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Pesce, A.H; 2000. 31er. Congreso Geológico Internacional. CD Ron. Abstract A remarkable geothermal development has been produced in the past few years in northeast Argentina. A large sedimentary basin, known as Chaco-Paraná, occurs with two aquifers bearing thermal fluids. For the analysis of the basin, 200 deep oil exploration wells, distributed in Argentina, Brazil and Uruguay have been processed and by means of 3-D modeling.For this work, a single stratigraphic column was adopted taking into account fascies changes, correlation, stratigraphy, chronosatratigraphy, and paleochrono-stratigraphy. Also, generalizations and chronostratigraphic grouping from the different sub-basins were performed. The correlation of formations becomes a methodological necessity, since the study compromises a huge area not covered completely by a single geological unit. As a consequence of this, the stratigraphic divisions produced by underground exploration, showing large sedimentary cycles, usually coinciding with transgressive and/or regressive stages, or those separated by significant regional discordances, produced by continental orogeny, were preferred. Through 3D modeling, thicknesses, evolution and geometry of the basin were reconstructed, showing its conection with the Parana basin in southern Brazil. Isopach and basin maps for each considered stratigraphic unit were produced as a guide to geothermal exploration in northeastern Argentina..The study of neopaleozoic-eopermian fluvial, lacustrine, glacial and glacimarine Sachayoj, Charata and Chacabuco Formations, and triassic-jurassic continental sandstones of the Tacuarembó and Rivera Formations was emphasized, since this units host the thermal aquifers under research.
Abel H. Pesce and Pablo E. Johanis; 2000. 31er. Congreso Geológico Internacional. CD Ron. Abstract There are two thermal aquifers located within the large Chaco-Paraná Basin located near the borders of Argentina, Brazil, Paraguay, and Uruguay. The deeper and more saline aquifer is located within glacial-marine deposits of Lower to Mid Permian age. The shallower aquifer is located in Triassic-Upper Jurassic eolian sandstones. The aquifers are located in an intracratonic area with normal to low geothermal gradients near 20º C/km. The aquifer temperatures are near 45ºC and the wells are capable of producing as much as 450 m3/hr. An analysis of 200 deep oil exploration wells shows that temperatures of 70ºC can be expected at depth of 2,200m in the deeper aquifer. Temperatures of 55ºC can be expected below a depth of 1,100m in the shallower aquifer. Six geothermal wells have been drilled in the area of depths of 1,100 to 1,500m and have wellhead temperatures of 30 to 46ºC These wells form the basis for recent four thermal spa type developments that mark the begining of a new tourist industry in Entre Rios Province in northeastern Argentina.
Johanis, P. E. and Miranda, F. J.; 2000. 31er. Congreso Geológico Internacional. CD Rom. Abstract Since 1995 several geothermal wells have been drilled and projected in NE Argentina, planned imitating similar wells in Uruguay and southern Brazil, without a proper basin analysis. Some of them reached thermal aquifers hosted in triassic-jurassic eolian sandstones, or in carboniferous-permian glacimarine sediments, at depths up to 1200 m. The potential of the geothermal resource is high, inspite of the low regional gradient, due to the subcontinental extension of the aquifers. Its sustainable development trough direct uses such as balneotherapy, house heating, greenhouses and agroindustrial processes, based on the comprehension of the underground geology, will be a challenge for the third milennium. A stratigraphic and hydrogeological knowledgebase of the Chaco-Parana intracratonic basin was builded, in order to gather all the basic geological data, and to model it three-dimensionally. The knowledgebase was developed on a GIS frame, including information of northeastern Argentina, Uruguay, southern Brazil and eastern Paraguay, due to the continuity of the underground geological features. Oil wells, deep water wells and outcrop data were included and calibrated with geophysical surveys. The model predicts position, thickness, cover and temperature of the aquifers, states areas of maximum potential, and allows an appropiate drilling planning.Geochemistry of underground waters was also carried out, through sampling of thermal wells in the area, to establish chemical and isotopic features of the aquifers. The study allowed to distinguish an upper, fresh water thermal aquifer, and a lower salty thermal one. An environmental assessment at some thermal locations was supported on the hydrogeochemical analysis, with recommendations for a sustentable use strategy.
Miranda F.J. y P. Johanis, 2000. Proceedings World Geothermal Congress 2000, Kyushu-Tohoku, Japan, May 28 - June 10, 2000. p: 1437-1441. Abstract The region of "El Ramal Jujeño" is located in the eastern part of Jujuy province, northwest Argentina. The zone has several spots with thermal manifestations, mainly warm springs. Reconnoisance studies were able to delimit three locations with surface spring temperatures ranging between 37° and 58°C: Aguas Calientes de Caimancito, Laguna La Quinta and Termas El Palmar. Detailed geological and geochemical surveys were carried out in order to evaluate their individual characteristics as well as to develope a conceptual model for the whole area. The thermal system ocurrs in a Cretaceous-Recent sedimentary basin, more than 5 kilometers thick. A main structural system striking NNE characterizes the region and is responsable for spring occurrences paralell to the western foothill of the Santa Barbara range. Geochemical surveys showed that each location has its own water type, related to its circulation depths. Isotopic determinations indicate that thermal waters have a meteoric origin with a recharge area located west of the areas of interest, where permeable strata that host aquifers crop out. Chemical geothermometers permit estimation of subsurface temperatures ranging between 80° to 125°C, related to deep groundwater circulation under a normal geothermal gradients as the heat source. The western Santa Barbara range foothills is the preferential area for drilling in order to obtain high temperatures at shallower depths, as shown by old exploration oil wells in this zone.
Miranda F. J. y A. H. Pesce, 2000. Proceedings World Geothermal Congress 2000, Kyushu-Tohoku, Japan, May 28 - June 10, 2000. p: 1443-1445. Abstract Increasing interest in exploitation and development of geothermal resources has led the Argentine Mining-Geological Survey (SEGEMAR) to elaborate the Catalogue of Thermal Manifestations of the Argentina Republic. Objectives were to generate a systematic and complete data base gathering all the available information of the country geothermal resources and to create a friendly source of consultation in order to contribute to the diffusion of the knowledge on the resources in Argentina. The catalogue itself constitutes a compilation of the bibliography from published and unpublished research, conducted by governmental organizations, scientific institutions, private companies and studies performed in-house. Arranged in order to allow any interested person to find the information easily, all data for each manifestation is provided in tables that include location, general characteristics (temperatutre, flow rates, etc.) chemical analyses, geothermometry and bibliography. Design, examples and implications of the catalogue are presented in this paper.
Miranda F.J., A. H. Pesce y E.G.Garea,1998. X Congreso Latinoamericano de Geología y VI de Geología Economica. Actas III. 410-415. Abstract A case study on pollution caused by thermal waters in the Villa Elisa City, Entre Ríos Province. The chemical and thermal contrast between the thermal fluids of the Villa Elisa-1 deep well, located in Villa Elisa, Entre Ríos Province, and those of the surficial streams of the area cause the drainage of the thermal fluid on them to vary and harm their natural conditions. The thermal and compositional variations are reflected at different rates along the streams involved, depending on the original compositions of the fluids available for mixing, the flowrates and circulation speed of waters, etc. The treatment of thermal efluents has become difficult by its extreme salinity. Although there are several treatment systems and methods for this type of fluids, its application, in some cases, results hardly feaseable due to the lack of adequate infraestructure and its cost.
Pesce A.H, F. J. Miranda, M. D. Vazquez Herrera y E.G.Garea,1998. X Congreso Latinoamericano de Geología y VI de Geología Economica. Actas III p. 409.
Pesce A.H, F. J. Miranda, P. Johanis y E.G.Garea,1998. X Congreso Latinoamericano de Geología y VI de Geología Economica. Actas III 403-408. Abstract The area knows as El Ramal Jujeño is located en the Santa Barbara Dept., eastern part of the Jujuy Province. This zone is characterized by several thermal areasdistributed paralel te the western foothill of the Santa Barbara range. Due is characteristics, Laguna La Quinta was selected as an interesting area for patential developmetn of economics applications by means of direct use of thermal fluids. Surface studies carried out in the area led to inferr a preliminar geothermal model, in which the recharge area would be located at the foothill of the Zapla and Valle Grande ranges and its heat source wuold be the regional geothermal Gradient. The hot springs are contained in the Yacoraite Fm. deposits, and their upward flow sould be related to the interaction of NNE, NW and ENE fault systems, corresponding to the tectonical model of the area. The fluids are meso- and hipo-thermal with a surface temperature ranging from 37° to 53°C. They are sodium chloride waters whith a strong mineralization. The temperature in the reservoir would be whitihn a range of 100° to 120°C.
Miranda F.J., A. H. Pesce, M. D. Vazquez Herrera and O.E. Theaux,1998. Proceedings of the 19th Annual PNOC-EDC Geothermal Conference, Manila, Philippines. p: 325-327. Abstract The Colorado basin is located at the south-western of Buenos Aires province and is characterised by its low temperature (55-80° C) artesian aquifers. Ground water resources are abundant and of good quality, being exposed in more than 70 deep wells. Main use of thermal waters at Bahía Blanca area, the commercial center of the region, is for domestic supply, but during the last few years other uses such as space heating, mineral water, food processing, fish farming and more recently greenhouses have been developed. Climatic conditions at this region makes Bahía Blanca an area difficult for greenhouses management, but the use of geothermal fluids in heating installations provided a good alternative for this purpose. Results obtained in a first pilot experience, with a heated area of 660 m2, encouraged producers to develop this as an industrial activity. The present production area reaches 2,500 m2 geothermally heated, attempting to increase to 5,000 m2 in the next years. Techniques employed allowed to get a more efficient and profitable productive cycle and to extend the commercialisation area.
Miranda F.J. and Pesce A. H., 1997. Geothermal Resources Council Transactions, Volume 21, "Meeting the Challenge of Increasing Competition" p: 337-339. Abstract The article synthesizes the evolution of the research and development of geothermal resources in Argentina through the years. In addition, we emphasize how the progress in the knowledge of this country’s resources has changed the objectives from electric power generation to the current tendency of direct use of heat.
Miranda F.J., Pesce A.H. , Johanis P. y Garea E.G.,1997. I Congreso Nacional de Hidrogeología, Bahía Blanca. Actas I, 211-220. Abstract El Ramal Jujeño is located in the eastern part of Jujuy province (Santa Bárbara department). This zone has many areas with thermal manifestations, mainly hot springs, that occur along the west border of Santa Barbara range. El Palmar, one of these areas, was selected to carry out geochemical studies aiming to evaluate, preliminarily, the characteristics of the thermal fluids. The hot springs, with temperatures ranging between 42° y 51°C, belongs to the sulphate type. Chemical and physical variations allowed to delimitate two groups of springs within the area; both of them with similar origin but different evolution as the water rises to the surface. Geochemical geothermometers allows to estimate a subsurface temperatures between 100° and 125°.
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