable C isotopes and C/N ratios to distinguish between the erosion and discharge of POC from sedimentary rocks (petrogenic POC) and POC eroded from the modern terrestrial biosphere, from vegetation and soil (biospheric POC). We find that biospheric POC discharge was significantly enhanced during flood events, over that of clastic sediment and petrogenic POC. The ultimate fate of the eroded POC may play a central role in the net carbon budget of Andean forest. In these forests, net productivity minus heterotrophic respiration is close to zero at the scale of forest plots, and the erosion of biospheric POC by this Andean river is sufficiently rapid that its fate downstream (sedimentary burial/preservation versus oxidation/degradation) may determine whether the mountain forest is a carbon sink or source to the atmosphere. In addition, the measured discharge of petrogenic POC suggests that fluxes from the Andes may be considerably higher than measured downstream in the Madeira River. If this petrogenic POC is oxidised rather

  5. Imaging variations in the central Andean mantle and the subducting Nazca slab with teleseismic tomography (United States)

    Scire, Alissa

    The Nazca-South America convergent margin is marked by the presence of the Andean mountain belt, which stretches along the 8000-km long western margin of the South American plate. The subduction zone is characterized by significant along-strike changes in both upper plate structure and slab geometry that make it an ideal region to study the relationship between the subducting slab, the surrounding mantle, and the overriding plate. This dissertation summarizes the results of three finite frequency teleseismic tomography studies of the central Nazca-South America subduction zone which improve our understanding of how along-strike variations in the Andean mountain belt and the subducting Nazca plate interact with each other and with the surrounding mantle. This is accomplished by first focusing on two smaller adjacent regions of the central Andes to explore upper mantle variations and then by using a combined dataset, which covers a larger region, to image the deeply subducted Nazca slab to investigate the fate of the slab. The first study focuses on the central Andean upper mantle under the Altiplano-Puna Plateau where normally dipping subduction of the Nazca plate is occurring (18° to 28°S). The shallow mantle under the Eastern Cordillera is generally fast, consistent with either underthrusting of the Brazilian cratonic lithosphere from the east or a localized "curtain" of delaminating material. Additional evidence for delamination is seen in the form of high amplitude low velocities under the Puna Plateau, consistent with proposed asthenospheric influx following lithospheric removal. In the second study, we explore the transition between normal and flat subduction along the north edge of the Altiplano Plateau (8° to 21°S). We find that the Peruvian flat slab extends further inland along the projection of the Nazca Ridge than was previously proposed and that when re-steepening of the slab occurs, the slab dips very steeply (˜70°) down through the mantle

  6. Peculiar seismotectonic characteristics of Nazca's subducted slab, in the Andean region: Why do they exist? (United States)

    Berrocal, J.; Fernandes, C.


    The peculiar morphology of Wadati-Benioff Zone (WBZ) beneath Andean region presents controversial seismotectonic characteristics of the subducting Nazca plate beneath South American plate: WBZ with an almost flat behaviour under Central-Northern Peru region, and beneath Central Chile region, intercalated with steeply portion of the slab; the almost completely aseismic portion between 300 and 500 km of depth; the existence of deep earthquakes in South American and their controversial focal mechanism. There are several hypotheses trying to explain a suitable origin for those deep earthquakes that occur in depths between 500 and almost 700 km, where the occurrence of brittle failure is improbable to exist due to the presence of high temperature and pressure conditions at those depths. We propose in this work - based mainly in the spatial distribution of relocated hypocentres, and in the joint interpretation with recent published results related to seismotectonic aspects of Andean region - a top-to- northwest shear of the portion of Nazca subducting plate between 24°S and 01°S, in such an amount that its deepest corresponding extremes, at around 600 km of depth, seem to be presently, under latitudes between 29°S and 06°S, respectively. The proposed northwestern displacement of South American plate may be provoking that shear process of Nazca slab, which should be larger at shallower depths of the slab, and limited to those latitudes below the Andean region. The NW displacement of Nazca slab could explain the existence of flat subduction beneath Central-Northern Peru region as a consequence of a probable northwards migration of the buoyant Nazca ridge after subduction under South American plate in around 15°S. Similar explanation could be used for the flat WBZ beneath Central Chile and the Juan Fernandez ridge. This hypothesis permits to infer for some very deep South American earthquakes shear, planar mechanisms at high pressure, some times as almost horizontal

  7. Ecological Resilience and Resistance in the Hyper Diverse Forests on the Eastern Andean Flank (Mera, Ecuador) (United States)

    Keen, H. F.; Gosling, W. D.; Montoya, E.; Sherlock, S.; Mothes, P. A.


    Today the Neotropics contain some of the world's most biodiverse and threatened ecosystems. Sediments obtained from two radiocarbon infinite (>48,000 years) stratigraphic sections on the eastern Andean flank, provide new insight into the relationship between biodiversity and disturbance during the Pleistocene (~200,000 years). Pollen analysis of modern and fossil material indicates that hyper diverse forest vegetation has been a feature of the Andean flank landscape for 100,000 years (pollen richness: modern = 44, fossil = 48). Correlation of past vegetation with disturbance events (volcanic and fluvial) indicates the response of hyper-diverse forest to past landscape scale change. Pollen records from near Mera (01°27 S, 78°06 W; 1117 m asl) indicate two major changes in the pollen assemblage, with forest communities dominated by: i) Hedyosmum-Alnus-Ilex, and ii) Combretaceae-Melastomataceae-Myrtaceae. These two pollen assemblages most closely resemble modern vegetation cloud forest (2500-3400m asl) and lower montane rain forest (700-2499 m asl) respectively. Sedimentary evidence suggests that at least 21 volcanic events and three changes in the local fluvial regime perturbed the regional landscape during the period of deposition. However, there is no evidence for volcanic or fluvial disturbance events causing a persistent change in vegetation community. Volcanic events (tephra deposits) are associated with increased fire (charcoal particles), and changes in vegetation (pollen grains); however, within ~50cm of sediment accumulation above each tephra, pollen assemblages revert to pre-deposition compositions. Increased fluvial influence (gravel deposits) is associated with elevated input of pollen from taxa today found at higher elevations (Podocarpus-Celtis). The input of high elevation taxa concomitant with fluvial deposits is most likely indicative of an increase in long-distance transport of pollen along water courses originating in the Andes. Our data indicate

  8. Integración regional andina en salud Health in Andean regional integration

    Directory of Open Access Journals (Sweden)

    Carlos A. Agudelo


    Full Text Available A pesar su historia compartida, los países de la Región Andina presentan una diversidad social y política que genera realidades sanitarias heterogéneas y procesos de integración complejos. Se han dado por décadas procesos generales, como la Asociación Latinoamericana de Libre Comercio y la Asociación Latinoamericana de Integración, o de alcance regional como la Comunidad Andina de Naciones, la Comunidad del Caribe y el Mercado Común Centroamericano. En el campo específico de la salud se cuenta con un instrumento en la Región Andina, el Convenio Hipólito Unánue, creado en 1971. Estos procesos de integración se han concentrado en los aspectos económicos, con base en acuerdos de preferencias arancelarias, los cuales han generado, en el largo plazo, un intercambio comercial apreciable. En el campo de la salud se ha avanzado menos, en términos de procesos que ponen en común experiencias nacionales, conocimientos y capacidades. El análisis de las experiencias de integración en salud muestra que esta depende de las fortalezas de cada país y, en gran parte, de los procesos políticos nacionales.Despite their shared history, the Andean countries are socially and politically diverse, with heterogeneous health realities and complex integration processes. General developments such as the Latin American Free Trade Association and Latin American Integration Association have existed for decades, along with others of a regional scope, like the Andean Community of Nations, Caribbean Community, and Central American Common Market. The health field has a specific instrument in the Andean Region called the Hipólito Unánue Agreement, created in 1971. Integration processes have concentrated on economic aspects, based on preferential customs agreements that have led to an important long-term increase in trade. Less progress has been made in the field of health in terms of sharing national experiences, knowledge, and capabilities. Analysis of

  9. Extremely Re-Rich Molybdenite from Porphyry Cu-Mo-Au Prospects in Northeastern Greece: Mode of Occurrence, Causes of Enrichment, and Implications for Gold Exploration

    Directory of Open Access Journals (Sweden)

    Tamara Kartal


    Full Text Available Extremely Re-rich molybdenite occurs with pyrite in sodic–calcic, sodic–sericitic and sericitic-altered porphyritic stocks of granodioritic–tonalitic and granitic composition in the Sapes–Kirki–Esymi, Melitena and Maronia areas, northeastern Greece. Molybdenite in the Pagoni Rachi and Sapes deposits is spatially associated with rheniite, as well as with intermediate (Mo,ReS2 and (Re,MoS2 phases, with up to 46 wt % Re. Nanodomains and/or microinclusions of rheniite may produce the observed Re enrichment in the intermediate molybdenite–rheniite phases. The extreme Re content in molybdenite and the unique presence of rheniite in porphyry-type mineralization, combined with preliminary geochemical data (Cu/Mo ratio, Au grades may indicate that these deposits have affinities with Cu–Au deposits, and should be considered potential targets for gold mineralization in the porphyry environment. In the post-subduction tectonic regime of northern Greece, the extreme Re and Te enrichments in the magmatic-hydrothermal systems over a large areal extent are attributed to an anomalous source (e.g., chemical inhomogenities in the mantle-wedge triggered magmatism, although local scale processes cannot be underestimated.

  10. The possible contribution of a mantle-derived fluid to the Ningwu porphyry iron deposits- Evidence from carbon and strontium isotopes of apatites

    Institute of Scientific and Technical Information of China (English)

    Jinjie Yu; Jingwen Mao; Changqing Zhang


    Apatite is a characteristic mineral for the iron deposits in the Ningwu region. Apatite shows a range of δ13CPDB values from -9.6‰ to-0.6‰, and most of them with the δ13CPDB values distributed in a range of mantle carbon (I.e., -2%0 to -9%0), except for samples T-06-1and J-06-3. Apatites in the Ningwu porphyry iron deposits yield a narrow variation range of 87Sr/86Sr values from 0.706326 to 0.707577,similar to those of the volcanic and subvolcanic rocks and higher than that of a typical mantle-derived magmatic apatite (I.e., about0.7040), indicating that formation of the apatites was involved with crust material contamination. δ13CPDB and 87Sr/86Sr values of the apatite indicate a possible contribution of mantle-derived fluid and material to formation of the Ningwu porphyry iron deposits,supported by regional geology, regional gravities and geochemistry of the volcanic and subvolcanic rocks in the Ningwu region.

  11. Geological and geochemical characteristics of the Aksug porphyry Cu-Mo system, Altay-Sayan region, Russia%俄罗斯阿尔泰-Sayan地区Aksug斑岩Cu-Mo体系的地质与地球化学特征

    Institute of Scientific and Technical Information of China (English)

    Berzina AN; Berzina AP


    The Aksug deposit, located in Ahay-Sayan region of Russia, is one of the largest porphyry Cu-Mo deposits in Southern Siberia. The ore-bearing porphyries of the Aksug porphyry Cu-Mo system were formed in post-collisional environment. Geochemically they belong to calk-alkaline and high K-calk-alkaline series. Rocks are characterized by enrichment of LILE and depletion of HSFE and HREE, showing the importance of subduction-related components in magma generation. Large plutonic intrusions that host porphyry systems have been formed during collision. The origin of porphyritic rocks is dominantly the mantle with lower crustal contribution. The mainly economically important Cu-Mo mineralization is closely related to a porphyry series in time and space, being emplaced towards the end of magmatic activity. Though the emplacement of plutonic and ore-bearing porphyry complexes took place in different geodynamic environments, both complexes are characterized by certain similarity in geochemical composition, alkalinity, trace element content, Sr isotopic composition. This fact evidently indicates a common deep-seated magmatic source (at the lower crust-upper mantle level), Low initial 87Sr/86Sr, sulfur isotopic characteristics and presence of PGE-Co-Ni mineralization in associated pyrite-chalcopyrite ores suggest that mantle source of chalcophile elements was of high importance in porphyry Cu-Mo mineralization of the Aksug deposit.

  12. Copper and Copper Proteins in Parkinson’s Disease


    Sergio Montes; Susana Rivera-Mancia; Araceli Diaz-Ruiz; Luis Tristan-Lopez; Camilo Rios


    Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased pr...

  13. Size class structure, growth rates, and orientation of the central Andean cushion Azorella compacta

    Directory of Open Access Journals (Sweden)

    Catherine Kleier


    Full Text Available Azorella compacta (llareta; Apiaceae forms dense, woody, cushions and characterizes the high elevation rocky slopes of the central Andean Altiplano. Field studies of an elevational gradient of A. compacta within Lauca National Park in northern Chile found a reverse J-shape distribution of size classes of individuals with abundant small plants at all elevations. A new elevational limit for A. compacta was established at 5,250 m. A series of cushions marked 14 years earlier showed either slight shrinkage or small degrees of growth up to 2.2 cm yr−1. Despite their irregularity in growth, cushions of A. compacta show a strong orientation, centered on a north-facing aspect and angle of about 20° from horizontal. This exposure to maximize solar irradiance closely matches previous observations of a population favoring north-facing slopes at a similar angle. Populations of A. compacta appear to be stable, or even expanding, with young plants abundant.

  14. Spatial modeling of cutaneous leishmaniasis in the Andean region of Colombia (United States)

    Pérez-Flórez, Mauricio; Ocampo, Clara Beatriz; Valderrama-Ardila, Carlos; Alexander, Neal


    The objective of this research was to identify environmental risk factors for cutaneous leishmaniasis (CL) in Colombia and map high-risk municipalities. The study area was the Colombian Andean region, comprising 715 rural and urban municipalities. We used 10 years of CL surveillance: 2000-2009. We used spatial-temporal analysis - conditional autoregressive Poisson random effects modelling - in a Bayesian framework to model the dependence of municipality-level incidence on land use, climate, elevation and population density. Bivariable spatial analysis identified rainforests, forests and secondary vegetation, temperature, and annual precipitation as positively associated with CL incidence. By contrast, livestock agroecosystems and temperature seasonality were negatively associated. Multivariable analysis identified land use - rainforests and agro-livestock - and climate - temperature, rainfall and temperature seasonality - as best predictors of CL. We conclude that climate and land use can be used to identify areas at high risk of CL and that this approach is potentially applicable elsewhere in Latin America. PMID:27355214

  15. [Possibilities of Lupinus mutabolis and Lupinus albus in the Andean countries]. (United States)

    Gross, R; von Baer, E


    Lupinus albus and Lupinus mutabilis may achieve importance among the andean countries in which soy bean can not grow due to ecological reasons. Both lupin varieties are outstanding because of their high protein and oil content. Its alkaloid content limits the lupins usage; however the bitter substances can be eliminated by means of genetic selection or technological processing. Beside the intoxication caused by alkaloids exists the lupinosis, which is caused by a micotoxin. This disease can be observed when animals pasture forages which suffered under a secundary attack of fungus. According to the results obtained up to date other antimetabolic substances present in the legums have no significant importance. The lupin seed flour is adequate for animal consumption, being used for this effect in different countries. Starting next year there exist the prospects of employing Lupinus mutabilis as an oil source in Peru and Lupinus albus as proteic flour in Chile.

  16. Temporal patterns of diversification in Andean Eois, a species-rich clade of moths (Lepidoptera, Geometridae). (United States)

    Strutzenberger, P; Fiedler, K


    The timing of the origin of present day Neotropical animal diversity is still a matter of debate. For a long time, a preponderance of glacial (i.e. Pleistocene) radiations has been proposed. However, recent data from molecular clock studies indicate a preglacial origin for most of the examined taxa. We performed a fossil-calibrated molecular dating analysis of the genus Eois, which is a major component of one of the world's most diverse assemblages of herbivorous insects. We found that diversification of Eois took place in the Miocene following a pattern best explained by density-dependent diversification. A strong slowdown of diversification towards the present was detected. Diversification of Eois does overlap with increased Andean uplift and diversification of the most commonly used host plant genus Piper. These findings match the patterns found for the majority of Neotropical tetrapods and for three other unrelated, ecologically different lepidopteran genera.

  17. Invertebrate metacommunity structure and dynamics in an andean glacial stream network facing climate change

    DEFF Research Database (Denmark)

    Cauvy-Fraunié, Sophie; Espinosa, Rodrigo; Andino, Patricio;


    theory as a conceptual framework to better understand how river network structure influences the spatial organization of aquatic communities in glacierized catchments. At 51 stream sites in an Andean glacierized catchment (Ecuador), we sampled benthic macroinvertebrates, measured physico......-chemical and food resource conditions, and calculated geographical, altitudinal and glaciality distances among all sites. Using partial redundancy analysis, we partitioned community variation to evaluate the relative strength of environmental conditions (e.g., glaciality, food resource) vs. spatial processes (e.......g., overland, watercourse, and downstream directional dispersal) in organizing the aquatic metacommunity. Results revealed that both environmental and spatial variables significantly explained community variation among sites. Among all environmental variables, the glacial influence component best explained...

  18. Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction. (United States)

    Webb, Jena; Coomes, Oliver T; Mainville, Nicolas; Mergler, Donna


    Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish.


    Directory of Open Access Journals (Sweden)

    Avelar Araujo Santos Junior


    Full Text Available Religiosity of contemporary Andean indigenous peoples is constituted by a complex interaction between theology and the original items from the Christianized and ideologies historically produced phenomena such as taxation, interpenetration, removal, syncretism, resistance and reinvention. Embedded in this context was developed as a way of enhancing identity particular worldview is quite representative of their feelings and attitudes about the world, mainly in what it says respect to their territory and their community experiences and patterns of reciprocity in the socialization of traditions. Thus, our proposal in this article is to analyze some of the different elements of the symbolic representation, mythological and ritualistic of these communities, characterized by persistent conflict between a hegemonic dominance of the creative and creative autonomy.

  20. How do subduction processes contribute to forearc Andean uplift? Insights from numerical models (United States)

    Martinod, J.; Regard, V.; Letourmy, Y.; Henry, H.; Hassani, R.; Baratchart, S.; Carretier, S.


    We present numerical models to study how changes in the process of subduction may explain the observed Quaternary uplift of the Andean forearc region. Indeed, most segments of the South American Pacific coasts between 16 and 32° S have been uplifting since the Lower Pleistocene, following a period of stability of the forearc region. Models confirm that local uplift is expected to occur above ridges, this phenomenon being predominant in central Peru where the Nazca Ridge is subducting. We investigate the effects of slab pull, interplate friction and convergence velocity on the vertical displacements of the overriding plate. We propose that the global tendency to coastal uplift is accompanying the deceleration of the Nazca-South America convergence that occurred in the Pleistocene. In contrast, forearc subsidence may accompany increasing convergence velocities, as suggested by the subsidence history of the South America active margin.

  1. Size class structure, growth rates, and orientation of the central Andean cushion Azorella compacta (United States)

    Trenary, Tim; Graham, Eric A.; Stenzel, William; Rundel, Philip W.


    Azorella compacta (llareta; Apiaceae) forms dense, woody, cushions and characterizes the high elevation rocky slopes of the central Andean Altiplano. Field studies of an elevational gradient of A. compacta within Lauca National Park in northern Chile found a reverse J-shape distribution of size classes of individuals with abundant small plants at all elevations. A new elevational limit for A. compacta was established at 5,250 m. A series of cushions marked 14 years earlier showed either slight shrinkage or small degrees of growth up to 2.2 cm yr−1. Despite their irregularity in growth, cushions of A. compacta show a strong orientation, centered on a north-facing aspect and angle of about 20° from horizontal. This exposure to maximize solar irradiance closely matches previous observations of a population favoring north-facing slopes at a similar angle. Populations of A. compacta appear to be stable, or even expanding, with young plants abundant. PMID:25802811

  2. The Sabethines of Northern Andean Coffee-Growing Regions of Colombia. (United States)

    Suaza-Vasco, Juan; López-Rubio, Andrés; Galeano, Juan; Uribe, Sandra; Vélez, Iván; Porter, Charles


    Sampling for sabethine mosquitoes occurred intermittently from September 2007 to April 2013 in 17 municipalities, located in 5 departments (divisions) in the northern Andean coffee-growing regions of Colombia. Of the 9 genera within the Sabethini tribe known to occur in the Neotropical region, 6 were encountered including 15 species: Jonhbelkinia ulopus, Limatus durhamii, Sabethes ignotus, Sa. luxodens, Sa. undosus, Shannoniana fluviatilis, Trichoprosopon compressum, Tr. digitatum, Tr. evansae, Tr. pallidiventer s.l., Tr. pallidiventer s.s., Wyeomyia arthrostigma, Wy. oblita, Wy. ulocoma, and Wy. undulata. The species Sa. luxodens and Wy. undulata constitute new records for Colombia. These records broaden the knowledge of this important group that includes some important species related to the arbovirus transmission. Records are from the northern Colombian Andes, a region noted for coffee cultivation and ecotourism.

  3. An Environmental Watch System for the Andean countries: El Observatorio Andino

    CERN Document Server

    Muñoz, Ángel G; Velasquez, Ramon; Monterrey, Luis; Leon, Gloria; Ruiz, Franklyn; Recalde, Cristina; Cadena, Jaime; Mejia, Raul; Paredes, Marcos; Bazo, Juan; Reyes, Carmen; Carrasco, Gualberto; Castellon, Yaruska; Villarroel, Claudia; Quintana, Juan; Urdaneta, Avel


    An experimental Environmental Watch System, the so-called Observatorio Andino-OA (Observatorio Andino), has been implemented in Venezuela, Colombia, Ecuador, Peru, Bolivia, and Chile over the past two years. The OA is a collaborative and regional network that aims to monitor several environmental variables and develop accurate forecasts based on different scientific tools. Its overall goal is to improve risk assessments, set up Early Warning Systems, support decision-making processes, and provide easily- and intuitively-understandable spatial maps to end-users. The initiative works under the scientific and logistic coordination of the Centro de Modelado Cient\\'ifico (CMC) at Zulia University, Venezuela, and the Centro Internacional para la Investigaci\\'on del Fen\\'omeno 'El Ni\\~no' (CIIFEN), and is operated at a local level by the National Weather Services (NWSs) of the aforementioned six Andean nations. The OA provides several freely-available model outputs including meteorological and hydrological forecasts...

  4. Zircon U–Pb geochronology and geochemistry of rhyolitic tuff, granite porphyry and syenogranite in the Lengshuikeng ore district, SE China: Implications for a continental arc to intra-arc rift setting

    NARCIS (Netherlands)

    Wang, Changming; Zhang, Da; Wu, Gangguo; Xu, Yigan; Carranza, Emmanuel John M.; Zhang, Yaoyao; Li, Haikun; Geng, Jianzhen


    SE China is well known for its Mesozoic large-scale granitoid plutons and associated ore deposits. Here, zircon U–Pb geochronological and geochemical data have been used to better constrain the petrogenesis of the igneous rocks associated with porphyry Ag–Pb–Zn deposits in the Lengshuikeng ore distr

  5. Dynamic Paleogeography of the Jurassic Andean Basin: pattern of regression and general considerations on main features

    Directory of Open Access Journals (Sweden)

    J-C. Vicente


    Full Text Available Following examination of the evolution of the Jurassic Andean retroarc basin at a global scale for the Central Andes, this paper analyses the pattern of the regressive process, and discusses some general features concerning Andean Jurassic Paleogeography. The early Upper Jurassic regression obeys to an exactly reverse pattern as the one evidenced for the Lower Jurassic transgressive process. Sectors with late transgressions become those with early regressions while those with early transgressions show later regressions. This fact may indicate that the Norte Chico Isthmus (29°S to 30°30'S was a precociously emerged zone from the Bajocian. This carries again a split up between the Tarapacá and Aconcagua-Neuquén basins until their complete drying up in the Late Oxfordian following their restricted circulation. This evaporitic late stage presents great analogy with the Mediterranean «Messinian crisis» and gives evidence of a general tectonic and magmatic control on the straits. The local transgressions observed on the cratonic margin of the central part of these shrinking basins were due to shifting of water masses resulting from the regressive process on the northern and southern margins. Comparison between the main stages of transgression and regression allows some quantification concerning velocities of displacement of coastlines, specifically lengthwise. The permanence of paleogeographic and structural features over the time argues for an indisputable tectonic heritage. In the dynamic framework of this typical barred retroarc basin where arc magmatic activity has contributed considerably to variation on sediment supply and changing bathymetry of the seaways connecting with the Pacific Ocean, evidence for an assumed global eustatic cycle remains questionable or very subordinated.

  6. Acceleration and novelty: community restoration speeds recovery and transforms species composition in Andean cloud forest. (United States)

    Wilson, Sarah Jane; Rhemtulla, Jeanine M


    Community-based tropical forest restoration projects, often promoted as a win-win solution for local communities and the environment, have increased dramatically in number in the past decade. Many such projects are underway in Andean cloud forests, which, given their extremely high biodiversity and history of extensive clearing, are understudied. This study investigates the efficacy of community-based tree-planting projects to accelerate cloud forest recovery, as compared to unassisted natural regeneration. This study takes place in northwest Andean Ecuador, where the majority of the original, highly diverse cloud forests have been cleared, in five communities that initiated tree-planting projects to restore forests in 2003. In 2011, we identified tree species along transects in planted forests (n = 5), naturally regenerating forests (n = 5), and primary forests (n = 5). We also surveyed 120 households about their restoration methods, tree preferences, and forest uses. We found that tree diversity was higher in planted than in unplanted secondary forest, but both were less diverse than primary forests. Ordination analysis showed that all three forests had distinct species compositions, although planted forests shared more species with primary forests than did unplanted forests. Planted forests also contained more animal-dispersed species in both the planted canopy and in the unplanted, regenerating understory than unplanted forests, and contained the highest proportion of species with use value for local people. While restoring forest increased biodiversity and accelerated forest recovery, restored forests may also represent novel ecosystems that are distinct from the region's previous ecosystems and, given their usefulness to people, are likely to be more common in the future.

  7. DNA Barcoding of an Assembly of Montane Andean Butterflies (Satyrinae): Geographical Scale and Identification Performance. (United States)

    Marín, M A; Cadavid, I C; Valdés, L; Álvarez, C F; Uribe, S I; Vila, R; Pyrcz, T W


    DNA barcoding is a technique used primarily for the documentation and identification of biological diversity based on mitochondrial DNA sequences. Butterflies have received particular attention in DNA barcoding studies, although varied performance may be obtained due to different scales of geographic sampling and speciation processes in various groups. The montane Andean Satyrinae constitutes a challenging study group for taxonomy. The group displays high richness, with more of 550 species, and remarkable morphological similarity among taxa, which renders their identification difficult. In the present study, we evaluated the effectiveness of DNA barcodes in the identification of montane Andean satyrines and the effect of increased geographical scale of sampling on identification performance. Mitochondrial sequences were obtained from 104 specimens of 39 species and 16 genera, collected in a forest remnant in the northwest Andes. DNA barcoding has proved to be a useful tool for the identification of the specimens, with a well-defined gap and producing clusters with unambiguous identifications for all the morphospecies in the study area. The expansion of the geographical scale with published data increased genetic distances within species and reduced those among species, but did not generally reduce the success of specimen identification. Only in Forsterinaria rustica (Butler, 1868), a taxon with high intraspecific variation, the barcode gap was lost and low support for monophyly was obtained. Likewise, expanded sampling resulted in a substantial increase in the intraspecific distance in Morpho sulkowskyi (Kollar, 1850); Panyapedaliodes drymaea (Hewitson, 1858); Lymanopoda obsoleta (Westwood, 1851); and Lymanopoda labda Hewitson, 1861; but for these species, the barcode gap was maintained. These divergent lineages are nonetheless worth a detailed study of external and genitalic morphology variation, as well as ecological features, in order to determine the potential

  8. Uptake of Hg2+ by picocyanobacteria in natural water from four Andean lakes

    Directory of Open Access Journals (Sweden)

    Diéguez M.C.


    Full Text Available In lake food webs, planktonic bacteria and algae represent the greatest bioconcentration step for Hg2+ and monomethyl-Hg (MeHg. As they are the most abundant organisms in planktonic trophic webs and also the main food resource for herbivorous plankton, they can mobilize large amounts of Hg to higher trophic levels. In Andean Patagonian lakes (Argentina, dissolved organic matter (DOM concentration and character, coupled with photo-reactions, play a central role in the complexation of Hg2+ in the water column and can even regulate the uptake of Hg2+ by planktonic algae. In this investigation we evaluated the DOM character of natural waters (NW from four Andean lakes and studied its influence on the uptake of 197Hg2+ in a strain of the picocyanobacteria Synechococcus by using Hg2+ labeled with 197Hg2+. The uptake of radiolabeled Hg2+ by Synechococcus showed different magnitude in NW of lakes Moreno, El Trébol, Morenito and Escondido. Increasing lake DOM concentration reduced the bioavailability of Hg2+ as indicated by the lower uptakes rates found in NW with higher complexity and concentration of the DOM pool. Uptakes of Hg2+ by this picocyanobacteria contrasted among NW from pelagic (surface and bottom and littoral compartments of Lake Escondido which suggest that the entry of this metal may be highly variable even in the same environment. The study of the uptake of radiolabeled Hg2+ in a set of dilutions of NW from Lake Escondido demonstrated that the bioavailability of Hg2+ decrease with increasing DOM concentration.

  9. Phlebotomine sandflies (Diptera: Psychodidae in a sub-Andean forest from the Norte de Santander, Colombia

    Directory of Open Access Journals (Sweden)

    Richard Hoyos-López


    Full Text Available Background & objectives: The recognition of communities of arthropods with medical importance in natural systems constitutes an important step in the prediction of possible epidemic events and/or emergence of infectious diseases in the human population. This is due to anthropogenic impact in natural areas and landscape modification, which changes the dynamics of pathogenic agents, reservoirs, and vector insects. In this study, an inventory was compiled of species of the genus Lutzomyia present in sub-Andean forest from the confluence of the Pamplonita River basin. Methods: CDC-light and Shannon traps were used for collecting adult phlebotomine sandflies during the month of October 2013 in a sub-Andean forest from river basin Pamplonita. All specimens were identified using morphological keys. The epidemiological relevance of each species was reported using a literature review about natural infection or vector incrimination with Leishmania species or other pathogens microorganism. Results: A total of 2755 specimens belonging to eight species of the genus Lutzomyia were collected. Out of the eight species, seven belonged to the group verrucarum (Lutzomyia sp - townsendi series, L. ovallesi, L. spinicrassa, L. serrana, L. townsendi, L. nuneztovari and L. pia, while one belonged to the subgenus Helcocyrtomyia (L. hartmanni. A new registry of L. townsendi was observed for the Norte de Santander department. Interpretation & conclusion: The appreciable diversity of the verrucarum group observed in this area suggest further investigation on the biogeography and evolution of this group, and epidemiological risk for human populations around this area, as there are reports of Leishmania natural infection and favourable conditions for domestication of phlebotomines in rural towns.

  10. Hydrological connectivity of alluvial Andean valleys: a groundwater/surface-water interaction case study in Ecuador (United States)

    Guzmán, Pablo; Anibas, Christian; Batelaan, Okke; Huysmans, Marijke; Wyseure, Guido


    The Andean region is characterized by important intramontane alluvial and glacial valleys; a typical example is the Tarqui alluvial plain, Ecuador. Such valley plains are densely populated and/or very attractive for urban and infrastructural development. Their aquifers offer opportunities for the required water resources. Groundwater/surface-water (GW-SW) interaction generally entails recharge to or discharge from the aquifer, dependent on the hydraulic connection between surface water and groundwater. Since GW-SW interaction in Andean catchments has hardly been addressed, the objectives of this study are to investigate GW-SW interaction in the Tarqui alluvial plain and to understand the role of the morphology of the alluvial valley in the hydrological response and in the hydrological connection between hillslopes and the aquifers in the valley floor. This study is based on extensive field measurements, groundwater-flow modelling and the application of temperature as a groundwater tracer. Results show that the morphological conditions of a valley influence GW-SW interaction. Gaining and losing river sections are observed in narrow and wide alluvial valley sections, respectively. Modelling shows a strong hydrological connectivity between the hillslopes and the alluvial valley; up to 92 % of recharge of the alluvial deposits originates from lateral flow from the hillslopes. The alluvial plain forms a buffer or transition zone for the river as it sustains a gradual flow from the hills to the river. Future land-use planning and development should include concepts discussed in this study, such as hydrological connectivity, in order to better evaluate impact assessments on water resources and aquatic ecosystems.

  11. Seismic imaging of the upper mantle beneath the northern Central Andean Plateau: Implications for surface topography (United States)

    Ward, K. M.; Zandt, G.; Beck, S. L.; Wagner, L. S.


    Extending over 1,800 km along the active South American Cordilleran margin, the Central Andean Plateau (CAP) as defined by the 3 km elevation contour is second only to the Tibetan Plateau in geographic extent. The uplift history of the 4 km high Plateau remains uncertain with paleoelevation studies along the CAP suggesting a complex, non-uniform uplift history. As part of the Central Andean Uplift and the Geodynamics of High Topography (CAUGHT) project, we use surface waves measured from ambient noise and two-plane wave tomography to image the S-wave velocity structure of the crust and upper mantle to investigate the upper mantle component of plateau uplift. We observe three main features in our S-wave velocity model including (1), a high velocity slab (2), a low velocity anomaly above the slab where the slab changes dip from near horizontal to a normal dip, and (3), a high-velocity feature in the mantle above the slab that extends along the length of the Altiplano from the base of the Moho to a depth of ~120 km with the highest velocities observed under Lake Titicaca. A strong spatial correlation exists between the lateral extent of this high-velocity feature beneath the Altiplano and the lower elevations of the Altiplano basin suggesting a potential relationship. Non-uniqueness in our seismic models preclude uniquely constraining this feature as an uppermost mantle feature bellow the Moho or as a connected eastward dipping feature extending up to 300 km in the mantle as seen in deeper mantle tomography studies. Determining if the high velocity feature represents a small lithospheric root or a delaminating lithospheric root extending ~300 km into the mantle requires more integration of observations, but either interpretation shows a strong geodynamic connection with the uppermost mantle and the current topography of the northern CAP.

  12. Genome-Wide Association Study of Anthracnose Resistance in Andean Beans (Phaseolus vulgaris.

    Directory of Open Access Journals (Sweden)

    Grady H Zuiderveen

    Full Text Available Anthracnose is a seed-borne disease of common bean (Phaseolus vulgaris L. caused by the fungus Colletotrichum lindemuthianum, and the pathogen is cosmopolitan in distribution. The objectives of this study were to identify new sources of anthracnose resistance in a diverse panel of 230 Andean beans comprised of multiple seed types and market classes from the Americas, Africa, and Europe, and explore the genetic basis of this resistance using genome-wide association mapping analysis (GWAS. Twenty-eight of the 230 lines tested were resistant to six out of the eight races screened, but only one cultivar Uyole98 was resistant to all eight races (7, 39, 55, 65, 73, 109, 2047, and 3481 included in the study. Outputs from the GWAS indicated major quantitative trait loci (QTL for resistance on chromosomes, Pv01, Pv02, and Pv04 and two minor QTL on Pv10 and Pv11. Candidate genes associated with the significant SNPs were detected on all five chromosomes. An independent QTL study was conducted to confirm the physical location of the Co-1 locus identified on Pv01 in an F4:6 recombinant inbred line (RIL population. Resistance was determined to be conditioned by the single dominant gene Co-1 that mapped between 50.16 and 50.30 Mb on Pv01, and an InDel marker (NDSU_IND_1_50.2219 tightly linked to the gene was developed. The information reported will provide breeders with new and diverse sources of resistance and genomic regions to target in the development of anthracnose resistance in Andean beans.

  13. Jiangxi Copper Plans to Increase its Refined Copper Output

    Institute of Scientific and Technical Information of China (English)


    <正>According to news published on March 30th, China’s largest copper producer--Jiangxi Copper alleged in its 2010 Financial Report Statement that it plans to improve its output of refined copper by 4.4% in 2011, to increase from 900,000 tonnes last year to 940,000 tons.

  14. Geochemical characteristics of the Shujiadian Cu deposit related intrusion in Tongling: Petrogenesis and implications for the formation of porphyry Cu systems in the Middle-Lower Yangtze River Valley metallogenic belt, eastern China (United States)

    Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; Cooke, David R.; Zhang, Lejun; Fu, Bin; White, Noel C.


    Porphyry Cu deposits can form in intracontinental or post-collision settings; however, both the genesis of fertile magmas and the mechanism of metal enrichment remain controversial. The Shujiadian porphyry Cu deposit is located in the Tongling area of the Middle-Lower Yangtze River Valley metallogenic belt. It is hosted by the Shujiadian complex, which mainly consists of quartz diorite porphyry (143.7 ± 1.7 Ma) and pyroxene diorite (139.8 ± 1.6 Ma). They both belong to the calc-alkaline series, with enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE), depletion in high field-strength elements (HFSE) and heavy rare earth elements (HREE), and slightly negative Eu anomalies. Both quartz diorite porphyry and pyroxene diorite have geochemical affinities with adakite, and their low MgO (1.5-3.7 wt%), and Ni (3.7-6.9 ppm), Cr (2.0-44 ppm), and Th/Ce contents (0.06-0.11) indicate that the intrusive rocks have some characteristics of adakite-like rocks derived from thickened lower crust and melts from metabasaltic rocks and eclogites. Plagioclases from the quartz diorite porphyry are andesine (An value = 31.8-40.5) and from the pyroxene diorite are felsic albite and oligoclase with large-scale zones and variable An value (An value = 8.9-18.3), Fe and Sr contents, which indicate that mixing of mafic and felsic magma may have occurred in the shallow magma chamber. Compared to the barren quartz diorite porphyry, relatively lower SiO2 contents (49.5-55.2 wt.%), higher εNd(t) values (- 7.4 to - 6.9), εHf(t) values (- 11.0 to - 9.1) compositions, Ti-in-zircon temperatures (714-785 °C), and variations of HREE contents of the mineralization-related pyroxene diorite suggest mixing with high-temperature mafic magma. Calculated Ce4 +/Ce3 + values of pyroxene diorite plot between the Ni-NiO buffer (NNO) and magnetite-hematite buffer (MH), and barren quartz diorite porphyry samples plot below the Ni-NiO buffer (NNO). Geochemical features of

  15. [Copper metabolism and genetic disorders]. (United States)

    Shimizu, Norikazu


    Copper is one of essential trace elements. Copper deficiency lead to growth and developmental failure and/or neurological dysfunction. However, excess copper is also problems for human life. There are two disorders of inborn error of copper metabolism, Menkes disease and Wilson disease. Menkes disease is an X linked recessive disorder with copper deficiency and Wilson disease is an autosomal recessive disorder with copper accumulation. These both disorders result from the defective functioning of copper transport P-type ATPase, ATP7A of Menkes disease and ATP7B of Wilson disease. In this paper, the author describes about copper metabolism of human, and clinical feature, diagnosis and treatment of Menkes disease and Wilson disease.

  16. Chinese Copper Manufacturers Expand Overseas

    Institute of Scientific and Technical Information of China (English)


    <正>In 2012,China’s apparent copper consumption reached 8.84 million tons,accounting for 43%of the global total demand.Spurred by strong demand,China’s copper smelting capacity roars with annual average growth in domestic copper smelting capacity reaching approx-

  17. Fabrication and Characterization of Metallic Copper and Copper Oxide Nanoflowers

    Directory of Open Access Journals (Sweden)

    *H. S. Virk


    Full Text Available Copper nanoflowers have been fabricated using two different techniques; electro-deposition of copper in polymer and anodic alumina templates, and cytyltrimethal ammonium bromide (CTAB-assisted hydrothermal method. Scanning Electron Microscope (SEM images record some interesting morphologies of metallic copper nanoflowers. Field Emission Scanning Electron Microscope (FESEM has been used to determine morphology and composition of copper oxide nanoflowers. X-ray diffraction (XRD pattern reveals the monoclinic phase of CuO in the crystallographic structure of copper oxide nanoflowers. There is an element of random artistic design of nature, rather than science, in exotic patterns of nanoflowers fabricated in our laboratory.

  18. Lead isotopic composition and lead source of the Tongchanghe basalt-type native copper-chalcocite deposit in Ninglang, western Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qian; ZHU Xiaoqing; ZHANG Zhengwei


    The Tongchanghe native copper-chalcocite deposit at Ninglang occurs in low-Ti basalts of western Yunnan, and the mode of fault-filling & metasomatism metallogenesis indicates that this deposit is of late-stage hydrothermal origin. This makes it more complicated to define the source of ore-forming materials. This paper introduces the Pb isotope data of Himalayan alkali-rich porphyries, regional Early-Middle Proterozoic metamorphic rock basement and various types of rocks of the mining district in western Yunnan with an attempt to constrain the origin of the Tongchanghe native copper-chalcocite deposit at Ninglang.The results showed that the ores are relatively homogeneous in Pb isotopic composition, implying a simple ore-forming material source. The three sets of Pb isotopic ratios in the Himalayan alkali-rich porphyries are all higher than those of the ores; the regional basement metamorphic rocks show a wide range of variations in Pb isotopic ratio, quite different from the isotopic composition of ore lead; the Pb isotopic composition of the Triassic sedimentary rocks and mudstone and siltstone interbeds in the Late Permian Heinishao Formation (corresponding to the forth cycle of basaltic eruption) in the mining district has the characteristics of radiogenic lead and is significantly different from the isotopic composition of ore lead; like the ores, the Emeishan basalts in the mining district and those regionally distributed possess the same Pb isotopic composition, showing a complete overlap with respect to their distribution range. From the above, the possibilities can be ruled out that the ore-forming materials of the Tongchanghe deposit were derived from the basement, a variety of Himalayan magmatic activities, etc. It is thereby defined that the ore-forming materials were derived largely from the Emeishan basalts. From the data available it is deduced that the native cupper-chalcocite-type metallogenesis that occurred in the Emeishan basalt-distributed area

  19. Copper and Copper Proteins in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Sergio Montes


    Full Text Available Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson’s disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson’s disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson’s disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson’s disease and that a mutation in ATP7B could be associated with Parkinson’s disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology.

  20. Industrial experiment of copper electrolyte purification by copper arsenite

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ya-jie; XIAO Fa-xin; WANG Yong; LI Chun-hua; XU Wei; JIAN Hong-sheng; MA Yut-ian


    Copper electrolyte was purified by copper arsenite that was prepared with As2O3. And electrolysis experiments of purified electrolyte were carried out at 235 and 305 A/m2, respectively. The results show that the yield of copper arsenite is up to 98.64% when the molar ratio of Cu to As is 1.5 in the preparation of copper arsenite. The removal rates of Sb and Bi reach 74.11% and 65.60% respectively after copper arsenite is added in electrolyte. The concentrations of As, Sb and Bi in electrolyte nearly remain constant during electrolysis of 13 d. The appearances of cathode copper obtained at 235 and 305 A/m2 are slippery and even, and the qualification rate is 100% according to the Chinese standard of high-pure cathode copper(GB/T467-97).

  1. Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S


    Liquid-based precursors for formation of Copper Selenide, Indium Selenide, Copper Indium Diselenide, and/or copper Indium Galium Diselenide include copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent. These liquid-based precursors can be deposited in liquid form onto substrates and treated by rapid thermal processing to form crystalline copper selenide and indium selenide films.

  2. Age constraints on the hydrothermal history of the Prominent Hill iron oxide copper-gold deposit, South Australia (United States)

    Bowden, Bryan; Fraser, Geoff; Davidson, Garry J.; Meffre, Sebastien; Skirrow, Roger; Bull, Stuart; Thompson, Jay


    The Mesoproterozoic Prominent Hill iron-oxide copper-gold deposit lies on the fault-bound southern edge of the Mt Woods Domain, Gawler Craton, South Australia. Chalcocite-bornite-chalcopyrite ores occur in a hematitic breccia complex that has similarities to the Olympic Dam deposit, but were emplaced in a shallow water clastic-carbonate package overlying a thick andesite-dacite pile. The sequence has been overturned against the major, steep, east-west, Hangingwall Fault, beyond which lies the clastic to potentially evaporitic Blue Duck Metasediments. Immediately north of the deposit, these metasediments have been intruded by dacite porphyry and granitoid and metasomatised to form magnetite-calc-silicate skarn ± pyrite-chalcopyrite. The hematitic breccia complex is strongly sericitised and silicified, has a large sericite ± chlorite halo, and was intruded by dykes during and after sericitisation. This paper evaluates the age of sericite formation in the mineralised breccias and provides constraints on the timing of granitoid intrusion and skarn formation in the terrain adjoining the mineralisation. The breccia complex contains fragments of granitoid and porphyry that are found here to be part of the Gawler Range Volcanics/Hiltaba Suite magmatic event at 1600-1570 Ma. This indicates that some breccia formation post-dated granitoid intrusion. Monazite and apatite in Fe-P-REE-albite metasomatised granitoid, paragenetically linked with magnetite skarn formation north of the Hangingwall Fault, grew soon after granitoid intrusion, although the apatite experienced U-Pb-LREE loss during later fluid-mineral interaction; this accounts for its calculated age of 1544 ± 39 Ma. To the south of the fault, within the breccia, 40Ar-39Ar ages yield a minimum age of sericitisation (+Cu+Fe+REE) of dykes and volcanics of ˜1575 Ma, firmly placing Prominent Hill ore formation as part of the Gawler Range Volcanics/Hiltaba Suite magmatic event within the Olympic Cu-Au province of the

  3. Analysis of Genetic Variability among thirty accessions of Andean Lupin (Lupinus mutabilis Sweet using ISSR molecular markers

    Directory of Open Access Journals (Sweden)

    Michelle C. Chirinos-Arias


    Full Text Available In order to make the genetic variability analysis among thirty accessions of andean lupine (L. mutabilis Sweet belonging to Agrarian Innovation National Institute (INIA Seed Bank. DNA was extracted from 300 plants and we made bulks. We standardized amplification protocol of Inter Simple Sequence Repeat (ISSR primers, we chose the most polymorphic primers to run in acrylamide gel. We found 255 ISSR loci with 8 primers. It was found high genetic variability of the samples under study by ISSR markers. Also observed relatively high polymorphism for autogamous species such as andean lupine. Finally phenograms showed a relationship with the geographical location, possibly due to in situ gene flow due to the exchange or sale of seeds in markets near the collection area.

  4. Creative Copper Crests (United States)

    Knab, Thomas


    In this article, the author discusses how to create an art activity that would link the computer-created business cards of fourth-grade students with an upcoming school-wide medieval event. Creating family crests from copper foil would be a great connection, since they, like business cards, are an individual's way to identify themselves to others.…

  5. Multiple Sulfate Isotopic Evidence on the Formation of Oxide Copper Ore at Spence, Atacama Desert, Northern Chile (United States)

    Sun, T.; Bao, H.; Reich, M.; Palacios, C.


    In the Atacama Desert of northern Chile, one of the world's richest metallogenic provinces, porphyry copper deposits are characterized by the unique occurrence of atacamite in their oxidized zones. The origin and formation of the oxide zone of these copper deposits is, however, controversial. It was proposed that Cl-rich deep formation water pumping-up events along faults by earthquakes, after onset of the hyperaridity, were required (Cameron et al., 2007). Their model would imply that supplies of saline deep formation water from fractures to the surface should have left behind a homogeneous or fracture-controlled salt profile from surface down to the oxide zone. While no excluding the deep formation water model in other deposit, here we propose that, in our sampling region, the alternative saline source, which is critical for atacamite formation, could be locally evaporated groundwater, Cl-rich salts leached from arid surface by meteoric water, or brines from eastern salar basins at a time when the climate in northern Chile was changing from arid to hyperarid. At this climate transition, arid- requiring minerals such as atacamite in the oxide zone were formed and, more importantly, preserved upon evaporation beneath the surface alluvial deposits. Since salt accumulation at the surface remain active during hyperarid condition, our model would predict that water-soluble salt profile from surface to the oxide zone should have a characteristic pattern: salts with an atmospheric component on the surface gradually transitioning to salts of the oxide ore zone on the bottom and a mixing zone in between. To test these two alternative models, we focus on sulfate salts, one of the common water-soluble salts in arid environments. An added advantage is that sulfate accumulated on desert surface has a secondary atmospheric component that bears a unique triple oxygen isotope signature, easily distinguishable from sulfate formed by the oxidation of sulfide minerals at the oxide

  6. Presenilin promotes dietary copper uptake.

    Directory of Open Access Journals (Sweden)

    Adam Southon

    Full Text Available Dietary copper is essential for multicellular organisms. Copper is redox active and required as a cofactor for enzymes such as the antioxidant Superoxide Dismutase 1 (SOD1. Copper dyshomeostasis has been implicated in Alzheimer's disease. Mutations in the presenilin genes encoding PS1 and PS2 are major causes of early-onset familial Alzheimer's disease. PS1 and PS2 are required for efficient copper uptake in mammalian systems. Here we demonstrate a conserved role for presenilin in dietary copper uptake in the fly Drosophila melanogaster. Ubiquitous RNA interference-mediated knockdown of the single Drosophila presenilin (PSN gene is lethal. However, PSN knockdown in the midgut produces viable flies. These flies have reduced copper levels and are more tolerant to excess dietary copper. Expression of a copper-responsive EYFP construct was also lower in the midgut of these larvae, indicative of reduced dietary copper uptake. SOD activity was reduced by midgut PSN knockdown, and these flies were sensitive to the superoxide-inducing chemical paraquat. These data support presenilin being needed for dietary copper uptake in the gut and so impacting on SOD activity and tolerance to oxidative stress. These results are consistent with previous studies of mammalian presenilins, supporting a conserved role for these proteins in mediating copper uptake.

  7. Evaluation of indigenous grains from the Peruvian Andean region for antidiabetes and antihypertension potential using in vitro methods. (United States)

    Ranilla, Lena Galvez; Apostolidis, Emmanouil; Genovese, Maria Ines; Lajolo, Franco Maria; Shetty, Kalidas


    The health-relevant functionality of 10 thermally processed Peruvian Andean grains (five cereals, three pseudocereals, and two legumes) was evaluated for potential type 2 diabetes-relevant antihyperglycemia and antihypertension activity using in vitro enzyme assays. Inhibition of enzymes relevant for managing early stages of type 2 diabetes such as hyperglycemia-relevant alpha-glucosidase and alpha-amylase and hypertension-relevant angiotensin I-converting enzyme (ACE) were assayed along with the total phenolic content, phenolic profiles, and antioxidant activity based on the 1,1-diphenyl-2-picrylhydrazyl radical assay. Purple corn (Zea mays L.) (cereal) exhibited high free radical scavenging-linked antioxidant activity (77%) and had the highest total phenolic content (8 +/- 1 mg of gallic acid equivalents/g of sample weight) and alpha-glucosidase inhibitory activity (51% at 5 mg of sample weight). The major phenolic compound in this cereal was protocatechuic acid (287 +/- 15 microg/g of sample weight). Pseudocereals such as Quinoa (Chenopodium quinoa Willd) and Kañiwa (Chenopodium pallidicaule Aellen) were rich in quercetin derivatives (1,131 +/- 56 and 943 +/- 35 microg [expressed as quercetin aglycone]/g of sample weight, respectively) and had the highest antioxidant activity (86% and 75%, respectively). Andean legumes (Lupinus mutabilis cultivars SLP-1 and H-6) inhibited significantly the hypertension-relevant ACE (52% at 5 mg of sample weight). No alpha-amylase inhibitory activity was found in any of the evaluated Andean grains. This in vitro study indicates the potential of combination of Andean whole grain cereals, pseudocereals, and legumes to develop effective dietary strategies for managing type 2 diabetes and associated hypertension and provides the rationale for animal and clinical studies.

  8. Stable isotope variations (δ18O and δD) in modern waters across the Andean Plateau (United States)

    Bershaw, John; Saylor, Joel E.; Garzione, Carmala N.; Leier, Andrew; Sundell, Kurt E.


    Environmental parameters that influence the isotopic composition of meteoric water (δ18O and δD) are well characterized up the windward side of mountains, where orographic precipitation results in a predictable relationship between the isotopic composition of precipitation and elevation. The topographic and climatic evolution of the Andean Plateau and surrounding regions has been studied extensively by exploiting this relationship through the use of paleowater proxies. However, interpretation on the plateau itself is challenged by a poor understanding of processes that fractionate isotopes during vapor transport and rainout, and by the relative contribution of unique moisture sources. Here, we present an extensive dataset of modern surface water samples for the northern Andean Plateau and surrounding regions to elucidate patterns and causes of isotope fractionation in this continental environment. These data show a progressive increase in δ18O of stream water west of the Eastern Cordillera (∼1‰/70 km), almost identical to the rate observed across the Tibetan Plateau, attributed to a larger fraction of recycled water in precipitation and/or increased evaporative enrichment downwind. This may lead to underestimates of paleoelevation, particularly for sites deep into the rainshadow of the Eastern Cordilleran crest. That said, elevation is a primary control on the isotopic composition of surface waters across the entire Andean Plateau and its flanks when considering the most negative δ18O values, highlighting the need for sufficiently large datasets to distinguish minimally evaporated samples. There is a general increase in δ18O on the plateau from north to south, concomitant with an increase in aridity and decrease in convective moistening (amount effect). Lastly, stable isotope and seasonal precipitation patterns suggest easterlies provide the vast majority of moisture that falls as precipitation across the Andean Plateau and Western Cordillera, from Peru to

  9. Variability in New Shortening Estimates from Southern Peru (12-14S); Implications for Mass Balance of the Andean Plateau. (United States)

    Gotberg, N.; McQuarrie, N.


    One of the fundamental questions of interest with regards to the Andean Plateau is the mass balance of material needed to create and sustain a 3-4 km high plateau. Is crustal shortening sufficient to support an isostatically compensated crust of 60-70km? We present new estimates of shortening across the northern margin of the Andean Plateau. The cross section extent, from the eastern edge of the volcanic arc to foreland basin, is approximately one half of the physiographic width of the Andean Plateau in Peru. Cross sectional shortening estimates in southern Peru (12-14°S) provide a best estimate of 123 km or 40% shortening with an absolute minimum estimate of 86 km or 30% and absolute maximum estimate of 275 km or 60%. We determined the maximum and minimum shortening estimates using the cross sectional area and possible variations in assumptions made about the amount of erosion, detachment dip, involvement of basement thrusts and displacement along faults. The best estimate of shortening is well short of the required 240-300km of shortening needed in order to account for a 60-70km thick crust under the entire plateau. This suggests that for an isostatically equilibrated crust either 1) there is a significant amount of shortening (~150km) in the western half of the plateau which, is hidden by the volcanic arc or 2) crustal material is being added to the Peruvian section of the Andean Plateau either through lower crustal flow or a process of magmatic underplating followed by differentiation and delamination.

  10. Improving glacier volume-area scaling to better quantify tropical Andean glacial water resources from remote sensing (United States)

    Klein, A. G.; Kincaid, J. L.; Dobreva, I. D.


    Tropical glaciers are an important component of the water budget for high-altitude catchments in much of the central Andes. The majority of tropical Andean glaciers are small, but it has been suggested that because of their numbers the volume of water they contain is significant. Unfortunately, the ice volume measurements needed to inform decision makers have been made for only a handful of tropical glaciers. In August 2012, with the assistance of the Instituto Geográfico Militar in Bolivia, ground penetrating radar (GPR) and differential Global Positioning System (dGPS) measurements were collected along transects totaling 3,189 m in length on the Charquini SE cirque glacier. This small cirque glacier which is located in the southern portion of the Cordillera Real in Bolivia had an approximate surface area in 2012 of 02.42 square kilometers. Our initial observations indicate that the GPR survey was able to adequately capture the ice bedrock interface. Ordinary Kriging was used to develop maps of surface and subsurface topography from the dGPS and GPR observations. In 2012, the Charquini SE glacier contained a minimum of 3,900,000 cubic meters of ice. This information, along with other recent volume measurements for tropical and sub-tropical Andean glaciers, was used to update earlier volume-area scaling relationships established for these glaciers. This relationship will then be applied to determine the volume of water currently stored in tropical Andean glaciers based on previous research on glaciers areas using remote sensing.

  11. Two-types of Early Cretaceous adakitic porphyries from the Luxi terrane, eastern North China Block: Melting of subducted Paleo-Pacific slab and delaminated newly underplated lower crust (United States)

    Wang, Hao; Xu, Zhaowen; Lu, Xiancai; Fu, Bin; Lu, Jianjun; Yang, Xiaonan; Zhao, Zengxia


    The origin and tectonic setting of Early Cretaceous adakitic rocks from the Luxi terrane in the eastern North China Block (NCB) remain debated. To resolve this issue, we determined whole-rock geochemistry, zircon U-Pb ages, and in situ Hf-O isotopes of the Mengyin and Liujing adakitic porphyries from the Luxi terrane. Zircon U-Pb dating results reveal that both the Mengyin and Liujing plutons were emplaced during the Early Cretaceous, with weighted mean 206Pb/238U ages of 130 ± 1 Ma (2σ) and 131 ± 2 Ma (2σ), respectively. In addition, abundant Neoarchean-Paleoproterozoic inherited zircon cores are identified in the Mengyin adakitic porphyry with 207Pb/206Pb ages ranging from 2.53 to 2.42 Ga. Rocks of both plutons are silicic (SiO2 = 65.4-70.2 wt.%), metaluminous, and alkaline in composition, comprising mainly quartz syenite porphyries. Samples from both plutons are enriched in large ion lithophile elements (LILEs) (e.g., Rb, Sr, and Ba), and light rare earth elements (LREEs), depleted in high field strength elements (HFSEs) (e.g., Nb, Ta, and Ti), and heavy rare earth elements (HREEs), and have either positive or no Eu anomalies. In addition, both adakitic porphyries have high Mg# values (51-64), high Sr and La contents, low Y and Yb contents, and high Sr/Y (Mengyin = 149-264; Liujing = 58-110) and (La/Yb)N (Mengyin = 32.4-45.3; Liujing = 43.8-53.1) ratios, similar to adakitic rocks worldwide. The Mengyin adakitic porphyry has higher whole-rock εNd(t) values (-5.8 to - 4.1), more radiogenic Pb [(206Pb/204Pb)i = 18.35-18.39, (207Pb/204Pb)i = 15.55-15.56, (208Pb/204Pb)i = 38.20-38.23], higher zircon rim εHf(t) values (+ 3.3 to + 8.8) and δ18O values (+ 6.5‰ to + 7.9‰), and lower (87Sr/86Sr)i ratios (0.7049-0.7050) than the Liujing adakitic porphyry [εNd(t) = - 12.4 to - 12.2, (206Pb/204Pb)i = 17.63-17.72, (207Pb/204Pb)i = 15.56-15.58, (208Pb/204Pb)i = 37.76-37.94, εHf(t) = - 14.8 to - 11.2, δ18O = + 5.9‰ to + 7.1‰, (87Sr/86Sr)i = 0.7090-0.7091]. The

  12. Comparative characteristics of copper, copper chloride, and copper bromide vapor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Kazarian, M.A.; Petrash, G.G.; Trofimov, A.N.


    The paper reports the results of a comparative study of copper and copper halide vapor lasers emitting in a repetitively-pulsed regime. Copper chloride and copper bromide vapor lasers are found to have identical lasing characteristics under any excitation conditions. These characteristics are different from those of a copper vapor laser. An average lasing power of 13 W has been obtained for all lasers studied for an efficiency of 1%. It is shown that the choice of a laser will largely depend on the laser design suitability for a specific application.

  13. Dark Adaptation at High Altitude: An Unexpected Pupillary Response to Chronic Hypoxia in Andean Highlanders. (United States)

    Healy, Katherine; Labrique, Alain B; Miranda, J Jaime; Gilman, Robert H; Danz, David; Davila-Roman, Victor G; Huicho, Luis; León-Velarde, Fabiola; Checkley, William


    Healy, Katherine, Alain B. Labrique, J. Jaime Miranda, Robert H. Gilman, David Danz, Victor G. Davila-Roman, Luis Huicho, Fabiola León-Velarde, and William Checkley. Dark adaptation at high altitude: an unexpected pupillary response to chronic hypoxia in Andean highlanders. High Alt Med Biol. 17:208-213, 2016.-Chronic mountain sickness is a maladaptive response to high altitude (>2500 m above sea level) and is characterized by excessive erythrocytosis and hypoxemia resulting from long-term hypobaric hypoxia. There is no known early predictor of chronic mountain sickness and the diagnosis is based on the presence of excessive erythrocytosis and clinical features. Impaired dark adaptation, or an inability to visually adjust from high- to low-light settings, occurs in response to mild hypoxia and may serve as an early predictor of hypoxemia and chronic mountain sickness. We aimed to evaluate the association between pupillary response assessed by dark adaptometry and daytime hypoxemia in resident Andean highlanders aged ≥35 years living in Puno, Peru. Oxyhemoglobin saturation (SpO2) was recorded using a handheld pulse oximeter. Dark adaptation was quantitatively assessed as the magnitude of pupillary contraction to light stimuli of varying intensities (-2.9 to 0.1 log-cd/m(2)) using a portable dark adaptometer. Individual- and stimulus-specific multilevel analyses were conducted using mixed-effect models to elicit the relationship between SpO2 and pupillary responsiveness. Among 93 participants, mean age was 54.9 ± 11.0 years, 48% were male, 44% were night blind, and mean SpO2 was 89.3% ± 3.4%. The magnitude of pupillary contraction was greater with lower SpO2 (p dark-adapted conditions was exaggerated with hypoxemia and may serve as an early predictor of chronic mountain sickness. This unexpected association is potentially explained as an excessive and unregulated sympathetic response to hypoxemia at altitude.

  14. Geochemical variations in the Quaternary Andean back-arc volcanism, southern Mendoza, Argentina (United States)

    Espanon, Venera R.; Chivas, Allan R.; Kinsley, Leslie P. J.; Dosseto, Anthony


    The Payenia Basaltic Province (PBP) is located 450 km east of the Chile-Peru trench in central west Argentina, behind the Andean arc front, constituting the back-arc. In order to evaluate the influence of the subducting slab as well as the magmatic source of this region, two volcanic fields located at comparable distance to the trench, having abundant basaltic products and similar eruptive timeframes were chosen. The Llancanelo (LLVF) and the Payún Matrú (PMVF) volcanic fields are part of the PBP and exhibit abundant basaltic activity during the Pleistocene. The geochemical data suggest that the LLVF has some arc signatures which have been described as weak as they are not as pronounced as in the Andean arc. The weak arc signature is not derived from slab dehydration as high Th enrichment relative to U cannot be explained by this process. We relate the Th enrichment as well as the lack of large residual garnet signatures, to slab sediments in the source. In the case of the PMVF, no arc signature has been inferred despite being only 30 km south of the LLVF. However the PMVF has a composition similar to that of the local intraplate end member, represented by the Rio Colorado volcanic field. The two volcanic fields, LLVF and PMVF, show indications of lower crustal assimilation as they trend towards the lower continental crust end member in Nb/U vs Ce/Pb and Nb/Yb vs Th/Yb diagrams. The geochemical differences between the LLVF and the PMVF as well as between several volcanic fields are illustrated using spatial distribution maps of geochemical ratios. Using this new approach, the decrease in arc signature can be traced in the back-arc and the higher enrichment in high field strength elements (HFSE) relative to large ion lithophile elements (LILE) in the PMVF compared to the LLVF is explicitly shown. These geospatial maps provide a graphical manner to illustrate the presence of two distinct types of volcanism (OIB-like and arc-like) occurring in the same Quaternary

  15. Climatic and lacustrine morphometric controls of diatom paleoproductivity in a tropical Andean lake (United States)

    Bao, R.; Hernández, A.; Sáez, A.; Giralt, S.; Prego, R.; Pueyo, J. J.; Moreno, A.; Valero-Garcés, B. L.


    The coupling of lake dynamics with catchment biogeochemistry is considered the key element controlling primary production in mountain lakes at time scales of a few decades to millennia, yet little is known on the impacts of the morphometry of lakes throughout their ontogeny. As Lake Chungará (Central Andean Altiplano, northern Chile) experienced long-term lake-level fluctuations that strongly modified its area:volume ratio, it is an ideal system for exploring the relative roles that long-term climatic shifts and lake morphometry play on biosiliceous lacustrine productivity. In this paper, we review previous data on the percent contents of total organic carbon, total inorganic carbon, total nitrogen, total biogenic silica, isotopic composition of organic matter, carbonates, and diatom frustules, as well as data on the abundance of the chlorophycean Botryococcus braunii in this lake for the period 12,400-1300 cal yr BP. We also include new data on organic carbon and biogenic silica mass accumulation rates and the diatom assemblage composition of an offshore core dated using 14C and U/Th. Biosiliceous productivity in Lake Chungará was influenced by shifts in allochthonous nutrient inputs related to variability in precipitation. Humid phases dated at approx. 12,400 to 10,000 and 9600 to 7400 cal yr BP coincide with periods of elevated productivity, whereas decreases in productivity were recorded during arid phases dated at approx. 10,000 to 9600 and 7400 to 3550 cal yr BP (Andean mid-Holocene Aridity Period). However, morphometry-related in-lake controls led to a lack of a linear response of productivity to precipitation variability. During the late Glacial to early Holocene, lowstands facilitated complete water column mixing, prompting episodic massive blooms of a large centric diatom, Cyclostephanos cf. andinus. Thus, moderate productivity could be maintained, regardless of aridity, by this phenomenon of morphometric eutrophy during the early history of the lake

  16. Production of ultrahigh purity copper using waste copper nitrate solution. (United States)

    Choi, J Y; Kim, D S


    The production of ultrahigh purity copper (99.9999%) by electrolysis in the presence of a cementation barrier has been attempted employing a waste nitric copper etching solution as the electrolyte. The amount of copper deposited on the cathode increased almost linearly with electrolysis time and the purity of copper was observed to increase as the electrolyte concentration was increased. At some point, however, as the electrolyte concentration increased, the purity of copper decreased slightly. As the total surface area of cementation barrier increased, the purity of product increased. The electrolyte temperature should be maintained below 35 degrees C in the range of investigated electrolysis conditions to obtain the ultrahigh purity copper. Considering that several industrial waste solutions contain valuable metallic components the result of present study may support a claim that electrowinning is a very desirable process for their treatment and recovery.

  17. Tongling:Copper Industry Giant Takes Shape

    Institute of Scientific and Technical Information of China (English)


    <正>Centering on the strategic goal of building "World Copper Capital", Tongling constantly extends its product lines and improves the copper industry chain. Now, the copper industry with a production value of RMB 100 billion has taken shape.As the largest copper wire rod manufacturer in Asia, Tongling Quanwei Copper Technologies Co., Ltd., upon its moving into the local market,

  18. Human impact on the hydrology of the Andean páramos (United States)

    Buytaert, Wouter; Célleri, Rolando; De Bièvre, Bert; Cisneros, Felipe; Wyseure, Guido; Deckers, Jozef; Hofstede, Robert


    This paper analyses the problems involved in the conservation and management of the hydrological system of the South American páramo. The páramo consists of a collection of neotropical alpine grassland ecosystems covering the upper region of the northern Andes. They play a key role in the hydrology of the continent. Many of the largest tributaries of the Amazon basin have their headwaters in the páramo. It is also the major water source for the Andean highlands and a vast area of arid and semi-arid lowlands, where páramo water is used for domestic, agricultural and industrial consumption, and the generation of hydropower. Recently, the páramo is increasingly used for intensive cattle grazing, cultivation, and pine planting, among others. These activities, as well as global phenomena such as climate change, severely alter the hydrological regime. A review on the state of knowledge of its hydrology is given in a first part. In a second part, the impact of human activities and climate change on the hydrology of the páramo is discussed.

  19. Diversification of the rainfrog Pristimantis ornatissimus in the lowlands and Andean foothills of Ecuador (United States)

    Hutter, Carl R.; Tapia, Elicio E.; Culebras, Jaime; Peñafiel, Nicolás; Pyron, R. Alexander; Morochz, Carlos; Funk, W. Chris; Arteaga, Alejandro


    Geographic barriers and elevational gradients have long been recognized as important in species diversification. Here, we illustrate an example where both mechanisms have shaped the genetic structure of the Neotropical rainfrog, Pristimantis ornatissimus, which has also resulted in speciation. This species was thought to be a single evolutionary lineage distributed throughout the Ecuadorian Chocó and the adjacent foothills of the Andes. Based on recent sampling of P. ornatissimus sensu lato, we provide molecular and morphological evidence that support the validity of a new species, which we name Pristimantis ecuadorensis sp. nov. The sister species are elevational replacements of each other; the distribution of Pristimantis ornatissimus sensu stricto is limited to the Ecuadorian Chocó ecoregion (< 1100 m), whereas the new species has only been found at Andean localities between 1450–1480 m. Given the results of the Multiple Matrix Regression with Randomization analysis, the genetic difference between P. ecuadorensis and P. ornatissimus is not explained by geographic distance nor environment, although environmental variables at a finer scale need to be tested. Therefore this speciation event might be the byproduct of stochastic historic extinction of connected populations or biogeographic events caused by barriers to dispersal such as rivers. Within P. ornatissimus sensu stricto, morphological patterns and genetic structure seem to be related to geographic isolation (e.g., rivers). Finally, we provide an updated phylogeny for the genus, including the new species, as well as other Ecuadorian Pristimantis. PMID:28329011

  20. A new species of Andean poison frog, Andinobates (Anura: Dendrobatidae), from the northwestern Andes of Colombia. (United States)

    Amézquita, Adolfo; Márquez, Roberto; Medina, Ricardo; Mejía-Vargas, Daniel; Kahn, Ted R; Suárez, Gustavo; Mazariegos, Luis


    The poison frogs of the Colombian Andes, Pacific lowlands and Panama have been recently recognized as a new, monophyletic and well-supported genus: Andinobates. The species richness and distribution within Andinobates remain poorly understood due to the paucity of geographic, genetic and phenotypic data. Here we use a combination of molecular, bioacoustic and morphometric evidence to describe a new species of Andean poison frog: Andinobates cassidyhornae sp. nov. from the high elevation cloud forests of the Colombian Cordillera Occidental, in the northwestern Andes. The new species is associated to the bombetes group and characterized by a unique combination of ventral and dorsal color patterns. Data on 1119 bp from two mitochondrial markers allowed us to reject the null hypotheses that A. cassidyhornae sp. nov. is part of the phenotypically similar and geographically less distant species: A. opisthomelas, A. virolinensis or A. bombetes. The best available phylogenetic trees and the genetic distance to other Andinobates species further support this decision. Altogether, the advertisement call parameters unambiguously separated A. cassidyhornae sp. nov. calls from the calls of the three closest species. The new species adds to a poorly known and highly endangered genus of poison frogs that requires further studies and urgent conservation measures.

  1. Investigation Into the Humaneness of Slaughter Methods for Guinea Pigs (Cavia porcelus) in the Andean Region. (United States)

    Limon, Georgina; Gonzales-Gustavson, Eloy A; Gibson, Troy J


    Guinea pigs (Cavia porcelus) are an important source of nonhuman animal protein in the Andean region of South America. Specific guidelines regarding the welfare of guinea pigs before and during slaughter have yet to be developed. This study critically assessed the humaneness of 4 different stunning/slaughter methods for guinea pigs: cervical neck dislocation (n = 60), electrical head-only stunning (n = 83), carbon dioxide (CO2) stunning (n = 21), and penetrating captive bolt (n = 10). Following cervical neck dislocation, 97% of guinea pigs had at least 1 behavioral or cranial/spinal response. Six percent of guinea pigs were classified as mis-stunned after electrical stunning, and 1% were classified as mis-stunned after captive bolt. Increased respiratory effort was observed during CO2 stunning. Apart from this finding, there were no other obvious behavioral responses that could be associated with suffering. Of the methods assessed, captive bolt was deemed the most humane, effective, and practical method of stunning guinea pigs. Cervical neck dislocation should not be recommended as a slaughter method for guinea pigs.

  2. Cliffs used as communal roosts by Andean condors protect the birds from weather and predators.

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    Sergio A Lambertucci

    Full Text Available The quality and availability of resources influence the geographical distribution of species. Social species need safe places to rest, meet, exchange information and obtain thermoregulatory benefits, but those places may also serve other important functions that have been overlooked in research. We use a large soaring bird that roosts communally in cliffs, the Andean condor (Vultur gryphus, as a model species to elucidate whether roost locations serve as a refuge from adverse weather conditions (climatic refuge hypothesis, CRH, and/or from predators or anthropogenic disturbances (threats refuge hypothesis, TRH. The CRH predicts that communal roosts will face in the opposite direction from where storms originate, and will be located in climatically stable, low precipitation areas. The TRH predicts that communal roosts will be large, poorly accessible cliffs, located far from human-made constructions. We surveyed cliffs used as communal roosts by condors in northwestern Patagonia, and compared them with alternative non-roosting cliffs to test these predictions at local and regional scales. We conclude that communal roosting places provide refuge against climate and disturbances such as, for instance, the threats of predators (including humans. Thus, it is not only the benefits gained from being aggregated per se, but the characteristics of the place selected for roosting that may both be essential for the survival of the species. This should be considered in management and conservation plans given the current scenario of global climate change and the increase in environmental disturbances.

  3. Whole-Genome Sequencing Uncovers the Genetic Basis of Chronic Mountain Sickness in Andean Highlanders (United States)

    Zhou, Dan; Udpa, Nitin; Ronen, Roy; Stobdan, Tsering; Liang, Junbin; Appenzeller, Otto; Zhao, Huiwen W.; Yin, Yi; Du, Yuanping; Guo, Lixia; Cao, Rui; Wang, Yu; Jin, Xin; Huang, Chen; Jia, Wenlong; Cao, Dandan; Guo, Guangwu; Gamboa, Jorge L.; Villafuerte, Francisco; Callacondo, David; Xue, Jin; Liu, Siqi; Frazer, Kelly A.; Li, Yingrui; Bafna, Vineet; Haddad, Gabriel G.


    The hypoxic conditions at high altitudes present a challenge for survival, causing pressure for adaptation. Interestingly, many high-altitude denizens (particularly in the Andes) are maladapted, with a condition known as chronic mountain sickness (CMS) or Monge disease. To decode the genetic basis of this disease, we sequenced and compared the whole genomes of 20 Andean subjects (10 with CMS and 10 without). We discovered 11 regions genome-wide with significant differences in haplotype frequencies consistent with selective sweeps. In these regions, two genes (an erythropoiesis regulator, SENP1, and an oncogene, ANP32D) had a higher transcriptional response to hypoxia in individuals with CMS relative to those without. We further found that downregulating the orthologs of these genes in flies dramatically enhanced survival rates under hypoxia, demonstrating that suppression of SENP1 and ANP32D plays an essential role in hypoxia tolerance. Our study provides an unbiased framework to identify and validate the genetic basis of adaptation to high altitudes and identifies potentially targetable mechanisms for CMS treatment. PMID:23954164

  4. Large-scale patterns of turnover and Basal area change in Andean forests.

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    Selene Báez

    Full Text Available General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century.

  5. The Corregidores of the Colca Valley, Peru: Imperial Administration in an Andean Region

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    Cook, Noble David


    Full Text Available The corregidor de los indios was introduced into the Viceroyalty of Peru by Governor García de Castro in 1565. The institution was designed to limit the power of the encomendero elite and to improve administration and justice in the Andean countryside. Here we examine the impact of the reforms at the local level, the corregimiento of Los Collaguas in the Colca Valley, located between Cuzco and Arequipa. Althought the Crown was largely successful in weakening the encomienda, possibility of graft corrupted all but a handful of corregidores. The residencia did check some of those abuses.

    El gobernador García de Castro fue quien introdujo (1565 el corregidor de los indios en el virreinato del Perú. El corregimiento fue establecido para limitar el poder de los encomenderos y mejorar la administración y la justicia en los sitios rurales, y al mismo tiempo incrementar la colección del tributo. En este trabajo examinamos el impacto de las reformas en el corregimiento de los Collaguas situado en el hermoso valle del río Colca entre Arequipa y Cuzco. Aunque la corona fue más exitosa en debilitar la encomienda, la posibilidad de soborno corrompió a la mayoría de los corregidores.

  6. Phytosynthesis of gold nanoparticles using Andean Ajı′ (Capsicum baccatum L.

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    Brajesh Kumar


    Full Text Available This article covers the importance of Andean Ajı′/Chilli (Capsicum baccatum L. mediated synthesis of gold nanoparticles (AuNPs, which favors for green chemistry and escape us from the use of hazardous chemicals. UV–visible spectroscopy was used to monitor the quantitative formation of AuNPs. Further, as synthesized AuNPs were characterized using Transmission electron microscopy, Dynamic Light Scattering, and X-ray diffraction. It produced spherical AuNPs at λmax = 540 nm of average size 23.9 ± 9.7 nm without any aggregation. Ajı′ extract (aq was the good reducing and capping agent in terms of conversion to Au3+ to AuNPs. The synthesized AuNPs, also enhancing the photocatalytic degradation of methylene blue (>50%, k = 1.9585 × 10−3 min−1 under direct solar light irradiation. In addition, the experimental approach is benign, ecofriendly, and inexpensive for industrial-scale production of nanoparticles using Aji extract as natural bioreductant.

  7. A Re-Appraisal of the Early Andean Human Remains from Lauricocha in Peru (United States)

    Kuzminsky, Susan; Rohland, Nadin; Santos, Fabrício R.; Kaulicke, Peter; Valverde, Guido; Richards, Stephen M.; Nordenfelt, Susanne; Seidenberg, Verena; Mallick, Swapan; Cooper, Alan; Reich, David; Haak, Wolfgang


    The discovery of human remains from the Lauricocha cave in the Central Andean highlands in the 1960’s provided the first direct evidence for human presence in the high altitude Andes. The skeletons found at this site were ascribed to the Early to Middle Holocene and represented the oldest known population of Western South America, and thus were used in several studies addressing the early population history of the continent. However, later excavations at Lauricocha led to doubts regarding the antiquity of the site. Here, we provide new dating, craniometric, and genetic evidence for this iconic site. We obtained new radiocarbon dates, generated complete mitochondrial genomes and nuclear SNP data from five individuals, and re-analyzed the human remains of Lauricocha to revise the initial morphological and craniometric analysis conducted in the 1960’s. We show that Lauricocha was indeed occupied in the Early to Middle Holocene but the temporal spread of dates we obtained from the human remains show that they do not qualify as a single contemporaneous population. However, the genetic results from five of the individuals fall within the spectrum of genetic diversity observed in pre-Columbian and modern Native Central American populations. PMID:26061688

  8. Karyotypic variation in the Andean rodent Phyllotisxanthopygus (Waterhouse, 1837) (Rodentia, Cricetidae, Sigmodontinae). (United States)

    Labaroni, Carolina Alicia; Malleret, Matías Maximiliano; Novillo, Agustina; Ojeda, Agustina; Rodriguez, Daniela; Cuello, Pablo; Ojeda, Ricardo; Dardo Martí; Lanzone, Cecilia


    Phyllotisxanthopygus (Waterhouse, 1837) is an Andean rodent endemic to South America. Despite its wide geographical distribution in Argentina, few individuals have been studied on the cytogenetic level and only through conventional staining. In this work, chromosome characterization of Argentine samples of this species was performed using solid staining, C-banding and base-specific fluorochromes. Twenty two specimens were analyzed, collected in the provinces of Jujuy, Catamarca, and the north and south of Mendoza. All studied specimens showed 2n=38, having mostly the bi-armed autosomes, metacentric or submetacentric. Fundamental Number varied between 70 and 72. These changes were due to the presence of chromosome heteromorphisms in individuals from southern Mendoza and Jujuy. C-banding revealed pericentromeric blocks of constitutive heterochromatin in most chromosomes. Acrocentric chromosomes involved in heteromorphisms showed high variation in the amount of heterochromatin within and among populations. Additionally, banding with fluorochromes (DAPI and chromomycin A3) revealed homologous localization of AT and GC rich regions among chromosomes of the different populations analyzed. Comparisons among heteromorphic pairs suggested, however, that the variation might be the result of complex chromosome rearrangements, involving possibly amplifications and/or deletions of heterochromatic segments. These results are in accordance with molecular studies that indicate genetic variability within and among the populations of this taxon.

  9. Transplacental nutrient transfer during gestation in the Andean lizard Mabuya sp. (Squamata, Scincidae). (United States)

    Ramírez-Pinilla, Martha Patricia; Rueda, Elkin Darío; Stashenko, Elena


    Mabuya skinks have the most specialized allantoplacenta and the greatest degree of placentotrophy known among the Reptilia. Their recently ovulated eggs are microlecithal (1-2 mm) and lack fatty yolk platelets; thus, virtually all of the nutrients for embryonic development must pass across the placenta. We quantified the net uptake of nutrients during gestation in an Andean population of Mabuya and compared these results with other matrotrophic skinks and eutherian mammals. Total dry and wet masses, ash and organic content, ions (calcium, potassium, sodium, magnesium, iron), lipids (cholesterol, vitamin E and fatty acids in the major lipid classes-triacylglycerol, phospholipids, cholesteryl ester, free fatty acids), nitrogen (an index of protein) were measured during the different developmental stages throughout gestation, and in neonates. A significant net uptake of inorganic and organic matter was found. This uptake begins slowly during early gestation but accelerates during the last third of gestation when the growth of the embryo is maximal and the allantoplacenta has developed its greatest complexity. The drastic reduction of egg size in this clade is related to the great reduction in the contribution of lecithotrophic nutrients to the embryo, an obligatory placentotrophy from early developmental stages, and the highest placental complexity known in the Reptilia. All of these features converge with features found in eutherian mammals.

  10. Receiver functions and crustal structure of the northwestern Andean region, Colombia (United States)

    Poveda, Esteban; Monsalve, Gaspar; Vargas, Carlos Alberto


    We used the receiver function technique to deduce crustal thickness beneath the northwestern Andean system, using data from the permanent seismic network of Colombia, combined with some of the IRIS and CTBTO stations in Colombia and Ecuador. The estimation of crustal thickness was made using the primary P to s conversion and crustal reverberations. The bulk crustal VP/VS ratio was constrained using a crustal thickness versus VP/VS stacking method, in addition to estimations using a time to depth conversion technique based on results of a modified Wadati diagram analysis. We observed a wide range of crustal thicknesses, including values around 17 km beneath the Malpelo Island on the Pacific Ocean, 20 to 30 km at the coastal Pacific and Caribbean plains of Colombia, 25 to 40 km beneath the eastern plains and foothills, 35 km beneath the Western Cordillera, 45 km at the Magdalena River intermountain valley, 52 to 58 km under the northern Central Cordillera, and reaching almost 60 km beneath some of the volcanoes of the Southern Cordilleran system of Colombia; crustal thickness can be slightly greater than 60 km beneath the plateau of the Eastern Cordillera. The values of VP/VS are particularly high for some of the stations on the volcanic centers, reaching values above 1.79, probably related to the addition of mafic materials to the lower crust, and in the plateau of the Eastern Cordillera near Bogota, where we speculate about the possibility of crustal seismic anisotropy associated with shear zones.

  11. [Floristic composition and distribution of the Andean subtropical riparian forests of Lules River, Tucuman, Argentina]. (United States)

    Sirombra, Martín G; Mesa, Leticia M


    We studied the floristic composition and distribution of the riparian forest of two hydrographical systems in a subtropical Andean region. Using uni and multivariate techniques, we tested the hypotheses that a differentiable riparian forest exists, composed by native vegetation typical of the Yungas phytogeographical province, and that the distribution of vegetation varied significantly with geomorphologic characteristics. Parallel transects along the water courses were used to collect presence-absence data of vegetation in eleven sites. Detrended Correspondence Analysis defined a group of common riparian species for the studied area (Solanum riparium, Phenax laevigatus, Tipuana tipu, Cestrum parqui, Carica quercifolia, Acacia macracantha, Celtis iguanaea, Juglans australis, Pisoniella arborescens, Baccharis salicifolia, Cinnamomum porphyrium and Eugenia uniflora) and identified two reference sites. The distribution of the riparian vegetation varied significantly with the geomorphic characteristics along the studied sites. Riparian habitats were composed by native and exotic species. A distinct riparian flora, different in structure and function from adjacent terrestrial vegetation, could not be identified. Riparian species were similar to the adjacent terrestrial strata. These species would not be limited by the proximity to the river. Anthropogenic impacts were important factors regulating the introduction and increase of exotic vegetation. The lack of regulation of some activities in the zone could cause serious problems in the integrity of this ecosystem.

  12. Probabilistic estimation of glacier volume and glacier bed topography: the Andean glacier Huayna West

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    V. Moya Quiroga


    Full Text Available Glacier retreat will increase sea level and decrease fresh water availability. Glacier retreat will also induce morphologic and hydrologic changes due to the formation of glacial lakes. Hence, it is important not only to estimate glacier volume, but also to understand the spatial distribution of ice thickness. There are several approaches for estimating glacier volume and glacier thickness. However, it is not possible to select an optimal approach that works for all locations. It is important to analyse the relation between the different glacier volume estimations and to provide confidence intervals of a given solution. The present study presents a probabilistic approach for estimating glacier volume and its confidence interval. Glacier volume of the Andean glacier Huayna West was estimated according to different scaling relations. Besides, glacier volume and glacier thickness were estimated assuming plastic behaviour. The present study also analysed the influence of considering a variable glacier density due to ice firn densification. It was found that the different estimations are described by a lognormal probability distribution. Considering a confidence level of 90%, the estimated glacier volume is 0.0275 km3 ± 0.0052 km3. Considering a confidence level of 90%, the estimated glacier thickness is 24.98 m with a confidence of ±4.67 m. The mean basal shear stress considering plastic behaviour is 82.5 kPa. The reconstruction of glacier bed topography showed the future formation of a glacier lake with a maximum depth of 32 m.

  13. Gut Microbiome of an 11th Century A.D. Pre-Columbian Andean Mummy.

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    Tasha M Santiago-Rodriguez

    Full Text Available The process of natural mummification is a rare and unique process from which little is known about the resulting microbial community structure. In the present study, we characterized the microbiome of paleofeces, and ascending, transverse and descending colon of an 11th century A.D. pre-Columbian Andean mummy by 16S rRNA gene high-throughput sequencing and metagenomics. Firmicutes were the most abundant bacterial group, with Clostridium spp. comprising up to 96.2% of the mummified gut, while Turicibacter spp. represented 89.2% of the bacteria identified in the paleofeces. Microbiome profile of the paleofeces was unique when compared to previously characterized coprolites that did not undergo natural mummification. We identified DNA sequences homologous to Clostridium botulinum, Trypanosoma cruzi and human papillomaviruses (HPVs. Unexpectedly, putative antibiotic-resistance genes including beta-lactamases, penicillin-binding proteins, resistance to fosfomycin, chloramphenicol, aminoglycosides, macrolides, sulfa, quinolones, tetracycline and vancomycin, and multi-drug transporters, were also identified. The presence of putative antibiotic-resistance genes suggests that resistance may not necessarily be associated with a selective pressure of antibiotics or contact with European cultures. Identification of pathogens and antibiotic-resistance genes in ancient human specimens will aid in the understanding of the evolution of pathogens as a way to treat and prevent diseases caused by bacteria, microbial eukaryotes and viruses.

  14. Vicuña conservation and poverty alleviation? Andean communities and international fibre markets

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    Gabriela Lichtenstein


    Full Text Available Vicuna (Vicugna vicugna fiber is produced by extremely low-income communities that inhabit the harsh environment of the Andes in Argentina, Chile, Peru and Bolivia. At the other end of the social scale, affluent consumers are willing to pay high prices for vicuna-made accessories and clothes. Vicuna management projects follow the logic of community-based wildlife management. The rationale for seeking to conserve vicuñas through sustainable use is that commercial utilization of the fiber (obtained from live-shorn animals will generate sufficient economic benefits to outweigh the costs of conservation, and contribute to community development and poverty alleviation. However, although conservation efforts have been extremely successful with vicuñas having recovered from the brink of extinction, the socio-economic achievements have thus far proved modest. This paper explores multiple-objective projects that address vicuña conservation and poverty alleviation in Andean countries. In doing so it analyses the tensions that exist between these objectives, as well as the factors that limit a more equitable distribution of benefits among stakeholders. Examples are drawn from vicuna management under common-property in Peru and Bolivia, and vicuna captive management under private property in Argentina. These case studies enable us to illustrate the complex relationship between local communities and the global market, and the importance of community enterprises and supportive government policy in managing a common pool resource.

  15. Revisiting the Andean butterfly Eryphanis zolvizora group (Lepidoptera, Nymphalidae: one or several species?

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    Patrick Blandin


    Full Text Available Eryphanis zolvizora (Hewitson, 1877 is a rare Andean endemic butterfly, described from Bolivia, which has been historically classified either as a unique species, or as part of a group of three allopatric species from Bolivia, Ecuador and Colombia. In this paper, the group is revised using more than 200 specimens housed in 34 European, and North and South American public and private collections. For the first time, the presence of the group in Western Ecuador and Venezuela is confirmed, and important data on Peruvian populations are provided. In some populations, individual variations of genitalia are observed. Nevertheless, male genitalia allow the distinction of four geographical groups. Considering also habitus characters, eight taxa are distinguished and considered to be subspecies, of which five are new: Eryphanis zolvizora inca ssp. nov., Eryphanis zolvizora chachapoya ssp. nov., Eryphanis zolvizora casagrande ssp. nov.., Eryphanis zolvizora reyi ssp. nov., and Eryphanis zolvizora isabelae ssp. nov.  In the present state of knowledge, these taxa are allopatric, except for a possible geographic overlap in central Peru, where data are insufficient to prove sympatry. The “several subspecies vs. several species” dilemma is discussed, considering its impact for conservation action and policies.

  16. Large-Scale Patterns of Turnover and Basal Area Change in Andean Forests (United States)

    Blundo, Cecilia; Aguilar, Manuel; Aguirre, Nikolay; Aquirre, Zhofre; Álvarez, Esteban; Cuesta, Francisco; Farfán-Ríos, William; García-Cabrera, Karina; Grau, Ricardo; Linares-Palomino, Reynaldo; Malizia, Lucio R.; Cruz, Omar Melo; Osinaga, Oriana; Reynel, Carlos; Silman, Miles R.


    General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment) and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century. PMID:25973977

  17. Diversification of the rainfrog Pristimantis ornatissimus in the lowlands and Andean foothills of Ecuador. (United States)

    Guayasamin, Juan M; Hutter, Carl R; Tapia, Elicio E; Culebras, Jaime; Peñafiel, Nicolás; Pyron, R Alexander; Morochz, Carlos; Funk, W Chris; Arteaga, Alejandro


    Geographic barriers and elevational gradients have long been recognized as important in species diversification. Here, we illustrate an example where both mechanisms have shaped the genetic structure of the Neotropical rainfrog, Pristimantis ornatissimus, which has also resulted in speciation. This species was thought to be a single evolutionary lineage distributed throughout the Ecuadorian Chocó and the adjacent foothills of the Andes. Based on recent sampling of P. ornatissimus sensu lato, we provide molecular and morphological evidence that support the validity of a new species, which we name Pristimantis ecuadorensis sp. nov. The sister species are elevational replacements of each other; the distribution of Pristimantis ornatissimus sensu stricto is limited to the Ecuadorian Chocó ecoregion (< 1100 m), whereas the new species has only been found at Andean localities between 1450-1480 m. Given the results of the Multiple Matrix Regression with Randomization analysis, the genetic difference between P. ecuadorensis and P. ornatissimus is not explained by geographic distance nor environment, although environmental variables at a finer scale need to be tested. Therefore this speciation event might be the byproduct of stochastic historic extinction of connected populations or biogeographic events caused by barriers to dispersal such as rivers. Within P. ornatissimus sensu stricto, morphological patterns and genetic structure seem to be related to geographic isolation (e.g., rivers). Finally, we provide an updated phylogeny for the genus, including the new species, as well as other Ecuadorian Pristimantis.

  18. Two new Liolaemus lizards from the Andean highlands of Southern Chile (Squamata, Iguania, Liolaemidae) (United States)

    Troncoso-Palacios, Jaime; Diaz, Hugo A.; Puas, German I.; Riveros-Riffo, Edvin; Elorza, Alvaro A.


    Abstract Liolaemus is a diverse genus of lizards, subdivided into two subgenera: Liolaemus (sensu stricto) and Eulaemus, distributed mainly in Chile and Argentina. The Liolaemus elongatus-kriegi complex is the most diverse group within Liolaemus (sensu stricto), especially the species closely related to Liolaemus elongatus, which form a clade currently comprising nine species. Several Chilean species of this group have been recently described, mainly from volcanoes and poorly explored mountains. Here molecular and morphological evidence are provided for a new species of the Liolaemus elongatus clade, which is characterized by its small size and lack of dorsal pattern, unusual features for the species of this group of lizards. Additionally, the lack of precloacal pores in males of Liolaemus (sensu stricto) is a trait found in few species, which do not constitute a monophyletic group. A second new southern Chilean species is also described, without precloacal pores and supported by molecular phylogenetics to be related to Liolaemus villaricensis. Both new species were found in the same locality, near a lake located in a pre-Andean zone with Araucaria and Nothofagus forest. The two species are dedicated to prominent Lonkos (tribal chiefs) of the Mapuche and Pehuenche people: Janequeo and Leftraru. Additionally, the phylogenetic results suggest that Liolaemus lonquimayensis is a synonym of Liolaemus elongatus. PMID:27920609

  19. First insights on the molybdenum-copper Bled M'Dena complex (Eglab massif, Algeria) (United States)

    Lagraa, Karima; Salvi, Stefano; Béziat, Didier; Debat, Pierre; Kolli, Omar


    Molybdenum-Copper showings in the Eglab massif (eastern part of the Reguibat rise of Algeria), are found in quartz-monzodiorite and granodiorite of the Bled M'Dena complex, a Paleoproterozoic circular structure of ∼5 km in diameter, comprising volcanic and intrusive suites. The latter consist of quartz-diorite, quartz-monzodiorite and granodiorite with a metaluminous normative composition. They display an "adakitic character" with moderate light rare-earth element (LREE) enrichment, minor Eu anomalies, high Sr/Y ratio and low Yb concentration, suggestive of a hydrous, arc magma of volcanic-arc affinity. The mineralization occurs mostly in quartz + molybdenite + chalcopyrite stockwork veins marked by widespread propylitic alteration along the selvages. Molybdenite and chalcopyrite are commonly associated with calcite, which precipitated at relatively late stages of the hydrothermal alteration. Fluid inclusions related to the mineralization stage, range from aqueous to aqueous-carbonic to solid bearing. The latter inclusions have the highest homogenization temperature (up to ∼400 °C), are salt saturated, and commonly contain molybdenite and/or chalcopyrite crystals. The petrology and geochemistry of the host rocks, the style of the hydrothermal alteration, the ore mineral associations, and the characteristics of the fluid inclusions, are all coherent in indicating that the Bled M'Dena represents a Paleoproterozoic porphyry style Mo mineralization, which is far unreported in the African continent.

  20. Direct Production of Copper (United States)

    Victorovich, G. S.; Bell, M. C.; Diaz, C. M.; Bell, J. A. E.


    The use of commercially pure oxygen in flash smelting a typical chalcopyrite concentrate or a low grade comminuted matte directly to copper produces a large excess of heat. The heat balance is controlled by adjusting the calorific value of the solid feed. A portion of the sulfide material is roasted to produce a calcine which is blended with unroasted material, and the blend is then autogeneously smelted with oxygen and flux directly to copper. Either iron silicate or iron calcareous slags are produced, both being subject to a slag cleaning treatment. Practically all of the sulfur is contained in a continuous stream of SO2 gas, most of which is strong enough for liquefaction. A particularly attractive feature of these technologies is that no radically new metallurgical equipment needs to be developed. The oxygen smelting can be carried out not only in the Inco type flash furnace but in other suitable smelters such as cyclone furnaces. Another major advantage stems from abolishion of the ever-troublesome converter aisle, which is replaced with continuous roasting of a fraction of the copper sulfide feed.

  1. Oxidation Mechanism of Copper Selenide (United States)

    Taskinen, Pekka; Patana, Sonja; Kobylin, Petri; Latostenmaa, Petri


    The oxidation mechanism of copper selenide was investigated at deselenization temperatures of copper refining anode slimes. The isothermal roasting of synthetic, massive copper selenide in flowing oxygen and oxygen - 20% sulfur dioxide mixtures at 450-550 °C indicate that in both atmospheres the mass of Cu2Se increases as a function of time, due to formation of copper selenite as an intermediate product. Copper selenide oxidises to copper oxides without formation of thick copper selenite scales, and a significant fraction of selenium is vaporized as SeO2(g). The oxidation product scales on Cu2Se are porous which allows transport of atmospheric oxygen to the reaction zone and selenium dioxide vapor to the surrounding gas. Predominance area diagrams of the copper-selenium system, constructed for selenium roasting conditions, indicate that the stable phase of copper in a selenium roaster gas with SO2 is the sulfate CuSO4. The cuprous oxide formed in decomposition of Cu2Se is further sulfated to CuSO4.

  2. Copper and copper-nickel-alloys - An overview

    Energy Technology Data Exchange (ETDEWEB)

    Klassert, Anton; Tikana, Ladji [Deutsches Kupferinstitut e.V. Am Bonneshof 5, 40474 Duesseldorf (Germany)


    With the increasing level of industrialization the demand for and the number of copper alloys rose in an uninterrupted way. Today, the copper alloys take an important position amongst metallic materials due to the large variety of their technological properties and applications. Nowadays there exist over 3.000 standardized alloys. Copper takes the third place of all metals with a worldwide consumption of over 15 millions tons per year, following only to steel and aluminum. In a modern industrial society we meet copper in all ranges of the life (electro-technology, building and construction industry, mechanical engineering, automotive, chemistry, offshore, marine engineering, medical applications and others.). Copper is the first metal customized by humanity. Its name is attributed to the island Cyprus, which supplied in the antiquity copper to Greece, Rome and the other Mediterranean countries. The Romans called it 'ore from Cyprus' (aes cyprium), later cuprum. Copper deposited occasionally also dapper and could be processed in the recent stone age simply by hammering. Already in early historical time copper alloys with 20 to 50 percent tin was used for the production of mirrors because of their high reflecting power. Although the elementary nickel is an element discovered only recently from a historical perspective, its application in alloys - without any knowledge of the alloy composition - occurred at least throughout the last 2.000 years. The oldest copper-nickel coin originates from the time around 235 B.C.. Only around 1800 AD nickel was isolated as a metallic element. In particular in the sea and offshore technology copper nickel alloys found a broad field of applications in piping systems and for valves and armatures. The excellent combination of characteristics like corrosion resistance, erosion stability and bio-fouling resistance with excellent mechanical strength are at the basis of this success. An experience of many decades supports the use

  3. Mechanochemical reactions on copper-based compounds

    NARCIS (Netherlands)

    Castricum, H.L.; Bakker, H.; Poels, E.K.


    Mechanochemical reactions of copper and copper oxides with oxygen and carbon dioxide are discussed, as well as decomposition and reduction of copper compounds by mechanical milling under high-vacuum conditions.

  4. U/Pb ages on detrital zircons in the southern central Andes Neogene foreland (36°-37°S): Constraints on Andean exhumation (United States)

    Sagripanti, Lucía; Bottesi, Germán; Naipauer, Maximiliano; Folguera, Andrés; Ramos, Victor A.


    U/Pb dating on detrital zircons was performed in the Pampa de Carrizalito depocenter of the Late Miocene foreland basin associated with the Southern Central Andes orogenic front. This reveals Andean and pre-Andean components in magmatic derived zircons inhomogeneously distributed through the sequence. Andean, Grenville, Pampean, Famatinian and Gondwanic components reveal a complex source distribution from either the Main Andes, Coastal Cordillera and basement foreland areas. These are discussed showing different patterns in the context of the Andean orogenic cycle. Cretaceous and Jurassic components that are partly related to Mesozoic batholiths, developed at the western slope of the Andes at these latitudes, have a very contrasting behavior through the sequence: While Jurassic grains are represented from base to top, Cretaceous ones dilute upwardly. This is explained through the progressive uplift of the Southern Central Andes that could have created a barrier to Cretaceous and Jurassic detritus, while the older ones could have had either an alternative source area represented by the inverted rift system of the Huincul Ridge in the foreland area and the Cordillera del Viento in the hinterland area or the reworking of Jurassic sedimentary sequences of the Neuquén basin. Finally, a progressive enrichment in pre-Andean components to the top of the sequence is interpreted as related to the development of a broken foreland and the consequent rapid expansion of the orogenic front at the time of development of a slab shallowing setting in the region as shown by previous works.

  5. Removal of copper from ferrous scrap (United States)

    Blander, Milton; Sinha, Shome N.


    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  6. Nickel, copper and cobalt coalescence in copper cliff converter slag

    Directory of Open Access Journals (Sweden)

    Wolf A.


    Full Text Available The aim of this investigation is to assess the effect of various additives on coalescence of nickel, copper and cobalt from slags generated during nickel extraction. The analyzed fluxes were silica and lime while examined reductants were pig iron, ferrosilicon and copper-silicon compound. Slag was settled at the different holding temperatures for various times in conditions that simulated the industrial environment. The newly formed matte and slag were characterized by their chemical composition and morphology. Silica flux generated higher partition coefficients for nickel and copper than the addition of lime. Additives used as reducing agents had higher valuable metal recovery rates and corresponding partition coefficients than fluxes. Microstructural studies showed that slag formed after adding reductants consisted of primarily fayalite, with some minute traces of magnetite as the secondary phase. Addition of 5 wt% of pig iron, ferrosilicon and copper-silicon alloys favored the formation of a metallized matte which increased Cu, Ni and Co recoveries. Addition of copper-silicon alloys with low silicon content was efficient in copper recovery but coalescence of the other metals was low. Slag treated with the ferrosilicon facilitated the highest cobalt recovery while copper-silicon alloys with silicon content above 10 wt% resulted in high coalescence of nickel and copper, 87 % and 72 % respectively.

  7. Study of Copper Substitute in High Copper Price Market Environment

    Institute of Scientific and Technical Information of China (English)


    <正>The high price of copper drives up industry cost,also it is difficult for terminal products to raise price to transfer the cost pressure brought by increase in copper price,as a result downstream consumption markets instead try to seek

  8. Fixation Property of Copper Triazole Wood Preservatives

    Institute of Scientific and Technical Information of China (English)


    According to AWPA E11-2006 standard,copper fixation rates of several copper-based formulations,such as ammoniacal copper,amine copper,and ammoniacal-ethanolamine copper,as well as alkaline copper quaternary(ACQ),were tested and compared in this paper.And the fixation rates of tebuconazole(TEB) and propiconazole(PPZ) in several formulations,such as copper azole,emulsified type and solvent type,were also compared.The determination of copper content in the leachate was analyzed by atomic absorption spectrom...

  9. 东秦岭尚古寺斑岩钼矿地质特征及成矿潜力分析%Geological Characteristics and Prospecting Potential of the Shanggusi Porphyry Molybdenum Deposit in the East Qinling

    Institute of Scientific and Technical Information of China (English)

    杨宗锋; 罗照华; 卢欣祥; 黄凡; 陈必河


    尚古寺斑岩钼矿位于东秦岭,为东秦岭地区已知钼矿区的最东部端元。出露面积约1.5km^2,围岩主要为元古代片麻岩和碱流岩。辉钼矿化主要发育在花岗斑岩体的东部和南部区域,花岗斑岩顶部细粒花岗斑岩和其上覆花岗质伟晶岩均呈浸染状矿化,南部角岩发育裂隙矿化。花岗斑岩主体岩性主要矿物组合为石英、钾长石和斜长石,显示具有富硅、富碱和贫铁、贫镁的特征。花岗斑岩含有典型的圆粒状高温石英斑晶,其边部或整体呈现溶蚀吸回特征,溶蚀残余石英以港湾状、骨骸状和枝状为主,溶蚀部分被基质矿物充填或整体被钾长石和斜长石包裹,是高温花岗斑岩岩浆经历深部高温石英结晶后迅速就位浅部,发生快速不平衡结晶作用的产物。岩体内部发育中基性暗色微粒包体,呈球状、椭球状和塑性流动状态;富云母区域,呈不规则状和纹层状,暗示存在岩浆混合/混杂作用;蚀变晶洞构造、连通晶洞构造、空腔构造、硫化物蚀变突起和纵向蛇曲状云母富集区,记录了花岗斑岩内部流体出溶和运移的现象。花岗斑岩顶部过冷结晶形成的细粒花岗斑岩外壳,和其过冷前锋快速形成的花岗质伟晶岩圈闭了成矿流体,形成浸染状矿化。尚古寺斑岩钼矿是壳源岩浆和深部成矿流体耦合成矿的实例,对应于透岩浆流体成矿体系中的正岩浆成矿亚体系和边缘伟晶岩成矿亚体系,因而斑岩内部未出露部分可能依然具有巨大的成矿潜力。%The Shanggusi porphyry molybdenum deposit is located in the easternmost part of all the known molybdenum deposits in the East Qinling with an outcrop area about 1.5km^2. Disseminated molybdenite mineralization occurred in the marginal fine-grain porphyry granite and the periphery granitic pegmatite in the east and south part of the Shanggusi granite porphyry

  10. Characterization and zircon SHRIMP U-Pb geochronology of the subvolcanic rocks from Yarumalito Porphyry System, Marmato District, Colombia; Caracterizacao e geocronologia SHRIMP U-Pb em zircao das rochas subvulcanicas do sistema porfiro Yarumalito, Distrito de Marmato, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Henrichs, Isadora A.; Frantz, Jose Carlos; Marques, Juliana C.; Castoldi, Marco S., E-mail:, E-mail:, E-mail: [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Geociencias; Ordonez-Carmona, Oswaldo, E-mail: [Universidad Nacional de Colombia, Medellin (Colombia). Facultad de Minas; Sato, Kei, E-mail: [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Centro de Pesquisas Geocronologicas


    The mining District of Marmato, located in the Central Cordillera, is considered one of the oldest gold districts in Colombia and its exploration dates back to the Inca’s times, being exploited regularly for more than a thousand years. Inserted in this context lies the Yarumalito porphyry system (YPS), characterized to concentrate ore in structure related veins and stockworks. The YPS is related to the Miocene magmatism of the Combia Formation. In this paper, the subvolcanic rocks directly associated with the mineralized zones were described in order to obtain U-Pb ages in zircon to the intrusions. Selected samples from two fertile intrusions, one andesitic (more abundant in the area) and other dioritic (more restricted), were carefully described and dated by SHRIMP. The results points to a very restricted interval for the ages, with weighted average {sup 206}Pb/{sup 238}U varying from 7,00 ± 0,15 Ma for the andesitic porphyry and 6.95 ± 0.16 Ma for the dioritic porphyry. These results constrain the Yarumalito system to the final stages of the Combia magmatism and suggest a brief period for the crystallization of the mineralized subvolcanic rocks in the area and in the Marmato District. (author)

  11. Synthesis of copper/copper oxide nanoparticles by solution plasma (United States)

    Saito, Genki; Hosokai, Sou; Tsubota, Masakatsu; Akiyama, Tomohiro


    This paper describes the synthesis of copper/copper oxide nanoparticles via a solution plasma, in which the effect of the electrolyte and electrolysis time on the morphology of the products was mainly examined. In the experiments, a copper wire as a cathode was immersed in an electrolysis solution of a K2CO3 with the concentration from 0.001 to 0.50 M or a citrate buffer (pH = 4.8), and was melted by the local-concentration of current. The results demonstrated that by using the K2CO3 solution, we obtained CuO nanoflowers with many sharp nanorods, the size of which decreased with decreasing the concentration of the solution. Spherical particles of copper with/without pores formed when the citrate buffer was used. The pores in the copper nanoparticles appeared when the applied voltage changed from 105 V to 130 V, due to the dissolution of Cu2O.

  12. Electroleaching of Copper Waste with Recovery of Copper by Electrodialysis

    Directory of Open Access Journals (Sweden)

    Nuñez P.


    Full Text Available A new process to leach and recover copper from solid waste using electric fields was designed. The leaching with electro migration is presented as an alternative to traditional leaching. Preliminary data indicate that the copper ion migration is facilitated by using the electrical potential difference; therefore applying a potential difference in the processes of leaching facilitates the removal of copper. This is especially useful when mineral concentrations are very low. Different phenomena associated with transport of copper in solution are studied to generate a model able predict the state of the copper ion concentration in time. A kinetic model for the process was developed and fitted very well the experimental data.

  13. Fault Control on Copper Depositsin the Sar Cheshmeh Area Indicated by Remote Sensing & Geographic Information Systems (GIS

    Directory of Open Access Journals (Sweden)

    Hojjat Ollah Safari


    Full Text Available Introduction The Sar Cheshmeh copper deposit and indications of other deposits are located in the Dehaj-Sarduieh belt in the Kerman region (Khadem and Nedimovic, 1973. This belt is one of the most important provinces of Cu mineralization in Iran, with approximately 300 Cu deposits and prospects, includingtwenty of the porphyry copper type (Ghorbani, 2013. This belt, 300 km in length and 30–45 km width, is situated in the southern part of the Uramia-Dokhtar volcanic belt in central Iran (Shafiei, 2010. Zarasvandi (2004 has proposed that faulting has played a role in the location of copper deposition in this area. Methods of Investigation In order to check Zarasvandi’s hypothesis, the spatial relationship between faults and Cu deposits was investigated using remote sensing and GIS techniques together with field investigations in the Sar Cheshmeh area. The the following steps were used in this research: 1. Review of available data 2. Surface geology field studies 3. Preparation of digital overlay of Copper occurrences 4. Analysis of the relationshipof faulting to Copper occurrences Using remote sensing techniques, a geometrically corrected satellite image was filtered with high pass and Sharpen Edge filters to detect possible lineaments (Lillesand and Keifer, 2008; Sabins, 1996. Directional filters (45º, 90º, 135º and 180º were then applied to the processed image to enhance the linear structures. Subsequently,the major lineaments were documented in the field as major and minor faults (Safari et al., 2011. Four main faults, designated as the Rafsanjan, Mani, Gaud-e-Ahmar and Sar Cheshmeh faultswere determined to be major. These faults were digitized and overlaid on other data layers in GIS environment. The strikes, dips, striae and directions of movementof the faultswere measured at 20 locations in the field. Structural analyses were done with Rose diagrams, calculation of P-axes and preparation of a structural map. Copper occurrences on the

  14. The Red de Monitoreo de BosquesAndinos: A communication platform for science and policy in the Andean countries (United States)

    Baez, S.; Cuesta, F. X.; Malizia, A.; Carilla, J.; Bustamante, M.; Yepes, A.


    A workshop held in October 2012 in Lima, Peru, brought together more than 40 scientists and policy makers working in Andean forest ecosystems, one of the richer and most threatened ecosystems of the world. Among the various results of the workshop, there is the formation of the network "Red de Bosques Andinos". The goals of the network include to stimulate scientific research in Andean forest ecosystems by promoting collaboration among scientists, and to serve as a platform to facilitate applied research and communication between scientists and policy makers. Current members of the network include scientists of Argentina, Colombia, Ecuador, Germany, Peru, USA, and representatives of Ministries of Environment and the National Climate Change Adaptation Programs of Colombia, Bolivia, Ecuador, and Peru. The network has started to work in two critical documents for the region. The first one is an extended protocol to monitor diversity and carbon in Andean forests. This protocol, partly based on unpublished efforts, has been developed by the Instituto de Ecología Regional, Universidad de Tucuman, Argentina, and has been revised and improved by experts working in the Andes. The document describe methods to document ecological changes that take place over mid- and long periods of time. It focuses on monitoring changes on the diversity and growth of trees, shrubs and lianas, cover of herbaceous species, and carbon content in forests. This extended protocol will be a useful tool for students and researchers interested in conducting long-term ecological research. Moreover, the use of this tool will produce standardized data needed to understand ecological processes that take place at large spatial scales. The document will be freely available at The second document consists of an analysis of the dynamics of trees and carbon in the Andean region. The members of the network have contributed with data of more than 70 permanent forest plots located from

  15. Studies of copper transport in mammalian cells using copper radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M. [University of Melbourne, Parkville, VIC (Australia). Department of Genetics; Smith, S. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Radiopharmaceuticals Division; Mercer, J. [Deakin University, Clayton, VIC (Australia). Centre of Cellular and Molecular Biology


    The trace element copper poses a major problem for all organisms. It is essential as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Using the copper radioisotopes {sup 64}Cu (t1/2 = 12.8 hr) and {sup 67}Cu (t1/2 = 61 hr) we have developed a number of systems for studying copper transport in mammalian cells. These include investigation of copper uptake, copper efflux and ligand blot assays for Cu-binding proteins. Our studies have focused on Menkes disease which is an inherited and usually lethal copper deficiency disorder in humans. We have demonstrated that the Menkes protein is directly involved as a copper efflux pump in mammalian cells. Using cells overexpressing the Menkes protein we have provided the first biochemical evidence that this functions as a Cu translocating (across the membrane) P-type ATPase (Voskoboinik et al., FEBS Letters, in press). These studies were carried out using purified plasma membrane vesicles. We are now carrying out structure- function studies on this protein using targeted mutations and assaying using the radiocopper vesicle assay. Recently we have commenced studies on the role of amyloid precursor protein (APP) in copper transport and relationship of this to Alzheimers disease

  16. Assessment of terrain slope influence in SWAT modeling of Andean watersheds (United States)

    Yacoub, C.; Pérez-Foguet, A.


    Hydrological processes in the Andean Region are difficult to model. Large range of altitudes involved (from over 4000 meters above sea level, masl, to zero) indicates the high variability of rainfall, temperature and other climate variables. Strong runoff and extreme events as landslides and floods are the consequence of high slopes of terrain, especially in the upper part of the basins. Strong seasonality of rain and complex ecosystems (vulnerable to climate changes and anthropogenic activities) helps these processes. Present study focuses in a particular watershed from Peruvian Andes, the Jequetepeque River. The distributed watershed simulation model, Soil and Water Assessment Tool (SWAT) is applied to model run-off and sediments transport through the basin with data from 1997 to 2006. Specifically, the study focuses in the assessment of the influence of considering terrain slope variation in the definition of Hydrographical Response Units within SWAT. The Jequetepeque watershed (4 372.5 km2) is located in the north part of Peru. River flows east to west, to the Pacific Ocean. Annual average precipitation ranges from 0 to 1100 mm and altitude from 0 to 4188 masl. The "Gallito Ciego" reservoir (400 masl) separates upper-middle part from lower part of the watershed. It stores water for supplying the people from the big cities on the coast and for extensive agriculture uses. Upper-middle part of the watershed covers 3564.8 km2. It ranges from 400 to 4188 masl in no more that 80 km, with slopes up to 20%. Main activities are agricultural and livestock and mining and about 80% of the population are rural. Annual mean temperature drops from 25.4 °C at the reservoir to less than 4 °C in the upper part. Also the highest rainfall variability is found in the upper-middle part of the watershed. Erosion produced by extreme events like 1997/98 "el Niño" Phenomenon is silting the reservoir faster than expected. Moreover, anthropogenic activities like agriculture and

  17. Aerosol transport of biomass burning to the Bolivian Andean region from remote sensing measurements (United States)

    Perez-Ramirez, Daniel; Whiteman, David; Andrade, Marcos; Gasso, Santiago; Stein, Ariel; Torres, Omar; Eck, Tom; Velarde, Fernando; Aliaga, Diego


    This work deals with the analysis of columnar aerosol optical and microphysical properties obtained by the AERONET network in the region of Bolivia and its border with Brazil. Through the long record AERONET measurements we focus in the transport of biomass-burning aerosol from the Amazon basin (stations at Rio Branco, Cuiba, Ji Parana and Santa Cruz) to the Andean Altiplano (altitude above 3000 m a.s.l. at the station in the city of La Paz). Also, measurements from the space-sensors MODIS and OMI are used to understand spatial distribution. The main results is the high impact in the aerosol load during the months of August, September and August with mean values of aerosol optical depth at 500 nm (AOD) at the low lands of ≈ 0.60 ± 0.60 and Angstrom exponent (α(440-870)) of ≈ 1.52 ± 0.38. Satellite measurements also follow very similar patterns. Also, that season is characterized by some extreme events that can reach AOD of up to 6.0. Those events are cloud-screened by MODIS but not by OMI sensor, which is attributed to different pixel resolutions. The biomass-burning is clearly transport to the Andean region where higher values of AOD (~ 0.12 ± 0.06 versus 0.09 ± 0.04 in the no biomass-burning season) and α(440-870) (~ 0.95 ± 0.30 versus 0.84 ± 0.3 in the no biomass-burning season). However, the intensity of the biomass-burning season varies between different years. Analysis of precipitation anomalies using TRNM satellites indicates a strong correlation with AOD, which suggest that on dry years there is less vegetation to burn and so less aerosol load. The opposite is found for positive anomalies of precipitation. In the transport of biomass burning larger values of the effective radius (reff) are observed in La Paz (reff = 0.26 ± 0.10 μm) than in the low lands (reff = 0.63 ± 0.24 μm), which has been explained by aerosol aging processes. Moreover, although the spectral dependence is similar, single scattering albedo (SSA) is larger in the low lands

  18. Geometric, Kinematic, and Erosional history of the Central Andean Plateau, northern Bolivia (United States)

    McQuarrie, N.; Barnes, J. B.; Ehlers, T. A.


    Latitudinal changes in topography, climate, and thrust-belt geometry in the Central Andes have lead to conflicting hypotheses that climate or tectonics exert a first-order control on the orogens' evolution. Models of climate/tectonic interactions are limited by a lack of detailed observations for both the long-term deformation and erosion history of the Andean fold-thrust belt. We contribute to this problem by combining a sequentially restored, balanced cross section across the northern Bolivia portion of the thrust belt (15-16°S) with 10 new and 51 previously published mineral cooling ages, documenting the timing and magnitude of exhumation across the cross section. The cross section was balanced and restored using the sinuous bed method. The restored section was also sequentially forward modeled using stratigraphic and cooling age constraints. Results indicate the Eastern Cordillera (EC) records the highest magnitudes of shortening (123 km or 55%). The Interandean zone (IAZ) has shortened 48 km or 30%. In both the EC and IAZ individual thrust sheets are tightly folded and have minor offsets of 1-5 km. The fold-thrust belt of the SAZ has multiple levels of detachments allowing for thrust sheets with large 6-17 km of offset. Total shortening in the SAZ is 66 km or 40%. Total shortening for the entire fold-thrust belt in this region is 276 km (39%). New cooling ages support previously published ages that indicate rapid exhumation of the EC from ~40-25 Ma and distributed exhumation of the entire fold-thrust belt from ~15-0 Ma. Cooling ages in the EC and IAZ do not appear affected by individual thrusts. Integrating the sequential reconstructions with a compilation of mineral cooling ages and onlapping sedimentary basins provides a means of comparing independently derived exhumation estimates and determining long term shortening rates. Combined exhumation estimates suggest ~9 km of exhumation in the EC ~5-9 km in the IAZ and 3-4 km in the SAZ. Long term shortening

  19. A Plasmodium falciparum copper-binding membrane protein with copper transport motifs


    Choveaux David L; Przyborski Jude M; Goldring JP


    Abstract Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper st...

  20. Nanocrystalline copper based microcomposites


    J.P. Stobrawa; Z.M. Rdzawski; W. Głuchowski; J. Domagała-Dubiel


    Purpose: The aim of this work was to investigate microstructure, mechanical properties and deformation behavior of copper microcomposites: Cu- Y2O3, Cu- ZrO2 and Cu-WC produced by powder metallurgy techniques.Design/methodology/approach: Tests were made with Cu-Y2O3, Cu-ZrO2 and Cu-WC microcomposites containing up to 2% of a strengthening phase. The materials were fabricated by powder metallurgy techniques, including milling of powders, followed by their compacting and sintering. The main mec...

  1. Bioprospecting in potato fields in the Central Andean Highlands: screening of rhizobacteria for plant growth-promoting properties. (United States)

    Ghyselinck, Jonas; Velivelli, Siva L S; Heylen, Kim; O'Herlihy, Eileen; Franco, Javier; Rojas, Mercy; De Vos, Paul; Prestwich, Barbara Doyle


    The Central Andean Highlands are the center of origin of the potato plant (Solanum tuberosum). Ages of mutualism between potato plants and soil bacteria in this region support the hypothesis that Andean soils harbor interesting plant growth-promoting (PGP) bacteria. Therefore, the aim of this study was to isolate rhizobacteria from Andean ecosystems, and to identify those with PGP properties. A total of 585 bacterial isolates were obtained from eight potato fields in the Andes and they were screened for suppression of Phytophthora infestans and Rhizoctonia solani. Antagonistic mechanisms were determined and antagonistic isolates were further tested for phosphate solubilization, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, and production of NH3- and indole-3-acetic acid (IAA). PGP was studied in healthy and R. solani diseased plantlets under growth room conditions. Performance was compared to the commercial strain B. subtilis FZB24(®) WG. Isolates were dereplicated with matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), and identified with 16S rRNA gene sequencing and multi locus sequence analysis (MLSA). A total of 10% of the isolates were effective antagonists, of which many were able to solubilize phosphate, and produce IAA, ACC deaminase, NH3 and hydrogen cyanide (HCN). During growth room experiments, 23 antagonistic isolates were associated with plant growth-promotion and/or disease suppression. Ten isolates had a statistically significant impact on test parameters compared to the uninoculated control. Three isolates significantly promoted plant growth in healthy plantlets compared to the commercial strain, and seven isolates outperformed the commercial strain in in vitro R. solani diseased plantlets.

  2. Latitudinal variations (18°-23°S) in denudation rates of western Andean Syntaxis, Chile, South America. (United States)

    Starke, Jessica; Ehlers, Todd A.; Schaller, Mirjam


    Keywords: Cosmogenic nuclides, denudation rates, channel steepness, Chi, syntax, North Chile, South Peru Syntaxial regions of orogens (e.g. the western and eastern Himalayan Syntaxes, St. Elias Mountains Alaska) are regions where curved segments of subducting plates meet and the subducting plate is bent forms a rigid indentor. Previous studies of syntaxial regions in the Himalaya and Alaska document localized and rapid deformation and denudation due to vigorous fluvial or glacial erosional processes. In this study we investigate denudation around an arid end-member syntaxial orogen in South America to understand the interactions between climate and tectonic processes in localizing denudation. We present 35 new cosmogenic 10Be analyses of river sediments to quantify spatial variations in erosion along the Andean Coastal Cordillera and Western Cordillera. The sizes of the drainage basin vary from 5 - 5000 square kilometers. These measurements are linked to analysis of digital topography, variations in fluvial steepness indices and Chi- plots. Cosmogenic derived denudation rates range from 2.5 - 130 mm/kyr. Denudation rates decrease generally from the syntaxis (near Arica, Chile) towards the south (near Antofagasta, Chile) and from the Western Cordillera to the Coastal Cordillera. Topographic analysis of channel steepness variations and Chi-plots also document spatial variations in fluvial erosion and are consistent with spatial pattern in cosmogenic derived denudation rates. In summary the results document both a north to south and east to west variation in denudation around the western Andean margin. The spatial pattern of denudation is consistent with recently proposed patterns of syntaxial deformation driven by the geometry of the bent subducting plate. Denudation rates are also likely influenced to a lesser degree by a latitudinal variation in climate along the Andean margin.

  3. The Andean Biotic Index (ABI): revised tolerance to pollution values for macroinvertebrate families and index performance evaluation. (United States)

    Ríos-Touma, Blanca; Acosta, Raúl; Prat, Narcís


    Score-based biotic indices are widely used to evaluate the water quality of streams and rivers. Few adaptations of these indices have been done for South America because there is a lack of knowledge on macroinvertebrate taxonomy, distribution and tolerance to pollution in the region. Several areas in the Andes are densely populated and there is need for methods to assess the impact of increasing human pressures on aquatic ecosystems. Considering the unique ecological and geographical features of the Andes, macroinvertebrate indices used in other regions must be adapted with caution. Here we present a review of the literature on macroinvertebrate distribution and tolerance to pollution in Andean areas above 2,000 masl. Using these data, we propose an Andean Biotic Index (ABI), which is based on the BMWP index. In general, ABI includes fewer macroinvertebrate families than in other regions of the world where the BMWP index has been applied because altitude restricts the distribution of several families. Our review shows that in the high Andes, the tolerance of several macroinvertebrate families to pollution differs from those reported in other areas. We tested the ABI index in two basins in Ecuador and Peru, and compared it to other BMWP adaptations using the reference condition approach. The ABI index is extremely useful for detecting the general impairment of rivers but class quality boundaries should be defined independently for each basin because reference conditions may be different. The ABI is widely used in Ecuador and Peru, with high correlations with land-use pressures in several studies. The ABI index is an integral part of the new multimetric index designed for high Andean streams (IMEERA).

  4. Late Glacial-Holocene climatic transition record at the Argentinian Andean piedmont between 33–34° S

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    A. E. Mehl


    Full Text Available The Arroyo La Estacada (~33°28' S, 69°02' W, eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant late Pleistocene–early Holocene (LP–EH alluvial sequence including several paleosols. The arroyo sedimentary record exhibits a paleosol developed affecting the topmost part of likely Lateglacial aeolian deposits aggraded into a floodplain environment by the end of the late Pleistocene. The paleosol shows variable grade of development in the outcrops along the arroyo probably in relation to fluvial valley paleotopography. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, alluvial aggradation renewed and a higher frequency of flooding events could have affected the arroyo's floodplain environment. A period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP–EH transition in response to a climatic amelioration in the Andes cordillera piedmont after the Late Glacial arid conditions. The renewal of early Holocene alluvial aggradation was probably influenced by the South American Monsoon and resulted in a change in the sedimentary dynamics of the arroyo. The analyzed Late Glacial-Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP–EH climatic transition at the extra Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other sedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

  5. Along-Strike Variations in Focal Mechanisms of Central Andean Crustal Earthquakes: Northern Peru through the Argentina Sierras Pampeanas (United States)

    Devlin, S.; Isacks, B. L.


    120 shallow focal mechanisms in the crust above the subducted Nazca plate were assembled from the Harvard CMT catalog and published studies covering over 40 years of seismicity. The study area included the Andes crust above three major segments of the subducted plate, the Peruvian and Argentinean flat-slab segments and the intervening segment where the subducted Nazca plate dips more steeply. The most seismically active regions continue to be the thick-skinned foreland thrust belts in the eastern Andes of Peru and the Sierras Pampeanas. The earthquakes there are clearly associated with youthful tectonic structures with strong topographic signatures as revealed by the new 90 m SRTM digital elevation models. The mechanisms are dominantly of the thrust type but include a minority of strike-slip orientations. However the P axes remain consistent. The thin-skinned thrust belts east of the central Andean Plateau show significant activity only near Santa Cruz, Bolivia and northern Argentina; most of the Sub-Andean thrust belt of Bolivia and southern Peru remains aseismic. The central Andean plateau itself also remains aseismic except for the region of southern Peru and two earthquakes in the Puna. The crustal seismicity in southern Peru is largely concentrated on the western side of the plateau. The focal mechanisms show a strong grouping of T axes in a horizontal, north-south orientation. Both normal and strike-slip mechanisms occur in this region, with no obvious correlation with elevation or surface structures. Remarkably, with the exception of one normal fault type mechanism near the Cusco basin, the earthquakes occur in regions of the western parts of the Altiplano that do not exhibit topographic evidence of substantial crustal deformation. These results are consistent with a model in which the Altiplano of southern Peru, with a trend most oblique to the overall direction of convergence, manifests a left-lateral shearing component across the orogen.

  6. Realist evaluation of intersectoral oral health promotion interventions for schoolchildren living in rural Andean communities: a research protocol (United States)

    Talbot, Lise R; Gaboury, Isabelle


    Background Intersectoral collaboration, known to promote more sustainable change within communities, will be examined in an oral health promotion program (OHPP). In Peru, an OHPP was implemented by the Ministry of Health, to reduce the incidence of caries in schoolchildren. In rural Andean communities, however, these initiatives achieved limited success. The objectives of this project are: (1) to understand the context and the underlying mechanisms associated with Peruvian OHPP's current effects among school children living in rural Andean communities and (2) to validate a theory explaining how and under which circumstances OHP intersectoral interventions on schoolchildren living in rural Andean communities produce their effects. Methods and analysis Through a realist evaluation, the context, underlying mechanisms and programme outcomes will be identified. This process will involve five different steps. In the first and second steps, a logic model and an initial theory are developed. In the third step, data collection will permit measurement of the OHHP's outcomes with quantitative data, and exploration of the elements of context and the mechanisms with qualitative data. In the fourth and fifth steps, iterative data analysis and a validation process will allow the identification of Context-Mechanism-Outcome configuration, and validate or refine the initial theory. Ethics and dissemination This research project has received approval from the Comité d’éthique de la recherche en santé chez l'humain du Centre hospitalier universitaire de Sherbrooke. The initial theory and research results will be published in relevant journals in public health and oral health. They will also be presented at realist evaluation and health promotion international conferences. PMID:28237962

  7. The origin of oriented lakes in the Andean foreland, Parque Nacional Torres del Paine (Chilean Patagonia) (United States)

    Gonzales, Joseph; Aydin, Atilla


    The Parque Nacional Torres Del Paine and surrounding area in the Magallanes foreland basin in Chilean Patagonia is the site for numerous lakes fed by glaciers and rivers in the Andean highlands to the west. The lakes are elongate and have conspicuously systematic orientations. We hypothesize that the origin of the oriented lakes lies in the fault system, composed of a right-lateral strike-slip fault set oriented 58° from north, a left-lateral strike-slip set oriented 87°, and a thrust fault set oriented 167°, that exists within the underlying rocks. To test this hypothesis quantitatively, we determined the shape and orientation of the lakes by fitting each lake with an ellipse of appropriate aspect ratio, and later with multiple ellipses consistent with the composite geometry of some lakes. We then examined the faults in the area in terms of their kinematics, orientation and distribution. The distribution of lake orientations showed three distinct groups which appear to correspond to the three main fault groups. For lakes fitted with multiple ellipses, the difference in means between the right-lateral, left-lateral, and thrust faults and their corresponding groups of lakes are 3.05°, 1.57°, and 5.17°. Using a Kolmogorov-Smirnov (K-S) statistical test to compare the orientations of faults with respect to the lakes suggests that there is not a strongly significant difference between the fault orientations and the corresponding lake groups. These results indicate that the faults have a profound control on the orientation, shape, and distribution of the lakes. We attribute this to faults and their damage zones being weaker and therefore prone to a faster rate of erosion, and to stress perturbations associated with discontinuous faults resulting in localized high density fracturing and surface subsidence. These results have implications for lake and drainage system morphologies in other foreland basins along the Andes and other similar settings.

  8. Neurocognitive screening of mercury-exposed children of Andean gold miners. (United States)

    Counter, S Allen; Buchanan, Leo H; Ortega, Fernando


    Performance on Raven's Coloured Progressive Matrices (RCPM) test of visual-spatial reasoning was used to evaluate the effects of mercury (Hg) exposure on 73 Andean children aged 5 to 11 years (mean: 8.4) living in the Nambija and Portovelo gold mining areas of Ecuador, where Hg is widely used in amalgamation. Mean levels of Hg found in blood (Hg(B)), urine (Hg(U)), and hair (Hg(H)) samples were 5.1 microg/L (SD: 2.4; range: 1-10 microg/L), 13.3 microg/L (SD: 25.9; range: 1-166 microg/L), and 8.5 microg/g (SD: 22.8; range: 1-135 microg/g), respectively. Of the children in the Nambija area 67-84.9% had abnormal RCPM standard scores (i.e., < or = 25%tile), depending on the test norm used in the data analysis. Higher standard scores for Peruvian (t = 4.77; p = < 0.0001) and Puerto Rican (t = 4.51; p = < 0.0001) norms than for U.S. norms suggested a linguistic influence. No difference was found between Peruvian and Puerto Rican norms (t = 0.832; p = < 0.408), which showed a significant positive correlation (r = 0.915, p = < 0.0001). Children with abnormal Hg(B) and Hg(H) levels had significantly lower scores on the RCPM subtest B than did children with nontoxic Hg levels (t = -2.16; p = < 0.034). These results suggest that a substantial number of Hg-exposed children in the Nambija study area have neurocognitive deficits in visual-spatial reasoning.

  9. Low Herbivory among Targeted Reforestation Sites in the Andean Highlands of Southern Ecuador.

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    Marc-Oliver Adams

    Full Text Available Insect herbivory constitutes an important constraint in the viability and management of targeted reforestation sites. Focusing on young experimental stands at about 2000 m elevation in southern Ecuador, we examined foliar damage over one season as a function of tree species and habitat. Native tree species (Successional hardwood: Cedrela montana and Tabebuia chrysantha; fast-growing pioneer: Heliocarpus americanus have been planted among prevailing local landcover types (abandoned pasture, secondary shrub vegetation, and a Pinus patula plantation in 2003/4. Plantation trees were compared to conspecifics in the spontaneous undergrowth of adjacent undisturbed rainforest matched for height and foliar volume. Specifically, we tested the hypotheses that H. americanus as a pioneer species suffers more herbivory compared to the two successional tree species, and that damage is inversely related to habitat complexity. Overall leaf damage caused by folivorous insects (excluding leafcutter ants was low. Average leaf loss was highest among T. chrysantha (7.50% ± 0.19 SE of leaf area, followed by H. americanus (4.67% ± 0.18 SE and C. montana (3.18% ± 0.15 SE. Contrary to expectations, leaf area loss was highest among trees in closed-canopy natural rainforest, followed by pine plantation, pasture, and secondary shrub sites. Harvesting activity of leafcutter ants (Acromyrmex sp. was strongly biased towards T. chrysantha growing in open habitat (mean pasture: 2.5%; shrub: 10.5% where it could result in considerable damage (> 90.0%. Insect folivory is unlikely to pose a barrier for reforestation in the tropical Andean mountain forest zone at present, but leafcutter ants may become problematic if local temperatures increase in the wake of global warming.

  10. Low Herbivory among Targeted Reforestation Sites in the Andean Highlands of Southern Ecuador. (United States)

    Adams, Marc-Oliver; Fiedler, Konrad


    Insect herbivory constitutes an important constraint in the viability and management of targeted reforestation sites. Focusing on young experimental stands at about 2000 m elevation in southern Ecuador, we examined foliar damage over one season as a function of tree species and habitat. Native tree species (Successional hardwood: Cedrela montana and Tabebuia chrysantha; fast-growing pioneer: Heliocarpus americanus) have been planted among prevailing local landcover types (abandoned pasture, secondary shrub vegetation, and a Pinus patula plantation) in 2003/4. Plantation trees were compared to conspecifics in the spontaneous undergrowth of adjacent undisturbed rainforest matched for height and foliar volume. Specifically, we tested the hypotheses that H. americanus as a pioneer species suffers more herbivory compared to the two successional tree species, and that damage is inversely related to habitat complexity. Overall leaf damage caused by folivorous insects (excluding leafcutter ants) was low. Average leaf loss was highest among T. chrysantha (7.50% ± 0.19 SE of leaf area), followed by H. americanus (4.67% ± 0.18 SE) and C. montana (3.18% ± 0.15 SE). Contrary to expectations, leaf area loss was highest among trees in closed-canopy natural rainforest, followed by pine plantation, pasture, and secondary shrub sites. Harvesting activity of leafcutter ants (Acromyrmex sp.) was strongly biased towards T. chrysantha growing in open habitat (mean pasture: 2.5%; shrub: 10.5%) where it could result in considerable damage (> 90.0%). Insect folivory is unlikely to pose a barrier for reforestation in the tropical Andean mountain forest zone at present, but leafcutter ants may become problematic if local temperatures increase in the wake of global warming.

  11. High-up: a remote reservoir of microbial extremophiles at Central Andean Wetlands

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    Virginia Helena Albarracín


    Full Text Available The Central Andes region displays unexplored ecosystems of shallow lakes and salt flats at mean altitudes of 3,700 m. Being isolated and hostile, these so-called High-Altitude Andean Lakes (HAAL are pristine and have been exposed to little human influence. HAAL proved to be a rich source of microbes showing interesting adaptations to life in extreme settings (poly-extremophiles such as alkalinity, high concentrations of arsenic and dissolved salts, intense dryness, large daily ambient thermal amplitude, and extreme solar radiation levels. This work reviews HAAL microbiodiversity, taking into account different microbial niches, such as plankton, benthos, microbial mats and microbialites. The modern stromatolites and other microbialites discovered recently at HAAL are highlighted, as they provide unique modern -though quite imperfect- analogues of environments proxy for an earlier time in Earth’s history (volcanic setting and profuse hydrothermal activity, low atmospheric O2 pressure, thin ozone layer and high UV exposure. Likewise, we stress the importance of HAAL microbes as model poly-extremophiles in the study of the molecular mechanisms underlying their resistance ability against UV and toxic or deleterious chemicals using genome mining and functional genomics. In future research directions, it will be necessary to exploit the full potential of HAAL poly-extremophiles in terms of their biotechnological applications. Current projects heading this way have yielded detailed molecular information and functional proof on novel extremoenzymes: i.e. DNA repair enzymes and arsenic efflux pumps for which medical and bioremediation applications, respectively, are envisaged. But still, much effort is required to unravel novel functions for this and other molecules that dwell in a unique biological treasure despite its being hidden high up, in the remote Andes.

  12. High-Up: A Remote Reservoir of Microbial Extremophiles in Central Andean Wetlands. (United States)

    Albarracín, Virginia H; Kurth, Daniel; Ordoñez, Omar F; Belfiore, Carolina; Luccini, Eduardo; Salum, Graciela M; Piacentini, Ruben D; Farías, María E


    The Central Andes region displays unexplored ecosystems of shallow lakes and salt flats at mean altitudes of 3700 m. Being isolated and hostile, these so-called "High-Altitude Andean Lakes" (HAAL) are pristine and have been exposed to little human influence. HAAL proved to be a rich source of microbes showing interesting adaptations to life in extreme settings (poly-extremophiles) such as alkalinity, high concentrations of arsenic and dissolved salts, intense dryness, large daily ambient thermal amplitude, and extreme solar radiation levels. This work reviews HAAL microbiodiversity, taking into account different microbial niches, such as plankton, benthos, microbial mats and microbialites. The modern stromatolites and other microbialites discovered recently at HAAL are highlighted, as they provide unique modern-though quite imperfect-analogs of environments proxy for an earlier time in Earth's history (volcanic setting and profuse hydrothermal activity, low atmospheric O2 pressure, thin ozone layer and high UV exposure). Likewise, we stress the importance of HAAL microbes as model poly-extremophiles in the study of the molecular mechanisms underlying their resistance ability against UV and toxic or deleterious chemicals using genome mining and functional genomics. In future research directions, it will be necessary to exploit the full potential of HAAL poly-extremophiles in terms of their biotechnological applications. Current projects heading this way have yielded detailed molecular information and functional proof on novel extremoenzymes: i.e., DNA repair enzymes and arsenic efflux pumps for which medical and bioremediation applications, respectively, are envisaged. But still, much effort is required to unravel novel functions for this and other molecules that dwell in a unique biological treasure despite its being hidden high up, in the remote Andes.

  13. Monitoring the Diversity of Hunting Ants (Hymenoptera: Formicidae) on a Fragmented and Restored Andean Landscape. (United States)

    Herrera-Rangel, J; Jiménez-Carmona, E; Armbrecht, I


    Hunting ants are predators of organisms belonging to different trophic levels. Their presence, abundance, and diversity may reflect the diversity of other ants and contribute to evaluate habitat conditions. Between 2003 and 2005 the restoration of seven corridors in an Andean rural landscape of Colombia was performed. The restoration took place in lands that were formerly either forestry plantations or pasturelands. To evaluate restoration progress, hunting ants were intensely sampled for 7 yr, using sifted leaf litter and mini-Winkler, and pitfall traps in 21 plots classified into five vegetation types: forests, riparian forests, two types of restored corridors, and pasturelands. The ant communities were faithful to their habitat over time, and the main differences in ant composition, abundance, and richness were due to differences among land use types. The forests and riparian forests support 45% of the species in the landscape while the restored corridors contain between 8.3-25%. The change from forest to pasturelands represents a loss of 80% of the species. Ant composition in restored corridors was significantly different than in forests but restored corridors of soil of forestry plantations retained 16.7% more species than restored corridors from pasturelands. Ubiquitous hunting ants, Hypoponera opacior (Forel) and Gnamptogenys ca andina were usually associated with pastures and dominate restored corridors. Other cryptic, small, and specialized hunting ants are not present in the restored corridors. Results suggest that the history of land use is important for the biodiversity of hunting ants but also that corridors have not yet effectively contributed toward conservation goals.

  14. Ventilation, autonomic function, sleep and erythropoietin. Chronic mountain sickness of Andean natives. (United States)

    Bernardi, Luciano; Roach, Robert C; Keyl, Cornelius; Spicuzza, Lucia; Passino, Claudio; Bonfichi, Maurizio; Gamboa, Alfredo; Gamboa, Jorge; Malcovati, Luca; Schneider, Annette; Casiraghi, Nadia; Mori, Antonio; Leon-Velarde, Fabiola


    Polycythemia is one of the key factors involved in the chronic mountain sickness syndrome, a condition frequent in Andean natives but whose causes still remain unclear. In theory, polycythemia may be secondary to abnormalities in ventilation, occurring during day or night (e.g. due to sleep abnormalities) stimulating excessive erythropoietin (Epo) production, or else it may result from either autogenous production, or from co-factors like cobalt. To assess the importance of these points, we studied subjects with or without polycythemia, born and living in Cerro de Pasco (Peru, 4330m asl, CP) and evaluated the relationship between Epo and respiratory variables both in CP and sea level. We also assessed the relationship between sleep abnormalities and the circadian rhythm of Epo. Polycythemic subjects showed higher Epo in all conditions, lower SaO2 and hypoxic ventilatory response, higher physiological dead space and higher CO2, suggesting ventilatory inefficiency. Epo levels could be highly mo