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Sample records for cerro prieto hydrothermal

  1. Current state of the hydrothermal geochemistry studies at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Fausto L, J.J.; Jimenez S, M.E.; Esquer P, I.

    1981-01-01

    The current state of hydrothermal geochemistry studies being carried out at the field are reported. These studies are based on the results of chemical analysis of water samples collected during 1979 and 1980 at the geothermal wells of the area known as Cerro Prieto I, as well as from those located in the Cerro Prieto II and Cerro Prieto III areas, some of which have only recently started flowing. Data are presented on the chemical variations of the main chemical constituents dissolved in the waters, as well as on the Na/K and Na-K-Ca chemical relations and the temperatures calculated from them and from SiO/sub 2/. Fluid recharge into the reservoir and its direction of flow are interpreted from isotherm contour maps of the field prepared from Na/K and Na-K-Ca geothermometry and from concentration contour maps of some of the main chemical constituents. Well M-43 is discussed as an example of a well affected by well completion problems in its production casing. Its behavior is explained on the basis of the chemical characteristics of the produced water. The chemical changes that have taken place in some of the wells during production are explained by correlating the chemistry with the production mechanisms of the well (steam-water production rates).

  2. Hydrothermal alteration of sediments associated with surface emissions from the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N.; Esquer P., I.; Elders, W.A.; Collier, P.C.; Hoagland, J.R.

    1981-01-01

    A study of the mineralogical changes associated with these hydrothermal vents was initiated with the aim of developing possible exploration tools for geothermal resources. The Cerro Prieto reservoir has already been explored by extensive deep drilling so that relationships between surface manifestations and deeper hydrothermal processes could be established directly. Approximately 120 samples of surface sediments were collected both inside and outside of the vents. The mineralogy of the altered sediments studied appears to be controlled by the type of emission. A comparison between the changes in mineralogy due to low temperature hydrothermal activity in the reservoir, seen in samples from boreholes, and mineralogical changes in the surface emission samples shows similar general trends below 180 C: increase of quartz, feldspar and illite, with subsequent disappearance of kaolinite, montmorillonite, calcite and dolomite. These mineral assemblages seem to be characteristic products of the discharge from high intensity geothermal fields.

  3. Trace element and isotopic chemistry of the surficial hydrothermal waters in the Cerro Prieto, Geothermal Field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N.; Ganje, T.J.; Bradford, G.R.; Coplen, T.

    1982-08-10

    In the Cerro Prieto Geothermal Field, five kinds of surface emissions were discovered in spring, mud pot, geysers, fumarole, and cool pool. The major element composition of the 163 fluid samples collected in 1979, was previously performed. This study was recently completed by a determination of trace element concentrations, deuterium and oxygen isotope ratios. This geochemical analysis shows, as the major elements do, that each type of surficial emission is characterized by its own unique chemistry. Each category of surface emission appears to result from different processes; trace chemistry as well as isotope composition confirm the various origins of the different surface hydrothermal fluids.

  4. Geothermal drilling in Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez A., Bernardo

    1982-08-10

    The number of characteristics of the different wells that have been drilled in the Cerro Prieto geothermal field to date enable one to summarize the basic factors in the applied technology, draw some conclusions, improve systems and procedures, and define some problems that have not yet been satisfactorily solved, although the existing solution is the best now available. For all practical purposes, the 100 wells drilled in the three areas or blocks into which the Cerro Prieto field has been divided have been completed. Both exploratory and production wells have been drilled; problems of partial or total lack of control have made it necessary to abandon some of these wells, since they were unsafe to keep in production or even to be used for observation and/or study. The wells and their type, the type of constructed wells and the accumulative meters that have been drilled for such wells are summarized.

  5. Geohydrology of the Cerro Prieto geothermal aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez R, J.; de la Pena L, A.

    1981-01-01

    The most recent information on the Cerro Prieto geothermal aquifer is summarized, with special emphasis on the initial production zone where the wells completed in the Alpha aquifer are located. These wells produce steam for power plant units 1 and 2. Brief comments also are made on the Beta aquifer, which underlies the Alpha aquifer in the Cerro Prieto I area and which extends to the east to what is known as the Cerro Prieto II and Cerro Prieto III areas. The location of the area studied is shown. The Alpha and Beta aquifers differ in their mineralogy and cementing mineral composition, temperatures, and piezometric levels. The difference in piezometric levels indicates that there is no local communication between the two aquifers. This situation has been verified by a well interference test, using well E-1 as a producer in the Beta aquifer and well M-46 as the observation well in the Alpha aquifer. No interference between them was observed. Information on the geology, geohydrology, and geochemistry of Cerro Prieto is presented.

  6. An integrated model for the natural flow regime in the Cerro Prieto hydrothermal system based upon petrological and isotope geochemical criteria

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Williams, A.E.; Hoagland, J..

    1981-01-01

    Studies of cuttings and cores at Cerro Prieto have now been extended to more than 50 boreholes. The aims of this petrological and isotopic work are to determine the shape of the reservoir, its physical properties, and its temperature distribution and flow regime before the steam field was produced.

  7. Integrated model for the natural flow regime in the Cerro Prieto hydrothermal system, B. C. , Mexico, based upon petrological and isotope geochemical criteria

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Williams, A.E.; Hoagland, J.R.

    1981-01-01

    Studies of cuttings and core at Cerro Prieto have now been extended to more than 50 boreholes. The aims of this petrological and isotopic work are to determine the shape of the reservoir, its physical properties, and its temperature distribution and flow regime before the steam field was produced. A map showing the first occurrence of hydrothermal epidote shows a dome-shaped top to the steam-producing zone. The hottest of the mapped mineral zones - the biotite vermiculite zone - shows a dome displaced to the northeast relative to the epidote zone. Patterns of mineral zones observed in wells are consistent with patterns of oxygen isotopic ratios in calcite and quartz. Using both criteria all of the boreholes so far studied were classified as belonging to one of four different regimes. These are: (a) the thermal plume of upward flowing water close to boiling, marked by a regular sequence of prograde mineral zones and large isotopic shifts; (b) the discharge system where fluid leaks to the surface, as indicated by the occurrence of only a few low temperature mineral zones, which extend over large depth intervals with little isotope exchange; (c) the horizontal flow zone, in which boreholes penetrate reversals of both mineral zones and isotope shifts with increasing depth; and (d) the recharge zone where cold water is descending. Plotting these four types of boreholes on a map reveals a simple, consistent, pattern. This is interpreted to have been produced by a thermal plume dipping at 45/sup 0/ to the northeast.

  8. Evaluation of geologic characteristics at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.H.; Halfman, S.E.; Vonder Haar, S.P.

    1981-01-01

    Computerized well-log analysis of Cerro Prieto has led to the identification of a relatively large and irregular low-density volume extending from near the surface in the vicinity of Laguna Volcano to greater depths toward the northeast. This low-density volume is located about a plane of symmetry of a self-potential anomaly and a group of northeast trending active faults. The presence of a volume of relatively high-density rock has been recognized at shallow depths in the initially developed part of the resource. It is believed to be due to minerals deposited by cooled, rising geothermal brine. Storativity calculated from well logs at the south end of the western part of the field shows acceptable comparison with storativity calculated from well tests. The amount of fluid produced from the field during the period 1973-1977 is greater than the amount in situ calculated from the completed interval thicknesses. Because this part of the field is still producing today, fluid must be recharging this part of the field.

  9. Hydrothermal alteration zones and present reservoir conditions: an approach to define production zones at the eastern portion of the Cerro Prieto geothermal field, BC; Zonas de alteracion hidrotermal y condiciones actuales del yacimiento: un enfoque para determinar zonas productoras al oriente del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Camacho Hernandez, Juan Manuel [Comision Federal de Electricidad, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: juan.camacho02@cfe.gob.mx

    2009-07-15

    Geological factors are as essential for locating new wells as they are for defining the production zones of these wells. At the Cerro Prieto geothermal field (CGCP), one of the most important geological factors is identification of the hydrothermal alteration zones (ZAH). These are divided into silica and epidote mineralogical zones (ZMSE), without CaCO{sub 3}, and silica and epidote mineralogical transition zones (ZTMSE), with CaCO{sub 3}. It has been observed that the continuous variation of reservoir thermodynamic conditions (temperature, pressure and enthalpy) is due mainly to the exploitation of geothermal resources. The presence of new thermodynamic conditions recorded at the reservoir has led to the re-location of production wells originally located during the drilling campaign of 2004 to 2006. At the geological sections on the eastern part of the CGCP, adjustments made to the well completions lie on the limits between the ZMSE and ZTMSE zones. In turn, this is related to the current, superior, thermodynamic reservoir conditions. Based on this, a new geologic approach is proposed to define possible production zones for new wells, relating the ZAH zones to current thermodynamic reservoir conditions. [Spanish] Los factores geologicos son determinantes, tanto para establecer nuevos sitios de perforacion como para determinar el intervalo productor de un pozo nuevo. En el campo geotermico de Cerro Prieto (CGCP) una de los factores mas importantes es la determinacion de las zonas de alteracion hidrotermal (ZAH) que se dividen en dos: zona mineralogica de silice y epidota (ZMSE), sin presencia de CaCO{sub 3}, y zona de transicion mineralogica de silice y epidota (ZTMSE), con presencia de CaCO{sub 3}. Por otra parte, tambien se ha constatado que la continua variacion de las condiciones termodinamicas del yacimiento (temperatura, presion y entalpia) es originada en buena medida por la explotacion del recurso geotermico. La ocurrencia de nuevas condiciones

  10. Evolution of the Cerro Prieto geothermal system as interpreted from vitrinite reflectance under isothermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Barker, C.E. (US Geological Survey, Denver, CO); Pawlewicz, M.J.; Bostick, N.H.; Elders, W.A.

    1981-01-01

    Temperature estimates from reflectance data in the Cerro Prieto system correlate with modern temperature logs and temperature estimates from fluid inclusion and oxygen isotope geothermometry indicating that the temperature in the central portion of the Cerro Prieto System is now at its historical maximum. Isoreflectance lines formed by contouring vitrinite reflectance data for a given isothermal surface define an imaginary surface that indicates an apparent duration of heating in the system. The 250/sup 0/C isothermal surface has a complex dome-like form suggesting a localized heat source that has caused shallow heating in the central portion of this system. Isoreflectance lines relative to this 250/sup 0/C isothermal surface define a zone of low reflectance roughly corresponding to the crest of the isothermal surface. Comparison of these two surfaces suggest that the shallow heating in the central portion of Cerro Prieto is young relative to the heating (to 250/sup 0/C) on the system margins. Laboratory and theoretical models of hydrothermal convection cells suggest that the form of the observed 250/sup 0/C isothermal surface and the reflectance surface derived relative to it results from the convective rise of thermal fluids under the influence of a regional hydrodynamic gradient that induces a shift of the hydrothermal heating effects to the southwest.

  11. Criteria for determining casing depth in Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Olivas M., H.M.; Vaca S., J.M.E.

    1982-08-10

    On the basis of geological data obtained during drilling and its relation to electric logs, together with the problems that arose when drilling through formations until the production zone was reached, it is possible to establish the most suitable manner to line a well and thus formulate an optimum casings program. The main criteria to be taken into consideration in preparing such a program and its application in the drilling of wells programmed in Cerro Prieto to optimize and economize such drilling and achieve suitable techniques for well completion are presented. The criteria are based on the characteristics of the Cerro Prieto field and on casing design factors, as well as a experience gained during drilling in such a field.

  12. Relationship between water chemistry and sediment mineralogy in the Cerro Prieto geothermal field: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Valette-Silver, J.N. (Univ. de Perpignan, France); Thompson, J.M.; Ball, J.W.

    1981-01-01

    The chemical compositions of waters collected from the Cerro Prieto geothermal production wells and hydrothermal emanations are different. Compared to the Cerro Prieto well waters, the surficial waters generally contain significantly less potassium, slightly less calcium and chloride, and significantly more magnesium and sulfate. In comparison to the unaltered sediments, the changes in the mineralogy of the altered sediments appear to be controlled by the type of emanation (well, spring, mud pot, geyser, fumarole, or cold pool). However, an increase in quartz and potassium feldspar percentages seems to be characteristic of the majority of the sediments in contact with geothermal fluids. Preliminary attempts to model the chemical processes occurring in the Cerro Prieto geothermal field using chemical equilibrium calculations are reported. For this purpose the chemical compositions of thermal waters (well and surficial emanation) were used as input data to make calculations with SOLMNEQ and WATEQ2 computer programs. Then the theoretical mineral composition of altered sediments was predicted and compared to the mineralogy actually observed in the solid samples.

  13. Oxygen isotope exchange in rocks and minerals from the Cerro Prieto geothermal system: Indicators of temperature distribution and fluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Williams, A.E.; Elders, W.A.

    1981-01-01

    Oxygen isotopic compositions have been measured in drill cuttings and core samples from more than 40 wells ranging in depth to more than 3.5 km in the Cerro Prieto geothermal field. Profiles of isotopic ratios versus sampling depths provide information on the three-dimensional distribution of temperature and fluid flow. These parameters also indicate variations in the history of hydrothermal processes in different areas of the geothermal field.

  14. Hydrocarbons emissions from Cerro Prieto Geothermal Power Plant, Mexico

    Science.gov (United States)

    Navarro, Karina; Navarro-González, Rafael; de la Rosa, José; Peralta, Oscar; Castro, Telma; Imaz, Mireya

    2014-05-01

    One of the most important environmental issues related to the use of geothermal fluids to generate electricity is the emission of non-condensable gases to the atmosphere. Mexico has one of the largest geothermal plants in the world. The facility is located at Cerro Prieto, Baja California, roughly 30 km south of Mexicali and the international boundary between Mexico and United States. The Cerro Prieto power plant has 13 units grouped on four individual powerhouses. Gas samples from 9 units of the four powerhouses were collected during 4 campaigns conducted in May-July, 2010, February, 2012, December, 2012, and May, 2013. Gas samples from the stacks were collected in 1000 ml Pyrex round flasks with Teflon stopcocks, and analyzed by gas chromatography-mass spectrometry. Methane was the most abundant aliphatic hydrocarbon, with a concentration that ranged from less than 1% up to 3.5% of the total gas mixture. Normal alkanes represented the second most abundant species, and displayed a decreasing abundance with increasing carbon number in the homologous series. Isoalkanes were also present as isobutane and isopentane. Cycloalkanes occurring as cyclopentane and cyclohexane, were detected only at trace level. Unsaturated hydrocarbons (alkenes and alkynes) were not detected. Benzene was detected at levels ranging from less than 1% up to 3.4% of the total gas mixture. Other aromatic hydrocarbons detected were toluene, and xylenes, and were present at lower concentrations (

  15. An overview of the geochemistry of Cerro Prieto geothermal field with emphasis on isotopic changes

    International Nuclear Information System (INIS)

    This paper reviews the global geochemical changes in the Cerro Prieto geothermal reservoir due to exploitation and presents some important conclusions. Distribution of oxygen-18, deuterium, chloride concentrations, enthalpy and geothermometry for the field are presented

  16. Mexican--American cooperative program at the Cerro Prieto Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Witherspoon, P.A.; Espinosa, H.A.; Lippmann, M.J.; Mercado, A.M.; Wollenberg, H.A.

    1978-08-01

    The Cerro Prieto project incorporates studies of the geologic, hydrogeologic, geochemical, and geophysical setting of the geothermal field as well as its structural, reservoir engineering, and subsidence characteristics. A description of the activities involved in each part of this cooperative program is presented. Text of the agreement between the Comision Federal de Electricidad of Mexico and the USERDA for the cooperative study of the Cerro Prieto geothermal field is included.

  17. Progress on the biphase turbine at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Cerini, D.; Hays, L.; Studhalter, W. [Douglas Energy Company, Placentia, CA (United States)

    1997-12-31

    The status of a Biphase turbine power plant being installed at the Cerro Prieto geothermal field is presented. The major modules for the power plant are completed except for a back pressure steam turbine. The power plant will be started in April 1997 with the Biphase turbine alone followed by the addition of the steam turbine module two months later. The current power plant performance level is 2780 kWe due to a decline in the well. An increase in power output to 4060 kWe by adding the flow from another well is planned. The addition of five Biphase power plants with a total power output of 21.2 megawatts is described.

  18. Properties of Cerro Prieto rock at simulated in situ conditions

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, J.F.

    1981-01-01

    Rocks from the Cerro Prieto Geothermal Field were tested under simulated in situ conditions in the laboratory to determine their properties and response to pore pressure reduction as would be caused by reservoir production. The primary purpose of the project was to provide information on compaction and creep as they may contribute to surface subsidence. Results show typical compressibilities for reservoir rocks of about 1 x 10/sup -6/ psi/sup -1/ and creep compaction rates of about 1 x 10/sup -9/ sec/sup -1/ when triggered by 1000 psi pore pressure reduction. This creep rate would cause significant porosity reduction if it continued for several years. Therefore it becomes important to learn how to correctly extrapolate such data to long times.

  19. Basic aspects of the Cerro Prieto reservoir water recharge; Aspectos basicos de la recarga de agua al reservorio de Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, Sergio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    The Cerro Prieto geothermal field, located 30 km South of Mexicali City, Baja California, has at present an installed capacity of 620 MW in geothermal power plants, that operating with endogenous steam, make use of the underground energy by means of deep wells, from which about 80 million cubic meters per year of high enthalpy water and steam mixture are extracted. During the exploitation physical an chemical changes in the hydrothermal fluids discharged by the wells have been detected, which shows, among other things, an elevated water recharge, located towards the West area of the field and a low recharge in the part of the east zone area. For this reason the hot brine waste re-injection is recommended, (previously treated to eliminate the silica excess) to thermally an hydraulically recharge the reservoir in that part of the field. [Espanol] El campo geotermico de Cerro Prieto, situado a 30 km al sur de la ciudad de Mexicali, Baja California, cuenta actualmente, despues de 18 anos en explotacion, con 620 MW de capacidad instalada en plantas geotermoelectricas que, operando con vapor endogeno, aprovechan la energia del subsuelo mediante pozos profundos de los que se extraen alrededor de 80 millones de metros cubicos por ano de una mezcla de agua vapor de elevada entalpia. Durante la explotacion se han percibido cambios fisicos y quimicos en los fluidos hidrotermales descargados por los pozos, lo que indica, entre otras cosas, una recarga elevada de agua localizada hacia el poniente del campo y una recarga baja en una zona de la parte oriental. Por ello se recomienda la reinyeccion de salmuera geotermica caliente de desecho (previamente tratada para eliminar el exceso de silice) para recargar termica e hidraulicamente el reservorio en esa parte del campo.

  20. Results from two years of resistivity monitoring at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Wilt, M.J.; Goldstein, N.E.

    1981-01-01

    Dipole-dipole resistivity measurements for the combined purposes of reservoir delineation and resistivity monitoring were first made at Cerro Prieto in 1978 and have continued on an annual basis since then. Two 20 km long dipole-dipole lines with permanently emplaced electrodes at one kilometer spacings were established over the field area; one of these lines is remeasured annually. Resistivity measurements are taken using a 25 kW generator capable of up to 80A output and a microprocessor controlled signal averaging receiver; this high power-low noise system is capable of highly accurate measurements even at large transmitter-receiver separations. Standard error calculations for collected data indicate errors less than 5% for all points, but 95% confidence intervals show error limits about 2 to 4 times higher. Analysis of collected data indicate little change in the apparent resistivity of the upper 300 m over the field production zone and that in this section measurements are relatively insensitive to the annual rainfall cycle. Apparent resistivity increases were observed over the older producing zone at Cerro Prieto at depths of 1 km and greater. Large zones of decreasing apparent resistivity were observed flanking the zone of increases on both sides. The increase in apparent resistivity in the production region may be due to an increasing fraction of steam in the reservoir resulting from a production related decline in reservoir pressure. Alternatively the increases may be the result of fresh water influx from the Colorado River. The zone of declining resistivity flanking the area of increase may be due to the movement of saline waters into the reservoir region as a result of the pressure decline. Quantitative modeling of observed changes is impractical owing to the high uncertainty in estimating apparent resistivity changes and the nonuniqueness of models.

  1. Radon and ammonia transects across the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Semprini, L.; Kruger, P.

    1981-01-01

    Radon and ammonia transects, conducted at the Cerro Prieto geothermal field, involve measurement of concentration gradients at wells along lines of structural significance in the reservoir. Analysis of four transects showed radon concentrations ranging from 0.20 to 3.60 nCi/kg and ammonia concentrations from 17.6 to 59.3 mg/l. The data showed the lower concentrations in wells of lowest enthalpy fluid and the higher concentrations in wells of highest enthalpy fluid. Linear correlation analysis of the radon-enthalpy data indicated a strong relationship, with a marked influence by the two-phase conditions of the produced fluid. It appears that after phase separation in the reservoir, radon achieves radioactive equilibrium between fluid and rock, suggesting that the phase separation occurs well within the reservoir. A two-phase mixing model based on radon-enthalpy relations allows estimation of the fluid phase temperatures in the reservoir. Correlations of ammonia concentration with fluid enthalpy suggests an equilibrium partitioning model in which enrichment of ammonia correlates with higher enthalpy vapor.

  2. Performance of casings in Cerro Prieto production wells

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez A, B.; Vital B, F.; Bermejo M, F.; Sanchez G, G.

    1981-01-01

    A careful evaluation of different production casings used at Cerro Prieto from 1964 to date has shown that the following casings have yielded particularly impressive results: 7 5/8-in. diameter, J-55, 26 lb/ft; 7 5/8-in. diameter, K-55, 45.3 lb/ft; and 5-in. diameter, K-55, 23.2 lb/ft. These casings differ from others of the same diameter but lighter weight which were also used at the field. The results are favorable in spite of severe construction problems, especially the loss of circulation during cementing operations, which we encountered in some of the wells where these casings were used. The use of gravity-fed fine sand as packing material and the arrangement of the production and intermediate casings were important in avoiding damage due to tension-compression stresses and, above all, damage due to internal or external corrosion over time. This situation is clearly evidenced if we compare the damage to the above casings with that experienced by grade N-80 production casings, especially in a corrosive environment.

  3. Detailed microearthquake studies at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Majer, E.L. (Lawrence Berkeley Lab., CA); McEvilly, T.V.

    1981-01-01

    There appears to be an increase in seismic activity within the Cerro Prieto production zone since early 1978. The microearthquake activity is now more or less constant at a rate of 2 to 3 events per day. The b-values within the field are significantly higher inside the production zone than are those for events on faults outside of the production region. The earthquakes seem to be controlled by the Hidalgo fault, although slight clustering was observed in the center of the main production region. The earthquakes within the production zone may reflect the reservoir dynamics associated with heat and mass withdrawal. Mechanisms such as volume change, thermal stresses and weakening of materials associated with boiling (i.e., phase changes, dissolution) may all be responsible for the increased seismic activity. Although a small reinjection program has started, the pressure drawdown conditions existing within the field would imply that increased pore pressure resulting from the injection activities is not responsible for the increased seismic activity.

  4. Case history report on East Mesa and Cerro Prieto geothermal fields

    Energy Technology Data Exchange (ETDEWEB)

    Davis, DG.; Sanyal, S.K.

    1979-06-01

    Well log analysis as applied to the geothermal industry is one of the areas of technology in great need of further development. One means of improving log analysis technology is to study case histories of the past uses of log analysis as applied to specific fields. The project described in this report involved case history studies on two well-known geothermal areas in North America: the East Mesa field in California and the Cerro Prieto field in Mexico. Since there was considerably more pertinent material available on East Mesa, a major part of the effort on this project was devoted to studying the East Mesa field. One particular problem that first came to attention when studying the Cerro Prieto data was the difficulty in determining actual formation temperature at the time of logging. Since the temperature can have a significant effect on well log readings, an accurate temperature determination was considered to be important.

  5. Areas to explore surrounding the Cerro Prieto geothermal field, BC; Areas para exploracion en los alrededores del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Dumas, Alvaro [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: alvaro.aguilar@cfe.gob.mx

    2009-07-15

    Exploration plays an important role in tapping underground natural resources-whether water, oil, natural gas or minerals. Exploratory data allow us to learn reservoir conditions, increasing probable reserves and reservoir life span. Around the Cerro Prieto geothermal field, BC, and in the Mexicali Valley in general, exploration had almost stopped but recently was resumed by the Studies Division of Comision Federal de ELectricidad (CFE)'s Gerencia de Proyectos Geotermoelectricos. The division sent technical personnel to structurally map the northern and eastern portions of Laguna Salada. The paper offers a general outline of the main zones undergoing exploratory studies-studies perhaps culminating in siting exploratory wells to locate more geothermal resources (and ultimately producing them using binary power plants). CFE also wants to site injection wells west of the current production zone, and this is covered, as well. All activities are meant to increase the productive lifespan of the geothermal reservoir. [Spanish] Cuando se trata de la explotacion de recursos naturales del subsuelo, sea agua, gas, petroleo o minerales, la exploracion juega un papel muy importante, ya que permite conocer las condiciones del yacimiento que pudieran llevar a incrementar las reservas de los recursos explotados y extender su vida util. En las zonas aledanas al campo geotermico de Cerro Prieto, BC, y en general en el Valle de Mexicali, la exploracion estaba practicamente detenida habiendose reactivado a raiz de que la Subgerencia de Estudios de la Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad (CFE) envio personal para realizar mapeos estructurales en las porciones norte y oriente de la Laguna Salada. Este trabajo presenta un panorama general de las areas prioritarias para realizar estudios exploratorios y poder programar, con mas bases, pozos exploratorios enfocados a localizar mas recursos geotermicos, inclusive para generar energia por medio

  6. Hydraulic model and steam flow numerical simulation of the Cerro Prieto geothermal field, Mexico, pipeline network

    International Nuclear Information System (INIS)

    The development of a hydraulic model and numerical simulation results of the Cerro Prieto geothermal field (CPGF) steam pipeline network are presented. Cerro Prieto is the largest water-dominant geothermal field in the world and its transportation network has 162 producing wells, connected through a network of pipelines that feeds 13 power-generating plants with an installed capacity of 720 MWe. The network is about 125 km long and has parallel high- and low-pressure networks. Prior to this study, it was suspected that steam flow stagnated or reversed from its planned direction in some segments of the network. Yet, the network complexity and extension complicated the analysis of steam transport for adequate delivery to the power plants. Thus, a hydraulic model of the steam transportation system was developed and implemented numerically using an existing simulator, which allowed the overall analysis of the network in order to quantify the pressure and energy losses as well as the steam flow direction in every part of the network. Numerical results of the high-pressure network were obtained which show that the mean relative differences between measured and simulated pressures and flowrates are less than 10%, which is considered satisfactory. Analysis of results led to the detection of areas of opportunity and to the recommendation of changes for improving steam transport. A main contribution of the present work is having simulated satisfactorily the longest (to our knowledge), and probably the most complex, steam pipeline network in the world. - Highlights: • Extensive literature review of flow models of geothermal steam gathering networks. • Hydraulic model of the Cerro Prieto geothermal field steam network. • Selection and validation of the employed pressure-drop model. • Numerical flow simulation of the world's largest geothermal steam gathering network. • Detailed network pressure drop analysis and mapping of steam flow distribution

  7. Two-dimensional modeling of apparent resistivity pseudosections in the Cerro Prieto region

    Energy Technology Data Exchange (ETDEWEB)

    Vega, R.; Martinez, M.

    1981-01-01

    Using a finite-difference program (Dey, 1976) for two-dimensional modeling of apparent resistivity pseudosections obtained by different measuring arrays, four apparent resistivity pseudosections obtained at Cerro Prieto with a Schlumberger array by CFE personnel were modeled (Razo, 1978). Using geologic (Puente and de la Pena, 1978) and lithologic (Diaz, et al., 1981) data from the geothermal region, models were obtained which show clearly that, for the actual resistivity present in the zone, the information contained in the measured pseudosections is primarily due to the near-surface structure and does not show either the presence of the geothermal reservoir or the granitic basement which underlies it.

  8. Extension of the Cerro Prieto field and zones in the Mexicali Valley with geothermal possibilities in the future

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca L, H.L.; de la Pena L, A.; Puente C, I.; Diaz C, E.

    1981-01-01

    This study concerns the possible extension of the Cerro Prieto field and identification of other zones in the Mexicali Valley with geothermal development potential by assessing the structural geologic conditions in relation to the regional tectonic framework and the integration of geologic and geophysical surveys carried out at Cerro Prieto. This study is based on data obtained from the wells drilled to date and the available geological and geophysical information. With this information, a geologic model of the field is developed as a general description of the geometry of what might be the geothermal reservoir of the Cerro Prieto field. In areas with geothermal potential within the Mexicali Valley, the location of irrigation wells with anomalous temperatures was taken as a point of departure for subsequent studies. Based on this initial information, gravity and magnetic surveys were made, followed by seismic reflection and refraction surveys and the drilling of 1200-m-deep multiple-use wells. Based on the results of the final integration of these studies with the geology of the region, it is suggested that the following areas should be explored further: east of Cerro Prieto, Tulecheck, Riito, Aeropuerto-Algodones, and San Luis Rio Colorado, Sonora.

  9. Minimal thermodynamic conditions in the reservoir to produce steam at the Cerro Prieto geothermal field, BC; Condiciones termodinamicas minimas del yacimiento para producir vapor en el campo geotermico de Cerro Prieto, B.C.

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Rodriguez; Marco Helio [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: marco.rodriguez01@cfe.gob.mx

    2009-01-15

    Minimal thermodynamic conditions in the Cerro Prieto geothermal reservoir for steam production are defined, taking into account the minimal acceptable steam production at the surface, considering a rank of mixed-enthalpies for different well-depths, and allowing proper assessments for the impacts of the changes in fluid reservoir pressure and enthalpy. Factors able to influence steam production are discussed. They have to be considered when deciding whether or not to drill or repair a well in a particular area of the reservoir. These evaluations become much more relevant by considering the huge thermodynamic changes that have occurred at the Cerro Prieto geothermal reservoir from its development, starting in 1973, which has lead to abandoning some steam producing areas in the field. [Spanish] Las condiciones termodinamicas minimas del yacimiento geotermico de Cerro Prieto, BC, para producir vapor se determinan tomando en cuenta la minima produccion de vapor aceptable en superficie, considerando un rango de entalpias de la mezcla y para diferentes profundidades de pozos, lo que permite valorar adecuadamente el impacto de la evolucion de la presion y entalpia del fluido en el yacimiento. Se discuten los factores que pueden afectar la produccion de vapor, los cuales se deben tomar en cuenta para determinar la conveniencia o no de perforar o reparar un pozo en determinada zona del yacimiento. Estas evaluaciones adquieren gran relevancia al considerar los enormes cambios termodinamicos que ha presentado el yacimiento geotermico de Cerro Prieto, como resultado de su explotacion iniciada en 1973, lo que ha llevado a abandonar algunas zonas del campo para la produccion de vapor. Palabras Clave: Cerro Prieto, entalpia, evaluacion de yacimientos, politicas de explotacion, presion, produccion de vapor.

  10. Temperature distribution in the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Castillo B, F.; Bermejo M, F.J.; Domiguez A, B.; Esquer P, C.A.; Navarro O, F.J.

    1981-01-01

    A series of temperature and pressure logs and flow rate measurements was compiled for each of the geothermal wells drilled to different reservoir depths between October 1979 and December 1980. Based on the valuable information obtained, a series of graphs showing the thermal characteristics of the reservoir were prepared. These graphs clearly show the temperature distribution resulting from the movement of fluids from the deep regions toward the higher zones of the reservoir, thus establishing more reliable parameters for locating new wells with better production zones. Updated information based on data from new deep wells drilled in the geothermal field is presented here. This new information does not differ much from earlier estimates and theories. However, the influence of faulting and fracturing on the hydrothermal recharge of the geothermal reservoir is seen more clearly.

  11. Presence of cross flow in the Cerro Prieto geothermal field, BC; Presencia de flujo cruzado en el campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Rodriguez, Marco Helio [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: marco.rodriguez01@cfe.gob.mx

    2011-01-15

    During the development of Cerro Prieto geothermal field, BC, exploitation has increased gradually, causing a continuous drop in pressure to almost 100 bars in the central and eastern parts of the field. This has occurred despite the high natural recharge induced by the reservoir exploitation and helped by the high permeability of the reservoir and the wide availability of natural recharge of low-temperature water in the vicinity. The strata above the production zones have significantly lower temperatures than these zones, but due to the particular characteristics of the reservoir, do not have pressure drops. As the pressure of producing strata declines, the hydraulic pressure differential between them and the overlying strata increases. Thus in recent years the phenomenon of cross flow occurs with greater frequency and severity. In this paper, this phenomenon is analyzed, detailing the specific mechanisms favoring it and identifying the stage (drilling or workover) in which it commonly occurs. Rigorous supervision during these stages is crucial to identifying cross flow and to taking necessary measures to save the well. Cross flow cases are presented at different stages in the history of a well: during drilling, repair, before and during the stimulation, and during production. [Spanish] Durante el desarrollo del campo geotermico de Cerro Prieto, BC, la explotacion se ha incrementado en forma gradual provocando una continua caida de presion, que en las porciones central y oriente ha sido de casi 100 bars. Esto ha ocurrido a pesar de la enorme recarga natural inducida por la explotacion, favorecida por la alta permeabilidad del yacimiento y la gran disponibilidad de recarga natural de agua de baja temperatura en los alrededores del mismo. Los estratos ubicados encima de las zonas productoras presentan temperaturas significativamente menores que estos, pero debido a las caracteristicas particulares del yacimiento, no han presentado abatimiento en su presion. En la

  12. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mazor, E. (Weizmann Inst. of Science, Rehovot, Israel); Truesdell, A.H.

    1981-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He, /sup 40/Ar) and atmospheric noble gases (Ne, Ar, and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic helium and argon-40 formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 to 3%) and mixing with shallow cold water occurred (0 to 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 to 3% steam separation and complement other tracers, such as Cl or temperature, which are effective only beyond this range.

  13. Did stresses from the Cerro Prieto Geothermal Field influence the El Mayor-Cucapah rupture sequence?

    Science.gov (United States)

    Trugman, Daniel T.; Borsa, Adrian A.; Sandwell, David T.

    2014-12-01

    The Mw 7.2 El Mayor-Cucapah (EMC) earthquake ruptured a complex fault system in northern Baja California that was previously considered inactive. The Cerro Prieto Geothermal Field (CPGF), site of the world's second largest geothermal power plant, is located approximately 15 km to the northeast of the EMC hypocenter. We investigate whether anthropogenic fluid extraction at the CPGF caused a significant perturbation to the stress field in the EMC rupture zone. We use Advanced Land Observing Satellite interferometric synthetic aperture radar data to develop a laterally heterogeneous model of fluid extraction at the CPGF and estimate that this extraction generates positive Coulomb stressing rates of order 15 kPa/yr near the EMC hypocenter, a value which exceeds the local tectonic stressing rate. Although we cannot definitively conclude that production at the CPGF triggered the EMC earthquake, its influence on the local stress field is substantial and should not be neglected in local seismic hazard assessments.

  14. Bottom Topography, Recent Sedimentation and Water Volume of the Cerro Prieto Dam, NE Mexico

    Science.gov (United States)

    Yutsis, V. V.

    2012-12-01

    Cerro Prieto dam, relatively small water reservoir in the NE of Mexico, is characterized by a very high velocity of recent sedimentation, irregular bottom topography and sub-bottom seepage. Very high resolution seismic study using non-linear parametric echo sounder SES-2000 was carried out in this water reservoir, which is one of the main resources of potable water for the Monterrey, the city with a population of about four million inhabitants. A strong difference between water depth and hence the volume capacity calculated by National Commission of Water (Comision Nacional del Agua, CNA), Digital Elevation Model (DEM), and acoustic data was discovered. Very high rate of recent sedimentation due to damming is discussed. SES data interpretation shows that the thickness of recent sediments due to siltation of the reservoir reaches 3.5-4.0 m. Differences between the CNA and SES data indicate storage losses from 8-10 up to 30 million cubic meters due to sedimentation.

  15. Comments on some of the drilling and completion problems in Cerro Prieto geothermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez A, B.; Sanchez G, G.

    1981-01-01

    From 1960 to the present, 85 wells with a total drilling length exceeding 160,000 m have been constructed at Cerro Prieto, a modest figure compared to an oil field. This activity took place in five stages, each characterized by changes and modifications required by various drilling and well-completion problems. Initially, the technical procedures followed were similar to those used in the oil industry. However, several problems emerged as a result of the relatively high temperatures found in the geothermal reservoir. The various problems that have been encountered can be considered to be related to drilling fluids, cements and cementing operations, lithology, geothermal fluid characteristics, and casings and their accessories. As the importance of high temperatures and the characteristics of the geothermal reservoir fluids were better understood, the criteria were modified to optimize well-completion operations, and satisfactory results have been achieved to date.

  16. Report of the seismic activity at the Cerro Prieto B.C., Mexico, geothermal field during 1996; Reporte de la actividad sismica registrada en el campo geotermico de Cerro Prieto, B.C., Mexico, durante 1996

    Energy Technology Data Exchange (ETDEWEB)

    Escamilla Hernandez, Abelardo [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)

    1997-05-01

    In February 1996 started the operation of the Seismic Network of Cerro Prieto Geothermal Field (RESICP). It is constituted by five digital stations with velocity sensors of three components and a natural period of one second. The network worked continuously until December 2, 1996. During this period, we located 270 events in the field area and its neighborhood, with coda-length magnitude 1Cerro Prieto Dos and Cerro Prieto Tres. The recorded activity is less than in Zone A, focal depths are between five and seven km, and the coda- length magnitude is 1Cerro Prieto volcano and to the NW of it. The activity was of swarm type mainly, and inside this zone was recorded the greater event for the region (M{sub c}=4.21, 30 August at 06:245 Universal Time), coda-length magnitude 1 Cerro Prieto (RESICP); consta de cinco estaciones de tipo digital, sensores de velocidad de tres componentes, y periodo natural de un segundo. Trabajo en forma ininterrumpida hasta el 2 de diciembre de 1996. Durante ese periodo se localizaron

  17. Corrosion in pipelines and well casings at the Cerro Prieto geothermal field, BC; Corrosion en tuberias de linea y de revestimiento de pozos del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Herrera, Carlos A.; Canchola Felix, Ismael; Raygoza Flores, Joaquin; Mora Perez, Othon [Comision Federal de Electricidad, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: carlos.miranda02@cfe.gob.mx

    2009-07-15

    In the area called Poligono Hidalgo, inside the Cerro Prieto IV zone in the Cerro Prieto geothermal field, BC, corrosion has occurred in the last few years on well casings and pipelines used for geothermal fluids. Corrosion test results are presented here for pipes, type API L-80 and ASTM A-53 grade B, which were subjected to condensate from wells 403 and 424. These wells have thrown corroded material from their respective casings. With these data we pinpoint corrosive conditions in this field area and determine which pipes are adequate to case wells in similar chemical, production conditions to minimize adverse effects and extend the life of the well, allowing more efficient exploitation of the deepest production zones in the reservoir. [Spanish] En el campo geotermico de Cerro Prieto, BC, dentro del area del Poligono Hidalgo en el sector conocido como Cerro Prieto IV, algunos pozos han presentado en los ultimos anos desgastes en sus tuberias de revestimiento y en las tuberias de linea para el transporte del fluido geotermico. Se presentan resultados de pruebas de corrosion con tuberias tipo API L-80 y ASTM A-53 grado B al ser sometidas al condensado de los pozos 403 y 424, los cuales han estado arrojando material de sus respectivas tuberias de revestimiento. Con estos datos se pretende conocer las condiciones corrosivas de esa zona del campo y determinar cual seria la tuberia ideal a utilizar en pozos con condiciones quimicas de produccion semejantes a fin de minimizar este efecto adverso y prolongar la vida de los pozos, a la vez que se permita la explotacion eficiente de las zonas productoras mas profundas del yacimiento.

  18. Oxygen isotope exchange in rocks and minerals from the Cerro Prieto geothermal system: indicators of temperature distribution and fluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Williams, A.E.; Elders, W.A.

    1981-01-01

    Oxygen isotopic compositions have been measured in drill cuttings and core samples from more than 40 wells ranging in depth to more than 3.5 km in the Cerro Prieto geothermal field. Oxygen isotopic profiles of pore-filling calcites in sandstones appear to be a reliable measure of the recent equilibrium temperature distribution in the field before production began. From these data, a detailed, three-dimensional map has been developed, showing the equilibrium temperatures in the geothermal field. A mass balance calculation has been performed using measured /sup 18/O enrichment of the geothermal brine. This calculation implies an overall water; rock volume ratio of approximately 3:1 during the history of the Cerro Prieto system. Paleotemperatures different from the present thermal regime have been studied by examining coexisting mineral systems which exchanged their oxygen with the geothermal brines at different rates.

  19. Soil mercury levels in the area surrounding the Cerro Prieto geothermal complex, MEXICO.

    Science.gov (United States)

    Pastrana-Corral, M A; Wakida, F T; García-Flores, E; Rodriguez-Mendivil, D D; Quiñonez-Plaza, A; Piñon-Colin, T D J

    2016-08-01

    Even though geothermal energy is a renewable energy source that is seen as cost-effective and environmentally friendly, emissions from geothermal plants can impact air, soil, and water in the vicinity of geothermal power plants. The Cerro Prieto geothermal complex is located 30 km southeast of the city of Mexicali in the Mexican state of Baja California. Its installed electricity generation capacity is 720 MW, being the largest geothermal complex in Mexico. The objective of this study was to evaluate whether the emissions generated by the geothermal complex have increased the soil mercury concentration in the surrounding areas. Fifty-four surface soil samples were collected from the perimeter up to an approximate distance of 7660 m from the complex. Additionally, four soil depth profiles were performed in the vicinity of the complex. Mercury concentration in 69 % of the samples was higher than the mercury concentration found at the baseline sites. The mercury concentration ranged from 0.01 to 0.26 mg/kg. Our results show that the activities of the geothermal complex have led to an accumulation of mercury in the soil of the surrounding area. More studies are needed to determine the risk to human health and the ecosystems in the study area. PMID:27418073

  20. Update of the basement model of the Cerro Prieto, B. C., geothermal field, Mexico; Actualizacion del modelo del basamento en el campo geotermico de Cerro Prieto, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Lopez, Macario [Residencia General de Cerro Prieto, Comision Federal de Electricidad, Mexicali, Baja California (Mexico)

    1999-04-01

    With the aim to actualize the basement model of the Cerro Prieto Geothermal Field, a gravity interpretation has been held. We modeled in 2.5 D, nine profiles traced over the Bouguer anomaly map. Well data concerning lithology and density changes were used to fit the gravity models. Results of this work confirm that the geometry of the basement of Cerro Prieto, corresponds to a structural sequence. From west to east it starts as a big depression, continues with a strong uplift of the basement in the middle sector and finally deepens eastward in steps. The basement model proposed in the present work, defines a similar trend to that established by Fonseca y Razo (1980), but there are differences in basement depth in some areas. In the present model we interpret basement depths between 200 and 400 m deeper than in previous models to the south and northwest of the actual exploitation zone. [Spanish] Con el fin de actualizar el modelo del basamento en el Campo Geotermico de Cerro Prieto, se realizo una reinterpretacion gravimetrica, modelando en 2.5 D, 9 perfiles trazados sobre el mapa de anomalia de Bouguer. Utilizando la informacion litologica obtenida a traves de numerosas perforaciones profundas, se hicieron coincidir, dentro de los mofelos gravimetricos, las principales variaciones litologicas con cambios en la densidad. Los resultados de este trabajo reiteran que la geometria del basamento del Campo de Cerro Prieto, vista de W a E, corresponde con una secuencia estructural que se inicia con una gran depresion en el W, continua con un fuerte levantamiento y finalmente se extiende con una tendencia a profundizarse hacia el E de forma escalonada. El modelo de basamento derivado del presente trabajo, define una tendencia muy similar al modelo de basamento establecido (Fonseca y Razo, 1980), pero difiere en cuanto a la profundidad en algunos sectores del campo. En el actual trabajo se interpreta una profundidad entre 200 y 400 m mayor hacia el sur y noroeste de la

  1. Evolution of the CP-I sector of the Cerro Prieto geothermal reservoir, BC, and exploitation alternatives; Evolucion del sector CP-I del yacimiento geotermico de Cerro Prieto, BC, y alternativas de explotacion

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Rodriguez, Marco Helio [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: marco.rodriguez01@cfe.gob.mx

    2010-01-15

    After 35 years of exploitation of the CP-I (Cerro Prieto I) sector of the Cerro Prieto geothermal field, its thermal conditions have been declined substantially; the number of production wells is reduced and exploitation has been abandoned in some zones. However with a binary cycle, it is still possible to generate electricity from the remaining reservoir energy. To do so, one needs to know a detailed reservoir history of the sector, identifying the best potential strata to be assessed. In this paper, the CP-I reservoir evolution is presented and its exploitation and main reservoir characteristics -which play important roles- are identified. The CP-I zones offering the best conditions for binary cycle exploitation are identified. Exploiting partially abandoned reservoir sections is crucial for the future of the field. If such sections can be made to produce, this will help reduce the progressive steam-production decline in the occurring since production began. The production decline had been mitigated by a large area available for drilling replacement production wells, but such an area is limited now, due to the vast number of operating wells. [Spanish] Despues de 35 anos de explotacion del yacimiento en el sector de CP-I (Cerro Prieto I) del campo geotermico de Cerro Prieto, BC, sus condiciones termicas han declinado considerablemente, por lo que el numero de pozos productores ha disminuido, dejando algunas zonas abandonadas a la explotacion. Sin embargo, aun es posible aprovechar la energia que contiene este sector del yacimiento para la generacion de electricidad mediante ciclo binario. Para ello primeramente se debe conocer en detalle cual ha sido la evolucion del yacimiento en este sector, identificando los estratos de mejor potencial para evaluarlos posteriormente. En este estudio se presenta la evolucion del yacimiento de CP-I como respuesta a su explotacion, identificando las principales caracteristicas del yacimiento que determinan su comportamiento. Asi

  2. Criteria to determine the depth of the production interval in wells of the Cerro Prieto geothermal field, Mexico; Criterios para determinar la profundidad del intervalo productor en pozos del campo geotermico de Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Leon Vivar, Jesus Saul de [Comision Federal de Electricidad, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)]. E-mail: jesus.deleon@cfe.gob.mx

    2006-07-15

    Ways to select the depth of the production interval or to complete wells in the Cerro Prieto geothermal field have changed during the development of the field. From 1961 when drilling began to the middle of 2005, a total of 325 wells were drilled. The paper compares the approaches used in the past with those of the last ten years. The Cerro Prieto system has been classified as being of liquid-dominated and high-temperature. Today, after 33 years of commercial exploitation, it has experienced a series of thermal and geochemical fluid changes making it necessary to modify the ways to select the depth of the well production intervals, according to the observed behavior of the reservoir. The new criteria include the thermal approach, the geological approach, the geochemical approach and a comparative approach with neighboring wells. If most of these criteria are interpreted correctly, the success of a well is ensured. [Spanish] Los criterios para seleccionar la profundidad del intervalo productor o la terminacion de los pozos en el campo geotermico de Cerro Prieto han cambiado durante el desarrollo del mismo. De 1961, cuando se perforaron los primeros pozos, hasta mediados del 2005 se han perforado un total de 325 pozos. En el presente articulo se hara una breve revision de cuales han sido los criterios usados en el pasado y los que se han venido empleando en los ultimos diez anos. El yacimiento de Cerro Prieto ha sido clasificado como de liquido dominante, de alta temperatura, pero actualmente, despues de 33 anos de explotacion comercial, ha sufrido una serie de cambios termicos y geoquimicos en sus fluidos, por lo que ha sido necesario modificar los criterios para seleccionar la profundidad del intervalo productor de los pozos de acuerdo al comportamiento observado en el yacimiento. Los criterios actuales se dividen en cuatro: 1. Criterio termico, 2. Criterio geologico, 3. Criterio geoquimico y 4. Criterio comparativo de los pozos vecinos. Cuando la mayoria de estos

  3. Production induced boiling and cold water entry in the Cerro Prieto geothermal reservoir indicated by chemical and physical measurements

    Energy Technology Data Exchange (ETDEWEB)

    Grant, M.A. (DSIR, Wellington, New Zealand); Truesdell, A.H.; Manon, A.

    1981-01-01

    Chemical and physical data suggest that the relatively shallow western part of the Cerro Prieto reservoir is bounded below by low permeability rocks, and above and at the sides by an interface with cooler water. There is no continuous permeability barrier around or immediately above the reservoir. Permeability within the reservoir is dominantly intergranular. Mixture with cooler water rather than boiling is the dominant cooling process in the natural state, and production causes displacement of hot water by cooler water, not by vapor. Local boiling occurs near most wells in response to pressure decreases, but no general vapor zone has formed.

  4. Vertical movement along the Cerro Prieto transform fault, Baja California, Mexico - a mechanism for geothermal energy renewal

    Energy Technology Data Exchange (ETDEWEB)

    Vonder Haar, S.; Noble, J.E.; Puente Cruz, I.

    1979-03-01

    Data from 53 geothermal wells to depths of 1 to 3 km on either side of the right-lateral Cerro Prieto fault, as well as geophysical data, indicate vertical displacements of this fault of 400 to 600 m. This episoidic vertical movement has offset deltaic sandstone reservoirs that are primarily at 1200 m and 1800 m depth and contain 250{sup 0} to 345{sup 0}C water. A major fracture system for convective fluid movement has been thus maintained, with production at 150 MW.

  5. Changes in steam production due to the reservoir conditions in Cerro Prieto, Baja California; Cambios en la produccion de vapor debido a las condiciones del yacimiento en Cerro Prieto, Baja California

    Energy Technology Data Exchange (ETDEWEB)

    Morales Cardenas, Ramon; Rodriguez Rodriguez, Marco H. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)]. E-mail: marco.rodriguez01@gfe.gob.mx

    2011-07-15

    In more than 35 years of exploitation, thermodynamic conditions have changed in the Cerro Prieto geothermal reservoir. The effects are analyzed of the changes to the reservoir and their consequences to steam production in different field zones. For steam production, the most important features of reservoir fluids are enthalpies and pressures. The evolution of these features is presented in an enthalpy-pressure diagram. Here it can be seen that some reservoir zones have almost reached abandonment conditions. [Spanish] En mas de 35 anos de explotacion el yacimiento geotermico de Cerro Prieto ha experimentado cambios en sus condiciones termodinamicas. En este trabajo se analiza el efecto de esos cambios del yacimiento y su repercusion en la produccion de vapor para las diferentes zonas en las que se ha dividido el campo. Las propiedades mas importantes del fluido en el yacimiento para la produccion de vapor son su entalpia y su presion, por lo que se presenta la evolucion de esas propiedades en un diagrama de presion-entalpia, en el que se observa que hay zonas del yacimiento que estan proximas a alcanzar condiciones de abandono.

  6. Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.

    Energy Technology Data Exchange (ETDEWEB)

    Sarychikhina, O; Glowacka, E; Mellors, R; Vidal, F S

    2011-03-03

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

  7. Hydraulic model of the steam-lines network of the Cerro Prieto, B.C., geothermal field; Modelo hidraulico de la red de vaporductos del campo geotermico de Cerro Prieto, B.C.

    Energy Technology Data Exchange (ETDEWEB)

    Salaices, E; Garcia, A; Martinez J I; Ovando, R; Cecenas, M; Hernandez A F [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: salaices@iie.org.mx; Canchola, I; Mora, O; Miranda, C; Herandez, M; Lopez, S; Murillo, I [Comision Federal de Electricidad, B.C (Mexico)

    2007-01-15

    The steam-line network of the Cerro Prieto geothermal field is composed of 184 wells, and 162 of the wells are integrated and connected by pipes. Thirteen power units, with an installed electrical capacity of 720 MW, are fed by that network. The network length is 120 km, including pipes of several diameters with branches and interconnections. The extension and complexity of the steam-line system make it difficult to analyze the transport and supply of steam to the power plants. For that it was necessary to have a tool capable of analyzing the system and the performance of the network as a whole, as well as the direction and flow volumes in each part of the system. In this paper, a hydraulic model of the Cerro Prieto steam-line network is presented. The model can determine the performance of the whole network by quantifying the pressure drops, flows and heat losses of the components. The model analyses the consequences of changes in operating conditions, steam production, maintenance activities and design (such as the integration of new wells). The model was developed using PIPEPHASE 9.0, a numeric simulator of multi-phase flow in steady state with heat transfer. It is used to model systems and pipe networks for steam- and condensate-transport. [Spanish] La red de vaporductos del campo geotermico de Cerro Prieto esta compuesta por un conjunto de 184 pozos, de los cuales 162 son pozos integrados, interconectados entre si a traves de una red de tuberias. Por medio de esta red se alimentan 13 unidades generadoras de electricidad con una capacidad total instalada de 720 MWe. La red tiene una longitud aproximada de 120 kilometros y esta compuesta por tuberias de diferentes diametros, ramales, interconexiones, etc. La complejidad y extension del sistema de vaporductos hace muy dificil el analisis del transporte y suministro de vapor a las plantas generadoras. Lo anterior creo la necesidad de contar con una herramienta que ayudara en el analisis del sistema con el fin de

  8. Cost model for geothermal wells applied to the Cerro Prieto geothermal field case, BC Abstract; Modelo de costeo de pozos geotermicos aplicado para el caso del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Vaca Serrano, Jaime M.E [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: jaime.vaca@cfe.gob.mx

    2008-01-15

    A project for drilling geothermal wells to produce electrical energy can be defined as a sequence of plans to get steam or geothermal fluids to satisfy a previously known demand, and, under the best possible conditions, to obtain payment. This paper presents a cost model for nine wells drilled at the Cerro Prieto geothermal field in 2005 and 2006 to supply steam to the power plants operating in the field. The cost model is based on the well cost, the initial steam production, the annual decline of steam, the drilling schedule and the break-even point for each well. The model shows the cost of steam by the ton and the sale price needed to determine the discount rate and the investment return time. [Spanish] Un proyecto de perforacion de pozos geotermicos puede definirse como una secuencia o sucesion de planes para obtener vapor o fluidos geotermicos destinados a satisfacer una demanda previamente determinada, que se emplearan principalmente para generar energia electrica, bajo las mejores condiciones para obtener un pago. Este trabajo presenta un modelo de costeo para nueve pozos en el campo geotermico de Cerro Prieto, que fueron perforados entre 2005 y 2006 como parte del suministro de vapor para las plantas generadoras que operan en este campo. El modelo de costeo se basa en el costo por pozo, la produccion inicial de vapor, la declinacion anual de vapor, los intereses de las obras de perforacion y el punto de equilibrio para cada pozo. Los resultados permiten conocer el costo de la tonelada de vapor y el precio de venta para determinar la tasa de descuento y el tiempo de retorno de la inversion.

  9. Noise reduction in steam-vent points at the Cerro Prieto geothermal field, BC; Reduccion del ruido en puntos de desfogue en el campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Herrera, Carlos A [Comision Federal de Electricidad, Residencia General de Cerro Prieto, Mexicali, B.C (Mexico)]. E-mail: carlos.miranda02@cfe.gob.mx

    2008-01-15

    Steam silencers have been placed on the power units regulation system of the Cerro Prieto geothermal field, but not where the steam-pipes vent high-pressure steam (rupture disks). Moreover, the power-unit silencers are large and their abilities to reduce noise depend on an external, uncontrollable factor: pores sizes in the volcanic rocks they are made of. Thus a compact, economic and relatively easy to construct metallic silencer was designed to be used at several points of dry-steam venting to minimize the noise. The design was based on orifice-plate equations and a prototype was constructed and tested. It proved capable of reducing noise by 30 decibels for atmospheric discharges of primary steam at operating pressures. The size of the silencer can be adjusted to the particular needs of each vent case. [Spanish] En el campo geotermico de Cerro Prieto solo existen silenciadores de vapor en el sistema de regulacion de las plantas generadoras, pero no en los sitios de desfogue de vapor a alta presion en los vaporductos (discos de ruptura). Ademas, los silenciadores de las plantas son muy robustos y su capacidad de reduccion del ruido depende de un factor externo no controlable, como es el tamano del poro de la roca volcanica con el que estan construidos. Por lo tanto, se diseno un silenciador metalico compacto, economico y relativamente facil de fabricar, para utilizarse en diversos puntos de descarga de vapor seco a fin de minimizar el ruido. El diseno se realizo con base en las ecuaciones de la placa de orificio. Se construyo un prototipo cuyas pruebas demostraron que es capaz de reducir el ruido hasta en 30 decibeles, al descargar desde la presion de operacion de vapor primario hacia la presion atmosferica. Las dimensiones del silenciador pueden ajustarse a las necesidades particulares de cada caso de desfogue.

  10. Two-phase characteristics of the feeding fluid of Cerro Prieto IV wells (Mexico) obtained by gas equilibrium; Caracteristicas bifasicas del fluido de alimentacion de pozos de Cerro Prieto IV (Mexico), obtenidas por equilibrio gaseoso

    Energy Technology Data Exchange (ETDEWEB)

    Barragan-Reyes, Rosa Maria; Arellano-Gomez, Victor Manuel; Portugal-Marin, Enrique [Instituto de Investigaciones Electricas (Mexico); De Leon-Vivar, Jesus [Comision Federal de Electricidad, Residencia General de Cerro Prieto, B.C (Mexico)

    2008-10-15

    The gas composition of fluids produced by CP IV geothermal wells from the Cerro Prieto field was studied in order to identify different types of fluids entering the wells by estimating their temperature and excess steam. A method based on the Fischer Tropsch reaction and H2S equilibrium with pyrite-pyrrhotite as mineral buffer (FTHSH3) was used. The results for the reservoir natural state indicated the presence of fluids with heterogeneous reservoir temperature (between 275 and 310 degrees Celsius) and excess steam values, which were found from negative (boiled liquid that has lost steam when flowing to the well) to one (steam phase with zero liquid saturation). The study for individual wells in which boiling processes were identified, showed that through time, the feeding fluids consist of a two-phase mixture with different liquid/steam proportions. Also, the results suggested that a steam phase could occur at CP IV which is added to the feeding fluid, depending on the operation conditions of the wells. The origin of this steam could be the boiling of the deeper liquid due to a pressure drop. [Spanish] Se estudio la composicion gaseosa de los fluidos producidos por pozos geotermicos del sector CP IV del campo de Cerro Prieto para tratar de distinguir aportes de fluidos diferentes mediante la estimacion de su temperatura de yacimiento y del exceso de vapor. Se utilizo un metodo de equilibrio gaseoso basado en la reaccion de Fischer Tropsch y el equilibrio combinado pirita-pirrotita (FT-HSH3). Los resultados obtenidos indican que en el estado inicial del yacimiento existen fluidos que muestran heterogeneidad en los valores de temperatura de yacimiento (entre 275 y 310 grados Celsius), asi como en el exceso de vapor con valores desde negativos (liquido que despues de ebullir ha perdido vapor en su trayecto hacia el pozo) hasta uno (vapor con cero saturacion de liquido). El estudio individual de los pozos con fenomenos de ebullicion muestra que a traves del tiempo

  11. Geological and production analyses focused on exploration of the eastern part of the Cerro Prieto geothermal field, BC; Analisis geologico-productivo enfocado a la exploracion de la parte oriental del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Dumas, Alvaro [Comision Federal de Electricidad, Residencia General de Cerro Prieto, B.C (Mexico)]. E-mail: alvaro.aguilar@cfe.gob.mx

    2008-01-15

    The eastern part of the Cerro Prieto geothermal field (CGCP), known as Poligono Nuevo Leon, is an area with proven geothermal resources, as confirmed by seven directional wells located toward the east and by vertical well M-200 located inside the polygon. Well M-200 was drilled in 1984 and has produced about 4 million tons of steam to date. It is integrated into the CP-2 sector, producing 68 t/h of steam. Presently the eastern part of CGCP, representing 25% of the total field area, is producing over half of the steam for the entire field. In the last few years, the steam has come only after increasing the number of production wells located in the eastern zone of CGCP (Rodriguez, 2006), where pressure, enthalpy and temperature conditions are better than in other parts of the field. However in the long term it will be necessary to incorporate Poligono Nuevo Leon into the productive area to expand the productive life of CGCP. This paper includes a geological analysis, plus models for steam production, temperature and enthalpy for Poligono Nuevo Leon. [Spanish] La parte oriental del Campo Geotermico de Cerro Prieto (CGCP), conocida como Poligono Nuevo Leon, representa una area potencial con recursos geotermicos comprobados, lo que demuestran siete pozos direccionales que se han perforado hacia el este, asi como el pozo vertical M-200, localizado dentro del poligono. El pozo M-200 se perforo en 1984 y ha producido a la fecha alrededor de 4 millones de toneladas de vapor, estando integrado al sector CP-2 una produccion de 68 t/h de vapor. Actualmente la parte oriental del CGCP, que representa el 25% del area total del campo, produce mas de la mitad del total de vapor del campo. El suministro de vapor en los ultimos anos se ha logrado cubrir aumentando el numero de pozos en operacion localizados en la zona oriente del CGCP (Rodriguez, 2006), ya que es aqui donde hay condiciones de presion, entalpia y temperatura del yacimiento que son mejores que en otras areas del campo

  12. Studies for recovering injection capacity in wells of the Cerro Prieto, BC, geothermal field; Estudios para recuperar la capacidad de aceptacion en pozos inyectores del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Rosales, Julio [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: julio.alvarez@cfe.gob.mx

    2010-01-15

    As in geothermal fields around the world, at Cerro Prieto geothermal field, Baja California, former exploratory and production wells are used to inject residual brine. Since the 1980s, studies and activities have been carried out to find ways to recharge the reservoir and dispose of brine without harming the environment or underground aquifers. These include infiltration and cold-and-hot injection. Some of the studies are presented here, including analyses of litho-facies; core samples; pressure, temperature and spinner logs; well tests and injection rates-plus some studies on the shallow aquifer. All have been useful in fulfilling requirements made by environmental authorities. Because injection rates constantly decrease due to formation damage, it is proposed an additional technique be used to reduce such damages and prolong the lifetime of cold-and-hot injection wells-while ensuring the environment and shallow aquifers are not affected. [Spanish] Al igual que en diversos campos geotermicos en el mundo, en el de Cerro Prieto, Baja California se han utilizado tanto pozos inyectores perforados ex profeso como antiguos pozos exploratorios y productores para inyectar el fluido residual al subsuelo. Desde la decada de los 80 se han realizado diversos estudios y acciones en ese campo geotermico para recargar al yacimiento y para disponer del fluido residual, sin ocasionar danos al ambiente ni a los cuerpos hidricos del subsuelo, que van desde la infiltracion hasta la inyeccion en frio y en caliente. Este articulo presenta los diferentes estudios realizados con ese objetivo en el campo, incluyendo el analisis de litofacies, de nucleos de formacion, de registros de presion, temperatura y spinner, las pruebas en pozos y analisis de tasas de aceptacion, asi como los efectuados en el acuifero superficial. Todos ellos han sido de utilidad para atender los requerimientos de las autoridades ambientales. Finalmente, y en virtud de que las tasas de aceptacion de los pozos

  13. Gaseous equilibrium in sector CP IV of the Cerro Prieto, B.C. Mexico geothermal field; Equilibrio gaseoso en el sector CP IV del campo geotermico Cerro Prieto, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel; Portugal Marin, Enrique [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); De Leon Vivar, Jesus [Comision Federal de Electricidad, Campo Geotermico Cerro Prieto, Cerro Prieto, B. C. (Mexico)

    2007-07-01

    Sector CP IV is located in the NE portion of the Cerrro Prieto geothermal field. The wells of this zone produce two-phase fluids, with different characteristics as far as their steam fraction content; in the central part and towards the NW the fluids are of dominant liquid type whereas towards the E and the S, the fluid contains a relatively higher steam fraction. The results of gaseous equilibrium FT- HSH3 showed that the fluids in the deposit are at temperatures between 275 Celsius degrees and 310 Celsius degrees and contain steam fractions between 0.01 and 0.5. The data found for the natural state are aligned in a tendency defined in the diagram FT- HSH3, that suggest the wells receive different proportions from preexisting steam in the deposit, which are mixed with the liquid phase to produce the observed discharges. The present data, besides showing the presence of deposit steam, also indicates the entrance of lower temperature fluid in the central part of sector CP IV. [Spanish] El sector CP IV se localiza en la porcion NE del campo geotermico Cerro Prieto. Los pozos de esta zona producen fluidos bifasicos, con diferentes caracteristicas en cuanto a su contenido de fraccion de vapor: en la parte central y hacia el NW los fluidos son de tipo liquido dominante mientras que hacia el E y hacia el S, el fluido contiene una fraccion relativamente alta de vapor. Los resultados de equilibrio gaseoso FT-HSH3 mostraron que los fluidos en el yacimiento se encuentran a temperaturas de entre 275 grados Celsius y 310 grados Celsius y contienen fracciones de vapor de entre -.01 y .5. Los datos hallados para el estado natural se alinean en una tendencia definida en el diagrama FT-HSH3, que sugiere que los pozos reciben diferentes proporciones de vapor pre-existente en el yacimiento, que se mezclan con fase liquida para producir las descargas que se observan. Los datos actuales, ademas de mostrar la presencia de vapor de yacimiento, tambien indican la entrada de fluidos de

  14. Analysis of productive evolution of well M-19A, Cerro Prieto geothermal field, BC; Analisis de la evolucion productiva del pozo M-19A del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rodriguez, Marco H; Romero-Rios, Francisco [Comision Federal de Electricidad, Residencia General de Cerro Prieto, B.C (Mexico)]. E-mail: marco.rodriguez01@cfe.gob.mx

    2007-07-15

    Well M-19A has been the most productive in the Cerro Prieto field, producing around 40 million tons of fluid. The well went on line in February 1975 and was in continuous operation until June 2006. Monthly measurements for over 30 years of operating conditions and chemical and isotopic analyses of the fluids allow identification of the most significant processes occurring in the zone where the well is located. Three dominant recharge types have been identified, each lasting about 10 years. They are a) a recharge of fluids of lower temperature than the production fluids, even though the chemical and isotopic compositions are similar; b) a recharge of lower-temperature fluids with diluted chemical and isotopic compositions; and c) a progressive recharge of reinjected water with a higher chloride concentration and heavy isotopic composition. The production and reinjection rates for over 30 years of production history in the M-19A well zone allow for speculation of a reservoir pressure recovery, which is confirmed with a calculation using production data from well M-19A. The evolution of the reservoir pressure in the zone contrasts with the rest of the reservoir, where a constant pressure drop is observed, particularly toward the central and eastern parts of the field. [Spanish] El pozo M-19A ha sido el mas productivo del campo geotermico de Cerro Prieto, BC, alcanzando una extraccion de mas de 40 millones de toneladas de fluido. Fue integrado a produccion en febrero de 1975 y hasta junio de 2006 ha permanecido en produccion en forma continua. Las mediciones mensuales de sus condiciones operativas y los analisis quimicos e isotopicos del agua producida permiten identificar los procesos mas significativos que han ocurrido a lo largo de esos mas de 30 anos en la zona donde se localiza el pozo. Se han identificado tres tipos de recarga dominantes que se presentan durante un periodo cercano a 10 anos cada uno, los cuales son: a) una recarga de fluidos de menor temperatura

  15. Operation and Performance of a Biphase Turbine Power Plant at the Cerro Prieto Geothermal Field (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G. [Douglas Energy Company, Placentia, CA (United States)

    2000-09-01

    A full scale, wellhead Biphase turbine was manufactured and installed with the balance of plant at Well 103 of the Cerro Prieto geothermal resource in Baja, California. The Biphase turbine was first synchronized with the electrical grid of Comision Federal de Electricidad on August 20, 1997. The Biphase power plant was operated from that time until May 23, 2000, a period of 2 years and 9 months. A total of 77,549 kWh were delivered to the grid. The power plant was subsequently placed in a standby condition pending replacement of the rotor with a newly designed, higher power rotor and replacement of the bearings and seals. The maximum measured power output of the Biphase turbine, 808 kWe at 640 psig wellhead pressure, agreed closely with the predicted output, 840 kWe. When combined with the backpressure steam turbine the total output power from that flow would be increased by 40% above the power derived only from the flow by the present flash steam plant. The design relations used to predict performance and design the turbine were verified by these tests. The performance and durability of the Biphase turbine support the conclusion of the Economics and Application Report previously published, (Appendix A). The newly designed rotor (the Dual Pressure Rotor) was analyzed for the above power condition. The Dual Pressure Rotor would increase the power output to 2064 kWe by incorporating two pressure letdown stages in the Biphase rotor, eliminating the requirement for a backpressure steam turbine. The power plant availability was low due to deposition of solids from the well on the Biphase rotor and balance of plant problems. A great deal of plant down time resulted from the requirement to develop methods to handle the solids and from testing the apparatus in the Biphase turbine. Finally an online, washing method using the high pressure two-phase flow was developed which completely eliminated the solids problem. The availability of the Biphase turbine itself was 100

  16. Analysis of the automation and control of the well production conditions in the Cerro Prieto geothermal field, Mexico; Analisis de la automatizacion y del control de las condiciones de produccion de los pozos del campo geotermico de Cerro Prieto, BC, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Murillo Zamora, Isaac [Comision Federal de Electricidad, Mexicali, BC, (Mexico); Ocampo Diaz, Juan de Dios [Universidad Autonoma de Baja California, Mexicali, BC, (Mexico); De la Pena Reyna, Gilberto [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2005-12-01

    Through 31 years of development of the Cerro Prieto geothermal field, the number of wells in operation and the distances between them has been increasing. Now there are 150 wells producing a mixture of water and steam at different ratios, depending on the reservoir characteristics (pressure, temperature, depth, etc.) and the operation conditions in the superficial installations (obstructions in the orifice plates diameter, separator pressures, etc.). Therefore, Comision Federal de Electricidad (CFE) has started a pilot plan to handle the automation and control of the operating conditions of production wells, and to install a data production acquisition system. The initial results of the system are in this paper. [Spanish] A traves de los 31 anos de desarrollo del campo geotermico de Cerro Prieto el numero de pozos en operacion asi como la distancia entre ellos se ha estado incrementando. Ahora hay mas de 150 pozos produciendo una cantidad de mezcla de agua y vapor a diferentes rangos, dependiendo de las caracteristicas del yacimiento (presion, temperatura, profundidad, etc.) y de las condiciones de operacion de las instalaciones superficiales (diametros de placas de orificio obstruidos, presion de los separadores, etc.). Como resultado la Comision Federal de Electricidad (CFE) ha dado inicio a un plan de pruebas para llevar a cabo la automatizacion y control de las condiciones de operacion de los pozos productores, e instalar un sistema con equipos para recoleccion de datos del campo, cuyos primeros resultados se presentan en este articulo.

  17. Heat losses estimation associated with the physical state of the thermal insulation of pipes vaporductos network in Cerro Prieto geothermal field; Estimacion de perdidas de calor asociadas al estado fisico del aislamiento termico de las tuberias de la red de vaporductos del campo geotermico Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Martinez Estrella, Juan Ignacio; Garcia Gutierrez, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; jime@iie.org.mx; aggarcia@iie.org.mx; Canchola Felix, Ismael; Miranda Herrera, Carlos; Jacobo Galvan, Paul [Campo Geotermico de Cerro Prieto, Comision Federal de Electricidad, Mexicali, B.C. (Mexico)

    2010-11-15

    The Cerro Prieto Geothermal Field (CPGF) steam transportation network is constituted by 140 km of pipes with diameters ranging from 8 to 48 inches, which transport the steam of 165 producing wells to 13 power plants which have a total installed capacity of 720 MWe. Originally, the pipes are thermally insulated with a mineral wool or fiber glass layer and an external aluminum or iron cover. Due to the insulation material has been exposed to weather conditions during the field operation it shows nowadays different grades of wear-out, or even it is lacking in some parts of the network, causing higher heat losses from the pipes to the environment. In this work, the magnitude of the heat losses related with the present condition of the thermal insulation throughout the pipeline network is assessed. This involved determining the longitude and diameter, as well as the insulation condition of each single pipeline section, and the calculation of the heat transfer coefficients for the different thermal insulation conditions defined for this study. [Spanish] La red de transporte de vapor del campo geotermico Cerro Prieto (CGCP) esta constituida por aproximadamente 140 km de tuberias de 8 a 48 pulgadas de diametro, las cuales conducen el vapor producido por 165 pozos hacia 13 plantas generadoras, cuya capacidad instalada es de 720 MWe. Originalmente, estas tuberias son aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion exterior de aluminio o hierro. Debido principalmente al impacto de las condiciones meteorologicas durante el tiempo de operacion del campo, en algunas porciones de la red el aislante presenta actualmente distintos grados de deterioro, o incluso se encuentra ausente, lo cual se traduce en una mayor perdida de calor desde las tuberias hacia el medio ambiente. En el presente trabajo se evalua la magnitud de las perdidas de calor asociadas al estado fisico del aislamiento termico de las

  18. Determination of heat losses in the Cerro Prieto, Baja California, geothermal field steam transportation network based on the thermal insulation condition of the steam pipelines; Determinacion de perdidas de calor en la red de transporte de vapor del campo geotermico de Cerro Prieto, Baja California, con base en el estado fisico del aislamiento termico de vaporductos

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Garcia Gutierrez, Alfonso; Martinez Estrella, Juan Ignacio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; Canchola Felix, Ismael; Jacobo Galvan, Paul; Miranda Herrera, Carlos; Mora Perez, Othon [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)

    2011-07-15

    In Cerro Prieto Geothermal Field (CPGF), the steam from producing wells is transported to power plants through a large and complex system of pipes thermally insulated with a 2 inches thick mineral wool or a fiber glass layer and an external aluminum or iron cover. The insulation material has been exposed to weather conditions during the field operation and has suffered density and thickness changes. In some cases the insulation has been lost completely, increasing heat transfer from the pipes to the environment. This paper analyzes the impact of the conditions of thermal insulation on heat losses in the CPGF steam-pipeline network. The heat losses are calculated by applying an iterative method to determine the surface temperature based on a heat balance calculated from the three basic mechanisms of heat transfer: conduction, convection, and radiation. Finally, using length and diameter data corresponding to the condition of the thermal insulation of each pipeline-and field operation data, the overall heat losses are quantified for steam lines throughout the pipeline network in the field. The results allow us to evaluate the magnitude of the heat losses in comparison with the overall energy losses occurring during steam transport from wells to the power plants. [Spanish] En el Campo Geotermico de Cerro Prieto (CGCP), BC, el transporte de vapor desde los pozos hasta las plantas generadoras de electricidad se lleva a cabo mediante un extenso y complejo sistema de tuberias que tipicamente se encuentran aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion mecanica de aluminio o hierro galvanizado. Debido a la exposicion a las condiciones meteorologicas a traves del tiempo de operacion del campo, el aislamiento ha experimentado cambios en su densidad y espesor y en ocasiones se ha perdido por completo, lo cual repercute en una mayor transferencia de calor de las tuberias hacia el medio ambiente

  19. Spatio-temporal evolution of anthropogenic deformation around Cerro Prieto geothermal field in the Mexicali Valley, B.C., Mexico, between 1993 and 2009 from DInSAR and leveling.

    Science.gov (United States)

    Sarychikhina, Olga; Glowacka, Ewa; Robles, Braulio; Mojarro, Jose

    2014-05-01

    Land subsidence is an environmental hazard which could be caused by withdrawal of large amounts of fluid from beneath the earth's surface. Land subsidence is an issue in several geothermal fields worldwide (e.g., Geysers, USA (Mossop and Segall, 1997), Wairakei-Tauhara, New Zealand (Allis et al., 2009)). Cerro Prieto geothermal field (CPGF), located in the Mexicali Valley, northwest Mexico, is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field (e.g. Glowacka et al., 1996, 1999; Carnec and Fabriol, 1999; Sarychikhina et al., 2011). The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to the local infrastructure such as roads, irrigation canals and other facilities. Detection of land subsidence and monitoring of the spatial and temporal changes of its pattern and magnitude can provide important information about the dynamics of this process and controlling geological structures. The technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) has been demonstrated to be a very effective technique for measuring ground deformation. This study presents an application of DInSAR interferogram stacking technique to investigate the land subsidence in the Mexicali Valley near CPGF. C-band ENVISAR ASAR images acquired between 2003 and 2009 from the ascending (track 306, frame 639) and descending track (track 84, frame 2961), obtained from the European Space Agency (ESA), as part of ESA CAT-1 project (ID - C1P3508), were used. Gamma ISP and DIFF/GEO software packages were used to calculate differential interferograms from SLC data and for differential interferograms stacking (Wegmüller and Werner, 1997). Eight average annual deformation rate maps were generated for 2005 (descending

  20. Cerro Prieto geothermal field: exploration during exploitation

    Energy Technology Data Exchange (ETDEWEB)

    1982-07-01

    Geological investigations at Momotombo included photogeology, field mapping, binocular microscope examination of cuttings, and drillhole correlations. Among the geophysical techniques used to investigate the field sub-structure were: Schlumberger and electromagnetic soundings, dipole mapping and audio-magnetotelluric surveys, gravity and magnetic measurements, frequency domain soundings, self-potential surveys, and subsurface temperature determinations. The geochemical program analyzed the thermal fluids of the surface and in the wells. The description and results of exploration methods used during the investigative stages of the Momotombo Geothermal Field are presented. A conceptual model of the geothermal field was drawn from the information available at each exploration phase. The exploration methods have been evaluated with respect to their contributions to the understanding of the field and their utilization in planning further development.

  1. Geothermal well drilling manual at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez P., A.; Flores S., M.

    1982-08-10

    The objective of the drilling manual is to solve all problems directly related to drilling during the construction of a well. In this case, the topics dealt which are drilling fluids and hydraulics to be applied in the field to improve drilling progress, eliminate risks and achieve good well-completion. There are other topics that are applicable such as drill bits and the drilling string, which are closely linked to drilling progress. On this occasion drilling fluid and hydraulics programs are presented, in addition to a computing program for a Casio FX-502P calculator to be applied in the field to optimize hydraulics and in the analysis of hydraulics for development and exploration wells at their different intervals.

  2. Drilling rate for the Cerro Prieto stratigraphic sequence

    Energy Technology Data Exchange (ETDEWEB)

    Prian C, R.

    1981-01-01

    Drilling practice at the field has been modified in several ways as better information is being obtained. The stratigraphic sequence of the area is made up of three sedimentary rock units of deltaic origin having different densities. These units have been named non-consolidated, semi-consolidated, and consolidated rocks; the thermal reservoirs are located in the latter. To investigate how the drilling rates are affected by the three rock units, plots of drilling advance versus time were made for a large number of wells. A typical plot is shown and drilling rates are practically constant in three different zones; that is, the drilling rate has only two breaks or changes in slope.

  3. Magnetotelluric studies at the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Goubau, W.M. (Lawrence Berkeley Lab., CA); Goldstein, N.E.; Clarke, J.

    1981-01-01

    During three years of magnetotelluric surveying, data were acquired at 26 sites distributed over 190 km/sup 2/ around the production area. A relatively well-defined strike of N27W +- 1.5/sup 0/ (magnetic) was established. The simple model shown suggests a lateral discontinuity in the vicinity of Nueva Leon.

  4. The Cerro Solo Project

    International Nuclear Information System (INIS)

    The objective of the Cerro Solo Project, which was initiated in 1990, is to perform the assessment of the Co. Solo uranium ore deposit in a sequential manner. The deposit, which is located in the Patagonia Region, Argentine Republic, belongs to the sandstone type, and to the subtype coarse-grained, high energy stream. Uranium occurrences are peneconcordant, lenticular shaped and irregularly distributed in the fluvial sediments of the cretaceous Chubut Group. Resources estimated using up to present data, in tonnes of uranium recoverable at costs up to $80/kg U, are: Reasonable Assured Resources (RAR): 300 tU; Estimated Additional Resources - Category I (EAR-I): 900 tU; Estimated Additional Resources - Category II (EAR-II): 2400 tU. Resources of this ore deposit are significant to the uranium requirements in Argentina. (author). 3 refs, 6 figs

  5. Alteraciones hidrotermales superpuestas: Producto de fluidos de pH neutro y ácido en el cerro Guanaco, macizo del Deseado, Santa Cruz Superposed hydrothermal alterations: Result of neutral and acidic pH fluids in Cerro Guananco, DeseadoMassif, Santa Cruz

    Directory of Open Access Journals (Sweden)

    K. Mykietiuk

    2005-03-01

    Full Text Available Relacionadas a las mineralizaciones epitermales de metales preciosos de la zona Cerro Guanaco, macizo del Deseado, se reconocieron alteraciones producidas por fluidos de pH neutro sobre las que se sobrepuso una alteración producto de fluidos de pH ácido. Los fluidos de pH neutro generaron una alteración argílica caracterizada principalmente por illita con algunos interestratificados de illita-montmorillonita y una propilítica con epidoto, calcita y clorita. Los fluidos de pH ácido generaron una zona de cuarzo poroso y una alteración argílica avanzada con la asociación mineralógica de diásporo, pirofilita, dickita, illita, illita-montmorillonita, caolinita y cuarzo. Teniendo en cuenta la morfología mantiforme de los cuerpos alterados por aguas ácidas junto con sus relaciones de corte con las alteraciones producto de aguas neutras, es posible interpretar a la alteración argílica avanzada como resultado de la circulación de aguas ácidas calentadas por vapor. La presencia de minerales que indican temperaturas del orden de los 250°C se atribuye a una actividad magmática tardía en el área.Epithermal precious metal mineralization is well developed in the Cerro Guanaco area, Deseado Massif. Two different suites of alteration have been recognized, one product of neutral fluids and the other of acid fluids. The neutral suite is characterized by the presence of argillic and propillitic alteration; while the acid suite is formed by advanced argillic alteration with diaspore, pyrophyllite, dickite, illite, illite-montmorillonite and quartz. Coupled with the evidence for the relatively shallow level of erosion in the area, and the alteration body of these zones of advanced argillic alteration, there is a relationship to steam-heated fluids descending fractures below a perched water table.

  6. Proceedings: third symposium on the Cerro Prieto geothermal field, Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    These proceedings include both English and Spanish versions of each paper presented at the symposium. Illustrations and tables, which have been placed between the two versions, include captions in both languages. Forty-one papers are included. Five papers were indexed for EDB previously. Separate abstracts were prepared for thirty-three papers and three were listed by title.

  7. Analysis of exploratory wells in the Cerro Prieto Field and the Mexicali Valley

    Energy Technology Data Exchange (ETDEWEB)

    Cobo R., J.M.; Bermejo M., F.J.

    1982-08-10

    Agricultural development in the Mexicali Valley and in the high cost of electric power required to operate the irrigation wells in the Valley prompted the Mexican government to investigate the possibility of taking advantage of thermal manifestations in the area located 28 km southeast of the city of Mexicali to generate electric power and thereby partially decrease the flight of foreign exchange. In 1958, a geologic study of the southern and southeastern zone of Mexicali was conducted to identify the possibilities of tapping geothermal resources. The purpose of this study was to gain knowledge of the geologic conditions in this area and, if possible, to establish the location of exploratory and production wells and, on the basis of the results of the former, examine the geologic history in order to gain knowledge and understanding of the structural control of the steam. On the basis of this study, it was recommended that 3 exploratory wells should be drilled in order to locate weak zones that would easily allow for steam flow.

  8. Pressure changes and their effects on the Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Bermejo M, F.J.; Navarro O, F.X.; Esquer P, C.A.; Castillo B, F.; de la Cruz D, F.C.

    1981-01-01

    Continuous extraction of the water-steam mixture at the field has been increasing to fulfill the steam requirements of the power plant. As a result, pressure declines have been observed in the producing strata in all of the wells, as well as in the geothermal reservoir as a whole. Anomalous behavior that has been observed in the wells' hydraulic columns in most cases is due to the interconnection of the various strata penetrated by the well. When this occurs, unbalanced hydraulic pressures cause the movement of fluids between the strata. As an example of this hydraulic imbalance causing the flow of fluids from an upper to a lower zone, well Nuevo Leon 1 where this effect occurs between regions 600 m apart was chosen.

  9. Treatment of the Cerro Prieto I brines for use in reinjection. 2. Results of the pilot plant tests

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado J, R. (Instituto de Investigaciones Electricas, Mexicali, Mexico); Mercado G, S.; Rocha C, E.; Gamino O, H.; Garibaldi P, F.

    1981-01-01

    Silica removal experiments have been carried out both in the laboratory and in pilot scale tests. The results obtained to date are presented, with special emphasis on the pilot tests with or without the use of flocculants. Previous studies on brine treatment are described briefly.

  10. Sedimentary rocks Uranium in Cerro Largo Province

    International Nuclear Information System (INIS)

    With the aim of the uranium minerals exploration has been carried out several studies by UTE technicians in Cerro Largo Province from 1968 to 1969. In uranium concentration has been found pyrite, phosphate, iron oxides and manganese in uranium. Furthermore in La Divisa Ore were studied concentration Uranium enrichment has been studied in La Divisa ore

  11. Accurate Geodetic Coordinates for Observatories on Cerro Tololo and Cerro Pachon

    CERN Document Server

    Mamajek, Eric E

    2012-01-01

    As the 50th anniversary of the Cerro Tololo Inter-American Observatory (CTIO) draws near, the author was surprised to learn that the published latitude and longitude for CTIO in the Astronomical Almanac and iraf observatory database appears to differ from modern GPS-measured geodetic positions by nearly a kilometer. Surely, the position for CTIO could not be in error after five decades? The source of the discrepancy appears to be due to the ~30" difference between the astronomical and geodetic positions -- a systematic effect due to vertical deflection first reported by Harrington, Mintz Blanco, & Blanco (1972). Since the astronomical position is not necessarily the desired quantity for some calculations, and since the number of facilities on Cerro Tololo and neighboring Cerro Pachon has grown considerably over the years, I decided to measure accurate geodetic positions for all of the observatories and some select landmarks on the two peaks using GPS and Google Earth. Both sets of measurements were inter-...

  12. Photosynthesis within Mars' volcanic craters?: Insights from Cerro Negro Volcano, Nicaragua

    Science.gov (United States)

    Rogers, K. L.; Hynek, B. M.; McCollom, T. M.

    2011-12-01

    Discrete locales of sulfate-rich bedrocks exist on Mars and in many cases represent the products of acid-sulfate alteration of martian basalt. In some places, the products have been attributed to hydrothermal processes from local volcanism. In order to evaluate the habitability of such an environment, we are investigating the geochemical and biological composition of active fumaroles at Cerro Negro Volcano, Nicaragua, where fresh basaltic cinders similar in composition to martian basalts are altered by acidic, sulfur-bearing gases. Temperatures at active fumaroles can reach as high as 400°C and the pH of the steam ranges from red algae that inhabit acidic, geothermal environments. Many of sequences related to Ktedonobacteria and Actinobacteria have also been found in acid mine drainage environments. The Archaeal community was far less diverse, with sequences matching those of unclassified Desulfurococcales and unclassified Thermoprotei. These sequences were more distant from isolated species than the bacterial sequences. Similar bacterial and archaeal communities have been found in hot spring environments in Yellowstone National Park, Greenland, Iceland, New Zealand and Costa Rica. Some of Mars' volcanoes were active for billions of years and by analogy to Cerro Negro, may have hosted photosynthetic organisms that could have been preserved in alteration mineral assemblages. Even on a generally cold and dry Mars, volcanic craters likely provided long-lived warm and wet conditions and should be a key target for future exploration assessing habitability.

  13. Accurate Geodetic Coordinates for Observatories on Cerro Tololo and Cerro Pachon

    OpenAIRE

    Mamajek, Eric E.

    2012-01-01

    As the 50th anniversary of the Cerro Tololo Inter-American Observatory (CTIO) draws near, the author was surprised to learn that the published latitude and longitude for CTIO in the Astronomical Almanac and iraf observatory database appears to differ from modern GPS-measured geodetic positions by nearly a kilometer. Surely, the position for CTIO could not be in error after five decades? The source of the discrepancy appears to be due to the ~30" difference between the astronomical and geodeti...

  14. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    ridge system, sulfide minerals crystallize from the hot water directly onto the volcanic rocks surrounding the hydrothermal vent leading to the formation of hollow, chimney like sulfide structure through which the hot water continues to flow... systems, which are in turn an integral component of global mid-ocean ridge system. Hydrothermal systems are composed of convection cells in the crust and upper mantle through which seawater freely circulates reacting with magmatic material, which...

  15. Optical atmospheric extinction over Cerro Paranal

    CERN Document Server

    Patat, F; O'Brien, K; Pompei, E; Bensby, T; Carraro, G; Postigo, A de Ugarte; Fox, A; Gavignaud, I; James, G; Korhonen, H; Ledoux, C; Randall, S; Sana, H; Smoker, J; Stefl, S; Szeifert, T

    2010-01-01

    Aims: The present study was conducted to determine the optical extinction curve for Cerro Paranal under typical clear-sky observing conditions, with an accuracy of 0.01 mag/airmass. Methods: The extinction curve of Paranal was obtained through low-resolution spectroscopy of 8 spectrophotometric standard stars observed with FORS1 mounted at the 8.2 m Very Large Telescope, covering a spectral range 3300-8000 A. A total of 600 spectra were collected on more than 40 nights distributed over six months, from October 2008 to March 2009. The average extinction curve was derived using a global fit algorithm, which allowed us to simultaneously combine all the available data. The main atmospheric parameters were retrieved using the LBLRTM radiative transfer code, which was also utilised to study the impact of variability of the main molecular bands of O2, O3, and H2O, and to estimate their column densities. Results: In general, the extinction curve of Paranal appears to conform to those derived for other astronomical si...

  16. Herpetofauna del Cerro Guiengola, Istmo de Tehuantepec, Oaxaca

    OpenAIRE

    Cintia Natalia Martín-Regalado; Rosa Ma. Gómez-Ugalde; Ma. Emma Cisneros-Palacios

    2011-01-01

    Este estudio se realizó en el Cerro Guiengola, Tehuantepec, Oaxaca, con el objetivo de contribuir al conocimiento de la herpetofauna en dicha área. Se obtuvieron 602 registros visuales y se recolectaron 103 ejemplares de anfibios y reptiles durante 60 días de trabajo de campo. Se enlistan 40 especies, pertenecientes a 33 géneros y 18 familias. Se determinó la distribución de la herpetofauna en el Cerro Guiengola por microhábitat, tipo de vegetación y altitud. Usando el método de Jaccard se el...

  17. Report of boring made in the South of Cerro Largo district (Cerro Largo) 1977-1978

    International Nuclear Information System (INIS)

    The present work are within the framework and compiles the data obtained by means of the study of the perforations executed in the District Cerro Largo Sur of the detailed prospection of uranium minerals. This study was carried out by technicians of Geologic ex--Institute of Uruguay (IGU) - at the moment National Direction of Mining and Geology. (DINAMIGE). The works began at the beginning of 1977 and continued until 1978 July; The headquarters of the program of prospection of uranium was carried out by Ing. Hector Goso. In this report the conclusions drawn at the time of the detection of the works in the District already published, as well as the litologicos cuts of all the executed perforations are included

  18. EL CERRO DE POTOSÍ Y EL DIOS PACHACÁMAC THE CERRO DE POTOSÍ AND THE PACHACÁMAC GOD

    OpenAIRE

    Teresa Gisbert

    2010-01-01

    En este trabajo se plantea que el Cerro de Potosí se ocultó a los españoles por ser el santuario más importante de la región, el cual estaba dedicado al dios Pachacámac. Los testimonios que indican que el cerro de Potosí era "Apu" (Cerro o Señor) adorado son abundantes, pero es el cronista Arzans de Orsúa y Vela (año 1736) quien dice que este "Apu" pertenecía a Pachacámac, dios del mundo subterráneo. Una tradición recogida cerca del salar de Uyuni dice lo mismo; finalmente un sacrificio reali...

  19. EL CERRO DE POTOSÍ Y EL DIOS PACHACÁMAC THE CERRO DE POTOSÍ AND THE PACHACÁMAC GOD

    Directory of Open Access Journals (Sweden)

    Teresa Gisbert

    2010-06-01

    Full Text Available En este trabajo se plantea que el Cerro de Potosí se ocultó a los españoles por ser el santuario más importante de la región, el cual estaba dedicado al dios Pachacámac. Los testimonios que indican que el cerro de Potosí era "Apu" (Cerro o Señor adorado son abundantes, pero es el cronista Arzans de Orsúa y Vela (año 1736 quien dice que este "Apu" pertenecía a Pachacámac, dios del mundo subterráneo. Una tradición recogida cerca del salar de Uyuni dice lo mismo; finalmente un sacrificio realizado en el siglo XVI a orillas del lago Titicaca en honor a Pachacámac, muestra la presencia de este dios en el Collasuyo. Cuando los incas llegaron a Potosí introdujeron el culto al Sol y cuando llegaron los españoles identificaron el cerro con la Virgen María la cual, a su vez, se identificó con la Pachamama o Madre Tierra.In this essay it is argued that "Cerro de Potosf' was hidden from the Spanish conquerors because it was the region's most important huaca or sanctuary, due to the fact that it was dedicated to the god Pachacámac. Abundant testimonies (colonial documents indicate that "Cerro de Potosf was a worshipped "Apu" (Mountain, Señor or Lord, nevertheless chronicler Orzans de Orsúa y Vela (1736 stated that this "Apu" belonged to Pachacámac, god of the underworld. A tradition collected near the Salar de Uyuni states the same; finally, a sacrifice in honor of Pachacámac that occurred during the 16th century on the shores of Lake Titicaca, shows the presence of this god in the Collasuyo. When the Incas reached Potosí, they introduced worship of the Sun, and when the Spanish conquerors arrived, they identified the "Cerro de Potosf with the Virgin Mary which at the same time was identified with Pachamama or Mother Earth.

  20. The Cerro LOS Calvos and La Banderia chondrites

    Science.gov (United States)

    Whitlock, Randall; Lewis, Charles F.; Clark, James C.; Moore, Carleton B.

    1991-06-01

    The Cerro los Calvos meteorite is a single stone of 68.5 g found in the Nuevo Mercurio strewn field of Zacatecas, (Mexico). It is an unusual H4 chondrite. Its olivine (Fa12.5) and orthopyroxene (Fs 11.7, Wo 0.8) are reduced relative to typical H chondrites. The La Banderia meteorite of 54.3 g from the same vicinity is an LL5 chondrite of shock classification e.

  1. Atmospheric conditions at Cerro Armazones derived from astronomical data

    Science.gov (United States)

    Lakićević, Maša; Kimeswenger, Stefan; Noll, Stefan; Kausch, Wolfgang; Unterguggenberger, Stefanie; Kerber, Florian

    2016-04-01

    Aims: We studied the precipitable water vapour (PWV) content near Cerro Armazones and discuss the potential use of our technique of modelling the telluric absorbtion lines for the investigation of other molecular layers. The site is designated for the European Extremely Large Telescope (E-ELT) and the nearby planned site for the Čerenkov Telescope Array (CTA). Methods: Spectroscopic data from the Bochum Echelle Spectroscopic Observer (BESO) instrument were investigated by using a line-by-line radiative transfer model (LBLRTM) for the Earth's atmosphere with the telluric absorption correction tool molecfit. All observations from the archive in the period from December 2008 to the end of 2014 were investigated. The dataset completely covers the El Niño event registered in the period 2009-2010. Models of the 3D Global Data Assimilation System (GDAS) were used for further comparison. Moreover, we present a direct comparison for those days for which data from a similar study with VLT/X-Shooter and microwave radiometer LHATPRO at Cerro Paranal are available. Results: This analysis shows that the site has systematically lower PWV values, even after accounting for the decrease in PWV expected from the higher altitude of the site with respect to Cerro Paranal, using the average atmosphere found with radiosondes. We found that GDAS data are not a suitable basis for predicting local atmospheric conditions - they usually systematically overestimate the PWV values. The large sample furthermore enabled us to characterize the site with respect to symmetry across the sky and variation with the years and within the seasons. This technique of studying the atmospheric conditions is shown to be a promising step into a possible monitoring equipment for the CTA. Based on archival observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile and of the Cerro Armazones Observatory facilities of the Ruhr Universität Bochum.Full Table 1

  2. Report of the Cerro Chato ultrabasic geophysical studies

    International Nuclear Information System (INIS)

    This report refers to the obtained results of geophysical practiced during the year 1985 in the area of the ultrabasic of Cerro Chato, located in the area called Puntas del Malbajar in Durazno province. The aim was rehearsed an answer of an ultrabasic behaviour of the geophysical prospecting methods.They were carried out studies in magnetometry, induced polarization, electromagnetism and resistivity measurements in electric vertical sound. As well conclusions as recommendations express that applied geophysical methods allow to make ultrabasic charts or maps.

  3. Characterization of pottery from Cerro de Las Ventanas, Zacatecas, Mexico

    International Nuclear Information System (INIS)

    With the aim of classifying prehispanic pottery from Cerro de Las Ventanas site, Juchipila, Zacatecas, Mexico, instrumental neutron activation analysis (INAA) was used to analyze ceramic samples at the University of Missouri Research Reactor Center. Thirty-two chemical elements were measured: Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Ti, Th, U, V, Yb, Zn, and Zr. Two multivariate statistical methods, cluster analysis and principal component analysis, were performed on the dataset to examine similarities between samples and to establish compositional groups. The statistical analyses of the dataset suggest that the pottery samples form a unique chemically homogeneous group, with the exception of one pottery sample. The compositional data were compared to an existing Mesoamerican ceramic database. It was found that the newly generated data fit best with data from a previous chemical analysis of pottery from the Malpaso Valley. However, despite the apparent similarity, pottery samples from the site of Cerro de Las Ventanas represent a new and unique chemical fingerprint in the region. (orig.)

  4. Characterization of pottery from Cerro de Las Ventanas, Zacatecas, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-del-Rio, H.; Mireles-Garcia, F. [Unidad Academica de Estudios Nucleares, UAZ, Zacatecas (Mexico); Mendez-Cardona, R.Y. [Unidad Academica de Antropologia, UAZ, Zacatecas (Mexico); Nicolas-Caretta, M. [INAH Delegacion Zacatecas (Mexico); Coordinacion de Ciencias Sociales y Humanidades, UASLP, Fracc. Talleres, SLP (Mexico); Speakman, R.J. [Museum Conservation Inst., Smithsonian Institution, Suitland, MD (United States); Glascock, M.D. [Research Reactor Center, Univ. of Missouri, Columbia, MO (United States)

    2009-09-15

    With the aim of classifying prehispanic pottery from Cerro de Las Ventanas site, Juchipila, Zacatecas, Mexico, instrumental neutron activation analysis (INAA) was used to analyze ceramic samples at the University of Missouri Research Reactor Center. Thirty-two chemical elements were measured: Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Ti, Th, U, V, Yb, Zn, and Zr. Two multivariate statistical methods, cluster analysis and principal component analysis, were performed on the dataset to examine similarities between samples and to establish compositional groups. The statistical analyses of the dataset suggest that the pottery samples form a unique chemically homogeneous group, with the exception of one pottery sample. The compositional data were compared to an existing Mesoamerican ceramic database. It was found that the newly generated data fit best with data from a previous chemical analysis of pottery from the Malpaso Valley. However, despite the apparent similarity, pottery samples from the site of Cerro de Las Ventanas represent a new and unique chemical fingerprint in the region. (orig.)

  5. Fluid evolution of Cerro Colorado Porphyry Copper Mine

    Science.gov (United States)

    Tsang, Debbie Pui Wai; Wallis, Simon

    2014-05-01

    The Cerro Colorado porphyry copper deposit is the northernmost currently active copper mine in Chile, producing 90.5kt copper per year. It belongs to one of the Paleocene to early Eocene porphyry copper deposits that are distributed along the western slope of the main Andean Cordillera in Northern Chile (Bouzari & Clark, 2002). Active commercial production began in 1994, and the estimated reserves within the supergene blanket can sustain further 12 years of copper mining. Field studies of the well-exposed geology around the mine site and the access to drilled cores that penetrate into the hypogene zone provide a good opportunity to study the temporal relationship between magmatism, hypogene and supergene ore formation of the region. The geological evolution of Cerro Colorado area can be generalized as follows. The Cretaceous Cerro Empexa Formation, consisting of a sequence of volcanic rocks, mainly andesitic lava and breccia, lahars, some ignimbrite intercalations and dacitic tuff (Charrier, Pinto & Rodrigues, 2007), was intruded by tonalitic to dioritic magma in Middle-Eocene. Magmatic activities generated brecciated rocks accompanying with different alteration zones radiate outward from the intrusion. The mineralized hypogene protore later interacted with ground water, creating the supergene blanket, which is now the principal mining target of Cerro Colorado. Several plutonic lithologies with slight but distinct compositional differences were exposed in the valleys around the mine site. The presence of these several phases of small-scale intrusions suggests the ore genesis may be related to multiple pulses of heating and associated fluid flow. Complementarily, on-site geologists have reported occurrences of early stage biotites vein cutting into phyllitic alteration zone, or across terminal stage quartz-pyrite veins in the drilled cores. These observations are direct evidences of at least two major distinct phases of fluid flow, and imply the ore mineralization

  6. Report of mortmorilloniticas clay in the Medina swamp (Cerro Largo district)

    International Nuclear Information System (INIS)

    This report describes the prospect ion work for the montmorillonitics clay in the region of Medina swamp in Cerro Largo district. The existence of new deposits was detected by cartography and geological study.

  7. Hidrogeologic and geophysical studies into Agro school Melo UTU Cerro Largo province

    International Nuclear Information System (INIS)

    The technical University UTU of Uruguay requested and Hidrogeologic study with the aim to analyze the factibility to discover underground stream waters which supply groundwaters into agro school Ing Agr. Alcides E Pintos Melo, Cerro Largo province.

  8. Evaluation of the physical characteristic of Cerro bend blocks used for radiation therapy

    International Nuclear Information System (INIS)

    In Radiation Therapy, the sparing of normal tissues can be performed using either multi-leaf collimators or Cerro bend blocks. The current work focuses on the physical characteristics of Cerro bend blocks including attenuation coefficient, effective penumbra width and isodose curves undulation in penumbral regions. Materials and Methods: All measurements were performed using a dual energy linac and the Cerro bend blocks designed and fabricated using a commercial Cerro bend material. Data were collected using a calibrated ionization chamber as well as EDR2 films. Results: The results showed that the attenuation coefficient was found to be 0.4475 and 0.4276 cm-1 for photon beams 6 MV and 15 MV, respectively, and a potential air bubble with a diameter greater than 3 mm affects beam attenuation significantly. The optimum Cerro bend block width was found to be around 16 mm. The isodose curves scalloping achieved for secondary collimator jaws, were also similar. Conclusion: If Cerro bend blocks are used as a basic method to protect normal tissues, its physical characteristics will be recommended to be taken into account comprehensively.

  9. Uranium and Molybdenum extraction from a Cerro Solo deposit ore

    International Nuclear Information System (INIS)

    Cerro Solo, located in Chubut, Argentina, is a sandstone type uranium-molybdenum deposit. Good recovery of both elements can be achieved by acid leaching of the ore but the presence of molybdenum in pregnant liquors is an inconvenient to uranium separation and purification. A two steps process is developed. A selective alkaline leaching of the ore with sodium hydroxide allows separating and recovering of molybdenum and after solid-liquid separation, the ore is acid leached to recover uranium. Several samples averaging 0,2% uranium and 0,1% molybdenum with variable U/Mo ratio have been used and in both steps, leaching and oxidant reagents concentration, temperature and residence time in a stirred tank leaching have been studied. In alkaline leaching molybdenum recoveries greater than 96% are achieved, with 1% uranium extraction. In acid leaching up to 93% of the uranium is extracted and Mo/U ratio in solvent extraction feed is between 0,013 and 0,025. (author)

  10. Uranium hydrothermal deposits

    Czech Academy of Sciences Publication Activity Database

    René, Miloš

    New York : Nova Science Publishers, 2012 - (Vasiliev, A.; Sidorov, M.), s. 211-244 ISBN 978-1-62081-207-5 Institutional research plan: CEZ:AV0Z30460519 Keywords : uranium * hydrothermal deposits * uraninite Subject RIV: DB - Geology ; Mineralogy

  11. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Rudolf, Andreas

    2011-01-01

    dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction. In......This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During the...... hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed by...

  12. The age and constitution of Cerro Campanario, a mafic stratovolcano in the Andes of Central Chile

    OpenAIRE

    Wes Hildreth; Brad Singer; Estanislao Godoy; Francisco Munizaga

    1998-01-01

    ABSTRACT Cerro Campanario, a towering landmark on the continental divide near Paso Pehuenche, is a glacially eroded remnant of a mafic stratovolcano that is much younger than previously supposed. Consisting of fairly uniform basaltic andesite, rich in olivine and plagioclase, the 10-15 km³ edifice grew rapidly near the end of the middle Pleistocene, about 150-160 ka, as indicated by 40Ar/39Ar and unspiked K-Ar analyses of its lavas.La edad y formación del cerro Campanario, un estratovolcán má...

  13. Catalytic Hydrothermal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2015-05-31

    The term “hydrothermal” used here refers to the processing of biomass in water slurries at elevated temperature and pressure to facilitate the chemical conversion of the organic structures in biomass into useful fuels. The process is meant to provide a means for treating wet biomass materials without drying and to access ionic reaction conditions by maintaining a liquid water processing medium. Typical hydrothermal processing conditions are 523-647K of temperature and operating pressures from 4-22 MPa of pressure. The temperature is sufficient to initiate pyrolytic mechanisms in the biopolymers while the pressure is sufficient to maintain a liquid water processing phase. Hydrothermal gasification is accomplished at the upper end of the process temperature range. It can be considered an extension of the hydrothermal liquefaction mechanisms that begin at the lowest hydrothermal conditions with subsequent decomposition of biopolymer fragments formed in liquefaction to smaller molecules and eventually to gas. Typically, hydrothermal gasification requires an active catalyst to accomplish reasonable rates of gas formation from biomass.

  14. Evaluation of the Cerro Solo nuclear ore, province of Chubut. The Cerro Solo project within the frame of uranium exploration in Argentina. Pt. 1

    International Nuclear Information System (INIS)

    The Cerro Solo ore deposit was selected by the CNEA to invest in an assessment project because of their promising grade and amount of known and potential resources, significant to Argentina's uranium requirements. The deposit, which is located in the central region of the Chubut Province, belongs to the sandstone type and is hosted by the cretaceous Chubut Group. Technical studies carried out forecast an important growth of nuclear capacity to meet Argentina's energy requirements in the first two decades of of the the next century. To be in position to confront the challenge presented by increasing uranium resources to fuel the nuclear powers plants it is very important, as a first step, to improve the geological knowledge of uranium favorability in the country. The preliminary results of the Cerro Solo project indicate that the eastern slope of the Pichinan hills is a promising area for development of uranium resources, increasing the favorability of the San Jorge Basin in order to allow contributing to meet future uranium requirements. The Cerro Solo Project was planned in a sequential manner, as a multidisciplinary effort which includes studies on: geologic setting of mineralization, resource estimates, costs of mining and milling methods, economic analysis and environmental impact research. Among the mining methods, studies include the alternative of the in-situ leaching technology, which is becoming a low producing cost interesting possibility. (Author)

  15. The Marianas-San Marcos vein system: characteristics of a shallow low sulfidation epithermal Au-Ag deposit in the Cerro Negro district, Deseado Massif, Patagonia, Argentina

    Science.gov (United States)

    Vidal, Conrado Permuy; Guido, Diego M.; Jovic, Sebastián M.; Bodnar, Robert J.; Moncada, Daniel; Melgarejo, Joan Carles; Hames, Willis

    2016-08-01

    The Cerro Negro district, within the Argentinian Deseado Massif province, has become one of the most significant recent epithermal discoveries, with estimated reserves plus resources of ˜6.7 Moz Au equivalent. The Marianas-San Marcos vein system contains about 70 % of the Au-Ag resources in the district. Mineralization consists of Upper Jurassic (155 Ma) epithermal Au- and Ag-rich veins of low to intermediate sulfidation style, hosted in and genetically related to Jurassic intermediate composition volcanic rocks (159-156 Ma). Veins have a complex infill history, represented by ten stages with clear crosscutting relationships that can be summarized in four main episodes: a low volume, metal-rich initial episode (E1), an extended banded quartz episode with minor mineralization (E2), a barren waning stage episode (E3), and a silver-rich late tectonic-hydrothermal episode (E4). The first three episodes are interpreted to have formed at the same time and probably from fluids of similar composition: a 290-230 °C fluid dominated by meteoric and volcanic waters (-3‰ to -0‰ δ18Owater), with precipitated at the beginning of vein formation (episode 1) due to a combination of boiling at ˜600 to 800 m below the paleowater table, and associated mixing/cooling processes, as evidenced by sulfide-rich bands showing crustiform-colloform quartz, adularia, and chlorite-smectite banding. During episodes 2 and 3, metal contents progressively decrease during continuing boiling conditions, and veins were filled by quartz and calcite during waning stages of the hydrothermal system, and the influx of bicarbonate waters (-6 to -8.5 ‰ δ18Owater). Hydrothermal alteration is characterized by proximal illite, adularia, and silica zone with chlorite and minor epidote, intermediate interlayered illite-smectite and a distal chlorite halo. This assemblage is in agreement with measured fluid inclusion temperatures. A striking aspect of the Marianas-San Marcos vein system is that the high

  16. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  17. Forecast of environmental impact in the evaluation of Cerro Solo nuclear mine

    International Nuclear Information System (INIS)

    This work presents a project for the study of the environmental impact of the Cerro Solo uranium mine. The survey is to be carried out performing different kinds of studies: mineralization, tectonics, hydrogeology, preliminary studies on different exploitation methods, costs, reserves estimation, economical studies and preliminary studies on possible environmental impacts. (author). 24 refs., 1 fig., 1 tab

  18. Hydrothermal conversion of biomass

    NARCIS (Netherlands)

    Knezevic, Dragan

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of wat

  19. Eruptive Variations During the Emplacement of Cerro Pinto, an Ambitious Rhyolite Dome, Puebla, Mexico

    Science.gov (United States)

    Zimmer, B.; Riggs, N.; Carrasco-Nunez, G.

    2006-12-01

    Cerro Pinto is a rhyolite dome complex located in the eastern Trans-Mexican Volcanic Belt. The complex is composed of four tuff rings and four domes that were emplaced in three distinct eruptive stages marked by changes in vent location and eruptive character. Each of these stages contained eruptive sequences that follow simple rhyolite-dome models, in which a pyroclastic phase is followed immediately by effusive dome emplacement. However, some aspects of the eruptive history, such as the occurrence of explosive reactivation and dome destruction through a lateral blast are uncommon in small rhyolitic structures and are more commonly associated with polygenetic structures, such as stratovolcanoes or calderas. In these larger structures, new pulses of magma often initiate reactivation, but at Cerro Pinto the story is different. Major and trace element geochemistry suggest that Cerro Pinto was sourced by a small, isolated magma chamber, unassociated with any surrounding silicic centers and did not experience any change in chemical composition over the course of the eruption. Based on these data and field observations, it is inferred that Cerro Pinto's eruptive variations were not the result of the influx of a new magma batch, but were the result of both phreatomagmatic interactions and the presence of a small magma chamber that was zoned with respect to volatiles. Both of these factors are commonly encountered in volcanologic studies, but documentation of their influence on smaller structures is under represented. Rhyolite domes have long been considered relatively simple volcanic structures with only localized hazard implications. However, the eruptive variations displayed by Cerro Pinto suggest that isolated rhyolite dome evolutions can be much more complex with the potential for explosive reactivation and dome collapse; events that must be taken into consideration when making hazard assessments.

  20. Evolución petrotectónica del distrito minero Cerro Áspero y modelo de emplazamiento de los depósitos wolframíferos, Córdoba Petrotectonic evolution of the Cerro Aspero mining district and emplacement model of the wolframiferous deposits, Córdoba

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2005-03-01

    located in the eastern part of the Sierra de Comechingones. The region was affected by polimetamorphism during the Pampean and Famatinian cycles. At least two events of simple shearing (D3 and D4 and penetrative structures (S2, S3 and S4 were developed, favouring the anorogenic intrusion of Cerro Aspero batholith since late Devonian. This magmatic event was followed by a reactivation of deformation structures and circulation of hydrothermal fluids through rocks underlying a massive amphibolite level belonging to La Aguada formation, which mainly acted as an impermeable barrier in the area. A maximum stress s1 directed 330º promoted the development of mineralized systems following the fracturing pattern of Riedel's model, and also the development of a principal mineralized path related to a simple dextral shear belt, 285º in direction (S5. During the evolution of the magmatic-hydrothermal system, a high number of stages of fracturing and opening along rocks were registered, with sealing of cavities by mechanism of crack seal and pressure dissolution. By these mechanisms, fibrous habit silica was precipitated and metallic elements were concentrated, under a traction regime and a pore fluid pressure estimated in 195 MPa. The age of one of the mineralizing stages was determined in 343,8 ± 10,8 Ma through K/Ar dating in muscovite.

  1. Consideration of the ultramafic intrusive rocks in Arroyo Las Palmas (ex Cerro Chato - Las Canias) Durazno. R. O. del Uruguay

    International Nuclear Information System (INIS)

    This work is about the ultramafic rocks which its chemistry composition fluctuate since the basic to the ultra basic field and appear in the nascent of the Las Palmas stream near Las Canias and Cerro Chato district.

  2. Hydrothermal synthesis of hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Earl, J S; Wood, D J; Milne, S J [Institute for Materials Research, University of Leeds, Leeds, LS2 9JT (United Kingdom)

    2006-02-22

    A hydrothermal method of synthesizing hydroxyapatite by heating a precipitate, formed by mixing Ca(NO{sub 3}){sub 2}{center_dot}4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4} with distilled water, in a hydrothermal reactor at 200 deg. C for 24-72 hrs is described. A treatment time of 24 hrs produced single phase (as shown by XRD) hydroxyapatite powder, however for longer treatment times XRD patterns were indicative of the presence of a secondary phase, monetite (CaHPO{sub 4}). SEM examination of the treated powders displayed particles of rod-like morphology with dimensions 100-500 nm in length and 10-60 nm in diameter. Preliminary results on the use of the particles for the infiltration of dentine tubules are presented.

  3. Hydrothermal conversion of biomass

    OpenAIRE

    Knezevic, Dragan

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of water and high energy consumption that it requires can be avoided. The main focus of this work was HTC process aiming at production of transportation fuel intermediates. For this study, a new experime...

  4. New mammalian records in the Parque Nacional Cerros de Amotape, northwestern Peru

    OpenAIRE

    Cindy M. Hurtado; Víctor Pacheco

    2015-01-01

    The Pacific Tropical Rainforest and Equatorial Dry Forest are found only in southern Ecuador and northern Peru, and are among the most poorly known ecosystems of South America. Even though these forests are protected in Parque Nacional Cerros de Amotape (PNCA), they are threatened by fragmentation because of farming and agriculture. The aim of this study was to determine the medium and large mammalian species richness, using transect census, camera trapping, and specimen bone collection. Nine...

  5. Study of the atmospheric conditions at Cerro Armazones using astronomical data

    OpenAIRE

    Lakicevic, Masha; Kimeswenger, Stefan; Noll, Stefan; Kausch, Wolfgang; Unterguggenberger, Stefanie; Kerber, Florian

    2016-01-01

    Aims: We studied the precipitable water vapour (PWV) content near Cerro Armazones and discuss the potential use of our technique of modelling the telluric absorbtion lines for the investigation of other molecular layers. The site is designated for the European Extremely Large Telescope (E-ELT) and the nearby planned site for the Cherenkov Telescope Array (CTA). Methods: Spectroscopic data from the Bochum Echelle Spectroscopic Observer (BESO) instrument were investigated by using line-by-line ...

  6. The age and constitution of Cerro Campanario, a mafic stratovolcano in the Andes of central Chile

    Science.gov (United States)

    Hildreth, W.; Singer, B.; Godoy, E.; Munizaga, F.

    1998-01-01

    Cerro Campanario, a towering landmark on the continental divide near Paso Pehuenche, is a glacially eroded remnant of a mafic stratovolcano that is much younger than previously supposed. Consisting of fairly uniform basaltic andesite, rich in olivine and plagioclase, the 10-15 km3 edifice grew rapidly near the end of the middle Pleistocene, about 150-160 ka, as indicated by 40Ar/39Ar and unspiked K-Ar analyses of its lavas.

  7. El bronce final y la Edad del Hierro en "Cerro del Berrueco" (Ávila-Salamanca

    Directory of Open Access Journals (Sweden)

    J. Francisco FABIÁN GARCÍA

    2009-10-01

    Full Text Available El Cerro del Berrueco es un monte-isla enclavado en las inmediaciones del Sistema Central y, más concretamente, de las Sierras de Gredos y Béjar, en el sector Sur-Occidental de la Meseta Norte. Corresponde una parte de él a la provincia de Avila y otra, más extensa, a la de Salamanca.

  8. Light pollution at high zenith angles, as measured at Cerro Tololo Inter-American Observatory

    CERN Document Server

    Krisciunas, Kevin; Sanhueza, Pedro; Smith, Malcolm G

    2010-01-01

    On the basis of measurements of the V-band sky brightness obtained at Cerro Tololo Inter-American Observatory in December 2006 and December 2008 we confirm the functional form of the basic model of Garstang (1989, 1991). At high zenith angles we measure an enhancement of a factor of two over Garstang's later model when there is no marine cloud layer over La Serena/Coquimbo. No corresponding enhancement is found in the B-band.

  9. Works carried out in the south of Cerro Largo district. Uranium prospection programme. Preliminary report

    International Nuclear Information System (INIS)

    During the carried out work of radimetric preliminary Investigation in the northeast of the uraniferous country were detected radimetric anonalias which are associated to the formation San Gregorio and Tres Islas. Later the works of prospection ratified those anomalies to which they defined in the environs other anomalies. The studies of revision of these conducted anomalies they took to conclude the necessity to carry out a detailed study of the area to that district was denominated Cerro Largo Sur

  10. Enceladus: Starting Hydrothermal Activity

    Science.gov (United States)

    Matson, D. L.; Castillo-Rogez, J. C.; Johnson, T. V.; Lunine, J. I.; Davies, A. G.

    2011-01-01

    We describe a process for starting the hydrothermal activity in Enceladus' South Polar Region. The process takes advantage of fissures that reach the water table, about 1 kilometer below the surface. Filling these fissures with fresh ocean water initiates a flow of water up from an ocean that can be self-sustaining. In this hypothesis the heat to sustain the thermal anomalies and the plumes comes from a slightly warm ocean at depth. The heat is brought to the surface by water that circulates up, through the crust and then returns to the ocean.

  11. Hydrothermal Liquefaction of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2010-12-10

    Hydrothermal liquefaction technology is describes in its relationship to fast pyrolysis of biomass. The scope of work at PNNL is discussed and some intial results are presented. HydroThermal Liquefaction (HTL), called high-pressure liquefaction in earlier years, is an alternative process for conversion of biomass into liquid products. Some experts consider it to be pyrolysis in solvent phase. It is typically performed at about 350 C and 200 atm pressure such that the water carrier for biomass slurry is maintained in a liquid phase, i.e. below super-critical conditions. In some applications catalysts and/or reducing gases have been added to the system with the expectation of producing higher yields of higher quality products. Slurry agents ('carriers') evaluated have included water, various hydrocarbon oils and recycled bio-oil. High-pressure pumping of biomass slurry has been a major limitation in the process development. Process research in this field faded away in the 1990s except for the HydroThermal Upgrading (HTU) effort in the Netherlands, but has new resurgence with other renewable fuels in light of the increased oil prices and climate change concerns. Research restarted at Pacific Northwest National Laboratory (PNNL) in 2007 with a project, 'HydroThermal Liquefaction of Agricultural and Biorefinery Residues' with partners Archer-Daniels-Midland Company and ConocoPhillips. Through bench-scale experimentation in a continuous-flow system this project investigated the bio-oil yield and quality that could be achieved from a range of biomass feedstocks and derivatives. The project was completed earlier this year with the issuance of the final report. HydroThermal Liquefaction research continues within the National Advanced Biofuels Consortium with the effort focused at PNNL. The bench-scale reactor is being used for conversion of lignocellulosic biomass including pine forest residue and corn stover. A complementary project is an international

  12. Huacas olvidadas y cerros santos: Apuntes metodológicos sobre la cartografía sagrada en los Andes del sur de Bolivia

    OpenAIRE

    Pablo Cruz

    2009-01-01

    A través de la articulación de fuentes coloniales tempranas con los registros arqueológicos y etnográficos locales, hemos identificado varios cerros sacralizados y huacas prehispánicas de las regiones de Potosí y Chuquisaca (Bolivia). A partir de tres casos: los cerros Potosí y Porco, el cerro Quiquijana y el cerro Poder de Dios, se exploran y analizan las dimensiones religiosas y políticas del culto a las montañas en los Andes surandinos.A combination of early colonial sources and local arch...

  13. Burn Severities, Fire Intensities, and Impacts to Major Vegation Types from the Cerro Grande Fire

    International Nuclear Information System (INIS)

    The Cerro Grande Fire resulted in major impacts and changes to the ecosystems that were burned. To partially document these effects, we estimated the acreage of major vegetation types that were burned at selected burn severity levels and fire intensity levels. To accomplish this, we adopted independently developed burn severity and fire intensity maps, in combination with a land cover map developed for habitat management purposes, as a basis for the analysis. To provide a measure of confidence in the acreage estimates, the accuracies of these maps were also assessed. In addition, two other maps of comparable quality were assessed for accuracy: one that was developed for mapping fuel risk and a second map that resulted from a preliminary application of an evolutionary computation software system, called GENIE. According to the burn severity map and the fire intensity map, the Cerro Grande Fire is estimated to have covered 42,885.4 acres and 42,854.7 acres, respectively. Of this, 57.0 percent was burned at low severity and 34.7 percent was burned at high severity. Similarly, 40.0 percent of the Cerro Grande Fire burned at high fire intensity, greater than 70 percent mortality, while 33.1 percent burned at moderately low intensity, 10 to 40 percent mortality. The most frequently burned cover types over the entire Cerro Grande Fire were ponderosa pine forest and mixed conifer forest, at approximately 43 percent each. However, portions of the fire that burned on Los Alamos National Laboratory (LANL) property were predominantly in ponderosa pine forests, whereas the Cerro Grande Fire burned primarily in mixed conifer forests on lands managed by other agencies. Some of the polygons of burn severities and fire intensities were extensive. The two largest burn severity polygons were 10,111 acres and 10,903 acres and these were burned at low severity. The next two largest polygons were 8999 acres (14 square miles) and 1551 acres (2.4 square miles) and both of these polygons

  14. Recycling of water, carbon, and sulfur during subduction of serpentinites: A stable isotope study of Cerro del Almirez, Spain

    Science.gov (United States)

    Alt, Jeffrey C.; Garrido, Carlos J.; Shanks, Wayne C., III; Turchyn, Alexandra; Padrón-Navarta, José Alberto; López Sánchez-Vizcaíno, Vicente; Gómez Pugnaire, María Teresa; Marchesi, Claudio

    2012-01-01

    We use the concentrations and isotope compositions of water, carbon, and sulfur in serpentinites and their dehydration products to trace the cycling of volatiles during subduction. Antigorite serpentinites from the Cerro del Almirez complex, Spain, contain 9–12 wt.% H2O and 910 ± 730 ppm sulfur, and have bulk δ18O values of 8.6 ± 0.4‰, δD = − 54 ± 5‰, and δ34S = 5.0‰, consistent with serpentinization at temperatures of ~ 200 °C by seawater hydrothermal fluids in a seafloor setting. The serpentinites were dehydrated to chlorite–harzburgite (olivine + orthopyroxene + chlorite) at 700 °C and 1.6–1.9 GPa during subduction metamorphism, resulting in loss of water, and sulfur. The chlorite–harzburgites contain 5.7 ± 1.9 wt.% H2O, and have bulk δ18O = 8.0 ± 0.9‰, and δD = − 77 ± 11‰. The rocks contain 650 ± 620 ppm sulfur having δ34S = 1.2‰. Dehydration of serpentinite resulted in loss of 5 wt.% H2O having δ18O = 8–10‰ and δD = − 27 to − 65‰, and loss of 260 ppm sulfur as sulfate, having δ34S = 14.5‰. The contents and δ13C of total carbon in the two rock types overlap, with a broad trend of decreasing carbon contents and δ13C from ~ 1300 to 200 ppm and − 9.6 to − 20.2‰. This reflects mixing between reduced carbon in the rocks (210 ppm, δ13C ≈ − 26‰) and seawater-derived carbonate (δ13C ≈ − 1‰). Our results indicate: 1) Serpentinized oceanic peridotites carry significant amounts of isotopically fractionated water, carbon and sulfur into subduction zones; 2) Subduction of serpentinites to high P and T results in loss of water, and sulfur, which can induce melting and contribute to 18O, D, and 34S enrichments and oxidation of the sub-arc mantle wedge; and 3) Isotopically fractionated water, carbon, and sulfur in serpentinite dehydration products are recycled deeper into the mantle where they can contribute to isotope heterogeneities and may be significant for volatile budgets of the deep Earth.

  15. Hydrothermal effects on montmorillonite

    International Nuclear Information System (INIS)

    Hydrothermal effects on montmorillonite clay are usually taken to have the form of conversion of this clay mineral to other species, such as illite, disregarding microstructural alteration and cementation caused by precipitation of silica and other compounds. The report is focussed on identification of the primary processes that are involved in such alteration, the release of silica and the microstructural changes associated with heating being of major interest. In the first test phase, Na montmorillonite in distilled water was investigated by XRD, rheology tests and electron microscopy after heating to 60-2250C for 0.01 to 1 year. The preliminary conclusions are that heating produces contraction of the particle network to form dense 'branches', the effect being most obvious at the highest temperature but of significance even at 60-1000C. Release of substantial amounts of silica gas been documented for temperatures exceeding 1500 and precipitation of silica was observed on cooling after the hydrothermal testing under the closed conditions that prevailed throughout the tests. The precipitates, which appeared to be amorphous and probably consisted of hydrous silica gels, were concluded to have increased the mechanical strength and caused some brittleness, particularly of the dense clays. The nature of the silica release, which is assumed to be associated with beidellitization, may be closely related to an unstable state of a certain fraction of tetrahedral silica at heat-inducted transfer between two different crystal modes of montmorillonite. (orig.)

  16. Comentarios a las ponencias de Lourenzo Fernández Prieto y Marcela Sabaté Sort

    Directory of Open Access Journals (Sweden)

    Ricardo ROBLEDO HERNÁNDEZ

    2010-02-01

    Full Text Available La ponencia de Lorenzo Fernández Prieto empieza por reivindicar los problemas del presente como punto de partida en la construcción de la historia aconsejando tener en cuenta como referente la crisis del modelo de modernización y el fin de la ideología del progreso. Resulta llamativo que al mismo tiempo, aunque sea de forma marginal, eche una lanza a favor de Fukuyama, tildado habitualmente de ideología conservadora. Pero esto, por decirlo de algún modo, es casi una anécdota puesto que el principal foco de atención es la historia rural como el ámbito más pertinente de historia transnacional. Su ponencia es un alegato más que engrosa la corriente de opinión cada vez más caudalosa en contra de la tesis del fracaso o del excepcionalismo hispánicos. Casi hace treinta años que se está hablando en esta dirección, desde que Martínez Alier y Naredo descartaron que existiera una evolución muy diferente de la agricultura española y que el comportamiento de los grandes labradores o el carácter de las instituciones fueran factores explicativos relevantes en esa supuesta diferenciación.

  17. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Hoffmann, Jessica;

    2014-01-01

    can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed by dehy-dration or decarboxylation. The chemical properties of the product are mostly de-pendent of the biomass substrate composition. Biomass consists of various com-ponents such as......Biomass is one of the most abundant sources of renewable energy, and will be an important part of a more sustainable future energy system. In addition to direct combustion, there is growing attention on conversion of biomass into liquid en-ergy carriers. These conversion methods are divided into...... biochemical/biotechnical methods and thermochemical methods; such as direct combustion, pyrolysis, gasification, liquefaction etc. This chapter will focus on hydrothermal liquefaction, where high pressures and intermediate temperatures together with the presence of water are used to convert biomass into...

  18. Archaeological fieldwork in the Bronze Age site of Cerro de la Encina (Monachil, Granada

    Directory of Open Access Journals (Sweden)

    Aranda Jiménez, Gonzalo

    2005-06-01

    Full Text Available New archaeological fieldwork has been carried out from November 2003 to May 2004 in the Bronze Age site of Cerro de la Encina, due to the interest of the regional government of Andalusia in displaying the settlement for visitors. The aim of this fieldwork has been the systematic excavation of a large settlement area partially known thanks to the excavations developed at the beginning of 1980s. A first toccupation period belonging to the Argaric Culture has been documented, highlighting specially the funerary ritual characterized by individual inhumations located below dwellings. After a gap in the occupation of the settlement a new social group belonging to the Late Bronze Age Culture of Southeast of Spain inhabits the Cerro de la Encina.

    El interés de la Consejería de Cultura de la Junta de Andalucía por la musealización del yacimiento del Cerro de la Encina ha motivado el desarrollo de nuevas investigaciones arqueológicas cuya primera fase se ha desarrollado entre Noviembre de 2003 y Mayo de 2004. Los trabajos han consistido en la excavación sistemática de un área de poblado de grandes dimensiones parcialmente conocida por las investigaciones realizadas a principios de los años 80. Los resultados han sido del máximo interés documentándose un primer momento de ocupación perteneciente a la Cultura de El Argar en el que destaca su espectacular registro funerario integrado dentro de las áreas de habitación. Tras un periodo de abandono del yacimiento se produce una nueva ocupación correspondiente a una comunidad del Bronce Final del Sureste.

  19. Geo archaeology in Cerro Lutz site, paleoenvironmental and palaeo geographic implications. Province of Entre Rios, Argentina

    International Nuclear Information System (INIS)

    The aim of this paper is to present the geo morphological evolution of the Cerro Lutz archaeological site located in the Lower Par ana Delta, Argentina River (Gualeguaychu Department). This is to add information to the paleogeographic and paleoenvironmental scheme during the occupation of site and add data to refine the regional evolution of deltaic advance against the Parana River.The geomorphology of the delta is composed of landforms resulting from fluvial modeling, coastal ( wave and tidal ) and to a lesser extent wind.They have different relative ages and dating from the late Pleistocene to the present

  20. Uranium prospecting in Cerro Partido Region-Encruzilhada do Sul Basin-RS, Brazil

    International Nuclear Information System (INIS)

    The Cerro Partido residual basin is a shallow (85 meters) and small (25km2) sedimentary basin, a remainder of the erosive cicle, enclosed in the pre-cambrian granitic rocks of the Rio Grande do Sul Shield. Grades of 0.2+ U3O8 were found in its upper-paleozoic sandstones and shales drilles for uranium. The small size and thicknesses of these concentrations prevent their economic mining. However, the different levels of the shield exposed by tectonics, the intrusive granitic, riolitic and syenitic rocks, the anomalous uranium contents in sedimentary and crystalline rocks recommend further investigations on the shield area

  1. Inestabilidad de laderas en el barrio cerros de marín, maracaibo, estado zulia, venezuela

    OpenAIRE

    Katty Montiel; Yendry González Bravo; Crismar Loaiza Arellano; Edith Gouveia Muñetón

    2008-01-01

    Se propone la aplicación de técnicas que permitan establecer una zonificación de amenaza geomorfológica para el barrio Cerros de Marín del municipio Maracaibo, expresada en términos de inestabilidad y propensión al colapso de laderas. Se efectuó un estudio de las condiciones biofísicas como litología, procesos morfogenéticos, precipitaciones y el efecto de las actividades humanas, basado en el método heurístico de Van Westen. Mediante la teledetección, inspección de campo y ...

  2. The Marianas-San Marcos vein system: characteristics of a shallow low sulfidation epithermal Au-Ag deposit in the Cerro Negro district, Deseado Massif, Patagonia, Argentina

    Science.gov (United States)

    Vidal, Conrado Permuy; Guido, Diego M.; Jovic, Sebastián M.; Bodnar, Robert J.; Moncada, Daniel; Melgarejo, Joan Carles; Hames, Willis

    2016-01-01

    The Cerro Negro district, within the Argentinian Deseado Massif province, has become one of the most significant recent epithermal discoveries, with estimated reserves plus resources of ˜6.7 Moz Au equivalent. The Marianas-San Marcos vein system contains about 70 % of the Au-Ag resources in the district. Mineralization consists of Upper Jurassic (155 Ma) epithermal Au- and Ag-rich veins of low to intermediate sulfidation style, hosted in and genetically related to Jurassic intermediate composition volcanic rocks (159-156 Ma). Veins have a complex infill history, represented by ten stages with clear crosscutting relationships that can be summarized in four main episodes: a low volume, metal-rich initial episode (E1), an extended banded quartz episode with minor mineralization (E2), a barren waning stage episode (E3), and a silver-rich late tectonic-hydrothermal episode (E4). The first three episodes are interpreted to have formed at the same time and probably from fluids of similar composition: a 290-230 °C fluid dominated by meteoric and volcanic waters (-3‰ to -0‰ δ18Owater), with <3 % NaCl equivalent salinity and with a magmatic source of sulfur (-1 to -2 ‰ δ34Swater). Metal was mainly precipitated at the beginning of vein formation (episode 1) due to a combination of boiling at ˜600 to 800 m below the paleowater table, and associated mixing/cooling processes, as evidenced by sulfide-rich bands showing crustiform-colloform quartz, adularia, and chlorite-smectite banding. During episodes 2 and 3, metal contents progressively decrease during continuing boiling conditions, and veins were filled by quartz and calcite during waning stages of the hydrothermal system, and the influx of bicarbonate waters (-6 to -8.5 ‰ δ18Owater). Hydrothermal alteration is characterized by proximal illite, adularia, and silica zone with chlorite and minor epidote, intermediate interlayered illite-smectite and a distal chlorite halo. This assemblage is in agreement with

  3. Hydrothermal Growth of Polyscale Crystals

    Science.gov (United States)

    Byrappa, Kullaiah

    In this chapter, the importance of the hydrothermal technique for growth of polyscale crystals is discussed with reference to its efficiency in synthesizing high-quality crystals of various sizes for modern technological applications. The historical development of the hydrothermal technique is briefly discussed, to show its evolution over time. Also some of the important types of apparatus used in routine hydrothermal research, including the continuous production of nanosize crystals, are discussed. The latest trends in the hydrothermal growth of crystals, such as thermodynamic modeling and understanding of the solution chemistry, are elucidated with appropriate examples. The growth of some selected bulk, fine, and nanosized crystals of current technological significance, such as quartz, aluminum and gallium berlinites, calcite, gemstones, rare-earth vanadates, electroceramic titanates, and carbon polymorphs, is discussed in detail. Future trends in the hydrothermal technique, required to meet the challenges of fast-growing demand for materials in various technological fields, are described. At the end of this chapter, an Appendix 18.A containing a more or less complete list of the characteristic families of crystals synthesized by the hydrothermal technique is given with the solvent and pressure-temperature (PT) conditions used in their synthesis.

  4. SITE CHARACTERISTICS OF THE SUMMIT OF CERRO CHAJNANTOR AT THE 5640 M ALTITUDE

    Directory of Open Access Journals (Sweden)

    K. Motohara

    2011-01-01

    Full Text Available Instituto de Astronomía de la Universidad de Tokio está promoviendo el proyecto TAO (University of Tokyo Atacama Observatory; Yoshii et al. 2010 para construir un telescopio infrarrojo en la cima de Cerro Chajnantor (altitud 5640 m en el desierto de Atacama en el Norte de Chile. Para la evaluación de las características del sitio, primero se realizó el monitoreo del tiempo atmosférico, la emisividad de nubes y el seeing durante 2006. 2007. La fracción despejada fue alta (>80% y la mediana del seeing en la banda V fue de tan solo 0."69. Un telescopio explorador de 1 m llamado miniTAO fue instalado y comenzó a observar en 2009. Con éste se han obtenido imágenes satisfactorias de Paα de hidrógeno 1.875 μm como también imágenes de 30.40 μm por primera vez desde un telescopio en tierra. Estos resultados demuestran que la cima de Cerro Chajnantor es uno de los mejores sitios para la astronomía infrarroja en la Tierra.

  5. Analysis of heavy oils: Method development and application to Cerro Negro heavy petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Carbognani, L.; Hazos, M.; Sanchez, V. (INTEVEP, Filial de Petroleos de Venezuela, SA, Caracas (Venezuela)); Green, J.A.; Green, J.B.; Grigsby, R.D.; Pearson, C.D.; Reynolds, J.W.; Shay, J.Y.; Sturm, G.P. Jr.; Thomson, J.S.; Vogh, J.W.; Vrana, R.P.; Yu, S.K.T.; Diehl, B.H.; Grizzle, P.L.; Hirsch, D.E; Hornung, K.W.; Tang, S.Y.

    1989-12-01

    On March 6, 1980, the US Department of Energy (DOE) and the Ministry of Energy and Mines of Venezuela (MEMV) entered into a joint agreement which included analysis of heavy crude oils from the Venezuelan Orinoco oil belt.The purpose of this report is to present compositional data and describe new analytical methods obtained from work on the Cerro Negro Orinoco belt crude oil since 1980. Most of the chapters focus on the methods rather than the resulting data on Cerro Negro oil, and results from other oils obtained during the verification of the method are included. In addition, published work on analysis of heavy oils, tar sand bitumens, and like materials is reviewed, and the overall state of the art in analytical methodology for heavy fossil liquids is assessed. The various phases of the work included: distillation and determination of routine'' physical/chemical properties (Chapter 1); preliminary separation of >200{degree}C distillates and the residue into acid, base, neutral, saturated hydrocarbon and neutral-aromatic concentrates (Chapter 2); further separation of acid, base, and neutral concentrates into subtypes (Chapters 3-5); and determination of the distribution of metal-containing compounds in all fractions (Chapter 6).

  6. Elemental analysis of pottery from Cerro de las Ventanas, Zacatecas, by INAA

    International Nuclear Information System (INIS)

    Fifteen ceramic fragments samples from Cerro de las Ventanas site, Zacatecas, were analyzed by instrumental neutron activation analysis. Thirty-two elements were measured: Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Ti, Th, U, V, Yb, Zn, and Zr. Cluster analysis and principal component analysis were performed on the dataset to examine similarities between samples and to establish compositional groups. The statistical analyses of the dataset suggest that the pottery samples form a unique chemically homogeneous group, with the exception of one pottery sample. The compositional data were compared to an existing Meso american ceramic database. It was found that the newly generated data fit best with data from a previous chemical analysis of pottery from the Mal paso Valley. However, despite the apparent similarity, pottery samples from the site of Cerro de las Ventanas represent a new and unique chemical fingerprint in the region. (Author)

  7. Elemental analysis of pottery from Cerro de las Ventanas, Zacatecas, by INAA

    Energy Technology Data Exchange (ETDEWEB)

    Lopez del Rio, H.; Mireles G, F. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Mendez C, R. Y. [Universidad Autonoma de Zacatecas, Unidad Academica de Antropologia, Apdo. Postal 555 Suc. C, Zacatecas (Mexico); Nicolas C, M. [Universidad Autonoma de San Luis Potosi, Coordinacion de Ciencias Sociales y Humanidades, Av. Industrias 101-A, Fracc. Talleres, 78494 San Luis Potosi (Mexico); Speakman, R. J. [Museum Conservation Institute, Smithsonian Institution, Suitland, 20746 Maryland (United States); Glascock, M. D. [Reactor Center, University of Missouri, Columbia, 65211 Missouri (United States)

    2009-10-15

    Fifteen ceramic fragments samples from Cerro de las Ventanas site, Zacatecas, were analyzed by instrumental neutron activation analysis. Thirty-two elements were measured: Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Ti, Th, U, V, Yb, Zn, and Zr. Cluster analysis and principal component analysis were performed on the dataset to examine similarities between samples and to establish compositional groups. The statistical analyses of the dataset suggest that the pottery samples form a unique chemically homogeneous group, with the exception of one pottery sample. The compositional data were compared to an existing Meso american ceramic database. It was found that the newly generated data fit best with data from a previous chemical analysis of pottery from the Mal paso Valley. However, despite the apparent similarity, pottery samples from the site of Cerro de las Ventanas represent a new and unique chemical fingerprint in the region. (Author)

  8. Models of Metabolic Community Structure in Martian Habitable Environments: Constraints from a Terrestrial Analog Acid-Sulfate Fumarole Environment, Cerro Negro Volcano, Nicaragua

    Science.gov (United States)

    Rogers, K. L.; McCollom, T. M.; Hynek, B. M.

    2014-12-01

    Microbial habitability in extreme environments on Earth is described by microscale geochemical conditions that constrain metabolic niches in concert with long-term habitat stability that is governed by dynamic geologic processes. Using terrestrial analogs to identify habitable martian environments requires correlating microscale geochemical constraints with reconstructions of past martian environments that are based on global-scale observations. While past martian environments can be characterized by primary parameters (e.g. pH, redox, mineralogy, thermal history), microbial habitability on Earth is a complex function of both primary and derived parameters (e.g. metabolic reaction energetics, chemical & thermal gradients, flow dynamics). In recent years we have been investigating acid-sulfate fumaroles at the Mars analog site, Cerro Negro Volcano, Nicaragua, where habitability is constrained by steep thermal gradients, spatially- and temporally-variable vent dynamics, and limited water and nutrient availability. The most common niche identified thus far is found in fumaroles that host mixed photosynthetic and chemosynthetic endolithic microbial communities. One such endolith is dominated by acidic red algae (Cyanidiales), aerobic bacterial heterotrophs (Ktedonobacteria), and archaeal thermoacidophiles (Hyperthermus, Caldisphaera, and Thermofilum). An analysis of the metabolic structure suggests that primary production by the red algae supports the growth of heterotrophic thermoacidophiles. Diversification among the chemoheterotrophs with respect to temperature and oxygen tolerance suggests community adaptation to environmental gradients or variable venting dynamics. Furthermore, individual cells within the endolith are silica-encrusted, providing the possibility for biosignature formation and preservation. Putative hydrothermal environments on early Mars with similar conditions could have supported endolithic communities with comparable metabolic strategies. Even

  9. Evolution of tuff ring-dome complex: the case study of Cerro Pinto, eastern Trans-Mexican Volcanic Belt

    Science.gov (United States)

    Zimmer, Brian W.; Riggs, Nancy R.; Carrasco-Núñez, Gerardo

    2010-12-01

    Cerro Pinto is a Pleistocene rhyolite tuff ring-dome complex located in the eastern Trans-Mexican Volcanic Belt. The complex is composed of four tuff rings and four domes that were emplaced in three eruptive stages marked by changes in vent location and eruptive character. During Stage I, vent clearing produced a 1.5-km-diameter tuff ring that was then followed by emplacement of two domes of approximately 0.2 km3 each. With no apparent hiatus in activity, Stage II began with the explosive formation of a tuff ring ~2 km in diameter adjacent to and north of the earlier ring. Subsequent Stage II eruptions produced two smaller tuff rings within the northern tuff ring as well as a small dome that was mostly destroyed by explosions during its growth. Stage III involved the emplacement of a 0.04 km3 dome within the southern tuff ring. Cerro Pinto's eruptive history includes sequences that follow simple rhyolite-dome models, in which a pyroclastic phase is followed immediately by effusive dome emplacement. Some aspects of the eruption, however, such as the explosive reactivation of the system and explosive dome destruction, are more complex. These events are commonly associated with polygenetic structures, such as stratovolcanoes or calderas, in which multiple pulses of magma initiate reactivation. A comparison of major and trace element geochemistry with nearby Pleistocene silicic centers does not show indication of any co-genetic relationship, suggesting that Cerro Pinto was produced by a small, isolated magma chamber. The compositional variation of the erupted material at Cerro Pinto is minimal, suggesting that there were not multiple pulses of magma responsible for the complex behavior of the volcano and that the volcanic system was formed in a short time period. The variety of eruptive style observed at Cerro Pinto reflects the influence of quickly exhaustible water sources on a short-lived eruption. The rising magma encountered small amounts of groundwater that

  10. Geología de la región del Cerro Guanaquero, Río Diamante, Mendoza Geology of Cerro Guanaquero region, Diamante River, Mendoza

    Directory of Open Access Journals (Sweden)

    Federico Fuentes

    2008-03-01

    Full Text Available El estudio realizado presenta nuevos datos sobre un sector poco conocido de la Cordillera Principal de Mendoza, en la alta cuenca del río Diamante en las adyacencias del cerro Guanaquero, y los primeros datos geocronológicos de sus rocas volcánicas. Las unidades geológicas presentes en el área se dividen en cuatro grupos principales: secuencias sedimentarias mesozoicas marinas y continentales intensamente plegadas y falladas; intrusivos y volcanitas intermedias de edad neógena; rocas volcánicas pliocenas a recientes de composición intermedia a básica, y depósitos cuaternarios inconsolidados. El cerro Guanaquero, un estratovolcán pliocuaternario intensamente erosionado por glaciares pleistocenos, con sus 4.841 metros es el rasgo orográfico más prominente. Está constituido esencialmente por andesitas grises porfíricas, piroxénicas a biotíticas. Intercaladas con las coladas andesíticas se presentan depósitos piroclásticos, aglomerados volcánicos, ignimbritas y basaltos. La datación de una andesita por el método K-Ar en roca total arrojó una edad de 1,4 ± 0,1 Ma. La deformación ándica comenzó en forma de una faja plegada y corrida de piel fina, con pliegues por despegue en el sector occidental y por propagación de falla en el oriental. La compresión al oeste de los 69º47´O terminó por invertir la fallas normales del rift mesozoico. A lo largo de este meridiano se encuentra la falla más importante de la región, la que se ha correlacionado con la falla Malargüe, bien desarrollada en latitudes más australes. Esta falla limita la faja plegada y corrida del Aconcagua, de naturaleza epidérmica, y la faja plegada y corrida de Malargüe, controlada por la inversión tectónica del basamento. El volcanismo fue muy intenso en el Plioceno y el Cuaternario, correspondiendo a un período de empinamiento de la placa oceánica subducida, en el que la región ha sido levantada pasivamente. La alta resistencia a la erosión de

  11. Natural radiation at the Cerro Solo U-Mo deposit (Argentina)

    International Nuclear Information System (INIS)

    This paper presents results of work done to establish baseline levels of natural radiation in the vicinity of the Cerro Solo U-Mo deposit, prior to proposed uranium mining activities. This was accomplished through a number of Comision Nacional de Energia Atomica (CNEA) and International Atomic Energy Agency (IAEA) supported activities, including reprocessing and back-calibration of 1978-79 airborne gamma ray spectrometry data and acquisition of new ground gamma ray spectrometry data. The Cerro Solo U-Mo deposit is located in Chubut province in the southern Patagonia region of Argentina at 43 deg 20' south latitude and 68 deg 45' west longitude, at 630 metres above sea level. The deposit occurs as conformable layers and lenses within Cretaceous sandstone and conglomerate of Los Adobes Formation (Chubut Group). These units represent a high-energy fluvial system. The mineralized horizons occur between 60 and 120 metres below surface. Cretaceous tuffs of Cerro Barcino Formation (Chubut Group) and Jurassic andesitic rocks of the Lonco Trapial formation complement the main local geology. Regionally, a thin soil horizon is developed from the underlying bedrock. In 1978-79 the CNEA collected, under contract, approximately 100,000 line kilometres of multiparameter (gamma ray spectrometry and total field magnetic) airborne geophysical data (1) between 42 deg. - 47 deg. S and 67 deg. 30' - 70 deg. W. The survey was flown at a line spacing of 1 kilometre with a gamma ray detector volume of 48 litres. Stacked profiles and contour line maps were produced from the corrected counts for potassium, uranium and thorium. In cooperation with the IAEA and the Geological Survey of Canada (GSC) the original archive data from this survey was reprocessed and back-calibrated (2) to produce a corrected digital archive to be used for ongoing and future geological mapping, mineral exploration and environmental radiation monitoring. To support regional interpretation of the airborne geophysical

  12. Hydrothermal Synthesis of Metal Silicates

    Institute of Scientific and Technical Information of China (English)

    Lii Kwang-Hwa

    2004-01-01

    Organically templated metal phosphates have been extensively studied because of interesting structural chemistry and potential applications in catalysis. However, in most cases the organic templates cannot be removed without collapse of the frameworks. This is in contrast to the high thermal stability and extensive applications of zeolites in refinery and petrochemical processes.Therefore, studies have been directed to the synthesis of transition metal silicates to produce more stable frameworks. Our synthetic methods are twofold, namely mild hydrothermal reactions in Teflon-lined autoclaves at 100-200 ℃ using organic amines as templates and high-temperature,high-pressure hydrothermal reactions in gold ampoules contained in a high-pressure reaction vessel at ca. 550 ℃ and 150 Mpa using alkali metal cations as templates. In this presentation I will report the high-temperature, high-pressure hydrothermal synthesis, crystal structures, and solid-state NMR spectroscopy of a number of new silicates of indium, uranium, and transition metals.

  13. Microwave Hydrothermal Synthesis PZT of Nanometer Crystal

    Institute of Scientific and Technical Information of China (English)

    Hongxing LIU; Hong DENG; Yan LI; Yanrong LI

    2004-01-01

    It was focused on the applications and developments of microwave hydrothermal synthesis piezoelectric ceramic powder. The microwave hydrothermal vessel was designed and manufactured. The microwave hydrothermal synthesis system was established and the PZT piezoelectric ceramic powder was synthesized. XRD and TEM have been used to characterize the products in detail. The diameter of the PZT powder particle is from 40 to 60 nm.

  14. Stratigraphic and tectonic revision of Cerro Olivo Complex located of Southeastern of Uruguay

    International Nuclear Information System (INIS)

    This paper presents a stratigraphic and tectonic revision of Cerro Olivo Complex, located in the Southeastern part of the Uruguayan Predevonian Shield. This informal lithostratigraphic unit constitutes the country rock for the emplacement of late-orogenic granitoids, during Neoproterozoic to Cambrian times. This unit groups all the lithodemes affected by deformation and metamorphism. Recent studies indicate the presence of straight gneisses of quartzo-feldspathic composition in the coast of Maldonado Department. These rocks were interpreted as the result of intense deformation in high temperature. These tectonites base a new stratigraphic insight for the complex. They allow their lithotypes to be organized by petrotectonic features, being a function of PT conditions for every last strain process

  15. Study of the atmospheric conditions at Cerro Armazones using astronomical data

    CERN Document Server

    Lakicevic, Masha; Noll, Stefan; Kausch, Wolfgang; Unterguggenberger, Stefanie; Kerber, Florian

    2016-01-01

    Aims: We studied the precipitable water vapour (PWV) content near Cerro Armazones and discuss the potential use of our technique of modelling the telluric absorbtion lines for the investigation of other molecular layers. The site is designated for the European Extremely Large Telescope (E-ELT) and the nearby planned site for the Cherenkov Telescope Array (CTA). Methods: Spectroscopic data from the Bochum Echelle Spectroscopic Observer (BESO) instrument were investigated by using line-by-line radiative transfer model (LBLRTM) radiative transfer models for the Earths atmosphere with the telluric absorption correction tool molecfit. All observations from the archive in the period from December 2008 to the end of 2014 were investigated. The dataset completely covers the El Nino event registered in the period 2009-2010. Models of the 3D Global Data Assimilation System (GDAS) were used for further comparison. Moreover, for those days with coincidence of data from a similar study with VLT/X-shooter and microwave rad...

  16. Ordenación de espacios naturales: Los Cerros de Escazú (Costa Rica)

    OpenAIRE

    Zúñiga Venegas, William

    2004-01-01

    La presente tesis doctoral se realizó en Costa Rica, país del Istmo Centroamericano que ocupa el tercer lugar en extensión entre los siete países que lo integran, con un territorio de 51.100km2 y una población de 3.824.593 habitantes. De su extensión terrestre, por lo menos el 26% (13 286km2), cuenta con algún tipo de figura legal de protección ya sea ambiental o de los recursos naturales. El área específica de la investigación se localiza en la Zona Protectora de los Cerros de Escazú; que c...

  17. Using of gamma spectrometric data for geological mapping of the Berra Bonita Cerro Azul - PR - Brazil

    International Nuclear Information System (INIS)

    The present paper discuss a geological-geophysical study at Cerro Azul district, state of Parana, Brazil, in an area of 42 Km2. The district is part of the proterozoic Ribeira belt, and it contains metamorphic rocks, two syn collisional granitic intrusions (Tres Corregos and Morro Grande) as well as Mesozoic mafic dikes. Comparing geological map and gamma spectro metrical data (K, U, Th) aerial and terrestrial, it was observed that: the thorium values and profiles seem to reflect the distinct lithologies of the area; potassium maps and profiles show the contacts between granites and host rocks, as well as, the different facies at the Tres Corregos granite; comparing the U, K and Th values of the two granite bodies, Morro Grande is more radioactive. (author)

  18. MOVIMIENTOS DE LADERA Y PLANEAMIENTO URBANÍSTICO: EL CONFLICTO DEL CERRO DEL OPE, ARCHENA (MURCIA

    Directory of Open Access Journals (Sweden)

    María Dolores Gómez Moreno

    2009-01-01

    Full Text Available Los desprendimientos son un proceso natural que afecta, de forma generalizada en el Valle de Ricote, a las laderas del tipo cantil-talud. Su peligrosidad radica en que los bloques desprendidos del escarpe ruedan con facilidad, talud abajo, cuando son descalzados por efecto de la escorrentía superfi cial o desestabilizados por movimientos sísmicos. El planeamiento urbanístico se convierte en factor inductor del riesgo al clasifi car como urbanizables y urbanos suelos que, por su ubicación en pie de ladera, deberían excluirse de cualquier proceso urbanizador. Este es el caso de Archena en el entorno inmediato del cerro del Ope.

  19. Mid amphibolite facies metamorphism of harzburgites in the Neoproterozoic Cerro Mantiqueiras Ophiolite, southernmost Brazil

    Directory of Open Access Journals (Sweden)

    HARTMANN LÉO A.

    2003-01-01

    Full Text Available Valuable information is retrieved from the integrated investigation of the field relationships, microstructure and mineral compositions of harzburgites from the Neoproterozoic Cerro Mantiqueiras Ophiolite. This important tectonic marker of the geological evolution of southernmost Brazilian Shield was thoroughly serpentinized during progressive metamorphism, because the oldest mineral assemblage is: olivine + orthopyroxene + tremolite + chlorite + chromite. This M1 was stabilized in mid amphibolite facies - 550-600ºC as calculated from mineral equilibria. No microstructural (e.g. ductile deformation of olivine or chromite or compositional (e.g. mantle spinel remnant of mantle history was identified. A metamorphic event M2 occurred in the low amphibolite facies along 100 m-wide shear zones, followed by intense serpentinization (M3 and narrow 1-3 m-wide shear zones (M4 containing asbestos.

  20. HYDROTHERMAL CRACKING OF RESIDUAL OILS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrothermal cracking of heavy oils, such as Canadian oil sand bitumen and Arabian heavy vacuum residue, as well as their model compound were performed over sulfided Ni/Al2O3 and NiMo/Al2O3 catalysts under 663~703 K and 6.0~8.0 MPa of hydrogen pressure in a batch autoclave reactor. According to the reaction mechanism of hydrothermal cracking, a small amount of free redical initiators, such as di-tert-peroxide, sulfur, etc., was added into the feed to generate free redicals at lower temperature, and obviously showed promotional effect on the conversion of hydrocarbons. The reaction mechanisms of hydrothermal cracking as well as the enhancing effect of initiators were studied by a probe reaction with 1-phenyldodecane as a model compound. The hydrothermal cracking of hydrocarbon proceeded via free redical mechanism and hydrogenating quench. The initiators might easily generate free redicals under reaction temperature, these redicals might abstract H from hydrocarbon molecule and reasonably initiate the chain reactions, therefore, promote the conversion of hydrocarbon even at lower reaction temperature.

  1. Hydrothermal precipitation of artificial violarite

    DEFF Research Database (Denmark)

    Jørgensen, W. H.; Toftlund, H.; Warner, T. E.

    The nonstoichiometric nickel-ore mineral, violarite, (Ni,Fe)3S4 was prepared as a phase-pure fine powder by a comparatively quick hydrothermal method from an aqueous solution of iron(II) acetate, nickel(II) acetate and DL-penicillamine in an autoclave at 130 °C for 45 h. Powder-XRD showed that th...

  2. Synthesis of the works of geophysical (electrical soundings) carried out in the region of the anomalies of Yerba Sola (Cerro Largo) Uruguay

    International Nuclear Information System (INIS)

    In this report has been studied geographical localization, geology, geophysics prospection, equipment and methods used and their results in Yerba Sola anomalies Province Cerro Largo and Fraile Muerto formation

  3. Reflexiones en torno a la vulnerabilidad social y residencial de los asentamiento informales de los cerros de Valparaíso, Chile

    OpenAIRE

    Bailey, Christine; Zenteno, Elizabeth

    2015-01-01

    El incendio del pasado abril del 2014 ha abierto una serie de reflexiones respecto a las condiciones y riesgos que viven miles de familias de asentamientos informales de los cerros de Valparaíso. Aplicando una serie de entrevistas en profundidad a mujeres residentes en los cerros y quebradas, el estudio apunta a comprender las condiciones que las llevaron a habitar en aquellas zonas, visualizando el lento e infinito proceso de construcción de sus viviendas y asentamiento ...

  4. A synthesis of palynological data from the Lower Permian Cerro Pelado Formation (Parana Basin, Uruguay): A record of warmer climate stages during Gondwana glaciations

    OpenAIRE

    Beri, A.; Martínez-Blanco, X.; Mourelle, D.

    2010-01-01

    This paper presents a synthesis of the palynological record in the Cerro Pelado Formation deposits (Lower Permian, Paraná basin, Cerro Largo Department, north-eastern Uruguay) based on pre-existing data and new findings. The successions studied in this formation consist mainly of non-marine to glacial-marine mudstones and sandy mudstones. The palynological assemblages yielded by 32 samples collected from two outcrops and thirty borehole samples demonstrate that not significant floral changes ...

  5. Description of a New Galapagos Giant Tortoise Species (Chelonoidis; Testudines: Testudinidae from Cerro Fatal on Santa Cruz Island.

    Directory of Open Access Journals (Sweden)

    Nikos Poulakakis

    Full Text Available The taxonomy of giant Galapagos tortoises (Chelonoidis spp. is currently based primarily on morphological characters and island of origin. Over the last decade, compelling genetic evidence has accumulated for multiple independent evolutionary lineages, spurring the need for taxonomic revision. On the island of Santa Cruz there is currently a single named species, C. porteri. Recent genetic and morphological studies have shown that, within this taxon, there are two evolutionarily and spatially distinct lineages on the western and eastern sectors of the island, known as the Reserva and Cerro Fatal populations, respectively. Analyses of DNA from natural populations and museum specimens, including the type specimen for C. porteri, confirm the genetic distinctiveness of these two lineages and support elevation of the Cerro Fatal tortoises to the rank of species. In this paper, we identify DNA characters that define this new species, and infer evolutionary relationships relative to other species of Galapagos tortoises.

  6. Nueva edad de la base del grupo Chubut en la mena uranífera Cerro Solo, provincia del Chubut

    Directory of Open Access Journals (Sweden)

    Nilda Marveggio

    2013-09-01

    Full Text Available En este trabajo se analizan las características litológicas de la roca hospedante de la mineralización de uranio del yacimiento Cerro Solo, que corresponde al miembro inferior de la Formación Los Adobes, unidad basal del Grupo Chubut en su sector norte. Se analiza la asociación de polen angiospérmico de allí recuperada, y en base a ese análisis, se establece una edad albiana temprana para la asociación polínica, que determina una edad más joven que la considerada hasta el momento para el inicio de la depositación de las sedimentitas del Grupo Chubut en el depocentro del yacimiento Cerro Solo.

  7. Los marsupiales (Mammalia) del Mioceno Superior de la Formación Cerro Azul (Provincia de La Pampa, Argentina)

    OpenAIRE

    Visconti, G; Montalvo, C. I.; Goin, F J

    2000-01-01

    We describe the most complete South American marsupial association of Huayquerian Age (late Miocene). Specimens were recovered from several new localities of central and northern La Pampa province (central Argentina), at levels assignable to Cerro Azul Fm.: Bajo Giuliani, Quehué, Telén, El Guanaco, and Laguna Chillhué. Loessoid sediments studied from this formation are indicative of lacustrine deposits overlaid by eolian levels bearing evidences of pedogenesis. A study of these...

  8. ‘Looking at risk with both eyes’: health and safety in the Cerro Rico of Potosí (Bolivia)

    OpenAIRE

    Lopez-Trueba, Mei

    2014-01-01

    This thesis is concerned with core assumptions and practices in dominant approaches to Occupational Health and Safety (hereafter, OHS). I critically evaluate these through an anthropological exploration of the everyday perceptions, experiences and practices related to OHS risks amongst the cooperative miners employed in the Cerro Rico of Potosi (Bolivian Highlands). Drawing on 17 months of ethnographic fieldwork conducted between 2009 and 2011, the thesis examines the lives and livelihood...

  9. Hydrothermal carbonization of waste biomass

    OpenAIRE

    Basso, Daniele

    2016-01-01

    Hydrothermal carbonization (in acronym, HTC) is a thermochemical conversion process through which it is possible to directly transform wet organic substrates into a carbonaceous material, referred as hydrochar. Hydrochar has chemical and physical characteristics that make it similar to fossil peats and lignite. Depending on the process conditions, mostly temperature and residence time, this material can be enriched in its carbon content, modifying its structure and providing it interesting ch...

  10. Salt effects in hydrothermal synthesis

    OpenAIRE

    Avola, Sabine

    2012-01-01

    This work focuses on hydrothermal water as solvent and reaction medium. Water is abundant, non-toxic and environmentally benign, but at room temperature it does not dissolve most of the materials used in organic chemistry. When raising the temperature, though, its strong hydrogen bonds are weakened. At supercritical conditions water behaves similar to an unpolar solvent. However, high pressure, temperature and corrosion are technical challenges when reaching supercritical conditions. Al...

  11. Sustainable carbon materials from hydrothermal processes

    CERN Document Server

    Titirici, Maria-Magdalena

    2013-01-01

    The production of low cost and environmentally friendly high performing carbon materials is crucial for a sustainable future. Sustainable Carbon Materials from Hydrothermal Processes describes a sustainable and alternative technique to produce carbon from biomass in water at low temperatures, a process known as Hydrothermal Carbonization (HTC). Sustainable Carbon Materials from Hydrothermal Processes presents an overview of this new and rapidly developing field, discussing various synthetic approaches, characterization of the final products, and modern fields of application fo

  12. The Final Days of Paracas in Cerro del Gentil, Chincha Valley, Peru

    Science.gov (United States)

    2016-01-01

    This article describes and analyzes a highly significant archaeological context discovered in a late Paracas (400–200 BCE) sunken patio in the monumental platform mound of Cerro Gentil, located in the Chincha Valley, Peru. This patio area was used for several centuries for ritual activities, including large-scale feasting and other public gatherings. At one point late in this historical sequence people deposited a great deal of objects in what is demonstrably a single historical event. This was quickly followed by a series of minor events stratigraphically immediately above this larger event. This entire ritual process included the consumption of liquids and food, and involved the offering of whole pottery, pottery fragments, botanical remains, bone, lithics, baskets, pyro-engraved gourds, mummies, and other objects. We interpret these events as an “abandonment ceremony” or “termination ritual” during the late Paracas period, one that may have lasted for weeks or even months. The subsequent Topará occupation at the site (ca. 200 BCE- AD 100) involved the architectural enhancement of the mound area, but the pattern of use of the patio itself ended. Such a termination ritual signals a reorganization in the regional political structure of Paracas society. PMID:27144824

  13. New mammalian records in the Parque Nacional Cerros de Amotape, northwestern Peru

    Directory of Open Access Journals (Sweden)

    Cindy M. Hurtado

    2015-04-01

    Full Text Available The Pacific Tropical Rainforest and Equatorial Dry Forest are found only in southern Ecuador and northern Peru, and are among the most poorly known ecosystems of South America. Even though these forests are protected in Parque Nacional Cerros de Amotape (PNCA, they are threatened by fragmentation because of farming and agriculture. The aim of this study was to determine the medium and large mammalian species richness, using transect census, camera trapping, and specimen bone collection. Nine transects were established and 21 camera trap stations were placed along 16 km2 in three localities of PNCA, from August 2012 to April 2013. Total sampling effort was 215 km of transects and 4077 camera-days. We documented 22 species; including 17 with camera trapping, 11 with transect census, and 10 with specimen collection.  Camera traps were the most effective method, and four species (Dasyprocta punctata, Cuniculus paca, Leopardus wiedii and Puma concolor were documented only with this method. This comprised the first Peruvian record for Dasyprocta punctata, and the first record for the western slope of the Peruvian Andes for Cuniculus paca. Also, both specimen collections and sightings confirm the presence of Potos flavus, first record in the western slope of the Peruvian Andes. Panthera onca, Tremarctos ornatus and Saimiri sciureus are considered locally extinct, while several species are in need of further research. We highlight the importance of the high diversity of this rainforests and encourage local authorities to give the area the highest priority in conservation.

  14. Monitoring the atmospheric throughput at Cerro Tololo Inter-American Observatory with aTmCam

    CERN Document Server

    Li, Ting; Marshall, J L; Nagasawa, D Q; Carona, D W; Boada, S

    2014-01-01

    We have built an Atmospheric Transmission Monitoring Camera (aTmCam), which consists of four telescopes and detectors each with a narrow-band filter that monitors the brightness of suitable standard stars. Each narrowband filter is selected to monitor a different wavelength region of the atmospheric transmission, including regions dominated by the precipitable water vapor and aerosol optical depth. The colors of the stars are measured by this multi narrow-band imager system simultaneously. The measured colors, a model of the observed star, and the measured throughput of the system can be used to derive the atmospheric transmission of a site on sub-minute time scales. We deployed such a system to the Cerro Tololo Inter-American Observatory (CTIO) and executed two one-month-long observing campaigns in Oct-Nov 2012 and Sept-Oct 2013. We have determined the time and angular scales of variations in the atmospheric transmission above CTIO during these observing runs. We also compared our results with those from a G...

  15. Forecast of surface layer meteorological parameters at Cerro Paranal with a mesoscale atmospherical model

    CERN Document Server

    Lascaux, Franck; Fini, Luca

    2015-01-01

    This article aims at proving the feasibility of the forecast of all the most relevant classical atmospherical parameters for astronomical applications (wind speed and direction, temperature) above the ESO ground-base site of Cerro Paranal with a mesoscale atmospherical model called Meso-Nh. In a precedent paper we have preliminarily treated the model performances obtained in reconstructing some key atmospherical parameters in the surface layer 0-30~m studying the bias and the RMSE on a statistical sample of 20 nights. Results were very encouraging and it appeared therefore mandatory to confirm such a good result on a much richer statistical sample. In this paper, the study was extended to a total sample of 129 nights between 2007 and 2011 distributed in different parts of the solar year. This large sample made our analysis more robust and definitive in terms of the model performances and permitted us to confirm the excellent performances of the model. Besides, we present an independent analysis of the model p...

  16. Characterization of the sodium layer at Cerro Pachon, and impact on laser guide star performance

    CERN Document Server

    Neichel, Benoit; Callingham, Joseph; Rigaut, Francois; Winge, Claudia; Trancho, Gelys; 10.1093/mnras/sts631

    2013-01-01

    Detailed knowledge of the mesopheric sodium layer characteristics is crucial to estimate and optimize the performance of Laser Guide Star (LGS) assisted Adaptive Optics (AO) systems. In this paper, we present an analysis of two sets of data on the mesospheric sodium layer. The first set comes from a laser experiment that was carried out at Cerro Tololo to monitor the abundance and altitude of the mesospheric sodium in 2001, during six runs covering a period of one year. This data is used to derive the mesospheric sodium column density, the sodium layer thickness and the temporal behavior of the sodium layer mean altitude. The second set of data was gathered during the first year of the Gemini MCAO System (GeMS) commissioning and operations. GeMS uses five LGS to measure and compensate for atmospheric distortions. Analysis of the LGS wavefront sensor data provides information about the sodium photon return and the spot elongation seen by the WFS. All these parameters show large variations on a yearly, nightly ...

  17. Research Experiences for Undergraduates at Cerro Tololo Inter-American Observatory

    Science.gov (United States)

    Hoard, D. W.; Smith, R. C.

    1999-12-01

    Each year, Cerro Tololo Inter-American Observatory (CTIO) hosts a Research Experiences for Undergraduates (REU) program funded by the National Science Foundation. In general, REU programs bring a group of undergraduate students to the host institute for 10 weeks, where they are teamed-up with staff members to perform research projects. Unlike REU programs at other U.S. institutions, the CTIO program takes place outside the United States and during the southern summer/northern winter months. This offers students not only a chance to perform research and participate in the day-to-day life at a major astronomical observatory, but also provides a unique exposure to a foreign culture and an option for students who can take advantage of a non-traditional work experience during the academic year. CTIO REU students also benefit from interaction with their Chilean counterparts participating in the Prácticas de Investigación en Astronomía, an REU-like program operated by CTIO for Chilean undergraduates. Since 1995, CTIO has hosted 16 REU students (with 4 more coming in 2000). Thirteen (and counting) publications have resulted from CTIO REU projects; all 4 REU students in the 1999 program attended the 194th AAS meeting to present posters based on their projects. We present here an overview of the REU program at CTIO.

  18. Research Experiences for Undergraduates at Cerro Tololo Inter-American Observatory

    Science.gov (United States)

    Hoard, D. W.; Smith, R. C.

    2000-12-01

    Each year, Cerro Tololo Inter-American Observatory (CTIO), located in La Serena, Chile, hosts a Research Experiences for Undergraduates (REU) Program funded by the National Science Foundation. In general, REU programs bring a group of undergraduate students to the host institute for 10 weeks, where they are teamed-up with staff members to perform research projects. Unlike REU programs at other U.S. institutions, the CTIO program takes place outside the United States and during the southern summer/northern winter months of January--March. This offers students not only a chance to perform research and participate in the day-to-day life at a major astronomical observatory, but also provides a unique exposure to a foreign culture and an option for students who can take advantage of a non-traditional work experience during the academic year. CTIO REU students also benefit from interaction with their Chilean counterparts participating in the Prácticas de Investigación en Astronomía, an REU-like program operated by CTIO for Chilean undergraduates. Since 1995, CTIO has hosted 20 REU students (with 4 more coming in 2001). Twenty (and counting) publications have resulted from CTIO REU projects. In addition, since 1999, 100% of the CTIO REU students have presented the results of their research projects at meetings of the American Astronomical Society. We present here an overview of the REU program at CTIO.

  19. The Final Days of Paracas in Cerro del Gentil, Chincha Valley, Peru.

    Science.gov (United States)

    Tantaleán, Henry; Stanish, Charles; Rodríguez, Alexis; Pérez, Kelita

    2016-01-01

    This article describes and analyzes a highly significant archaeological context discovered in a late Paracas (400-200 BCE) sunken patio in the monumental platform mound of Cerro Gentil, located in the Chincha Valley, Peru. This patio area was used for several centuries for ritual activities, including large-scale feasting and other public gatherings. At one point late in this historical sequence people deposited a great deal of objects in what is demonstrably a single historical event. This was quickly followed by a series of minor events stratigraphically immediately above this larger event. This entire ritual process included the consumption of liquids and food, and involved the offering of whole pottery, pottery fragments, botanical remains, bone, lithics, baskets, pyro-engraved gourds, mummies, and other objects. We interpret these events as an "abandonment ceremony" or "termination ritual" during the late Paracas period, one that may have lasted for weeks or even months. The subsequent Topará occupation at the site (ca. 200 BCE- AD 100) involved the architectural enhancement of the mound area, but the pattern of use of the patio itself ended. Such a termination ritual signals a reorganization in the regional political structure of Paracas society. PMID:27144824

  20. Optical and infrared observations of SN 1987A from Cerro Tololo Inter-American Observatory

    International Nuclear Information System (INIS)

    Results from optical and infrared observations of SN 1987A obtained at Cerro Tololo Inter-American Observatory over the first seven months since core collapse are reviewed. Around 130 days after outburst, the bolometric light curve began to smoothly decline at a rate of ∼ 0.01 mag day-1, providing dramatic confirmation of the prediction that radioactivity had powered the optical display after the first month./ the peculiar color changes are kinks observed beginning on the 25th day probably signaled the initial release of trapped energy from mass 56 material. The bolometric luminosity of SN 1987A was unusually low at first, but reached a value more typical of other type II supernovae by the time that the final exponential decline had begun. Over much of the period covered by these observations, the optical and infrared spectra were characterized by strong absorption lines of Ba II and Sr II. Comparison with the spectra of other type II supernovae at similar stages of evolution supports the suggestion that s-processed elements were enriched in the hydrogen envelope of the progenitor, Sanduleak - 69 degrees 202

  1. Subsurface Connections and Magma Mixing as revealed by Olivine- and Pyroxene-Hosted Melt Inclusions from Cerro Negro Volcano and the Las Pilas-El Hoyo Complex, Nicaragua.

    Science.gov (United States)

    Venugopal, S.; Moune, S.; Williams-Jones, G.

    2015-12-01

    Cerro Negro, the youngest volcano in the Central American Volcanic Belt, is a polygenetic cinder cone with relatively frequent explosive basaltic eruptions. Las Pilas, on the other hand, is a much larger and older complex with milder and less frequent eruptions. Based on historical data, these two closely spaced volcanoes have shown concurrent eruptive behavior, suggesting a subsurface connection. To further investigate this link, melt inclusions, which are blebs of melt trapped in growing crystals, were the obvious choice for optimal comparison of sources and determination of pre-eruptive volatile contents and magmatic conditions. Olivine-hosted inclusions were chosen for both volcanoes and pyroxene-hosted inclusions were also sampled from Las Pilas to represent the evolved melt. Major, volatile and trace elements reveal a distinct geochemical continuum with Cerro Negro defining the primitive end member and Las Pilas representing the evolved end member. Volatile contents are high for Cerro Negro (up to 1260 ppm CO2, 4.27 wt% H2O and 1700 ppm S) suggesting that volatile exsolution is likely the trigger for Cerro Negro's explosive eruptions. Las Pilas volatile contents are lower but consistent with degassing and evolutionary trends shown by major oxides. Trace element contents are rather unique and suggest Cerro Negro magmas fractionally crystallize while Las Pilas magmas are the products of mixing. Magmatic conditions were estimated with major and volatile contents: at least 2.4 kbar and 1170 °C for Cerro Negro melts and 1.3 kbar and 1130 °C for Las Pilas melts with an overall oxygen fugacity at the NNO buffer. In combination with available literature data, this study suggests an interconnected subsurface plumbing system and thus Cerro Negro should be considered as the newest vent within the Las Pilas-El Hoyo Complex.

  2. Whole Algae Hydrothermal Liquefaction Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, M.; Davis, R.; Jones, S.

    2013-03-01

    This technology pathway case investigates the feasibility of using whole wet microalgae as a feedstock for conversion via hydrothermal liquefaction. Technical barriers and key research needs have been assessed in order for the hydrothermal liquefaction of microalgae to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

  3. ESTRATEGIA DE REMONTAJE APLICADA SOBRE EL REGISTRO CERÁMICO DEL SITIO LOS TRES CERROS 1 (DELTA SUPERIOR DEL RÍO PARANÁ) / Refitting applied to pottery from Los Tres Cerros 1 site (Upper Delta of Paraná River)

    OpenAIRE

    Violeta Soledad Di Prado; Canela Castro

    2014-01-01

    El sitio arqueológico Los Tres Cerros 1 se encuentra ubicado en el departamento Victoria, Entre Ríos, y consiste en una estructura monticular con una compleja historia ocupacional. La abundancia y fragmentación del registro cerámico del sitio, llevaron a aplicar la estrategia de remontajes, con el propósito de reconstruir la historia de vida de las vasijas e identificar las prácticas humanas y los agentes naturales que actuaron en la configuración del depósito. Sobre una muestra del total de ...

  4. ESTUDIO ERGONÓMICO DEL PUESTO DE TRABAJO DE RECOLECTOR DE CÍTRICOS EN LA FINCA "HACIENDA EL CERRO", PERTENECIENTE A LA SOCIEDAD; EXPLOTACIONES EL CERRO S.A.

    OpenAIRE

    Guardado-Moro, José Ramón

    2013-01-01

    El objeto del TFM que me ocupa, está basado en el estudio de una empresa agraria, en concreto una empresa dedicada a la producción de cítricos, dicha empresa se denominada EXPLOTACIONES EL CERRO, S.A., cuyo centro de trabajo recibe el nombre de “finca El Cerro”. Dicha finca está compuesta de 150 hectáreas, todas ellas ocupadas por cítricos de diferentes variedades. Cada una de estas variedades tiene una época de recolección diferente, lo que permite a la empresa sacar fruta al mercado d...

  5. Subduction and exhumation structures preserved in Cerro del Almirez HP metaserpentinites (Betic Cordillera, SE Spain)

    Science.gov (United States)

    Jabaloy-Sánchez, Antonio; López Sánchez-Vizcaíno, Vicente; Gómez-Pugnaire, María Teresa; Padrón-Navarta, José Alberto; Garrido, Carlos J.

    2014-05-01

    The Cerro del Almirez massif (Nevado-Filábride Complex, Betic Cordillera, SE Spain) is composed of antigorite serpentinite and chlorite harzburgite separated by a thin reaction front in a paleo-subduction setting. Structural analysis of ultramafic lithologies and metasedimentary host rocks provides information on the tectonic evolution of this massif during prograde metamorphism in a subduction zone and during subsequent exhumation. Here we report for the first time HP structures related to a subduction event underwent by ultramafic rocks of the Nevado-Filábride Complex. The oldest subduction-related structures are preserved in Atg-serpentinites: a penetrative S1 foliation and associated L1 stretching lineation were formed in a non-coaxial regime with a top-to-the-W sense of shearing. This planar linear fabric is crosscut by olivine ± Ti-clinohumite veins formed during the prograde breakdown of brucite and pre-metamorphic clinopyroxene at temperatures ranging from 465 to 500 ºC [1]. Veins occur as a system of decimetric long joints, some of them hybrid open and sheared veins with associated drag folds. They recorded embrittlement processes due to the release of 6% vol. H2O of the rock. S1 foliation can, however, be simultaneous with or be overgrown by olivine and/or tremolite porphyroblasts, product of the prograde reaction Di + Atg → Fo + Tr + H2O, which occurred at T > 600 ºC and P = 1.7-1.9 GPa [1]. Generation of S1/L1 fabric was followed by static annealing at ca. 680 ºC and 1.6-1.9 GPa [2]. The S1/L1 fabric in Atg-serpentinite is crosscut by the Atg-out isograd and overgrown by the Atg-serpentinite dehydration products that gave place to Chl-harzburgite. Peak metamorphic conditions of the Chl-harzburgite assemblage reached 680-710 ºC and 1.6-1.9 GPa [3]. Prograde Chl-harzburgite is crosscut by sets of conjugate zones associated to grain-size reduction of olivine grains [3]. These grain size reduction zones are interpreted as brittle structures

  6. Shallow earthquake inhibits unrest near Chiles-Cerro Negro volcanoes, Ecuador-Colombian border

    Science.gov (United States)

    Ebmeier, Susanna K.; Elliott, John R.; Nocquet, Jean-Mathieu; Biggs, Juliet; Mothes, Patricia; Jarrín, Paúl; Yépez, Marco; Aguaiza, Santiago; Lundgren, Paul; Samsonov, Sergey V.

    2016-09-01

    Magma movement or reservoir pressurisation can drive swarms of low-magnitude volcano-tectonic earthquakes, as well as occasional larger earthquakes (>M5) on local tectonic faults. Earthquakes >M5 near volcanoes are challenging to interpret in terms of evolving volcanic hazard, but are often associated with eruptions, and in some cases enhance the ascent of magma. We present geodetic observations from the first episode of unrest known to have occurred near Chiles and Cerro Negro de Mayasquer volcanoes on the Ecuador-Colombian border. A swarm of volcano-tectonic seismicity in October 2014 culminated in a Mw 5.6 earthquake south of the volcanoes. Satellite radar data spanning this earthquake detect displacements that are consistent with dextral oblique slip on a reverse fault at depths of 1.4-3.4 km within a SSW-NNE trending fault zone that last ruptured in 1886. GPS station measurements capture ∼20 days of uplift before the earthquake, probably originating from a pressure source ∼10-15 km south of Volcán Chiles, at depths exceeding 13 km. After the Mw 5.6 earthquake, uplift ceased and the rate of seismicity began to decrease. Potential mechanisms for this decline in activity include a decrease in the rate of movement of magma into the shallow crust, possibly caused by the restriction of fluid pathways. Our observations demonstrate that an earthquake triggered during volcanic unrest can inhibit magmatic processes, and have implications for the hazard interpretation of the interactions between earthquakes and volcanoes.

  7. Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes

    Directory of Open Access Journals (Sweden)

    P. Ginot

    2006-01-01

    Full Text Available A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l, 30°08' S, 69°55' W was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Assuming that, like measured during the field campaign, the enrichment of chloride was always related to sublimation, the chemical record along the ice core may be applied to reconstruct the history of such secondary processes linked to the past climatic conditions over northern Chile. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation is related with the Southern Oscillation Index (SOI: higher net-accumulation during El-Niño years and more sublimation during La Niña years. The deepest part of the ice record shows a time discontinuity; with an ice body deposited under different climatic conditions: 290 mm higher precipitation but with reduced seasonal distribution (+470 mm in winter and –180 mm in summer and –3°C lower mean annual temperature. Unfortunately, its age is unknown. The comparison with regional proxy data however let us conclude that the glacier buildup did most likely occur after the dry mid-Holocene.

  8. Water Quality Monitoring in the Cerro Solo U District Chubut, Argentina

    International Nuclear Information System (INIS)

    Full text: This work was carried out on behalf of the European Union INCO DC project called Water Quality in Mining Areas of Latin America. The Cerro Solo U district is located in Chubut province in the southern Patagonia region of Argentina at 43o20' south latitude and 68o45' west longitude, at 630 metres above sea level and covering an area of 420 square kilometers. The main deposit occurs as conformable layers and lenses within Cretaceous sandstones and conglomerates of the Los Adobes formation (Chubut Group). These units represent a high-energy fluvial system. The mineralized horizons occur between 60 and 120 metres below the surface. The average grade is 0.4% U, and the uranium resources (RAR + EAR I) are calculated in 4 600 tonnes of recoverable uranium. Cretaceous tuffs of the Cerro Barcino formation (Chubut Group) and Jurassic andesitic rocks of the Lonco Trapial formation complement the main local geology. In this area, a water quality monitoring network was established in order to evaluate the pre-mining hydro-geochemistry baseline of the district. The sampling stations include: exploration boreholes (8), springs and wells (5), streams (2) and an artesian well (1). The boreholes belong to the Cerro Solo deposit and represent the groundwater in contact with the mineralized bodies. The spring and well stations are located close to the deposit area and provide a source of water for human and animal consumption in the surrounding farms. The stream stations are located in the Chubut River, which is the only perennial stream in the region and represents the background for surface water quality. Finally, the artesian well represents a mineralized water source in the study area. In order to evaluate the seasonal variations in the water composition, the samples were collected both in the wet and dry periods of the year. Water samples were filtered (0.4 μm), and collected in pre-cleaned, high-density polyethylene bottles. Temperature, pH, Eh, dissolved oxygen

  9. Structural control on geothermal circulation in the Cerro Tuzgle-Tocomar geothermal volcanic area (Puna plateau, Argentina)

    Science.gov (United States)

    Giordano, Guido; Pinton, Annamaria; Cianfarra, Paola; Baez, Walter; Chiodi, Agostina; Viramonte, José; Norini, Gianluca; Groppelli, Gianluca

    2013-01-01

    The reconstruction of the stratigraphical-structural framework and the hydrogeology of geothermal areas is fundamental for understanding the relationships between cap rocks, reservoir and circulation of geothermal fluids and for planning the exploitation of the field. The Cerro Tuzgle-Tocomar geothermal volcanic area (Puna plateau, Central Andes, NW Argentina) has a high geothermal potential. It is crossed by the active NW-SE trans-Andean tectonic lineament known as the Calama-Olacapato-Toro (COT) fault system, which favours a high secondary permeability testified by the presence of numerous springs. This study presents new stratigraphic and hydrogeological data on the geothermal field, together with the analysis from remote sensed image analysis of morphostructural evidences associated with the structural framework and active tectonics. Our data suggest that the main geothermal reservoir is located within or below the Pre-Palaeozoic-Ordovician basement units, characterised by unevenly distributed secondary permeability. The reservoir is recharged by infiltration in the ridges above 4500 m a.s.l., where basement rocks are in outcrop. Below 4500 m a.s.l., the reservoir is covered by the low permeable Miocene-Quaternary units that allow a poor circulation of shallow groundwater. Geothermal fluids upwell in areas with more intense fracturing, especially where main regional structures, particularly NW-SE COT-parallel lineaments, intersect with secondary structures, such as at the Tocomar field. Away from the main tectonic features, such as at the Cerro Tuzgle field, the less developed network of faults and fractures allows only a moderate upwelling of geothermal fluids and a mixing between hot and shallow cold waters. The integration of field-based and remote-sensing analyses at the Cerro Tuzgle-Tocomar area proved to be effective in approaching the prospection of remote geothermal fields, and in defining the conceptual model for geothermal circulation.

  10. La «embajada oficiosa» de Indalecio Prieto en México durante la presidencia de Lázaro Cárdenas, 1939-1940

    Directory of Open Access Journals (Sweden)

    Mateos, Abdón

    2003-08-01

    Full Text Available The author tries to set Indalecio Prieto’s mission in Cárdenas’ Mexico within its political context, emphasizing the background of the relationship between the Spanish republican socialists and the Mexican leftist nationalists and its development from the 1920’s onwards. The present monograph is an account of the JARE’s management and of President L. Cárdenas’ policy towards the Spanish republican refugees until the beginning of Ávila Camacho’s presidency

    El autor contextualiza la misión de Indalecio Prieto en el México cardenista, destacando los antecedentes de las relaciones entre los republicanos-socialistas españoles y la izquierda nacionalista mexicana establecidas desde los años veinte. La monografía analiza la gestión de la JARE y la política de Lázaro Cárdenas hacia los refugiados republicanos españoles hasta el comienzo de la presidencia de Manuel Ávila Camacho.

  11. Dieta de murciélagos nectarívoros del Parque Nacional Cerros de Amotape, Tumbes

    OpenAIRE

    Edith Arias; Richard Cadenillas; Víctor Pacheco

    2011-01-01

    En el Perú se reporta la presencia de 18 especies de murciélagos nectarívoros, sin embargo se cuenta con poca información sobre la dieta de estas especies. En este estudio se reporta por primera vez la dieta de los nectarívoros Glossophaga soricina, Lonchophylla hesperia y Anoura geoffroyi en el bosque seco ecuatorial y del bosque tropical del Pacífico del Parque Nacional Cerros de Amotape, Tumbes. Analizamos 21 contenidos gastrointestinales e identificamos ocho morfotipos de polen pertenecie...

  12. Palaeoenvironment reconstruction, volcanic evolution and geochronology of the Cerro Blanco subcomplex, Nevados de Chillan volcanic complex, Central Chile

    OpenAIRE

    Mee, Katy; Gilbert, Jennie S.; McGarvie, David W.; Naranjo, Jose A.; Pringle, Malcolm S.

    2009-01-01

    Nevados de Chillán Volcanic Complex, central Chile, has been active for at least 640 ka—a period spanning a number of glacial and interglacial periods. Geologic mapping, radiometric dating and geochemical analysis have identified six new volcanic units and produced four new 40Ar/39Ar ages for Cerro Blanco, the northern subcomplex of Nevados de Chillán volcano. Compositions range from dacite to basaltic-andesite and a new geologic map is presented. Examination of lava fracture structures on bo...

  13. Los marsupiales (Mammalia) del Mioceno Superior de la formación Cerro Azul (Provincia de la Pampa, Argentina)

    OpenAIRE

    Goin, Francisco Javier; Montalvo, Claudia; Visconti, G

    2000-01-01

    Se describe la asociación de marsupiales sudamericanos fósiles de edad Huayqueriense (Mioceno tardío) más completa hasta ahora conocida. Los ejemplares fueron exhumados de varias localidades fosilíferas nuevas del centro y norte de la provincia de La Pampa (Argentina central), en sedimentos asignables a la Formación Cerro Azul: Bajo Giuliani, Quehué, Telén, El Guanaco y Laguna Chillhué. El conjunto de las sedimentitas loessoides analizadas en los diferentes afloramientos de esta formación ind...

  14. Importaciones áticas del siglo V a.C. del Cerro del Prado (Algeciras, Cádiz)

    OpenAIRE

    Cabrera, Paloma; Perdigones, Lorenzo

    1996-01-01

    In this paper we analyze a group of Attic imports, found in the excavations of Cerro del Prado, a settlement situated in the Bahía de Algeciras (Cádiz). The great interest of this group lies in the fact that it belongs to a particular chronological period, the last third of the 5th century B.C., as we have not found later imports, and in the almost exclusive presence of black glazed vases, which gives US an idea of a very definitive demand of the punic society of the Iberian Peninsula regardi...

  15. TITAN2D simulations of pyroclastic flows at Cerro Machín Volcano, Colombia: Hazard implications

    Science.gov (United States)

    Murcia, H. F.; Sheridan, M. F.; Macías, J. L.; Cortés, G. P.

    2010-03-01

    Cerro Machín is a dacitic tuff ring located in the central part of the Colombian Andes. It lies at the southern end of the Cerro Bravo-Cerro Machín volcanic belt. This volcano has experienced at least six major explosive eruptions during the last 5000 years. These eruptions have generated pyroclastic flows associated with Plinian activity that have traveled up to 8 km from the crater, and pyroclastic flows associated with Vulcanian activity with shorter runouts of 5 km from the source. Today, some 21,000 people live within a 8 km radius of Cerro Machín. The volcano is active with fumaroles and has shown increasing seismic activity since 2004, and therefore represents a potentially increasing threat to the local population. To evaluate the possible effects of future eruptions that may generate pyroclastic density currents controlled by granular flow dynamics we performed flow simulations with the TITAN2D code. These simulations were run in all directions around the volcano, using the input parameters of the largest eruption reported. The results show that an eruption of 0.3 km 3 of pyroclastic flows from a collapsing Plinian column would travel up to 9 km from the vent, emplacing a deposit thicker than 60 m within the Toche River valley. Deposits >45 m thick can be expected in the valleys of San Juan, Santa Marta, and Azufral creeks, while 30 m thick deposits could accumulate within the drainages of the Tochecito, Bermellón, and Coello Rivers. A minimum area of 56 km 2 could be affected directly by this kind of eruption. In comparison, Vulcanian column-collapse pyroclastic flows of 0.1 km 3 would travel up to 6 km from the vent depositing >45 m thick debris inside the Toche River valley and more than 30 m inside the valleys of San Juan, Santa Marta, and Azufral creeks. The minimum area that could be affected directly by this kind of eruption is 33 km 2. The distribution and thickness of the deposits obtained by these simulations are consistent with the hazard

  16. Estudio de la líqueno flora encontrada en el Cerro de Quininí, Tibacuy, Cundinamarca

    OpenAIRE

    Hormaza Francisco; Vivas Oscar; Parra Alejandro

    2000-01-01

    Se realizó un muestreo de la liquen o flora del cerro de Quininí, Tibacuy, Cundinamarca para estudiar las características morfológicas externas de los géneros de líquenes encontrados en el. A su vez se hizo la revisión bibliográfica acerca de dichos géneros, datando así la riqueza de líquenes en la zona con 8 géneros en total y con respecto al papel de bioindicadores se mostró el grado de intervención para el lugar.

  17. Estructura, composición y diversidad de la selva baja caducifolia del Cerro Verde, Nizanda (Oaxaca), México

    OpenAIRE

    José Antonio Gallardo Cruz; Meave, Jorge A.; Eduardo A. Pérez García

    2005-01-01

    En este estudio se describe la estructura, la composición florística y los patrones de diversidad de la selva baja caducifolia del Cerro Verde, localizado en Nizanda (Istmo de Tehuantepec, Oaxaca, México). En 30 parcelas de 100 m2 se censaron las plantas leñosas con DAP #8805; 1 cm (estrato alto), y en cinco subcuadros de 4 m2 dentro de cada una se censaron las plantas con DAP 1 cm, pero con altura 30 cm (estrato bajo). Se encontraron 194 especies distribuidas en 52 familias. La riqueza de...

  18. Dynamics of the Yellowstone hydrothermal system

    Science.gov (United States)

    Hurwitz, Shaul; Lowenstern, Jacob B.

    2014-01-01

    The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a hydrothermal system that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and hydrothermal explosion craters. The diverse chemical and isotopic compositions of waters and gases derive from mantle, crustal, and meteoric sources and extensive water-gas-rock interaction at variable pressures and temperatures. The thermal features are host to all domains of life that utilize diverse inorganic sources of energy for metabolism. The unique and exceptional features of the hydrothermal system have attracted numerous researchers to Yellowstone beginning with the Washburn and Hayden expeditions in the 1870s. Since a seminal review published a quarter of a century ago, research in many fields has greatly advanced our understanding of the many coupled processes operating in and on the hydrothermal system. Specific advances include more refined geophysical images of the magmatic system, better constraints on the time scale of magmatic processes, characterization of fluid sources and water-rock interactions, quantitative estimates of heat and magmatic volatile fluxes, discovering and quantifying the role of thermophile microorganisms in the geochemical cycle, defining the chronology of hydrothermal explosions and their relation to glacial cycles, defining possible links between hydrothermal activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive hydrothermal activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review.

  19. Cuerpos intrusivos asociados a las mineralizaciones polimetálicas del depósito Cerro León, área del anticlinal El Tranquilo, Santa Cruz: evidencias geofísicas Intrusive bodies associated with the polymetallic mineralization of the Cerro León deposit, area of Cerro Tranquilo anticline, Santa Cruz: Geophysical evidence

    OpenAIRE

    G. A Peñalva; S. M. Jovic; C. J. Chernicoff; D.M. Guido; I. Schalamuk

    2008-01-01

    Las características geológicas tales como presencia de cuerpos intrusivos y subvolcánicos someros básicos a intermedios y de las mineralizaciones con alto contenido de sulfuros del área del anticlinal El Tranquilo, son particulares y poco representadas en el macizo del Deseado. El depósito polimetálico vetiforme Cerro León presenta una signatura geoquímica-mineralógica que lo diferencia del clásico modelo epitermal de baja sulfuración característico del macizo del Deseado. Los datos aeromagné...

  20. Nitrogen-doped hydrothermal carbons

    Energy Technology Data Exchange (ETDEWEB)

    Titirici, Maria-Magdalena; White, Robin J. [Max-Planck-Institute of Colloids and Interfaces, Potsdam (Germany). Dept. of Colloid Chemistry; Zhao, Li [Max-Planck-Institute of Colloids and Interfaces, Potsdam (Germany). Dept. of Colloid Chemistry; National Center for Nanoscience and Technology, Beijing (China)

    2012-07-01

    Nitrogen doped carbon materials are now playing an important role in cutting edge innovations for energy conversion and storage technologies such as supercapacitors and proton exchange membrane fuel cells as well as in catalytic applications, adsorption and CO{sub 2} capture. The production of such materials using benign aqueous based processes, mild temperatures and renewable precursors is of great promise in addressing growing environmental concerns for cleaner power sources at a time of increasing global demand for energy. In this perspective, we show that nitrogen doped carbons prepared using sustainable processes such as ''Hydrothermal Carbonisation'' has advantages in many applications over the conventional carbons. We also summarize an array of synthetic strategies used to create such nitrogen doped carbons, and discuss the application of these novel materials. (orig.)

  1. Analisis neotectónico del área Cerro Salinas, departamento Sarmiento, provincia de San Juan Neotectonic analysis of the Cerro Salinas area, Sarmiento department, province of San Juan

    Directory of Open Access Journals (Sweden)

    Héctor Cisneros

    2010-12-01

    Full Text Available El cerro Salinas es una de las exposiciones más australes del basamento cristalino de las Sierras Pampeanas. Alrededor del mismo han sido reconocidos varios trazos de fallas caracterizados por escarpas rectilíneas de dirección submeridiana, que afectan a depósitos sedimentarios referidos al Terciario y Cuaternario. La actitud espacial de las fallas neotectónicas está controlada por la posición de la estratificación y de los contactos litológicos principales de las unidades terciarias, lo cual se ha interpretado preliminarmente como evidencia del flexodeslizamiento asociado al acortamiento andino. Esta situación guarda mucha similitud con el estilo de deformación de las principales zonas de fallamiento cuaternario de la Precordillera Oriental. Acorde con la distribución espacial de las deformaciones neotectónicas y de la geometría de las mismas, se dividió al área analizada en tres sectores. La principal estructura neotectónica, la falla Cerro Salinas, constituye el límite oeste tanto del cerro Salinas como de los afloramientos precuaternarios circundantes con una longitud reconocida de 15,77 km. Las observaciones realizadas en el área de estudio, principalmente al norte del mismo permiten indicar que la deformación en el frente de falla está vinculada a escarpas asociadas con fallas inversas propagantes. La discriminación cronológica de las unidades morfoestratigráficas cuaternarias se realizó en base a datos de multiparámetros y a la signatura de las superficies aluviales en imágenes Landsat ETM+ y ASTER, mediante procesamiento en base al método de componentes principales. En base a la sumatoria del desplazamiento vertical desarrollado por las escarpas de falla para el Pleistoceno tardío, se ha estimado una tasa de levantamiento mínima de 0,13 mm/año.The so called Cerro Salinas is one of the southernmost expressions of the Sierras Pampeanas crystalline basement. Several fault traces with N-S-trending rectilinear

  2. Seawater bicarbonate removal during hydrothermal circulation

    Science.gov (United States)

    Proskurowski, G. K.; Seewald, J.; Sylva, S. P.; Reeves, E.; Lilley, M. D.

    2013-12-01

    High temperature fluids sampled at hydrothermal vents represent a complex alteration product of water-rock reactions on a multi-component mixture of source fluids. Sources to high-temperature hydrothermal samples include the 'original' seawater present in the recharge limb of circulation, magmatically influenced fluids added at depth as well as any seawater entrained during sampling. High-temperature hydrothermal fluids are typically enriched in magmatic volatiles, with CO2 the dominant species, characterized by concentrations of 10's-100's of mmol/kg (1, 2). Typically, the high concentration of CO2 relative to background seawater bicarbonate concentrations (~2.3 mmol/kg) obscures a full analysis of the fate of seawater bicarbonate during high-temperature hydrothermal circulation. Here we present data from a suite of samples collected over the past 15 years from high-temperature hydrothermal vents at 9N, Endeavour, Lau Basin, and the MAR that have endmember CO2 concentrations less than 10 mmol/kg. Using stable and radiocarbon isotope measurements these samples provide a unique opportunity to examine the balance between 'original' seawater bicarbonate and CO2 added from magmatic sources. Multiple lines of evidence from multiple hydrothermal settings consistently points to the removal of ~80% of the 'original' 2.3 mmol/kg seawater bicarbonate. Assuming that this removal occurs in the low-temperature, 'recharge' limb of hydrothermal circulation, this removal process is widely occurring and has important contributions to the global carbon cycle over geologic time. 1. Lilley MD, Butterfield DA, Lupton JE, & Olson EJ (2003) Magmatic events can produce rapid changes in hydrothermal vent chemistry. Nature 422(6934):878-881. 2. Seewald J, Cruse A, & Saccocia P (2003) Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: temporal variability following earthquake activity. Earth and Planetary Science Letters 216(4):575-590.

  3. Importaciones áticas del siglo V a.C. del Cerro del Prado (Algeciras, Cádiz

    Directory of Open Access Journals (Sweden)

    Cabrera, Paloma

    1996-12-01

    Full Text Available In this paper we analyze a group of Attic imports, found in the excavations of Cerro del Prado, a settlement situated in the Bahía de Algeciras (Cádiz. The great interest of this group lies in the fact that it belongs to a particular chronological period, the last third of the 5th century B.C., as we have not found later imports, and in the almost exclusive presence of black glazed vases, which gives US an idea of a very definitive demand of the punic society of the Iberian Peninsula regarding the trade of greek goods.

    Presentamos en este trabajo un conjunto de importaciones áticas halladas en las excavaciones del Cerro del Prado, situado en la bahía de Algeciras (Cádiz. El interés de este conjunto reside en su pertenencia a un momento cronológico muy concreto: el último tercio del siglo V a.C., no habiéndose hallado importaciones más modernas y en la presencia absoluta de vasos de barniz negro, lo que nos habla de una demanda muy determinada de la sociedad púnica peninsular frente al comercio de productos griegos.

  4. Storm Water Quality in Los Alamos Canyon following the Cerro Grande Fire

    Energy Technology Data Exchange (ETDEWEB)

    M. Johansen; B. Enz; B. Gallaher; K. Mullen; D. Kraig

    2001-04-01

    In May 2000, the Cerro Grande Fire burned about 7400 acres of forest on the Los Alamos National Laboratory (LANL) and about 10,000 acres in watersheds above LANL on Santa Fe National Forest lands. The resulting burned landscapes raised concerns of increased storm water runoff and transport of contaminants by runoff in the canyons traversing LANL. On June 2 and 3, 2000, rain fell in the Los Alamos Canyon watershed generating storm water runoff in the canyon bottom. This event was important in that it was the first significant runoff on LANL following the fire and occurred in a canyon containing known legacy waste sites. Samples from this runoff were analyzed for radionuclide, metal, inorganic, and organic constituents. Results show radionuclide concentrations at or below previous (pre-fire) maximum levels at locations on LANL and downstream. However, greater concentrations of some fallout-associated radionuclides (cesium-137 and strontium-90) were seen arriving on LANL from upstream areas compared to pre-fire conditions. Tests indicate most of the radionuclides in the samples were bound to sediments, not dissolved in water. Most radionuclide concentrations in sediments were below LANL Screening Action Levels, with cesium-137 and strontium-90 as exceptions. Most radionuclide concentrations in samples taken at LANL's downstream boundary were greater than those taken upstream, indicating the presence of contributing sources on LANL. For comparison purposes, doses were calculated on a mrem per liter of unfiltered water basis for 11 radionuclides commonly associated with atmospheric fallout and with LANL operations. The maximum dose was 0.094 mrem per liter unfiltered water and was largely associated with plutonium-239/240. In contrast, all filtered samples had total doses less than 0.001 mrem per liter. Compared to past data, potential doses were not increased by the fire during this initial runoff event. Of the 25 metals tested for, seven were above pre

  5. Analysis and simulatin of rock avalanche sequence in the Cerro Caquilluco landslide (Tacna, Peru)

    Science.gov (United States)

    Crosta, Giovanni B.; Frattini, Paolo; Valbuzzi, Elena; Hermanns, Reginald L.

    2014-05-01

    The Cerro Caquilluco (Tacna, Peru) rock avalanche complex has a total volume of about 15 km3 and a length of 43 km, extending from 3900 m a.s.l to 530 m a.s.l.. Based on geomorphological interpretation and lithological evidences, we reconstructed a possible rock-avalanches sequence consisting of at least nine major events. For each event, we calculated the mobilized volumes through the comparison of pre- and post-failure morphology. We argue that the first rock avalanche event corresponds to the Cerrillos Negros rock avalanche, characterized by a distal tongue shaped lobe, 11 km long, 3 km wide and 25 to 60 m thick (rough volume estimate 1.15 km3), deposited along the piedmont surface (average slope: 2° ). The reconstruction of pristine pre-failure morphology was accomplished by mimicking the preserved morphology close to the source area, and by removing the deposited volumes from the rock avalanche path. For this, we made the hypothesis that the old paleosurface was already eroded by valleys progressively moving upstream during a wetter climate, as suggested by Hoke et al (2007) for similar conditions in northern Chile. The reconstruction of the pre-event morphology required several attempts to fit the eroded and the deposited volumes. Finally, a total mobilized volume of about 10.2 km2 was obtained for this event. For the successive scenarios of slide retrogression, we used the morphologies obtained by previous scenarios as pre-failure morphologies, and we calculated, by difference with current topography, the lobe volumes. The volumes of single rock avalanche episodes decrease from the first to the last event, roughly following a power-law decay. This behavior is comparable to that described by Utili and Crosta (2011) for retrogressive instabilities in rocky cliffs. The rock-avalanche events have been simulated, to verify the different scenarios in terms of spreading area and maximum runout, by using SPH (Smooth Particle Hydrodynamics) and Finite Element codes

  6. El megadeslizamiento del cerro Uritorco, ladera occidental de la Sierra chica de Córdoba

    Directory of Open Access Journals (Sweden)

    Claudio A Carignano

    2014-03-01

    Full Text Available En el extremo norte de la Sierra Chica de Córdoba, sobre el flanco oeste del cerro Uritorco (1.949 m s.n.m., se ha identificado un megadeslizamiento (30°49'55,46"S y 64°29'50,31"O. Los materiales movilizados del frente del escarpe de la falla Sierra Chica, han cubierto parcialmente el granito de Capilla del Monte y los abanicos aluviales pleistocenos del piedemonte. El lóbulo y bloques rotados del deslizamiento conforman un alto topográfico que oficia de límite entre los valles de Punilla (al sur y de Charbonier (al noroeste. Mediante técnicas de procesamiento e interpretación de imágenes satelitales multiespectrales de media (Landsat-ETM y muy alta resolución (GeoEye-1, análisis digital del terreno a partir de modelos de elevación (SRTM y Aster-GDEM y el correspondiente control de campo, se ha delimitado y caracterizado esta megageoforma nunca antes advertida. Dada la elevada sismicidad actual e histórica de la zona y los indicios morfotectónicos que señalan como activas a las fallas Sierra Chica y Pajarillo-Copacabana-Masa, se estima que este deslizamiento posiblemente fue gatillado por un evento sísmico, acontecido en alguna de esas estructuras. Tanto el depósito del deslizamiento como su cicatriz de despegue presentan un significativo grado de erosión hídrica. Por análisis comparativos con otros deslizamientos ya datados y de características similares, situados en el escarpe occidental de las Sierras de San Luis, se le asigna una edad pleistocena medio-tardía. Por su volumen y características (2,1 x109 m³ se estableció que se trata de un megadeslizamiento único en las Sierras de Córdoba y constituye uno de los deslizamientos de mayor tamaño entre los registrados hasta el presente en Argentina.

  7. The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats: Complex Seafloor Expressions of Subsurface Hydrothermal Circulation

    OpenAIRE

    Teske, Andreas; de Beer, Dirk; McKay, Luke J.; Margaret K. Tivey; Biddle, Jennifer F.; Hoer, Daniel; Lloyd, Karen G.; Lever, Mark A.; Røy, Hans; Albert, Daniel B.; Mendlovitz, Howard P.; MacGregor, Barbara J.

    2016-01-01

    The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediment...

  8. Chemical environments of submarine hydrothermal systems

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to approximately 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such

  9. The aggressiveness of the geothermal steam controlled; La agresividad del vapor geotermico controlada

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, Sergio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    The first two units of Cerro Prieto have generated electric energy since 1973; in 1988 completed 15 years of continuous operation, without corrosion problems in the turbines in spite of the utilization of geothermal steam. The experience and the good results obtained during the first years of operation of these two units of 37.5 MW each, were of great help for the Cerro Prieto extension, having as of this date an installed capacity of 620 MW. [Espanol] Las dos primeras unidades de Cerro Prieto han generado energia electrica desde 1973; cumplieron 15 anos de operacion continua en 1988, sin problemas de corrosion en las turbinas a pesar del uso de vapor geotermico. La experiencia y los buenos resultados obtenidos durante los primeros anos de operacion de estas dos unidades de 37.5 MW cada una fueron de gran apoyo para la aplicacion de Cerro Prieto, teniendose a la fecha 620 MW de capacidad instalada.

  10. Hydrothermal plumes and processes in Indian Ocean

    OpenAIRE

    Sands, Carla Marie

    2006-01-01

    The predicted cycling of the whole ocean through hydrothermal plumes is comparable to the mixing time of the oceans (few thousand years). Hence, understanding hydrothermal plume processes is crucial if their impact on the global geochemical cycles of elements is to be assessed. One of the most important processes that has been demonstrated to modify the gross chemical flux from venting to the oceans is the oxidative precipitation of dissolved Fe (II). It has been hypothesised t...

  11. Hydrothermal industrialization: direct heat development. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-05-01

    A description of hydrothermal resources suitable for direct applications, their associated temperatures, geographic distribution and developable capacity are given. An overview of the hydrothermal direct-heat development infrastructure is presented. Development activity is highlighted by examining known and planned geothermal direct-use applications. Underlying assumptions and results for three studies conducted to determine direct-use market penetration of geothermal energy are discussed.

  12. 40Ar/39Ar geochronology and palynology of the Cerro Negro formation, South Shetland Islands, Antarctica: a new radiometric tie for cretaceous terrestrial biostratigraphy in the southern hemisphere

    International Nuclear Information System (INIS)

    The upper part of the Jurassic-Cretaceous Byers Group, exposed on Byers Peninsula in the South Shetland Islands, Antarctica, consists of 1.4 km of non-marine strata assigned to the Cerro Negro Formation. Silicic pyroclastic units close to the base of the formation have yielded new 40Ar/39Ar ages of 120.3 ± 2.2 Ma on plagioclase from one horizon, and 119.4 ± 0.6 and 119.1± 0.8 Ma on biotite and plagioclase from a second horizon. Plagioclase from a welded ignimbrite close to the topmost exposed part of the formation has given an 40Ar/39Ar age of 119 ± 3.0 Ma. These ages indicate that the Cerro Negro Formation was deposited during a relatively short period in early Aptian times. The identification of palynomorph taxa has enabled us to propose correlations for the Cerro Negro Formation with spore/pollen zonations of South America and Australia. The presence of Interulobites pseudoreticulatus, Appendicisporites and F. wonthaggiensis in the Cerro Negro Formation supports correlation with the Interulobites-Foraminisporis and the lower part of the tectifera-corrugatus zones in southern South America. The presence of Foraminisporis asymmetricus and other palynomorphs suggests correlation with the Cyclosporites hughesii Interval Zone of early to late Aptian age in Australia. These data represent a valuable addition to the few radiometric ties available for Mesozoic terrestrial palyno-stratigraphy in the Southern Hemisphere. Copyright (1999) Blackwell Science Pty Ltd

  13. El frente de corrimiento andino al nivel de los cerros Penitentes y Visera (alta Cordillera de Mendoza: aspectos cronológicos y cartográficos

    Directory of Open Access Journals (Sweden)

    Jean-Claude Vicente

    2009-10-01

    Full Text Available El hallazgo de una iportante fauna de invertebrados marinos del Tithoniano superior a espaldas del cerro Penitentes en la secuencia carbonática basal de la primera escama del frente de corrimiento andino, confirma la lógica tectónica de un despegue de esta unidad a nivel del Yeso Principal y lleva a invalidar ciertas correlaciones litoestratigráficas y bosquejos paleogeográficos asignados a la Formación La Manga. Por otro lado, el análisis de algunos perfiles claves en torno al cerro Penitentes entre la quebrada Vargas y el cerro Visera permite presentar una reinterpretación tectónica del sector. Esta se sustenta en el reconocimiento y la diferenciación de las unidades terciarias básicas representadas por los Conglomerados Penitentes (Mioceno inferior y los Aglomerados Santa María (Mioceno superior en una relación muy similar a la descrita anteriormente al norte de Puente del Inca. El estudio permite seguir las interferencias, en un contexto polifásico, entre las reactivaciones del corrimiento Penitentes de piel fina y un cabalgamiento frontal de piel gruesa que repite la secuencia terciaria. La discordancia entre las secuencias terciarias y el emplazamiento de una klippe de Malm sobre los Conglomerados Penitentes del sinclinal del cerro Visera, conduce a otorgar cierta importancia a la fase del final del Mioceno inferior.

  14. A re-appraisal of the stratigraphy and volcanology of the Cerro Galán volcanic system, NW Argentina

    Science.gov (United States)

    Folkes, Christopher B.; Wright, Heather M.; Cas, Ray A.F.; de Silva, Shanaka L.; Lesti, Chiara; Viramonte, Jose G.

    2011-01-01

    From detailed fieldwork and biotite 40Ar/39Ar dating correlated with paleomagnetic analyses of lithic clasts, we present a revision of the stratigraphy, areal extent and volume estimates of ignimbrites in the Cerro Galán volcanic complex. We find evidence for nine distinct outflow ignimbrites, including two newly identified ignimbrites in the Toconquis Group (the Pitas and Vega Ignimbrites). Toconquis Group Ignimbrites (~5.60–4.51 Ma biotite ages) have been discovered to the southwest and north of the caldera, increasing their spatial extents from previous estimates. Previously thought to be contemporaneous, we distinguish the Real Grande Ignimbrite (4.68 ± 0.07 Ma biotite age) from the Cueva Negra Ignimbrite (3.77 ± 0.08 Ma biotite age). The form and collapse processes of the Cerro Galán caldera are also reassessed. Based on re-interpretation of the margins of the caldera, we find evidence for a fault-bounded trapdoor collapse hinged along a regional N-S fault on the eastern side of the caldera and accommodated on a N-S fault on the western caldera margin. The collapsed area defines a roughly isosceles trapezoid shape elongated E-W and with maximum dimensions 27 × 16 km. The Cerro Galán Ignimbrite (CGI; 2.08 ± 0.02 Ma sanidine age) outflow sheet extends to 40 km in all directions from the inferred structural margins, with a maximum runout distance of ~80 km to the north of the caldera. New deposit volume estimates confirm an increase in eruptive volume through time, wherein the Toconquis Group Ignimbrites increase in volume from the ~10 km3 Lower Merihuaca Ignimbrite to a maximum of ~390 km3 (Dense Rock Equivalent; DRE) with the Real Grande Ignimbrite. The climactic CGI has a revised volume of ~630 km3 (DRE), approximately two thirds of the commonly quoted value.

  15. Analisis neotectónico del área Cerro Salinas, departamento Sarmiento, provincia de San Juan

    Directory of Open Access Journals (Sweden)

    Héctor Cisneros

    2010-12-01

    Full Text Available El cerro Salinas es una de las exposiciones más australes del basamento cristalino de las Sierras Pampeanas. Alrededor del mismo han sido reconocidos varios trazos de fallas caracterizados por escarpas rectilíneas de dirección submeridiana, que afectan a depósitos sedimentarios referidos al Terciario y Cuaternario. La actitud espacial de las fallas neotectónicas está controlada por la posición de la estratificación y de los contactos litológicos principales de las unidades terciarias, lo cual se ha interpretado preliminarmente como evidencia del flexodeslizamiento asociado al acortamiento andino. Esta situación guarda mucha similitud con el estilo de deformación de las principales zonas de fallamiento cuaternario de la Precordillera Oriental. Acorde con la distribución espacial de las deformaciones neotectónicas y de la geometría de las mismas, se dividió al área analizada en tres sectores. La principal estructura neotectónica, la falla Cerro Salinas, constituye el límite oeste tanto del cerro Salinas como de los afloramientos precuaternarios circundantes con una longitud reconocida de 15,77 km. Las observaciones realizadas en el área de estudio, principalmente al norte del mismo permiten indicar que la deformación en el frente de falla está vinculada a escarpas asociadas con fallas inversas propagantes. La discriminación cronológica de las unidades morfoestratigráficas cuaternarias se realizó en base a datos de multiparámetros y a la signatura de las superficies aluviales en imágenes Landsat ETM+ y ASTER, mediante procesamiento en base al método de componentes principales. En base a la sumatoria del desplazamiento vertical desarrollado por las escarpas de falla para el Pleistoceno tardío, se ha estimado una tasa de levantamiento mínima de 0,13 mm/año.

  16. Los granitos peraluminosos de las Sierras de Vinquis, Cerro Negro y Zapata (Sierras Pampeanas, provincia de Catamarca, Argentina

    Directory of Open Access Journals (Sweden)

    Medina, M. E.

    1992-12-01

    Full Text Available The studied plutons are close to several batholiths of this region, as Sierra de Mazán and other, but with some mineralogical peculiarities. The magmatic cordierite, common in proximate places, is scarce, as sillimanite, while the andalusite is very rare, with few tourmaline. Fluorite and allanite are also typical accasories only in the granites of the Sierra de Zapata. All plutons are peraluminous of potassic tendency, with cortical affinity.The interpretation of the geochemical values distinguishes between granites of different maturity, emplaced under a predominant influence of active margin for Cerro Negro and Vinquis, while the batholith of Zapata has, below these concepts, a marked feature of within plate.The mineralogical associations suggest that the granites of Cerro Negro and Vinquis were emplaced to pressures of 2 kb or less and temperature of 650º C, while the granites of Zapata had done under conditions of lesser pressure, between 1.5 and 2.0 kb and lower temperature, 600-650º C.A grandes rasgos, los plutones estudiados tienen semejanzas con otros del entorno regional, tal como los de la Sierra de Mazán, pero con peculiaridades mineralógicas. La cordierita magmática, que en lugares próximos es muy abundante, es aquí escasa, al igual que la sillimanita, mientras que la andalucita es muy rara y la turmalina poco frecuente. La fluorita y allanita son accesorios comunes y de cierta abundancia sólo en los granitos de la Sierra de Zapata.Todos los plutones son peralumínicos y de tendencia potásica, con neta afinidad cortical. El estudio estadístico de datos geoquímicos seleccionados, permite diferenciar agrupaciones que tienen un reflejo satisfactorio en los plutones caracterizados, por encima de las variaciones de facies. La interpretación de los valores geoquímicos distingue granitos de desigual madurez, emplazados bajo una influencia predominante de margen activo o intraplaca de características continentales, en

  17. Chatkalita, nekrasovita y otros minerales del grupo de la estannita de Veta María Eugenia, Cerro Atajo, Catamarca Chatkalita, nekrasovita y otros minerales del grupo de la estannita de veta María Eugenia, Cerro Atajo, Catamarca

    OpenAIRE

    M. F. Márquez-Zavalía; M. A. Galliski

    2007-01-01

    En veta María Eugenia, Cerro Atajo, Catamarca, se encontró una asociación de minerales de estaño integrada por: chatkalita Cu6Fe2+Sn2S8, nekrasovita Cu26V2(Sn,As,Sb)6S32, colusita Cu26V2(As,Sn,Sb)6S32, kësterita Cu2(Zn,Fe)SnS4 y estannoidita Cu8(Fe,Zn)3Sn2S12. Estos minerales, incluidos en watanabeíta, están acompañados principalmente por pirita, esfalerita, calcopirita, tetraedrita, bornita y galena; aikinita, enargita, luzonita, marcasita, arsenopirita y pirrotina participan como minerales ...

  18. Eruptive history of the youngest Mexican Shield and Mexico's most voluminous Holocene eruption: Cerro El Metate

    Science.gov (United States)

    Oryaëlle Chevrel, Magdalena; Guilbaud, Marie-Noelle; Siebe, Claus

    2016-04-01

    Small to medium-sized shield volcanoes are an important component of many volcanic fields on Earth. The Trans-Mexican Volcanic Belt, one of the most complex and active continental arcs worldwide, displays a large number of such medium-sized volcanoes. In particular the Michoacán-Guanajuato Volcanic Field (MGVF) situated in central Mexico, is the largest monogenetic volcanic field in the world and includes more than 1000 scoria cones and about four hundred medium-sized volcanoes, also known as Mexican shields. The Mexican shields nevertheless represent nearly 70% of the total volume erupted since 1 Ma and hence played a considerable role in the formation of the MGVF. However, the source, storage, and transport as well as the physical properties (density, viscosity, volatile content, etc.) of the magmas involved in these eruptions remain poorly constrained. Here, we focus on Cerro El Metate, the youngest monogenetic andesite shield volcano of the field. New C14 dates for the eruption yield a young age (~AD 1250), which briefly precedes the initial rise of the Tarascan Empire (AD 1350-1521) in this region. This volcano has a minimum volume of ~9.2 km3 DRE, and its viscous lava flows were emplaced during a single eruption over a period of ~35 years covering an area of 103 km2. By volume, this is certainly the largest eruption during the Holocene in Mexico, and it is the largest andesitic effusive eruption known worldwide for this period. Such a large volume of lava erupted in a relatively short time had a significant impact on the environment (modification of the hydrological network, forest fires, etc.), and hence, nearby human populations probably had to migrate. Its eruptive history was reconstructed through detailed mapping, and geochemical and rheological analyses of its thick hornblende-bearing andesitic flows. Early and late flows have distinct morphologies, chemical and mineralogical compositions, and isotopic signatures which show that these lavas were fed by

  19. Evaluation of the Cerro Solo nuclear ore, province of Chubut. On the economic parameters of the deposit. Pt. 3

    International Nuclear Information System (INIS)

    Preliminary results of the resources estimation carried out in the Cerro Solo uranium ore deposit, located in the Chubut Province, 1900 km SW from Buenos Aires and 380 Km W from Trelew, presented in tonnes of uranium recoverable at costs up to U$S 80/kgU, are as follows: a) Reasonable assured resources (indicated): 800 tU; b) Estimates Additional Resources (inferred): 2200 tU. Economic evaluation at the order-of-magnitude level, performed using the grade-tonnage model of the deposit, resulted a useful tool in the different stages of the project to identify the influence of technical parameters on the potential profitability. Research about feasibility of in-situ leaching method of exploitation for this deposit introduces an interesting alternative for future uranium production in the country. (Author)

  20. IMPACT OF ADDITIONALS CONTAMINANTS DUE TO ACID MINE DRAINAGE IN TRIBUTARIES OF THE PILCOMAYO RIVER FROM CERRO RICO, POTOSÍ, BOLIVIA

    Directory of Open Access Journals (Sweden)

    William H.J. Strosnider

    2014-09-01

    Full Text Available Intensive mining and processing of the polymetallic sulfide ore body of Cerro Rico de Potosí (Bolivia has occurred since 1545. To further investigate acid mine drainage (AMD discharges and their link to downstream contamination, data were gathered during two sampling events during the most extreme periods of the dry and wet seasons of one year. Concentrations of Ag, B, Ba, Mo, Sb, Se, Sn and V in AMD and receiving streams were greater than Bolivian discharge limits and receiving water body guidelines as well as international agricultural use standards. High concentrations of rare earth metals have been documented in this area. Results indicate that contamination from mining has a larger scope than previously thought and underscore the importance of remediation.

  1. Charnockitic ortho gneisses and mafic granulites of Cerro Olivo complex, proterozoic basement of SE Uruguay, Part 1: Geology

    International Nuclear Information System (INIS)

    Charnockitic ortho gneisses and mafic granulite s exposed in the Cerro Bori Block, in the center of Punta del Este terrain, were the first document occurrence of granulitic rocks from SE sector of the Uruguayan Shield. We present here their main geological features, with the purpose to suggest some petrologic and structural interesting problems for a future lithogeochemical, mineral chemistry, stable isotopes and fluid inclusion studies about these rocks. We propose some speculation form field-based studies considering a cognate magmatic origin of both kinds of rocks, previous to a homogeneous granulitic metamorphism. Some structural evidences indicate that after their uplift, these rocks were located on over thickened crust, at great to medium deepness. A cataclasis during anatexis and amphibolite-facies mineral association stabilization are common phenomena. Other evidences suggest a polycyclic character for the regional geologic evolution

  2. Notes on the ecology of Phyllodactylus reissi (Phyllodactylidae: Sauria in Parque Nacional Cerros de Amotape (Tumbes, Peru

    Directory of Open Access Journals (Sweden)

    Juan Carlos Jordán Arizmendi

    2012-02-01

    Full Text Available Some basics aspects on the ecology of the nocturnal gecko Phyllodactylus reissi from Parque Nacional Cerros de Amotape (Tumbes, Peru are described. This species used rock boulders (57,4% and trees (31,9% as microhabitats primarily, exhibiting a nocturnal activity pattern, with a peak between 2100-2200 hours, remaining active until midnight. Body temperature (mean 24,4 ºC was correlated with both air and substrate temperature, with the last variable affecting in higher degree (47% the body temperature of this species. The slightly high body temperature of Phyllodactylus reissi, compared to other Phyllodactylus geckos, could be related to nocturnal microhabitat use and diurnal retreat site selection. More studies on lizard ecology from this endangered ecosystem are needed.

  3. Estudio de la líqueno flora encontrada en el Cerro de Quininí, Tibacuy, Cundinamarca

    Directory of Open Access Journals (Sweden)

    Hormaza Francisco

    2000-12-01

    Full Text Available

    Se realizó un muestreo de la liquen o flora del cerro de Quininí, Tibacuy, Cundinamarca para estudiar las características morfológicas externas de los géneros de líquenes encontrados en el. A su vez se hizo la revisión bibliográfica acerca de dichos géneros, datando así la riqueza de líquenes en la zona con 8 géneros en total y con respecto al papel de bioindicadores se mostró el grado de intervención para el lugar.

  4. Los marsupiales (Mammalia del Mioceno Superior de la Formación Cerro Azul (Provincia de La Pampa, Argentina

    Directory of Open Access Journals (Sweden)

    Visconti, G.

    2000-04-01

    Full Text Available We describe the most complete South American marsupial association of Huayquerian Age (late Miocene. Specimens were recovered from several new localities of central and northern La Pampa province (central Argentina, at levels assignable to Cerro Azul Fm.: Bajo Giuliani, Quehué, Telén, El Guanaco, and Laguna Chillhué. Loessoid sediments studied from this formation are indicative of lacustrine deposits overlaid by eolian levels bearing evidences of pedogenesis. A study of these levels at each one of the new localities led to their correlation in an integrated profile of Cerro Azul Fm. This formation corresponds to «Epecuén Fm.», at least in Salinas Grandes de Hidalgo, and probably also to the upper levels of Arroyo Chasicá Fm. The studied marsupials are representative of almost all major lineages (orders of South American Neogene marsupials. The marmosine didelphid Zygolestes tatei sp. nov. differs from the type species of the genus in its larger size, unreduced third lower premolar, and in the less reduction of the metaconid in the last lower molar. Another marmosine, Thylamys pinei sp. nov., differs from other Marmosini in the twinning of the para- and metaconid in the lower molars, and in the wider talonid of the m4. The Monodelphini marmosines Thylatheridium hudsoni y T. dolgopolae are abundant in several localities of this formation; their study confirms close affinities between this genus and Monodelphis. The didelphines Hyperdidelphys pattersoni and an indeterminate species of Lutreolina are also represented by a few specimens. A mandibular fragment including part of the last molar may represent the oldest record of a Sparassocynidae in central Argentina. The Borhyaenidae and Thylacosmilidae (Sparassodonta are also recorded by a few, fragmentary specimens. Pliolestes venetus sp. nov. (Paucituberculata, Caenolestidae differs from the type species of the genus in its smaller size and in the larger, less displaced metaconid in the

  5. Constraining the Paleogene of South America: Magnetostratigraphy and paleoclimate proxy records from Cerro Bayo (Provincia de Salta, Argentina)

    Science.gov (United States)

    Hyland, E.; Cotton, J. M.; Sheldon, N. D.

    2012-12-01

    Records of rapid climatic and ecological shifts in the past are crucial for understanding global systems and for predicting future impacts of climate change. Transient and broad scale hyperthermal events during the Paleogene, such as the Paleocene-Eocene Thermal Maximum (PETM) and Early Eocene Climatic Optimum (EECO), have been studied extensively through both marine records and a significant terrestrial record from North America. Despite this, little evidence exists from the climatic and ecological histories of other major landmasses, which limits the effectiveness of global climate response predictions. Here we present an integrated paleoenvironmental reconstruction of the early Paleogene from a site in central South America (Cerro Bayo, Argentina), including a new magnetostratigraphic age model, pedological and sedimentological interpretation, whole rock geochemical climate proxies, isotopic environmental proxies, and microfloral assemblages. Cerro Bayo is a 235-meter terrestrial section that exposes the Tunal, Mealla, and Maiz Gordo Formations, and based on magnetostratigraphic interpolation spans roughly 58—50 Mya, including both the PETM and EECO events. These formations are composed primarily of reddish sandstone and siltstone, much of which exhibits features characteristic of a moderate degree of pedogenesis (i.e., Inceptisols and Alfisols). High-resolution climate proxies derived from paleosol geochemical compositions highlight rapid increases in mean annual temperature (>5°C) and precipitation (>300 mm yr-1) during the PETM, as well as more gradual increasing temperature and precipitation trends leading up to the EECO. Carbon isotope stratigraphy through the section also indicates a sizable negative excursion (~4‰) during the PETM, and generally positive isotopic trends during the early Eocene. Phytolith biostratigraphy also details changes in local vegetation composition during climatic events that corresponds to similar patterns seen in terrestrial

  6. Development of the Cerro solo deposit and uranium favorability of the San Jorge Gulf Basin, province of Chubut

    International Nuclear Information System (INIS)

    In the future the uranium exploration activities of CNEA would tend to improve the knowledge of geology and uranium favorability; to perform prospection tasks, and research and development in exploration technologies, to contribute to be in a position to meet the requirements of the country in the long term. On the other hand, a strong growth of nuclear capacity is expected in the first two decades of the next century. Based on its promising grade, the Cerro Solo uranium ore deposit was selected in 1990 by the CNEA to carry out an assessment project. The intensive exploration level was accomplished, as follows: definition of general characteristics of the main orebodies; detailed geologic studies; estimation of resources with adequate data; and preliminary selection of mining-milling methods to estimate the potential profitability of the project. The deposit belongs to the sandstone type. The mineralized layers are distributed into the fluvial sandstones and conglomerates of the cretaceous Chubut Group, lying 50 to 130 m deep Resources of the deposit, with an average grade of 0.3% U, in tonnes of recoverable uranium at costs of up to $80/kg U, are: Reasonable Assured Resources (RAR): 800 t U, Estimated Additional Resources, Category I (EAR-I): 2100 t U. Follow-up drilling programmes are being performed at present in some of the target sites defined in the paleochannel that hosts the Cerro Solo deposit, in order to establish the hypothetical resources of the area. The sites were determined as a result of the exploration that CNEA conducted in the Pichinan uranium district. Recently a regional research project was formulated, for the detailed exploration in the San Jorge Gulf Basin, where the Chubut Group is distributed. 17 refs, 4 figs

  7. Sample Return from Ancient Hydrothermal Springs

    Science.gov (United States)

    Allen, Carlton C.; Oehler, Dorothy Z.

    2008-01-01

    Hydrothermal spring deposits on Mars would make excellent candidates for sample return. Molecular phylogeny suggests that that life on Earth may have arisen in hydrothermal settings [1-3], and on Mars, such settings not only would have supplied energy-rich waters in which martian life may have evolved [4-7] but also would have provided warm, liquid water to martian life forms as the climate became colder and drier [8]. Since silica, sulfates, and clays associated with hydrothermal settings are known to preserve geochemical and morphological remains of ancient terrestrial life [9-11], such settings on Mars might similarly preserve evidence of martian life. Finally, because formation of hydrothermal springs includes surface and subsurface processes, martian spring deposits would offer the potential to assess astrobiological potential and hydrological history in a variety of settings, including surface mineralized terraces, associated stream deposits, and subsurface environments where organic remains may have been well protected from oxidation. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data [12-14]. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel, and based on these new data, we have interpreted several features in Vernal Crater, Arabia Terra as ancient hydrothermal springs [15, 16].

  8. Ancient Hydrothermal Springs in Arabia Terra, Mars

    Science.gov (United States)

    Oehler, Dorothy Z.; Allen, Carlton C.

    2008-01-01

    Hydrothermal springs are important astrobiological sites for several reasons: 1) On Earth, molecular phylogeny suggests that many of the most primitive organisms are hyperthermophiles, implying that life on this planet may have arisen in hydrothermal settings; 2) on Mars, similar settings would have supplied energy- and nutrient-rich waters in which early martian life may have evolved; 3) such regions on Mars would have constituted oases of continued habitability providing warm, liquid water to primitive life forms as the planet became colder and drier; and 4) mineralization associated with hydrothermal settings could have preserved biosignatures from those martian life forms. Accordingly, if life ever developed on Mars, then hydrothermal spring deposits would be excellent localities in which to search for morphological or chemical remnants of that life. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel which allows detailed analysis of geologic structure and geomorphology. Based on these new data, we report several features in Vernal Crater, Arabia Terra that we interpret as ancient hydrothermal springs.

  9. The hydrothermal power of oceanic lithosphere

    Directory of Open Access Journals (Sweden)

    C. J. Grose

    2015-03-01

    Full Text Available We have estimated the power of ventilated hydrothermal heat transport, and its spatial distribution, using a set of recently developed plate models which highlight the effects of hydrothermal circulation and thermal insulation by oceanic crust. Testing lithospheric cooling models with these two effects, we estimate that global advective heat transport is about 6.6 TW, significantly lower than previous estimates, and that the fraction of that extracted by vigorous circulation on the ridge axes (<1 Ma is about 50% of the total, significantly higher than previous estimates. This low hydrothermal power estimate originates from the thermally insulating properties of oceanic crust in relation to the mantle. Since the crust is relatively insulating, the effective properties of the lithosphere are "crust dominated" near ridge axes (yielding lower heat flow, and gradually approach mantle values over time. Thus, cooling models with crustal insulation predict low heat flow over young seafloor, implying that the difference of modeled and measured heat flow is due to the heat transport properties of the lithosphere, in addition to ventilated hydrothermal circulation as generally accepted. These estimates may bear on important problems in the physics and chemistry of the Earth because the magnitude of hydrothermal power affects chemical exchanges between the oceans and the lithosphere, thereby affecting both thermal and chemical budgets in the oceanic crust and lithosphere, the subduction factory, and convective mantle.

  10. Cuerpos intrusivos asociados a las mineralizaciones polimetálicas del depósito Cerro León, área del anticlinal El Tranquilo, Santa Cruz: evidencias geofísicas Intrusive bodies associated with the polymetallic mineralization of the Cerro León deposit, area of Cerro Tranquilo anticline, Santa Cruz: Geophysical evidence

    Directory of Open Access Journals (Sweden)

    G. A Peñalva

    2008-03-01

    Full Text Available Las características geológicas tales como presencia de cuerpos intrusivos y subvolcánicos someros básicos a intermedios y de las mineralizaciones con alto contenido de sulfuros del área del anticlinal El Tranquilo, son particulares y poco representadas en el macizo del Deseado. El depósito polimetálico vetiforme Cerro León presenta una signatura geoquímica-mineralógica que lo diferencia del clásico modelo epitermal de baja sulfuración característico del macizo del Deseado. Los datos aeromagnéticos del área del anticlinal El Tranquilo permiten reconocer una conspicua anomalía subcircular que se interpreta como un intrusivo no aflorante, de aproximadamente 9 km de diámetro, que subyace al Grupo El Tranquilo y a la Formación Roca Blanca; su profundidad se estima en 1400 m. Este cuerpo intrusivo genera el domamiento regional del anticlinal El Tranquilo y el fracturamiento radial asociado. La interpretación de la presencia de pequeños cuerpos intrusivos y subvolcánicos o apófisis alimentados por el cuerpo intrusivo mayor, asociados con anomalías magnéticas de menor diámetro y mayor gradiente, está confirmada por datos de perforación. Las principales vetas del depósito Cerro León se ubican asociadas espacialmente con los cuerpos intrusivos y subvolcanicos someros no aflorantes. Esto, sumado al alto contenido de sulfuros y la signatura geoquímica y mineralógica de las vetas, sugiere que posiblemente estén asociadas genéticamente a los cuerpos intrusivos subyacentes y circundantes, y permite utilizar este modelo como una herramienta de prospección para este tipo de depósitos.The geologic characteristics such as presence of basic to intermediate intrusive and subvolcanic bodies, and the mineralization with high sulfide content of the El Tranquilo anticline area are peculiar and poorly represented in the Deseado Massif. The Cerro León polymetallic deposit presents a geochemical and mineralogical signature that is

  11. Hydrothermal processing of radioactive combustible waste

    Energy Technology Data Exchange (ETDEWEB)

    Worl, L.A.; Buelow, S.J.; Harradine, D.; Le, L.; Padilla, D.D.; Roberts, J.H.

    1998-09-01

    Hydrothermal processing has been demonstrated for the treatment of radioactive combustible materials for the US Department of Energy. A hydrothermal processing system was designed, built and tested for operation in a plutonium glovebox. Presented here are results from the study of the hydrothermal oxidation of plutonium and americium contaminated organic wastes. Experiments show the destruction of the organic component to CO{sub 2} and H{sub 2}O, with 30 wt.% H{sub 2}O{sub 2} as an oxidant, at 540 C and 46.2 MPa. The majority of the actinide component forms insoluble products that are easily separated by filtration. A titanium liner in the reactor and heat exchanger provide corrosion resistance for the oxidation of chlorinated organics. The treatment of solid material is accomplished by particle size reduction and the addition of a viscosity enhancing agent to generate a homogeneous pumpable mixture.

  12. The BGU/CERN solar hydrothermal reactor

    CERN Document Server

    Bertolucci, Sergio; Caspers, Fritz; Garb, Yaakov; Gross, Amit; Pauletta, Stefano

    2014-01-01

    We describe a novel solar hydrothermal reactor (SHR) under development by Ben Gurion University (BGU) and the European Organization for Nuclear Research CERN. We describe in broad terms the several novel aspects of the device and, by extension, of the niche it occupies: in particular, enabling direct off-grid conversion of a range of organic feedstocks to sterile useable (solid, liquid) fuels, nutrients, products using only solar energy and water. We then provide a brief description of the high temperature high efficiency panels that provide process heat to the hydrothermal reactor, and review the basics of hydrothermal processes and conversion taking place in this. We conclude with a description of a simulation of the pilot system that will begin operation later this year.

  13. Characterization of advanced preprocessed materials (Hydrothermal)

    Energy Technology Data Exchange (ETDEWEB)

    Rachel Emerson; Garold Gresham

    2012-09-01

    The initial hydrothermal treatment parameters did not achieve the proposed objective of this effort; the reduction of intrinsic ash in the corn stover. However, liquid fractions from the 170°C treatments was indicative that some of the elements routinely found in the ash that negatively impact the biochemical conversion processes had been removed. After reviewing other options for facilitating ash removal, sodium-citrate (chelating agent) was included in the hydrothermal treatment process, resulting in a 69% reduction in the physiological ash. These results indicated that chelation –hydrothermal treatment is one possible approach that can be utilized to reduce the overall ash content of feedstock materials and having a positive impact on conversion performance.

  14. Hydrothermal processing of radioactive combustible waste

    International Nuclear Information System (INIS)

    Hydrothermal processing has been demonstrated for the treatment of radioactive combustible materials for the US Department of Energy. A hydrothermal processing system was designed, built and tested for operation in a plutonium glovebox. Presented here are results from the study of the hydrothermal oxidation of plutonium and americium contaminated organic wastes. Experiments show the destruction of the organic component to CO2 and H2O, with 30 wt.% H2O2 as an oxidant, at 540 C and 46.2 MPa. The majority of the actinide component forms insoluble products that are easily separated by filtration. A titanium liner in the reactor and heat exchanger provide corrosion resistance for the oxidation of chlorinated organics. The treatment of solid material is accomplished by particle size reduction and the addition of a viscosity enhancing agent to generate a homogeneous pumpable mixture

  15. Decree 343/012. Is regulated the servitude established by Decree-Law 10,383, on several lines of electricity conduction -150 KV to be built in the departments of Florida, Cerro Largo, Maldonado, Flores, San Jose and Tacuarembo

    International Nuclear Information System (INIS)

    This decree regulates the establishment of electricity conduction in Florida, Cerro Largo, Maldonado, Flores, San Jose and Tacuarembo towns. These electrical lines are necessary to provide the public service by UTE

  16. Hydrothermal processing of transuranic contaminated combustible waste

    International Nuclear Information System (INIS)

    Experiments at Los Alamos National Laboratory have demonstrated the usefulness of hydrothermal processing for the disposal of a wide variety of transuranic contaminated combustible wastes. This paper provides an overview of the implementation and performance of hydrothermal treatment for concentrated salt solutions, explosives, propellants, organic solvents, halogenated solvents, and laboratory trash, such as paper and plastics. Reaction conditions vary from near ambient temperatures and pressure to over 1000degC and 100 MPa pressure. Studies involving both radioactive and non-radioactive waste simulants are discussed. (author)

  17. Hydrothermal Synthesis of Nanostructured Vanadium Oxides

    Directory of Open Access Journals (Sweden)

    Jacques Livage

    2010-08-01

    Full Text Available A wide range of vanadium oxides have been obtained via the hydrothermal treatment of aqueous V(V solutions. They exhibit a large variety of nanostructures ranging from molecular clusters to 1D and 2D layered compounds. Nanotubes are obtained via a self-rolling process while amazing morphologies such as nano-spheres, nano-flowers and even nano-urchins are formed via the self-assembling of nano-particles. This paper provides some correlation between the molecular structure of precursors in the solution and the nanostructure of the solid phases obtained by hydrothermal treatment.

  18. Biogeochemistry of hydrothermally and adjacent non-altered soils

    Science.gov (United States)

    As a field/lab project, students in the Soil Biogeochemistry class of the University of Nevada, Reno described and characterized seven pedons, developed in hydrothermally and adjacent non-hydrothermally altered andesitic parent material near Reno, NV. Hydrothermally altered soils had considerably lo...

  19. The chemistry of hydrothermal magnetite: a review

    Science.gov (United States)

    Nadoll, Patrick; Angerer, Thomas; Mauk, Jeffrey L.; French, David; Walshe, John

    2014-01-01

    Magnetite (Fe3O4) is a well-recognized petrogenetic indicator and is a common accessory mineral in many ore deposits and their host rocks. Recent years have seen an increased interest in the use of hydrothermal magnetite for provenance studies and as a pathfinder for mineral exploration. A number of studies have investigated how specific formation conditions are reflected in the composition of the respective magnetite. Two fundamental questions underlie these efforts — (i) How can the composition of igneous and, more importantly, hydrothermal magnetite be used to discriminate mineralized areas from barren host rocks, and (ii) how can this assist exploration geologists to target ore deposits at greater and greater distances from the main mineralization? Similar to igneous magnetite, the most important factors that govern compositional variations in hydrothermal magnetite are (A) temperature, (B) fluid composition — element availability, (C) oxygen and sulfur fugacity, (D) silicate and sulfide activity, (E) host rock buffering, (F) re-equilibration processes, and (G) intrinsic crystallographic controls such as ionic radius and charge balance. We discuss how specific formation conditions are reflected in the composition of magnetite and review studies that investigate the chemistry of hydrothermal and igneous magnetite from various mineral deposits and their host rocks. Furthermore, we discuss the redox-related alteration of magnetite (martitization and mushketovitization) and mineral inclusions in magnetite and their effect on chemical analyses. Our database includes published and previously unpublished magnetite minor and trace element data for magnetite from (1) banded iron formations (BIF) and related high-grade iron ore deposits in Western Australia, India, and Brazil, (2) Ag–Pb–Zn veins of the Coeur d'Alene district, United States, (3) porphyry Cu–(Au)–(Mo) deposits and associated (4) calcic and magnesian skarn deposits in the southwestern United

  20. Composición, estructura y diversidad del cerro El Águila, Michoacán, México Composition, structure and diversity of the cerro El Águila, Michoacán, Mexico

    Directory of Open Access Journals (Sweden)

    Luis Eduardo Zacarias-Eslava

    2011-09-01

    Full Text Available Se describe la composición, estructura y diversidad de la vegetación presente en el cerro El Águila, Michoacán. Se reconocieron fisonómicamente 5 tipos de vegetación y en cada uno se establecieron 16 parcelas circulares de 400 m² (3.2 ha para censar los individuos leñosos ≥ 10 cm d.a.p., con una parcela anidada de 100 m² (0.8 ha para los individuos entre 2.5 y 9.9 cm d.a.p. El muestreo incluyó 46 especies agrupadas en 33 géneros y 21 familias. Los bosques tropical caducifolio y de Quercus deserticola tuvieron los valores más bajos de altura promedio ( 11 m y área basal (> 40 m²/ha. La diversidad fue mayor en el bosque tropical caducifolio (S=23 y α =5.4 y menor en el de Quercus-Pinus (S= 13 y α= 2.71. En general, los tipos de vegetación mostraron diferentes especies dominantes y una alta diversidad beta. La composición y estructura de estas comunidades puede asociarse a cambios en altitud y a la perturbación por actividades humanas. No obstante, la zona de estudio aún presenta áreas en buen estado de conservación, particularmente los bosques templados hacia las zonas con mayor altitud, por lo que se sugiere que en un futuro cercano sea incluida dentro de alguna categoría de protección estatal.This study describes composition, structure and diversity of vegetation in the Cerro El Águila, Michoacán. Five plant communities were recognized and for each one all woody individuals ≥10 cm DBH were tallied in sixteen 400 m² circular plots, whereas individuals between 2.5 and 9.9 cm DBH were measured in a 100 m² circular sub-plot centered within each larger plot. A total of 46 species, 33 genera and 21 families were recorded. The tropical deciduous forest and Quercus deserticola forest had low values of mean plant height ( 11 m and basal area (> 40 m²/ha. Diversity was greater in the tropical deciduous forest (S= 23 and α= 5.4, respectively and lower in the oak-pine forest (S= 13 and α= 2.71. All communities displayed

  1. The rules of urban planning and administrative responsibilities in protecting to the vulnerability and risk of Cerro Tapezco in Santa Ana

    International Nuclear Information System (INIS)

    An analysis of regulation is made of land use and administrative management of the Cerro Tapezco to show that as the years have passed it has been verified that the Costa Rican law on town planning has been inadequate for current problems due to lack of updating of various scientific and technical sources also dispersion and proliferation of competences of administrative authorities. The physical setting and planning rules is identified for CerroTapezco and surrounding towns. Local actions are explored in the elaboration of improvement and reform of the regulatory plan of Santa Ana. The administrative entities and institutions with competence in the development and implementation of plans have been identified, assessing deficiencies, inconsistencies and administrative omissions in urban planning of the city of Santa Ana and recommending changes necessary for the proper application of the Costa Rican law

  2. Caracterización arqueométrica de cerámicas ibéricas de los yacimientos de Alarcos y El Cerro de las Cabezas

    OpenAIRE

    Guirao Polo, David

    2014-01-01

    En la presente Tesis Doctoral se han analizado arqueométricamente 146 fragmentos de cerámicas de época ibérica procedentes de los yacimientos del Cerro de Alarcos (Ciudad Real) y de El Cerro de las Cabezas (Valdepeñas, Ciudad Real). A partir del análisis químico-estadístico, mineralógico, térmico y microscópico, se ha identificado la existencia de grupos cerámicos, con características propias e identificativas, que deben vincularse a la producción cerámica de uno y otro poblado. El establecim...

  3. Evaluation of the Cerro Solo nuclear ore, province of Chubut. Geological characteristics of the deposit and of the basin. Pt. 2

    International Nuclear Information System (INIS)

    The Cerro Solo uranium ore deposit, is located 420 km west from Trelew city, Chubut province, in the extra-andean. The geologic environment belongs to the northwest edge portion of the intracratonic San Jorge Gulf Basin. The uraniferous district is named Pichinanes Ridge district. The mineralization lies 25 to 130 m depth, and is hosted by Los Adobes formation aged Aptian-Albian, made up by conglomerates, sandstones, coarse-sandstones and less abundant siltstones and claystones. The Cerro Solo ore deposit that belongs to the sandstone type-uranium occurrences are lenticular or tabular shaped, associated with organic material and pyrite, generally roughly parallel to the bedding (Trend-Type). The uranium minerals are uraninite and coffinite associated with organic material and pyrite, and frequently hematite, goethite, calcite, siderite and barite are observed. (Author)

  4. Effects of the Cerro Grande Fire (Smoke and Fallout Ash) on Soil Chemical Properties Within and Around Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Fresquez, P.R.; Velasquez, W.R.; Naranjo, L. Jr.

    2000-11-01

    Soil surface (0- to 2-in. depth) samples were collected from areas within and around Los Alamos National Laboratory (LANL) just after the Cerro Grande fire, analyzed for radionuclides, radioactivity, and trace elements (heavy metals), and compared to soil samples collected in 1999 from the same sites. In addition, many types of organic substances (volatile and semivolatile organic compounds, organochlorine pesticides, polychlorinated biphenyls, high explosives, and dioxin and dioxin-like compounds) were assessed in soils from LANL, perimeter, and regional sites after the fire. Results show that impacts to regional, perimeter, and on-site (mesa top) areas from smoke and fallout ash as a result of the Cerro Grande fire were minimal.

  5. Estudio petrográfico de las facies piroclásticas de la Formación Cerro Varela en el sur de la Sierra de San Luis Petrographic study of the pyroclastic facies of the Cerro Varela Formation in the south of the Sierra de San Luis

    Directory of Open Access Journals (Sweden)

    Amancay N. Martínez

    2010-11-01

    Full Text Available En la provincia de San Luis, existen tres sub-cuencas denominadas Las Salinas, Beazley y Mercedes. Estas cuencas corresponden a depocentros de rift elongados en sentido NO, que alojan rocas ígneas de edad triásica con espesores que llegan hasta los 4.000 metros. Las rocas ígneas de la Formación Cerro Varela forman parte del cerro homónimo que constituye los últimos asomos australes de la sierra de San Luis. Las riolitas triásicas que afloran en la sierra de Varela se disponen dentro de un esquema estructural extensional asociado a la formación de cuencas de tipo rift. Las unidades analizadas de la Formación Cerro Varela están compuestas por tobas cristalinas tanto de alto grado como de bajo grado de soldadura, de composición riolítica e interpretadas como depósitos originados por flujos piroclásticos. Por su litología, edad y contexto regional, las rocas de la Formación Cerro Varela integran el magmatismo gondwánico del Grupo Choiyoi de edad permotriásica de la Cordillera Frontal de Mendoza y San Juan.In the San Luis province, there are three sub-basins called Las Salinas, Beazley and Mercedes. These basins correspond to elongated rift depocenter with a NO orientation that host Triassic igneous rocks with thicknesses that reach 4,000 meters. The igneous rocks from Cerro Varela Formation, part of the homonym hill, is the last vestige of the southern Sierra San Luis. The Triassic rhyolites that crop up in the sierra de Varela, are placed within a structural pattern associated with the formation of extensional basins. Crystal tuffs of Cerro Varela are corresponds to tuffs with high and low degree of welding, of rhyolitic composition and interpreted as pyroclastic deposits. For its lithology, age and regional context, the rocks of the Cerro Varela Formation integrate the Gondwanic magmatism of Permo-Triassic age, related to the Choiyoi Group of the Cordillera Frontal of Mendoza and San Juan.

  6. The fate of lignin during hydrothermal pretreatment

    OpenAIRE

    Trajano, Heather L.; Engle, Nancy L.; Foston, Marcus; Ragauskas, Arthur J.; Tschaplinski, Timothy J; Wyman, Charles E

    2013-01-01

    Abstract Background Effective enzymatic hydrolysis of lignocellulosic biomass benefits from lignin removal, relocation, and/or modification during hydrothermal pretreatment. Phase transition, depolymerization/repolymerization, and solubility effects may all influence these lignin changes. To better understand how lignin is altered, Populus trichocarpa x P. deltoides wood samples and cellulolytic enzyme lignin (CEL) isolated from P. trichocarpa x P. de...

  7. Hydrothermal carbonization of municipal waste streams

    Science.gov (United States)

    Hydrothermal carbonization (HTC) is a novel thermal conversion process that can be used to convert municipal waste streams into sterilized, value-added hydrochar. HTC has been mostly applied and studied on a limited number of feedstocks, ranging from pure substances to slightly more complex biomass ...

  8. Hydrothermal systems and the emergence of life

    Science.gov (United States)

    Shock, E. L.

    1994-01-01

    The author reviews current thought about life originating in hyperthermophilic microorganisms. Hyperthermophiles obtain food from chemosynthesis of sulfur and have an RNA nucleotide sequence different from bacteria and eucarya. It is postulated that a hyperthermophile may be the common ancestor of all life. Current research efforts focus on the synthesis of organic compounds in hydrothermal systems.

  9. Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

    International Nuclear Information System (INIS)

    We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

  10. Moche social boundaries and settlement dynamics at Cerro Castillo (c. AD 600-1000), Nepeña Valley, Peru Volume 1

    OpenAIRE

    Rengifo, Carlos

    2014-01-01

    This dissertation explores the pre-Columbian occupation at Cerro Castillo, a coastal settlement in the Nepeña Valley, Peru. The study examines the site’s internal organisation as well as its relationship with regional cultural phenomena during its most important period of occupation (circa AD 600-1000). Characterising the Moche presence at the site is one of the main subjects of this investigation. Moche was one of the grandest civilisations that developed in the pre-Columbian ...

  11. Cerro Grande Fire Impact to Water Quality and Stream Flow near Los Alamos National Laboratory: Results of Four Years of Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    B.M. Gallaher; R.J. Koch

    2004-09-15

    In May 2000, the Cerro Grande fire burned about 7400 acres of mixed conifer forest on the Los Alamos National Laboratory (LANL), and much of the 10,000 acres of mountainside draining onto LANL was severely burned. The resulting burned landscapes raised concerns of increased storm runoff and transport of contaminants by runoff in the canyons traversing LANL. The first storms after the fire produced runoff peaks that were more than 200 times greater than prefire levels. Total runoff volume for the year 2000 increased 50% over prefire years, despite a decline in total precipitation of 13% below normal and a general decrease in the number of monsoonal thunderstorms. The majority of runoff in 2000 occurred in the canyons at LANL south of Pueblo Canyon (70%), where the highest runoff volume occurred in Water Canyon and the peak discharge occurred in Pajarito Canyon. This report describes the observed effects of the Cerro Grande fire and related environmental impacts to watersheds at and near Los Alamos National Laboratory (LANL) for the first four runoff seasons after the fire, from 2000 through 2003. Spatial and temporal trends in radiological and chemical constituents that were identified as being associated with the Cerro Grande fire and those that were identified as being associated with historic LANL discharges are evaluated with regard to impacts to the Rio Grande and area reservoirs downstream of LANL. The results of environmental sampling performed by LANL, the New Mexico Environment Department (NMED), and U.S. Geological Survey (USGS) after the Cerro Grande fire are included in the evaluation. Effects are described for storm runoff, baseflow, stream sediments, and area regional reservoir sediment.

  12. Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

    2008-10-01

    We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

  13. Report about drilling works made in 13 Anomaly de Taylor and in the N- NE of its, around Fraile Muerto (Cerro Largo district): Uranium project

    International Nuclear Information System (INIS)

    The perforations were carried out to investigate in depth denominated anomaly 13 detected during the Taylor Mission (1975) and extended the punch area of study during you are suitable DINAMIGE-BRGM (Project the present report details the activities realised in the environs Fraile Muerto (Cerro Largo district) by the command team of perforations of the uranium project. Previously and contemporarily to the executed works, prospection became geophysical ground geochemistry geology and, works. (Uranium)

  14. The Biogeochemistry of Sulfur in Hydrothermal Systems

    Science.gov (United States)

    Schulte, Mitchell; Rogers, K. L.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in hydrothermal systems. The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in hydrothermal systems. Understanding how sulfur became prevalent in biochemical processes and many biomolecules requires knowledge of the reaction properties of sulfur-bearing compounds. We have previously estimated thermodynamic data for thiols, the simplest organic sulfur compounds, at elevated temperatures and pressures. If life began in hydrothermal environments, it is especially important to understand reactions at elevated temperatures among sulfur-bearing compounds and other organic molecules essential for the origin and persistence of life. Here we examine reactions that may have formed amino acids with thiols as reaction intermediates in hypothetical early Earth hydrothermal environments. (There are two amino acids, cysteine and methionine, that contain sulfur.) Our calculations suggest that significant amounts of some amino acids were produced in early Earth hydrothermal fluids, given reasonable concentrations H2, NH3, H2S and CO. For example, preliminary results indicate that glycine activities as high as 1 mmol can be reached in these systems at 100 C. Alanine formation from propanethiol is also a favorable reaction. On the other hand, the calculated equilibrium log activities of cysteine and serine from propanethiol are -21 and -19, respectively, at 100 C. These results

  15. Anhydrite precipitation in seafloor hydrothermal systems

    Science.gov (United States)

    Theissen-Krah, Sonja; Rüpke, Lars H.

    2016-04-01

    The composition and metal concentration of hydrothermal fluids venting at the seafloor is strongly temperature-dependent and fluids above 300°C are required to transport metals to the seafloor (Hannington et al. 2010). Ore-forming hydrothermal systems and high temperature vents in general are often associated with faults and fracture zones, i.e. zones of enhanced permeabilities that act as channels for the uprising hydrothermal fluid (Heinrich & Candela, 2014). Previous numerical models (Jupp and Schultz, 2000; Andersen et al. 2015) however have shown that high permeabilities tend to decrease fluid flow temperatures due to mixing with cold seawater and the resulting high fluid fluxes that lead to short residence times of the fluid near the heat source. A possible mechanism to reduce the permeability and thereby to focus high temperature fluid flow are mineral precipitation reactions that clog the pore space. Anhydrite for example precipitates from seawater if it is heated to temperatures above ~150°C or due to mixing of seawater with hydrothermal fluids that usually have high Calcium concentrations. We have implemented anhydrite reactions (precipitation and dissolution) in our finite element numerical models of hydrothermal circulation. The initial results show that the precipitation of anhydrite efficiently alters the permeability field, which affects the hydrothermal flow field as well as the resulting vent temperatures. C. Andersen et al. (2015), Fault geometry and permeability contrast control vent temperatures at the Logatchev 1 hydrothermal field, Mid-Atlantic Ridge, Geology, 43(1), 51-54. M. D. Hannington et al. (2010), Modern Sea-Floor Massive Sulfides and Base Metal Resources: Toward an Estimate of Global Sea-Floor Massive Sulfide Potential, in The Challenge of Finding New Mineral Resources: Global Metallogeny, Innovative Exploration, and New Discoveries, edited by R. J. Goldfarb, E. E. Marsh and T. Monecke, pp. 317-338, Society of Economic Geologists

  16. Evaluación integral del riesgo volcánico del Cerro Machín, Colombia

    Directory of Open Access Journals (Sweden)

    Leonel Vega Mora

    2013-01-01

    Full Text Available El volcán Cerro Machín (VCM se encuentra situado en la Cordillera Central de Colombia. Por la com- posición química, magnitud y extensión de sus erupciones pasadas, se reconoce como un volcán explosivo de gran potencial de daño, cuya actividad futura podría afectar intensamente durante mucho tiempo (meses hasta años una región muy estratégica para la economía del país, que cubre áreas pertenecientes a los departamentos de Tolima, Quindío, Valle del Cauca y Cundinamarca, en las cuales habitan cerca de un millón de personas. En este artículo se muestra la metodología y resultados del estudio de “Evaluación Integral del Riesgo del Cerro Machín – Colombia”, realizado durante 2009 por el Grupo PIGA de Investigación en Política, Información y Gestión Ambiental de la Facultad de Ingeniería de la Universidad Nacional de Colombia, tomando como punto de partida el estudio de “Evaluación de la Amenaza Volcánica Potencial del Cerro Machín” adelantado en el 2002 por el Servicio Geológico Colombiano (SGC. En consecuencia, se genera y ajusta una nueva ecuación para la determinación del riesgo, basada en la valoración de índices de amenaza intrínseca e índices de vulnerabilidad, los primeros en función del grado de intensidad, duración, extensión y acumulación de las amenazas, y los segundos, en función del grado de exposición espacial y temporal de los elementos (sociales, económicos, institucionales y ecosisté- micos y de su capacidad de respuesta intrínseca y extrínseca ante las amenazas. Con estas ecuaciones y mediante el uso de sistemas de información geográfica (SIG, se realiza para cada escenario de análisis considerando la modelación geoespacial del riesgo a nivel de cada pixel cartográfico del área territorial de estudio. En esta modelación se integra toda la informa- ción territorial del área en estudio, lo que permite obtener, de acuerdo con el marco lógico de evaluación preestablecido

  17. Análisis litoestratigráfico de la Formación Cerro Azul (Mioceno Superior en la provincia de La Pampa

    Directory of Open Access Journals (Sweden)

    Graciela Visconti

    2010-10-01

    Full Text Available La Formación Cerro Azul fue definida en 1980 para incluir a las sedimentitas continentales pliocenas (limolitas arenosas y areniscas limosas que afloran de manera discontinua en casi todo el ámbito de la provincia de La Pampa. No obstante, varias investigaciones paleontológicas realizadas a partir de la segunda mitad de la década del 80' han permitido ubicar geocronológicamente a la unidad en el intervalo 10 Ma a 5,8-5,7 Ma. El objetivo del trabajo es realizar un análisis de las características litoestratigráficas de la Formación Cerro Azul de acuerdo al Código Argentino de Estratigrafía. Se propone un lectoestratotipo para la unidad, consistente en el perfil de Algarrobo del Águila y un perfil auxiliar en cerro El Morro. También se establecieron las relaciones estratigráficas con otras formaciones. Se interpreta un paleoambiente depositacional de llanura, donde alternan depósitos de loess con numerosos paleosuelos, detectándose escasos depósitos lacustres en la base y pocos cursos fluviales.

  18. Hydrothermal synthesis map of bismuth titanates

    International Nuclear Information System (INIS)

    The hydrothermal synthesis of four bismuth titanate materials from common bismuth and titanium precursors under hydrothermal conditions is described. Reaction of NaBiO3·2H2O and anatase TiO2 in concentrated NaOH solution at 240 °C is shown to produce perovskite and sillenite phases Na0.5Bi0.5TiO3 and Bi12TiO20, depending on the ratio of metal precursors used. When KOH solution is used and a 1:1 ratio of the same precursors, a pyrochlore Bi1.43Ti2O6(OH)0.29(H2O)0.66 is formed. The use of a mixture of HNO3 and NaOH is shown to facilitate the formation of the Aurivillius-type bismuth titanate Bi4Ti3O12. The phases have been isolated separately as phase-pure powders and profile refinement of powder X-ray diffraction data allows comparisons with comparable materials reported in the literature. Analysis of Bi LIII-edge X-ray absorption near edge structure (XANES) spectra of the materials shows the oxidation state of bismuth is +3 in all of the hydrothermally derived products. - Graphical abstract: Use of NaBiO3·2H2O and TiO2 as reagents under hydrothermal conditions allows the phase-pure preparation of four crystalline bismuth titanate materials. Highlights: ► NaBiO3 and TiO2 under hydrothermal conditions allow formation of bismuth titanates. ► Synthesis of four distint phases has been mapped. ► Bi LIII-edge XANES shows Bi is reduced to oxidation state +3 in all materials. ► A new hydrated bismuth titanate pyrochlore has been isolated

  19. Voltammetric Investigation Of Hydrothermal Iron Speciation

    Directory of Open Access Journals (Sweden)

    Charlotte eKleint

    2016-05-01

    Full Text Available Hydrothermal vent fluids are highly enriched in iron (Fe compared to ambient seawater, and organic ligands may play a role in facilitating the transport of some hydrothermal Fe into the open ocean. This is important since Fe is a limiting micronutrient for primary production in large parts of the world`s surface ocean. We have investigated the concentration and speciation of Fe in several vent fluid and plume samples from the Nifonea vent field, Coriolis Troughs, New Hebrides Island Arc, South Pacific Ocean using competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE - AdCSV with salicylaldoxime (SA as the artificial ligand. Our results for total dissolved Fe (dFe in the buoyant hydrothermal plume samples showed concentrations up to 3.86 µM dFe with only a small fraction between 1.1% and 11.8% being chemically labile. Iron binding ligand concentrations ([L] were found in µM level with strong conditional stability constants up to log K[L],Fe3+ of 22.9. Within the non-buoyant hydrothermal plume above the Nifonea vent field, up to 84.7% of the available Fe is chemically labile and [L] concentrations up to 97 nM were measured. [L] was consistently in excess of Felab, indicating that all available Fe is being complexed, which in combination with high Felab values in the non-buoyant plume, signifies that a high fraction of hydrothermal dFe is potentially being transported away from the plume into the surrounding waters, contributing to the global oceanic Fe budget.

  20. Geographic Information System (GIS) Emergency Support for the May 2000 Cerro Grande Wildfire, Los Alamos, New Mexico, USA

    Energy Technology Data Exchange (ETDEWEB)

    C.R.Mynard; G.N.Keating; P.M.Rich; D.R. Bleakly

    2003-05-01

    In May 2000 the Cerro Grande wildfire swept through Los Alamos, New Mexico, burning approximately 17,400 ha (43,000 acres) and causing evacuation of Los Alamos National Laboratory (LANL) and the communities of Los Alamos and White Rock. An integral part of emergency response during the fire was the use of geographic information system (GIS) technology, which continues to be used in support of post-fire restoration and environmental monitoring. During the fire Laboratory GIS staff and volunteers from other organizations worked to produce maps and provide support for emergency managers, including at an emergency GIS facility in Santa Fe. Subsequent to the fire, Laboratory GIS teams supported the multiagency Burned Area Emergency Rehabilitation (BAER) team to provide GIS data and maps for planning mitigation efforts. The GIS teams continue to help researchers, operations personnel, and managers deal with the tremendous changes caused by the fire. Much of the work is under the auspices of the Cerro Grande Rehabilitation Project (CGRP) to promote recovery from fire damage, improve information exchange, enhance emergency management, and conduct mitigation activities. GIS efforts during the fire provided important lessons about institutional matters, working relationships, and emergency preparedness. These lessons include the importance of (1) an integrated framework for assessing natural and human hazards in a landscape context; (2) a strong GIS capability for emergency response; (3) coordinated emergency plans for GIS operations; (4) a method for employees to report their whereabouts and receive authoritative information during an evacuation; (5) GIS data that are complete, backed-up, and available during an emergency; (6) adaptation of GIS to the circumstances of the emergency; (7) better coordination in the GIS community; (8) better integration of GIS into LANL operations; and (9) a central data warehouse for data and metadata. These lessons are important for planning

  1. Estructura, composición y diversidad de la selva baja caducifolia del Cerro Verde, Nizanda (Oaxaca, México

    Directory of Open Access Journals (Sweden)

    José Antonio Gallardo Cruz

    2005-01-01

    Full Text Available En este estudio se describe la estructura, la composición florística y los patrones de diversidad de la selva baja caducifolia del Cerro Verde, localizado en Nizanda (Istmo de Tehuantepec, Oaxaca, México. En 30 parcelas de 100 m2 se censaron las plantas leñosas con DAP ≥ 1 cm (estrato alto, y en cinco subcuadros de 4 m2 dentro de cada una se censaron las plantas con DAP 30 cm (estrato bajo. Se encontraron 194 especies distribuidas en 52 familias. La riqueza de especies fue idéntica en ambos estratos (145 especies, y cada uno aportó de manera exclusiva ca. 25% de la riqueza total registrada. Leguminosae fue la familia más rica en especies (27, seguida por Asteraceae (20 y Euphorbiaceae (18. Las especies más frecuentes fueron Bursera simaruba + B. aff. cinerea (no distinguidas en el campo, Euphorbia schlechtendalii, Pilosocereus collinsii y Capparis verrucosa. La riqueza específica promedio por cuadro fue de 30 especies. Los índices basados en la riqueza y la abundancia de las especies (Berger-Parker = 0.20; Simpson = 0.09; α de Fisher = 9.47; Shannon = 2.78; equitatividad = 0.82 indican una alta diversidad y una consecuente baja dominancia en esta selva. Los valores extrapolados mostraron una densidad total (estratos alto + bajo de 23,950 ind. ha-1 (830 ind. ha-1 con DAP ≥ 10 cm, una cobertura de 446.7%, y un área basal de 53 m2 ha-1. La altura promedio del 10% de los árboles más altos fue 9.1 m. La estructura de la selva baja del Cerro Verde es semejante a la de otras comunidades vegetales del trópico seco de México y denota un buen estado de conservación. Este hecho, aunado a su particular composición florística, enfatiza la pertinencia de su conservación formal.

  2. Evidence for Hydrothermal Vents as "Biogeobatteries" (Invited)

    Science.gov (United States)

    Nielsen, M. E.; Girguis, P. R.

    2010-12-01

    Hydrothermal vents are unique systems that play an important role in oceanic biogeochemical cycles. As chemically reduced hydrothermal fluid mixes with cold oxic seawater, minerals precipitate out of solution resulting in chimney structures composed largely of metal sulfides and anhydrite. Pyrite, which is a natural semi-conductor, is the primary sulfide mineral, but other minerals within chimneys are also conductive (e.g. chalcopyrite, wurtzite, and some iron oxides). Sulfide chimneys are also known to host an extensive endolithic microbial community. Accordingly, submarine hydrothermal systems appear to be examples of biogeobatteries, wherein conductive mineral assemblages span naturally occuring redox gradients and enable anaerobic microbes to access oxygen as an oxidant via extracellular electron transfer (or EET). To test this hypothesis, we ran a series of electrochemical laboratory experiments in which pyrite was used as an anode (in a vessel flushed with hydrothermal-like fluid). When placed in continuity with a carbon fiber cathode, pyrite was found to accept and conduct electrons from both abiotic and biological processes (microbial EET). Specifically, electrical current increased 4-fold (5 nA/m2 to 20 nA/m2) in response to inoculation with a slurry prepared from a hydrothermal vent sample. Inspection of the pyrite anode with SEM revealed ubiquitous coverage by microbes. DNA was extracted from the anodes and the inoculum, and was subjected to pyrosequencing to examine prokaryotic diversity. These data suggest that key microbial phylotypes were enriched upon the pyrite, implicating them in EET. In addition, we deployed an in situ experiment based on microbial fuel cell architecture with a graphite anode inserted into a vent wall coupled to a carbon fiber cathode outside the vent. We observed current production over the course of one year, implying microbial EET in situ. Via pyrosequencing, we observed that the microbial community on the anode was

  3. Pyrite Recrystallization Experiments With Circulating Hydrothermal Solution

    Science.gov (United States)

    Isobe, H.; Abe, A.; Tanaka, K.

    2007-12-01

    Pyrite is one of the most common sulfide minerals found in hydrothermal deposits and sea-floor sediments from hydrothermal fumaroles. Hydrothermal fluid flow plays an important role in crystallization of sulfide minerals. In this study, we tried to reproduce pyrite crystallization with one-way flowing hydrothermal fluid. We designed a circuit circulating hydrothermal fluid by thermal convection. A rectangular circuit (42.6 cm by 17.3 cm) of SUS316 pressure tubes with 5 mm in inner diameter was used as a reaction vessel. In the circuit, pyrite dissolves to acidic fluid in upstream region. Then, pyrite will crystallize again in downstream region as temperature decreases. The rectangular plane was held to be 20 degrees inclination to generate thermal convection. One of the long sides of the rectangular was heated by an electric furnace. Starting materials were put in a tube to be heated. Upper half, approximately 20 cm, of the tube was filled with quartz sand. Next quarter was filled with equivalent mass mixture of quartz sand and powdered pyrite crystals. The lowest quarter was filled with mixture of quartz sand, pyrite, anhydrite and sulfur, those mass are equivalent. The solution was a mixture of 0.5mol/l HCl and 3.0mol/l NaCl. Maximum temperature was controlled to approximately 350°C at the center of the heated tube. Experimental durations were up to 9 days. Fluid pressure increased to approximately 6 MPa as heating. After the experiments, the run products were fixed with resin in a sample tube, and vertical sections were observed by SEM. In the run products, pyrite dissolved at the lower part of the starting material. In the upper half of the sample tube, pyrite crystals precipitated on quartz surface. Crystallization density depends on temperature gradient of the fluid. Predominant morphology of the pyrite crystals consists (100) plains. Tiny framboidal aggregates and crystals with (210) plains also occur. In the run products of longer than 3 days run durations

  4. Dieta de murciélagos nectarívoros del Parque Nacional Cerros de Amotape, Tumbes

    Directory of Open Access Journals (Sweden)

    Edith Arias

    2011-07-01

    Full Text Available En el Perú se reporta la presencia de 18 especies de murciélagos nectarívoros, sin embargo se cuenta con poca información sobre la dieta de estas especies. En este estudio se reporta por primera vez la dieta de los nectarívoros Glossophaga soricina, Lonchophylla hesperia y Anoura geoffroyi en el bosque seco ecuatorial y del bosque tropical del Pacífico del Parque Nacional Cerros de Amotape, Tumbes. Analizamos 21 contenidos gastrointestinales e identificamos ocho morfotipos de polen pertenecientes a las familias Bombacaceae, Cactaceae, Fabaceae, Solanaceae, Rubiaceae, Myrtaceae, Malvaceae y Rosaceae. Encontramos evidencia del síndrome de quiropterofilia en Bombacaceae, Cactaceae, Fabaceae, Solanaceae y Rubiaceae. Observamos que A. geoffroyi consume polen de Ceiba trichistandra, Solanaceae y Rubiacea; G. soricina consume de Abutilon reflexum, Armathocereus cartwrightianus, C. trichistandra y Rubiaceae; y L. hesperia de A. cartwrightianus, Eriobotrya japonica, Fabaceae y Psidium sp.; sugiriendo una dieta generalista en estas especies. Los murciélagos G. soricina y A. geoffroyi comparten el consumo del ceibo C. trichistandra y de la Rubiaceae, mientras que G. soricina comparte con L. hesperia el consumo del cactus A. cartwrightianus. Los otros morfotipos de polen no fueron compartidos entre murciélagos. Se encuentra además que el ceibo C. trichistandra fue la especie más consumida, especialmente por G. soricina.

  5. The Cerro Bitiche Andesitic Field: petrological diversity and implications for magmatic evolution of mafic volcanic centers from the northern Puna

    Science.gov (United States)

    Maro, Guadalupe; Caffe, Pablo J.

    2016-07-01

    The Cerro Bitiche Andesitic Field (CBAF) is one of the two largest mafic volcanic fields in northern Puna (22-24° S) and is spatially and temporally associated with ignimbrites erupted from some central Andean Altiplano-Puna Volcanic Complex calderas. The CBAF comprises seven scoria cones and widespread high-K calcalkaline lava flows that cover an area of 200 km2. Although all erupted rocks have a relatively narrow chemical range (56-62 % SiO2, 3-6 % MgO), there is a broad diversity of mineral compositions and textures. The least evolved lavas (˜58-61 % SiO2) are high-Mg andesites with scarce (<10 %) microphenocrysts of either olivine or orthopyroxene. The small compositional range and low phenocryst content indicate evolution controlled by low percentages (<10 %) of fractional crystallization of olivine and clinopyroxene of magmas similar to the least evolved rocks from the field, accompanied by assimilation during rapid ascent through the crust. Evolved andesites (˜62 wt% SiO2), on the other hand, are porphyritic rocks with plagioclase + orthopyroxene + biotite and ubiquitous phenocryst disequilibrium textures. These magmas were likely stored in crustal reservoirs, where they experienced convection caused by mafic magma underplating, magma mixing, and/or assimilation. Trace element and mineral compositions of CBAF lavas provide evidence for complex evolution of distinct magma batches.

  6. Palynological analysis of camelid coprolites: seasonality in the use of the site Cerro Casa de Piedra 7 (Santa Cruz, Argentina)

    Science.gov (United States)

    Velázquez, Nadia Jimena; Burry, Lidia Susana; Fugassa, Martín Horacio; Civalero, María Teresa; Aschero, Carlos Alberto

    2014-01-01

    Palynological, palaeoparasitological and paleobotanical studies of coprolites found in archaeological sites from Perito Moreno National Park (47°57‧S72°05‧W) yielded information on diet, palaeoenvironment and health. These studies allowed adding evidence to the reconstruction of life history of the hunter-gatherers that inhabited Patagonia during the Holocene. We examined the season of the year when camelid Lama guanicoe coprolites (5400 ± 64 yr 14C BP to 9640 ± 190 yr 14C BP) were deposited at Cerro Casa de Piedra 7 (site CCP7). The study used palynological evidence and comparison with pollen spectra of modern feces collected during summer, fall, winter and spring of 2010. The dominant types were: pollen of Nothofagus, Empetrum rubrum, Asteraceae subfam. Asteroideae, Nassauvia, Caryophyllaceae and Poaceae; fern spores; remains of Eimeria macusaniensis; and plant remains of Poaceae, Festuca pallescens, Stipa speciosa, Armeria maritima, Gaultheria mucronata and E. rubrum. Pollen spectra of modern and fossil feces were used for multivariate analysis. Coprolites associated to fall and winter modern feces. These results and those obtained from pollen concentration values and the presence of pollen types indicators of seasonality, allowed the determination of summer, fall and winter coprolites. However, caution must be taken with the seasonality results of coprolites dated earlier than 9000 years BP since the environmental conditions differed from now. The site was probably a camelid shelter during the unfavorable seasons.

  7. Analysis of heavy oils: Method development and application to Cerro Negro heavy petroleum detailed separation and analysis of acidic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.B.; Yu, S.K.T.; Green, J.A.; Doughty, D.A.; Vogh, J.W.; Grigsby, R.D.

    1989-10-01

    An HPLC method for fractionation of whole acid concentrates into nominal compound class subfractions is described. The method utilizes silica columns and gradient elution with eluents containing a strong base, tetramethyl-ammonium hydroxide. The performance of the method is evaluated through analysis of subfractions obtained from a coal liquid, Wilmington, CA, petroleum and Cerro Negro heavy oil. Methods developed specifically for analysis of whole acid concentrates and subfractions are described in detail. These include: (1) an infrared method for determination of total hydroxyl and carboxyl groups after their conversion to trifluoroacetate and 2,2,2-trifluoresters, respectively. (2) an NMR method for functional group analysis based on methylation of acidic groups with {sup 13}C-enriched methyl iodide, (3) a nonaqueous titration procedure employing the potassium salt of dimethyl sulfoxide as a titrant for acidic compounds, (4) GC/MS analysis of hydroxyaromatic compounds after their conversion to trifluoroacetate esters, and (5) probe microdistillation high resolution mass spectrometric analysis of acid fractions exhibiting low volatility. 146 refs., 38 figs., 27 tabs.

  8. Late Quaternary vegetation, fire and climate history reconstructed from two cores at Cerro Toledo, Podocarpus National Park, southeastern Ecuadorian Andes

    Science.gov (United States)

    Brunschön, Corinna; Behling, Hermann

    2009-11-01

    The last ca. 20,000 yr of palaeoenvironmental conditions in Podocarpus National Park in the southeastern Ecuadorian Andes have been reconstructed from two pollen records from Cerro Toledo (04°22'28.6"S, 79°06'41.5"W) at 3150 m and 3110 m elevation. Páramo vegetation with high proportions of Plantago rigida characterised the last glacial maximum (LGM), reflecting cold and wet conditions. The upper forest line was at markedly lower elevations than present. After ca. 16,200 cal yr BP, páramo vegetation decreased slightly while mountain rainforest developed, suggesting rising temperatures. The trend of increasing temperatures and mountain rainforest expansion continued until ca. 8500 cal yr BP, while highest temperatures probably occurred from 9300 to 8500 cal yr BP. From ca. 8500 cal yr BP, páramo vegetation re-expanded with dominance of Poaceae, suggesting a change to cooler conditions. During the late Holocene after ca. 1800 cal yr BP, a decrease in páramo indicates a change to warmer conditions. Anthropogenic impact near the study site is indicated for times after 2300 cal yr BP. The regional environmental history indicates that through time the eastern Andean Cordillera in South Ecuador was influenced by eastern Amazonian climates rather than western Pacific climates.

  9. Material control and accountability (MC and A) recovery from the Cerro Grande fire at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    During the week of May 10-14, 2000, the Cerro Grande Fire scorched over 40,000 acres of prime forestland and destroyed over 400 homes in the Los Alamos community and several structures at the Los Alamos National Laboratory (LANL). Of the land affected by the fire, nearly one quarter of it was Laboratory property. All of LANL's 64 material balance areas (MBAs) were affected to some degree, but one Category I technical area and several Category I11 and IV areas sustained heavy damage. When the MC and A personnel were allowed to return to work on May 23, they addressed the following problems: How do we assure both ourselves and the Department of Energy (DOE) that no nuclear materials had been compromised? How do we assist the nuclear material (NM) custodians and their operating groups so that they can resume normal MC and A operations? Immediately after the return to work, the Laboratory issued emergency MC and A assurance actions for Category I through Category IV facilities. We conducted special inventories, area walkthroughs, and other forms of evaluation so that within a month after the fire, we were able to release the last MBA to resume work and assure that all nuclear material had been accounted for. This paper discusses the measures LANL adopted to ensure that none of its nuclear material had been compromised.

  10. Evolving patterns of the fluids within the TAG hydrothermal field

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The mixing of seawater/hydrothermal fluid within the large seafloor hydrothermal sulfide deposits plays a key role in the formation processes of the sulfide deposits.Some issues attract considerable attentions in the study of seafloor hydrothermal system in recent years,such as the relationships among different types of vent fluids,the characteristics of chemical compositions and mineral assemblages of the hydrothermal deposits and their governing factors.Combined with the measured data of hydrothermal fluid in the TAG field,the thermodynamic model of mixing processes of the heated seawater at different temperatures and the hydrothermal fluid is calculated to understand the precipitation mechanism of anhydrite and the genetic relationships between the black and white smoker fluids within the TAG mound.The results indicate that the heating of seawater and the mixing of hydrothermal fluid/seawater are largely responsible for anhydrite precipitation and the temperature of the heated seawater is not higher than 150 ℃ and the temperature of the end-member hydrothermal fluid is not lower than 400℃.Based on the simulated results,the evolving patterns of fluids within the TAG deposit are discussed.The mixed fluid of the end-member hydrothermal fluid and the seawater heated by wall rock undergoes conductive cooling during upflowing within the deposit and forms "White Smoker" eventually.In addition,the end-member hydrothermal fluid without mixed with seawater,but undergoing conductive cooling,vents out of the deposit and forms "Black Smoker".

  11. Hydrothermal synthesis of sodium titanate nanotubes

    International Nuclear Information System (INIS)

    From suspension of nanoparticles TiO2 in concentrated water solution of NaOH were prepared by hydrothermal synthesis sodium titanates particles with different shapes. Influence of synthesis duration under temperature 180 grad C on the change of particles shapes was observed. The result of experiment showed that one day synthesis resulted to obtained product with high content of nanotubes, but the extension of this period led to the transformation of product's shape into stripes. From the results of experiment follows that as a precursor for TiO2 nanotubes preparation may be used only products of hydrothermal synthesis, which duration of pressure synthesis was not longer than 24 hours. (authors)

  12. Whole Algae Hydrothermal Liquefaction Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, Mary J.; Davis, Ryan; Jones, Susanne B.; Zhu, Yunhua

    2013-03-31

    In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to hydrocarbon fuels to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This pathway case investigates the feasibility of using whole wet microalgae as a feedstock for conversion via hydrothermal liquefaction. Technical barriers and key research needs have been assessed in order for the hydrothermal liquefaction of microalgae to be competitive with petroleum-derived gasoline, diesel and jet range blendstocks.

  13. PZT Powders Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    ZHU Kong-Jun, ZHU Ren-Qiang, DONG Na-Na, GU Hong-Hui, QIU Jin-Hao, JI Hong-Li

    2012-05-01

    Full Text Available Lead zirconate titanate (PZT) powders with single―phase, cubic morphology and average size of 1 μm were synthesized using hydrothermal methods. Effects of KOH concentration, hydrothermal treatment time and Pb excess were investigated. The results show that KOH concentration has an important influence on the solid solubility of Pb ion in A―site of PZT perovskite structure. The concentration of Pb2+ vacancies increased with the increase of OH― concentration. However, this kind of deficiency could be compensated by adding more Pb ions in the raw materials, and more Pb ions were needed to add with higher alkaline concentration in the starting solution. But excessive compensation of Pb ions would result in the appearance of the second phase.

  14. U and Th Concentration and Isotopic Composition of Hydrothermal Fluids at the Lost City Hydrothermal Field

    Science.gov (United States)

    Ludwig, K. A.; Shen, C.; Cheng, H.; Edwards, R.; Kelley, D. S.; Butterfield, D. A.

    2006-12-01

    Uranium and Th concentration and isotopic composition of hydrothermal fluids at the Lost City Hydrothermal Field (LCHF) were determined using multi-collector inductively coupled plasma mass spectrometry (MC-ICP- MS). The LCHF is an off-axis, serpentinite-hosted hydrothermal system located at 30°N near the Mid- Atlantic Ridge. Carbonate chimneys reaching 60 m in height vent alkaline (pH~10), calcium-rich fluids at 40- 91°C and the towers are home to dense microbial communities. Vent fluid and seawater U and Th concentration and isotopic composition data provide critical information for constraining U-Th chimney ages. The increased sensitivity (1-2%) of MC-ICP-MS combined with an Aridus nebulization system allows the precise measurement of small quantities of sample (~150 ml) with low concentrations (Thorium concentrations of fluids are close to deep seawater values. U and Th isotopic compositions are reported at the permil level. These data may provide new insights into the role of serpentinite-hosted hydrothermal systems in the budgets of U and Th in the ocean. Techniques presented in this study may be applied to other hydrothermal and seep environments.

  15. Stable light isotope biogeochemistry of hydrothermal systems

    Science.gov (United States)

    Des Marais, D. J.

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.

  16. The fate of lignin during hydrothermal pretreatment

    OpenAIRE

    Heather L. Trajano; Engle, Nancy L; Foston, Marcus; Ragauskas, Arthur J; Tschaplinski, Timothy J; Wyman, Charles E

    2013-01-01

    Background Effective enzymatic hydrolysis of lignocellulosic biomass benefits from lignin removal, relocation, and/or modification during hydrothermal pretreatment. Phase transition, depolymerization/repolymerization, and solubility effects may all influence these lignin changes. To better understand how lignin is altered, Populus trichocarpa x P. deltoides wood samples and cellulolytic enzyme lignin (CEL) isolated from P. trichocarpa x P. deltoides were subjected to batch and flowthrough pre...

  17. Hydrothermal optimal power flow using continuation method

    International Nuclear Information System (INIS)

    The problem of optimal economic operation of hydrothermal electric power systems is solved using powerful continuation method. While in conventional approach, fixed generation voltages are used to avoid convergence problems, in the algorithm, they are treated as variables so that better solutions can be obtained. The algorithm is tested for a typical 5-bus and 17-bus New Zealand networks. Its capabilities and promising results are assessed

  18. Estratigrafía y vertebrados (Aves y Mammalia de la Formación Cerro Bandera, Mioceno Temprano de la Provincia del Neuquén, Argentina Stratigraphy and vertebrates (Aves and Mammalia from the Cerro Bandera Formation, Early Miocene of Neuquén Province, Argentina

    Directory of Open Access Journals (Sweden)

    Alejandro Kramarz

    2005-07-01

    Full Text Available La Formación Cerro Bandera comprende una serie de pequeños afloramientos aislados, que conforman los relictos de un antiguo relleno aluvial desarrollado sobre pequeños valles locales. Se compone de una sucesión de depósitos piroclásticos reelaborados con intercalaciones de piroclastitas primarias y escasos niveles de areniscas. Estos depósitos fueron originalmente reconocidos en el extremo nordeste de la Barda Negra, sur de Cerro Bandera y noroeste de Sierra del Portezuelo; nuevos afloramientos son reconocidos aquí en la vertiente noroeste del cerro Bayo Mesa, Provincia del Neuquén, Argentina. Los restos fósiles exhumados corresponden a aves (Falconidae y mamíferos (17 familias, entre los que se destacan Cramauchenia normalis Ameghino, Proadinotherium cf. P. muensteri Ameghino, Eosteiromys sp. y Caviocricetus lucasi Vucetich y Verzi, junto con una especie de Protypotherium con dentadura más primitiva que las conocidas para la Edad Santacrucense. Esta asociación confirma una Edad Mamífero Colhuehuapense (Mioceno Temprano para esta unidad. La fauna exhibe marcadas diferencias con la registrada en la sección inferior de la Formación Chichinales, Provincia de Río Negro. El grado de diferenciación faunística entre estas dos unidades posiblemente sincrónicas podría obedecer a diferencias en los factores paleoambientales localesThe Cerro Bandera Formation comprises a series of isolated outcrops that represent the relicts of an old alluvial filling developed on small local valleys. It is composed of a succession of reworked pyroclastic deposits alternating with primary pyroclastic and scant sandstone levels. These deposits were originally recognized at the northeast of Barda Negra, south of Cerro Bandera and northwest of Sierra del Portezuelo; new exposures are herein recognised to the northwestern slope of Cerro Bayo Mesa, Neuquén Province, Argentina. The recovered fossil remains correspond to birds (Falconidae and 17 families of

  19. Hydrothermal synthesis map of bismuth titanates

    Science.gov (United States)

    Sardar, Kripasindhu; Walton, Richard I.

    2012-05-01

    The hydrothermal synthesis of four bismuth titanate materials from common bismuth and titanium precursors under hydrothermal conditions is described. Reaction of NaBiO3·2H2O and anatase TiO2 in concentrated NaOH solution at 240 °C is shown to produce perovskite and sillenite phases Na0.5Bi0.5TiO3 and Bi12TiO20, depending on the ratio of metal precursors used. When KOH solution is used and a 1:1 ratio of the same precursors, a pyrochlore Bi1.43Ti2O6(OH)0.29(H2O)0.66 is formed. The use of a mixture of HNO3 and NaOH is shown to facilitate the formation of the Aurivillius-type bismuth titanate Bi4Ti3O12. The phases have been isolated separately as phase-pure powders and profile refinement of powder X-ray diffraction data allows comparisons with comparable materials reported in the literature. Analysis of Bi LIII-edge X-ray absorption near edge structure (XANES) spectra of the materials shows the oxidation state of bismuth is +3 in all of the hydrothermally derived products.

  20. Surface roughened zirconia: towards hydrothermal stability.

    Science.gov (United States)

    Camposilvan, Erik; Flamant, Quentin; Anglada, Marc

    2015-07-01

    Surface roughness is needed in several yttria-stabilized zirconia components used in restorative dentistry for osseointegration or adhesion purposes. This can be achieved by different treatments, which may also modify the microstructure of the surface. Among them, sandblasting and chemical etching are widely used, but their effect on hydrothermal aging of zirconia is not fully understood. In the present work, the zirconia long-term stability of rough surfaces prepared by these techniques is analyzed and a method is proposed for preventing hydrothermal aging while maintaining the original surface appearance and mechanical properties. The method involves pressure infiltration of a Cerium salt solution on the roughened surfaces followed by a thermal treatment. The solution, trapped by surface defects and small pores, is decomposed during thermal treatment into Cerium oxide, which is diffused at high temperature, obtaining Ce co-doping in the near-surface region. In addition, the microstructural changes induced in the near-surface by sandblasting or chemical etching are removed by the thermal treatment together with surface defects. No color modification was observed and the final roughness parameters were in the range of existing implants of proved good osseointegration. The aging resistance of Ce co-doped materials was strongly enhanced, showing the absence of aging after artificial degradation, increasing in this way the surface mechanical integrity. The proposed treatment is easily applicable to the current manufacturing procedures of zirconia dental posts, abutments, crowns and dentures, representing a solution to hydrothermal aging in these and other biomedical applications. PMID:25867636

  1. ESTRATEGIA DE REMONTAJE APLICADA SOBRE EL REGISTRO CERÁMICO DEL SITIO LOS TRES CERROS 1 (DELTA SUPERIOR DEL RÍO PARANÁ / Refitting applied to pottery from Los Tres Cerros 1 site (Upper Delta of Paraná River

    Directory of Open Access Journals (Sweden)

    Violeta Soledad Di Prado

    2014-12-01

    Full Text Available El sitio arqueológico Los Tres Cerros 1 se encuentra ubicado en el departamento Victoria, Entre Ríos, y consiste en una estructura monticular con una compleja historia ocupacional. La abundancia y fragmentación del registro cerámico del sitio, llevaron a aplicar la estrategia de remontajes, con el propósito de reconstruir la historia de vida de las vasijas e identificar las prácticas humanas y los agentes naturales que actuaron en la configuración del depósito. Sobre una muestra del total de tiestos recuperados en la cuadrícula 1, se realizaron 43 remontajes, que unen fragmentos del mismo nivel y de diferentes niveles. Se identificaron semejanzas en las elecciones técnicas similares (i.e., agregado de tiesto molido, aplicación de pigmento y de surco rítmico efectuadas en distintas etapas del proceso de elaboración del número mínimo de vasijas estimado (NMV= 49. Se reconocieron contenedores utilizados sobre el fuego, posiblemente para la cocción, y piezas probablemente empleadas para servir. Por último, se propusieron hipótesis en torno a la integridad del registro y, al menos para el sector superior de la secuencia estratigráfica, se infirió un evento de ocupación que no fue mayormente disturbado en momentos posteriores al descarte.   Palabras clave: alfarería, remontajes, elecciones tecnológicas, prácticas de uso, procesos de formación de sitio.   Abstract Los Tres Cerros 1 archaeological site is located in Victoria department, Entre Ríos province, and it is a mound with a complex occupational history. The abundance and fragmentation of the ceramic record recovered from this site, led to apply the refitting strategy in order to reconstruct the vessels’ life history and identify human practices and natural agents that took part in the site configuration. From a ceramic sample of the whole recovered in grid 1, 43 reassemblies were made, joining sherds from the same level, as well as from different levels. Similar

  2. Hydrothermal synthesis map of bismuth titanates

    Energy Technology Data Exchange (ETDEWEB)

    Sardar, Kripasindhu [Department of Chemistry, University of Warwick, Coventry, CV4 7AL (United Kingdom); Walton, Richard I., E-mail: r.i.walton@warwick.ac.uk [Department of Chemistry, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2012-05-15

    The hydrothermal synthesis of four bismuth titanate materials from common bismuth and titanium precursors under hydrothermal conditions is described. Reaction of NaBiO{sub 3}{center_dot}2H{sub 2}O and anatase TiO{sub 2} in concentrated NaOH solution at 240 Degree-Sign C is shown to produce perovskite and sillenite phases Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} and Bi{sub 12}TiO{sub 20}, depending on the ratio of metal precursors used. When KOH solution is used and a 1:1 ratio of the same precursors, a pyrochlore Bi{sub 1.43}Ti{sub 2}O{sub 6}(OH){sub 0.29}(H{sub 2}O){sub 0.66} is formed. The use of a mixture of HNO{sub 3} and NaOH is shown to facilitate the formation of the Aurivillius-type bismuth titanate Bi{sub 4}Ti{sub 3}O{sub 12}. The phases have been isolated separately as phase-pure powders and profile refinement of powder X-ray diffraction data allows comparisons with comparable materials reported in the literature. Analysis of Bi L{sub III}-edge X-ray absorption near edge structure (XANES) spectra of the materials shows the oxidation state of bismuth is +3 in all of the hydrothermally derived products. - Graphical abstract: Use of NaBiO{sub 3}{center_dot}2H{sub 2}O and TiO{sub 2} as reagents under hydrothermal conditions allows the phase-pure preparation of four crystalline bismuth titanate materials. Highlights: Black-Right-Pointing-Pointer NaBiO{sub 3} and TiO{sub 2} under hydrothermal conditions allow formation of bismuth titanates. Black-Right-Pointing-Pointer Synthesis of four distint phases has been mapped. Black-Right-Pointing-Pointer Bi LIII-edge XANES shows Bi is reduced to oxidation state +3 in all materials. Black-Right-Pointing-Pointer A new hydrated bismuth titanate pyrochlore has been isolated.

  3. Proposed geologic model based on geophysical well logs

    Energy Technology Data Exchange (ETDEWEB)

    Diaz C, S.; Puente C, I.; de la Pena L, A.

    1981-01-01

    An investigation of the subsurface based on a qualitative interpretation of well logs was carried out at Cerro Prieto to obtain information on the distribution of the different lithofacies that make up a deltaic depositional system. The sedimentological interpretation derived from the resistivity and spontaneous potential are shown in several cross-sections of the field. In addition to the sedimentological interpretation, a map of the structural geology of the region based on well logs and available geophysical information was prepared, including the results of gravity and seismic refraction surveys. The depth to the zone of hydrothermal alteration described by Elders (1980) was found by means of temperature, electrical, and radioactive logs. Two maps showing the configuration of the top of this anomaly show a clear correlation with the gravity anomalies found in the area.

  4. Coupled Process Models as a Tool for Analysing Hydrothermal Systems

    OpenAIRE

    Gessner, K; Michael Kühn; V. Rath; C. Kosack; C. Clauser;  

    2009-01-01

    Hydrothermal systems are characterised by complex interactions between heat transfer, fluid flow, deformation, species transport and chemical reactions. Numerical models can provide quantitatively constrained information in regions where acquisition of new data is difficult or expensive thus providing a means for reducing risks, costs, and effort during targeting, production, and management of resources linked to hydrothermal systems. Here we show how numerical simulations of hydrothermal pro...

  5. Hydrothermal Conditions and the Origin of Cellular Life.

    Science.gov (United States)

    Deamer, David W; Georgiou, Christos D

    2015-12-01

    The conditions and properties of hydrothermal vents and hydrothermal fields are compared in terms of their ability to support processes related to the origin of life. The two sites can be considered as alternative hypotheses, and from this comparison we propose a series of experimental tests to distinguish between them, focusing on those that involve concentration of solutes, self-assembly of membranous compartments, and synthesis of polymers. Key Word: Hydrothermal systems. PMID:26684507

  6. Interactions Between Serpentinization, Hydrothermal Activity and Microbial Community at the Lost City Hydrothermal Field

    Science.gov (United States)

    Delacour, A.; Frueh-Green, G. L.; Bernasconi, S. M.; Schaeffer, P.; Frank, M.; Gutjahr, M.; Kelley, D. S.

    2008-12-01

    Seafloor investigations of slow- and ultraslow-spreading ridges have reported many occurrences of exposed mantle peridotites and gabbroic rocks on the ocean floor. Along the Mid-Atlantic Ridge, these uplifted portions of oceanic crust host high-temperature black smoker-type hydrothermal systems (e.g., Rainbow, Logatchev, Saldanha), and the more distinct low-temperature Lost City Hydrothermal Field (LCHF). Built on a southern terrace of the Atlantis Massif, the LCHF is composed of carbonate-brucite chimneys that vent alkaline and low-temperature (40-90°C) hydrothermal fluids. These fluids are related to serpentinization of mantle peridotites, which together with minor gabbroic intrusions form the basement of the LCHF. Long-lived hydrothermal activity at Lost City led to extensive seawater-rock interaction in the basement rocks, as indicated by seawater-like Sr- and mantle to unradiogenic Nd-isotope compositions of the serpentinites. These high fluid fluxes in the southern part of the massif influenced the conditions of serpentinization and have obliterated the early chemical signatures in the serpentinites, especially those of carbon and sulfur. Compared to reducing conditions commonly formed during the first stages of serpentinization, serpentinization at Lost City is characterized by relatively oxidizing conditions resulting in a predominance of magnetite, the mobilization/dissolution and oxidation of igneous sulfides to secondary pyrite, and the incorporation of seawater sulfate, all leading to high bulk-rock S-isotope compositions. The Lost City hydrothermal fluids contain high concentrations in methane, hydrogen, and low-molecular weight hydrocarbons considered as being produced abiotically. In contrast, organic compounds in the serpentinites are dominated by the occurrences of isoprenoids (pristane, phytane, and squalane), polycyclic compounds (hopanes and steranes), and higher abundances of C16 to C20 n-alkanes indicative of a marine organic input. We

  7. Theoretical constraints of physical and chemical properties of hydrothermal fluids on variations in chemolithotrophic microbial communities in seafloor hydrothermal systems

    Science.gov (United States)

    Nakamura, Kentaro; Takai, Ken

    2014-12-01

    In the past few decades, chemosynthetic ecosystems at deep-sea hydrothermal vents have received attention as plausible analogues to the early ecosystems of Earth, as well as to extraterrestrial ecosystems. These ecosystems are sustained by chemical energy obtained from inorganic redox substances (e.g., H2S, CO2, H2, CH4, and O2) in hydrothermal fluids and ambient seawater. The chemical and isotope compositions of the hydrothermal fluid are, in turn, controlled by subseafloor physical and chemical processes, including fluid-rock interactions, phase separation and partitioning of fluids, and precipitation of minerals. We hypothesized that specific physicochemical principles describe the linkages among the living ecosystems, hydrothermal fluids, and geological background in deep-sea hydrothermal systems. We estimated the metabolic energy potentially available for productivity by chemolithotrophic microorganisms at various hydrothermal vent fields. We used a geochemical model based on hydrothermal fluid chemistry data compiled from 89 globally distributed hydrothermal vent sites. The model estimates were compared to the observed variability in extant microbial communities in seafloor hydrothermal environments. Our calculations clearly show that representative chemolithotrophic metabolisms (e.g., thiotrophic, hydrogenotrophic, and methanotrophic) respond differently to geological and geochemical variations in the hydrothermal systems. Nearly all of the deep-sea hydrothermal systems provide abundant energy for organisms with aerobic thiotrophic metabolisms; observed variations in the H2S concentrations among the hydrothermal fluids had little effect on the energetics of thiotrophic metabolism. Thus, these organisms form the base of the chemosynthetic microbial community in global deep-sea hydrothermal environments. In contrast, variations in H2 concentrations in hydrothermal fluids significantly impact organisms with aerobic and anaerobic hydrogenotrophic metabolisms

  8. Cuprous oxide thin films grown by hydrothermal electrochemical deposition technique

    International Nuclear Information System (INIS)

    Semiconducting cuprous oxide films were grown by a hydrothermal electro-deposition technique on metal (Cu) and glass (ITO) substrates between 60 °C and 100 °C. X-ray diffraction studies reveal the formation of cubic cuprous oxide films in different preferred orientations depending upon the deposition technique used. Film growth, uniformity, grain size, optical band gap and photoelectrochemical response were found to improve in the hydrothermal electrochemical deposition technique. - Highlights: • Cu2O thin films were grown on Cu and glass substrates. • Conventional and hydrothermal electrochemical deposition techniques were used. • Hydrothermal electrochemical growth showed improved morphology, thickness and optical band gap

  9. Heat and mass flux estimation of modern seafloor hydrothermal activity

    Institute of Scientific and Technical Information of China (English)

    ZHAI Shikui; WANG Xingtao; YU Zenghui

    2006-01-01

    Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of seawater properties. Currently, estimating heat flux is based on the observation data of hydrothermal smokers, low-temperature diffusive flow and mid-ocean ridge mainly. But there are some faults, for example, there is lack of a concurrent conductive item in estimating the heat flux by smokers and the error between the half-space cooling model and the observation data is too large. So, three kinds of methods are applied to re-estimating the heat flux of hydrothermal activity resepectively, corresponding estimation is 97.359 GW by hydrothermal smoker and diffusive flow, 84.895 GW by hydrothermal plume, and 4.11 TW by exponential attenuation method put forward by this paper. Research on mass flux estimation is relatively rare, the main reason for this is insufficient field observation data. Mass fluxes of different elements are calculated using hydrothermal vent fluid data from the TAG hydrothermal area on the Mid-Atlantic Ridge for the first time. Difference of estimations by different methods reflects the researching extent of hydrothermal activity, and systematically in-situ observation will help to estimate the contribution of hydrothermal activity to ocean chemical environment, ocean circulation and global climate precisely.

  10. Geología de la región del Cerro Guanaquero, Río Diamante, Mendoza

    Directory of Open Access Journals (Sweden)

    Federico Fuentes

    2008-03-01

    Full Text Available El estudio realizado presenta nuevos datos sobre un sector poco conocido de la Cordillera Principal de Mendoza, en la alta cuenca del río Diamante en las adyacencias del cerro Guanaquero, y los primeros datos geocronológicos de sus rocas volcánicas. Las unidades geológicas presentes en el área se dividen en cuatro grupos principales: secuencias sedimentarias mesozoicas marinas y continentales intensamente plegadas y falladas; intrusivos y volcanitas intermedias de edad neógena; rocas volcánicas pliocenas a recientes de composición intermedia a básica, y depósitos cuaternarios inconsolidados. El cerro Guanaquero, un estratovolcán pliocuaternario intensamente erosionado por glaciares pleistocenos, con sus 4.841 metros es el rasgo orográfico más prominente. Está constituido esencialmente por andesitas grises porfíricas, piroxénicas a biotíticas. Intercaladas con las coladas andesíticas se presentan depósitos piroclásticos, aglomerados volcánicos, ignimbritas y basaltos. La datación de una andesita por el método K-Ar en roca total arrojó una edad de 1,4 ± 0,1 Ma. La deformación ándica comenzó en forma de una faja plegada y corrida de piel fina, con pliegues por despegue en el sector occidental y por propagación de falla en el oriental. La compresión al oeste de los 69º47´O terminó por invertir la fallas normales del rift mesozoico. A lo largo de este meridiano se encuentra la falla más importante de la región, la que se ha correlacionado con la falla Malargüe, bien desarrollada en latitudes más australes. Esta falla limita la faja plegada y corrida del Aconcagua, de naturaleza epidérmica, y la faja plegada y corrida de Malargüe, controlada por la inversión tectónica del basamento. El volcanismo fue muy intenso en el Plioceno y el Cuaternario, correspondiendo a un período de empinamiento de la placa oceánica subducida, en el que la región ha sido levantada pasivamente. La alta resistencia a la erosión de

  11. Sedimentología y evolución paleoambiental de la Formación Patquía (Pérmico en el extremo sur de la sierra de Maz y cerro Bola, provincia de La Rioja, Argentina Sedimentology and palaeoenvironmental evolution of the Patquía Formation (Permian, in the Sierra de Maz and cerro Bola, La Rioja Province, Argentina

    Directory of Open Access Journals (Sweden)

    A. T. Caselli

    2002-12-01

    Full Text Available En este trabajo se analizan las características sedimentológicas de la Formación Patquía en la Sierra de Maz y en el Cerro Bola (perfiles de cerro Guandacol, La Cortadera, cerro Noqués y cerro Bola, donde fueron reconocidas siete asociaciones de facies. La facies A está compuesta por aglomerados, brechas y conglomerados depositados en pequeños abanicos aluviales. Areniscas gruesas y conglomerados integran la facies B, la que fue probablemente depositada en planicies fluviales entrelazadas. La facies C incluye conglomerados y areniscas gruesas correspondientes a sistemas fluviales de baja sinuosidad. La facies D es la más extendida regionalmente y está compuesta por sabulitas, areniscas, pelitas y tobas, interpretadas como cursos fluviales de elevada sinuosidad. Un episodio de sedimentación eólica está registrado en la facies E, constituida por areniscas finas a medianas mostrando estratificación entrecruzada de gran escala. La facies F, areniscas y pelitas interestratificadas, fue depositada en lagos clásticos, someros y permanentes. La facies G incluye areniscas blanquecinas y pelitas rosadas, con intercalaciones de areniscas finas con estratificación entrecruzada de gran escala, sedimentadas en sistemas fluviales sinuosos con migración de dunas eólicas en las planicies. La composición modal de las areniscas permite identificar tres petrofacies. La cuarzoféldica representa el aporte del basamento de las Sierras Pampeanas. La cuarzofeldlítica incluye fragmentos de volcanitas ácidas y mesosilícicas relacionadas a la faja volcánica Permo-Triásica ubicada al oeste. La litomíxtica está dominada por líticos sedimentarios y paleovolcánicos provenientes de la Precordillera. Finalmente, el análisis estratigráfico de las facies arriba descriptas permitió la identificación de dos secuencias depositacionales.The sedimentological characteristics of the Patquía Formation in the Sierra de Maz and Cerro Bola areas were analyzed

  12. Dynamic characterization of the M19 area, Cerro Negro Field, corresponding to Carabobo Block, Orinoco oil belt.

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, A. [PDVSA Petroleos de Venezuela SA, Caracas (Venezuela, Bolivarian Republic of). E and P Orinoco Belt Division

    2009-07-01

    The Orinoco oil belt in Venezuela is divided into the Boyaca, Junin, Ayacucho and Carabobo areas. This study characterized the M19 area of the Cerro Negro Field, corresponding to Carabobo Block, one of the most prospective areas in the Orinoco oil belt. This small section of Carabobo Block involves a stock tank original oil in place of 11,000 MMSTB with an API gravity between 7.8 and 8. The initial reservoir pressure is about 1,200 psia and solution gas drive is the predominant primary production mechanism. The range of viscosities varies from 2,000 to 6,000 cps. The average porosity is 30 per cent and permeability varies from 2 to 7 Darcies. This study focused on obtaining a better understanding of the reservoir behaviour. Results from geophysics, petrophysics, sedimentology, and reservoir engineering analysis were integrated in order to characterize the area with a simulation model and to address many uncertainties which have affected exploitation of the oil field since 1980. These issues are related to vertical drainage, horizontal well spacing, and horizontal well length. The pressure model did not reveal any evidence of main compartments within the reservoir. The petrophysical properties and fluid model honours the production behaviour of the whole field. The critical gas saturation that is needed to achieve a production gas match is approximately 3 per cent. The optimum horizontal length should not exceed 4600 feet and vertical drainage suggests a well spacing of 80 ft in order to minimize interference. The cold recovery factor would increase by reducing the horizontal spacing up to 200 mts. The need for implementing a thermal and chemical process to increase the recovery factor was reinforced. 7 refs., 5 tabs., 47 figs.

  13. Columnar jointing in vapor-phase-altered, non-welded Cerro Galán Ignimbrite, Paycuqui, Argentina

    Science.gov (United States)

    Wright, Heather M.; Lesti, Chiara; Cas, Ray A.F.; Porreca, Massimiliano; Viramonte, Jose G.; Folkes, Christopher B.; Giordano, Guido

    2011-01-01

    Columnar jointing is thought to occur primarily in lavas and welded pyroclastic flow deposits. However, the non-welded Cerro Galán Ignimbrite at Paycuqui, Argentina, contains well-developed columnar joints that are instead due to high-temperature vapor-phase alteration of the deposit, where devitrification and vapor-phase crystallization have increased the density and cohesion of the upper half of the section. Thermal remanent magnetization analyses of entrained lithic clasts indicate high emplacement temperatures, above 630°C, but the lack of welding textures indicates temperatures below the glass transition temperature. In order to remain below the glass transition at 630°C, the minimum cooling rate prior to deposition was 3.0 × 10−3–8.5 × 10−2°C/min (depending on the experimental data used for comparison). Alternatively, if the deposit was emplaced above the glass transition temperature, conductive cooling alone was insufficient to prevent welding. Crack patterns (average, 4.5 sides to each polygon) and column diameters (average, 75 cm) are consistent with relatively rapid cooling, where advective heat loss due to vapor fluxing increases cooling over simple conductive heat transfer. The presence of regularly spaced, complex radiating joint patterns is consistent with fumarolic gas rise, where volatiles originated in the valley-confined drainage system below. Joint spacing is a proxy for cooling rates and is controlled by depositional thickness/valley width. We suggest that the formation of joints in high-temperature, non-welded deposits is aided by the presence of underlying external water, where vapor transfer causes crystallization in pore spaces, densifies the deposit, and helps prevent welding.

  14. Columnar jointing in vapor-phase-altered, non-welded Cerro Galán Ignimbrite, Paycuqui, Argentina

    Science.gov (United States)

    Wright, Heather M. N.; Lesti, Chiara; Cas, Raymond A. F.; Porreca, Massimiliano; Viramonte, José G.; Folkes, Chris B.; Giordano, Guido

    2011-12-01

    Columnar jointing is thought to occur primarily in lavas and welded pyroclastic flow deposits. However, the non-welded Cerro Galán Ignimbrite at Paycuqui, Argentina, contains well-developed columnar joints that are instead due to high-temperature vapor-phase alteration of the deposit, where devitrification and vapor-phase crystallization have increased the density and cohesion of the upper half of the section. Thermal remanent magnetization analyses of entrained lithic clasts indicate high emplacement temperatures, above 630°C, but the lack of welding textures indicates temperatures below the glass transition temperature. In order to remain below the glass transition at 630°C, the minimum cooling rate prior to deposition was 3.0 × 10-3-8.5 × 10-2°C/min (depending on the experimental data used for comparison). Alternatively, if the deposit was emplaced above the glass transition temperature, conductive cooling alone was insufficient to prevent welding. Crack patterns (average, 4.5 sides to each polygon) and column diameters (average, 75 cm) are consistent with relatively rapid cooling, where advective heat loss due to vapor fluxing increases cooling over simple conductive heat transfer. The presence of regularly spaced, complex radiating joint patterns is consistent with fumarolic gas rise, where volatiles originated in the valley-confined drainage system below. Joint spacing is a proxy for cooling rates and is controlled by depositional thickness/valley width. We suggest that the formation of joints in high-temperature, non-welded deposits is aided by the presence of underlying external water, where vapor transfer causes crystallization in pore spaces, densifies the deposit, and helps prevent welding.

  15. Perfil infectológico de poblaciones mapuche de Cerro Policía y Aguada Guzmán de la provincia de Río Negro

    OpenAIRE

    Rey, Jorge Alberto; Dejean, Cristina Beatriz; Niborski, Ricardo; Arrayago, Alicia M.; Kohan, Abraham I.; Carnese, Francisco R.

    1996-01-01

    Nuestro trabajo analiza la prevalencia de marcadores de algunas infecciones que afectan las poblaciones mapuche de Cerro Policía (CP) y Aguada Guzmán (AG) en la Prov. de Río Negro. Los estudios incluídos son: determinación de anticuerpos anti-Treponema pallidum, anti-Trypanosoma cruzii, anti-Echinococcus granulosus, antígeno de superficie de la Hepatitis B (HBsAg), anticuerpos contra el core de la Hepatitis B (anti-HBc), anticuerpos contra el virus de la Hepatitis A (anti-HAV). Se estudiaron ...

  16. NUEVOS APORTES AL CONOCIMIENTO DE LA HERPETOFAUNA DE LA FORMACIÓN CERRO AZUL (MIOCENO SUPERIOR), PROVINCIA DE LA PAMPA, ARGENTINA

    OpenAIRE

    AGUSTÍN SCANFERLA; Agnolín, Federico L.

    2015-01-01

    RESUMENSe describen nuevos materiales fósiles de anfibios y reptiles hallados en sedimentos referidos a la Formación Cerro Azul (Mioceno Superior), procedentes de numerosas localidades de la provincia de La Pampa, Argentina. Los nuevos registros se basan en un resto craneano de anuro asignado al géneroCeratophrys, restos de caparazón de tortugas terrestres del géneroChelonoidis, vértebras asignables al lagarto de la familia TeiidaeTupinambis, y una vértebra troncal de serpiente comparable a...

  17. TECNOLOGÍA Y SUBSISTENCIA EN EL SITIO ARQUEOLÓGICO CERRO TAPERA VÁZQUEZ (PARQUE NACIONAL PRE-DELTA, REPÚBLICA ARGENTINA)

    OpenAIRE

    Mariano Bonomo; Juan Carlos Castro; Carolina Belén Silva

    2014-01-01

    In this paper the results of the studies carried out on ceramic and bone materials recorded at Cerro Tapera Vázquez site (Argentinean Northeast) are presented. Taxonomic, anatomic and taphonomic studies of bone assemblages and technological-decorative analysis and refitting of pottery were undertaken. The site is located on a mound next to El Ceibo Creek, where 16 m2 were excavated in 2008. Abundant smooth, incised and modeled pottery (handles and zoomorphic appendages) and numerous bones rem...

  18. Apresentacão do Projeto de extensão universitaria "Fortalecimento das Capacidades das Educadoras do Programa CAIF no estado de Cerro Largo-Uruguai"

    OpenAIRE

    Mariana Porta Galván

    2015-01-01

    Dentro de la línea de investigación Estado, políticas sociales y ciudadanía en frontera, es relevante conocer la realidad de las políticas sociales orientadas a la primera infancia y sus implementaciones. Esta ponencia presenta un proyecto de extensión universitaria realizada con los centros CAIF de Cerro Largo con el propósito de fortalecer las prácticas de los operadores sociales de estos centros, a partir de las siguientes preguntas: ¿Qué características asume la implementación de esta pol...

  19. Dos tumbas de Época Altoimperial documentadas en el entorno minero de Cerro Muriano (Córdoba): I.A.U. La Mocha

    OpenAIRE

    Moreno Garrido, María Jesús; Penco Valenzuela, Fernando

    2000-01-01

    The last archaeological explorations and other researches made at Cerro Muria­no come to corroborate the importance of this mining whole wich, according to all the vestiges, was already worked during Prehistory. Lower down, we show some outstanding aspects about two burials excavated on geological rock that must be produced about the transition from I B.C. to I A.C. century. Constitute the first two examples of funeral structures wich have been verified in this space, that has been continousl...

  20. Dispersión de semillas por murciélagos frugívoros en bosques del Parque Nacional Cerros de Amotape, Tumbes, Perú

    OpenAIRE

    Sidney Novoa; Richard Cadenillas; Víctor Pacheco

    2011-01-01

    Se evaluó el rol de los murciélagos frugívoros como dispersores de semillas en tres tipos de hábitat del Parque Nacional Cerros de Amotape, Tumbes, Perú. Se analizó la dieta identificando y cuantificando las semillas encontradas en muestras fecales. Se interpreta la preferencia por los recursos vegetales, amplitud de nicho, la importancia de cada especie como dispersora y el nivel de solapamiento de nicho trófico. Se capturaron 33 especies de murciélagos, de las cuales 13 fueron predominantem...

  1. First hydrothermal active vent discovered on the Galapagos Microplate

    Science.gov (United States)

    Tao, C.; Li, H.; Wu, G.; Su, X.; Zhang, G.; Chinese DY115-21 Leg 3 Scientific Party

    2011-12-01

    The Galapagos Microplate (GM) lies on the western Gaplapagos Spreading Center (GSC), representing one of the classic Ridge-Ridge-Ridge (R-R-R) plate boundaries of the Nazca, Cocos, and Pacific plates. The presence of the 'black smoke' and hydrothermal vent community were firstly confirmed on the GSC. Lots of hydrothermal fields were discovered on the center and eastern GSC, while the western GSC has not been well investigated. During 17th Oct. to 9th Nov. 2009, the 3rd leg of Chinese DY115-21 cruise with R/V Dayangyihao has been launched along 2°N-5°S near equatorial East Pacific Rise (EPR). Two new hydrothermal fields were confirmed. One is named 'Precious Stone Mountain', which is the first hydrothermal field on the GM. The other is found at 101.47°W, 0.84°S EPR. The 'Precious Stone Mountain' hydrothermal field (at 101.49°W, 1.22°N) is located at an off-axial seamount on the southern GM boundary, with a depth from 1,450 to 1,700m. Hydrothermal fluids emitting from the fissures and hydrothermal fauna were captured by deep-tow video. Few mineral clasts of pyrite and chalcopyrite were separated from one sediment sample, but no sulfide chimney was found yet. Hydrothermal fauna such as alive mussels, crabs, shrimps, tubeworms, giant clams, as well as rock samples were collected by TV-Grab. The study of the seafloor classification with Simrad EM120 multi-beam echosounder has been conducted on the 'Precious Stone Mountain' hydrothermal field. The result indicates that seafloor materials around the hydrothermal field can be characterized into three types, such as the fresh lava, hydrothermal sediment, and altered rock.

  2. Borehole plugging by hydrothermal transport. Final report

    International Nuclear Information System (INIS)

    Calcium silicate--and aluminosilicate--compositions based on mixtures of fine grained quartz with various cements or calcium silicate compounds have been investigated under hydrothermal conditions in the temperature range 110-2500C and pressure range 1,000-10,000 psi, pressures which are always in excess of that required to maintain liquid H2O, and approximate the confining pressures which might be anticipated in deep boreholes. All silicate cement combinations investigated produce materials having adequate strength after reaction times of 1 day or longer. The calcium aluminate cement was also adequate with respect to strength but would need to be investigated more extensively for overall properties because of its highly reactive chemistry. The mini-rock cylinder-cement plug hydrothermal experiments in both limestone and sandstone resulted in reasonable magnitudes of bonding strength. The typical shear strength of a hydrothermally treated cement-sandstone plug is 1030 psi, and the compressive strength of the extruded cement plug is 9550 psi. Reactions having a potential for producing calcium carbonate plugs in holes drilled in carbonate rocks were studied. It should be noted that most cements are calcium silicate systems and are chemically compatible with the CaCO3 and CaMg(CO3)2 in the rock walls of the hole. A side benefit from this research is some insight into the suitability of massive carbonate rocks as disposal sites. Carbonate rocks by themselves are highly impermeable, have low exchange capacity, and a low water content--all properties that are desirable in the storage medium. A major drawback is the presence of secondary permeability in the form of solutionally modified joints, fractures, and bedding planes

  3. Porosity evolution in Icelandic hydrothermal systems

    Science.gov (United States)

    Thien, B.; Kosakowski, G.; Kulik, D. A.

    2014-12-01

    Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced hydrothermal systems, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal systems, grant number CRSII2_141843/1) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal systems. These are typically high enthalphy systems where a magmatic pluton is located at a few kilometers depth. These shallow plutons increase the geothermal gradient and trigger the circulation of hydrothermal waters with a steam cap forming at shallow depth. Field observations suggest that active and fossil Icelandic hydrothermal systems are built from a superposition of completely altered and completely unaltered layers. With help of 1D and 2D reactive transport models (OpenGeoSys-GEM code), we investigate the reasons for this finding, by studying the mineralogical evolution of protoliths with different initial porosities at different temperatures and pressures, different leaching water composition and gas content, and different porosity geometries (i.e. porous medium versus fractured medium). From this study, we believe that the initial porosity of protoliths and volume changes due to their transformation into secondary minerals are key factors to explain the different alteration extents observed in field studies. We also discuss how precipitation and dissolution kinetics can influence the alteration time scales.

  4. Vertical Cable Seismic Survey for Hydrothermal Deposit

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2012-04-01

    The vertical cable seismic is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. This type of survey is generally called VCS (Vertical Cable Seismic). Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. Our first experiment of VCS surveys has been carried out in Lake Biwa, JAPAN in November 2009 for a feasibility study. Prestack depth migration is applied to the 3D VCS data to obtain a high quality 3D depth volume. Based on the results from the feasibility study, we have developed two autonomous recording VCS systems. After we carried out a trial experiment in the actual ocean at a water depth of about 400m and we carried out the second VCS survey at Iheya Knoll with a deep-towed source. In this survey, we could establish the procedures for the deployment/recovery of the system and could examine the locations and the fluctuations of the vertical cables at a water depth of around 1000m. The acquired VCS data clearly shows the reflections from the sub-seafloor. Through the experiment, we could confirm that our VCS system works well even in the severe circumstances around the locations of seafloor hydrothermal deposits. We have, however, also confirmed that the uncertainty in the locations of the source and of the hydrophones could lower the quality of subsurface image. It is, therefore, strongly necessary to develop a total survey system that assures a accurate positioning and a deployment techniques

  5. Hydrothermal Liquefaction Treatment Preliminary Hazard Analysis Report

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, Peter P.; Wagner, Katie A.

    2015-08-31

    A preliminary hazard assessment was completed during February 2015 to evaluate the conceptual design of the modular hydrothermal liquefaction treatment system. The hazard assessment was performed in 2 stages. An initial assessment utilizing Hazard Identification and Preliminary Hazards Analysis (PHA) techniques identified areas with significant or unique hazards (process safety-related hazards) that fall outside of the normal operating envelope of PNNL and warranted additional analysis. The subsequent assessment was based on a qualitative What-If analysis. This analysis was augmented, as necessary, by additional quantitative analysis for scenarios involving a release of hazardous material or energy with the potential for affecting the public.

  6. Hydrothermal Synthesis of Platinum Group Metal Nanoparticles

    OpenAIRE

    Krehula, Stjepko; Musić, Svetozar

    2011-01-01

    A novel route for the synthesis of platinum group metal nanoparticles has been reported. The synthesis is based on the addition of tetramethylammonium hydroxide (TMAH) to the aqueous PtCl4, IrCl3 or Rh(NO3)3 solution followed by the hydrothermal treatment of these precipitation systems at 160 ºC. The mean size of nanoparticles was 9.2 nm for platinum, 21 nm for iridium, and 28 nm for rhodium. The average crystallite size was estimated at 7.4 nm for platinum, 3.1 nm for iridium and...

  7. Geomicrobiology of deep-sea hydrothermal vents.

    Science.gov (United States)

    Jannasch, H W; Mottl, M J

    1985-08-23

    During the cycling of seawater through the earth's crust along the mid-ocean ridge system, geothermal energy is transferred into chemical energy in the form of reduced inorganic compounds. These compounds are derived from the reaction of seawater with crustal rocks at high temperatures and are emitted from warm (chemosynthesis. Bacteria grow most abundantly in the shallow crust where upwelling hot, reducing hydrothermal fluid mixes with downwelling cold, oxygenated seawater. The predominant production of biomass, however, is the result of symbiotic associations between chemolithotrophic bacteria and certain invertebrates, which have also been found as fossils in Cretaceous sulfide ores of ophiolite deposits. PMID:17841485

  8. Caracterización detallada de la mineralización en veta Eureka, y su comparación con otras mineralizaciones del Distrito Cerro Negro, Macizo del Deseado, Santa Cruz, Argentina

    OpenAIRE

    Permuy Vidal, Conrado

    2014-01-01

    El distrito Cerro Negro está ubicado en el noroeste del Macizo del Deseado, a unos 50 km al sureste de la localidad de Perito Moreno, en la provincia de Santa Cruz (Patagonia, Argentina). Comprende un conjunto de mineralizaciones vetiformes epitermales de Au-Ag con reservas calculadas en 6,7 Moz Au eq., que posicionan actualmente a Cerro Negro como el más importante proyecto epitermal de oro y plata de la región y como uno de los más importantes descubrimientos epitermales a nivel mundial. En...

  9. Hydrothermal carbonization and torrefaction of grape pomace: a comparative evaluation.

    Science.gov (United States)

    Pala, Mehmet; Kantarli, Ismail Cem; Buyukisik, Hasan Baha; Yanik, Jale

    2014-06-01

    Grape pomace was treated by hydrothermal carbonization (sub-critical water, 175-275°C) and torrefaction (nitrogen atmosphere, 250 and 300°C), with mass yield of solid product (char) ranging between 47% and 78%, and energy densification ratio to 1.42-1.15 of the original feedstock. The chars were characterised with respect to their fuel properties, morphological and structural properties and combustion characteristics. The hydrothermal carbonization produced the char with greater energy density than torrefaction. The chars from torrefaction were found to be more aromatic in nature than that from hydrothermal carbonization. Hydrothermal carbonization process produced the char having high combustion reactivity. Most interesting was the finding that aqueous phase from hydrothermal carbonization had antioxidant activity. The results obtained in this study showed that HTC appears to be promising process for a winery waste having high moisture content. PMID:24709539

  10. Structure of the Wagner Basin in the Northern Gulf of California From Interpretation of Seismic Reflexion Data

    Science.gov (United States)

    Gonzalez, M.; Aguilar, C.; Martin, A.

    2007-05-01

    The northern Gulf of California straddles the transition in the style of deformation along the Pacific-North America plate boundary, from distributed deformation in the Upper Delfin and Wagner basins to localized dextral shear along the Cerro Prieto transform fault. Processing and interpretation of industry seismic data adquired by Petroleos Mexicanos (PEMEX) allow us to map the main fault structures and depocenters in the Wagner basin and to unravel the way strain is transferred northward into the Cerro Prieto fault system. Seismic data records from 0.5 to 5 TWTT. Data stacking and time-migration were performed using semblance coefficient method. Subsidence in the Wagner basin is controlled by two large N-S trending sub-parallel faults that intersect the NNW-trending Cerro Prieto transform fault. The Wagner fault bounds the eastern margin of the basin for more than 75 km. This fault dips ~50° to the west (up to 2 seconds) with distinctive reflectors displaced more than 1 km across the fault zone. The strata define a fanning pattern towards the Wagner fault. Northward the Wagner fault intersects the Cerro Prieto fault at 130° on map view and one depocenter of the Wagner basin bends to the NW adjacent to the Cerro Prieto fault zone. The eastern boundary of the modern depocenter is the Consag fault, which extends over 100 km in a N-S direction with an average dip of ~50° (up to 2s) to the east. The northern segment of the Consag fault bends 25° and intersects the Cerro Prieto fault zone at an angle of 110° on map view. The acoustic basement was not imaged in the northwest, but the stratigraphic succession increases its thickness towards the depocenter of the Wagner basin. Another important structure is El Chinero fault, which runs parallel to the Consag fault along 60 km and possibly intersects the Cerro Prieto fault to the north beneath the delta of the Colorado River. El Chinero fault dips at low-angle (~30°) to the east and has a vertical offset of about 0

  11. ANALISIS DEL CO-TRATAMIENTO PASIVO DE AGUAS RESIDUALES MUNICIPALES Y DRENAJE ACIDO DE MINAS EN CERRO RICO DE POTOSÍ, BOLIVIA

    Directory of Open Access Journals (Sweden)

    William H.J. Strosnider

    2015-01-01

    Full Text Available El drenaje acido de minas (DAM es un problema a nivel mundial. El co-tratamiento pasivo de DAM con aguas residuales municipales (ARM es una manera efectiva y de bajo costo que utiliza los nutrientes de ARM para tratar las concentraciones de metales y sulfato en DAM. Cerro Rico de Potosí, Bolivia es una de las grandes ciudades mineras en el mundo que tiene muchos problemas con el DAM. El objetivo de este estudio fue determinar velocidades de reacción de Al, Fe, Mn, Zn, y otros metales en DAM provenientes de un flujo de agua en Cerro Rico usando un sistema reactor de tres etapas. El DAM tenía un pH de 3.58, acidez de 1080 mg/L equivalente a CaCO3 conteniendo concentraciones de 12, 68, 17, y 550 mg/L de Al, Fe, Mn y Zn respectivamente. Las velocidades de reacción de Al, Fe, Mn y Zn fueron de 1.43, 2.09, 0.01 y 0.10 d-1, respectivamente.

  12. Enterramiento colectivo y metalurgia en el yacimiento Neolítico de Cerro Virtud (Cuevas de Almanzora, Almería

    Directory of Open Access Journals (Sweden)

    Montero Ruiz, Ignacio

    1996-12-01

    Full Text Available The rescue excavation of the Cerro Virtud (Almería, Spain, has shown new evidences that might change the traditional interpretations of the Neolithic period. This excavation has documented not only the first burials associated with an open air site but also pristine metallurgical activity within a Neolithic context. When first employed by archaeologists, the term ''Neolithic" implied a thechnological rather than an economic phenomenon. In this article we shall discuss the terminological implications of metal in order to understand the development of Neolithic in the Iberian Peninsula.

    La excavación de urgencia de Cerro Virtud (Almería, España ha documentado nuevos datos que permiten cambiar algunas de las interpretaciones tradicionales sobre el Neolítico. La aparición de un enterramiento colectivo en un yacimiento al aire libre, así como las primeras evidencias de actividad metalúrgica en contexto neolítico son las principales novedades. Se discuten las implicaciones que la aparición del metal supone para comprender el desarrollo del Neolítico en la Península Ibérica, teniendo en cuenta la fuerte carga tecnológica que predomina en el uso de ese término "Neolítico".

  13. TECNOLOGÍA Y SUBSISTENCIA EN EL SITIO ARQUEOLÓGICO CERRO TAPERA VÁZQUEZ (PARQUE NACIONAL PRE-DELTA, REPÚBLICA ARGENTINA

    Directory of Open Access Journals (Sweden)

    Mariano Bonomo

    2014-10-01

    Full Text Available In this paper the results of the studies carried out on ceramic and bone materials recorded at Cerro Tapera Vázquez site (Argentinean Northeast are presented. Taxonomic, anatomic and taphonomic studies of bone assemblages and technological-decorative analysis and refitting of pottery were undertaken. The site is located on a mound next to El Ceibo Creek, where 16 m2 were excavated in 2008. Abundant smooth, incised and modeled pottery (handles and zoomorphic appendages and numerous bones remains of Myocastor coypus (most frequent taxon, Blastocerus dichotomus, Ozotoceros bezoarticus, Cavia aperea, Leopardus geoffroyi, Lycalopex gymnocercus, Hydrochaeris hydrochaeris, birds and fish (Siluriformes and Characiformes were recorded. Except Cavia aperea rodent and Dusicyon gimnocercus fox, all taxa show evidence of anthropic modification (cut marks, fresh fractures and burning. Two radiocarbon dates were obtained: 650 and 520 yrs. BP. The results reached in this study lead to the conclusion that the pre-Hispanic populations that occupied Cerro Tapera Vázquez by the end of the Late Holocene were riverine canoe peoples, with complex ceramic technology and subsistence based on hunting of coypu, capybara and cervids, fishing and small-scale horticulture.

  14. Effect of artificial feeders on pollen loads of the hummingbirds of Cerro de la Muerte, Costa Rica.

    Science.gov (United States)

    Avalos, Gerardo; Soto, Alejandra; Alfaro, Willy

    2012-03-01

    Although sugar-water feeders are commonly used by enthusiasts to attract hummingbirds, little is known about how they affect hummingbird behavior and flower use. We studied the highland hummingbird assemblage of Cerro de La Muerte, Costa Rica, both at a site with permanent feeders (La Georgina Restaurant) and further from it. We examined how feeder use and monopolization affected seasonal changes in pollen loads during four sampling periods, including dry and wet seasons, from 2003-2005. We expected that species monopolizing the feeders would carry little or no pollen whatsoever, and would have pollen loads characterized by low floral diversity, in contrast with species less dependent on feeders. We obtained pollen samples from 183 individuals of four hummingbird species captured around the feeders using mist nets, which were compared with a pollen reference collection of plants with a pollination syndrome by hummingbirds. The same methods were implemented at a site 3km away from the feeders. Feeder usage was quantified by counting the number of times hummingbirds drank from the feeders in periods of 4min separated by 1min. The effects of hummingbird species and season on pollen load categories were assessed using a nominal logistic regression. The alpha species at the site, the Fiery-throated Hummingbird (Panterpe insignis), dominated the feeders during the dry season. Meanwhile, in the wet season, feeder usage was more evenly distributed across species, with the exception of the Volcano Hummingbird, Selasphorus flammula, which occupies the last place in the dominance hierarchy. Pollen loads of hummingbirds captured near feeders were low in abundance (more than 50% of captured individuals had zero or low pollen loads), and low in species richness (96% of the hummingbirds with pollen from only one plant genus, Centropogon). Overall pollen loads increased during the dry season coinciding with peaks in flower availability, although the majority of captured

  15. The ~ 2500 yr B.P. Chicoral non-cohesive debris flow from Cerro Machín Volcano, Colombia

    Science.gov (United States)

    Murcia, H. F.; Hurtado, B. O.; Cortés, G. P.; Macías, J. L.; Cepeda, H.

    2008-04-01

    Cerro Machín Volcano (CMV) is located in the central part of the Colombian Andes (2750 m asl), 150 km southwest of Bogotá. It is considered the most dangerous active volcano of Colombia. CMV has experienced at least six major explosive eruptions during the last 5000 years. These eruptions have emplaced many types of pyroclastic deposits with associated lahars that have traveled more than 100 km. One of these lahars is called Chicoral Debris Flow Deposit (DFD2). This deposit is exposed as discontinuous terraces (3-20 m thick) along the Coello and Magdalena rivers up to 109 km from the source. The DFD2 covers a minimum area of 62 km 2 and has a minimum volume of 0.57 km 3. It comprises two dacite-rich volcaniclastic units. Grain-size analysis reveals that the matrix content and sorting increase with distance while the average grain size decreases. The clay content of the DFD2 matrix is approximately 1%, thus categorizing it as a non-cohesive debris flow. Radiocarbon dates obtained from underlying and overlying paleosols yielded ages of 2505 + 65 and 1640 + 45 yr B.P., respectively. These dates suggest that DFD2 is related to the ~ 2600 yr B.P. El Guaico eruption of CMV. This eruption produced a block-and-ash flow that filled and blocked the Toche River up to 5 km from the volcano. Subsequent remobilization of this loose material by runoff water generated a massive debris flow that traveled 91 km along the Toche and Coello rivers and continued across the Espinal Alluvial Fan debouching into the Magdalena River where it continued another 18 km prior to its transformation into a sediment-laden flow. Because the last eruption of the volcano occurred ca. 900 years ago, no historic activity of CMV is known among inhabitants of the region. Hence the region has developed without awareness of volcanic hazards. Therefore an assessment of volcanic hazards is essential for understanding and evaluating the vulnerability and risk to which people are exposed in case of a future

  16. Reactive transport modeling of hydrothermal circulation in oceanic crust: effect of anhydrite precipitation on the dynamics of submarine hydrothermal systems

    Science.gov (United States)

    Yang, J.

    2009-12-01

    Hydrothermal fluid circulation represents an extremely efficient mechanism for the exchange of heat and matter between seawater and oceanic crust. Precipitation and dissolution of minerals associated with hydrothermal flow at ridge axes can alter the crustal porosity and permeability and hence influence the dynamics of hydrothermal systems. In this study, a fully coupled fluid flow, heat transfer and reactive mass transport model was developed using TOUGHREACT to evaluate the role of mineral precipitation and dissolution on the evolution of hydrothermal flow systems, with a particular attention focused on anhydrite precipitation upon heating of seawater in recharge zones and the resultant change in the crustal porosity and permeability. A series of numerical case studies were carried out to assess the effect of temperature and aqueous phase inflow concentrations on the reactive geochemical system. The impact of chemically induced porosity and permeability changes on the dynamics of hydrothermal systems was also addressed.

  17. Entropy Production in Convective Hydrothermal Systems

    Science.gov (United States)

    Boersing, Nele; Wellmann, Florian; Niederau, Jan

    2016-04-01

    Exploring hydrothermal reservoirs requires reliable estimates of subsurface temperatures to delineate favorable locations of boreholes. It is therefore of fundamental and practical importance to understand the thermodynamic behavior of the system in order to predict its performance with numerical studies. To this end, the thermodynamic measure of entropy production is considered as a useful abstraction tool to characterize the convective state of a system since it accounts for dissipative heat processes and gives insight into the system's average behavior in a statistical sense. Solving the underlying conservation principles of a convective hydrothermal system is sensitive to initial conditions and boundary conditions which in turn are prone to uncertain knowledge in subsurface parameters. There exist multiple numerical solutions to the mathematical description of a convective system and the prediction becomes even more challenging as the vigor of convection increases. Thus, the variety of possible modes contained in such highly non-linear problems needs to be quantified. A synthetic study is carried out to simulate fluid flow and heat transfer in a finite porous layer heated from below. Various two-dimensional models are created such that their corresponding Rayleigh numbers lie in a range from the sub-critical linear to the supercritical non-linear regime, that is purely conductive to convection-dominated systems. Entropy production is found to describe the transient evolution of convective processes fairly well and can be used to identify thermodynamic equilibrium. Additionally, varying the aspect ratio for each Rayleigh number shows that the variety of realized convection modes increases with both larger aspect ratio and higher Rayleigh number. This phenomenon is also reflected by an enlarged spread of entropy production for the realized modes. Consequently, the Rayleigh number can be correlated to the magnitude of entropy production. In cases of moderate

  18. Estudio petrográfico de las facies piroclásticas de la Formación Cerro Varela en el sur de la Sierra de San Luis

    Directory of Open Access Journals (Sweden)

    Amancay N. Martínez

    2010-11-01

    Full Text Available En la provincia de San Luis, existen tres sub-cuencas denominadas Las Salinas, Beazley y Mercedes. Estas cuencas corresponden a depocentros de rift elongados en sentido NO, que alojan rocas ígneas de edad triásica con espesores que llegan hasta los 4.000 metros. Las rocas ígneas de la Formación Cerro Varela forman parte del cerro homónimo que constituye los últimos asomos australes de la sierra de San Luis. Las riolitas triásicas que afloran en la sierra de Varela se disponen dentro de un esquema estructural extensional asociado a la formación de cuencas de tipo rift. Las unidades analizadas de la Formación Cerro Varela están compuestas por tobas cristalinas tanto de alto grado como de bajo grado de soldadura, de composición riolítica e interpretadas como depósitos originados por flujos piroclásticos. Por su litología, edad y contexto regional, las rocas de la Formación Cerro Varela integran el magmatismo gondwánico del Grupo Choiyoi de edad permotriásica de la Cordillera Frontal de Mendoza y San Juan.

  19. Deep-Sea Hydrothermal-Vent Sampler

    Science.gov (United States)

    Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.

    2008-01-01

    An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal vent at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal vents has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300 C), deep-sea hydrothermal- vent samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements. The apparatus (see figure) includes an intake equipped with a temperature probe, plus several other temperature probes located away from the intake. The readings from the temperature probes are utilized in conjunction with readings from flowmeters to determine the position of the intake relative to the hydrothermal plume and, thereby, to position the intake to sample directly from the plume. Because it is necessary to collect large samples of water in order to obtain sufficient microbial biomass but it is not practical to retain all the water from the samples, four filter arrays are used to concentrate the microbial biomass (which is assumed to consist of particles larger than 0.2 m) into smaller volumes. The apparatus can collect multiple samples per dive and is designed to process a total volume of 10 L of vent fluid, of which most passes through the filters, leaving a total possibly-microbe-containing sample volume of 200 mL remaining in filters. A rigid titanium nose at the intake is used for cooling the sample water before it enters a flexible inlet hose connected to a pump. As the water passes through the titanium nose, it must be cooled to a temperature that is above a mineral

  20. Hydraulic characterization of hydrothermally altered Nopal tuff

    International Nuclear Information System (INIS)

    Understanding the mechanics of variably saturated flow in fractured-porous media is of fundamental importance to evaluating the isolation performance of the proposed high-level radioactive waste repository for the Yucca Mountain site. Developing that understanding must be founded on the analysis and interpretation of laboratory and field data. This report presents an analysis of the unsaturated hydraulic properties of tuff cores from the Pena Blanca natural analog site in Mexico. The basic intent of the analysis was to examine possible trends and relationships between the hydraulic properties and the degree of hydrothermal alteration exhibited by the tuff samples. These data were used in flow simulations to evaluate the significance of a particular conceptual (composite) model and of distinct hydraulic properties on the rate and nature of water flow

  1. Geomicrobiology of Deep-Sea Hydrothermal Vents

    Science.gov (United States)

    Jannasch, Holger W.; Mottl, Michael J.

    1985-08-01

    During the cycling of seawater through the earth's crust along the midocean ridge system, geothermal energy is transferred into chemical energy in the form of reduced inorganic compounds. These compounds are derived from the reaction of seawater with crustal rocks at high temperatures and are emitted from warm (methane-, hydrogen-, iron-, and manganese-oxidizing bacteria have also been found. Methanogenic, sulfur-respiring, and extremely thermophilic isolates carry out anaerobic chemosynthesis. Bacteria grow most abundantly in the shallow crust where upwelling hot, reducing hydrothermal fluid mixes with downwelling cold, oxygenated seawater. The predominant production of biomass, however, is the result of symbiotic associations between chemolithotrophic bacteria and certain invertebrates, which have also been found as fossils in Cretaceous sulfide ores of ophiolite deposits.

  2. Evolutionary origins of hydrothermal vents metazoans

    Directory of Open Access Journals (Sweden)

    Samadi Sarah

    2015-01-01

    Full Text Available The discovery of the oases associated with hydrothermal vents in the deep sea, is probably the most fascinating discovery of oceanography of the last century. In this habitat, contrary to all expectations, a thriving development of unknown organisms was observed. At that time the knowledge about the deep sea organisms was very scarce and the accepted hypotheses about their evolutionary origins, their physiology or their ecology were very speculative. Almost forty years later, exploration of the deep-sea realm, but also of paleontological data together with the improvements in the phylogenetic methods, allowed the rejection of the hypothesis of an evolutionary history cut off the rest of the marine realm.

  3. Methane and radioactive isotopes in submarine hydrothermal systems

    International Nuclear Information System (INIS)

    This thesis consists of two parts: 1) methane and 2) radioactive isotopes, especially radon, in submarine hydrothermal systems. Both parts deal with the use of these gases as tracers for mapping hydrothermal vents at sea, and with their relationships to other sensitive tracers such as helium, manganese, and temperature. Hydrothermal methane was used as a real-time tracer for locating new submarine hydrothermal systems along spreading axes, discovering new hydrothermal systems at two locations in Pacific Ocean: 1) 200S on East Pacific Rise, and 2) Mariana Trough Back-arc Basin. Methane shows good correlations with helium-3 and temperature with similar ratios in various hydrothermal systems, 3 to 42 x 106 for the methane to helium-3 ratio, and 3 to 19 μ cc/kg0C for the methane to temperature anomaly. These similar ratios from different areas provide evidence for chemical homogeneity of submarine hydrothermal waters. A good correlation between methane and manganese appears to be associated only with high-temperature hydrothermal systems. Radioisotopes in the vent waters of 210N high-temperature hydrothermal system have end-member concentrations of 7.5 to 40 dpm/kg for Ra-226, 360 dpm/kg for Rn 222, 62 dpm/kg for Pb-210, and 19 dpm/kg for Po-210. The radon activity for this system is one order of magnitude lower, and the Pb-210 activity is one order or magnitude higher, than those a the low temperature Galapagos system. All these observations suggest that the high radon, and low Pb-210 activity observed in Galapagos system may originate from the extensive subsurface mixing and water-rock interaction in this system (direct injection of radon and scavenging of Pb-210)

  4. Chatkalita, nekrasovita y otros minerales del grupo de la estannita de Veta María Eugenia, Cerro Atajo, Catamarca Chatkalita, nekrasovita y otros minerales del grupo de la estannita de veta María Eugenia, Cerro Atajo, Catamarca

    Directory of Open Access Journals (Sweden)

    M. F. Márquez-Zavalía

    2007-06-01

    Full Text Available En veta María Eugenia, Cerro Atajo, Catamarca, se encontró una asociación de minerales de estaño integrada por: chatkalita Cu6Fe2+Sn2S8, nekrasovita Cu26V2(Sn,As,Sb6S32, colusita Cu26V2(As,Sn,Sb6S32, kësterita Cu2(Zn,FeSnS4 y estannoidita Cu8(Fe,Zn3Sn2S12. Estos minerales, incluidos en watanabeíta, están acompañados principalmente por pirita, esfalerita, calcopirita, tetraedrita, bornita y galena; aikinita, enargita, luzonita, marcasita, arsenopirita y pirrotina participan como minerales accesorios. Chatkalita se presenta en agregados irregulares de hasta 40 µm, asociados con kësterita y estannoidita, es de color rosa-anaranjado claro, birreflectante y anisótropa, con colores de polarización pardos; su composición química (% en peso es: S=29,76-30,37, Fe=4,53-7,92, Cu=39,13-43,21, Zn=0,75-5,53, As=0,19- 2,42, Sn=15,27-20,50 y Sb=0,00-0,32. Nekrasovita es isótropa, de color pardo con leve tinte rosa-violáceo y está asociada con estannoidita; su composición química es: S=30,29-30,63, Fe=3,41-4,75, Cu=44,26-45,70, Zn=0,56-1,00, As=4,18-4,71, Sn=12,53-13,64 y Sb=0,71- 0,77. Colusita es pardo amarillenta, isótropa, se presenta como parches irregulares y cintas discontinuas en tennantita; su composición química es: S=30,59-30,74, Fe=2,18-3,58, Cu=47,22-48,13, Zn=0,21-0,64, As=6,38-6,61, Sn=9,04-9,33 y Sb=0,49-1,66. Kësterita es pardo grisácea, con débil birreflectancia y anisotropía y colores de polarización pardos, a menudo se presenta bordeada por chatkalita; su composición química es: S=28,68-29,14, Fe=1,98-2,14, Cu=31,06-32,51, Zn=9,03-11,57 y Sn=26,39-27,03. Estannoidita es de color castaño, pleocroica (castaño-rosado a pardo-grisáceo y anisótropa con colores de polarización pardos y pardo-amarillentos, ocurre en parches irregulares y como bandas bordeando tennantita; su composición química es: S=29,11-29,83, Fe=8,45-10,30, Cu=38,05-41,01, Zn=3,18-4,90, y Sn=15,84-18,94. La reflectividad y dureza de pulido de

  5. Hydrothermal growth of ZnO nanostructures - revew article

    Directory of Open Access Journals (Sweden)

    Sunandan Baruah and Joydeep Dutta

    2009-01-01

    Full Text Available One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attractive for its simplicity and environment friendly conditions. This review summarizes the conditions leading to the growth of different ZnO nanostructures using hydrothermal technique. Doping of ZnO nanostructures through hydrothermal method are also highlighted.

  6. Al Este del Cerro Pampa: ampliación del área de disponibilidad de obsidiana de la Pampa del Asador (Provincia de Santa Cruz East of the Cerro Pampa: enlargement of the obsidian availability area from Pampa del Asador (Santa Cruz Province

    Directory of Open Access Journals (Sweden)

    Juan Bautista Belardi

    2006-12-01

    Full Text Available La Pampa del Asador ha sido identificada como el lugar de proveniencia de distintos tipos de obsidiana, mayoritariamente negra, y el Cerro Pampa, ubicado en el extremo suroeste de la pampa, ha sido un punto central a partir del cual se ha medido la dispersión de los artefactos confeccionados en esta materia prima. Sobre la base de la interpretación de imágenes satelitales, análisis químicos y trabajos de campo se presenta y discute la evidencia provista por nódulos y artefactos de obsidiana recuperados en paleocauces y un abanico aluvial que se origina en la Pampa del Asador. Los resultados muestran la ampliación del área de disponibilidad de obsidiana 65 km hacia el este y 75 km al noreste del Cerro Pampa y, aunque presentando menor frecuencia relativa de nódulos y el decrecimiento de sus tamaños, el área se amplía a lo largo de la Pampa La Chispa. Estos resultados tienen implicaciones tanto en términos de la distribución de frecuencias de artefactos de obsidiana en el registro arqueológico regional como en los costos de aprovisionamiento de la roca.Pampa del Asador has been identified as the source of distinct types of obsidian (generally black, and Cerro Pampa, located in the extreme southwest of the Pampas, has been the central point from which the dispersal of artifacts fashioned from this obsidian has been measured. Based on the interpretation of satellite images, geochemical analysis, and field work, we present and discuss evidence provided by nodules and artifacts of obsidian recovered from paleo-drainage channels and an alluvial fan which originates in Pampa del Asador. The results expand the area of availability of obsidian 65 km east and 75 km northeast of Cerro Pampa, and also across Pampa La Chispa, although the relative frequency of nodules decreases and smaller size increases. These results have implications both in terms of the distribution and frequency of obsidian artifacts in the regional archaeological record

  7. Evolución petrotectónica del distrito minero Cerro Áspero y modelo de emplazamiento de los depósitos wolframíferos, Córdoba Petrotectonic evolution of the Cerro Aspero mining district and emplacement model of the wolframiferous deposits, Córdoba

    OpenAIRE

    D. Mutti; S. González Chiozza

    2005-01-01

    La geología relacionada con la intrusión granítica Cerro Áspero expone en el faldeo oriental de la sierra de Comechingones, mineralización metalífera diseminada y en brechas hidráulicas, conectada genéticamente a un grupo minero integrado por un sistema de enjambres de venas, vetas y mantos cuarzosos con direcciones NNO, ONO y N. La comarca presenta polimetamorfismo y al menos, dos eventos de cizallamiento simple (D3 y D4) y estructuras penetrativas (S2, S3 y S4) que se desarrollaron desde el...

  8. ANÁLISIS DE MACRORRESTOS VEGETALES EN EL SITIO ARQUEOLÓGICO LOS TRES CERROS 1 (ISLA LAS MORAS, VICTORIA, ENTRE RÍOS) / Macroremains plant analysis on the Tres Cerros 1 archaeological site (Las Moras island, Victoria, Entre Ríos).

    OpenAIRE

    María de los Milagros Colobig; Jorge Omar Sánchez; Alejandro Fabián Zucol

    2015-01-01

    El presente trabajo es la primera aproximación al estudio de macrorrestos botánicos en el sitio Los Tres Cerros 1 (isla Las Moras, Victoria, Entre Ríos). Estos restos fueron recuperados mediante la técnica de flotación manual. A partir del material extraído, se exploró el rol de los recursos vegetales y su importancia en la subsistencia en los grupos humanos que habitaron el Delta Superior del río Paraná durante el Holoceno tardío. Se identificaron cinco familias: Solanaceae, Chenopodiaceae, ...

  9. CARACTERIZACIÓN FLORÍSTICA Y ESTRUCTURAL DEL BOSQUE SECO TROPICAL DEL CERRO TASAJERO, SAN JOSÉ DE CÚCUTA (NORTE DE SANTANDER), COLOMBIA FLORISTIC AND STRUCTURAL CHARACTERIZATION OF THE TROPICAL DRY FOREST CERRO TASAJERO, SAN JOSE DE CÚCUTA (NORTE DE SANTANDER), COLOMBIA

    OpenAIRE

    Merly Carrillo-Fajardo; Orlando Rivera-Díaz; Roberto Sánchez-Montaño

    2007-01-01

    Se analiza la composición y estructura florística de 0,1 hectárea de bosque seco tropical del Cerro Tasajero, mediante el método propuesto por Gentry, como modificación se registran además individuos con DAP ³ 1 cm. Los resultados de riqueza, al considerar los elementos con DAP ³ 2,5 cm, presentan 281 individuos agrupados en 30 familias, 46 géneros y 60 especies; al añadir los elementos con DAP entre 1 y 2,5 cm (204 individuos), se registran los siguientes valores de diversidad (34 familias, ...

  10. Base hydrolysis and hydrothermal processing of PBX-9404

    International Nuclear Information System (INIS)

    Base hydrolysis in combination with hydrothermal processing has been proposed as an environmentally acceptable alternative to open burning/open detonation for degradation and destruction of high explosives. In this report, the authors examine gaseous and aqueous products of base hydrolysis of the HMX-based plastic bonded explosive, PBX-9404. They also examined products from the subsequent hydrothermal treatment of the base hydrolysate. The gases produced from hydrolysis of PBX-9404 are ammonia, nitrous oxide, and nitrogen. Major aqueous products are sodium formate, acetate, nitrate, and nitrite, but not all carbon products have been identified. Hydrothermal processing of base hydrolysate destroyed up to 98% of the organic carbon in solution, and higher destruction efficiencies are possible. Major gas products detected from hydrothermal processing were nitrogen and nitrous oxide

  11. Microbiological production and ecological flux of northwestern subduction hydrothermal systems

    Science.gov (United States)

    Sunamura, M.; Okamura, K.; Noguchi, T.; Yamamoto, H.; Fukuba, T.; Yanagawa, K.

    2012-12-01

    Deep-sea hydrothermal system is one of the most important sources for heat and chemical flux from the oceanic crust to the global ocean. The rich biological community around the hydrothermal vent shows chemolithoautotrophic microbial production are important in deep sea ecosystems. More than 99% of microbiological available chemical components in hydrothermal vent fluid, e.g. sulfide, methane, hydrogen, Fe2+, and Mn2+, is released into surrounding seawater to construct hydrothermal plume, suggesting that the chemolithoautotrophic-microbial primary production in the hydrothermal plume is huge and important in the whole hydrothermal ecosystems. To understand the impact of hydrothermal plume to a microbial ecosystem and a connectivity with zooplankton, we targeted and investigated a total of 16 hydrothermal fileds (7 sites in Okinawa trough, 3 sites in Ogasawara arc, and 6 sites in Mariana arc and back arc) and investigated in several cruises under the TAIGA project in Japan. Hydrothermal fluids in the subduction system are rich in sulfide. The hydrothermal fluids in the Okinawa trough, Ogasawara arc. and Mariana trough are characterized by rich in methane, poor in other reduced chemicals, and rich in iron, respectively. The major microbial composition was a potential sulfur oxidizing microbes SUP05 in the plume ecosystems, while an aerobic methanotrophic bacteria was secondary major member in methane-rich hydrothermal systems in Okinawa trough. Microbial quantitative and spatial distribution analyses of each plume site showed that the microbial population size and community structures are influenced by original chemical components of hydrothermal fluid, e.g. sulfide, methane and iron concentration. Microbial quantitative data indicated the removal/sedimentation of microbial cells from the plume and effect of phase separation in a same vent field through construction of gas-rich or gas-poor plumes. After the correlation of plume mixing effect, we estimates that the

  12. Direct use of hydrothermal energy: a review of environmental aspects

    Energy Technology Data Exchange (ETDEWEB)

    O' Banion, K.; Layton, D.

    1981-08-28

    The potential environmental impacts of the exploration, development, and production of hydrothermal geothermal energy for direct use applications are reviewed and evaluated. Mitigation strategies and research and development needs are included. (MHR)

  13. Whole Algae Hydrothermal Liquefaction: 2014 State of Technology

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Susanne B.; Zhu, Yunhua; Snowden-Swan, Lesley J.; Anderson, Daniel; Hallen, Richard T.; Schmidt, Andrew J.; Albrecht, Karl O.; Elliott, Douglas C.

    2014-07-30

    This report describes the base case yields and operating conditions for converting whole microalgae via hydrothermal liquefaction and upgrading to liquid fuels. This serves as the basis against which future technical improvements will be measured.

  14. Hydrothermal synthesis of vanadium oxide nanotubes by a facile route

    Institute of Scientific and Technical Information of China (English)

    HUANG Chunming; LIU Xueqin; KONG Lingbin; ZHOU Haijia; LIU Yaqiang; QIU Jiawen; WANG Yinyue

    2006-01-01

    Vanadium oxide nanotubes were synthesized by hydrothermal treatment from V2O5·nH2O sols as precursor and dodecylamine as structure-directing template. The morphology and structure of the nanotubes were characterized by SEM, TEM, XRD, TG-DTA and FTIR. The experimental results reveal that the duration of the hydrothermal treatment is of importance for obtaining Vox-NTs which have a layered structure. TG-DTA study indicates that V5+ cations in nanotubes are partially reduced to V4+ cations. The results from FTIR spectra indicate the difference in V-O vibrations between before and after hydrothermal treatment. From the results, it suggests that during hydrothermal treatment, the rearrangement of the vanadium oxide structure leads to the formation of VOx nanotubes from lamellar structure because of the presence of V4+ species.

  15. Radionuclides in hydrothermal systems as indicators of repository conditions

    International Nuclear Information System (INIS)

    Hydrothermal systems in tuffaceous and older sedimentary rocks contain evidence of the interaction of radionuclides in fluids with rock matrix minerals and with materials lining fractures, in settings somewhat analogous to the candidate repository site at Yucca Mountain, NV. Earlier studies encompassed the occurrences of U and Th in a ''fossil'' hydrothermal system in tuffaceous rock of the San Juan Mountains volcanic field, CO. More recent and ongoing studies examine active hydrothermal systems in calderas at Long Valley, CA and Valles, NM. At the Nevada Test Site, occurrences of U and Th in fractured and unfractured rhyolitic tuff that was heated to simulate the introduction of radioactive waste are also under investigation. Observations to date suggest that U is mobile in hydrothermal systems, but that localized reducing environments provided by Fe-rich minerals and/or carbonaceous material concentrate U and thus attenuate its migration. 11 refs., 6 figs., 1 tab

  16. A data processing method for MAPR hydrothermal plume tur-bidity data and its application in the Precious Stone Mountain hydrothermal field

    Institute of Scientific and Technical Information of China (English)

    CHEN Sheng; TAO Chunhui; LI Huaiming; CHEN Yongshun; ZHOU Jianping; WU Tao

    2014-01-01

    Hydrothermal plume is an important constituent of seabed hydrothermal circulation and is also one of the characteristics of active hydrothermal vents. Portable Miniature Autonomous Plume Recorders (MAPR) attached to a towed deep-sea instrument was used to search for hydrothermal plumes and hydrothermal vents. We introduced the basic principle of MAPR based on deep towing technology to detect plumes, then analyzed the factors affecting the quality of the MAPR data and presented a data correction method for MAPR, including instrument location correction, noise reduction processing, system error elimination and seawater background reduction. Finally we applied the method to analyze MAPR data obtained during the Chinese DY115-21 cruise on R/VDayang Iin the “Precious Stone Mountain” hydrothermal field on the Gala-pagos Microplate. The results provided a better understanding of the distribution of the hydrothermal activ-ity in this field, indicating the presence of a new hydrothermal vent.

  17. Chemical environments of submarine hydrothermal systems. [supporting abiogenetic theory

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    The paper synthesizes diverse information about the inorganic geochemistry of submarine hydrothermal systems, provides a description of the fundamental physical and chemical properties of these systems, and examines the implications of high-temperature, fluid-driven processes for organic synthesis. Emphasis is on a few general features, i.e., pressure, temperature, oxidation states, fluid composition, and mineral alteration, because these features will control whether organic synthesis can occur in hydrothermal systems.

  18. The magnetic signature of hydrothermal systems in slow spreading environments

    Science.gov (United States)

    Tivey, Maurice A.; Dyment, Jérôme

    Slow spreading mid-ocean ridges like the Mid-Atlantic Ridge host a remarkable diversity of hydrothermal systems including vent systems located on the neovolcanic axis, large axial volcanoes, in transform faults and nontransform offsets, and associated with low-angle detachment faults, now recognized as a major tectonic feature of slow spreading environments. Hydrothermal systems are hosted in various lithologies from basalt to serpentinized peridotite and exposed lower oceanic crust. The substantial variations of hydrothermal processes active in these environments have important implications for the magnetic structure of oceanic crust and upper mantle. Hydrothermal processes can both destroy the magnetic minerals in basalt, diabase, and gabbro and create magnetic minerals by serpentinization of ultramafic rocks and deposition of magnetic minerals. We report on the diversity of magnetic anomaly signatures over the vent systems at slow spreading ridges and show that the lateral scale of hydrothermal alteration is fundamentally a local phenomenon. This highly focused process leads to magnetic anomalies on the scale of individual vent fields, typically a few hundreds of meters or less in size. To detect such features, high-resolution, near-bottom magnetic surveys are required rather than sea surface surveys. High-resolution surveys are now more tractable with deep-towed systems, dynamically positioned ships, and with the recent development of autonomous underwater vehicles, which allow detailed mapping of the seafloor on a scale relevant to hydrothermal activity. By understanding these present-day active hydrothermal systems, we can explore for yet to be discovered buried deposits preserved off-axis, both to determine past history of hydrothermal activity and for resource assessment.

  19. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases

    OpenAIRE

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K.G.; Wiegand, Simone

    2016-01-01

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007) Proc Natl Acad Sci USA 104(22):9346−9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores...

  20. Novel technology for hydrothermal treatment of NPP evaporator concentrates

    International Nuclear Information System (INIS)

    A novel technology was developed for treatment of evaporator concentrates produced as a result of operation of evaporation devices comprising the main component of special water purification systems of nuclear power plants (NPP). The developed technology includes a hydrothermal (T=250-300 deg. C and P=80-120 bar) processing of evaporator concentrates in oxidation medium in order to destruct stable organic complexes of cobalt radionuclides and remove these radionuclides by oxide materials formed during such a processing. The cesium radionuclides contained in evaporator concentrates are removed by a conventional method-through application of one of the developed composite sorbents with ferrocyanides of transition metals used as active agents. Extensive laboratory studies of the processes occurring in evaporator concentrates under hydrothermal conditions were performed. It was shown that hydrothermal oxidation of evaporator concentrates has a number of advantages as compared to traditional oxidation methods (ozonization, photo-catalytic, electrochemical and plasma oxidation). A laboratory installation was built for the flow-type hydrothermal oxidation of NPP evaporator concentrates. The obtained experimental results showed good prospects for the developed method application. On the basis of the results obtained, a pilot installation of productivity up to 15 l/hour was developed and built in order to work out the technology of evaporator concentrates hydrothermal treatment. The pilot tests of the hydrothermal technology for evaporator concentrates hydrothermal treatment were performed for 6 months in 2006 at the 1. reactor unit of the Novovoronezhskaya NPP (Voronezh Region, Russia). Optimal technological regimes were determined, and estimations of the economic soundness of the technology were made. The advantages of the presented technology in terms of management of concentrated liquid radioactive wastes (LRW) at nuclear cycle facilities, as compared to other methods

  1. Exploring hydrothermal reactions : from prebiotic synthesis to green chemistry

    OpenAIRE

    Kopetzki, Daniel

    2011-01-01

    In this thesis chemical reactions under hydrothermal conditions were explored, whereby emphasis was put on green chemistry. Water at high temperature and pressure acts as a benign solvent. Motivation to work under hydrothermal conditions was well-founded in the tunability of physicochemical properties with temperature, e.g. of dielectric constant, density or ion product, which often resulted in surprising reactivity. Another cornerstone was the implementation of the principles of green chemis...

  2. Health assessment for Lehigh Portland Cement Company, Mason City, Cerro Gordo County, Iowa, Region 10. CERCLIS No. IAD005288634. Preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    1989-08-29

    The Lehigh Portland Cement Company Site is listed by the U.S. Environmental Protection Agency (EPA) on the National Priorities List (NPL). The site consists of approximately 150 acres and is located in the west side of U.S. Highway 65, in the northern section of Mason City, Cerro Gordo County, Iowa. Seven groundwater samples were analyzed together with 1 field blank (E E/FIT). No significant levels of contaminants were found in the private wells except for sodium (23 mg/1) from one residential well of unknown depth. The contaminants of concern are: arsenic, cadmium, lead, sodium, and sulfates. The site is considered to be of public health concern because of the risk resulting from potential exposure to hazardous substances via soil, surface water, groundwater and air.

  3. Approaching viscosity control: electrical heating of extra heavy oil as alternative to diluent injection in down hole in Cerro Negro Field, Faja Petrolifera del Orinoco

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Manuel [Petroleos de Venezuela SA, PDVSA (Venezuela)

    2011-07-01

    Electrical heating is a method used to enhance oil recovery in extra heavy oil reservoirs. This method can be used when diluent injection or other methods are not able to reduce oil viscosity sufficiently or when problems of product quality or quantity arise. The aim of this paper is to evaluate the performance of electrical heating, individually and simultaneously with injection of diluents. For this purpose, simulations were undertaken in one well with integrated electrical heating and diluent injection in Cerro Negro Field in the Orinoco oil belt, Venezuela. Results have shown that the application of both methods together is more profitable than the application of electrical heating alone. This paper demonstrated that the use of electrical heating and diluent injection combined is a valid alternative to diluent injection alone, reducing production loss.

  4. La minería hidráulica romana desarrollada en el Cerro del Sol (Granada) para explotar sus recursos auríferos

    OpenAIRE

    García-Pulido, Luis José

    2008-01-01

    [ES] La Alhambra se encuentra asentada en el extremo más occidental de un depósito aluvial con el nombre de Cerro del Sol. En este promontorio, que actúa como elemento separador entre las cuencas de los ríos Darro y Genil, está atestiguada la existencia de oro, encontrándose presente en el Conglomerado Alhambra. Con la romanización se inició la explotación a gran escala de los recursos auríferos del sudeste de la península Ibérica, haciendo uso de diversas técnicas propias de la minería hidrá...

  5. Cambios vegetacionales antropogénicos en el Cerro Catedral (Río Negro, Argentina) Human impact and vegetation change in Mt. Catedral (Río Negro, Argentina)

    OpenAIRE

    ALEJANDRO DEZZOTTI; LUIS SANCHOLUZ; MARTIN NAUMANN

    2004-01-01

    En el sector septentrional de la ladera Este del cerro Catedral (41°10’S, 71°30’O, 2.388 m) la práctica del esquí comenzó hace alrededor de 65 años y en la actualidad se desarrolla el centro de deportes invernales más importante de Sudamérica. Se compararon los tipos de vegetación actual y potencial a partir de mapas y fotografías históricas, fotografías aéreas actuales, mapas climáticos y topográficos y la estructura del bosque. La vegetación actual está representada por i) la pradera (10,7%...

  6. Cosmic ray observations at Chacaltaya and Cerro la Negra combined with the Pierre Auger and Milagro observatories: GRBs and search for cosmic ray correlations

    International Nuclear Information System (INIS)

    We consider the possibility to search for cosmic ray phenomena time correlated among distant experiments that are currently running in the world. In particular we consider the correlations of events detected by four experiments: between Milagro, operating in USA, and Cerro La Negra Cosmic Ray Laboratory, under construction in Mexico, and between Chacaltaya, in Bolivia, and Auger Observatory, under construction in Argentina. Almost complete sky coverage with fairly uniform celestial exposure of the northern and the southern hemispheres by the above four experiments at the same time could provide important information on astrophysical phenomena. Search for Gamma Ray Bursts and search for non random coincidence between these experiments seem to be feasible under an international extensive air shower joint experiment with the main goal to watch GRBs and other astrophysical phenomena

  7. Analysis of lateritic material from Cerro Impacto by instrumental neutron activation employing a low-energy photon semiconductor and a high-energy Ge(Li) detector

    International Nuclear Information System (INIS)

    Nineteen elements were determined in four different grain size fractions of a bulk geological material from Cerro Impacto for a study of the physical (mechanical) concentration process of different elements based upon the hardness of the different minerals. The analysis was performed by excitation of the sample with a high, slow neutron flux followed by gamma-ray spectroscopy with both a conventional Ge(Li) high-energy detector and a low-energy photon detector (LEPD). The accuracy of this method was studied with the use of two standard reference materials, SY-2 and SY-3, which are similar to the real samples. The values determined were also compared with a secondary target x-ray fluorescence method for all the elements that were suitable to both methods. Actually, the x-ray fluorescence method was found to be more complementary than competitive. 10 refs., 2 figs., 4 tabs

  8. Justificación y diseño de falsa protección diferencial de barras para S.E Cerro de la Plata

    OpenAIRE

    Feliz Juárez, Javier Fernando

    2009-01-01

    La finalidad de nuestro proyecto es el diseño y justificación de un sistema de protección de barras de alimentación de 45 kV para la subestación eléctrica blindada de “Cerro de la Plata” (Madrid), propiedad de la compañía eléctrica Unión Fenosa Distribución. La particularidad de este diseño radica en la consecución de un sistema de protección de barras de subestación que cumpla las exigencias básicas de los sistemas de protección, sin la utilización de un relé de protección ded...

  9. Edades K/Ar al este del cerro Nahuel Pan, Chubut. Implicancias en la correlacion del Grupo Divisadero y del Choiyoi en el área

    Directory of Open Access Journals (Sweden)

    M.E. Vattuone

    2004-09-01

    Full Text Available Al este del cerro Nahuel Pan, existe una secuencia lávico piroclástica que se apoya en discordancia angular sobre una serie volcánica de composición basandesítica. Se dataron por el método K/Ar, la facies lávica dacítico-andesitica y las volcanitas basandesíticas, obteniéndose edades de 105 ± 5 Ma y de 252 ± 10 Ma respectivamente, lo que ubica a las primeras en el Cretácico, en la base del Miembro Superior del Grupo Divisadero y a las segundas en el Permotriásico, siendo equivalentes en edad al Grupo Choiyoi. Por primera vez se comprueba a esta latitud, en el faldeo oriental del área andina, la presencia de volcanitas pertenecientes a este grupo.

  10. Hydrothermal iron flux variability following rapid sea level changes

    Science.gov (United States)

    Middleton, Jennifer L.; Langmuir, Charles H.; Mukhopadhyay, Sujoy; McManus, Jerry F.; Mitrovica, Jerry X.

    2016-04-01

    Sea level changes associated with Pleistocene glacial cycles have been hypothesized to modulate melt production and hydrothermal activity at ocean ridges, yet little is known about fluctuations in hydrothermal circulation on time scales longer than a few millennia. We present a high-resolution record of hydrothermal activity over the past 50 ka using elemental flux data from a new sediment core from the Mir zone of the TAG hydrothermal field at 26°N on the Mid-Atlantic Ridge. Mir sediments reveal sixfold to eightfold increases in hydrothermal iron and copper deposition during the Last Glacial Maximum, followed by a rapid decline during the sea level rise associated with deglaciation. Our results, along with previous observations from Pacific and Atlantic spreading centers, indicate that rapid sea level changes influence hydrothermal output on mid-ocean ridges. Thus, climate variability may discretize volcanic processing of the solid Earth on millennial time scales and subsequently stimulate variability in biogeochemical interactions with volcanic systems.

  11. Effect of hydrothermal treatment of coal on its associative structure

    Energy Technology Data Exchange (ETDEWEB)

    Shui Heng-fu; Wang Zhi-cai; Wang Gao-qiang; Niu Min-feng [Anhui University of Technology, Maanshan (China). School of Chemistry & Chemical Engineering

    2006-10-15

    4 bituminous coals with different ranks were thermally and hydrothermally treated under different conditions, and the raw and treated coals were extracted with carbon disulfide/N-2-pyrrolidinone (CS{sub 2}/NMP) mixed solvent (1:1 by volume). It is found that the extraction yields of the thermal or hydrothermal treated coals at proper conditions increase in different extent. The increments of extraction yields for hydrothermal treated coals are higher than those of thermal treated coals. FT-IR shows that the adsorption peaks at 3410 cm{sup -1} attributed to OH group for the hydrothermal treated coals decrease, suggesting the dissociation of the coal aggregation structure due to the breakage of hydrogen bonds, resulting in the increase of extraction yields for the treated coals. For higher rank coal, the removal of minerals and the dissociation of {pi}-cation association after hydrothermal treatment of coal may be responsible for the increase of extraction yield. In addition, the mechanism of hydrothermal treatment of coal was discussed. 15 refs., 2 figs., 5 tabs.

  12. Biosphere in 3.5 Ga submarine hydrothermal system

    International Nuclear Information System (INIS)

    Abundant organic matter (kerogen) was identified in ∼3.5 Ga hydrothermal silica dikes from the North Pole area in the Pilbara craton, Western Australia. The silica dikes developed in the uppermost 1000 m of the ancient oceanic crust. Thus, they would have been deposited in the 3.5 Ga sub-seafloor hydrothermal system. The carbon and nitrogen isotopic compositions of the kerogen were analyzed in this study. Their highly 13C-depleted isotopic compositions (δ13C = -38 to -33 per mille) strongly suggest that they are originally derived from biologically produced organic matter. The remarkable similarity of the δ13C values between the kerogen and modern hydrothermal vent organisms may suggest that the kerogen was derived from chemoautotrophic organisms. This idea is also consistent with their nitrogen isotopic compositions (δ15N = -4 to +4 per mille). The silica dikes consist mainly of fine-grained silica with minor pyrite and sphalerite. These mineral assemblages indicate that the silica dike was deposited from relatively low-temperature (probably less than 150degC) reducing hydrothermal fluid. Thus, anaerobic thermophilic/hyperthermophilic organisms could have survived in the hydrothermal fluid, which formed the silica dikes. Therefore, it is plausible that a chemoautotrophic-based biosphere (possibly methanogenesis) probably existed in the Early Archean sub-seafloor hydrothermal system. (author)

  13. Hydrothermal processing of inorganic components of Hanford tank sludge

    International Nuclear Information System (INIS)

    Hydrothermal Processing (HTP) is an attractive approach for the treatment of Hanford tank sludge. Hydrothermal Processing refers to a waste treatment technique in which an aqueous waste stream is fed through a chemical reactor at elevated temperatures and pressures to effect desired chemical transformations and separations. Transformations such as organic and nitrate destruction and sludge reformulation have been demonstrated at pilot scale using simulants of Hanford tank wastes. At sufficiently high temperatures and pressures organics and nitrates are destroyed in seconds, producing primarily simple products such as CO32-, H2O, N2, N2O and OH-, and sludges are reduced in volume and reformulated as rapid settling oxides amenable to downstream separation, or in some cases reformulated as soluble products. This report describes the hydrothermal dissolution of chromium and chromium oxide; the hydrothermal oxidation of chromium with nitrate; hydrothermal dissolution of aluminum-bearing sludges; the solubility of aluminum compounds in caustic hydrothermal media; experimental techniques for the study of solubility and phase behavior; optical cell studies of basic aluminate solution solubilities; and high temperature, low density salt solubility in the packed-bed flow apparatus

  14. Evolución magmática del Granito Peñón Rosado, Cerro Asperecito, flanco occidental de la sierra de Famatina

    Directory of Open Access Journals (Sweden)

    J.A. Dahlquist

    2006-03-01

    Full Text Available El granate es un mineral accesorio poco común en rocas ígneas y constituye un tema relevante de la petrología ígnea. Estudios combinados de petrología, química mineral, geoquímica de roca total y geoquímica isotópica en el cerro Asperecito indican que los granitoides con granate que forman el Granito Peñón Rosado (GPR fueron producidos por la fusión parcial de rocas metasedimentarias con subsecuente diferenciación durante su emplazamiento en el Ordovícico inferior-medio. En este sentido, la facies GPR1 representa un cristalizado temprano, la facies GPR2 representa un fundido diferenciado, y la facies GPR3 un fundido residual. El Granito Peñón Rosado, fue emplazado en condiciones de moderada temperatura (785ºC y presión media (4,4 kb en profundidades de la corteza media (~15 km. El emplazamiento casi sincrónico en la corteza media de una abundante suite metaluminosa durante el Ordovícico inferior-medio (468 Ma en el cerro Asperecito fue suficiente para inducir anatexis local de los metasedimentos circundantes. Los contenidos de elementos mayoritarios (CaO, Na2O y elementos traza (Rb, Sr, Ba en el Granito Peñón Rosado sugieren anatexis a partir de un material inmaduro acumulado en un plataforma continental. Así, el Granito Peñón Rosado es un típico granitoide tipo-S con granate y el modelo establecido aquí puede contribuir a un mejor entendimiento acerca de la cristalización del granate en rocas graníticas.

  15. Hydrothermal evolution of repository groundwaters in basalt

    International Nuclear Information System (INIS)

    Groundwaters in the near field of a radioactive waste repository in basalt will change their chemical composition in response to reactions with the basalt. These reactions will be promoted by the heat generated by the decaying waste. It is important to predict both the rate and the extent of these reactions, and the secondary minerals produced, because the alteration process controls the chemical environment affecting the corrosion of the canister, the solubility and complexation of migrating radionuclides, the reactivity of the alteration products to radionuclides sorption, and the porosity and permeability of the host rock. A comprehensive review of the literature leads to the preliminary finding that hydrothermally altering basalts in geothermal regions such as Iceland lead to a secondary mineralogy and groundwater composition similar to that expected to surround a repository. Furthermore, laboratory experiments replicating the alteration conditions approximate those observed in the field and expected in a repository. Preliminary estimates were made of the rate of hydration and devitrification of basaltic glass and the zero-order dissolution rate of basaltic materials. The rates were compared with those for rhyolitic glasses and silicate minerals. Preliminary calculations made of mixed process alteration kinetics, involving pore diffusion and surface reaction suggest that at temperatures greater than 1500C, alteration proceeds so rapidly as to become pervasive in normally fractured basalt exposed to higher temperatures in the field. 70 references

  16. Hydrothermal Gasification for Waste to Energy

    Science.gov (United States)

    Epps, Brenden; Laser, Mark; Choo, Yeunun

    2014-11-01

    Hydrothermal gasification is a promising technology for harvesting energy from waste streams. Applications range from straightforward waste-to-energy conversion (e.g. municipal waste processing, industrial waste processing), to water purification (e.g. oil spill cleanup, wastewater treatment), to biofuel energy systems (e.g. using algae as feedstock). Products of the gasification process are electricity, bottled syngas (H2 + CO), sequestered CO2, clean water, and inorganic solids; further chemical reactions can be used to create biofuels such as ethanol and biodiesel. We present a comparison of gasification system architectures, focusing on efficiency and economic performance metrics. Various system architectures are modeled computationally, using a model developed by the coauthors. The physical model tracks the mass of each chemical species, as well as energy conversions and transfers throughout the gasification process. The generic system model includes the feedstock, gasification reactor, heat recovery system, pressure reducing mechanical expanders, and electricity generation system. Sensitivity analysis of system performance to various process parameters is presented. A discussion of the key technological barriers and necessary innovations is also presented.

  17. Catalytic hydrothermal liquefaction of water hyacinth.

    Science.gov (United States)

    Singh, Rawel; Balagurumurthy, Bhavya; Prakash, Aditya; Bhaskar, Thallada

    2015-02-01

    Thermal and catalytic hydrothermal liquefaction of water hyacinth was performed at temperatures from 250 to 300 °C under various water hyacinth:H2O ratio of 1:3, 1:6 and 1:12. Reactions were also carried out under various residence times (15-60 min) as well as catalytic conditions (KOH and K2CO3). The use of alkaline catalysts significantly increased the bio-oil yield. Maximum bio-oil yield (23 wt%) comprising of bio-oil1 and bio-oil2 as well as conversion (89%) were observed with 1N KOH solution. (1)H NMR and (13)C NMR data showed that both bio-oil1 and bio-oil2 have high aliphatic carbon content. FTIR of bio-residue indicated that the usage of alkaline catalyst resulted in bio-residue samples with lesser oxygen functionality indicating that catalyst has a marked effect on nature of the bio-residue and helps to decompose biomass to a greater extent compared to thermal case. PMID:25240515

  18. Additive effects of acetic acid upon hydrothermal reaction of amylopectin

    International Nuclear Information System (INIS)

    It is well known that over 0.8 kg kg−1 of starch is consisted of amylopectin (AP). In this study, production of glucose for raw material of ethanol by hydrothermal reaction of AP as one of the model compound of food is discussed. Further, additive effects of acetic acid upon hydrothermal reactions of AP are also investigated. During hydrothermal reaction of AP, production of glucose occurred above 453 K, and the glucose yield increased to 0.48 kg kg−1 at 473 K. Upon hydrothermal reaction of AP at 473 K, prolongation of the holding time was not effective for the increase of the glucose yield. Upon hydrothermal reaction of AP at 473 K for 0 s, the glucose yield increased significantly by addition between 0.26 mol L−1 and 0.52 mol L−1 of acetic acid. However, the glucose yield decreased and the yield of the other constituents increased with the increases of concentration of acetic acid from 0.65 mol L−1 to 3.33 mol L−1. It was considered that hydrolysis of AP to yield glucose was enhanced due to the increase of the amount of proton derived from acetic acid during hydrothermal reaction with 0.52 mol L−1 of acetic acid. -- Highlights: ► Glucose production by hydrothermal reaction of amylopectin (AP) at 473 K. ► Glucose yield increased to 0.48 kg kg-1 at 473 K. ► Prolongation of holding time was not effective for glucose yield. ► Glucose yield increased significantly by acetic acid (0.26–0.52 mol L-1) addition. ► Hydrolysis of AP to glucose was enhanced due to increase of proton from acetic acid.

  19. Environmental benefits from hydro-thermal coordination

    International Nuclear Information System (INIS)

    Individual hydro- and thermal dominated electric power systems often have characteristics which make coordination between such systems inherently desirable. Operation- and design related differences call for interconnecting the two types of systems, e.g. by a 'pump-storage type' interplay between them. In this scheme the hydro-system can provide for required additional peak power and the necessary 'profiles' of production, while the thermal system covers new energy demand by increased energy production on the course of off-peak hours. Since energy represents one of the crucial building blocks in a modern society, all considerations concerning the development of coordinated systems of first of all focused on the functions and the economics efficiency of these systems and second on the technical solutions that have been developed. However, people have realized that they are part of a larger picture and that their well-being cannot be separated from that of nature. Power production from fossil burning and energy used can give about significant adverse environmental effects through emission into atmosphere of SO2, NOx, CO2, and particulates. The environmental aspects has more or less been neglected in the coordination process. Therefore the time in ripe to extend the discussion to include also environmental effects. The true least-cost solution to the utility operation- and planning problem can only be found by a consistent treatment of environmental effects in all steps of this problem. The paper gives an overview of the problem and demonstrates the environmental benefits from hydro-thermal coordination. (Author)

  20. Effects of process parameters on hydrothermal carbonization

    Science.gov (United States)

    Uddin, Md. Helal

    In recent years there has been increased research activity in renewable energy, especially upgrading widely available lignicellulosic biomass, in a bid to counter the increasing environmental concerns related with the use of fossil fuels. Hydrothermal carbonization (HTC), also known as wet torrefaction or hot water pretreatment, is a process for pretreatment of diverse lignocellulosic biomass feedstocks, where biomass is treated under subcritical water conditions in short contact time to produce high-value products. The products of this process are: a solid mass characterized as biochar/biocoal/biocarbon, which is homogeneous, energy dense, and hydrophobic; a liquid stream composed of five and six carbon sugars, various organic acids, and 5-HMF; and a gaseous stream, mainly CO2. A number of process parameters are considered important for the extensive application of the HTC process. Primarily, reaction temperature determines the characteristics of the products. In the solid product, the oxygen carbon ratio decreases with increasing reaction temperature and as a result, HTC biochar has the similar characteristics to low rank coal. However, liquid and gaseous stream compositions are largely correlated with the residence time. Biomass particle size can also limit the reaction kinetics due to the mass transfer effect. Recycling of process water can help to minimize the utility consumption and reduce the waste treatment cost as a result of less environmental impact. Loblolly pine was treated in hot compressed water at 200 °C, 230 °C, and 260 °C with 5:1 water:biomass mass ratio to investigate the effects of process parameters on HTC. The solid product were characterized by their mass yields, higher heating values (HHV), and equilibrium moisture content (EMC), while the liquid were characterized by their total organic carbon content and pH value.

  1. Hydrothermal alteration favoring phreatic eruption processes at Solfatara (Campi Flegrei)

    Science.gov (United States)

    Mayer, Klaus; Scheu, Bettina; Montanaro, Cristian; Aßbichler, Donjá; Isaia, Roberto; Dingwell, Donald B.

    2015-04-01

    Solfatara and Pisciarelli fumaroles are the main surface manifestations of the strong hydrothermal activity within the Campi Flegrei caldera system and pointing to a significant risk for phreatic eruptions in this densely populated area. Phreatic eruptions, triggered by various processes are hardly predictable in occurrence time and size. Despite their hazard potential, these eruptions, as well as the influence of hydrothermal alteration on their likelihood, magnitude and style, have so far been largely overlooked in experimental volcanology. The physical properties and the mechanical behavior of volcanic rocks are highly dependent on their original magmatic microstructure and on any eventual alteration of those microstructures due to hydrothermal reactions. We have therefore investigated the potential effects of hydrothermal alteration on rock microstructure and, as a consequence, on fragmentation dynamics. Rock samples from the vicinity of the Solfatara and Pisciarelli fumaroles have been characterized 1) geochemically (X-ray fluorescence, X-ray diffraction), 2) physically (density, porosity, permeability and elastic wave velocity) and 3) mechanically (uniaxial compressive strength, tensile strength). We furthermore have investigated the effects of hydrothermal alteration on fragmentation processes using a shock-tube apparatus, operating with Argon gas, water vapor and superheated water at temperatures up to 400°C and maximum pressures of 20 MPa. Fragmentation and ejection dynamics in the presence of three different energy sources within the pores have been investigated: overpressure by 1) Argon gas; or 2) water vapor and due to 3) steam flashing of superheated water. Fragmentation speed, fragmentation efficiency and fragmented particle ejection velocity were measured. Our results indicate on the one hand, that steam flashing provides the highest energy - resulting in increased fragmentation speed and particle ejection velocity and also a significant higher

  2. Variability in the microbial communities and hydrothermal fluid chemistry at the newly discovered Mariner hydrothermal field, southern Lau Basin

    Science.gov (United States)

    Takai, Ken; Nunoura, Takuro; Ishibashi, Jun-Ichiro; Lupton, John; Suzuki, Ryohei; Hamasaki, Hiroshi; Ueno, Yuichiro; Kawagucci, Shinsuke; Gamo, Toshitaka; Suzuki, Yohey; Hirayama, Hisako; Horikoshi, Koki

    2008-06-01

    A newly discovered hydrothermal field called the Mariner field on the Valu Fa Ridge in the southern Lau Basin was explored and characterized with geochemical and microbiological analyses. The hydrothermal fluid discharging from the most vigorous vent (Snow Chimney, maximum discharge temperature 365°C) was boiling at the seafloor at a depth of 1908 m, and two distinct end-member hydrothermal fluids were identified. The fluid chemistry of the typical Cl-enriched and Cl-depleted hydrothermal fluids was analyzed, as was the mineralogy of the host chimney structures. The variability in the fluid chemistry was potentially controlled by the subseafloor phase-separation (vapor loss process) and the microbial community activities. Microbial community structures in three chimney structures were investigated using culture-dependent and -independent techniques. The small subunit (SSU) rRNA gene clone analysis revealed that both bacterial and archaeal rRNA gene communities on the chimney surfaces differed among three chimneys. Cultivation analysis demonstrated significant variation in the culturability of various microbial components among the chimneys, particularly of thermophilic H2-oxidizing (and S-oxidizing) chemolithoautotrophs such as the genera Aquifex and Persephonella. The physical and chemical environments of chimney surface habitats are still unresolved and do not directly extrapolate the environments of possible subseafloor habitats. However, the variability in microbial community found in the chimneys also provides an insight into the different biogeochemical interactions potentially affected by the phase separation of the hydrothermal fluids in the subseafloor hydrothermal habitats. In addition, comparison with other deep-sea hydrothermal systems revealed that the Mariner field microbial communities have unusual characteristics.

  3. Hydrothermal and magmatic couplings at mid-ocean ridges : controls on the locations of high-temperature hydrothermal vent fields

    Science.gov (United States)

    Fontaine, Fabrice; Rabinowicz, Michel; Cannat, Mathilde; Escartin, Javier

    2013-04-01

    The heat output and thermal regime of oceanic spreading centers are strongly controlled by boundary layer processes between the hydrothermal system and the underlying crustal magma chamber, which remain to be fully understood. In thermal models, the dynamical interactions between the hydrothermal system and the deeper part of the lithosphere affected by processes such as magma chamber convection, magma crystallization and latent heat release, or simple conduction, is usually not considered and a ad-hoc temperature or heat flux is prescribed at the base of the hydrothermal layer. In this work we develop original two-dimensional numerical models of the interactions between a shallow cellular hydrothermal (porous) system at temperatures hydrothermal fields such as those discovered along the East Pacific Rise at 9°50'N or along the Juan de Fuca ridge/Endeavour segment for example. One hypothesis is that these fields require the formation of "elongated" hydrothermal convection cells that cool the crust on 5-10 kms, but the processes controlling the formation of such large aspect ratio (length/height) are poorly constrain. Our models show that such cells naturally arise from the dynamical coupling between a « low-viscosity », convecting lower-crust and a low-permeability upper hydrothermal layer. They also predict along-axis variations in the depth of the axial magma lens (AMC) seismic reflector of fast- and intermediate-spreading axes, and constrain lower oceanic crust cooling rates. They also suggest a dynamic link between upper oceanic crust along-axis permeability variations and stresses due to lower crust magmatic flow. We discuss the likelihood of this range of viscosity and permeability using available oceanic and ophiolites constraints and suggest that our work can motivate and help design future deep-sea experiments (e.g., drilling…).

  4. Concerns of Hydrothermal Degradation in CAD/CAM Zirconia

    Science.gov (United States)

    Kim, J.-W.; Covel, N.S.; Guess, P.C.; Rekow, E.D.; Zhang, Y.

    2010-01-01

    Zirconia-based restorations are widely used in prosthetic dentistry; however, their susceptibility to hydrothermal degradation remains elusive. We hypothesized that CAD/CAM machining and subsequent surface treatments, i.e., grinding and/or grit-blasting, have marked effects on the hydrothermal degradation behavior of Y-TZP. CAD/CAM-machined Y-TZP plates (0.5 mm thick), both with and without subsequent grinding with various grit sizes or grit-blasting with airborne alumina particles, were subjected to accelerated aging tests in a steam autoclave. Results showed that the CAD/CAM-machined surfaces initially exhibited superior hydrothermal degradation resistance, but deteriorated at a faster rate upon prolonged autoclave treatment compared with ground and grit-blasted surfaces. The accelerated hydrothermal degradation of CAD/CAM surfaces is attributed to the CAD/CAM machining damage and the absence of surface compressive stresses in the fully sintered material. Clinical relevance for surface treatments of zirconia frameworks in terms of hydrothermal and structural stabilities is addressed. PMID:19966039

  5. The hydrothermal synthesis of ceramic powders. Ph. D. Thesis

    Energy Technology Data Exchange (ETDEWEB)

    Krijgsman, P.

    1992-01-01

    The history of the hydrothermal synthesis is summarized and an appropriate definition of hydrothermal processing and its associated conditions is described. The chronological development of the present large scale process as it is now in operation in the factory in Sulitjelma (Norway) is described. The development of this production process covers both the mechanical and chemical engineering disciplines. The synthesis of xonotlite is considered. This focuses on the chemistry, the solubility characteristics and the thermodynamics of the appropriate raw materials. The effect of substitutions in the xonotlite lattice, and the batch production of xonotlite are highlighted and the chemical and physical properties of the materials concerned are discussed. The hydrothermal preparation of magnesium aluminum oxide as a precursor to be used for further processing, is discussed. The hydrothermal formation of barium titanate which is used in the microelectronic industry for disc and tubular capacitors is outlined. Concluding remarks with respect to the hydrothermal route with its inherent advantages over other production methods are given. The process however, is confined to the production of oxidic materials only due to the reaction medium used. The patent protection of the developed process is considered, and a theoretical appraisal of an insulated pipe support made of high density xonotlite, its advantages and inherent cost savings, is made.

  6. Metallogenesis of rich uranium deposits in Xiangshan hydrothermal ore field

    International Nuclear Information System (INIS)

    Xiangshan Uranium Ore field located in Jiangxi Province, south of China, is one of the largest volcanogenic hydrothermal uranium ore fields in China. There are apparent difference in uranium metallogenesis between low-grade deposits and rich uranium ones (U > 0.3%, especially U > 1%) in Xiangshan hydrothermal uranium ore field. The special hydrothermal solution with higher content of P, Ti, K elements is a geochemical controlling factor for rich uranium mineralization. Fluorine is an important transporter for uranium migration in hydrothermal system, however, it plays a limited function of uranium mineralization. In fact, uranium and thorium are migrated and precipitated through some complicated processes including alkali-metasomatism, co-migration, colloid co-precipitation with phosphate minerals and gas reduction etc., which has been proved by field investigation, experiments and a number of analysis. The deeper the orebodies are located, the higher the grade of ore is. The reasonable explanation is as following: (1) the contents of P, Ti, F, K. U and reducing gases in hydrothermal solution increase along with deepness; (2) The temperature and pressure in deep are higher than that on shallower parts. All the factors mentioned above together play active roles in uranium enrichment. Some suggestions for further exploitation and exploration in Xiangshan area have been put forward

  7. Impact-generated Hydrothermal Activity at the Chicxulub Crater

    Science.gov (United States)

    Kring, D. A.; Zurcher, L.; Abramov, O.

    2007-05-01

    Borehole samples recovered from PEMEX exploration boreholes and an ICDP scientific borehole indicate the Chicxulub impact event generated hydrothermal alteration throughout a large volume of the Maya Block beneath the crater floor and extending across the bulk of the ~180 km diameter crater. The first indications of hydrothermal alteration were observed in the crater discovery samples from the Yucatan-6 borehole and manifest itself in the form of anhydrite and quartz veins. Continuous core from the Yaxcopoil-1 borehole reveal a more complex and temporally extensive alteration sequence: following a brief period at high temperatures, impact- melt-bearing polymict breccias and a thin, underlying unit of impact melt were subjected to metasomatism, producing alkali feldspar, sphene, apatite, and magnetite. As the system continued to cool, smectite-series phyllosilicates appeared. A saline solution was involved. Stable isotopes suggest the fluid was dominated by a basinal brine created mostly from existing groundwater of the Yucatan Peninsula, although contributions from down-welling water also occurred in some parts of the system. Numerical modeling of the hydrothermal system suggests circulation occurred for 1.5 to 2.3 Myr, depending on the permeability of the system. Our understanding of the hydrothermal system, however, is still crude. Additional core recovery projects, particularly into the central melt sheet, are needed to better evaluate the extent and duration of hydrothermal alteration.

  8. Magma to Microbe: Modeling Hydrothermal Processes at Ocean Spreading Centers

    Science.gov (United States)

    Lowell, Robert P.; Seewald, Jeffrey S.; Metaxas, Anna; Perfit, Michael R.

    Hydrothermal systems at oceanic spreading centers reflect the complex interactions among transport, cooling and crystallization of magma, fluid circulation in the crust, tectonic processes, water-rock interaction, and the utilization of hydrothermal fluids as a metabolic energy source by microbial and macro-biological ecosystems. The development of mathematical and numerical models that address these complex linkages is a fundamental part the RIDGE 2000 program that attempts to quantify and model the transfer of heat and chemicals from "mantle to microbes" at oceanic ridges. This volume presents the first "state of the art" picture of model development in this context. The most outstanding feature of this volume is its emphasis on mathematical and numerical modeling of a broad array of hydrothermal processes associated with oceanic spreading centers. By examining the state of model development in one volume, both cross-fertilization of ideas and integration across the disparate disciplines that study seafloor hydrothermal systems is facilitated. Students and scientists with an interest in oceanic spreading centers in general and more specifically in ridge hydrothermal processes will find this volume to be an up-to-date and indispensable resource.

  9. Geologic evolution of the Lost City Hydrothermal Field

    Science.gov (United States)

    Denny, Alden R.; Kelley, Deborah S.; Früh-Green, Gretchen L.

    2016-02-01

    The Lost City Hydrothermal Field (LCHF) is a novel serpentinite-hosted vent field located on the Atlantis Massif southern wall. Results of 2 m resolution bathymetry, side scan, and video and still imagery, integrated with direct submersible observations provide the first high-resolution geologic map of the LCHF. These data form the foundation for an evolutionary model for the vent system over the past >120,000 years. The field is located on a down-dropped bench 70 m below the summit of the massif. The bench is capped by breccia and pelagic carbonate deposits underlain by variably deformed and altered serpentinite and gabbroic rocks. Hydrothermal activity is focused at the 60 m tall, 100 m across, massive carbonate edifice "Poseidon," which is venting 91°C fluid. Hydrothermal activity declines south and west of the Poseidon complex and dies off completely at distances greater than 200 m. East of Poseidon, the most recent stage of hydrothermal flow is characterized by egress of diffuse fluids from narrow fissures within a low-angle, anastomosing mylonite zone. South of the area of current hydrothermal activity, there is evidence of two discrete previously unrecognized relict fields. Active venting sites defined by carbonate-filled fissures that cut the carbonate cap rock at the summit of the massif mark the present-day northernmost extent of venting. These spatial relationships reflect multiple stages of field development, the northward migration of venting over time, and the likely development of a nascent field at the massif summit.

  10. Hydrothermal acid treatment for sugar extraction from Golenkinia sp.

    Science.gov (United States)

    Choi, Sun-A; Choi, Won-Il; Lee, Jin-Suk; Kim, Seung Wook; Lee, Gye-An; Yun, Jihyun; Park, Ji-Yeon

    2015-08-01

    In this study, hydrothermal acid treatment for efficient recovery of sugar from Golenkinia sp. was investigated. The initial glucose and XMG (xylose, mannose, and galactose) contents of a prepared Golenkinia sp. solution (40g/L) were 15.05 and 5.24g/L, respectively. The microalgal cell walls were hydrolyzed, for sugar recovery, by enzymatic saccharification and/or hydrothermal acid treatment. Among the various hydrothermal acid treatment conditions, the most optimal were the 2.0% H2SO4 concentration at 150°C for 15min, under which the glucose- and XMG-extraction yields were 71.7% and 64.9%, respectively. By pH 4.8, 50°C enzymatic hydrolysis after optimal hydrothermal acid treatment, the glucose- and XMG-extraction yields were additionally increased by 8.3% and 0.8%, respectively. After hydrothermal acid treatment, the combination with the enzymatic hydrolysis process improved the total sugar yield of Golenkinia sp. to 75.4%. PMID:25976916

  11. Reinterpretacion estratigráfica y petrología de la Formacion Chuscho, Precordillera de La Rioja Stratigraphical reinterpretation and petrology of the Cerro Chuscho Formation. Precordillera of La Rioja

    Directory of Open Access Journals (Sweden)

    L.E. Fauqué

    2003-06-01

    Full Text Available En la Precordillera de Jagüé (provincia de la Rioja, fueron agrupados bajo la denominación de Andesita Cerro Chuscho los afloramientos de volcanitas de: Punta del Agua, Cerro Chuscho y Las Casitas. Se consideraba a estas rocas comagmáticas, constituyendo el cerro Chuscho un cono subvolcánico heterogéneo compuesto por una autobrecha de flujo, integrada por rocas calcoalcalinas correspondientes al ciclo precordillerano. En este trabajo se asigna a los afloramientos del cerro Chuscho (Formación Chuscho como un complejo de volcanitas máficas intraordovícicas, representado por diques y filones de diabasas y por basaltos de estructura almohadillada. Conforman una facies ofiolítica asociada con las sedimentitas ordovícicas y, por lo tanto, quedarían incluidas en la Faja Ofiolítica Famatiniana, asociada a la apertura de un rift oceánico de cuenca marginal formado durante la acreción de Chilenia en el Cambro-Ordovícico. Sus características parecen cambiar a lo largo del rift, pasando de N-Morb en la Cordillera Frontal a E-Morb (P-MORB en la Precordillera de San Juan y La Rioja; estas diferentes características se deben muchas veces al cambio de elevación del rift respecto del manto. Por su parte, las Andesitas Punta del Agua (Formación Punta del Agua, son andesitas orogénicas de arco volcánico, de acuerdo a sus características geoquímicas, con edades que irían desde el Carbonífero superior al Pérmico inferior.In the region of Precordillera of Jagüe, in La Rioja province, the Palaeozoic volcanic rocks, known as the Punta del Agua, Cerro Chuscho and Las Casitas formations, have been grouped into one unit, the "Andesita Cerro Chuscho". These rocks have been considered to be comagmatic and to form a subvolcanic complex of autoclastic breccias and calc-alkaline lava flows of the precordilleran orogenic cycle. In our study, the Cerro Chuscho Formation is reinterpreted as a mafic volcanic complex. Of Ordovician, it includes dykes

  12. Versatile hydrothermal synthesis of one-dimensional composite structures

    Science.gov (United States)

    Luo, Yonglan

    2008-12-01

    In this paper we report on a versatile hydrothermal approach developed to fabricate one-dimensional (1D) composite structures. Sulfur and selenium formed liquid and adsorbed onto microrods as droplets and subsequently reacted with metallic ion in solution to produce nanoparticles-decorated composite microrods. 1D composites including ZnO/CdS, ZnO/MnS, ZnO/CuS, ZnO/CdSe, and FeOOH/CdS were successfully made using this hydrothermal strategy and the growth mechanism was also discussed. This hydrothermal strategy is simple and green, and can be extended to the synthesis of various 1D composite structures. Moreover, the interaction between the shell nanoparticles and the one-dimensional nanomaterials were confirmed by photoluminescence investigation of ZnO/CdS.

  13. Hydrothermal electrocatalytic oxidation for the treatment of herbicides wastewater.

    Science.gov (United States)

    Xiao, Hanshuang; Lv, Baoying; Gao, Junxia; Zhao, Guohua

    2016-05-01

    A hydrothermal electrocatalytic oxidation (HTECO) method is adopted to treat the biorefractory and toxic 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides wastewater on nano-Pt/Ti electrode in the existence of H2O2. Comparisons for the removal of 2,4-D and total organic carbon (TOC) have been carried out between HTECO with individual electrochemical oxidation (EO) and hydrothermal catalytic oxidation (HTCO), showing that high mineralization efficiency was obtained in HTECO process. The possible factors resulting in the high removal efficiency in HTECO process have been studied by investigating the properties of the electrode and solution in hydrothermal condition, the amount of active radicals, the decay kinetic, and evolution of main intermediates of 2,4-D. Thus, an enhanced mechanism for HTECO method for the treatment of herbicides wastewater has been obtained. PMID:26865489

  14. Coordination Hydrothermal Interconnection Java-Bali Using Simulated Annealing

    Science.gov (United States)

    Wicaksono, B.; Abdullah, A. G.; Saputra, W. S.

    2016-04-01

    Hydrothermal power plant coordination aims to minimize the total cost of operating system that is represented by fuel costand constraints during optimization. To perform the optimization, there are several methods that can be used. Simulated Annealing (SA) is a method that can be used to solve the optimization problems. This method was inspired by annealing or cooling process in the manufacture of materials composed of crystals. The basic principle of hydrothermal power plant coordination includes the use of hydro power plants to support basic load while thermal power plants were used to support the remaining load. This study used two hydro power plant units and six thermal power plant units with 25 buses by calculating transmission losses and considering power limits in each power plant unit aided by MATLAB software during the process. Hydrothermal power plant coordination using simulated annealing plants showed that a total cost of generation for 24 hours is 13,288,508.01.

  15. Application of cultural algorithm to generation scheduling of hydrothermal systems

    International Nuclear Information System (INIS)

    The daily generation scheduling of hydrothermal power systems plays an important role in the operation of electric power systems for economics and security, which is a large scale dynamic non-linear constrained optimization problem. It is difficult to solve using traditional optimization methods. This paper proposes a new cultural algorithm to solve the optimal daily generation scheduling of hydrothermal power systems. The approach takes the water transport delay time between connected reservoirs into consideration and can conveniently deal with the complicated hydraulic coupling simultaneously. An example is used to verify the correctness and effectiveness of the proposed cultural algorithm, comparing with both the Lagrange method and the genetic algorithm method. The simulation results demonstrate that the proposed algorithm has rapid convergence speed and higher solution precision. Thus, an effective method is provided to solve the optimal daily generation scheduling of hydrothermal systems

  16. Fractionation of Boron Isotopes in Icelandic Hydrothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, J.K.; Palmer, M.R.

    1995-01-01

    Boron isotope ratios have been determined in a variety of different geothermal waters from hydrothermal systems across Iceland. Isotope ratios from the high temperature meteoric water recharged systems reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal systems exhibit more positive {delta}{sup 11}B values than the meteoric water recharged geothermal systems. Water/rock ratios can be assessed from boron isotope ratios in the saline hydrothermal systems. Low temperature hydrothermal systems also exhibit more positive {delta}{sup 11}B than the high temperature systems, indicating fractionation of boron due to adsorption of the lighter isotope onto secondary minerals. Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the systems.

  17. Chemical reaction path modeling of hydrothermal processes on Mars: Preliminary results

    Science.gov (United States)

    Plumlee, Geoffrey S.; Ridley, W. Ian

    1992-01-01

    Hydrothermal processes are thought to have had significant roles in the development of surficial mineralogies and morphological features on Mars. For example, a significant proportion of the Martian soil could consist of the erosional products of hydrothermally altered impact melt sheets. In this model, impact-driven, vapor-dominated hydrothermal systems hydrothermally altered the surrounding rocks and transported volatiles such as S and Cl to the surface. Further support for impact-driven hydrothermal alteration on Mars was provided by studies of the Ries crater, Germany, where suevite deposits were extensively altered to montmorillonite clays by inferred low-temperature (100-130 C) hydrothermal fluids. It was also suggested that surface outflow from both impact-driven and volcano-driven hydrothermal systems could generate the valley networks, thereby eliminating the need for an early warm wet climate. We use computer-driven chemical reaction path calculation to model chemical processes which were likely associated with postulated Martian hydrothermal systems.

  18. Effects of hydrothermal treatment on the properties of nanoapatite crystals

    Directory of Open Access Journals (Sweden)

    Liang W

    2012-09-01

    Full Text Available Wei Liang,1,* Yunfei Niu,2,* Shuhua Ge,1 Shaojun Song,2 Jiacan Su,2 Zhuojing Luo11Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, People’s Republic of China; 2Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai, People’s Republic of China*These authors contributed equally to this workAbstract: We report the synthesis of nanoapatite crystals via a hydrothermal reaction of hydroxyapatite precipitates. The impact of the reaction conditions on the properties of the crystals obtained were evaluated. The hydrothermal reaction that takes place markedly affected the crystallinity, morphology, and size of the nanoapatite crystals formed. High crystallinity and large crystal size were obtained at higher hydrothermal temperatures and longer hydrothermal reaction times. The nanoapatite crystals were needle-like when prepared under ambient pressure conditions and rod-like when prepared under increased pressure. The crystals prepared at ambient pressure had a larger aspect ratio compared with those prepared under increased pressure. The aging time of the initial hydroxyapatite precipitate significantly affected growth of the nanoapatite crystals. With other hydrothermal reaction conditions being equal, the fresh hydroxyapatite precipitate produced notably larger crystals than the aged hydroxyapatite precipitate. The influence of apatite morphology on osteoblast viability was studied by MTT assay. The results indicate that the rod-like apatite showed a better biological response than needle-like apatite in promoting cell growth. Transmission electron microscopy showed that large quantities of needle apatite entered into cells and damaged their morphology.Keywords: nanoapatite crystals, hydrothermal treatment, morphology, cell viability

  19. Hydrothermal synthesis as a route to mineralogically-inspired structures.

    Science.gov (United States)

    McMillen, Colin D; Kolis, Joseph W

    2016-02-21

    The use of high temperature hydrothermal reactions to prepare crystals having mineralogically-related structures is described. Complex naturally occurring minerals can have fascinating structures and exhibit important features like low dimensionality, noncentrosymmetry, or ion channels that can provide excellent guideposts for the designed synthesis of new materials. Actual minerals, even though they may have intriguing physical properties, are often unsuitable for study because of the persistent impurities inevitably present in natural samples. Hydrothermal fluids at relatively high temperatures provide access to large, high quality single crystals of structures with mineral-like structures. This enables the study of physical properties like ionic conduction, magnetic spin frustration and non-linear optical behavior. Some fundamental considerations of the hydrothermal technique are discussed in the context of synthesizing mineralogically-inspired materials. The metal vanadates provide a surprisingly rich and diversified range of compounds and are selected to illustrate many of the concepts described here. A series of low dimensional mineral analogs featuring isolated units, chains, and layers have been prepared in the laboratory as large single crystals using a high temperature hydrothermal synthetic methods, and their physical properties are under investigation. The metal silicates are also highlighted as another promising field of exploration, since their hydrothermal synthesis surprisingly lags behind the enormous literature of the natural silicate minerals. The introduction of heteroelements, such as boron to make borosilicates, appears to also open the door to additional new materials. Many of these new materials have direct equivalents in the mineral kingdom, while others have no known analogs but are reminiscent of minerals and can be classified in the same ways. From these initial results there appears to be a very rich vein of synthetic minerals waiting

  20. Mecanismo de inserción del Laboratorio Tecnológico del Uruguay en el Parque Tecnológico Industrial del Cerro

    Directory of Open Access Journals (Sweden)

    Laura Márquez

    2011-05-01

    Full Text Available El Laboratorio Tecnológico del Uruguay, LATU, teniendo en cuenta su misión: "Impulsar el desarrollo sustentable del país y su inserción internacional a través de la innovación y transferencia de soluciones de valor, en servicios analíticos, metrológicos, tecnológicos, de gestión y evaluación de la conformidad de a cuerdo a la normativa aplicable", está trabajando en el apoyo a las micro, pequeñas y medianas empresas del país. Como estrategia para contribuir al logro de la misión, se ha iniciado una política de descentralización, eligiendo zonas de actividad con requerimientos similares, en cuanto a las necesidades de mejora de la competitividad de las empresas. En la zona de Montevideo llamada el Cerro, el gobierno municipal gestiona un Parque Tecnológico Industrial, PTIC, apoyando y alojando en su predio, 58 empresas. Este Parque se puede ver como un conglomerado de empresas, en una misma zona, con necesidades similares. El mecanismo de inserción del LATU en el PTIC, ha contado con una herramienta fundamental que es la instalación de una oficina en el propio Parque, cuyo objetivo principal es facilitar y asegurar la contribución del LATU al desarrollo y competitividad de las mipymes allí agrupadas.AbstractAttending to the Technological Laboratory of Uruguay (LATU's mission, to promote the sustainable development of the country and its international insertion through innovation and transfer of valuable solutions, it is working on support for micro, small and medium companies. As a management strategy to achieve the mission, a policy of decentralization, approaching to the enterprises, it's being implemented. In this context, it has been developed a methodology for insertion in the Industrial Technological Park of Cerro, PTIC. This park, which is managed by the municipal government, agglomerates a group of companies, in the same area with similar needs. The LATU's mechanism of insertion in the PTIC, has counted on with a

  1. Characterization of post-fire surface cover, soils, and burn severity at the Cerro Grande Fire, New Mexico, using hyperspectral and multispectral remote sensing

    Science.gov (United States)

    Kokaly, R.F.; Rockwell, B.W.; Haire, S.L.; King, T.V.V.

    2007-01-01

    Forest fires leave behind a changed ecosystem with a patchwork of surface cover that includes ash, charred organic matter, soils and soil minerals, and dead, damaged, and living vegetation. The distributions of these materials affect post-fire processes of erosion, nutrient cycling, and vegetation regrowth. We analyzed high spatial resolution (2.4??m pixel size) Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data collected over the Cerro Grande fire, to map post-fire surface cover into 10 classes, including ash, soil minerals, scorched conifer trees, and green vegetation. The Cerro Grande fire occurred near Los Alamos, New Mexico, in May 2000. The AVIRIS data were collected September 3, 2000. The surface cover map revealed complex patterns of ash, iron oxide minerals, and clay minerals in areas of complete combustion. Scorched conifer trees, which retained dry needles heated by the fire but not fully combusted by the flames, were found to cover much of the post-fire landscape. These scorched trees were found in narrow zones at the edges of completely burned areas. A surface cover map was also made using Landsat Enhanced Thematic Mapper plus (ETM+) data, collected September 5, 2000, and a maximum likelihood, supervised classification. When compared to AVIRIS, the Landsat classification grossly overestimated cover by dry conifer and ash classes and severely underestimated soil and green vegetation cover. In a comparison of AVIRIS surface cover to the Burned Area Emergency Rehabilitation (BAER) map of burn severity, the BAER high burn severity areas did not capture the variable patterns of post-fire surface cover by ash, soil, and scorched conifer trees seen in the AVIRIS map. The BAER map, derived from air photos, also did not capture the distribution of scorched trees that were observed in the AVIRIS map. Similarly, the moderate severity class of Landsat-derived burn severity maps generated from the differenced Normalized Burn Ratio (dNBR) calculation

  2. Fate of Organic Micropollutants during Hydrothermal Carbonization

    Science.gov (United States)

    Weiner, B.; Baskyr, I.; Pörschmann, J.; Kopinke, F.-D.

    2012-04-01

    The hydrothermal carbonization (HTC) is an exothermic process, in which biomass in an aqueous suspension is transformed into a bituminous coal-like material (hydrochar) at temperatures between 180-250°C and under moderate pressure. With these process conditions, little gas is generated (1-5%), and a fraction of the organic carbon is dissolved in the aqueous phase (10-30%) but the largest part is obtained as solid char. The respective yields and the molecular composition depend on the choice of educts and the process conditions, such as temperature, pH-value, and reaction time. Various biomass-educts have recently been studied, such as waste materials from agriculture, brewer's spent grains, sewage sludge, as well as wood and paper materials. Besides their use for energy generation, the hydrochars have also been investigated as soil amendments. Prior to addition of the chars to soil, these should be free of toxic components that could be released into the environment as harmful organic pollutants. Herein, the potential for the degradation of trace organic pollutants, such as pesticides and pharmaceuticals, under typical HTC conditions will be presented. The degradation of selected organic pollutants with different polarity and hydrophobicity was investigated. Scope and limitations of the degradation potential of the HTC are discussed on examples of micro pollutants such as hormones, residues of pharmaceuticals and personal care products including their metabolites, and pesticides. We will show that the target analytes are partially and in some cases completely degraded. The degree of degradation depends on the HTC process conditions such as reaction temperature and time, the solution pH value, the presence of catalysts or additional reagents. The biotic and abiotic degradation of chlorinated organic compounds, in particular chlorinated aromatics, has been a well-known environmental problem and remains a challenging issue for the development of a HTC process for

  3. An improved hydrothermal diamond anvil cell

    Science.gov (United States)

    Li, Jiankang; Bassett, W. A.; Chou, I.-Ming; Ding, Xin; Li, Shenghu; Wang, Xinyan

    2016-05-01

    A new type of HDAC-V hydrothermal diamond anvil cell (HDAC-VT) has been designed to meet the demands of X-ray research including X-Ray Fluorescence, X-ray Absorption Spectroscopy, and small angle X-ray scattering. The earlier version of HDAC-V that offered a large rectangular solid angle used two posts and two driver screws on both sides of a rectangular body. The new version HDAC-VT in a triangular shape has two alternative guide systems, either three posts inserted into bushings suitable for small anvil faces or linear ball bearings suitable for large anvil faces. The HDAC-VT having three driver screws offers the advantage of greater control and stability even though it sacrifices some of the size of solid angle. The greater control allows better sealing of samples, while greater stability results in longer survival for anvils and ceramic parts. This improved design retains several beneficial features of the original HDAC-V as well. These include the small collar that surrounds the heater and sample chamber forming an Ar + H2 gas chamber to protect diamonds and their heating parts from being oxidized. Three linear ball bearings, when used, fit to the three posts prevent seizing that can result from deterioration of lubricant at high temperatures. Positioning the posts and bearings outside of the gas chamber as in HDAC-V also prevents seizing and possible deformation due to overheating. In order to control the heating rate precisely with computer software, we use Linkam T95 and have replaced the Linkam 1400XY heating stage with the HDAC-VT allowing the HDAC to be heated to 950 °C at a rate from 0.01 °C/min to 50 °C/min. We have used the HDAC-VT and Linkam T95 to observe in situ nucleation and growth of zabuyelite in aqueous fluid and to homogenize melt inclusions in quartz from three porphyry deposits in Shanxi, China.

  4. Numerical Simulations of Europa Hydrothermal Plumes

    Science.gov (United States)

    Goodman, J. C.; Lenferink, E.

    2009-12-01

    The liquid water interiors of Europa and other icy moons of the outer solar system are likely to be driven by geothermal heating from the sea floor, leading to the development of buoyant hydrothermal plumes. These plumes potentially control icy surface geomorphology, and are of interest to astrobiologists. We have performed a series of simulations of these plumes using the MITGCM. We assume in this experiment that Europa's ocean is deep (of order 100 km) and unstratified, and that plume buoyancy is controlled by temperature, not composition. A series of experiments was performed to explore a limited region of parameter space, with ocean depth H ranging from 50 to 100 km deep, source heat flux Q between 1 and 10 GW, and values of the Coriolis parameter f between 30% and 90% of the Europa average value. As predicted by earlier work, the plumes in our simulations form narrow cylindrical chimneys (a few km across) under the influence of the Coriolis effect. These plumes broaden over time until they become baroclinically unstable, breaking up into cone-shaped eddies when they become 20-35 km in diameter; the shed eddies are of a similar size. Large-scale currents in the region of the plume range between 1.5 and 5 cm/s; temperature anomalies in the plume far from the seafloor are tiny, varying between 30 and 160 microkelvin. Variations in plume size, shape, speed, and temperature are in excellent agreement with previous laboratory tank experiments, and in rough agreement with theoretical predictions. Plume dynamics and geometry are controlled by a "natural Rossby number" which depends strongly on depth H and Coriolis parameter f, but only weakly on source heat flux Q. However, some specific theoretical predictions are not borne out by these simulations. The time elapsed between startup of the source and the beginning of eddy-shedding is much less variable than predicted; also, the plume temperature varies with ocean depth H when our theory says it should not. Both of

  5. Effect of hydrothermal heat treatment on magnetic properties of copper zinc ferrite rf sputtered films

    OpenAIRE

    Jasmeet Kaur; Thirupathi Gadipelly; Singh, R.

    2016-01-01

    The hydrothermal treatment to the nano-structured films can overcome the destruction of the films. The Cu-Zn Ferrite films were fabricated by RF-sputtering on quartz substrates. Subsequently, the as deposited films were heat treated using hydrothermal process. The X-ray diffraction pattern of the as-deposited and hydrothermal treated films indicate nano-crystalline cubic spinel structure. The amorphous nature of the films is removed after hydrothermal treatment with decreased crystallite size...

  6. Dynamic behavior of Kilauea Volcano and its relation to hydrothermal systems and geothermal energy

    Science.gov (United States)

    Kauhikaua, Jim; Moore, R.B.

    1993-01-01

    Exploitation of hydrothermal systems on active basaltic volcanoes poses some unique questions about the role of volcanism and hydrothermal system evolution. Volcanic activity creates and maintains hydrothermal systems while earthquakes create permeable fractures that, at least temporarily, enhance circulation. Magma and water, possibly hydrothermal water, can interact violently to produce explosive eruptions. Finally, we speculate on whether volcanic behavior can be affected by high rates of heat extraction.

  7. Concerns of Hydrothermal Degradation in CAD/CAM Zirconia

    OpenAIRE

    Kim, J.-W.; Covel, N.S.; Guess, P.C.; Rekow, E.D.; Zhang, Y.

    2010-01-01

    Zirconia-based restorations are widely used in prosthetic dentistry; however, their susceptibility to hydrothermal degradation remains elusive. We hypothesized that CAD/CAM machining and subsequent surface treatments, i.e., grinding and/or grit-blasting, have marked effects on the hydrothermal degradation behavior of Y-TZP. CAD/CAM-machined Y-TZP plates (0.5 mm thick), both with and without subsequent grinding with various grit sizes or grit-blasting with airborne alumina particles, were subj...

  8. Implementation of model predictive control on a hydrothermal oxidation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Muske, K.R. [Villanova Univ., PA (United States). Dept. of Chemical Engineering; Dell`Orco, P.C.; Le, L.A.; Flesner, R.L. [Los Alamos National Lab., NM (United States). High Explosives Science and Technology Group

    1998-12-31

    This paper describes the model-based control algorithm developed for a hydrothermal oxidation reactor at the Pantex Department of Energy facility in Amarillo, Texas. The combination of base hydrolysis and hydrothermal oxidation is used for the disposal of PBX 9404 high explosive at Pantex. The reactor oxidizes the organic compounds in the hydrolysate solutions obtained from the base hydrolysis process. The objective of the model predictive controller is to minimize the total aqueous nitrogen compounds in the effluent of the reactor. The controller also maintains a desired excess oxygen concentration in the reactor effluent to ensure the complete destruction of the organic carbon compounds in the hydrolysate.

  9. Hydrothermal liquefaction of microalgae's for bio oil production

    DEFF Research Database (Denmark)

    Toor, Saqib; Reddy, Harvind; Deng, Shuguang;

    process water for algae cultivation. GC-MS, elemental analyzer, calorimeter and nutrient analysis were used to analyze bio-crude, lipid-extracted algae and water samples produced in the hydrothermal liquefaction process. The highest bio-oil yield of 46% was obtained on Nannochloropsis salina at 310 °C...... and 107 bar. For Spirulina platensis algae sample, the highest bio-oil yield is 38% at 350 °C and 195 bar. Preliminary data also indicate that a lipid-extracted algae solid residue sample obtained in the hydrothermal liquefaction process contains a high level of proteins...

  10. Fabrication Of Titania Nanotubes By A Modified Hydrothermal Method

    OpenAIRE

    Meor Yusoff M.S; Masliana M M; Wilfred Paulus; Parimala Devi; Mahdi E. Mahmoud

    2011-01-01

    The main setback of the fabrication of titania nanotubes by the hydrothermal method is the long dissolution time and the usage of highly concentrated NaOH. Our group has managed to develop a modified hydrothermal process that is capable of fabricating titania nanotubes in a shorter timespan while using a more dilute NaOH solution. The study shows that the titania nanotubes starts to form from 7 hours of dissolution, and more nanotubes is produced as the dissolution duration is extended. Simil...

  11. Hydrothermal systems on Mars: an assessment of present evidence.

    Science.gov (United States)

    Farmer, J D

    1996-01-01

    Hydrothermal processes have been suggested to explain a number of observations for Mars, including D/H ratios of water extracted from Martian meteorites, as a means for removing CO2 from the Martian atmosphere and sequestering it in the crust as carbonates, and as a possible origin for iron oxide-rich spectral units on the floors of some rifted basins (chasmata). There are numerous examples of Martian channels formed by discharges of subsurface water near potential magmatic heat sources, and hydrothermal processes have also been proposed as a mechanism for aquifer recharge needed to sustain long term erosion of sapping channels. The following geological settings have been identified as targets for ancient hydrothermal systems on Mars: channels located along the margins of impact crater melt sheets and on the slopes of ancient volcanoes; chaotic and fretted terranes where shallow subsurface heat sources are thought to have interacted with ground ice; and the floors of calderas and rifted basins (e.g. chasmata). On Earth, such geological environments are often a locus for hydrothermal mineralization. But we presently lack the mineralogical information needed for a definitive evaluation of hypotheses. A preferred tool for identifying minerals by remote sensing methods on Earth is high spatial resolution, hyperspectral, near-infrared spectroscopy, a technique that has been extensively developed by mineral explorationists. Future efforts to explore Mars for ancient hydrothermal systems would benefit from the application of methods developed by the mining industry to look for similar deposits on Earth. But Earth-based exploration models must be adapted to account for the large differences in the climatic and geological history of Mars. For example, it is likely that the early surface environment of Mars was cool, perhaps consistently below freezing, with the shallow portions of hydrothermal systems being dominated by magma-cryosphere interactions. Given the smaller

  12. Geothermal energy - hydrothermal utilisation of geothermal energy in Germany

    International Nuclear Information System (INIS)

    In this phase of developing and utilisation of geothermal potentials the hydrothermal sector plays a very important role due to its possibilities of supplying heat in the MW-range at any time of day or night or year. The heat is contained in thermal water extracted from depth between 2000 and 2500 m by means of deep drilling. In Germany there are hydrothermal potentials in the South (Rhine Valley) and North. The following article describes the geological, technological and economic aspects of thermal water utilisation for the generation of thermal energy. (orig.)

  13. Global Fluorine Flux Associated with Submarine Hydrothermal Fluids

    Science.gov (United States)

    Kagoshima, T.; Sano, Y.

    2015-12-01

    We estimated a fluorine flux associated with hydrothermal fluid emission at mid-ocean ridges (MOR) based on vent fluid chemistry and MORB vesicle compositions. Multiplication of fluorine concentrations in submarine hydrothermal fluids and the vent fluid flux at MOR may give us an estimate of fluorine flux at MOR. A worldwide vent chemistry research [1] suggested that submarine vent fluids are depleted in fluorine (Elsevier, London). [2] Coogan & Dosso (2012) EPSL 323-324, 92-101. [3] Kagoshima et al. (2014) Japan Geoscience Union Meeting 2014 Abstract #SGC56-P01. [4] Fischer (2008) Geochem. J. 42, 21-38.

  14. The characteristics of hydrothermal plumes observed in the Precious Stone Mountain hydrothermal field, the Galapagos spreading center

    Science.gov (United States)

    Chen, S.; Tao, C.; Li, H.; Zhou, J.; Deng, X.; Tao, W.; Zhang, G.; Liu, W.; He, Y.

    2014-12-01

    The Precious Stone Mountain hydrothermal field (PSMHF) is located on the southern rim of the Galapagos Microplate. It was found at the 3rd leg of the 2009 Chinese DY115-21 expedition on board R/V Dayangyihao. It is efficient to learn the distribution of hydrothermal plumes and locate the hydrothermal vents by detecting the anomalies of turbidity and temperature. Detecting seawater turbidity by MAPR based on deep-tow technology is established and improved during our cruises. We collected data recorded by MAPR and information from geological sampling, yielding the following results: (1)Strong hydrothermal turbidity and temperature anomalies were recorded at 1.23°N, southeast and northwest of PSMHF. According to the CTD data on the mooring system, significant temperature anomalies were observed over PSMHF at the depth of 1,470 m, with anomalies range from 0.2℃ to 0.4℃, which gave another evidence of the existence of hydrothermal plume. (2)At 1.23°N (101.4802°W/1.2305°N), the nose-shaped particle plume was concentrated at a depth interval of 1,400-1,600 m, with 200 m thickness and an east-west diffusion range of 500 m. The maximum turbidity anomaly (0.045 △NTU) was recorded at the depth of 1,500 m, while the background anomaly was about 0.01△NTU. A distinct temperature anomaly was also detected at the seafloor near 1.23°N. Deep-tow camera showed the area was piled up by hydrothermal sulfide sediments. (3) In the southeast (101.49°W/1.21°N), the thickness of hydrothermal plume was 300 m and it was spreading laterally at a depth of 1,500-1,800 m, for a distance about 800 m. The maximum turbidity anomaly of nose-shaped plume is about 0.04 △NTU at the depth of 1,600 m. Distinct temperature anomaly was also detected in the northwest (101.515°W/1.235°N). (4) Terrain and bottom current were the main factors controlling the distribution of hydrothermal plume. Different from the distribution of hydrothermal plumes on the mid-ocean ridges, which was mostly

  15. Living with the Heat. Submarine Ring of Fire--Grades 5-6. Hydrothermal Vent Ecology.

    Science.gov (United States)

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity is designed to teach about hydrothermal vent ecology. Students are expected to describe how hydrothermal vents are formed and characterize the physical conditions at these sites, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in hydrothermal vent…

  16. Andesita Cerro Bola: Nueva unidad vinculada al magmatismo mioceno de la Cordillera de Olivares, San Juan, Argentina (30°35´S; 69°30´O Cerro Bola Andesite: New unit linked to the Miocene magmatism of the Olivares Cordillera, San Juan (30°35' S ; 68°30' W

    Directory of Open Access Journals (Sweden)

    A.F. Wetten

    2005-03-01

    Full Text Available El área de estudio se halla en la zona de Tocota, inmediatamente al este de la Cordillera de Olivares, en el borde oriental de la Cordillera Frontal, provincia de San Juan. En ella se encuentran unidades ígneas y sedimentarias del ciclo gondwánico, las que fueron intruidas y cubiertas en relación discordante por cuerpos subvolcánicos y volcánicos asignados anteriormente al ciclo ándico en sentido amplio, los cuales constituyen el principal objeto del presente estudio. Estos cuerpos han sido mapeados a fin de poder caracterizarlos adecuadamente, en el contexto estratigráfico de la región. Los afloramientos de interés han sido reconocidos en el cerro Bola y alrededores, donde se observan distribuidos irregularmente, cubriendo un área superior a 5 km². Las rocas, de coloración gris clara y composición andesítica - fenoandesítica, presentan estructuras de domo y colada. Estos afloramientos serían correlacionables con la unidad volcánica Pircas (Mioceno, la que aflora al oeste, y conformarían un evento magmático posterior al de pórfidos de diferente composición situados tanto en el arroyo Chita como en el cerro Divisadero. La extensión del área involucrada, la uniformidad litológica, el bajo grado de alteración y una edad radimétrica obtenida por el método K/Ar, fueron considerados para proponer a estas volcanitas como una unidad litoestratigráfica de edad miocena superior, con la denominación de Andesita Cerro Bola.The study area is located in the region of Tocota Creek, close to the Cordillera Olivares, eastern border of the Frontal Range, San Juan province. In this place, igneous and sedimentary units belonging to the Gondwanic cycle, were recognized. These units were intruded and unconformably covered by subvolcanic and volcanic bodies, which were commonly referred to the Tertiary or Andean cycle. The study of these bodies is the main proposal of this work. These bodies had been mapped in order to characterize them

  17. Edad y rasgos petrográficos y geoquímicos de cuerpos subvolcánicos asignables a la Formación Cerro León, este del Macizo del Deseado, Santa Cruz Age and petrography and geochemistry features of subvolcanic outcrops from Cerro León Formation, east of the Deseado Massif, Santa Cruz

    Directory of Open Access Journals (Sweden)

    D. Guido

    2004-12-01

    Full Text Available Se presentan nuevos afloramientos de cuerpos subvolcánicos correlacionables con la Formación Cerro León en el sector oriental del Macizo del Deseado. Esta unidad aflora en dos sectores, en el bajo Leonardo y en el afloramiento Bahía Laura del Complejo Río Deseado. El primer sector presenta trece diques y un filón capa intruyendo a las sedimentitas pérmicas de la Formación La Golondrina y el segundo sector comprende tres diques que intruyen a rocas del basamento. Se trata de rocas de color gris a negro, frecuentemente alteradas, con textura microgranuda a porfírica, con fenocristales de plagioclasa, diópsido (En42 Fs11 Wo47 y en menor medida de hornblendas ricas en Mg (magnesio hastingsita, en una matriz holocristalina de textura intergranular. Son rocas subalcalinas de composiciones basalto-andesita y con afinidades calcoalcalinas. La edad Ar/Ar obtenida en una de estas muestras (180,1±1,5 Ma representa la primer determinación realizada en esta unidad y es coherente con las relaciones estratigráficas observadas para esta formación. La comparación con rocas ígneas jurásicas de la provincia geológica Macizo del Deseado, favorece la vinculación temporal y genética con el evento volcánico-piroclástico del Jurásico medio a superior (Formación Bajo Pobre y Grupo Bahía Laura. Sin embargo, la diferencia en las edades Ar/Ar, sugieren una interrupción entre el evento subvolcánico (180 Ma y el volcanismo Jurásico medio a superior (177 a 150 Ma. Se considera, preliminarmente, que los cuerpos subvolcánicos de la Formación Cerro León representarían las primeras evidencias magmáticas del rift jurásico en el Macizo del Deseado.New subvolcanic outcrops, correlated with the Cerro León Formation and located in the eastern Deseado Massif, are presented. This unit outcrops in two sectors, the Leonardo depression and the Bahía Laura outcrop of the Río Deseado Complex. In the first sector there are thirteen dikes and a sill

  18. Evolución magmática del Granito Peñón Rosado, Cerro Asperecito, flanco occidental de la sierra de Famatina Magmatic evolution of the Peñón Rosado Granite, Cerro Asperecito, western flank of the Famatina range

    Directory of Open Access Journals (Sweden)

    J.A. Dahlquist

    2006-03-01

    Full Text Available El granate es un mineral accesorio poco común en rocas ígneas y constituye un tema relevante de la petrología ígnea. Estudios combinados de petrología, química mineral, geoquímica de roca total y geoquímica isotópica en el cerro Asperecito indican que los granitoides con granate que forman el Granito Peñón Rosado (GPR fueron producidos por la fusión parcial de rocas metasedimentarias con subsecuente diferenciación durante su emplazamiento en el Ordovícico inferior-medio. En este sentido, la facies GPR1 representa un cristalizado temprano, la facies GPR2 representa un fundido diferenciado, y la facies GPR3 un fundido residual. El Granito Peñón Rosado, fue emplazado en condiciones de moderada temperatura (785ºC y presión media (4,4 kb en profundidades de la corteza media (~15 km. El emplazamiento casi sincrónico en la corteza media de una abundante suite metaluminosa durante el Ordovícico inferior-medio (468 Ma en el cerro Asperecito fue suficiente para inducir anatexis local de los metasedimentos circundantes. Los contenidos de elementos mayoritarios (CaO, Na2O y elementos traza (Rb, Sr, Ba en el Granito Peñón Rosado sugieren anatexis a partir de un material inmaduro acumulado en un plataforma continental. Así, el Granito Peñón Rosado es un típico granitoide tipo-S con granate y el modelo establecido aquí puede contribuir a un mejor entendimiento acerca de la cristalización del granate en rocas graníticas.Garnet is an uncommon accessory mineral in igneous rocks and is a relevant petrologic topic. Combined petrology, chemistry/mineralogy, whole-rock geochemistry, and isotopic geochemistry studies in the cerro Asperecito indicate that the garnet-bearing granitoids of the Peñón Rosado Granite (PRG were produced by partial melting of metasedimentary rocks and subsequent differentiation during their emplacement at the Early-Middle Ordovician. In this way the PRG1 facies represent an early crystallized, the PRG2 facies

  19. El volcanismo bimodal del volcán cerro Corona, Alta Sierra de Somún Curá, provincia de Río Negro Bimodal volcanism of the Cerro Corona volcano in the Alta Sierra de Somún Curá (Río Negro province

    Directory of Open Access Journals (Sweden)

    Guadalupe Maro

    2012-03-01

    Full Text Available La Alta Sierra de Somún Curá es uno de los complejos volcánicos terciarios postplateau en el ambiente de la meseta basáltica de Somún Curá, en la Patagonia extrandina. En ella se encuentra el cerro Corona, un volcán en escudo que corresponde al centro de mayor altura en la región. Está construido por rocas efusivas y piroclásticas subordinadas, fundamentalmente traquiandesíticas-basálticas, con variaciones traquíticas tanto en sus flancos como en su cráter. A pesar de la bimodalidad compositional con una importante discontinuidad entre el 54 y 58 % en peso de SiO2, el presente trabajo propone que las traquitas son el producto de la evolución por cristalización fraccionada de las traquiandesitas basálticas, con cierta influencia de recargas máficas a la cámara magmática de acuerdo a la presencia de texturas de desequilibrio en los fenocristales, principalmente de las rocas félsicas.The Cerro Corona is a shield volcano situated in the Alta Sierra de Somún Curá, one of the tertiary volcanic complex that constitute the Meseta de Somún Curá, in the Extrandean Patagonia. It is the highest center in the region and it is compound mainly of basaltic trachyandesites, with trachytic variations on its flanks and crater. Despite the compositional bimodality with an important compositional gap between 54% and 58% in weight in SiO2, this work suggests that trachytes are the product of the evolution of basaltic trachyandesites through fractional crystallization, with some influence of mafic recharge to the magmatic chamber, in agreement with the presence of disequilibrium textures in fenocrystals, essentially in felsic rocks.

  20. ANÁLISIS DE MACRORRESTOS VEGETALES EN EL SITIO ARQUEOLÓGICO LOS TRES CERROS 1 (ISLA LAS MORAS, VICTORIA, ENTRE RÍOS / Macroremains plant analysis on the Tres Cerros 1 archaeological site (Las Moras island, Victoria, Entre Ríos.

    Directory of Open Access Journals (Sweden)

    María de los Milagros Colobig

    2015-06-01

    Full Text Available El presente trabajo es la primera aproximación al estudio de macrorrestos botánicos en el sitio Los Tres Cerros 1 (isla Las Moras, Victoria, Entre Ríos. Estos restos fueron recuperados mediante la técnica de flotación manual. A partir del material extraído, se exploró el rol de los recursos vegetales y su importancia en la subsistencia en los grupos humanos que habitaron el Delta Superior del río Paraná durante el Holoceno tardío. Se identificaron cinco familias: Solanaceae, Chenopodiaceae, Polygonaceae, Poaceae (Maideae y Oryzoideae y Amaranthaceae. Los estudios permitieron estimar que a partir de 700 ARCP hubo un incremento en la abundancia y variabilidad de recursos vegetales utilizados con respecto a períodos anteriores. La presencia de elementos oryzoides, y graminoides (específicamente Maideae evidenció la existencia de vegetales silvestres y domesticados, aportando nuevos registros sobre el aprovechamiento, manejo y cultivo de las plantas en el área de estudio en el Holoceno tardío.   Abstract  This paper entails the first approach to macrobotanical remains obtained from Los Tres Cerros 1 (Isla Las Moras, Victoria, Entre Ríos. The remains were recovered by means of manual flotation technique. The extracted material allowed us to explore the role played by vegetable resources role and their importance to the subsistence of human populations of Upper Paraná Delta during the late Holocene. Five botanical families were recognized: Solanaceae, Chenopodiaceae, Polygonaceae, Poaceae (Maideae and Ehrhartoideae and Amaranthaceae. Studies estimate that from 700 RCYBP, there was an increase in the abundance and variability of plant resources used, as compared to previous periods. The presence of oryzoides and graminoid elements (specifically Maideae showed the presence of wild and domesticated plants, providing new records on the use of plants in the area studied, in the late Holocene.

  1. Health assessment for Northwestern States Portland Cement Company, Mason City, Cerro Gordo County, Iowa, Region 7. CERCLIS No. IAD980852461. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-27

    The Northwestern States Portland Cement Company (NWSPCC) NPL site is situated in the northern section of Mason City, Cerro Gordo County, Iowa. The major concern at the site is contaminated surface water and ground water as a result of contact with waste cement kiln dust in the West Quarry. On-site surface water and ground water are contaminated with lead, sodium, sulfates, and reflects high pH. The waste kiln dust is in contact with both the surficial and Devonian aquifers on site; hence, there is a potential for contamination of the Devonian aquifer off-site. Potential exposure pathways of concern include ingestion of contaminated ground water; accidental ingestion and dermal contact with contaminated surface water, and accidental ingestion and dermal contact with contaminated soils and sediment; and inhalation of entrained dust. Under current conditions the NWSPCC NPL site poses no apparent public health hazard. However, potential risk to human health resulting from possible exposure to on-site and off-site hazardous substances exists in the future if the site is not remediated. The site is currently under remediation to mitigate the potential risk.

  2. El volcanismo bimodal del volcán cerro Corona, Alta Sierra de Somún Curá, provincia de Río Negro

    Directory of Open Access Journals (Sweden)

    Guadalupe Maro

    2012-03-01

    Full Text Available La Alta Sierra de Somún Curá es uno de los complejos volcánicos terciarios postplateau en el ambiente de la meseta basáltica de Somún Curá, en la Patagonia extrandina. En ella se encuentra el cerro Corona, un volcán en escudo que corresponde al centro de mayor altura en la región. Está construido por rocas efusivas y piroclásticas subordinadas, fundamentalmente traquiandesíticas-basálticas, con variaciones traquíticas tanto en sus flancos como en su cráter. A pesar de la bimodalidad compositional con una importante discontinuidad entre el 54 y 58 % en peso de SiO2, el presente trabajo propone que las traquitas son el producto de la evolución por cristalización fraccionada de las traquiandesitas basálticas, con cierta influencia de recargas máficas a la cámara magmática de acuerdo a la presencia de texturas de desequilibrio en los fenocristales, principalmente de las rocas félsicas.

  3. Medición de gas Radón (RN222 en aguas termales del Cerro Pacho, Caldera Coatepeque, El Salvador

    Directory of Open Access Journals (Sweden)

    Ramiro Rodríguez

    2014-06-01

    Full Text Available Se presentan concentraciones de radón (Rn222 y evaluación de radio (Ra226 disueltos en agua. El objetivo es contribuir al monitoreo volcánico, adaptando y validando metodología analítica. El muestreo fue de tipo discreto y mensual, desde junio 2011 hasta marzo 2013. Las concentraciones de radón varían de 0,48 ± 0,1 a 1,54 ± 0,13 Bq/L (promedio 1,24 Bq/L; concentraciones de radio se evaluaron de enero a diciembre 2012, los valores encontrados no demuestran detección de radio al nivel de confianza del 95 % respecto al límite de detección (4,2 mBq/L. En noviembre 2012 se observó disminución de radón, posiblemente relacionado a anomalías de subducción con epicentro a 143 km del cerro Pacho, registrando sismicidad volcánica 40 días antes con incrementos de microsismos y actividad volcano-tectónica. Se ha generado las primeras mediciones de radón en agua termal, estableciendo la línea base para evaluar el comportamiento de estos radionucleidos con la actividad sísmica.

  4. Charnockitic ortho gneisses and mafic granulite s of the Cerro Olivo complex, south-east Uruguay, Part 2: lithogeochemistry, mineral o chemistry and thermo barometry

    International Nuclear Information System (INIS)

    The Cerro Olivo complex in SE-Uruguay shows different kinds of orthogneisses containing biotite, amphibole and/or orthopyroxene-biotite (charnockitic gneisses). Minor occurrences of mafic granulites are associated. They include low and high pressure kinds. We present the lithogeochemistry and compared mineral chemistry analyses of both the charnockitic orthogneisses and the mafic rocks. Theres i a calc-alkaline geochemical affinity of the biotite-bearing and charnockitic gneisses, while the mafic rocks could derive from tholeitic gabbros. These results allow discrininatieg two kinds of mafic rocks: Low and hight MgO contents, both representing respectively garnet-bearing and garnet-free mafic granulites. The orthopyroxene in the Opx-Bt orthogneisses in FE-rich while MgO-rich mafic rocks show hypersthenes. The thermobarometric data of mafic granulites show temperatures higher than 850°C and two contrasting mineral assemblages, one formed by ∼ 1 Kbar and 770° - 800°C (pre-M). and the other by 5.5 Kbar and 680-700° (M). The mineral chemistry suggests the occurrence of contrasting protoliths to explain the stability of two different mineral associations

  5. NUEVOS APORTES AL CONOCIMIENTO DE LA HERPETOFAUNA DE LA FORMACIÓN CERRO AZUL (MIOCENO SUPERIOR, PROVINCIA DE LA PAMPA, ARGENTINA

    Directory of Open Access Journals (Sweden)

    AGUSTÍN SCANFERLA

    2015-01-01

    Full Text Available RESUMENSe describen nuevos materiales fósiles de anfibios y reptiles hallados en sedimentos referidos a la Formación Cerro Azul (Mioceno Superior, procedentes de numerosas localidades de la provincia de La Pampa, Argentina. Los nuevos registros se basan en un resto craneano de anuro asignado al géneroCeratophrys, restos de caparazón de tortugas terrestres del géneroChelonoidis, vértebras asignables al lagarto de la familia TeiidaeTupinambis, y una vértebra troncal de serpiente comparable al género de colubroideos actualesPhilodryas. Tanto los registros terciarios previos de géneros actuales de anfibios y reptiles en América del Sur, como así también la asociación recuperada en el Mioceno Superior de La Pampa sugieren que la mayoría de los géneros que componen la herpetofauna Neotropical estaban presentes en el Mioceno, patrón similar al observado en otras regiones del mundo.

  6. Jurassic tetrapods and flora of Cañadón Asfalto Formation in Cerro Cóndor area, Chubut Province

    Directory of Open Access Journals (Sweden)

    Ignacio H. Escapa

    2008-12-01

    Full Text Available The plant and tetrapod fossil record of the Cañadón Asfalto Formation (Middle to Late Jurassic found in Cerro Cóndor area (Chubut Province is summarized here. The flora is dominated by conifers (Araucariaceae, Cupressaceae sensu lato but also includes ferns and equisetaleans. The tetrapod fauna is composed of dinosaur taxa described in the 70's as well as other remains recently described and other vertebrate groups such as amphibians, turtles, and mammals. The amphibian remains have been interpreted as representatives of a new species of Notobatrachus, considered one of the most basal members of the anuran lineage. Similarly, turtle remains have been recently recognized as a new species of basal turtle, bringing valuable information about the early evolution of this group. The dinosaur remains are largely dominated by saurischian taxa, represented by basal forms of Eusauropoda and Tetanurae. In addition, three different mammalian species have been identified and considered as early representatives of an endemic Gondwanan mammalian fauna. The fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.

  7. Sulfur isotopic composition of modern seafloor hydrothermal sediment and its geological significance

    Institute of Scientific and Technical Information of China (English)

    曾志刚; 李军; 蒋富清; 秦蕴珊; 翟世奎

    2002-01-01

    A total of 1 264 sulfur isotopic values for modem seafloor hydrothermel sediments from different hydrothermal fidds have been collected. On this basis, combining our sulfur isotpic data for surface hydrothermal sediments from the Jade hydrohtermal field in the Okinawa Trough and the TAG hydrothermal field in the Mid-Atlantic Ridge, respectively, and comparing the sulfur isotopic compositions and analyzing their sources of sulfur in seafloor hydrothermal sediments from different geologic-tectonic setting, the results show that: ( 1 ) sulfur isotopic values of sulfides and sulfates in modern seafloor hydrothermal sediments are concentrated in a narrow range, δ34S values of sulfides vary from l × 10-3 to 9 × 10- 3, with a mean of 4.5 × 10- 3 ( n = 1 042), δ34S values of sulfates vary from 19 × 10- 3 to 24× 10-3, with a mean of 21.3× 10-3 (n =217); (2) comparing the sulfur isotopic compositions of hydrothermal sediments from the sediment-hosted hydrothermal fields, the range of sulfur isotopic values for hydrothermal sediments from the sediment-free hydrothermal fields is narrow relatively; (3) the differences of sulfur isotopic compositions in sulfides from different hydrothermal fields show the differences in the sources of sulfur. The sulfur of hydrothermal sulfides in the sediment-free mid-ocean ridges is mainly from mid-ocean ridge basalt, and partially from the reduced seawater sulfate, and it is the result of partially reduced seawater sulfate mixed with basaltic sulfur. In the sediment-hosted nid-ocean ridges and the back-arc basins, the volcanics, the sediments and the organic matters also can offer their sulfur for forming hydrothermal sulfides; (4) the variations of sulfur isotopic compositions and the different sources of sulfur for hydrothermal sediments may be attributed to the various physical-chemical characteristics of hydrothermal fluids, the magmatic evolution and the different geologic-tectonic settings of seafloor hydrothermal systems.

  8. Hydrothermal synthesis, characterization, and magneticproperties of cobalt chromite nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Zákutná, Dominika; Repko, A.; Matulková, I.; Nižňanský, Daniel; Ardu, A.; Cannas, C.; Mantlíková, Alice; Vejpravová, Jana

    2014-01-01

    Roč. 16, č. 2 (2014), 1-14. ISSN 1388-0764 R&D Projects: GA ČR GAP108/10/1250 Institutional support: RVO:68378271 ; RVO:61388980 Keywords : cobalt chromite * hydrothermal method * nanoparticles * size effect * multiferroic materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.184, year: 2014

  9. Nitrogen-containing hydrothermal carbons with superior performance in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Li [Colloid Chemistry Department, Max-Planck Institute for Colloids and Interfaces, Am Muehlenberg 1, 14424 Potsdam (Germany); Institute of Coal Chemistry, Chinese Academy of Sciences, 27th Taoyuan South Road, 030001 Taiyuan (China); Fan, Li-Zhen; Zhou, Meng-Qi; Guan, Hui; Qiao, Suyan [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Antonietti, Markus; Titirici, Maria-Magdalena [Colloid Chemistry Department, Max-Planck Institute for Colloids and Interfaces, Am Muehlenberg 1, 14424 Potsdam (Germany)

    2010-12-01

    Microporous nitrogen-doped carbons produced by hydrothermal carbonization of biomass derivative followed by chemical activation showed excellent supercapacitive capacitance performance both in acid and base electrolytes. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Borehole plugging by hydrothermal transport. A feasibility report

    International Nuclear Information System (INIS)

    The possibility of forming borehole plugs by hydrothermal transport was examined with respect to five systems, utilizing available literature data. In general, it would appear possible to create plugs with hydrothermal cements, with hydrothermally transported quartz, and with carbonates precipitated in-situ using carbon dioxide or carbon dioxide and water as reacting fluids. Hydrothermal cements appear to be most feasible from an engineering and economic point of view using a slurry with a lime-alumina-silica composition carried into the hole in a single pipe at temperatures in the range of 2000C and requiring only enough pressure to drive the mixture into the hole. Quartz or chalcedony plugs would be the most impervious, have the lowest chemical reactivity with groundwater, the lowest thermal expansion, and be most compatible with the wall rock. Deposition is likely to be slow, and there are severe engineering problems associated with a single pipe system carrying silica-rich solutions at temperatures in excess of 5000C at pressure of 2000 bars (30,000 psi). Calcite plugs could be formed as compatible plug materials in contact with a limestone or dolomite wall rock. It is not known whether non-porous plugs can be readily formed and there is also a problem of chemical reaction with percolating groundwater. The clay-water and sulfur-water systems do not appear to be viable plug systems. In-situ reconstitution of the wall rock does not appear to be an economically feasible possibility

  11. HYDROTHERMAL REACTIONS OF CORROSION PRODUCTS IN REACTOR PRIMARY CONDITIONS

    Czech Academy of Sciences Publication Activity Database

    Zmítko, M.; Grygar, Tomáš; Štengl, Václav; Šubrt, Jan; Kláriková, Adriana

    Kashiwazaki : JAIF, 1998, s. 707-714 [1998 JAIF International Conference on Water Chemistry in Nuclear Power Plants. Kashiwazaki (JP), 13.10.1998-16.10.1998] Institutional research plan: CEZ:AV0Z4032918 Keywords : VVER reactors * iron oxides * hydrothermal reactions Subject RIV: CA - Inorganic Chemistry

  12. A hydrothermal seedling emergence model for giant ragweed (Ambrosia trifida)

    Science.gov (United States)

    Late-season seedling emergence of giant ragweed in Ohio crop fields complicates efforts for predicting the optimum time to implement control measures for minimizing crop-yield losses. Our objectives were to develop a hydrothermal seedling emergence model for a late-emerging biotype in Ohio and valid...

  13. PROCESS IMPROVEMENT STUDIES ON THE BATTELLE HYDROTHERMAL COAL PROCESS

    Science.gov (United States)

    The report gives results of a study to improve the economic viability of the Battelle Hydrothermal (HT) Coal Process by reducing the costs associated with liquid/solid separation and leachant regeneration. Laboratory experiments were conducted to evaluate process improvements for...

  14. Optimizing hydrothermal pretreatment of sugarcane bagasse using response surface methodology

    Science.gov (United States)

    Sugarcane bagasse was characterized as a feedstock for production of ethanol using hydrothermal pretreatment. Reaction temperature and time were varied between 160-200 deg C and 5-20 min, respectively, using a response surface experimental design. The liquid fraction was analyzed for soluble carbohy...

  15. The significance of water phase transition in the hydrothermal mineralization

    International Nuclear Information System (INIS)

    Water is the main composition of the geo-fluid in the hydrothermal mineralization. The phase transition of water is also the key factor to understand the processes of hydrothermal mineralization, as well as the reactions among various substances and the geological evolutions. The paper, takes the iso-pressure heat capacity (Cp) for example of physicochemical properties, has studies the changing regularity of Cp according to temperature and pressure in the crust with the method from National Institute of Standards and Technology (NIST) and showed that the phase transition of water can cause the sharp variations of the physicochemical properties of water and is one of the essential factors to hydrothermal mineralization. From the study the paper has also revealed the interior coupling relations between the phase transitions of water and fracture or magma activities. Furthermore, the article suggests that the corresponding relations between fracture epoch and metallogenic epoch can be created by the aid of the water phase transitions and concludes the phase transition of water is the important factor to control the hydrothermal mineralization. (authors)

  16. Subcritical hydrothermal conversion of organic wastes and biomass. Reaction pathways

    Directory of Open Access Journals (Sweden)

    Alejandro Amadeus Castro Vega

    2010-04-01

    Full Text Available Hydrothermal conversion is a procedure which emulates organic matter’s natural conversion into bio-crude having physical and chemical properties analogous to petroleum. The artificial transformation of biomass requi- res previous knowledge of the main reaction routes and product availability. The main component of biomass (depolymerisation by hydrolysis is presented in hydrothermal cellulose conversion, producing oligosaccharides which exhibit dehydration and retro-aldol condensation reactions for transforming into furfurals and carboxylic acids. Other biomass components (such as lignin, proteins, and fat esters present both hydrolysis and pyrolysis reaction routes. As long as biomass mainly contains carbohydrates, subcritical hydrothermal conversion products and their wastes will be fundamentally analogous to those displaying cellulose. These substances have added- value by far surpassing raw material’s acquisition cost. When the main hydrothermal conversion products’ O/C, H/C molar ratios as reported in literature are plotted, an evolutionary tralectory for conversion products appears to be closely or even overlapped with fossil fuels’ geological evolution.

  17. Hydrothermal decomposition of liquid crystal in subcritical water

    International Nuclear Information System (INIS)

    Highlights: • Hydrothermal technology can effectively decompose the liquid crystal of 4-octoxy-4'-cyanobiphenyl. • The decomposition rate reached 97.6% under the optimized condition. • Octoxy-4'-cyanobiphenyl was mainly decomposed into simple and innocuous products. • The mechanism analysis reveals the decomposition reaction process. - Abstract: Treatment of liquid crystal has important significance for the environment protection and human health. This study proposed a hydrothermal process to decompose the liquid crystal of 4-octoxy-4′-cyanobiphenyl. Experiments were conducted with a 5.7 mL stainless tube reactor and heated by a salt-bath. Factors affecting the decomposition rate of 4-octoxy-4′-cyanobiphenyl were evaluated with HPLC. The decomposed liquid products were characterized by GC-MS. Under optimized conditions i.e., 0.2 mL H2O2 supply, pH value 6, temperature 275 °C and reaction time 5 min, 97.6% of 4-octoxy-4′-cyanobiphenyl was decomposed into simple and environment-friendly products. Based on the mechanism analysis and products characterization, a possible hydrothermal decomposition pathway was proposed. The results indicate that hydrothermal technology is a promising choice for liquid crystal treatment

  18. Hydrothermal synthesis for high-quality CdTe nanocrystals

    International Nuclear Information System (INIS)

    Synthesis of water-soluble CdTe nanocrystals with high photoluminescence quantum yield and narrow fluorescence emission spectra is developed under the conditions of low precursor concentration and moderate temperature of hydrothermal growth. The relatively high temperature accelerates the particle growth rate and enhances the photoluminescence quantum yield. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Ethanol Production from Hydrothermally-Treated Biomass from West Africa

    DEFF Research Database (Denmark)

    Bensah, Edem C.; Kádár, Zsófia; Mensah, Moses Y.

    2015-01-01

    Despite the abundance of diverse biomass resources in Africa, they have received little research and development focus. This study presents compositional analysis, sugar, and ethanol yields of hydrothermal pretreated (195 degrees C, 10 min) biomass from West Africa, including bamboo wood, rubber ...

  20. Hydrothermal decomposition of liquid crystal in subcritical water

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Xuning [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Shanghai Cooperative Centre for WEEE Recycling, Shanghai Second Polytechnic University, No. 2360 Jinhai Road, Shanghai 201209 (China); He, Wenzhi, E-mail: hithwz@163.com [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Li, Guangming; Huang, Juwen; Lu, Shangming; Hou, Lianjiao [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China)

    2014-04-01

    Highlights: • Hydrothermal technology can effectively decompose the liquid crystal of 4-octoxy-4'-cyanobiphenyl. • The decomposition rate reached 97.6% under the optimized condition. • Octoxy-4'-cyanobiphenyl was mainly decomposed into simple and innocuous products. • The mechanism analysis reveals the decomposition reaction process. - Abstract: Treatment of liquid crystal has important significance for the environment protection and human health. This study proposed a hydrothermal process to decompose the liquid crystal of 4-octoxy-4′-cyanobiphenyl. Experiments were conducted with a 5.7 mL stainless tube reactor and heated by a salt-bath. Factors affecting the decomposition rate of 4-octoxy-4′-cyanobiphenyl were evaluated with HPLC. The decomposed liquid products were characterized by GC-MS. Under optimized conditions i.e., 0.2 mL H{sub 2}O{sub 2} supply, pH value 6, temperature 275 °C and reaction time 5 min, 97.6% of 4-octoxy-4′-cyanobiphenyl was decomposed into simple and environment-friendly products. Based on the mechanism analysis and products characterization, a possible hydrothermal decomposition pathway was proposed. The results indicate that hydrothermal technology is a promising choice for liquid crystal treatment.

  1. Preparation of hydrotalcite-like compounds by hydrothermal synthesis

    Czech Academy of Sciences Publication Activity Database

    Zima, Vítězslav; Melánová, Klára; Beneš, Ludvík

    Bratislava : Slovak Academy of Science, 2002. s. xx. [Solid State Chemistry 2002. 07.08.2002-12.08.2002, Bratislava] R&D Projects: GA ČR GA202/01/0520 Keywords : layered double hydroxides * hydrothermal synthesis Subject RIV: CA - Inorganic Chemistry

  2. VO2(B) nanospheres: Hydrothermal synthesis and electrochemical properties

    International Nuclear Information System (INIS)

    Monodisperse VO2(B) nanospheres with an average size of 100 nm were synthesized by hydrothermal method. Experiments showed that the surfactant octadecyl-amine played an important role during the formation of the nanospheres, and possible mechanism was suggested. Moreover, the potential uses of VO2 nanospheres were primarily probed as electrodes for lithium-ion batteries.

  3. Hydrothermal mixing: Fuel for life in the deep-sea

    Science.gov (United States)

    Hentscher, M.; Bach, W.; Amend, J.; McCollom, T.

    2009-04-01

    Deep-sea hydrothermal vent systems show a wide range of fluid compositions and temperatures. They reach from highly alkaline and reducing, like the Lost City hydrothermal field, to acidic and reducing conditions, (e. g., the Logatchev hydrothermal field) to acidic and oxidizing conditions (e. g., island arc hosted systems). These apparently hostile vent systems are generally accompanied by high microbial activity forming the base of a food-web that often includes higher organisms like mussels, snails, or shrimp. The primary production is boosted by mixing of chemically reduced hydrothermal vent fluids with ambient seawater, which generates redox disequilibria that serve as energy source for chemolithoautotrophic microbial life. We used geochemical reaction path models to compute the affinities of catabolic (energy-harvesting) and anabolic (biosynthesis) reactions along trajectories of batch mixing between vent fluids and 2 °C seawater. Geochemical data of endmember hydrothermal fluids from 12 different vent fields (Lost City, Rainbow, Logatchev, TAG, EPR 21 °N, Manus Basin, Mariana Arc, etc.) were included in this reconnaissance study of the variability in metabolic energetics in global submarine vent systems. The results show a distinction between ultramafic-hosted and basalt-hosted hydrothermal systems. The highest energy yield for chemolithotrophic catabolism in ultramafic-hosted hydrothermal systems is reached at low temperature and under slightly aerobic to aerobic conditions. The dominant reactions, for example at Rainbow or Lost City, are the oxidation of H2, Fe2+ and methane. At temperatures >60 °C, anaerobic metabolic reactions, e. g., sulphate reduction and methanogenesis, become more profitable. In contrast, basalt-hosted systems, such as TAG and 21 °N EPR uniformly indicate H2S oxidation to be the catabolically dominant reaction over the entire microbial-relevant temperature range. Affinities were calculated for the formation of individual cellular

  4. Sulfur isotopic composition of seafloor hydrothermal sediment from the Jade hydrothermal field in the central Okinawa Trough and its geological significance

    Institute of Scientific and Technical Information of China (English)

    曾志刚; 李军; 蒋富清; 翟世奎; 秦蕴珊; 侯增谦

    2002-01-01

    --Eighteen samples of hydrothermal sediments from the Jade hydrotherrnal field in the central Okinawa Trough have been analyzed. Sulfur isotopic values for 10 sulfide samples vary from 5.2 ×10-3to 7.2× 10-3, δ34S valUes for 7 sulfate samples vary from 16.3 × 10-3 to 22.3 × 10-3, and 1 native sulphur sample has a δ34S value of 8.2 × 10-3. The major sources of sulfur for hydrothermal sediment are intermediate to acid volcanic rocks and sea water sulfate, and it is possible that the partial sulfur of hydrothermal sediment is from the pelagic sediment by the interaction between hydrothermal fluid and sediment. The reasons of causing the distinct differences in sulfur isotopic values for sulfide samples from hydrothermal sediment ( compared with other hydrothermal fields), are the differences in the sources of sulfur, the magmatic activity and the tectonic evolution in different hydrothermal fields. The sulfur evolution is a long and complex process in the seafloor hydrothermal system, involving the ascending of heating sea water, the interaction between fluid and volcanic rocks, the mixing of sea water sulfate and sulfur from intermediate to acid volcanic rocks, and the fluid/pelagic-sediment interaction. And the interaction between sea water and intermediate to acid volcanic rocks is an important mechanism for the sulfur evolution in the Jade hydrothermal field.

  5. Radon loss from barite in submarine hydrothermal sulfide deposits

    Science.gov (United States)

    Uchida, A.; Toyoda, S.; Ishibashi, J.

    2012-12-01

    Determining the ages of the hydrothermal deposit will greatly contribute the studies of temporal change of submarine hydrothermal activities, as they are essential factors for ore formation and for the biological systems sustained by the chemical species arising from hydrothermal activities. The dating methods available for this purpose includes disequilibrium among 238U, 234U, and 230Th in sufide minerals, between 226Ra and 210Pb, and 228Ra and 228Th in barite (BaSO4) contained in the deposits, and ESR (electron spin resonance) using SO3- radical in barite. In applying these dating methods, a closed system is assumed, where radioactive nuclei decay following the law of physics but are not mobile out of the mineral. However, White and Rood (2001) reported that 3 to 20% of 222Rn is lost from barite crystal, which are used for casing of mining on the land. As 222Rn loss in barite greatly affects the dating results of 226}Ra-{210Pb method and ESR dating method in which radioactive equilibrium is assumed to calculate the dose rate, in the present paper, we investigated {222}Rn loss from the barite crystals contained in hydrothermal sulfide deposits. The radioactive nuclei, 210Pb and 214Bi were measured by the low background pure germanium gamma ray spectrometer at Okayama University of Science. A Pitchblend Uraninite (UO2) mixed with NaCl was used as the equilibrated standard. The barite crystals extracted from hydrothermal sulfide deposits taken in South Mariana Trough are also crused and mixed with NaCl. The mixed powder was packed in a thin stainless container which prevent from Rn loss, before the measurements. The measurements for 24 hours were repeated every day for 20 days. As results, it was found that the peak intensities of 210Pb and 214Bi did not change with time, meaning no Rn loss.

  6. Hydrothermal treatment of titanium alloys for the enhancement of osteoconductivity

    International Nuclear Information System (INIS)

    The surface wettability of implants is a crucial factor in their osteoconductivity because it influences the adsorption of cell-attached proteins onto the surface. In this study, a single-step hydrothermal surface treatment using distilled water at a temperature of 180 °C for 3 h was applied to titanium (Ti) and its alloys (Ti–6Al–4V, Ti–6Al–7Nb, Ti–29Nb–13Ta–4.6Zr, Ti–13Cr–1Fe–3Al; mass%) and compared with as-polished Ti implants and with implants produced by anodizing Ti in 0.1 M of H3PO4 with applied voltages from 0 V to 150 V at a scanning rate of 0.1 V s−1. The surface-treated samples were stored in a five time phosphate buffered saline (× 5 PBS(−)) solution to prevent increasing the water contact angle (WCA) with time. The surface characteristics were evaluated using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, surface roughness, and contact angle measurement using a 2 μL droplet of distilled water. The relationship between WCA and osteoconductivity at various surface modifications was examined using in vivo tests. The results showed that a superhydrophilic surface with a WCA ≤ 10° and a high osteoconductivity (RB–I) of up to 50% in the cortical bone part, about four times higher than the as-polished Ti and Ti alloys, were provided by the combination of the hydrothermal surface treatment and storage in × 5 of PBS(−). - Highlights: • Hydrothermal treatment in distilled water was applied to titanium alloys. • Surface characteristics and osteoconductivity by in vivo test were evaluated. • Water contact angles of titanium alloys were decreased by hydrothermal treatment. • Osteoconductivity of titanium alloys improved notably by hydrothermal treatment after stored in × 5 of PBS (−)

  7. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  8. Comparación entre el componente evaluativo en un ambiente de aprendizaje basado en juegos digitales y el componente evaluativo tradicional, en el tema División Celular para grado séptimo: Estudio de caso en la Institución Educativa CASD José María Espinosa Prieto del municipio de Medellín

    OpenAIRE

    Ortega Gamboa, Liseth

    2015-01-01

    Resumen: Este trabajo consiste en una propuesta metodológica basada en juegos digitales para el concepto de división celular en el grado séptimo de básica secundaria de la Institución Educativa CASD José María Espinosa Prieto en la ciudad de Medellín, la cual busca comparar las prácticas de la evaluación tradicional con la evaluación que se puede realizar en un ambiente digital basado en un videojuego; donde los estudiantes transformen su concepción de evaluación e interactúen de forma lúdica...

  9. Application of Hydrothermal and Non-Hydrothermal TiO2 Nanoporous Materials as New Adsorbents for Removal of Heavy Metal Ions from Aqueous System

    Directory of Open Access Journals (Sweden)

    Mansoor Anbia

    2016-06-01

    Full Text Available Hydrothermal and non-hydrothermal spherical TiO2 nanoporous with crystalline framework were prepared by sol-gel method. The Crystalline structures, morphologies and surface texturing of materials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM and N2 adsorption-desorption isotherms. The Hydrothermal spherical TiO2 nanoporous was found to have a narrow and strong pore size distribution peaks with average of 37.8 Å and pore volume of 0.41 cm3/g and the (Brunauer–Emmett–TellerBET specific surface area of 365 m2/g. Hydrothermal and non-hydrothermal spherical TiO2 nanoporous have been used as adsorbent to study of the adsorption behavior of Pb(II, Co(II and Ni(II ions from aqueous system in a batch system. Effect of equilibrium time on adsorption Pb(II, Co(II and Ni(II ions on these adsorbent was studied The results show that the shaking time 0.5 to 10h has no serious effect on the percentage of ions removal, and the adsorption is fast in all cases. The maximum uptake capacities of Hydrothermal and non-hydrothermal spherical TiO2 nanoporous was calculated. Both hydrothermal and non-hydrothermal TiO2 nanoporous materials were found to have very good potential as new adsorbents in removal of these ions. In batch systems the maximum uptake capacities of Pb(II, Ni(II and Co(II on the hydrothermal and non-hydrothermal TiO2 nanoporous materials was Co(II > Pb(II > Ni(II and Co(II > Ni(II > Pb(II, respectively.

  10. Hydrothermal vents is Lake Tanganyika, East African Rift system

    Energy Technology Data Exchange (ETDEWEB)

    Tiercelin, J.J. [Universite de Bretagne Occidentale, Brest (France); Pflumio, C.; Castrec, M. [Universite Paris VI, Paris (France)] [and others

    1993-06-01

    Sublacustrine hydrothermal vents with associated massive sulfides were discovered during April 1987 at Pemba and Cape Banza on the Zaire side of the northern basin of Lake Tanganyika, East African Rift system. New investigations by a team of ten scuba divers during the multinational (France, Zaire, Germany, and Burundi) TANGANYDRO expedition (August-October 1991) found hydrothermal vents down to a depth of 46 m along north-trending active faults bounding the Tanganyika rift on the western side. Temperatures from 53 to 103 {degrees}C were measured in hydrothermal fluids and sediments. Veins of massive sulfides 1-10 cm thick (pyrite and marcasite banding) were found associated with vents at the Pemba site. At Cape Banza, active vents are characterized by 1-70-cm-high aragonite chimneys, and there are microcrystalline pyrite coatings on the walls of hydrothermal pipes. Hydrothermal fluid end members show distinctive compositions at the two sites. The Pemba end member is a NaHCO{sub 3}-enriched fluid similar to the NaHCO{sub 3} thermal fluids form lakes Magadi and Bogoria in the eastern branch of the rift. The Cape Banza end member is a solution enriched in NaCl. Such brines may have a deep-seated basement origin, as do the Uvinza NaCl brines on the eastern flank of the Tanganyika basin. Geothermometric calculations have yielded temperatures of fluid-rock interaction of 219 and 179 {degrees}C in the Pemba and Cape Banza systems, respectively. Abundant white or reddish-brown microbial colonies resembling Beggiatoa mats were found surrounding the active vents. Thermal fluid circulation is permitted by opening of cracks related to 130{degrees}N normal-dextral faults that intersect the north-south major rift trend. The sources of heat for such hydrothermal systems may relate to the existence of magmatic bodies under the rift, which is suggested by the isotopic composition of carbon dioxide released at Pemba and Cape Banza. 21 refs., 2 figs.

  11. Hydrothermal plumes in the NE Lau basin: A regional perspective

    Science.gov (United States)

    Walker, S. L.; Baker, E. T.

    2013-12-01

    Exploration for mineral resources and the presence of an extensive plume of excess 3He centered at 1750 m water depth in the Samoa-Tonga-Fiji region (Lupton, 2004) have motivated exploration for active hydrothermal vent sites in the NE Lau basin during the past decade. The region is tectonically complex with back-arc spreading centers, rift zones, and volcanic centers, all of which potentially host active venting and/or active volcanism. To date, 400 km of the three back-arc spreading centers in the NE Lau basin (FRSC, Fonualei Rift and Spreading Center; MTJ, Mangatolu Triple Junction; and NELSC, Northeastern Lau Spreading Center) plus several volcanic centers have been systematically surveyed for hydrothermal plumes using towed CTD or MAPR arrays that include both optical backscatter and oxidation-reduction potential (ORP) sensors. The FRSC, where spreading rates range from 47 mm/a in the south to 85 mm/a in the north, has 5 active sites (plume depths ranging from 1300-2200 m) distributed one every ~40 km over its 200 km length. There is evidence for 4 active sites (plume depths range from 1950-2380 m) along the 150 km combined length of the MTJ segments, however plumes were optically weak (dNTU < 0.02) and except for one location along the northeastern limb, no ORP anomalies were detected. Plumes were observed off-axis to the MTJ at a bathymetric high adjacent to the northeastern limb (1700 m) as well as over the summit of a cratered volcanic edifice east of the central junction (1200-1300 m). The southern segment of the NELSC was the site of an active eruption in 2008 which injected event plumes throughout the water column (900-1600 m depth range) in addition to the chronic plume from the Maka massive sulfide vent site (1500 m). There is evidence for at least two additional active areas along the northern segments of the NELSC (1800-1900 m). Several volcanoes in the region are hydrothermally active ranging from the northernmost volcano on the Tonga arc (Niua

  12. Experimental investigation of single carbon compounds under hydrothermal conditions

    Science.gov (United States)

    Seewald, Jeffrey S.; Zolotov, Mikhail Yu.; McCollom, Thomas

    2006-01-01

    The speciation of carbon in subseafloor hydrothermal systems has direct implications for the maintenance of life in present-day vent ecosystems and possibly the origin of life on early Earth. Carbon monoxide is of particular interest because it represents a key reactant during the abiotic synthesis of reduced carbon compounds via Fischer-Tropsch-type processes. Laboratory experiments were conducted to constrain reactions that regulate the speciation of aqueous single carbon species under hydrothermal conditions and determine kinetic parameters for the oxidation of CO according to the water water-gas shift reaction (CO 2 + H 2 = CO + H 2O). Aqueous fluids containing added CO 2, CO, HCOOH, NaHCO 3, NaHCOO, and H 2 were heated at 150, 200, and 300 °C and 350 bar in flexible-cell hydrothermal apparatus, and the abundances of carbon compounds was monitored as a function of time. Variations in fluid chemistry suggest that the reduction of CO 2 to CH 3OH under aqueous conditions occurs via a stepwise process that involves the formation of HCOOH, CO, and possibly CH 2O, as reaction intermediaries. Kinetic barriers that inhibit the reduction of CH 3OH to CH 4 allow the accumulation of reaction intermediaries in solution at high concentrations regulated by metastable thermodynamic equilibrium. Reaction of CO 2 to CO involves a two-step process in which CO 2 initially undergoes a reduction step to HCOOH which subsequently dehydrates to form CO. Both reactions proceed readily in either direction. A preexponential factor of 1.35 × 10 6 s -1 and an activation energy of 102 kJ/mol were retrieved from the experimental results for the oxidation of CO to CO 2. Reaction rates amongst single carbon compounds during the experiments suggest that ΣCO 2 (CO 2 + HCO 3- + CO 32-), CO, ΣHCOOH (HCOOH + HCOO -), and CH 3OH may reach states of redox-dependent metastable thermodynamic equilibrium in subseafloor and other hydrothermal systems. The abundance of CO under equilibrium conditions

  13. Ecological Impacts of the Cerro Grande Fire: Predicting Elk Movement and Distribution Patterns in Response to Vegetative Recovery through Simulation Modeling October 2005

    Energy Technology Data Exchange (ETDEWEB)

    S.P. Rupp

    2005-10-01

    In May 2000, the Cerro Grande Fire burned approximately 17,200 ha in north-central New Mexico as the result of an escaped prescribed burn initiated by Bandelier National Monument. The interaction of large-scale fires, vegetation, and elk is an important management issue, but few studies have addressed the ecological implications of vegetative succession and landscape heterogeneity on ungulate populations following large-scale disturbance events. Primary objectives of this research were to identify elk movement pathways on local and landscape scales, to determine environmental factors that influence elk movement, and to evaluate movement and distribution patterns in relation to spatial and temporal aspects of the Cerro Grande Fire. Data collection and assimilation reflect the collaborative efforts of National Park Service, U.S. Forest Service, and Department of Energy (Los Alamos National Laboratory) personnel. Geographic positioning system (GPS) collars were used to track 54 elk over a period of 3+ years and locational data were incorporated into a multi-layered geographic information system (GIS) for analysis. Preliminary tests of GPS collar accuracy indicated a strong effect of 2D fixes on position acquisition rates (PARs) depending on time of day and season of year. Slope, aspect, elevation, and land cover type affected dilution of precision (DOP) values for both 2D and 3D fixes, although significant relationships varied from positive to negative making it difficult to delineate the mechanism behind significant responses. Two-dimensional fixes accounted for 34% of all successfully acquired locations and may affect results in which those data were used. Overall position acquisition rate was 93.3% and mean DOP values were consistently in the range of 4.0 to 6.0 leading to the conclusion collar accuracy was acceptable for modeling purposes. SAVANNA, a spatially explicit, process-oriented ecosystem model, was used to simulate successional dynamics. Inputs to the

  14. Prácticas de sacrificio en el Cerro de la Mesa (Alcolea de Tajo, Toledo: el depósito ritual de la Casa 1

    Directory of Open Access Journals (Sweden)

    Ana CABRERA DÍEZ

    2014-06-01

    Full Text Available Los depósitos con restos óseos animales enterrados bajo el pavimento en ámbitos domésticos forman parte de prácticas rituales bien conocidas en la Protohistoria peninsular, tradicionalmente asociadas a la fundación o remodelación de nuevos edificios o a ritos vinculados a la propiciación y la fertilidad. Aunque los ejemplos mejor estudiados se encuentran en la zona levantina, el fenómeno también se conoce en yacimientos del interior. Este artículo tiene por objeto presentar un depósito ritual excavado en el poblado vetón del Cerro de la Mesa, en el valle medio del Tajo, cuyas características formales lo emparentan con las ofrendas domésticas de la zona ibérica. Se trata de un hoyo situado en el umbral de la Casa 1, que contiene los restos seleccionados de varios ovinos y un pequeño cuenco cerámico colocado en posición invertida. El análisis de los restos óseos, el contenido del cuenco y el estudio del contexto arqueológico en que se situaba el depósito han permitido relacionarlo con prácticas de sacrificio y libación dentro del marco de la religiosidad vetona. Este trabajo pretende igualmente contribuir a la formación de un corpus peninsular de inhumaciones rituales de animales en contextos domésticos, que impulse el adecuado estudio de la ritualidad protohistórica.

  15. Perfil infectológico de poblaciones mapuche de Cerro Policía y Aguada Guzmán de la provincia de Río Negro

    Directory of Open Access Journals (Sweden)

    Rey, Jorge Alberto

    1996-01-01

    Full Text Available Nuestro trabajo analiza la prevalencia de marcadores de algunas infecciones que afectan las poblaciones mapuche de Cerro Policía (CP y Aguada Guzmán (AG en la Prov. de Río Negro. Los estudios incluídos son: determinación de anticuerpos anti-Treponema pallidum, anti-Trypanosoma cruzii, anti-Echinococcus granulosus, antígeno de superficie de la Hepatitis B (HBsAg, anticuerpos contra el core de la Hepatitis B (anti-HBc, anticuerpos contra el virus de la Hepatitis A (anti-HAV. Se estudiaron 160 muestras en CP y 83 en AG. Los resultados muestran alta prevalencia para anti-HAV en CP (89.2% y en AG (77.1% y para hidatidosis (10.6% y 9.6% respectivamente. Se hallaron valores nulos o bajos para sífilis (CP: 0.0 % y AG:2.4%. La prevalencia para Chagas fue del 10% en CP y 0.0% en AG. Los datos para Hepatitis B fueron nulos o bajos: HBsAg (CP:0.0% y AG:1.2% y anti-HBc(CP:0.6% y AG:0.0%. Los resultados indican que, aún estando estas dos poblaciones tan próximas muestran diferencias en los perfiles de los marcadores serológicos estudiados. Al comparar las tasas de prevalencia con las de otras poblaciones de América, cada una presenta un perfil diferente que depende de la población y del agente infeccioso considerado.

  16. Evaluación del estado de conservación de las microcuencas pertenecientes a los Cerros Orientales de Chía, Cundinamarca, Colombia

    Directory of Open Access Journals (Sweden)

    Arévalo Santos Carolina

    2006-06-01

    Full Text Available El trabajo se realizó en colaboración con la Alcaldía Municipal de Chía, Cundinamarca, Colombia, con el fin de
    aproximarnos al estado de conservación de las microcuencas localizadas sobre la cota de altitud 2.600-3.200 msnm, en las veredas de Yerbabuena y Fusca, donde se identificaron cuatro microcuencas de interés: Mana- Yerbabuena, Coseteja, Fusca y Honda-Pan de Azúcar. El documento final se presenta como un instrumento para el conocimiento de los cerros Orientales de Chía a una escala municipal, cuyo enfoque establece los diferentes tipos de cobertura de vegetación existentes como indicador del estado actual de las microcuencas y evidencia situaciones críticas que pueden propiciar su total degradación. Los resultados permiten concluir que los procesos de transformación son bastante intensos, debido básicamente a la acción antrópica que ha hecho de los procesos urbanísticos el factor de amenaza más significativo, que ha conducido a la pérdida acelerada de la vegetación, apertura de vías de acceso, uso inadecuado de las fuentes hídricas etc. El producto principal de este  análisis es la generación de un mapa de áreas de interés ambiental que proponemos deben ser proyectadas ya sea
    para fines de conservación, restauración, recuperación y áreas cuyo manejo de conflictos debe ser prioridad. La
    importancia de establecer el estado de conservación deriva de la necesidad de proporcionar bases para el desarrollo de planes de manejo ambiental.

  17. Cerros Amarillos: un sistemade alteración de tipo pórfiro de edad Miocena Superior, Cordillera Principal,Provincia de Mendoza

    Directory of Open Access Journals (Sweden)

    Nora Rubinstein

    2009-11-01

    Full Text Available Se describe un área de alteración aflorante en laregión de Cerros Amarillos, ubicada en el curso superior del río Atuel, en laCordillera Principal del sur de Mendoza (35°S, 70°O. La zona de alteraciónestá espacialmente asociada a la Formación Huincán en facies dacítica (Miocenosuperior y está caracterizada por un estadio hidrotermal temprano representadopor alteración potásica con una asociación de biotita-magnetita. A ésta sesobreimpone una paragénesis compuesta por sericita-sílice-carbonato a la que seasocia alteración albítica. Esta fase tardía correspondería a una asociación dealbita-sericita de alto nivel que ocurre a profundidades someras dentro delsistema y es anterior a la etapa fílica. Por otra parte también seidentificaron en el área de alteración cuerpos de endoskarn que corresponden abrechas piroxénicas y vetas de plagioclasa-piroxeno. Las paragénesis dealteración reconocidas permiten asimilarlas, de forma preliminar, a las de lossistemas tipo pórfiro con alteración sódica que, de acuerdo a las relacionesestratigráficas y la información geocronológica existente se vincularíagenéticamente al magmatismo del Mioceno superior.

  18. Apresentacão do Projeto de extensão universitaria "Fortalecimento das Capacidades das Educadoras do Programa CAIF no estado de Cerro Largo-Uruguai"

    Directory of Open Access Journals (Sweden)

    Mariana Porta Galván

    2015-12-01

    Full Text Available Dentro de la línea de investigación Estado, políticas sociales y ciudadanía en frontera, es relevante conocer la realidad de las políticas sociales orientadas a la primera infancia y sus implementaciones. Esta ponencia presenta un proyecto de extensión universitaria realizada con los centros CAIF de Cerro Largo con el propósito de fortalecer las prácticas de los operadores sociales de estos centros, a partir de las siguientes preguntas: ¿Qué características asume la implementación de esta política pública en un departamento fronterizo? ¿Qué desafíos plantea a sus operadores? Consideramos que la implementación de una política social, más allá de la forma en que se concibe, diseña y expresa en sus documentos, implica un proceso de apropiación que conlleva interpretaciones y adaptaciones que se manifiestan en prácticas. Estas, a su vez, responden a disposiciones, hábitos y saberes (entendidos como conocimientos tácitos y explícitos de los operadores involucrados, en un vínculo directo con la cultura propia de los contextos en los que se desarrollan. En ese proceso de implementación y sus múltiples niveles de gestión, se encuentran los desafíos a los cuales pretendemos aportar desde una propuesta de capacitación de operadores, que responda a la diversidad de cada territorio y de cada contexto social.

  19. Hydrothermal Habitats: Measurements of Bulk Microbial Elemental Composition, and Models of Hydrothermal Influences on the Evolution of Dwarf Planets

    Science.gov (United States)

    Neveu, Marc Francois Laurent

    Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life. Such environments include hydrothermal systems, spatially-confined systems where hot aqueous fluid circulates through rock by convection. I sought to characterize hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA, by measuring their bulk elemental composition. To do so, one must minimize the contribution of non-biological material to the samples analyzed. I demonstrate that this can be achieved using a separation method that takes advantage of the density contrast between cells and sediment and preserves cellular elemental contents. Using this method, I show that in spite of the tremendous physical, chemical, and taxonomic diversity of Yellowstone hot springs, the composition of microorganisms there is surprisingly ordinary. This suggests the existence of a stoichiometric envelope common to all life as we know it. Thus, future planetary investigations could use elemental fingerprints to assess the astrobiological potential of hydrothermal settings beyond Earth. Indeed, hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core. I enhance a dwarf planet evolution code, including the effects of core fracturing and hydrothermal circulation, to demonstrate that dwarf planets likely have undergone extensive water-rock interaction. This supports observations of aqueous products on their surfaces. I simulate the alteration of chondritic rock by pure water or cometary fluid to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the

  20. Mechanochemical-hydrothermal synthesis and characterization of fluoridated hydroxyapatite

    International Nuclear Information System (INIS)

    Fluoridated hydroxyapatite (FHAp) was successfully synthesized from the starting materials of CaCO3, CaHPO4.2H2O, and CaF2 via a mechanochemical-hydrothermal route. X-ray diffraction, infrared spectroscopy, surface area measurements, and scanning electron microscopy identified the resultant powders as FHAp nanocrystals with the specific surface areas of up to 114.72 m2/g. The mechanism study revealed that under such mechanochemical-hydrothermal conditions the formation reactions of FHAp were completed in two stages. The starting materials firstly reacted into a poorly crystallized calcium-deficient apatite and the complete incorporation of fluoride ions into apatite occurred in the second stage

  1. Formic acid production from carbohydrates biomass by hydrothermal reaction

    International Nuclear Information System (INIS)

    The formation of formic acid or formate salts by hydrothermal oxidation of model biomass materials (glucose, starch and cellulose) was investigated. All experiments were conducted in a batch reactor, made of SUS 316 tubing, providing an internal volume of 5.7 cm3. A 30 wt% hydrogen peroxide aqueous solution was used as an oxidant. The experiments were carried out with temperature of 2500C, reaction time varying from 0.5 min to 5 min, H2O2 supply of 240%, and alkaline concentration varying from 0 to 1.25 M. Similar to glucose, in the cases of the oxidation of hydrothermal starch and cellulose, the addition of alkaline can also improve the yield of formic acid. And the yield were glucose>starch> cellulose in cases of with or without of alkaline addition.

  2. Fabrication Of Titania Nanotubes By A Modified Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Meor Yusoff M.S

    2011-09-01

    Full Text Available The main setback of the fabrication of titania nanotubes by the hydrothermal method is the long dissolution time and the usage of highly concentrated NaOH. Our group has managed to develop a modified hydrothermal process that is capable of fabricating titania nanotubes in a shorter timespan while using a more dilute NaOH solution. The study shows that the titania nanotubes starts to form from 7 hours of dissolution, and more nanotubes is produced as the dissolution duration is extended. Similarly, we are able to produce titania nanotubes from a more dilute NaOH solution than those reported earlier. By varying the parameters of the fabrication process, different nanostructures can be obtained such as single, branched nanowires and nanobelts.

  3. Flow and permeability structure of the Beowawe, Nevada hydrothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Faulder, D.D. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States); Johnson, S.D.; Benoit, W.R. [Oxbow Power Services, Inc., Reno, NV (United States)

    1997-05-01

    A review of past geologic, geochemical, hydrological, pressure transient, and reservoir engineering studies of Beowawe suggests a different picture of the reservoir than previously presented. The Beowawe hydrothermal contains buoyant thermal fluid dynamically balanced with overlying cold water, as shown by repeated temperature surveys and well test results. Thermal fluid upwells from the west of the currently developed reservoir at the intersection of the Malpais Fault and an older structural feature associated with mid-Miocene rifting. A tongue of thermal fluid rises to the east up the high permeability Malpais Fault, discharges at the Geysers area, and is in intimate contact with overlying cooler water. The permeability structure is closely related to the structural setting, with the permeability of the shallow hydrothermal system ranging from 500 to 1,000 D-ft, while the deeper system ranges from 200 to 400 D-ft.

  4. Artificial Bee Colony Optimization for Short-Term Hydrothermal Scheduling

    Science.gov (United States)

    Basu, M.

    2014-12-01

    Artificial bee colony optimization is applied to determine the optimal hourly schedule of power generation in a hydrothermal system. Artificial bee colony optimization is a swarm-based algorithm inspired by the food foraging behavior of honey bees. The algorithm is tested on a multi-reservoir cascaded hydroelectric system having prohibited operating zones and thermal units with valve point loading. The ramp-rate limits of thermal generators are taken into consideration. The transmission losses are also accounted for through the use of loss coefficients. The algorithm is tested on two hydrothermal multi-reservoir cascaded hydroelectric test systems. The results of the proposed approach are compared with those of differential evolution, evolutionary programming and particle swarm optimization. From numerical results, it is found that the proposed artificial bee colony optimization based approach is able to provide better solution.

  5. Hydrothermal synthesis and physicochemical properties of ruthenium(0) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dikhtiarenko, A., E-mail: dikhtiarenkoalla@uniovi.es [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Khainakov, S.A.; Garcia, J.R.; Gimeno, J. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Pedro, I. de; Fernandez, J. Rodriguez [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Ruthenium nanoparticles were synthesized by hydrothermal technique. Black-Right-Pointing-Pointer The average size of the nanoparticles are depend on the reducing agent used. Black-Right-Pointing-Pointer The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the ruthenium(0) nanoparticles. - Abstract: The synthesis of ruthenium nanoparticles in hydrothermal conditions using mild reducing agents (succinic acid, ascorbic acid and sodium citrate) is reported. The shape of the nanoparticles depends on the type of the reducing agent, while the size is more influenced by the pH of the medium. The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the nanoparticles.

  6. Sustainability and dynamics of outcrop-to-outcrop hydrothermal circulation

    Science.gov (United States)

    Winslow, Dustin M.; Fisher, Andrew T.

    2015-06-01

    Most seafloor hydrothermal circulation occurs far from the magmatic influence of mid-ocean ridges, driving large flows of water, heat and solutes through volcanic rock outcrops on ridge flanks. Here we create three-dimensional simulations of ridge-flank hydrothermal circulation, flowing between and through seamounts, to determine what controls hydrogeological sustainability, flow rate and preferred flow direction in these systems. We find that sustaining flow between outcrops that penetrate less-permeable sediment depends on a contrast in transmittance (the product of outcrop permeability and the area of outcrop exposure) between recharging and discharging sites, with discharge favoured through less-transmissive outcrops. Many simulations include local discharge through outcrops at the recharge end of an outcrop-to-outcrop system. Both of these characteristics are observed in the field. In addition, smaller discharging outcrops sustain higher flow rates than larger outcrops, which may help to explain how so much lithospheric heat is extracted globally by this process.

  7. Isotopic study of some fossil and actual hydrothermal systems

    International Nuclear Information System (INIS)

    Oxygen and hydrogen isotopic compositions of rocks from the INAG no 1 drillhole provide evidence of a fossil hydrothermal system in the Ceyssat region of the Massif Central. Oxygen isotope temperatures for the mineral paragenesis are about 2750C and the water is of marine origin. Measurements have also been made of delta13C values of dissolved carbon and gaseous CO2 from several hot springs in the Pyrenees and Massif Central. The carbon isotopic composition of the total systems have been calculated from the gas-liquid ratios at the emergence sites and these results are discussed in terms of the origin of the carbon. Most of the hydrothermal carbon is of deep origin. The observed variations in isotopic compositions may be explained by the behavior of the fluids during their ascent to the surface

  8. FACTS BASED CONTROLLER FOR INTERCONNECTED HYDROTHERMAL POWER SYSTEM

    Directory of Open Access Journals (Sweden)

    Ravi Shankar

    2012-04-01

    Full Text Available This research paper introduce the FACTS based decentralized controller for load frequency control of two area interconnected hydrothermal power system considering the combined effect of RFB ( Redox Flow Batteries and TCPS ( Thyristor Control Phase Shifter as a FACTS device which is incorporated with tie-line power flowof the given system. The proposed controller is design using genetic algorithm based integral controller in which Integral Square Error (ISE criterion is consider for the optimization of the system error. This proposed controller is implemented into the two area interconnected hydrothermal power system and its different performance is studies with and without RFB and TCPS control scheme. This studies revels that the proposed controller gives better transient responses and helps in better stabilizing frequency response as well as improve the tie line power flow of the system.

  9. Controlled growth of silver nanoparticles in a hydrothermal process

    Institute of Scientific and Technical Information of China (English)

    Juan Zou; Yao Xu; Bo Hou; Dong Wu; Yuhan Sun

    2007-01-01

    A two-step synthesis was used to control the shape of silver nanoparticles. First, a few spherical silver nanoparticles, ~10 nm in size, were prepared via reduction of Ag+ ions in aqueous Ag(NH3)2NO3 by poly(N-vinyl-2-pyrrolidone) (PVP). Then, in a subsequent hydrothermal treatment,the remaining Ag+ ions were reduced by PVP into polyhedral nanoparticles, or larger spherical nanoparticles formed from the small spherical seed silver nanoparticles in the first step. The morphology and size of the resultant particles depend on the hydrothermal temperature, PVP/Ag molar ratio and concentration of Ag+ ions. By using UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD), the possible growth mechanism of the silver nanoparticles was discussed.

  10. Thermodynamic analysis of hydrogen production via hydrothermal gasification of hexadecane

    KAUST Repository

    Alshammari, Yousef M.

    2012-04-01

    This work reports the equilibrium behaviour of the hydrothermal gasification of hexadecane, a heavy saturate model compound, under non-oxidative isothermal and oxidative adiabatic conditions, using the Peng-Robinson equation of state and the direct minimisation of Gibbs free energy employed within the Aspen HYSYS. This modelling enabled establishing both the limits and optimum conditions at which the hydrogen molar yield may be theoretically maximised. The effects of parameters including the reactor isothermal temperature, pressure, water to carbon ratio, and oxygen to carbon ratio on the molar yields of produced gaseous species were analysed. The model has been validated by comparing its results with different reported modelling and experimental data under identical conditions which resulted in a good agreement. The results reported in this work show the potential of achieving economic yields of hydrogen and syngas from liquid hydrocarbons under downhole hydrothermal conditions. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

  11. INFLUENCE OF REACTION CONDITIONS ON LIGNIN HYDROTHERMAL TREATMENT

    Directory of Open Access Journals (Sweden)

    JalelLabidi

    2014-04-01

    Full Text Available Organosolv lignin, obtained from olive tree pruning under optimised conditions, was subjected to a hydrothermal depolymerisation process catalysed by sodium hydroxide. The depolymerisation of lignin was carried out at 300 ºC using different reaction times (20, 40, 60, 70, 80, 90 and 100 min in order to study the influence of this parameter on lignin depolymerisation. The resulting products (oil and residual lignin were measured and analysed by different techniques (GC/MS, HPSEC and pyrolysis-GC/MS in order to determine their nature and composition. Coke was also formed, at a lower quantity, incompetitive repolymerisation reactions during the lignin hydrothermal treatment. The maximum oil yield and concentration of monomeric phenolic compounds was obtained after80 min of reaction time. The highest reaction time studied (100 min had the worst results with the lowest oil yield and highest coke production.

  12. Colorado's hydrothermal resource base: an assessment

    Energy Technology Data Exchange (ETDEWEB)

    Pearl, R.H.

    1981-01-01

    As part of its effort to more accurately describe the nations geothrmal resource potential, the US Department of Energy/Division of Geothermal Energy contracted with the Colorado Geological survey to appraise the hydrothermal (hot water) geothermal resources of Colorado. Part of this effort required that the amount of energy that could possibly be contained in the various hydrothermal systems in Colorado be estimated. The findings of that assessment are presented. To make these estimates the geothermometer reservoir temperatures estimated by Barrett and Pearl (1978) were used. In addition, the possible reservoir size and extent were estimated and used. This assessment shows that the total energy content of the thermal systems in Colorado could range from 4.872 x 10{sup 15} BTU's to 13.2386 x 10{sup 15} BTU's.

  13. Naked in toxic fluids: A nudibranch mollusc from hydrothermal vents

    Science.gov (United States)

    Valdés, Ángel; Bouchet, Philippe

    1998-01-01

    A new species of the nudibranch genus Dendronotus (Mollusca, Opisthobranchia) is reported from a hydrothermal vent at the Lucky Strike area, on the Mid-Atlantic Ridge. This is the first species of nudibranch recorded with certainty from a vent site. Other species of Dendronotus are distributed in temperate waters on the continental shelf of the northern hemisphere. Two factors that probably account for the occurrence of a nudibranch in this hydrothermal field are that the Lucky Strike area presents potential hydroid prey, and that nudibranchs apparently inhabit a lower activity area. It is hypothesized that the new species, which lacks eyes, is a permanent resident of vent fields on the Mid-Atlantic Ridge, but is probably not restricted to that environment.

  14. Understanding hydrothermal carbonization of mixed feedstocks for waste conversion

    Science.gov (United States)

    Lu, Xiaowei

    Hydrothermal carbonization (HTC) is an environmentally beneficial means to convert waste materials to value-added solid and liquid products with minimal greenhouse gas emission. Research is lacking on understanding the influence of critical process conditions on product formation and environmental implication associated with HTC of waste streams. This work was conducted to determine how reaction conditions and heterogeneous compound mixtures (representative of municipal wastes) influence hydrothermal carbonization processes. The specific experiments include: (1) determine how carbonization product properties are manipulated by controlling feedstock composition, process conditions, and catalyst addition; (2) determine if carbonization of heterogeneous mixtures follows similar pathways as that with pure feedstocks; and (3) evaluate and compare the carbon and energy-related implications associated with carbonization products with those associated with other common waste management processes for solid waste.

  15. Andesita Cerro Bola: Nueva unidad vinculada al magmatismo mioceno de la Cordillera de Olivares, San Juan, Argentina (30°35´S; 69°30´O

    Directory of Open Access Journals (Sweden)

    A.F. Wetten

    2005-03-01

    Full Text Available El área de estudio se halla en la zona de Tocota, inmediatamente al este de la Cordillera de Olivares, en el borde oriental de la Cordillera Frontal, provincia de San Juan. En ella se encuentran unidades ígneas y sedimentarias del ciclo gondwánico, las que fueron intruidas y cubiertas en relación discordante por cuerpos subvolcánicos y volcánicos asignados anteriormente al ciclo ándico en sentido amplio, los cuales constituyen el principal objeto del presente estudio. Estos cuerpos han sido mapeados a fin de poder caracterizarlos adecuadamente, en el contexto estratigráfico de la región. Los afloramientos de interés han sido reconocidos en el cerro Bola y alrededores, donde se observan distribuidos irregularmente, cubriendo un área superior a 5 km². Las rocas, de coloración gris clara y composición andesítica - fenoandesítica, presentan estructuras de domo y colada. Estos afloramientos serían correlacionables con la unidad volcánica Pircas (Mioceno, la que aflora al oeste, y conformarían un evento magmático posterior al de pórfidos de diferente composición situados tanto en el arroyo Chita como en el cerro Divisadero. La extensión del área involucrada, la uniformidad litológica, el bajo grado de alteración y una edad radimétrica obtenida por el método K/Ar, fueron considerados para proponer a estas volcanitas como una unidad litoestratigráfica de edad miocena superior, con la denominación de Andesita Cerro Bola.

  16. Geochemical behavior of rare earth elements associated with hydrothermal alteration. Implication for the migration and retardation of Am and Cm in hydrothermal system

    International Nuclear Information System (INIS)

    Rare earth element (REE) contents of hydrothermally altered dacitic and basaltic rocks in the Kuroko mining area were analyzed. It was found that geochemical features of REE (Light REE/Total REE ratio, La/Sm ratio, Eu anomaly) are related to K2O index (=K2O/(K2O+Na2O+CaO+MgO)x100) and oxygen isotopic composition (δ18O). This relation indicates that LREE (light rare earth element) did not remove from the rocks to hydrothermal solution and were probably added to the rocks from hydrothermal solution at and near the site of hydrothermal ore deposition. This geochemical behavior of LREE which are considered to be chemical analogue elements for Am and Cm suggests that Am and Cm would not remove from the high level nuclear waste glass if the hydrothermal solution ascent to the disposal site and contacted with the high level nuclear waste. (author)

  17. Hydrothermal system in Southern Grass Valley, Pershing County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Welch, A.H.; Sorey, M.L.; Olmsted, F.H.

    1981-01-01

    Southern Grass Valley is a fairly typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active hydrothermal flow system with an estimated deep aquifer temperature of 163 to 176/sup 0/C. Results of geologic, hydrologic, geophysical and geochemical investigations are discussed in an attempt to construct an internally consistent model of the system.

  18. Air Pollution by Hydrothermal Volcanism and Human Pulmonary Function

    OpenAIRE

    Diana Linhares; Patrícia Ventura Garcia; Fátima Viveiros; Teresa Ferreira; Armindo dos Santos Rodrigues

    2015-01-01

    The aim of this study was to assess whether chronic exposure to volcanogenic air pollution by hydrothermal soil diffuse degassing is associated with respiratory defects in humans. This study was carried in the archipelago of the Azores, an area with active volcanism located in the Atlantic Ocean where Eurasian, African, and American lithospheric plates meet. A cross-sectional study was performed on a study group of 146 individuals inhabiting an area where volcanic activity is marked by active...

  19. Explosive properties of water in volcanic and hydrothermal systems

    OpenAIRE

    Thiery, Régis; Mercury, Lionel

    2009-01-01

    International audience This paper describes, from a thermodynamic point of view, the physicochemical conditions, under which water behaves as an explosive. This phenomenon occurs frequently in hydrothermal and volcanic systems when water is brutally shifted from its initial equilibrium state. Water (either liquid or gas) becomes metastable or unstable and reequilibrates by violent demixing of a liquid-gas mixture. In a first step, a phenomenological approach of metastability is given in a ...

  20. Near shore submarine hydrothermal activity in Bahia Banderas, western Mexico

    OpenAIRE

    F. J. Núñez Cornú; Rosa María Prol Ledesma; A. Cupul Magaña; C. Suárez Plascencia

    2000-01-01

    Shallow submarine hydrothermal activity was detected in the Bahía de Banderas area, Mexico. Volcanic-type tremors were recorded by portable seismological stations onshore. Vent samples suggest a depositional sequence dominated by carbonates in the first stage (calcite and dolomite), followed by apatite and late barite veins. Layers of sequential deposition of sulfides were also observed, and are interpreted as cyclic variations of sulphur fugacity.

  1. Fabrication of agglomerate-free nanopowders by hydrothermal chemical processing

    OpenAIRE

    Schmidt, Helmut K.; Nass, Rüdiger; Burgard, Detlef; Nonninger, Ralph

    1998-01-01

    A chemical processing technique for the fabrication of nanopowders has been developed. The route is based on precipitation processes in solutions, either within aqueous droplets in microemulsions in the presence of surface modifiers like surfactants or by direct precipitation in solutions in the presence of theses surface modifiers or small organic molecules directly bonded to the particle surface. In order to obtain well crystallized or densified particles, a continuous flow hydrothermal pro...

  2. Hydrothermal Synthesis of SnO2 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Shuping Gong; Cong Xu; Huan Liu

    2006-01-01

    SnO2 nanoparticles with the average size of 3.7 nm have been successfully synthesized by hydrothermal method.The particles were characterized by XRD, SEM and TEM. The XRD results show that the products are all at nanometer scale,and the crystallite size increases with increasing of the heat-treatment temperature. The SEM and TEM photographs indicate that the particles are all monodispersed with narrow size distribution.

  3. Hydrothermal liquefaction of Nannochloropsis oceanica in different solvents.

    Science.gov (United States)

    Caporgno, M P; Pruvost, J; Legrand, J; Lepine, O; Tazerout, M; Bengoa, C

    2016-08-01

    Although the hydrothermal liquefaction is considered a promising technology for converting microalgae into liquid biofuels, there are still some disadvantages. This paper demonstrated that the bio-oil yield can be significantly improved by adding alcohols as co-solvents and carrying out the conversion at mild conditions (microalgae (∼75% moisture) and alcohol concentrations which avoid both drying the microalgae and decreasing the amount of microalgae loaded in the reactor. PMID:27155795

  4. Rapid Synthesis of Carbon Dots by Hydrothermal Treatment of Lignin

    OpenAIRE

    Wenxin Chen; Chaofan Hu; Yunhua Yang; Jianghu Cui; Yingliang Liu

    2016-01-01

    A rapid approach has been developed for the fluorescent carbon dots (CDs) by the hydrothermal treatment of lignin in the presence of H2O2. The as-synthesized CDs were found to emit blue photoluminescence with excellent photostability. Moreover, the CDs displayed biocompatibility, low cytotoxicity, and high water solubility properties. Finally, the as-resulted CDs were demonstrated to be excellent probes for bioimaging and biosensing applications.

  5. Rapid Synthesis of Carbon Dots by Hydrothermal Treatment of Lignin

    Directory of Open Access Journals (Sweden)

    Wenxin Chen

    2016-03-01

    Full Text Available A rapid approach has been developed for the fluorescent carbon dots (CDs by the hydrothermal treatment of lignin in the presence of H2O2. The as-synthesized CDs were found to emit blue photoluminescence with excellent photostability. Moreover, the CDs displayed biocompatibility, low cytotoxicity, and high water solubility properties. Finally, the as-resulted CDs were demonstrated to be excellent probes for bioimaging and biosensing applications.

  6. La avalancha de rocas del cerro Los Cardos (37°10´S,70°53´O) en la región norte de la provincia del Neuquén

    OpenAIRE

    E.F. González Díaz; Folguera, A.; Hermanns, R.

    2005-01-01

    Se describe una nueva e importante avalancha de rocas, no reconocida hasta ahora, localizada a unos 25 km al oeste de la población de Andacollo. Muestra dos cicatrices o muescas de desprendimiento, de las cuales la austral es interpretada como la muesca principal de su desprendimiento y se halla al pie del borde occidental de una planicie estructural lávica, sobre cuyo extremo norte se ubica el cerro Los Cardos. Es un complejo movimiento, con numerosas escarpas de arranque internas en la masa...

  7. Evolución petrotectónica del distrito minero Cerro Áspero y modelo de emplazamiento de los depósitos wolframíferos, Córdoba

    OpenAIRE

    D. Mutti; S. González Chiozza

    2005-01-01

    La geología relacionada con la intrusión granítica Cerro Áspero expone en el faldeo oriental de la sierra de Comechingones, mineralización metalífera diseminada y en brechas hidráulicas, conectada genéticamente a un grupo minero integrado por un sistema de enjambres de venas, vetas y mantos cuarzosos con direcciones NNO, ONO y N. La comarca presenta polimetamorfismo y al menos, dos eventos de cizallamiento simple (D3 y D4) y estructuras penetrativas (S2, S3 y S4) que se desarrollaron desde el...

  8. Cuerpos intrusivos asociados a las mineralizaciones polimetálicas del depósito Cerro León, área del anticlinal El Tranquilo, Santa Cruz: evidencias geofísicas

    OpenAIRE

    2008-01-01

    Las características geológicas tales como presencia de cuerpos intrusivos y subvolcánicos someros básicos a intermedios y de las mineralizaciones con alto contenido de sulfuros del área del anticlinal El Tranquilo, son particulares y poco representadas en el macizo del Deseado. El depósito polimetálico vetiforme Cerro León presenta una signatura geoquímica-mineralógica que lo diferencia del clásico modelo epitermal de baja sulfuración característico del macizo del Deseado. Los datos aeromagné...

  9. Estrategias de conservación y restauración aplicadas sobre el registro cerámico del sitio los tres cerros 1 (Delta Superior del Paraná, departamento Victoria, Entre Ríos)

    OpenAIRE

    Di Prado, Violeta; Castro, Canela; Prieto, Nelly H.

    2013-01-01

    En esta contribución se presentan los primeros resultados del proyecto de colaboración interdisciplinaria “Estrategias de conservación y técnicas arqueométricas aplicadas sobre el registro cerámico del sitio arqueológico Los Tres Cerros 1 (Delta Superior del Paraná, Departamento Victoria, Entre Ríos)” (CETMIC/ FCNyM, UNLP). El conjunto abordado comprende más de 50.000 piezas e incluye fragmentos de cuencos y ollas, apéndices zoomorfos, masas de arcilla con improntas de dedos, entre otros. La ...

  10. Hydrothermal synthesis of magnetic reduced graphene oxide sheets

    International Nuclear Information System (INIS)

    Graphical abstract: An environmental friendly and efficient route for preparation of magnetic reduced graphene oxide composite with a one-step hydrothermal method was demonstrated. The reducing process was accompanied by generation of magnetic nanoparticles. Highlights: → A one-step hydrothermal method for preparation of MN-CCG was demonstrated. → Glucose was used as the 'green' reducing agent. → The reducing process was accompanied by generation of magnetic nanoparticles. → The prepared MN-CCG is highly water suspendable and sensitive to magnetic field. -- Abstract: We demonstrated an environmental friendly and efficient route for preparation of magnetic reduced graphene oxide composite (MN-CCG). Glucose was used as the reducing agent in this one-step hydrothermal method. The reducing process was accompanied by generation of magnetic nanoparticles. The structure and composition of the nanocomposite was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, thermal gravimetric analysis, atomic force microscopy and transmission electron microscopy. It was found that the prepared MN-CCG is highly water suspendable and sensitive to magnetic field.

  11. Agro-industrial waste to solid biofuel through hydrothermal carbonization.

    Science.gov (United States)

    Basso, Daniele; Patuzzi, Francesco; Castello, Daniele; Baratieri, Marco; Rada, Elena Cristina; Weiss-Hortala, Elsa; Fiori, Luca

    2016-01-01

    In this paper, the use of grape marc for energy purposes was investigated. Grape marc is a residual lignocellulosic by-product from the winery industry, which is present in every world region where vine-making is addressed. Among the others, hydrothermal carbonization was chosen as a promising alternative thermochemical process, suitable for the treatment of this high moisture substrate. Through a 50 mL experimental apparatus, hydrothermal carbonization tests were performed at several temperatures (namely: 180, 220 and 250 °C) and residence times (1, 3, 8 h). Analyses on both the solid and the gaseous phases obtained downstream of the process were performed. In particular, solid and gas yields versus the process operational conditions were studied and the obtained hydrochar was evaluated in terms of calorific value, elemental analysis, and thermal stability. Data testify that hydrochar form grape marc presents interesting values of HHV (in the range 19.8-24.1 MJ/kg) and physical-chemical characteristics which make hydrochar exploitable as a solid biofuel. In the meanwhile, the amount of gases produced is very small, if compared to other thermochemical processes. This represents an interesting result when considering environmental issues. Statistical analysis of data allows to affirm that, in the chosen range of operational conditions, the process is influenced more by temperature than residence time. These preliminary results support the option of upgrading grape marc toward its energetic valorisation through hydrothermal carbonization. PMID:26031328

  12. Hydrothermal processing of Hanford tank wastes: Process modeling and control

    International Nuclear Information System (INIS)

    In the Los Alamos National Laboratory (LANL) hydrothermal process, waste streams are first pressurized and heated as they pass through a continuous flow tubular reactor vessel. The waste is maintained at reaction temperature of 300--550 C where organic destruction and sludge reformation occur. This report documents LANL activities in process modeling and control undertaken in FY94 to support hydrothermal process development. Key issues discussed include non-ideal flow patterns (e.g. axial dispersion) and their effect on reactor performance, the use and interpretation of inert tracer experiments, and the use of computational fluid mechanics to evaluate novel hydrothermal reactor designs. In addition, the effects of axial dispersion (and simplifications to rate expressions) on the estimated kinetic parameters are explored by non-linear regression to experimental data. Safety-related calculations are reported which estimate the explosion limits of effluent gases and the fate of hydrogen as it passes through the reactor. Development and numerical solution of a generalized one-dimensional mathematical model is also summarized. The difficulties encountered in using commercially available software to correlate the behavior of high temperature, high pressure aqueous electrolyte mixtures are summarized. Finally, details of the control system and experiments conducted to empirically determine the system response are reported

  13. Controlling the visible luminescence in hydrothermal ZnO

    International Nuclear Information System (INIS)

    Cathodoluminescence spectra have been measured in hydrothermal and hydrogen-doped ZnO at different excitation densities and temperatures to investigate the emission efficiencies of near-band-edge (NBE), green and yellow luminescence bands. The NBE intensity depends linearly on the electron beam excitation as expected for excitonic recombination character. The intensities of the green and yellow bands are highly dependent not only on the excitation density but also on temperature. At high excitation densities ZnO exhibits dominant green emission at room temperature; the intensity of the green band can be further controlled by doping ZnO with hydrogen, which passivates green luminescence centers. Conversely at small excitation densities (< 0.1 nA) and low temperatures the visible luminescence from ZnO is predominantly yellow due to the abundance of Li in hydrothermal ZnO. The results are explained by differences in the recombination kinetics and the relative concentrations of the green and yellow centers, and illustrate that single-color emission can be achieved in ZnO by adjusting the excitation power and temperature. - Highlights: • Hydrothermal ZnO crystals are analyzed by cathodoluminescence spectroscopy. • Intensities of luminescence bands are highly dependent on excitation density. • Visible luminescence is influenced by temperature and hydrogen dopants. • Emission efficiencies are explained by recombination kinetics of defects

  14. Hydrothermal Oxidative Degradation of Organic Compounds Derived From Produced Water

    International Nuclear Information System (INIS)

    Produced water contains various hazardous organic compounds such as BTEX (benzene, toluene, ethyl benzene and xylene), phenolics and polycyclic aromatic hydrocarbons (PAHs). These compounds are stable and difficult to degrade by conventional wastewater treatment method. Aqueous based hydrothermal oxidative method is viewed as a promising approach for produced water treatment. The experiment was conducted in a micro-bomb reactor at subcritical water condition (200-300 degree Celsius) and 30 minute reaction time. Hydrogen peroxide was used as an oxidant. The reaction products were analyzed using a Fourier Transform Infra-Red (FTIR) and a Gas Chromatography-Mass Spectroscopy (GC-MS). The hydrothermal treatment in the absence of an oxidant showed minimal degradation of organics for the temperature range investigated. With the presence of an oxidant, the organics degradation increased drastically to near completion within the 30 minute reaction time at 300 degree Celsius. The results indicated that most of the organic compounds found in the produced water were successfully degraded using hydrothermal oxidative method. (author)

  15. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases

    Science.gov (United States)

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K. G.

    2016-04-01

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007) Proc Natl Acad Sci USA 104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ˜85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of 10-310-3 wt % that is typical for concentrations in shallow lakes on early Earth.

  16. Hydrothermal synthesis of magnetite particles with uncommon crystal facets

    Directory of Open Access Journals (Sweden)

    Junki Sato

    2014-09-01

    Full Text Available Hydrothermal synthesis of Fe3O4 (magnetite particles was carried out using organic compounds as morphology control agents to obtain magnetite crystals with uncommon facets. It was established that the morphology of Fe3O4 crystals obtained by hydrothermal treatment of an aqueous solution containing Fe2+ and organic compounds depended on the organic compound used. The shape of the Fe3O4 particles obtained when no additives were used was quasi-octahedral. In contrast, the addition of picolinic acid, citric acid or pyridine resulted in the formation of polyhedral crystals, indicating the presence of not only {1 1 1}, {1 0 0} and {1 1 0} facets but also high-index facets including at least {3 1 1} and {3 3 1}. When citric acid was used as an additive, octahedral crystals with {1 1 1} facets also appeared, and their size decreased as the amount of citric acid was increased. Thus, control of Fe3O4 particle morphology was achieved by a simple hydrothermal treatment using additives.

  17. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases.

    Science.gov (United States)

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K G; Wiegand, Simone

    2016-04-19

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007)Proc Natl Acad Sci USA104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of[Formula: see text]wt % that is typical for concentrations in shallow lakes on early Earth. PMID:27044100

  18. Lithium isotope traces magmatic fluid in a seafloor hydrothermal system

    Science.gov (United States)

    Yang, Dan; Hou, Zengqian; Zhao, Yue; Hou, Kejun; Yang, Zhiming; Tian, Shihong; Fu, Qiang

    2015-09-01

    Lithium isotopic compositions of fluid inclusions and hosted gangue quartz from a giant volcanogenic massive sulfide deposit in China provide robust evidence for inputting of magmatic fluids into a Triassic submarine hydrothermal system. The δ7Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions). These data confirm the temperature-dependent Li isotopic fractionation between hydrothermal quartz and fluid (i.e., Δδ7Liquartz-fluid = -8.9382 × (1000/T) + 22.22(R2 = 0.98 175 °C-340 °C)), which suggests that the fluid inclusions are in equilibrium with their hosted quartz, thus allowing to determine the composition of the fluids by using δ7Liquartz data. Accordingly, we estimate that the ore-forming fluids have a δ7Li range from -0.7‰ to +18.4‰ at temperatures of 175-340 °C. This δ7Li range, together with Li-O modeling , suggest that magmatic fluid played a significant role in the ore formation. This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process.

  19. Polymer-Assisted Hydrothermal Synthesis of Hierarchically Arranged Hydroxyapatite Nanoceramic

    Directory of Open Access Journals (Sweden)

    A. Joseph Nathanael

    2013-01-01

    Full Text Available Flower-like hydroxyapatite (HA nanostructures were synthesized by a polymer-assisted hydrothermal method. The thickness of the petals/plates decreased from 200 nm to 40 nm as the polymer concentration increased. The thickness also decreased as the hydrothermal treatment time increased from 6 to 12 hr. The HRTEM and SAED patterns suggest that the floral-like HA nanostructures are single crystalline in nature. Structural analysis based on XRD and Raman experiments implied that the produced nanostructure is a pure form of HA without any other impurities. The possible formation mechanism was discussed for the formation of flower-like HA nanostructures during polymer-assisted hydrothermal synthesis. Finally, in vitro cellular analysis revealed that the hierarchically arranged HA nanoceramic had improved cell viability relative to other structures. The cells were actively proliferated over these nanostructures due to lower cytotoxicity. Overall, the size and the crystallinity of the nanostructures played a role in improving the cell proliferation.

  20. DESIGN OF NOVEL HIGH PRESSURE- RESISTANT HYDROTHERMAL FLUID SAMPLE VALVE

    Institute of Scientific and Technical Information of China (English)

    LIU Wei; YANG Canjun; WU Shijun; XIE Yingjun; CHEN Ying

    2008-01-01

    Sampling study is an effective exploration method, but the most extreme environments of hydrothermal vents pose considerable engineering challenges for sampling hydrothermal fluids. Moreover, traditional sampler systems with sample valves have difficulty in maintaining samples in situ pressure. However, decompression changes have effect on microorganisms sensitive to such stresses. To address the technical difficulty of collecting samples from hydrothermal vents, a new bidirectional high pressure-resistant sample valve with balanced poppet was designed. The sample valve utilizes a soft high performance plastic "PEEK" as poppet. The poppet with inapposite dimension is prone to occur to plastic deformation or rupture for high working pressure in experiments. To address this issue, based on the finite element model, simulated results on stress distribution of the poppet with different structure parameters and preload spring force were obtained. The static axial deformations on top of the poppet were experimented. The simulated results agree with the experimental results. The new sample valve seals well and it can withstand high working pressure.

  1. Hydrothermal treatment and ethanol pulping of sunflower stalks.

    Science.gov (United States)

    Caparrós, S; Ariza, J; López, F; Nacimiento, J A; Garrote, G; Jiménez, L

    2008-03-01

    The influence of temperature in the hydrothermal treatment of sunflower stalks on the composition of the liquid fraction obtained was examined. The remaining solid fraction was subjected to ethanol pulping in order to obtain pulp that was used to produce paper sheets. The pulp was characterized in terms of yield, kappa index, viscosity, and cellulose, hemicellulose and lignin contents; and the paper sheets in terms of breaking length, stretch, burst index and tear index. Hydrothermal treatment of the raw material at 190 degrees C provided a liquid phase with maximal hemicellulose-derived oligomers and monosaccharide (glucose, xylose and arabinose) contents (26.9 and 4.2 g/L, respectively). Pulping the solid fraction obtained by hydrothermal treatment at 180 degrees C, with 70% ethanol at a liquid/solid ratio of 8:1 at 170 degrees C for 120 min provided pulp with properties on a par with those of soda pulp from the sunflower stalks, namely: 36.3% yield, 69.1% cellulose, 12.6% hemicellulose, 18.2% lignin and 551 ml/g viscosity. Also, paper sheets obtained from the ethanol pulp were similar in breaking length (3.8 km), stretch (1.23%), burst index (1.15 kN/g) and tear index (2.04 m Nm(2)/g) to those provided by soda pulp. PMID:17369038

  2. Preparation of highly active and hydrothermally stable nickel catalysts.

    Science.gov (United States)

    Li, Shaozhong; Chen, Hui; Shen, Jianyi

    2015-06-01

    The 60%Ni/AlSiO catalysts were prepared by the co-precipitation method, in which AlSiO were the composite supports with different mass ratios of Al2O3 and SiO2. It was found that the catalyst 60%Ni/AlSiO-4 with the Al2O3/SiO2 mass ratio of 4 in the support exhibited the high hydrothermal stability. The addition of proper amount of SiO2 inhibited the hydration of Al2O3 and prevented the growth of supported nickel particles during the hydrothermal treatment. The structure of the composite support in the 60%Ni/AlSiO-4 was stable and the supported nickel particles were highly dispersed. Accordingly, the hydrothermally treated catalyst maintained the high heats and uptakes for the adsorption of H2 and CO, and thus the high activity and stability for the hydrogenation of glucose to sorbitol in aqueous solution. PMID:25700212

  3. Nuevos datos, viejas colecciones: los conjuntos óseos de Cerro Casa de Piedra Cueva 5 (Parque Nacional Perito Moreno, Santa Cruz New data, old collections: Cerro Casa de Piedra 5 bone assemblages (Perito Moreno National Park, Santa Cruz Province, Argentina

    Directory of Open Access Journals (Sweden)

    Mariana E. De Nigris

    2007-12-01

    Full Text Available En este trabajo se presentan los resultados de un nuevo análisis de las colecciones óseas de Cerro Casa de Piedra Cueva 5, emplazado en el Parque Nacional Perito Moreno, provincia de Santa Cruz. Las muestras óseas fueron recuperadas en excavaciones sistemáticas realizadas en la década del ´80 y se ubican temporalmente en el Holoceno medio y tardío (ca. 2500-6500 años. El principal objetivo de este estudio es identificar las posibles variaciones existentes en el aprovechamiento de los recursos faunísticos con el fin de alcanzar un mayor entendimiento de las estrategias que implementaron las sociedades cazadoras recolectoras en torno a la utilización de los recursos de origen animal. Los resultados señalan al guanaco (Lama guanicoe como la especie dominante si bien el huemul (Hippocamelus bisulcus forma parte importante de la dieta. En ambos ungulados se observa un predominio del esqueleto apendicular por sobre el axial y una gran diversidad de marcas de procesamiento compatibles con situaciones de consumo. Sin embargo, a pesar de estas regularidades se han registrado también diferencias en el aprovechamiento de las presas a través del tiempo.This paper presents the results of a new analysis of bone collections from Cerro Casa de Piedra Cueva 5. The archaeological site is a large cave positioned on the north side of a volcanic hill located on the southern bank of Roble river (900 masl in a transitional area between the forest and the shrubby Patagonian steppe within the Perito Moreno National Park, northwest of Santa Cruz, Argentina. The occupational sequence is formed by four stratigraphic layers radiocarbon dated between ca. 2500 and 6500 years BP. Bone samples had been recovered during the 1980s but have received no attention since. The main aim of this paper is to identify continuities and changes in faunal resource consumption to better understand hunter-gatherer strategies during the Middle and Late Holocene. The analyzed

  4. Geochronology of TAG and Snakepit hydrothermal fields, Mid-Atlantic Ridge: Witness to a long and complex hydrothermal history

    International Nuclear Information System (INIS)

    Geochronological studies of a large number of precipitates from the TAG hydrothermal field and of few samples from Snakepit hydrothermal field of the Mid-Atlantic Ridge show intermittent repeated hydrothermal events at both sites. 210Pb/Pb and 230Th/234U measurements of sulfides, iron and manganese oxides, and 14C measurements of carbonates combined with observations of hydrothermal events recorded as discrete layers in sediment cores provide the basis for unravelling the temporal history of the fields. The TAG field shows intermittent activity over the past 120,000 years as evidenced by ages of low-temperature Mn oxides. The presently active black smoker mound first formed about 40,000-50,000 years ago with precipitation of massive sulfides. It has had intermittent, pulsed high-temperature activity every 5000-6000 years over the past 20,000 years which may reflect renewed magmatic actvity at the ridge axis. Fluid flow is focussed at the mound site by structural and tectonic control suggested by the intersection of N-S ridge parallel lystric normal faults and an E-W transform fault. Periods of inactivity are marked by covering of the mound with pelagic carbonate ooze which is probably partially dissolved and reprecipiated as aragonite at the end of each high-temperature event. The Snakepit field had an initial event about 4000 years ago, probably shortly after the eruption of the volcanic ridge on which it sits. A recent renewal, still presently active, was probably initiated by recent fissuring of the volcanic pile. (orig.)

  5. Hydrothermal treatment of titanium alloys for the enhancement of osteoconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Zuldesmi, Mansjur, E-mail: mzuldesmi@yahoo.com [Department of Materials Science & Engineering, Graduate School of Engineering, Nagoya University, Nagoya (Japan); Department of Mechanical Engineering, Manad State University (UNIMA) (Indonesia); Waki, Atsushi [Department of Materials Science & Engineering, Graduate School of Engineering, Nagoya University, Nagoya (Japan); Kuroda, Kensuke; Okido, Masazumi [EcoTopia Science Institute, Nagoya University, Nagoya (Japan)

    2015-04-01

    The surface wettability of implants is a crucial factor in their osteoconductivity because it influences the adsorption of cell-attached proteins onto the surface. In this study, a single-step hydrothermal surface treatment using distilled water at a temperature of 180 °C for 3 h was applied to titanium (Ti) and its alloys (Ti–6Al–4V, Ti–6Al–7Nb, Ti–29Nb–13Ta–4.6Zr, Ti–13Cr–1Fe–3Al; mass%) and compared with as-polished Ti implants and with implants produced by anodizing Ti in 0.1 M of H{sub 3}PO{sub 4} with applied voltages from 0 V to 150 V at a scanning rate of 0.1 V s{sup −1}. The surface-treated samples were stored in a five time phosphate buffered saline (× 5 PBS(−)) solution to prevent increasing the water contact angle (WCA) with time. The surface characteristics were evaluated using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, surface roughness, and contact angle measurement using a 2 μL droplet of distilled water. The relationship between WCA and osteoconductivity at various surface modifications was examined using in vivo tests. The results showed that a superhydrophilic surface with a WCA ≤ 10° and a high osteoconductivity (R{sub B–I}) of up to 50% in the cortical bone part, about four times higher than the as-polished Ti and Ti alloys, were provided by the combination of the hydrothermal surface treatment and storage in × 5 of PBS(−). - Highlights: • Hydrothermal treatment in distilled water was applied to titanium alloys. • Surface characteristics and osteoconductivity by in vivo test were evaluated. • Water contact angles of titanium alloys were decreased by hydrothermal treatment. • Osteoconductivity of titanium alloys improved notably by hydrothermal treatment after stored in × 5 of PBS (−)

  6. Hydrothermal conversion of chrysotile asbestos using near supercritical conditions

    International Nuclear Information System (INIS)

    The present research investigates, develops and evaluates the transformation of chrysotile asbestos into a non-hazardous material, such as forsterite, using an economically viable and safe method. The aim of this study is to convert fibrous chrysotile asbestos into an anhydrous magnesium silicate with a non-hazardous lamellar morphology using supercritical steam. The treatment method is characterized as hydrothermal in a temperature and pressure range of 300-700 deg. C and 1.75-5.80 MPa, respectively. Small amounts of asbestos (2.5 g) were treated in each experiment. Deionised water was used as the treatment solution. The treatment duration varied from approximately 1-5 h. Additional experiments took place using solutions of distilled water and small amounts of acetic acid, with the aim of attaining optimal treatment conditions. Crystal phases of the samples were determined by X-ray diffraction (XRD). The main phases present in the treated samples were forsterite, enstatite, and chrysotile asbestos. Lizardite and periclase were also found. The morphology of the treated chrysotile asbestos fibers was identified by scanning electron microscope (SEM). The fibrous form of chrysotile asbestos was converted into non-fibrous form of forsterite. In fact, none of the fibrous-needle-like morphology, with length equal to or greater than 5 μm and diameter less than 3 μm, which was responsible for the toxicity of the original material, was visible in the solid phase. The dissolution of magnesium from chrysotile asbestos was measured using volumetric determination by titration with EDTA. Leaching of magnesium into the liquid phase was observed. Clearly, the highest concentrations of dissolved magnesium are observed after hydrothermal treatment of chrysotile asbestos using acetic acid 1% (8.4-14.6%). Lowest concentrations of dissolved magnesium are obtained after hydrothermal treatment of chrysotile asbestos without using additives. Observing the results of the hydrothermal

  7. Hydrothermal circulation within the Endeavour Segment, Juan de Fuca Ridge

    Science.gov (United States)

    Johnson, H. Paul; Tivey, Maurice A.; Bjorklund, Tor A.; Salmi, Marie S.

    2010-05-01

    Areas of the seafloor at mid-ocean ridges where hydrothermal vents discharge are easily recognized by the dramatic biological, physical, and chemical processes that characterize such sites. Locations where seawater flows into the seafloor to recharge hydrothermal cells within the crustal reservoir are by contrast almost invisible but can be indirectly identified by a systematic grid of conductive heat flow measurements. An array of conductive heat flow stations in the Endeavour axial valley of the Juan de Fuca Ridge has identified recharge zones that appear to represent a nested system of fluid circulation paths. At the scale of an axial rift valley, conductive heat flow data indicate a general cross-valley fluid flow, where seawater enters the shallow subsurface crustal reservoir at the eastern wall of the Endeavour axial valley and undergoes a kilometer of horizontal transit beneath the valley floor, finally exiting as warm hydrothermal fluid discharge on the western valley bounding wall. Recharge zones also have been identified as located within an annular ring of very cold seafloor around the large Main Endeavour Hydrothermal Field, with seawater inflow occurring within faults that surround the fluid discharge sites. These conductive heat flow data are consistent with previous models where high-temperature fluid circulation cells beneath large hydrothermal vent fields may be composed of narrow vertical cylinders. Subsurface fluid circulation on the Endeavour Segment occurs at various crustal depths in three distinct modes: (1) general east to west flow across the entire valley floor, (2) in narrow cylinders that penetrate deeply to high-temperature heat sources, and (3) supplying low-temperature diffuse vents where seawater is entrained into the shallow uppermost crust by the adjacent high-temperature cylindrical systems. The systematic array of conductive heat flow measurements over the axial valley floor averaged ˜150 mW/m2, suggesting that only about 3% of

  8. La avalancha de rocas del cerro Los Cardos (37°10´S,70°53´O) en la región norte de la provincia del Neuquén The rock avalanche of Cerro Los Cardos (37° 10´S, 70° 53´ W) in the northern region of the province of Neuquén

    OpenAIRE

    E.F. González Díaz; Folguera, A.; Hermanns, R.

    2005-01-01

    Se describe una nueva e importante avalancha de rocas, no reconocida hasta ahora, localizada a unos 25 km al oeste de la población de Andacollo. Muestra dos cicatrices o muescas de desprendimiento, de las cuales la austral es interpretada como la muesca principal de su desprendimiento y se halla al pie del borde occidental de una planicie estructural lávica, sobre cuyo extremo norte se ubica el cerro Los Cardos. Es un complejo movimiento, con numerosas escarpas de arranque internas en la masa...

  9. Formation de caldera par fluage d'un système hydrothermal volcanique

    OpenAIRE

    Barde-Cabusson, Stéphanie

    2007-01-01

    The influence of a hydrothermal system within a volcanic edifice has been poorly studied with respect to volcano instability. This study deals with the relation between hydrothermal systems and tectonics, through the analysis of the deformations triggered in a volcanic cone by the flow of hydrothermally altered rocks. The presence of these clays, ductile at geological time scale, deeply changes the behaviour and the evolution of a volcanic edifice, which may lead to the formation of huge coll...

  10. Energy Transfer Through Food Webs at Hydrothermal Vents: Linking the Lithosphere to the Biosphere

    OpenAIRE

    Breea Govenar

    2012-01-01

    Tectonic and volcanic processes that drive hydrothermal fluid flow and influence its chemistry also regulate the transfer of energy to hydrothermal vent ecosystems. Chemoautotrophic bacteria use the chemical energy generated by mixing the reduced chemicals in hydrothermal fluids with deep-ocean ambient seawater to fix inorganic carbon and produce biomass. These and other microbes, or their products, are then consumed by other organisms, which are subsequently consumed by other organisms. The ...

  11. Dike-Driven Hydrothermal Processes on Mars and Sill Emplacement on Europa

    OpenAIRE

    Craft, Kathleen Liana

    2013-01-01

    Evidence of hydrothermal and tectonic activity is found throughout our solar system. Here I investigated hydrothermal and fracturing processes on three planetary bodies: Earth, Mars and Europa. For the first project, we set up a dike-driven hydrothermal system and calculated heat and water flow using boundary layer theory. Water flow rates and volumes were then compared to the requirements for surface feature formation. Results found that the water volumes produced were adequate to form At...

  12. Influence of Hydrothermal Temperature on Phosphorus Recovery Efficiency of Porous Calcium Silicate Hydrate

    OpenAIRE

    Wei Guan; Fangying Ji; Qingkong Chen; Peng Yan; Weiwei Zhou

    2013-01-01

    Porous calcium silicate hydrate (PCSH) was synthesized by carbide residue and white carbon black. The influence of hydrothermal temperature on phosphorus recovery efficiency was investigated by Field Emission Scanning Electron Microscopy (FESEM), Brunauer-Emmett-Teller (BET), and X-Ray Diffraction (XRD). Hydrothermal temperature exerted significant influence on phosphorus recovery performance of PCSH. Hydrothermal temperature 170°C for PCSH was more proper to recover phosphorus. PCSH could re...

  13. Using micro-scale evidence to understand regional-scale hydrothermal alteration of plutonic rocks

    OpenAIRE

    Plümper, O.; King, H. E.; Putnis, A.

    2009-01-01

    Subsolidus re-equilibration of plutonic feldspars induced by hydrothermal fluids provides a valuable record of fluid-rock interactions that affect large volumes of the Earth's continental crust (Taylor, 1977). The effect of hydrothermal fluids has important implications for the interpretation of the present plutonic mineralogy and geochemistry. However, crustal hydrothermal activity is usually not accounted for unless stages of replacement can be identified or new minerals that are characteri...

  14. Hydrothermal alteration of the ocean crust: insights from Macquarie Island and drilled in situ ocean crust

    OpenAIRE

    Coggon, Rosalind Mary

    2006-01-01

    Hydrothermal circulation is a fundamental process in the formation and aging of the ocean crust, influencing its structure, physical and chemical properties, and the composition of the oceans and the mantle. The impact of hydrothermal circulation on mid-ocean ridge processes depends on the composition and volume of circulating hydrothermal fluids, and the extent of partitioning between high temperature axial- and low temperature ridge flank- systems, but these processes remain ...

  15. Molecular Ecology of Free-Living Chemoautotrophic Microbial Communities at a Shallow-sea Hydrothermal Vent

    OpenAIRE

    Huang, Chia-I

    2012-01-01

    Deep-sea hydrothermal systems are unique habitats for microbial life with primary production based on chemosynthesis. They are considered to be windows to the subsurface biosphere. Their far more accessible shallow-sea counterparts are valuable targets to study the effects of hydrothermal activity on geology, seawater chemistry and microorganisms. Such an area of shallow-sea hydrothermal venting is observed approximately 2.5 km east off Panarea Island (Sicily, Italy). This system is character...

  16. Catalytic Hydrothermal Conversion of Wet Biomass Feedstocks and Upgrading – Process Design and Optimization

    DEFF Research Database (Denmark)

    Hoffmann, Jessica; Toor, Saqib; Rosendahl, Lasse

    Liquid biofuels will play a major role for a more sustainable energy system of the future. The CatLiq® process is a 2nd generation biomass conversion process that is based on hydrothermal liquefaction. Hydrothermal liquefaction offers a very efficient and feedstock flexible way of converting...... biomass to bio-oil. Bio-oils from hydrothermal liquefaction are characterised by their high feedstock flexibility. Upgrading of complete bio-oils derived from hydrothermal conversion has not yet been extensively studied. Purpose of this work is to reduce the oxygen content of the bio-oil to improve the...

  17. Spatial distribution of viruses associated with planktonic and attached microbial communities in hydrothermal environments.

    Science.gov (United States)

    Yoshida-Takashima, Yukari; Nunoura, Takuro; Kazama, Hiromi; Noguchi, Takuroh; Inoue, Kazuhiro; Akashi, Hironori; Yamanaka, Toshiro; Toki, Tomohiro; Yamamoto, Masahiro; Furushima, Yasuo; Ueno, Yuichiro; Yamamoto, Hiroyuki; Takai, Ken

    2012-03-01

    Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments. PMID:22210205

  18. A high-temperature hydrothermal deposit on the East Pacific Rise near 70N

    International Nuclear Information System (INIS)

    A SEABEAM survey of the East Pacific Rise (EPR) led to the selection of several sites having structural characteristics favorable for hydrothermal activity. Dredging of such an area located at 70 N on the EPR resulted in the recovery of sulfides, oxides and fresh basalt. Chemical analyses and isotopic compositions showed that the recovered pyrites were probably precipitated directly from hot vent hydrothermal waters. Chemical analyses and isotopic composition of manganese-iron oxides indicated that they too were of hydrothermal origin. 210Pb/Pb measurements yielded ages of 90 +- 10 years for the deposits. This site may still be undergoing hydrothermal activity. (orig.)

  19. Hydrothermal Vents at 5000m on the Mid-Cayman Rise: The Deepest and Hottest Hydrothermal Systems Yet Discovered!

    Science.gov (United States)

    Murton, B. J.; Connelly, D. P.; Copley, J. T.; Stansfield, K. L.; Tyler, P. A.; Cruise Jc044 Sceintific Party

    2010-12-01

    This contribution describes the geological setting of hydrothermal activity within the Mid- Cayman Rise (MCR) using data acquired during cruise JC044 (MAR-APR 2010) from the deep-towed sidescan sonar TOBI, AUV Autosub6000 and the ROTV HyBIS. The 110 km-long Mid- Cayman Rise (MCR), located within Caribbean Sea, is the deepest spreading centre known, reaching over 6000m. Hence it poses an end-member of extreme depth for hydrothermal circulation. Accretion of new volcanic crust is focused within two ridge segments, to the north and south of a centrally located massif of peridotite and gabbro. Following earlier indications of hydrothermal plumes (German et al., in 2009), we discovered two high-temperature hydrothermal system: one at a depth of 5000m in the neovolcanic zone of the northern segment, and another at 2300m on the flanks of the MCR. These sites show contrasting styles of fluid venting, mineralisation, geological setting and host rock interaction. At 5000m-depth, the ultra-deep vent site forms the deepest hydrothermal system known. Venting is focused at the western side of a 100m diameter, 30m high mound, while inactive sulphides extend eastwards for at least 800m. Fluids discharge from clusters of chimneys whose location is related to basement faults. Changes in salinity in the venting fluids indicate discharge of a low salinity phase and a brine phase. At 500bar, this is definitive evidence for supercritical fluid emission. We also found the sulphide mineralization to be copper-rich, giving a characteristic green hue to many of the deposits, probably a result of the super-critical state of the vent fluids. A prominent axial volcanic ridge nearby indicates a robust magma supply to the northern MCR segment. Thus it is likely the ultra-deep vent site derives its thermal energy from magmatic sources, similar to those thought to underlie other slow-spreading ridge volcanic-hosted vent sites (e.g. Broken Spur: MAR). The shallower (2300m) MCR hydrothermal vent

  20. Crystallization conditions and petrogenesis of the lava dome from the ˜900 years BP eruption of Cerro Machín Volcano, Colombia

    Science.gov (United States)

    Laeger, Kathrin; Halama, Ralf; Hansteen, Thor; Savov, Ivan P.; Murcia, Hugo F.; Cortés, Gloria P.; Garbe-Schönberg, Dieter

    2013-12-01

    The last known eruption at Cerro Machín Volcano (CMV) in the Central Cordillera of Colombia occurred ˜900 years BP and ended with the formation of a dacitic lava dome. The dome rocks contain both normally and reversely zoned plagioclase (An24-54), unzoned and reversely zoned amphiboles of dominantly tschermakite and pargasite/magnesio-hastingsite composition and olivine xenocrysts (Fo = 85-88) with amphibole/clinopyroxene overgrowth, all suggesting interaction with mafic magma at depth. Plagioclase additionally exhibits complex oscillatory zoning patterns reflecting repeated replenishment, fractionation and changes in intrinsic conditions in the magma reservoir. Unzoned amphiboles and cores of the reversely zoned amphiboles give identical crystallization conditions of 910 ± 30 °C and 360 ± 70 MPa, corresponding to a depth of about 13 ± 2 km, at moderately oxidized conditions (f = +0.5 ± 0.2 ΔNNO). The water content in the melt, calculated based on amphibole chemistry, is 7.1 ± 0.4 wt.%. Rims of the reversely zoned amphiboles are relatively enriched in MgO and yield higher crystallization temperatures (T = 970 ± 25 °C), slightly lower melt H2O contents (6.1 ± 0.7 wt.%) and overlapping pressures (410 ± 100 MPa). We suggest that these rims crystallized following an influx of mafic melt into a resident magma reservoir at mid-crustal depths, further supported by the occurrence of xenocrystic olivine. Crystallization of biotite, albite-rich plagioclase and quartz occurred at comparatively low temperatures (probably <800 °C) during early stages of ascent or storage at shallower levels. Based on amphibole mineral chemistry, the felsic resident melt had a rhyolitic composition (71 ± 2 wt.% SiO2), whereas the hybrid magma, from which the amphibole rims crystallized, was dacitic (64 ± 3 wt.% SiO2). The bulk rock chemistry of the CMV lava dome dacites is homogenous. They have elevated (La/Nb)N ratios of 3.8-4.5, typical for convergent margin magmas, and display

  1. High-resolution mass spectrometric analysis of a vanadyl porphyrin fraction isolated from the {gt}700{degree}C resid of Cerro Negro heavy petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Grigsby, R.D.; Green, J.B. [National Institute for Petroleum and Energy Research, Bartlesville, OK (United States). BDM-Oklahoma, Inc.

    1997-05-01

    A vanadium-enriched fraction from the {gt}700{degree}C resid of Cerro Negro heavy petroleum was analyzed by high-resolution, low-energy, electron-ionization mass spectrometry (low eV HR/MS). This fraction was known to contain 4.6 wt% of the total vanadium in the whole resid. On the basis of UV-visible absorption spectra, the concentration of porphyrinic vanadium in the fraction was previously estimated to be 56.4 wt% of the total vanadium. Because the porphyritic vanadium accounted for only about one-half of the total, an independent method was needed to characterize the nonporphyrinic vanadium in the fraction. Low-eV HR/MS with sample introduction by probe microdistillation was selected. Etioporphyrins (C{sub n}H{sub 2n-2}N{sub 4}VO) with molecular weights ranging from 487 to 879 were found to be the most abundant vanadium-containing compounds in the fraction. Deoxophylloerythroetio-porphyrins (C{sub n}H{sub 2n-30}N{sub 4}VO) with molecular weights ranging from 499 to 863 were the second most abundant. In addition, other compound types have the formula C{sub n}H{sub 2n+z}N{sub 4}VO, where z ranges from -32 to -50, excluding -46, were found. Additional saturated and aromatic rings present in compounds with more negative z numbers would appreciably alter their UV-visible absorption spectra relative to those of etioporphyrins. That is, the response of the other porphyrin types would be lower than that of etioporphyrins at 570 nm, the wavelength used for the determination of vanadyl porphyrin. Thus, the broad distribution of vanadyl porphyrin types identified in the fraction by low-eV HR/MS strongly suggests that at least a part of the apparent nonporphyrinic vanadium thought to be present in the fraction is, in fact, porphyrinic and is explained by the use of molar absorptivities based solely on those of etioporphyrins to calculate total porphyrin content. 48 refs., 7 figs., 2 tabs.

  2. In situ chemical sensing for hydrothermal plume mapping and modeling

    Science.gov (United States)

    Fukuba, T.; Kusunoki, T.; Maeda, Y.; Shitashima, K.; Kyo, M.; Fujii, T.; Noguchi, T.; Sunamura, M.

    2012-12-01

    Detection, monitoring, and mapping of biogeochemical anomalies in seawater such as temperature, salinity, turbidity, oxidation-reduction potential, and pH are essential missions to explore undiscovered hydrothermal sites and to understand distribution and behavior of hydrothermal plumes. Utilization of reliable and useful in situ sensors has been widely accepted as a promised approach to realize a spatiotemporally resolved mapping of anomalies without water sampling operations. Due to remarkable progresses of sensor technologies and its relatives, a number of highly miniaturized and robust chemical sensors have been proposed and developed. We have been developed, evaluated, and operated a compact ISFET (Ion-Sensitive Field-Effect Transistor)-based chemical sensors for ocean environmental sensing purposes. An ISFET has advantages against conventional glass-based electrodes on its faster response, robustness, and potential on miniaturization, and thus variety of chemical sensors has been already on the market. In this study, ISFET-based standalone pH sensors with a solid-state Cl-ISE as a reference electrode were mounted on various platforms and operated to monitor the pH anomalies in deep-sea environment at the Kairei, Edmond, and surrounding hydrothermal sites in the southern Central Indian Ridge area during KH10-06 scientific cruise (Nov. 2010), supported by project TAIGA (Trans-crustal Advection and In situ biogeochemical processes of Global sub-seafloor Aquifer). Up to three pH sensors were mounted on a wire-lined CTD/RMS (Rosette Multiple Sampler), dredge sampler, a series of MTD plankton nets, and VMPS (Vertical Multiple-operating Plankton Sampler). A standalone temperature sensor was bundled and operated with the pH sensor when they were mounted on the dredge sampler, MTD plankton nets, and VMPS. An AUV equipped with the pH sensor was also operated for hydrothermal activity survey operations. As a result of Tow-Yo intersect operations of the CTD

  3. Genome-resolved metagenomics reveals that sulfur metabolism dominates the microbial ecology of rising hydrothermal plumes

    Science.gov (United States)

    Anantharaman, K.; Breier, J. A., Jr.; Jain, S.; Reed, D. C.; Dick, G.

    2015-12-01

    Deep-sea hydrothermal plumes occur when hot fluids from hydrothermal vents replete with chemically reduced elements and compounds like sulfide, methane, hydrogen, ammonia, iron and manganese mix with cold, oxic seawater. Chemosynthetic microbes use these reduced chemicals to power primary production and are pervasive throughout the deep sea, even at sites far removed from hydrothermal vents. Although neutrally-buoyant hydrothermal plumes have been well-studied, rising hydrothermal plumes have received little attention even though they represent an important interface in the deep-sea where microbial metabolism and particle formation processes control the transformation of important elements and impact global biogeochemical cycles. In this study, we used genome-resolved metagenomic analyses and thermodynamic-bioenergetic modeling to study the microbial ecology of rising hydrothermal plumes at five different hydrothermal vents spanning a range of geochemical gradients at the Eastern Lau Spreading Center (ELSC) in the Western Pacific Ocean. Our analyses show that differences in the geochemistry of hydrothermal vents do not manifest in microbial diversity and community composition, both of which display only minor variance across ELSC hydrothermal plumes. Microbial metabolism is dominated by oxidation of reduced sulfur species and supports a diversity of bacteria, archaea and viruses that provide intriguing insights into metabolic plasticity and virus-mediated horizontal gene transfer in the microbial community. The manifestation of sulfur oxidation genes in hydrogen and methane oxidizing organisms hints at metabolic opportunism in deep-sea microbes that would enable them to respond to varying redox conditions in hydrothermal plumes. Finally, we infer that the abundance, diversity and metabolic versatility of microbes associated with sulfur oxidation impart functional redundancy that could allow it to persist in the dynamic settings of hydrothermal plumes.

  4. Structural Geometry of a Sector of the Colorado River Delta, Baja California, Mexico, Based on Seismic Reflections

    Science.gov (United States)

    Chanes-Martínez, J. Juan; González-Escobar, Mario; Suárez-Vidal, Francisco; Gallardo-Mata, Clemente G.

    2014-07-01

    A structural study in the SW section of the Colorado River delta using seismic reflection data is presented. The study area is located along the Cerro Prieto transform fault, which extends from the northern Gulf of California through the Mexicali Valley and is an active fault within the Pacific-North American plate boundary zone. The research was supported by a database of five seismic profiles with a total length of 215 km, collected in the early 80's by Petróleos Mexicanos. The results show a high density of faults, most of which are buried by sediments. Within the Cerro Prieto fault zone, several faults were identified, such as: Palmas, Mesa, and Pangas Viejas, until now unknown. In addition, even though the Indiviso fault was investigated and superficially identify prior to this work, herein mapped at depth. West of the Cerro Prieto fault zone lies the Las Tinajas basin, bound by the Dunas and Saldaña faults and by the Montague basin to the southeast. The deformation zone along the plate boundary is 18-km-wide, stretching from the Cerro Prieto fault in the east to the Pangas Viejas fault in the west. The orientations of the faults are NW-SE, and if projected from the southern side of the Sierra Cucapah southward, the faults tend to join the Cerro Prieto fault. In the Las Tinajas basin, the acoustic basement is deeper than 5,000 m. Some of the largest vertical displacements generated by the 2010 7.2-Mw El Mayor-Cucapah earthquake occurred southeast of the epicenter and coincided with the location of the Pangas Viejas Fault, which is buried by sediments. Before this event, seismic activity was very low, and no structures were known in the area. In this paper, we demonstrate that there are at least seven major faults that may now pose a high seismic hazard.

  5. Hydrothermal interactions of cement or mortar with zeolites or montmorillonites

    International Nuclear Information System (INIS)

    Concretes, grouts, clays and/or zeolites are candidate borehole, shaft or tunnel plugging materials for any nuclear waste repository. Interactions between these plugging materials may take place under mild hydrothermal conditions during the life of a repository. Class H cement or motar (PSU/WES mixture) was reacted with one of two montmorillonites, clinoptilolite or mordenite at 1000 and 2000C for different periods under a confining pressure of 30 MPa. The solid reaction products were characterized by x-ray powder diffraction and scanning electron microscopy after the hydrothermal treatments. When zeolites were in contact (not intimate mixture) with class H cement, they did not seem to alter but clinoptilolite altered to analcime, and mordenite became poorly crystalline in the presence of mortar (containing NaCl) at both 1000 and 2000C. When cement or mortar was intimately mixed with zeolites or montmorillonites and reacted hydrothermally, the reaction resulted in the formation of Al substituted tobermorite (11A type) in all cases (this type of reaction is expected at the interface) at both 1000 and 2000C. The mechanism of tobermorite formation includes the decomposition of zeolites or montmorillonites in the presence of alkaline (pH approx. = 12) cement or mortar and recrystallization to form Al substituted tobermorite. Cesium sorption measurements in 0.01N CaCl2 on the reaction products revealed that selective Cs sorption increased in most cases, even though little or none of the original zeolites and montmorillonites remained in the products. For example, Cs sorption K/sub d/ (mL/g) increased from 80 in the untreated mortar + Ca montmorillonite mixture to 1700 in the interaction product which is Al substituted tobermorite. Thus, we discover here that Al substituted tobermorite has good selectivity for Cs

  6. Discovery of new hydrothermal vent sites in Bransfield Strait, Antarctica

    Science.gov (United States)

    Klinkhammer, G. P.; Chin, C. S.; Keller, R. A.; Dählmann, A.; Sahling, H.; Sarthou, G.; Petersen, S.; Smith, F.; Wilson, C.

    2001-12-01

    We carried out a search for hydrothermal vents in the Central Basin of Bransfield Strait, Antarctica. The ZAPS (zero angle photon spectrometer) chemical sensor and instrument package (Oregon State University), OFOS (ocean-floor observation system) camera sled and TVG (TV-grab) (GEOMAR) were used to explore the water column and underlying seafloor. These operations were supplemented with a series of dredges. Hydrothermal plumes over Hook Ridge at the eastern end of the basin are confined to the E ridge crest and SE flank. The plumes are complex and sometimes contain two turbidity maxima one widespread feature centered at 1150 m and a smaller, more localized but broad maximum at 600-800 m. We traced the source of the shallower plume to a sunken crater near the ridge crest using sensors on the ZAPS instrument package. Subsequently two TV-grabs from the crater brought back hot, soupy sediment (42-49°C) overlain by hard, siliceous crusts and underlain by a thick layer of volcanic ash. We also recovered chimney fragments whose texture and mineralogy indicate venting temperatures in excess of 250°C. Native sulfur and Fe-sulfides occur in fractures and porous layers in sediment from throughout the area. Pore water data from the crater site are consistent with venting into a thin sediment layer and indicate phase separation of fluids beneath Hook Ridge. The source of the deeper plumes at Hook Ridge has yet to be located. We also explored a series of three parallel volcanic ridges west of Hook Ridge called Three Sisters. We detected water column anomalies indicative of venting with the ZAPS package and recovered hydrothermal barites and sulfides from Middle Sister. We spent considerable time photographing Middle Sister and Hook Ridge but did not identify classic vent fauna at either location. We either missed small areas with our photography or typical MOR vent fauna are absent at these sites.

  7. Hydrothermal processing method of producing zirconia from Malaysia zircon

    International Nuclear Information System (INIS)

    Zircon is the major source for zirconium and it is available in Malaysia as an associated mineral from the tin mining industry. Zirconium chemicals especially zirconia has found wide applications especially as advanced materials and in high technology industries. Production of high purity zirconia normally requires the used of very high temperature. Hydrothermal process provides an alternative to this aspect by incorporating low temperature technique. In this paper characteristics studies were performed on product obtained from this method to ascertain its crystalline phases, purity and also particle size. Study was also done to determine the effect of temperature on these characteristics. (Author)

  8. Hydrothermal Synthesis of Indium Tin Oxide Nanoparticles without Chlorine Contamination

    International Nuclear Information System (INIS)

    Indium tin oxide (In2Sn1-xO5-y) nanoparticles were synthesized by hydrothermal method from stable indium tin acetylacetone complexes and post annealing at 600 .deg. C. The absence of chlorine ions shortened the synthesis process, decreased the particle agglomeration and improved the particle purity. The introduced complexing ligand acetylacetone decreased the obtained nanoparticle size. The improved powder properties accelerated the sintering of the In2Sn1-xO5-y nanoparticles and reached a relative density of 96.4% when pressureless sintered at 1400 .deg. C

  9. Thermal stability of ESR signals in hydrothermal barites

    International Nuclear Information System (INIS)

    Thermal stability of the ESR signals from barites in chimneys deposited from hydrothermal vents is investigated using isothermal and isochronal annealing experiments. A combination of first and second order kinetics is required to explain the results. The Arrhenius plots of the decay rate constants give the activation energies of 1.0-1.3 eV. From the estimated decay rate constants at the sea bottom (3 oC), the decay rate of the signal was calculated to be less than 2% for the period of 20 ka, suggesting the applicability of the ESR method for dating barites up to about twenty thousand years.

  10. Feasibility of Hydrothermal Pretreatment on Maize Silage for Bioethanol Production

    DEFF Research Database (Denmark)

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2010-01-01

    The potential of maize silage as a feedstock to produce bioethanol was evaluated in the present study. The hydrothermal pretreatment with five different pretreatment severity factors (PSF) was employed to pretreat the maize silage and compared in terms of sugar recovery, toxic test, and ethanol...... production by prehydrolysis and simultaneous saccharification and fermentation. After pretreatment, most of the cellulose remained in the residue, ranging between 85.87% by the highest PSF (185°C, 15 min) and 92.90% obtained at the lowest PSF (185°C, 3 min). A larger part of starch, varying from 71...

  11. Evidence for recent hydrothermal activity in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; ShyamPrasad, M.; Gupta, S.M.; Charan, S.N.

    /89 and SS10/657 were mounted in epoxy, ground and polished to expose the internal features, and then sputter Hydrothermal activity in the Central Indian Basin 1169 8”Oo’. 16”0( Fig. 1. Physiographic features of the Central Indian Basin. FZ 1... determined with pure Ni and pyrite standards, respectively. The polished sections of the spherules were analysed on a flat surface with an accuracy of 0.1%. The ochrous sediments, due to their porous nature, gave lesser totals and hence only those totals...

  12. Hydrothermal synthesis of perovskite and pyrochlore powders of potassium tantalate

    OpenAIRE

    Goh, Gregory K. L.; Haile, Sossina M.; Levi, Carlos G.; Lange, Fred F.

    2002-01-01

    Potassium tantalate powders were hydrothermally synthesized at 100 to 200 °C in 4 to 15 M aqueous KOH solutions. A defect pyrochlore, Kta_(2)O_(5)(OH). nH2O (n ≈ 1.4), was obtained at 4 M KOH, but at 7–12 M KOH, this pyrochlore was gradually replaced by a defect perovskite as the stable phase. At 15 M KOH, there was no intermediate pyrochlore, only a defect perovskite, K_(0.85)Ta_(0.92)O_(2.43)(OH)_(0.57) 0.15H_(2)O. Synthesis at higher KOH concentrations led to greater incorporation of prot...

  13. Dissolved gases in hydrothermal plumes from Artic vent fields

    OpenAIRE

    Stensland, Anne

    2013-01-01

    Recent discoveries of active vent fields on slow and ultraslow spreading ridges have revealed that hydrothermal activity is more common than previously assumed. In the Norwegian-Greenland Sea, two such vent fields are found; the Jan Mayen vent fields (71°N and 6°E) and Loki`s Castle (73°30′N and 8°E). Both these systems are located on the ultraslow spreading Mohns Ridge, but they differ profoundly in the geochemical fluid and gas composition. This study presen...

  14. Fluid and gas fluxes from the Logatchev hydrothermal vent area

    OpenAIRE

    Schmale, Oliver; Walter, Maren; Schneider von Deimling, Jens; Sültenfuß, Jürgen; Walker, Sharon; Rehder, Gregor; Keir, Robin

    2012-01-01

    The Logatchev hydrothermal field at 14°45′N on the MAR is characterized by gas plumes that are enriched in methane and helium compared to the oceanic background. We investigated CH4 concentration and δ13C together with δ3He in the water column of that region. These data and turbidity measurements indicate that apart from the known vent fields, another vent site exists northeast of the vent field Logatchev 1. The distribution of methane and 3He concentrations along two sections were used in co...

  15. Direct synthesis of thermochromic VO2 through hydrothermal reaction

    Science.gov (United States)

    Alie, David; Gedvilas, Lynn; Wang, Zhiwei; Tenent, Robert; Engtrakul, Chaiwat; Yan, Yanfa; Shaheen, Sean E.; Dillon, Anne C.; Ban, Chunmei

    2014-04-01

    Thermochromic VO2 was directly synthesized using hydrothermal techniques. The effects of formation conditions on the structure and morphology of the final product were studied through X-ray diffraction (XRD), and scanning electron microscopy (SEM). Unique hollow sphere morphology was observed for the synthesized VO2 powders. Ex-situ XRD studies after heat treatment confirmed the thermal stability of the VO2 structure. Thermochromic properties, as a consequence of the reversible structural transformation between monoclinic VO2 and tetragonal phases, were observed by Fourier transform infrared spectroscopy (FTIR).

  16. A Novel Dual-Stage Hydrothermal Flow Reactor

    DEFF Research Database (Denmark)

    Hellstern, Henrik Christian; Becker, Jacob; Hald, Peter;

    2015-01-01

    . The dual-stage reactor combines the ability to produce advanced materials with an upscaled capacity in excess of 10 g/hour (dry mass). TiO2 was synthesized in the primary reactor and reproduced previous results. The dual-stage capability was succesfully demonstrated with a series of nanocomposites......The dual-stage reactor is a novel continuous flow reactor with two reactors connected in series. It is designed for hydrothermal flow synthesis of nanocomposites, in which a single particle consists of multiple materials. The secondary material may protect the core nanoparticle from oxidation and...

  17. Hydrothermal plume anomalies along the Central Indian Ridge

    Institute of Scientific and Technical Information of China (English)

    ZHU Jian; LIN Jian; GUO ShiQin; CHEN YongShun

    2008-01-01

    Water column turbidity and temperature were investigated along the Central Indian Ridge (CIR) from 25°19'S to 23°48'S during a December 2005 cruise on board Chinese P/V DayangYihao.Measurements were made using NOAA's MAPR (Miniature Autonomous Plume Recorder) sensors during CTD casts,TV grabber operations,and tow-yo profiles,yielding the following results on hydrothermal plume anomalies:(1) Strong hydrothermal turbidity and temperature anomalies were recorded over the pre-viously discovered Kairei (25°19.2'S,70°02.4'E) and Edmond (23°52.7'S,69°35.8"E) vent fields,with the plume anomalies concentrated at depths of 2150-2300 m and 2700-2900 m,respectively.The maxi-mum height of the turbidity anomalies near the Kairei vent field recorded in December 2005 was slightly below 2100 m,which is consistent with the plume depth measured in June 2001,indicating that the Kairei plume may have maintained its buoyancy flux in the intervening 4.5 years.(2) The water column beneath the Kairei plume has background anomalies of about 0.005△NTU,whereas no such back-ground turbidity anomalies were observed below the Edmond hydrothermal plume.(3) No visible tur-bidity anomalies were detected from 24°42'S to 24°12'S including the Knorr Seamount.Thus 24°12'S marks the southern end of the hydrothermal plume.(4) Significant turbidity anomalies were observed at four individual sections from 24°12'S to 23°56'S at the depth of 2500-3000 m along the eastern rift valley wall.Whether the individual sections of anomalies are connected is still unknown due to the absence of data at the intervening gaps.If the four sections are connected with each other and are linked to the Edmond vent field farther to the north,the total along-axis length of the plume anomaly would be more than 37 km,implying a plume incidence value Ph of 0.38,greater than the predicted Ph of 0.21-0.25 based on the spreading rate of the Central Indian Ridge.

  18. Thermal stability of ESR signals in hydrothermal barites

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Fumihiro [Department of Applied Physics, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005 (Japan); Toyoda, Shin, E-mail: toyoda@dap.ous.ac.jp [Department of Applied Physics, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005 (Japan); Banerjee, Debabrata [Department of Applied Physics, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005 (Japan); Planetary Sciences Division, Physical Research Laboratory, Ahmedabad 380009 (India); Ishibashi, Jun-Ichiro [Department of Earth and Planetary Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

    2011-09-15

    Thermal stability of the ESR signals from barites in chimneys deposited from hydrothermal vents is investigated using isothermal and isochronal annealing experiments. A combination of first and second order kinetics is required to explain the results. The Arrhenius plots of the decay rate constants give the activation energies of 1.0-1.3 eV. From the estimated decay rate constants at the sea bottom (3 {sup o}C), the decay rate of the signal was calculated to be less than 2% for the period of 20 ka, suggesting the applicability of the ESR method for dating barites up to about twenty thousand years.

  19. Parameterization of and Brine Storage in MOR Hydrothermal Systems

    Science.gov (United States)

    Hoover, J.; Lowell, R. P.; Cummings, K. B.

    2009-12-01

    Single-pass parameterized models of high-temperature hydrothermal systems at oceanic spreading centers use observational constraints such as vent temperature, heat output, vent field area, and the area of heat extraction from the sub-axial magma chamber to deduce fundamental hydrothermal parameters such as total mass flux Q, bulk permeability k, and the thickness of the conductive boundary layer at the base of the system, δ. Of the more than 300 known systems, constraining data are available for less than 10%. Here we use the single pass model to estimate Q, k, and δ for all the seafloor hydrothermal systems for which the constraining data are available. Mean values of Q, k, and δ are 170 kg/s, 5.0x10-13 m2, and 20 m, respectively; which is similar to results obtained from the generic model. There is no apparent correlation with spreading rate. Using observed vent field lifetimes, the rate of magma replenishment can also be calculated. Essentially all high-temperature hydrothermal systems at oceanic spreading centers undergo phase separation, yielding a low chlorinity vapor and a high salinity brine. Some systems such as the Main Endeavour Field on the Juan de Fuca Ridge and the 9°50’N sites on the East Pacific Rise vent low chlorinity vapor for many years, while the high density brine remains sequestered beneath the seafloor. In an attempt to further understand the brine storage at the EPR, we used the mass flux Q determined above, time series of vent salinity and temperature, and the depth of the magma chamber to determine the rate of brine production at depth. We found thicknesses ranging from 0.32 meters to ~57 meters over a 1 km2 area from 1994-2002. These calculations suggest that brine maybe being stored within the conductive boundary layer without a need for lateral transport or removal by other means. We plan to use the numerical code FISHES to further test this idea.

  20. Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

    Directory of Open Access Journals (Sweden)

    Apinpus Rujiwatra

    2011-01-01

    Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.