No. Registros Solicitud 1 5614 colombia

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0031-0182

CO - CODEN: PPPYAB

AN - ACCESSION NUMBER: 2003-033365

UD - UPDATE CODE: 200311

Registro 385 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Links between thrust emplacement and quartz cementation in sandstone reservoirs of the Eastern Venezuela Basin and the Eastern Cordillera of Colombia.

AU - AUTHORS: Bordas-Le-Floch-Nathalie; Roure-Francois; Benard-Francine; Toro-Jaime; Lance-Le-Cornec-Sophie; Robion-Philippe

AF - AUTHOR AFFILIATION: Aberdeen University, Geology and Petroleum Geology Department, Aberdeen, United Kingdom

BK - BOOK TITLE: In: Earth system processes; programmes with abstracts.

BA - BOOK AUTHORS: Anonymous

SO - SOURCE: Pages 54. 2001.

PB - PUBLISHER: Geological Society of America and Geological Society of London, International. 2001.

CP - COUNTRY OF PUBLICATION: International

PY - PUBLICATION YEAR: 2001

CN - CONFERENCE INFORMATION: Earth system processes. Edinburgh, United Kingdom. June 24-28, 2001.

LA - LANGUAGE: English

AB - ABSTRACT: Quartz cemented sandstone reservoirs of various ages were studied in six structures in the Eastern Venezuela Basin and the Colombian Llanos. We have combined detailed petrography, fluid inclusions, and thermal modelling to assess the relative timing of quartz cementation and tectonic events. Both ages and temperatures of silicification vary from a structure to another. Nevertheless, in each of these structures, onset of quartz precipitation was contemporaneous with the first compressive phase in the hinterland and with the synflexural series deposition in the foreland. Quartz cementation started when the reservoir still was in the foreland and went on after thrust emplacement. It appears that there has been a temporal control on the onset of quartz cementation, certainly related to the available silica sources. In situ pressure solution of quartz grains and diagenetic transformation in neighbouring shaley levels have been identified as the main local sources of silica. Rapid burial resulting from the syntectonic deposits sedimentation increased pressure solution of quartz grains. Layer parallel shortening induced by Andean compression accentuated this process. Increasing burial also induced clay mineral transformation in shaley formations. An important quantity of silica has thus been released at the beginning of the compressive events, and later on during deformation episodes. By reducing porosity, rapid burial and horizontal compression could also have induced circulation of fluids trapped in the sediments. In addition, topography creation during the orogenic phase may have driven meteoric water circulation forelandward. Therefore, diagenetic reactive elements have possibly been conveyed from the deformed zones in the foothills to the non-deformed areas in the foreland. Quartz cementation probably stopped in response to the combination of several factors resulting in the drying up of the silica source such as hydrocarbon trapping (reservoir oil saturation and precipitation inhibition), tectonic accretion (system closure), erosion (decreasing burial).

DE - DESCRIPTORS: Andes-; cementation-; clastic-rocks; Colombia-; compression-; diagenesis-; Eastern-Cordillera; Eastern-Venezuela; faults-; framework-silicates; Llanos-; orogeny-; petroleum-; pressure-solution; quartz-; reservoir-rocks; sandstone-; sedimentary-rocks; silica-minerals; silicates-; South-America; syntectonic-processes; thrust-faults; traps-; Venezuela-

CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources; 16-Structural-geology

DT - DOCUMENT TYPE: Abstract; Book; Conference-Document

BL - BIB LEVEL: Analytic

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States

AN - ACCESSION NUMBER: 2003-033009

UD - UPDATE CODE: 200311

Registro 386 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: The new accelerograph network for Santa Fe De Bogota, Colombia and implications for microzonation.

AU - AUTHORS: Ojeda-Anibal; Martinez-Samuel; Bermudez-Maria; Atakan-Kuvvet

AF - AUTHOR AFFILIATION: University of Bergen, Institute of Solid Earth Physics, Bergen, Norway

BK - BOOK TITLE: In: SDEE'01; the 10th international conference on Soil dynamics and earthquake engineering.

BA - BOOK AUTHORS: Zerva-A (editor)

SO - SOURCE: Soil Dynamics and Earthquake Engineering (1984). 22; 9-12, Pages 791-797. 2002.

PB - PUBLISHER: CML Publications. Southampton, International. 2002.

CP - COUNTRY OF PUBLICATION: International

PY - PUBLICATION YEAR: 2002

CN - CONFERENCE INFORMATION: 10th international conference on Soil dynamics and earthquake engineering. Philadelphia, PA, United States. Oct. 7-10, 2001.

LA - LANGUAGE: English

AB - ABSTRACT: The new accelerographic network of Santa Fe de Bogota is composed of 29 three-component stations with sensors at the surface and three additional six-component borehole stations with three sensors at the surface and three at depth (115, 126 and 184 m). In total, 32 stations have been operative in the metropolitan area of Bogota since 1999. During this period of time, a significant number of weak motion are recorded and used for a preliminary analysis of local site effects. Using the SH-wave response spectra we verify the behavior of the different seismic zones proposed by the previous microzonation study of the city. A comparison between normalized SH-wave response spectra and the normalized design spectra for each zone clearly depicts that parts of the design spectra should be revised, as well as the boundaries between different zones may require some changes. The spectral amplification levels reach up to a factor of 5. The predominant periods obtained by the amplification spectra in different stations in the city, show variability from 0.3 to 3.0 s. A comparison is also made between the predominant periods obtained using H/V spectral ratios of microtremors and those using weak motion. In general, microtremors tend to predict slightly lower values of dominant periods than those calculated by the weak motion spectra. However, there is a general correlation between the two data sets. Using the data recorded by one of the borehole station, an equivalent linear seismic response analysis was conducted. The modeled and recorded response spectra show similarities in period peaks, however, the modeled soil amplification is underestimated for periods less than 0.8 s. Since the available record is weak motion which represents mostly the linear response of the soils, further analysis is required.

DE - DESCRIPTORS: accelerometers-; attenuation-; Bogota-Colombia; Colombia-; dynamic-properties; earthquakes-; elastic-constants; engineering-properties; geologic-hazards; instruments-; microseisms-; microzonation-; models-; risk-assessment; seismic-networks; seismic-response; seismic-risk; seismic-zoning; shear-modulus; soil-dynamics; soil-mechanics; South-America; spectra-; spectral-analysis; strain-

CC - CATEGORY CODES: 19-Seismology; 30-Engineering-geology

DT - DOCUMENT TYPE: Serial; Conference-Document

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N043800; N043800; LONG: W0740500; W0740500.

IL - ILLUSTRATION: Refs: 5; illus. incl. 3 tables, sketch map.

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0267-7261

CO - CODEN: #03372

AN - ACCESSION NUMBER: 2003-032383

UD - UPDATE CODE: 200311

Registro 387 de 5614 - GeoRef : 2002-2004/12

BK - BOOK TITLE: Catastrophic debris flows transformed from landslides in volcanic terrains; mobility, hazard assessment, and mitigation strategies.

BA - BOOK AUTHORS: Scott-Kevin-M; Macias-Jose-Luis; Naranjo-Jose-Antonio; Rodriguez-Sergio; McGeehin-John-P

BF - BOOK AUTHOR AFFILIATION: U. S. Geological Survey, USA, United States; Universidad Nacional Autonoma de Mexico, Mexico; Servicio National de Geologia y Mineria, Chile

SO - SOURCE: U. S. Geological Survey Professional Paper. 2001.

PB - PUBLISHER: U. S. Geological Survey. Reston, VA, United States. Pages: 59. 2001.

RP - RESEARCH PROGRAM: USGS (Publications of the U. S. Geological Survey)

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 2001

LA - LANGUAGE: English

AB - ABSTRACT: Castastrophic debris flows may begin as landslides and travel 100-200 kilometers from their source areas in volcanic terrains. Many case histories have involved the loss of hundreds and even thousands of lives in the Western Hemisphere, including earthquake-triggered flow in Mexico in 1920 and, most recently, a precipitation-triggered flow in Nicaragua in 1998. The only fail-safe mitigation strategy is land-use planning in response to hazard assessment that minimizes the populations in flow pathways to numbers that can be evacated after event warnings.

DE - DESCRIPTORS: case-studies; collapse-structures; Colombia-; debris-avalanches; debris-flows; earthquakes-; geologic-hazards; gravity-flows; hydrology-; landslides-; mass-movements; mitigation-; mobility-; rainfall-; Rio-Paez-Valley; runoff-; South-America; USGS-; volcanic-features

CC - CATEGORY CODES: 22-Environmental-geology; 23-Geomorphology

DT - DOCUMENT TYPE: Serial; Report

BL - BIB LEVEL: Monograph

IL - ILLUSTRATION: Refs: 184; illus. incl. 9 tables, sketch maps.

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute.

IS - ISSN: 1044-9612

RN - REPORT NUMBER: P 1630

AV - AVAILABILITY: U. S. Geol. Surv., Denver, CO, United States

AN - ACCESSION NUMBER: 2003-031188

UD - UPDATE CODE: 200310

Registro 388 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Applications of automata theory to ray tracing.

AU - AUTHORS: Piedrahita-Carlos; Tygel-Martin; Santos-Lucio-T

AF - AUTHOR AFFILIATION: ICP-ECOPETROL, Bucaramanga, Colombia

BK - BOOK TITLE: In: Society of Exploration Geophysicists, international exposition and 72nd annual meeting; technical program, expanded abstracts with authors' biographies.

BA - BOOK AUTHORS: Anonymous

SO - SOURCE: SEG Annual Meeting Expanded Technical Program Abstracts with Biographies. 72; Pages 2011-2014. 2002.

PB - PUBLISHER: Society of Exploration Geophysicists. Tulsa, OK, United States. 2002.

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 2002

CN - CONFERENCE INFORMATION: Society of Exploration Geophysicists, 72nd annual meeting. Salt Lake City, UT, United States. Oct. 6-11, 2002.

LA - LANGUAGE: English

AB - ABSTRACT: A description is given of the application of symbolic dynamics to ray tracing and how to represent the trajectory in terms of a finite automata (a particular case of a directed graph). With this ideas we extend the continuation method of ray tracing (Keller and Perozzi, 1983) to models of geometric complexity, for example wedges or lenses, of common occurrence in hydrocarbon exploration.

DE - DESCRIPTORS: algorithms-; cellular-automata; data-processing; geometry-; geophysical-methods; non-linear-distortion; numerical-models; ray-tracing; seismic-methods

CC - CATEGORY CODES: 20-Applied-geophysics

DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 9; illus.

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States

IS - ISSN: 1052-3812

AN - ACCESSION NUMBER: 2003-030664

UD - UPDATE CODE: 200310

Registro 389 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Distribution of the river dolphin, tonina Inia geoffrensis, in the Orinoco River basin of Venezuela and Colombia.

AU - AUTHORS: Meade-Robert-H; Koehnken-Lois

AF - AUTHOR AFFILIATION: U. S. Geological Survey, Denver, CO, United States

SO - SOURCE: INTERCIENCIA. 16; 6, Pages 300-312. 1991.

PB - PUBLISHER: Asociacion Interciencia. Caracas, Venezuela. 1991.

RP - RESEARCH PROGRAM: USGSOP (Non-USGS publications with USGS authors)

CP - COUNTRY OF PUBLICATION: Venezuela

PY - PUBLICATION YEAR: 1991

LA - LANGUAGE: English

DE - DESCRIPTORS: Amazon-River; biogeography-; Cetacea-; Chordata-; Colombia-; discharge-; ecology-; Eutheria-; geochemistry-; hydrochemistry-; Inia-; Inia-geoffrensis; living-taxa; Mammalia-; modern-; Orinoco-River-basin; South-America; Tetrapoda-; Theria-; Venezuela-; Vertebrata-

CC - CATEGORY CODES: 11-Vertebrate-paleontology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N020000; N100000; LONG: W0600000; W0750000.

IL - ILLUSTRATION: Refs: 55; illus. incl. 2 tables, geol. sketch maps.

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute.

IS - ISSN: 0378-1844

CO - CODEN: ITRCDB

AN - ACCESSION NUMBER: 2003-029897

UD - UPDATE CODE: 200310

Registro 390 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Geology and reservoir characterisation of the fractured Cimarrona (Maestrichtian) in the Guaduas Field, Magdalena Valley of Colombia; a potential giant oilfield.

AU - AUTHORS: Aguilera-R; Cunningham-R-D

AF - AUTHOR AFFILIATION: Servipetrol, Calgary, AB, Canada

BK - BOOK TITLE: In: Proceedings of the Sixteenth world petroleum congress; Exploration, new petroleum provinces, drilling and production technology, enhanced recovery, deepwater fields.

BA - BOOK AUTHORS: Anonymous

SO - SOURCE: Proceedings - World Petroleum Congress = Actes et Documents - Congres Mondial du Petrole. 16, Vol. 2; Pages 102. 2000.

PB - PUBLISHER: [publisher varies]. [location varies], International. 2000.

CP - COUNTRY OF PUBLICATION: International

PY - PUBLICATION YEAR: 2000

CN - CONFERENCE INFORMATION: Sixteenth world petroleum congress. Calgary, AB, Canada. June 11-15, 2000.

LA - LANGUAGE: English

DE - DESCRIPTORS: Cimarrona-Formation; Colombia-; Cretaceous-; Emeral-Mountain; fractured-materials; fractures-; Guaduas-Field; lithologic-controls; Maestrichtian-; Magdalena-Valley; Mesozoic-; petroleum-engineering; reserves-; reservoir-properties; Senonian-; South-America; 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 2003, American Geological Institute.

IS - ISSN: 0084-2176

IB - ISBN: 0-85293-294-4

CO - CODEN: WPCPAU

AN - ACCESSION NUMBER: 2003-027913

UD - UPDATE CODE: 200310

Registro 391 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: (super 186) Os- (super 187) Os systematics of Gorgona Island komatiites; implications for early growth of the inner core.

AU - AUTHORS: Brandon-Alan-D; Walker-Richard-J; Puchtel-Igor-S; Becker-Harry; Humayun-Munir; Revillon-Sidonie

AF - AUTHOR AFFILIATION: NASA, Johnson Space Center, Houston, TX, United States

SO - SOURCE: Earth and Planetary Science Letters. 206; 3-4, Pages 411-426. 2003.

PB - PUBLISHER: Elsevier. Amsterdam, Netherlands. 2003.

CP - COUNTRY OF PUBLICATION: Netherlands

PY - PUBLICATION YEAR: 2003

LA - LANGUAGE: English

AB - ABSTRACT: The presence of coupled enrichments in (super 186) Os/ (super 188) Os and (super 187) Os/ (super 188) Os in some mantle-derived materials reflects long-term elevation of Pt/Os and Re/Os relative to the primitive upper mantle. New Os data for the 89 Ma Gorgona Island, Colombia komatiites indicate that these lavas are also variably enriched in (super 186) Os and (super 187) Os, with (super 186) Os/ (super 188) Os ranging between 0.1198397+ or -22 and 0.1198470+ or -38, and with gamma (sub Os) correspondingly ranging from +0.15 to +4.4. These data define a linear trend that converges with the previously reported linear trend generated from data for modern Hawaiian picritic lavas and a sample from the ca. 251 Ma Siberian plume, to a common component with a (super 186) Os/ (super 188) Os of approximately 0.119870 and gamma (sub Os) of +17.5. The convergence of these data to this Os isotopic composition may imply a single ubiquitous source in the Earth's interior that mixes with a variety of different mantle compositions distinguished by variations in gamma (sub Os) . The (super 187) Os- and (super 186) Os-enriched component may have been generated via early crystallization of the solid inner core and consequent increases in Pt/Os and Re/Os in the liquid outer core, with time leading to suprachondritic (super 186) Os/ (super 188) Os and gamma (sub Os) in the outer core. The presence of Os from the outer core in certain portions of the mantle would require a mechanism that could transfer Os from the outer core to the lower mantle, and thence to the surface. If this is the process that generated the isotopic enrichments in the mantle sources of these plume-derived systems, then the current understanding of solid metal-liquid metal partitioning of Pt, Re and Os requires that crystallization of the inner core began prior to 3.5 Ga. Thus, the Os isotopic data reported here provide a new source of data to better constrain the timing of inner core formation, complementing magnetic field paleo-intensity measurements as data sources that constrain models based on secular cooling of the Earth.

DE - DESCRIPTORS: Colombia-; core-; Cretaceous-; crust-; enrichment-; geochemical-cycle; geochemistry-; Gorgona-Island; igneous-rocks; inner-core; isotope-ratios; isotopes-; komatiite-; lava-; mantle-; Mesozoic-; metals-; Os-187-Os-186; osmium-; platinum-; platinum-group; plutonic-rocks; radioactive-isotopes; rhenium-; South-America; stable-isotopes; theoretical-models; ultramafics-

CC - CATEGORY CODES: 02D-Isotope-geochemistry; 05A-Igneous-and-metamorphic-petrology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N030000; N030000; LONG: W0781000; W0781000.

IL - ILLUSTRATION: Refs: 60; illus. incl. 2 tables.

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0012-821X

CO - CODEN: EPSLA2

AN - ACCESSION NUMBER: 2003-027460

UD - UPDATE CODE: 200309

Registro 392 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Estimacion de las velocidades de intervalo a traves de la funcion de tiempos de difraccion de la sismica geometrica

Translated Title: Evaluation of interval velocities in a seismic system utilizing the diffraction time function.

AU - AUTHORS: Montes-Vides-Luis-Alfredo

AF - AUTHOR AFFILIATION: Universidad Nacional de Colombia, Departamento de Geociencias, Bogota, Colombia

SO - SOURCE: Geologia Colombiana. 24; Pages 177-182. 1999.

PB - PUBLISHER: Universidad Nacional de Colombia, Facultad de Ciencias, Departamento de Geociencias. Bogota, Colombia. 1999.

CP - COUNTRY OF PUBLICATION: Colombia

PY - PUBLICATION YEAR: 1999

LA - LANGUAGE: Spanish

LS - LANGUAGE OF SUMMARY: English

AB - ABSTRACT: Using the geometrical ray theory and employing the second-order approximation of the traveltimes, a method to determine the interval velocities of a seismic system is presented. Ignoring faults and other complexities, the seismic system is modeled as a stack of isotropic and homogeneous layers separated by arbitrarily-curved smooth interfaces; the velocity and density of these layers may have any values. Measuring the traveltimes of some specially selected reflected rays, recorded in multiple coverage on the upper border of the seismic system, the so called Hamilton's point characteristic for reflected events is determined and in consequence the zero-offset diffraction time function is calculated. The interval velocities are calculated through the downward continuation of the zero-offset diffraction time function applying an iterative process layer by layer. This process is controlled by using a focusing principle.

DE - DESCRIPTORS: arrival-time; diffraction-; earthquakes-; elastic-waves; raypaths-; recurrence-interval; reflection-; refraction-; seismic-migration; seismic-waves; seismic-zoning; time-variations; traveltime-

CC - CATEGORY CODES: 19-Seismology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 7; illus.

RF - REFERENCE SOURCE: GeoRef, Copyright 2003, American Geological Institute.

IS - ISSN: 0072-0992

CO - CODEN: GECBA7

AN - ACCESSION NUMBER: 2003-027131

UD - UPDATE CODE: 200309

Registro 393 de 5614 - GeoRef : 2002-2004/12

TI - TITLE: Evaluacion de la amenaza por deslizamiento en Malaga, Santander, aplicando la metodologia de los conjuntos difusos; un tema de geologia ambiental

Translated Title: Evaluation of landslide threats in Malaga, Santander, utilizing the fuzzy set methodology.

AU - AUTHORS: Portilla-Gamboa-Modesto-Eusebio

AF - AUTHOR AFFILIATION: Universidad Nacional de Colombia, Departamento de Geociencias, Bogota, Colombia

SO - SOURCE: Geologia Colombiana. 24; Pages 159-176. 1999.

PB - PUBLISHER: Universidad Nacional de Colombia, Facultad de Ciencias, Departamento de Geociencias. Bogota, Colombia. 1999.

CP - COUNTRY OF PUBLICATION: Colombia

PY - PUBLICATION YEAR: 1999

LA - LANGUAGE: Spanish

LS - LANGUAGE OF SUMMARY: English

AB - ABSTRACT: Using geological field and photogeological data, the Los Naranjitos landslide in Malaga, eastern Santander province, is taken as an example to develop a methodology to evaluate mass movement hazards, following fuzzy sets theory. The factors involved in the probability of reactivation and the form to evaluate and qualify them trough linguistic variables which are based on human knowledge, are briefly exposed. The geoscientist role, in hazard assessment as a part of risk evaluation is a major parameter in making decisions by national and regional developers and land-use planners. Traditional methodologies give information on probability of hazardous events, without taking into account local geological characteristics. That deficiency is corrected by the geoscientist, applying the fuzzy sets methodology, which well focused gives good results with low uncertainty degree. The results of the proposed case (63%-73% of probability of landslide reactivation) are very important to future investigations. It is necessary to carry out careful studies and formulate similar methodologies applied to vulnerability analysis to get integral risk assessment in mass movements.

DE - DESCRIPTORS: atmospheric-precipitation; Colombia-; deforestation-; erosion-; fuzzy-logic; geologic-hazards; human-activity; landslides-; Malaga-Colombia; mass-movements; mining-; mining-geology; photogeology-; public-awareness; rain-; remote-sensing; risk-assessment; Santander-Colombia; site-exploration; slope-stability; South-America

CC - CATEGORY CODES: 30-Engineering-geology; 22-Environmental-geology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N064000; N064500; LONG: W0723500; W0724500.