No. Registros Solicitud 1 5614 colombia
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DE - DESCRIPTORS: accuracy-; acoustical-methods; algorithms-; Caballos-Formation; Colombia-; elastic-constants; geophysical-methods; geophysical-surveys; inverse-problem; mathematical-methods; neural-networks; petroleum-; petroleum-exploration; Poisson'-s-ratio; probability-; Puerto-Colon-Field; reservoir-properties; reservoir-rocks; seismic-methods; South-America; spectral-analysis; stacking-; statistical-analysis; surveys-; well-logs CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources; 20-Applied-geophysics DT - DOCUMENT TYPE: Thesis-or-Dissertation BL - BIB LEVEL: Monograph NN - ANNOTATION: Includes appendices and a CD-ROM. IL - ILLUSTRATION: Refs: 38; illus. incl. 6 tables. RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. AN - ACCESSION NUMBER: 2005-011244 UD - UPDATE CODE: 200505 Registro 826 de 5614 - GeoRef : 2005/01-2005/07 BK - BOOK TITLE: Approaches for lithologic prediction using seismic attributes and geologic trends; Balcon Field, Colombia. BA - BOOK AUTHORS: Calderon-Jose-Ernesto CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2003 DG - DEGREE GRANTED: Master's DI - DEGREE GRANTING INSTITUTION: University of Oklahoma. Norman, OK, United States. Pages: 81. 2003. LA - LANGUAGE: English AB - ABSTRACT: This study presents the results of combining rock-physics, seismic attributes and multiattribute transforms in an effort to predict the spatial distribution of reservoir properties of Cretaceous aged sandstones from the Balcon Oil Field (BOF), located in the Neiva basin, Upper Magdalena Valley, Colombia. In this area, structural and stratigraphic factors control the hydrocarbon accumulation and production which come from quartz-sandstones of the Caballos Formation deposited in a fluvial-deltaic environment. This study, which developed out of a need to better understand the significance of seismic amplitude variations at the reservoir level and their relationships with rock properties, determined that acoustic related seismic attributes (velocity and acoustic impedance) are sensitive to changes in rock porosity and lithology. In spite of the high scatter observed in the cross-plots, due to factors such as composition, clay content, diagenesis and texture of the rock, three main rock physics trends are recognized. Thus, the lower stratigraphic unit, which is composed of poorly-sorted and "dirty" fluvial sandstones with high clay content, has higher velocity and lower porosity than the upper stratigraphic unit, which is composed of well-sorted and clean deltaic sandstones. The middle stratigraphic unit, which is mainly composed of marine shales with high clay content, has the lowest porosity and velocity. Cross-plots also indicate that porosity-velocity and porosity-acoustic impedance relation are greatly improved when stratigraphic constraints are used. It is demonstrated that the acoustic impedance attribute derived from model-based inversion can be used as the main seismic attribute to estimate spatial distribution of rock properties in the BOF. If this attribute is combined with other seismic attributes in linear or non-linear mode, the match between well-log derived properties and predicted values is improved to a great extent. A new method based on multiattribute transforms allows the interpreter to select the input seismic attributes to predict porosity derived from density log and gamma ray log (GR). Thus, for porosity prediction, the combination of the attributes 1/(impedance), filter 15/20-25/30 and time yield the best result. For GR prediction the most significant attributes are (impedance), time and band-pass filter seismic with the band 15/20-25/30 Hertz. DE - DESCRIPTORS: acoustical-methods; amplitude-; Balcon-Field; Caballos-Formation; clastic-rocks; Colombia-; Cretaceous-; deltaic-environment; depositional-environment; elastic-waves; fluvial-environment; geophysical-methods; geophysical-surveys; lithostratigraphy-; Magdalena-Valley; Mesozoic-; methods-; Neiva-Basin; passband-filters; petroleum-; porosity-; reservoir-properties; reservoir-rocks; sandstone-; sedimentary-rocks; seismic-methods; South-America; stratigraphic-units; surveys-; well-logging CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources; 20-Applied-geophysics DT - DOCUMENT TYPE: Thesis-or-Dissertation BL - BIB LEVEL: Monograph IL - ILLUSTRATION: Refs: 51; illus. incl. 7 tables. RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. AN - ACCESSION NUMBER: 2005-011242 UD - UPDATE CODE: 200505 Registro 827 de 5614 - GeoRef : 2005/01-2005/07 TI - TITLE: The mineralogy and geochemistry of the Cerro Matoso S.A. Ni laterite deposit, Montelibano, Colombia. AU - AUTHORS: Gleeson-S-A; Herrington-R-J; Durano-J; Velasquez-C-A; Koll-G AF - AUTHOR AFFILIATION: Natural History Museum, Department of Mineralogy, London, United Kingdom SO - SOURCE: Economic Geology and the Bulletin of the Society of Economic Geologists. 99; 6, Pages 1197-1213. 2004. PB - PUBLISHER: Economic Geology Publishing Company. Lancaster, PA, United States. 2004. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2004 LA - LANGUAGE: English AB - ABSTRACT: The Cerro Matoso S.A. Ni laterite deposit in northwest Colombia is an important producer of ferronickel; expanded production of ferronickel is planned to be 55,000 Mt by mid-2004. The deposit is developed over a peridotitic protolith that is exposed in the form of an elongated hill. The deposit's weathering profile is variable both vertically and laterally, and 10 distinct lithostratigraphic units have been characterized. Two typical sections through the weathering profile were sampled from an area of the mine with high (pit 1) and lower (pit 2) Ni grades. Bench mapping has shown that pits 1 and 2 have distinctly different weathering profiles. From bottom to top, the profile in pit 1 is weakly serpentinized peridotitic protolith-->saprolitized peridotite-->green saprolite (main ore horizon)-->"tachylite" (used by mine geologists to describe an enigmatic Fe oxide horizon)-->black saprolite-->yellow laterite-->red laterite. The sequence is then capped by a magnetic to nonmagnetic ferricrete known locally as "canga." The succession in pit 2 is from serpentinized peridotite-->saprolitized peridotite-->brown saprolite-->yellow laterite-->red laterite and lacks the green saprolite ore horizon. All the units in pit 2 have currently uneconomic Ni grades. The thickness of the units is highly variable, but most of the major horizons have maximum thicknesses of the order of tens of meters. Both pits contain abundant fault- and joint-related silicate veins, sometimes in stockworks, in the lower part of the sequence. These veins contain the distinctive green mineral known as "garnierite" (actually pimelite, a form of nickeliferous talc) as well as quartz and chalcedony, and they can have a Ni content of up to 30 to 40 wt percent. The bulk geochemistry in most units of both profiles shows a fairly typical Ni laterite pattern, in which MgO and SiO (sub 2) are depleted toward the top of the sequence whereas FeO increases. Mineralogic studies confirm that the protolith in both pits is a partly (up to 50%) serpentinized harzburgite and that, in pit 1, the main Ni-bearing phases in the weathering profile are Ni sepiolite, Ni serpentines, and other hydrous silicates. The garnierites in Cerro Matoso have been identified as pimelite in which various amounts of Ni have substituted for Mg. The upper part of the sequence is dominated by amorphous and crystalline Fe oxide phases. The magnetic canga is composed mainly of maghemite that may have been produced by oxidation of magnetite-rich units. The mineral content of pit 2 is dominated by poorly structured Fe oxides or goethite and by subordinate clay minerals and quartz. The geochemistry and mineral content of the deposit suggest that, as in many other Ni laterite deposits, ore genesis is strongly controlled by local climate, topography, and drainage. Mass balance calculations indicate that the profiles in pits 1 and 2 had different weathering histories, because the degree of profile collapse and residual enrichment in pit 1 is far more extreme than that in pit 2. This difference may be the result of different degrees of serpentinization of the protolith in the two pits and potential dilution of the ore in pit 2 by input from an exotic unit. Ni in the deposit has also undergone supergene enrichment resulting from the leaching of Ni from the upper part of the lateritic profile and its transport to the green saprolite unit, where the Ni was fixed in silicate minerals. DE - DESCRIPTORS: bulk-density; Cauca-Complex; Cerro-Matoso-Deposit; chemical-composition; Colombia-; controls-; Cordoba-Colombia; electron-probe-data; emission-spectra; geochemistry-; horizons-; igneous-rocks; laterites-; laterization-; mapping-; mass-balance; metal-ores; metasomatism-; mineral-composition; mineral-deposits,-genesis; Montelibano-Colombia; nickel-ores; northwestern-Colombia; peridotites-; pH-; plutonic-rocks; production-; protoliths-; quantitative-analysis; sampling-; serpentinization-; soils-; South-America; spectra-; stockwork-deposits; thickness-; thin-sections; ultramafics-; veins-; weathering-; whole-rock; X-ray-diffraction-data CC - CATEGORY CODES: 27A-Economic-geology,-geology-of-ore-deposits DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic MC - MAP COORDINATES: LAT: N073000; N080000; LONG: W0750000; W0760000. IL - ILLUSTRATION: Refs: 25; illus. incl. sect., 4 tables, sketch maps. RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. IS - ISSN: 0361-0128 CO - CODEN: ECGLAL AN - ACCESSION NUMBER: 2005-010385 UD - UPDATE CODE: 200505 Registro 828 de 5614 - GeoRef : 2005/01-2005/07 TI - TITLE: Interhemispheric comparison of late Quaternary pollen records from neotropical savanna environments. AU - AUTHORS: Behling-Hermann; Hooghiemstra-Henry AF - AUTHOR AFFILIATION: University of Amsterdam, Department of Palynology and Paleo/Actuo-ecology, Amsterdam, Netherlands BK - BOOK TITLE: In: AMQUA 1998; American Quaternary Association program and abstracts of the 15th biennnial meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Program and Abstracts - American Quaternary Association. Conference. 15; Pages 87. 1998. PB - PUBLISHER: American Quaternary Association. Seattle, WA, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AMQUA 1998; American Quaternary Association 15th biennnial meeting. Puerto Vallarta, Mexico. Sept. 5-7, 1998. LA - LANGUAGE: English DE - DESCRIPTORS: Amazon-Basin; Cenozoic-; Colombia-; forests-; Holocene-; last-glacial-maximum; Llanos-Orientales; microfossils-; miospores-; paleoecology-; palynomorphs-; pollen-; Quaternary-; savannas-; South-America; species-diversity; upper-Quaternary CC - CATEGORY CODES: 24-Quaternary-geology DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. IS - ISSN: 0741-059X CO - CODEN: AMQUAM AN - ACCESSION NUMBER: 2005-009385 UD - UPDATE CODE: 200504 Registro 829 de 5614 - GeoRef : 2005/01-2005/07 TI - TITLE: Tectonic reconstruction of the Northern Andean blocks; oblique convergence and rotations derived from the kinematics of the transpressional Piedras-Girardot Foldbelt, Colombia. AU - AUTHORS: Montes-Camilo AF - AUTHOR AFFILIATION: Institute Francais du Petrole, Division Geologie-Geochimie, Rueil Malmaison, France BK - BOOK TITLE: In: Geological Society of America, 2002 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 34; 6, Pages 488. 2002. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2002. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2002 CN - CONFERENCE INFORMATION: Geological Society of America, 2002 annual meeting. Denver, CO, United States. Oct. 27-30, 2002. LA - LANGUAGE: English AB - ABSTRACT: The tectonic configuration of the northern Andean blocks is reconstructed by defining three continental blocks in the northern Andes: the rigid Maracaibo (MB) block, the rigid Cordillera Central block (CCB), and the weak Cordillera Oriental (COB) block. Rigid blocks accomodate the oblique convergence imposed by the relative eastward motion of the Caribbean Plate as rotations and translations, whereas weak blocks, product of attenuated crust by rifting, accomodate oblique deformation by distortion and dilation. The weaker COB records large values of shear strain and shortening consistent with measurements made in the Piedras-Girardot foldbelt (PG). Published paleomagnetic data indicates that the stronger MB records large clockwise tectonic rotations. The CCB should record smaller values shear strain and convergence, but larger values of northward translation according to this model. These strain values, timing of deformation, and structural styles were derived from detailed analyses made in the PG and are compatible with published studies of kinematics in the northern Andes. Finite deformation in the PG is defined by a shear strain of 1.53 and a convergence factor of 2.03 within a N45E trending shear zone that records tectonic escape due to the ENE insertion of a rigid block. This deformation began during early Campanian times with incipient propagation of NE-trending faults that uplifted gentle domes where the accumulation of the sands did not take place. Unroofing during Maastrichtian times of a metamorphic terrane west of the Piedras-Girardot foldbelt is documented by a conglomerate that was deformed shortly after deposition developing a conspicuous intragranular fabric of microscopic veins that accommodate between 1 and 2 percent extension in a general NE-SW direction. This extensional fabric, distortion of fossil molds, and a moderate cleavage accomodating less than 5 percent contraction in a general NW-SE direction, developed concurrently, during and after the incipient folding, but before large scale faulting and folding took place during Paleogene times. Folding and thrust sheet propagation during Paleogene times is recorded by syntectonic strata and records westward to southwestward propagation of the faults. Neogene deformation took place only in the western flank of this foldbelt. DE - DESCRIPTORS: Andes-; Caribbean-Plate; Caribbean-region; Cenozoic-; Central-Cordillera; cleavage-; Colombia-; crust-; crustal-shortening; deformation-; Eastern-Cordillera; extension-tectonics; fabric-; faults-; folds-; foliation-; kinematics-; Neogene-; Northern-Andes; orientation-; Paleogene-; Piedras-Girardot-fold-belt; plate-convergence; plate-rotation; plate-tectonics; reconstruction-; rifting-; shear-; South-America; strain-; strength-; structural-analysis; tectonics-; Tertiary- CC - CATEGORY CODES: 16-Structural-geology DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2005, 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: 2005-009250 UD - UPDATE CODE: 200504 Registro 830 de 5614 - GeoRef : 2005/01-2005/07 TI - TITLE: Comparacion entre el metamorfismo de la cuenca de Cameros y el de la cuenca aurifera de Witwatersrand (Surafrica); implicaciones metalogeneticas Translated Title: Comparison between the metamorphism of Cameros Basin and that of the Witwatersrand gold bearing basin, South Africa; metallogenetic implications. AU - AUTHORS: Mantilla-Figueroa-L-C; Casquet-C; Mas-J-R AF - AUTHOR AFFILIATION: Univ. Ind. Santander, Esc. Geol., Bucaramanga, Colombia SO - SOURCE: Geogaceta. 25; Pages 131-134. 1999. PB - PUBLISHER: Sociedad Geologica de Espana. Madrid, Spain. 1999. CP - COUNTRY OF PUBLICATION: Spain PY - PUBLICATION YEAR: 1999 CN - CONFERENCE INFORMATION: 25. sesion cientifica de la Sociedad Geologica de Espana. Madrid, Spain. 1998. LA - LANGUAGE: Spanish LS - LANGUAGE OF SUMMARY: English DE - DESCRIPTORS: Africa-; Cameros-Basin; Castilla-y-Leon-Spain; Europe-; gold-ores; high-grade-metamorphism; hydrothermal-alteration; Iberian-Peninsula; Logrono-Spain; metal-ores; metallogeny-; metamorphism-; metasomatism-; mineral-deposits,-genesis; Soria-Spain; South-Africa; Southern-Africa; Southern-Europe; Spain-; Witwatersrand- CC - CATEGORY CODES: 27A-Economic-geology,-geology-of-ore-deposits DT - DOCUMENT TYPE: Serial; Conference-Document BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 17 RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. Reference includes data from Instituto Geologico y Minero de Espana, Madrid, Spain IS - ISSN: 0213-683X CO - CODEN: #52651 AN - ACCESSION NUMBER: 2005-008855 UD - UPDATE CODE: 200504 Registro 831 de 5614 - GeoRef : 2005/01-2005/07 TI - TITLE: Seismotectonics of the Northern Andes (Colombia) and the development of seismic networks. AU - AUTHORS: Pulido-Nelson AF - AUTHOR AFFILIATION: National Research Institute for Earth Science and Disaster Prevention, Earthquake Disaster Mitigation Research Center, Ibaraki, Japan SO - SOURCE: Bulletin of the International Institute of Seismology and Earthquake Engineering. Special edition; Pages 69-76. 2003. PB - PUBLISHER: International Institute of Seismology and Earthquake Engineering. Tokyo, Japan. 2003. CP - COUNTRY OF PUBLICATION: Japan PY - PUBLICATION YEAR: 2003 LA - LANGUAGE: English AB - ABSTRACT: Colombia is located in the Northern Andes were three tectonic plates converge; the Nazca, Caribbean and South American plates. This convergence produce active N-NE faulting within the so called Andean block. Very active seismicity is associated with the subduction of the Nazca plate as well as the Caribbean plate underneath the South American plate. Shallow seismicity from the two main fault systems in Colombia (The Romeral Fault System and the Eastern Cordillera Frontal Fault System) is also very active. Tomographic studies of local seismicity have resolved the 1-D crustal velocity structure as well as delineated the crustal attenuation regions of Colombia. Focal mechanism solutions and stress tensor analysis of aftershocks from large earthquakes, as well as GPS studies in Colombia have improved the understanding of the tectonic stress within the crust. Very destructive crustal and subduction earthquakes in Colombia during this century, have produced large economic and life loss. This highlights the importance of improving the knowledge of the seismic hazard in Colombia to contribute to the earthquake disaster mitigation in the future. DE - DESCRIPTORS: active-faults; Andes-; Colombia-; earthquakes-; Eastern-Cordillera; faults-; focal-mechanism; geologic-hazards; mitigation-; neotectonics-; Northern-Andes; Romeral-fault-system; seismic-networks; seismicity-; seismotectonics-; South-America; tectonics- CC - CATEGORY CODES: 16-Structural-geology; 22-Environmental-geology DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 24; illus. incl. 1 table, sketch maps. RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. IS - ISSN: 0074-655X CO - CODEN: IISBB2 AN - ACCESSION NUMBER: 2005-008347 UD - UPDATE CODE: 200504 Registro 832 de 5614 - GeoRef : 2005/01-2005/07 TI - TITLE: Establishment and maintenance of a gravity network in the Caribbean. AU - AUTHORS: Sliwa-Ludwik; Barriot-Jean-Pierre AF - AUTHOR AFFILIATION: Polytechnic University of Puerto Rico, PRI, Puerto Rico SO - SOURCE: Bulletin d'Information - Bureau Gravimetrique International. 91; Pages 33-38. 2002. PB - PUBLISHER: Bureau Gravimetrique International. Paris, France. 2002. CP - COUNTRY OF PUBLICATION: France PY - PUBLICATION YEAR: 2002 LA - LANGUAGE: English AB - ABSTRACT: We propose the establishment and maintenance of a gravity network in the Caribbean. The project will consist of the following phases: 1. validation of existing gravity data and digital terrain models (DTM's) in this region; 2. establishment of the main (primary) gravity network in the following countries (islands): Jamaica, Cuba, Haiti, Dominican Republic, Puerto Rico, US and British Virgin Islands, French and Holland's Antilles, Aruba, Bonaire and Curacao ("ABC" islands under Dutch administration), Trinidad and Tobago, Northern Venezuela and Northern Colombia, Panama, Costa Rica, Nicaragua, El Salvador, Guatemala, Belize, Honduras and Mexico. In the main gravity network the absolute gravity values shall be determined with FG5 or equivalent instrument; 3. densification of the primary gravity network, thus establishing a secondary gravity network; 4. network adjustment; dissemination of gravity data; 5. network maintenance. Some of the reasons to justify this project are listed below: to fill-up the gap in gravity data between the North and the South Americas; to model the geoid (particularly geoid slopes) in this region; to validate the gravity data from the satellite missions: CHAMP, GRACE, GOCE; to verify (i.e. confirm) the existence of the following microplates: Gonave, Hispaniola, Puerto Rico and Northern Virgin Islands, Colombian, Venezuelan and Panamian within the Caribbean Plate and their behaviour as suggested by recent GPS surveys; to merge gravity data with other types of data, such as: satellite altimetry, seismic, magnetic and electrical to investigate the dynamics and (micro/intra) plate deformation; to validate the use of the gravimeters as the tool for natural hazard mitigation in this tectonically active region (i.e. swelling of the cones of the volcanoes before the eruption, or earthquake prediction); to check (control) the DTM's in this region; to test and model the behaviour of the gravimeters, and in particular: - drift; - sudden changes in atmospheric pressure (tropical storms); - tidal loading (Atlantic Ocean, Pacific and Caribbean Sea); - precipitation (dry versus wet seasons) and related changes in ground water levels; - humidity. DE - DESCRIPTORS: Antilles-; Belize-; Bonaire-; British-Virgin-Islands; Caribbean-region; Central-America; Colombia-; Costa-Rica; Cuba-; Curacao-; Dominican-Republic; El-Salvador; geodesy-; geoid-; gravity-networks; Greater-Antilles; Guatemala-; Haiti-; Hispaniola-; Honduras-; instruments-; Jamaica-; Lesser-Antilles; Mexico-; microplates-; Netherlands-Antilles; Nicaragua-; Panama-; plate-tectonics; programs-; Puerto-Rico; South-America; Trinidad-and-Tobago; Venezuela-; Virgin-Islands; West-Indies CC - CATEGORY CODES: 20-Applied-geophysics DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2005, American Geological Institute. Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique, Vandoeuvre-les-Nancy, France IS - ISSN: 0373-9023 AN - ACCESSION NUMBER: 2005-008006 UD - UPDATE CODE: 200504 Registro 833 de 5614 - GeoRef : 2005/01-2005/07 BK - BOOK TITLE: Three-dimensional structure and kinematics of the Piedras-Girardot Foldbelt in the Northern Andes of Colombia. BA - BOOK AUTHORS: Montes-Camilo Yüklə 20,82 Mb. Dostları ilə paylaş:
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