No. Registros Solicitud 1 5614 colombia
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CO - CODEN: RCCFAO AN - ACCESSION NUMBER: 2002-037927 UD - UPDATE CODE: 200213 Registro 567 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Consideraciones geocronologicas e isotopicas del Batolito Antioqueno Translated Title: Geochronologic and isotopic considerations of the Antioquian Batholith. AU - AUTHORS: Ordonez-Carmona-Oswaldo; Pimentel-Marcio-M AF - AUTHOR AFFILIATION: Universidad Nacional de Colombia, Facultad de Minas, Medellin, Colombia SO - SOURCE: Revista de la Academia Colombiana de Ciencias Exactas, Fisicas y Naturales. 25; 94, Pages 27-35. 2001. PB - PUBLISHER: Academia Colombiana de Ciencias Exactas, Fisicas y Naturales. Bogota, Colombia. 2001. CP - COUNTRY OF PUBLICATION: Colombia PY - PUBLICATION YEAR: 2001 LA - LANGUAGE: Spanish LS - LANGUAGE OF SUMMARY: English AB - ABSTRACT: The Antioquian batholith underlies an area of ca. 8000 km (super 2) being the largest calc-alkaline batholith in the Central Cordillera of the Colombian Andes. The batholith is made mainly of granodiorite and tonalite. Gabbroic and dioritic facies are recognized locally. The most widespread facies consists of a medium to coarse-grained granodiorite with quartz, k feldspar, plagioclase, hornblende, biotite, and accessory minerals. Nd isotopic compositions indicate epsilon (sub Nd) (T) values between -2.40 and +2.66 and T (sub DM) model ages ranging from 603 Ma to 1035 Ma. A whole-rock Rb-Sr isochron yielded an age of 98+ or -27 Ma, which is interpreted as the best estimate for age for of crystallization of the original magmas. DE - DESCRIPTORS: absolute-age; alkali-metals; alkaline-earth-metals; Andes-; Antioquia-Colombia; Antioquian-Batholith; batholiths-; calc-alkalic-composition; Central-Cordillera; coarse-grained-materials; Colombia-; Cretaceous-; dates-; diorites-; gabbros-; granites-; granodiorites-; igneous-rocks; intrusions-; isochrons-; isotope-ratios; isotopes-; lithofacies-; Lower-Cretaceous; Mesozoic-; metals-; Nd-144-Nd-143; neodymium-; Northern-Andes; plutonic-rocks; radioactive-isotopes; rare-earths; Rb-87-Sr-86; Rb-Sr; rubidium-; South-America; stable-isotopes; strontium-; tonalite- CC - CATEGORY CODES: 05A-Igneous-and-metamorphic-petrology; 03-Geochronology DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic MC - MAP COORDINATES: LAT: S060000; S050000; LONG: W0743000; W0751500. IL - ILLUSTRATION: Refs: 22; illus. incl. 3 tables, geol. sketch map. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0370-3908 CO - CODEN: RCCFAO AN - ACCESSION NUMBER: 2002-037926 UD - UPDATE CODE: 200213 Registro 568 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Evaluation of coal-bed methane potential of Colombia. AU - AUTHORS: Garcia-Gonzalez-Mario AF - AUTHOR AFFILIATION: Universidad Industrial de Santander, Bucaramanga, Colombia BK - BOOK TITLE: In: American Association of Petroleum Geologists 2000 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Annual Meeting Expanded Abstracts - American Association of Petroleum Geologists. 2000; Pages 52. 2000. PB - PUBLISHER: American Association of Petroleum Geologists and Society of Economic Paleontologists and Mineralogists (AAPG). Tulsa, OK, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 CN - CONFERENCE INFORMATION: American Association of Petroleum Geologists 2000 annual meeting. New Orleans, LA, United States. Apr. 16-19, 2000. LA - LANGUAGE: English AB - ABSTRACT: Three large regions of Colombia--the Cesar-Rancheria Basin, the Cordillera Oriental, and the Cauca Valley Basin--contain by virtue of their tremendous coal tonnage a large unrecognized coal-bed methane resource. However, this gas resource has been forgotten by the oil and gas industry of Colombia. In the Cesar-Rancheria Basin there are two large coal deposits, The Cerrejon and La Jagua, of Paleocene age. The Cerrejon area contains 55 coal-beds with some beds as thick as 25 meters. The gas resources of the Cerrejon area are estimated in 10 TCF. The La Jagua area present 60 coal-beds, some coal-beds are 10 meters thick. The gas resources are estimated in 4 TCF. In the cordillera Oriental there are two regions with coal deposit: The Cundinamarca-Boyaca region, where the Guaduas Formation of Maestrichtian to Paleocene age contains the largest coalbed resource of Colombia with a coalbed methane resource of 10 TCF. The coal-bearing region extends along the axis of the Cordillera Oriental. The Norte de Santander region has coal-beds ranging in age from Maestrichtian to Lower Oligocene. This area presents a large anticline-syncline structure with a gas coalbed methane resource of 1 TCF. In the Cauca Valley Basin the Guachinte Formation of Eocene to Oligocene age contains coal-beds characterized by a high hydrogen index, which are an excellent resource of methane and wet gases. The gas resource of this basin is 6.2 TCF. DE - DESCRIPTORS: aliphatic-hydrocarbons; alkanes-; Andes-; Cauca-Valley-Basin; Cenozoic-; Cesar-Rancheria-Basin; coal-; coalbed-methane; Colombia-; Cretaceous-; Eastern-Cordillera; evaluation-; Guaduas-Formation; hydrocarbons-; hydrogen-; industry-; lower-Oligocene; Maestrichtian-; Mesozoic-; methane-; natural-gas; Oligocene-; organic-compounds; Paleogene-; petroleum-; resources-; Santander-Colombia; sedimentary-rocks; Senonian-; South-America; Tertiary-; thickness-; Upper-Cretaceous CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0094-0038 CO - CODEN: APGAB2 AN - ACCESSION NUMBER: 2002-037333 UD - UPDATE CODE: 200213 Registro 569 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Isotopic studies of Northern Andean crustal evolution and ore metal sources. AU - AUTHORS: Macfarlane-Andrew-W AF - AUTHOR AFFILIATION: Florida International University, Department of Geology, Miami, FL, United States BK - BOOK TITLE: In: Geology and ore deposits of the Central Andes. BA - BOOK AUTHORS: Skinner-Brian-J (editor) SO - SOURCE: Special Publication - Society of Economic Geologists. 7; Pages 195-217. 1999. PB - PUBLISHER: Society of Economic Geologists. Littleton, CO, United States. 1999. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1999 LA - LANGUAGE: English AB - ABSTRACT: Ore lead isotope provinces in the central Andes between 6 degrees S and 32 degrees S correspond in part to broad differences in the ages and types of rocks exposed in each area. If these provinces reflect scavenging of lead from upper crustal rocks and reconcentration into ore deposits, ore lead isotope ratios reflect the average upper crustal composition in each region. If the ore metals have a deeper source, the provinces instead reflect differences in magma sources or generation processes among the provinces. Ores from province II (the high Andes of Peru) show steep lead isotope arrays indicative of source mixing. The igneous rocks in the Hualgayoc district in northern Peru overlap with the radiogenic end of the province I array and are representative of the nonradiogenic end of the province II mixing trends; exposed supracrustal rocks are candidates for the radiogenic end member. The origins of both isotopic signatures are investigated to examine the relationship between hydrothermal metal budgets and magma sources. The exposed crust in the northern Peruvian Andes consists of middle Cretaceous platform carbonates, sandstones, and shales that overlie a similar Jurassic sequence and probably a Precambrian to early Paleozoic metamorphic basement. The metamorphic basement and overlying sediments have broadly similar Pb-Sr-Nd isotope systematics. Whole-rock Pb isotope and U/P systematics of the sediments suggest U/Pb fractionation in the sediment source at approximately 1800 Ma, followed by evolution with elevated U/Pb ratios. epsilon (sub Nd) values of the metamorphic basement and Cretaceous sedimentary rocks range from -11.6 to -16.5, with T (sub DM) equal to 1.43 to 2.06 Ga. Northern Peru basement rocks have much higher (super 206) Pb/ (super 204) Pb values than metamorphic basement terranes in eastern Colombia, southern Peru, and northern Chile, and their isotopes more closely resemble basement terranes to the east in Brazil. The sedimentary rocks were intruded in the middle to late Miocene by numerous felsic igneous bodies associated with hydrothermal Ag-Zn-Cu-Pb mineralization. The intrusive rocks are intermediate to high K andesitic intrusions and rhyodacitic volcanic domes. Fresh igneous rocks have rare earth element (REE) abundances less than 100 times chondrites, lack significant Ce and Eu anomalies, and are relatively depleted in Ti and Nb. The isotopic compositions and homogeneity of the igneous rocks with respect to Pb, Sr, and Nd suggest that they assimilated little shallow crust and were derived largely from deeper sources in the upper sub-Andean mantle or the lower sub-Andean crust. Because no exposed Andean basement rocks resemble the compositions of province I ores, and because subducted sediment has recently been shown to be an important source of lead in arc magmas, the role of subducted sediment in producing a province I-like signature is evaluated. A simple numerical model for the enrichment of a possible mantle-wedge source region by subducted sediments is presented. The model suggests that subducted sediment can account for the lead isotope signature of province I ores, and that the quantity of subducted material along the Peru-Chile trench could produce a mantle source with this signature within a few million years of the onset of subduction. DE - DESCRIPTORS: actinides-; alkali-metals; alkaline-earth-metals; Andes-; Argentina-; basement-; Bolivia-; Chile-; copper-ores; Cretaceous-; crust-; isotope-fractionation; isotope-ratios; isotopes-; lead-; lead-ores; magmatism-; major-elements; mantle-; Mesozoic-; metal-ores; metals-; mineral-deposits,-genesis; mineral-exploration; Nd-144-Nd-143; neodymium-; Northern-Andes; Pb-206-Pb-204; Pb-207-U-235; Pb-208-Pb-204; Peru-; plate-tectonics; polymetallic-ores; radioactive-isotopes; rare-earths; Rb-87-Sr-86; rubidium-; silver-ores; South-America; Sr-87-Sr-86; stable-isotopes; strontium-; subduction-; thorium-; trace-elements; U-238-Pb-204; U-238-Pb-206; U-238-Th-232; uranium-; zinc-ores CC - CATEGORY CODES: 27A-Economic-geology,-geology-of-ore-deposits; 02D-Isotope-geochemistry DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 106; illus. incl. 3 tables, geol. sketch maps. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IB - ISBN: 1-887483-94-2 CO - CODEN: #03481 AN - ACCESSION NUMBER: 2002-036439 UD - UPDATE CODE: 200213 Registro 570 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Exploring the Ecuador-Columbia active margin and interplate seismogenic zone. AU - AUTHORS: Collot-J-Y; Charvis-P; Gutscher-M-A; Operto-S AF - AUTHOR AFFILIATION: Geosciences Azur, Observatoire de Villefranche, Villefranche-sur-mer, France SO - SOURCE: Eos, Transactions, American Geophysical Union. 83; 17, Pages 185, 189-190. 2002. PB - PUBLISHER: American Geophysical Union. Washington, DC, United States. 2002. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2002 LA - LANGUAGE: English DE - DESCRIPTORS: accretion-; active-margins; Colombia-; continental-margin; crust-; earthquakes-; Ecuador-; focal-mechanism; fracture-zones; geophysical-methods; geophysical-profiles; geophysical-surveys; intraplate-processes; magnitude-; Nazca-Plate; oceanic-crust; plate-tectonics; reactivation-; reflection-methods; seismic-methods; seismic-profiles; South-America; South-American-Plate; subduction-; surveys-; thrust-sheets CC - CATEGORY CODES: 18-Solid-earth-geophysics; 20-Applied-geophysics DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic MC - MAP COORDINATES: LAT: S030000; N010000; LONG: W0800000; W0820000. IL - ILLUSTRATION: Refs: 10; illus. incl. geol. sketch map, sects. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0096-3941 CO - CODEN: EOSTAJ AN - ACCESSION NUMBER: 2002-035492 UD - UPDATE CODE: 200212 Registro 571 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Massif anorthosite of Oaxaquia and its role in the tectonic evolution and correlation of the Mexican Grenville. AU - AUTHORS: Ortega-Gutierrez-Fernando; Schulze-Carlos; Solari-Luigi; Cameron-Ken; Keppie-John-Duncan; Lopez-Robert; Dostal-Jarda AF - AUTHOR AFFILIATION: Universidad Nacional Autonoma de Mexico, Inst. de Geologia, Mexico City, Mexico BK - BOOK TITLE: In: Geological Society of America, 2001 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 33; 6, Pages 292. 2001. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2001. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2001 CN - CONFERENCE INFORMATION: Geological Society of America, 2001 annual meeting. Boston, MA, United States. Nov. 1-10, 2001. LA - LANGUAGE: English AB - ABSTRACT: Massif anorthosite is an essential component of the continental crust that characterizes the Grenville orogens of Laurentia and Oaxaquia (Mexico); however, its origin remains problematic. In eastern Mexico, they occur within granulite facies inliers from Tamaulipas to Chiapas: Novillo (50% anorthositic rocks), Huiznopala (25%), northern Oaxaca (20%), southern Oaxaca (60%), and Guichicovi complexes (not found or minor). U-Pb zircon dates on these rocks (interpreted as magmatic ages) range between 998 and 1,010 Ma. Oaxaquia anorthosites are distinguished by the sodic composition of plagioclase (av. An35), and enrichment in P, Fe, Ti, Zr represented by nelsonitic bodies, and K and Si by modal quartz and antiperthite. Outcrops with plagioclase megacrysts and exsolved pyroxene, and inverted pigeonite (?) in thin section, demonstrate high temperatures and probably shallow levels of emplacement. These anorthosites are synchronous with intrusion of within-plate mafic and felsic rocks. The collisional Oaxacan orogeny, which immediately succeeded anorthosite emplacement in all cases, has been dated at 975-990 Ma, indicating 10-20 Ma between intrusion and burial to lower crustal depths. Accompanying granulite facies metamorphism produced granoblastic recrystallization of all minerals at intermediate to high pressures. These features of the Mexican anorthosites support correlation of all inliers of Oaxaquia and define a key element for the paleogeographic reconstruction of the Grenville belt. Considering their very young ages and pretectonic emplacement with respect to the Oaxacan orogeny, this block cannot represent a fragment of the Grenville belt detached from eastern Laurentia. Nor can it be correlated with the Australian and Texan belts, which lack anorthosite and have a different ages and protoliths. The anorthositic massifs in the Andean Grenville of Colombia and Venezuela, although not dated yet, may represent close correlatives of those in Oaxaquia, as supported by other data. The Oaxaquia anorthosites appear to have been emplaced during a rifting event of undetermined tectonic setting. DE - DESCRIPTORS: absolute-age; anorthosite-; Chiapas-Mexico; correlation-; dates-; facies-; gabbros-; geochemistry-; granulite-facies; Grenvillian-Orogeny; igneous-rocks; metamorphism-; Mexico-; mineral-composition; nesosilicates-; Oaxaca-Mexico; Oaxaquia-; orogeny-; orthosilicates-; paleogeography-; plate-tectonics; plutonic-rocks; Precambrian-; silicates-; Tamaulipas-Mexico; tectonics-; U-Pb; zircon- CC - CATEGORY CODES: 05A-Igneous-and-metamorphic-petrology; 16-Structural-geology DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States IS - ISSN: 0016-7592 CO - CODEN: GAAPBC AN - ACCESSION NUMBER: 2002-035094 UD - UPDATE CODE: 200212 Registro 572 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Geological controls on vegetation reflectance; an example from middle Magdalena Basin, Colombia. AU - AUTHORS: Baquero-Carlos-Mauricio; Vincent-Robert-K; Levine-Norman-S AF - AUTHOR AFFILIATION: Bowling Green State University, Department of Geology, Bowling Green, OH, United States BK - BOOK TITLE: In: Geological Society of America, 2001 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 33; 6, Pages 289. 2001. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2001. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2001 CN - CONFERENCE INFORMATION: Geological Society of America, 2001 annual meeting. Boston, MA, United States. Nov. 1-10, 2001. LA - LANGUAGE: English AB - ABSTRACT: Geologic mapping in mountainous vegetated terranes is difficult under the best conditions. Techniques that aid in remotely mapping the geology in these regions are very important to natural resource development in many lesser-developed nations. This study investigates the use of remote sensing data for improved mapping of these difficult regions. An unsupervised classification of a Landsat 7 image showed strong correlation to the geology of approx. 5000 km2 of a rugged and densely vegetated area in the Middle Magdalena Basin, suggesting a link between geobotanical signals and the underlying geology. Removal of topographic and atmospheric effects is a necessary prerequisite before exclusively geology-vegetation relationships can be determined to occur. In order to isolate and enhance the geologic signals within the dense vegetation, band-ratioing and terrain corrections were employed. The analysis was aided by the use of digital topography and other geospatial data sets to enhance the classification of the region's geology. A field-based geological map was used to divide the image into homogeneous lithological polygons, allowing us to multispectrally assess the correlation between vegetation and lithology. GIS-based analysis allowed us to recognize analogies and dissimilarities between lithologies. Land-use polygons (tropical forest, rangeland and crops) were employed to constrain the analysis. If relationships between the Geology and vegetation prove to be consistent in the Middle Magdalena Basin, similar multispectral patterns may be useful for discrimination among broad lithological groups in other tropical basins. This study shows that the combination of remote sensing and GIS can be an extremely useful tool for the production of preliminary geologic maps from multispectral remote sensing data in vegetated areas. DE - DESCRIPTORS: classification-; Colombia-; drainage-basins; geographic-information-systems; geomorphology-; information-systems; Landsat-; Magdalena-Valley; mapping-; multispectral-analysis; reflectance-; remote-sensing; South-America; surficial-geology; terrains-; vegetation- CC - CATEGORY CODES: 23-Geomorphology DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States IS - ISSN: 0016-7592 CO - CODEN: GAAPBC AN - ACCESSION NUMBER: 2002-035078 UD - UPDATE CODE: 200212 Registro 573 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: New insights on the Eastern Cordillera, Colombia. AU - AUTHORS: deGruyter-Phil-C; Wu-Schuman; Mora-Miguel; Sadler-Peter; Achem-Eduardo; Villamil-Tomas; Rowan-Mark-G; Franks-Steve-G AF - AUTHOR AFFILIATION: Repsol-YPF, Englewood, CO, United States BK - BOOK TITLE: In: American Association of Petroleum Geologists 2001 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Annual Meeting Expanded Abstracts - American Association of Petroleum Geologists. 2001; Pages 49. 2001. PB - PUBLISHER: American Association of Petroleum Geologists and Society of Economic Paleontologists and Mineralogists (AAPG). Tulsa, OK, United States. 2001. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2001 CN - CONFERENCE INFORMATION: American Association of Petroleum Geologists 2001 annual meeting. Denver, CO, United States. June 3-6, 2001. LA - LANGUAGE: English AB - ABSTRACT: The Eastern Cordillera represents the "heart" of Colombia's petroleum system, but in spite of providing the charge for giant oilfields (Cusiana, Cupiagua, Cano Limon) it is mainly viewed as an uplifted and eroded paleo-kitchen with little remaining exploration potential. It is one of the best examples of large-scale basin inversion, evolving from a 7000+ m deep basin to a 5000 m high Cordillera, but our understanding is limited by interpretational inconsistencies and lack of data. Prior to investing in costly regional seismic and wells, an effort is underway to produce an internally consistent model that fully integrates all the structural, stratigraphic and thermal elements with new geochronologic constraints, including fluid inclusion and AFTA data. 1) The extremely thick shallow water Cretaceous synrift and sag sequences have never been adequately explained. Either very large amounts of rift-induced accommodation space and sub-aerial paleo-topography existed by the end of the Hauterivian (>2000-3000 m) or active extension continuously created the necessary accommodation space during much more of the Cretaceous than previously considered. 2) Previous studies have wide discrepancies in the Cenozoic compressional phases in terms of inversion and high-angle faulting versus low-angle thrusting, the amount of shortening ( approximately 2x differences), the position of basement (differences of 1000s of meters) and the timing and sequence of the different compressional pulses and uplifts. We provide new insights into subsidence, sedimentation, and tectonic evolution in the Mesozoic extensional and Cenozoic compressional stages of the Cordillera which have direct impacts on thermal and maturity models and hydrocarbon assessment for the region. DE - DESCRIPTORS: Andes-; Cano-Limon-Field; Cenozoic-; Colombia-; compression-tectonics; Cretaceous-; crustal-shortening; Cupiagua-Field; Cusiana-Field; Eastern-Cordillera; evaluation-; extension-tectonics; faults-; fluid-inclusions; genesis-; giant-fields; Hauterivian-; high-angle-faults; inclusions-; low-angle-faults; Lower-Cretaceous; maturity-; Mesozoic-; models-; oil-and-gas-fields; petroleum-; petroleum-exploration; sedimentation-; South-America; subsidence-; tectonics-; thickness-; thrust-faults; uplifts- CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0094-0038 CO - CODEN: APGAB2 Yüklə 20,82 Mb. Dostları ilə paylaş:
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