No. Registros Solicitud 1 5614 colombia

CC - CATEGORY CODES: 28A-Economic-geology,-geology-of-nonmetal-deposits; 01B-Mineralogy-of-silicates

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

NN - ANNOTATION: IGCP Project No. 342.

IL - ILLUSTRATION: Refs: 50; illus. incl. 3 tables.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0020-6814

CO - CODEN: IGREAP

AN - ACCESSION NUMBER: 1998-021657

UD - UPDATE CODE: 199809

Registro 5517 de 5614 - GeoRef 1997-2001

TI - TITLE: Fluid composition, delta D of channel H (sub 2) O, and delta (super 18) O of lattice oxygen in beryls; genetic implications for Brazilian, Colombian, and Afghanistani emerald deposits.

AU - AUTHORS: Giuliani-G; France-Lanord-C; Zimmermann-J-L; Cheilletz-A; Arboleda-C; Charoy-B; Coget-P; Fontan-F; Giard-D

AF - AUTHOR AFFILIATION: ORSTOM, Institut Francais de la Recherche Scientifique pour le Developpement en Cooperation, Paris, France

SO - SOURCE: International Geology Review. 39; 5, Pages 400-424. 1997.

PB - PUBLISHER: Winston & Son. Silver Spring, MD, United States. 1997.

RP - RESEARCH PROGRAM: IGCP (International Geological Correlation Programme)

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

AB - ABSTRACT: The fluid composition, delta D of channel H (sub 2) O, and delta (super 18) O of lattice oxygen have been determined in beryl and emerald from a variety of geological environments and used to constrain the origin of the parental fluids from which beryl has grown. Step-heating analyses performed by quadrupolar mass spectrometry were used to quantify the composition of the fluid phases in beryl from granitic pegmatites and greisens and emerald from Brazil, Colombia, and Afghanistan. An important conclusion is that beryl and emerald have a similar fluid composition, with concentrations of H (sub 2) O being greater than 90% of the total water in the mineral irrespective of the age of formation (2.0 Ga to 32 Ma) and tectonic settings. However, the Brazilian Santa Terezinha shear-zone emerald deposit contains abundant CO (sub 2) , up to 13 wt% of the total fluid. A second conclusion is that the channel H (sub 2) O content for some Brazilian emeralds is higher than the range defined for beryl in the literature, especially for those related to the shear-zone type (2.99 < H (sub 2) O < 3.16 wt%) and the pegmatite type from the Pombos, Pela Ema, and Pirenopolis deposits (2.78

DE - DESCRIPTORS: Afghanistan-; Asia-; beryl-; Brazil-; Colombia-; crystal-structure; D-H; deuterium-; emerald-; fluid-inclusions; gems-; granites-; hydrogen-; IGCP-; igneous-rocks; inclusions-; Indian-Peninsula; isotope-ratios; isotopes-; magmatism-; metamorphism-; mineral-deposits,-genesis; native-elements; O-18-O-16; ore-forming-fluids; oxygen-; pegmatite-; plutonic-rocks; ring-silicates; sampling-; silicates-; South-America; stable-isotopes

CC - CATEGORY CODES: 28A-Economic-geology,-geology-of-nonmetal-deposits; 02D-Isotope-geochemistry

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

NN - ANNOTATION: IGCP Project No. 342.

IL - ILLUSTRATION: Refs: 74; illus. incl. 3 tables.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0020-6814

CO - CODEN: IGREAP

AN - ACCESSION NUMBER: 1998-021656

UD - UPDATE CODE: 199809

Registro 5518 de 5614 - GeoRef 1997-2001

TI - TITLE: Gold mining and exploration in South America; an overview.

AU - AUTHORS: Harris-L

BK - BOOK TITLE: In: World gold '97.

BA - BOOK AUTHORS: Tyrwhitt-David (chairperson)

SO - SOURCE: Publication Series - Australasian Institute of Mining and Metallurgy. 2/97; Pages 3-10. 1997.

PB - PUBLISHER: Australasian Institute of Mining and Metallurgy. Parkville, Victoria, Australia. 1997.

CP - COUNTRY OF PUBLICATION: Australia

PY - PUBLICATION YEAR: 1997

CN - CONFERENCE INFORMATION: World gold '97. SGP, Singapore, Sept. 1-3, 1997.

LA - LANGUAGE: English

DE - DESCRIPTORS: Argentina-; Bolivia-; Brazil-; case-studies; Chile-; Colombia-; economics-; Ecuador-; French-Guiana; future-; gold-ores; Guyana-; history-; metal-ores; mineral-exploration; mining-; mining-geology; Peru-; production-; regulations-; South-America; tonnage-; Venezuela-

CC - CATEGORY CODES: 27A-Economic-geology,-geology-of-ore-deposits

DT - DOCUMENT TYPE: Serial; Conference-Document

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: 6 tables.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 1324-6240

IB - ISBN: 1-875-77645-1

CO - CODEN: #03621

AN - ACCESSION NUMBER: 1998-020553

UD - UPDATE CODE: 199808

Registro 5519 de 5614 - GeoRef 1997-2001

TI - TITLE: Propagation efficiency of long-period Lg waves in the South American continent.

AU - AUTHORS: Rial-J-A; Ritzwoller-M-H

AF - AUTHOR AFFILIATION: University of North Carolina, Geology Department, Chapel Hill, NC, United States

SO - SOURCE: Geophysical Journal International. 131; 2, Pages 401-408. 1997.

PB - PUBLISHER: Blackwell Scientific. Oxford, United Kingdom. 1997.

CP - COUNTRY OF PUBLICATION: United-Kingdom

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

AB - ABSTRACT: We investigate the propagation-efficiency characteristics of long-period (3-12s) Lg waves in continental South America as recorded in the last few years on stations of the GTSN, IRIS/USGS, IRIS/IDA and GEOSCOPE networks. This paper reports the results of a first look at the available Lg data for events with M (sub s) >5.0 from 1990 to 1995. In this period seven main seismic events and aftershocks along the length of the Andes produced a total of 29 usable paths from which preliminary results indicate that (1) long-period Lg waves are unusually prominent in seismograms of continental paths covering the shield areas of South America, and are clearly observed on broad-band instruments at epicentral distances exceeding 3500 km, (2) Lg propagation is substantially attenuated (weak or absent) for paths along the strike of the Andes and along the three active volcanic chains of Chile, Peru and Colombia, (3) away from the active volcanoes, the data show Lg propagating more efficiently across than along the strike of the Andes, and (4) in general, the ratio of the transverse to the vertical components of the Lg phase decreases with decreasing propagation efficiency. These first results also raise a number of exciting questions regarding the exploration of the crustal waveguide in South America, such as the potential for Lg-based tomography to detect a postulated fossil plume in southeastern Brazil, or how the propagation efficiency of high-frequency Lg in volcanically active areas may be used to detect magma chambers. Consequently, we intend to carry out a systematic study of Lg in the continent as part of the ongoing Surface-wave Inversion for the South American Lithosphere (SISAL) project, a collaborative effort (Vdovin et al. 1996) to determine the crustal and lithospheric structure of the South American Plate from measurements of surface-wave dispersion in the period range 2-200 s.

DE - DESCRIPTORS: crust-; elastic-waves; interpretation-; Lg-waves; lithosphere-; plate-tectonics; propagation-; seismic-waves; South-America; surface-waves; velocity-structure

CC - CATEGORY CODES: 18-Solid-earth-geophysics

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 20; illus.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0956-540X

AN - ACCESSION NUMBER: 1998-009305

UD - UPDATE CODE: 199804

Registro 5520 de 5614 - GeoRef 1997-2001

BK - BOOK TITLE: Rapid simulation of multiphase flow in heterogeneous reservoirs using 3D streamlines.

BA - BOOK AUTHORS: Peddibhotla-Sriram

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1997

DG - DEGREE GRANTED: Doctoral

DI - DEGREE GRANTING INSTITUTION: Texas A&M University. College Station, TX, United States. Pages: 122. 1997.

LA - LANGUAGE: English

DE - DESCRIPTORS: algorithms-; characterization-; Colombia-; cores-; drilling-; finite-difference-analysis; geostatistics-; heterogeneous-materials; La-Cira-Field; North-Robertson-Unit; oil-and-gas-fields; oil-wells; patterns-; petroleum-; petroleum-engineering; prediction-; reservoir-properties; reservoir-rocks; saturation-; simulation-; South-America; statistical-analysis; Texas-; three-dimensional-models; United-States; velocity-; waterflooding-; well-logs; wells-; West-Texas

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

DT - DOCUMENT TYPE: Thesis-or-Dissertation

BL - BIB LEVEL: Monograph

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

AV - AVAILABILITY: University Microfilms, Ann Arbor, MI, United States

AN - ACCESSION NUMBER: 1998-004118

UD - UPDATE CODE: 199802

Registro 5521 de 5614 - GeoRef 1997-2001

TI - TITLE: A new analysis of the great 1970 Colombia earthquake and its isotropic component.

AU - AUTHORS: Russakoff-Daniel; Ekstrom-Goran; Tromp-Jeroen

AF - AUTHOR AFFILIATION: Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA, United States

SO - SOURCE: Journal of Geophysical Research, B, Solid Earth and Planets. 102; 9, Pages 20,423-20,434. 1997.

PB - PUBLISHER: American Geophysical Union. Washington, DC, United States. 1997.

CP - COUNTRY OF PUBLICATION: United-States

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

DE - DESCRIPTORS: Colombia-; Colombia-earthquake-1970; coupling-; earthquakes-; focal-mechanism; isotropy-; low-frequency-analysis; magnitude-; revision-; seismic-moment; South-America; spectral-analysis; wave-splitting

CC - CATEGORY CODES: 19-Seismology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 29; illus. incl. 2 tables, sketch map.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0885-3401

AN - ACCESSION NUMBER: 1998-004009

UD - UPDATE CODE: 199802

Registro 5522 de 5614 - GeoRef 1997-2001

TI - TITLE: Dados geocronologicos Rb-Sr para rochas gnaissicas e tonaliticas dos Andes colombianos

Translated Title: Rb/ Sr geochronologic data for gneissic and tonalitic rocks from the Colombian Andes.

AU - AUTHORS: Ordonez-Oswaldo-C; Pimentel-Marcio-M; Viana-Maria-das-Gracas

AF - AUTHOR AFFILIATION: Universidade de Brasilia, Instituto de Geociencias, Brasilia, Brazil

SO - SOURCE: Anais da Academia Brasileira de Ciencias. 69; 2, Pages 290. 1997.

PB - PUBLISHER: Academia Brasileira de Ciencias. Rio de Janeiro, Brazil. 1997.

CP - COUNTRY OF PUBLICATION: Brazil

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: Portuguese

DE - DESCRIPTORS: absolute-age; Andes-; Antioqueno-Batholith; Colombia-; Cretaceous-; dates-; diorites-; El-Vapor-Mylonites; gneisses-; igneous-rocks; Mesozoic-; metamorphic-rocks; overprinting-; Paleozoic-; Permian-; plutonic-rocks; Precambrian-; Proterozoic-; Puqui-Complex; Rb-Sr; South-America; tonalite-; upper-Precambrian; whole-rock

CC - CATEGORY CODES: 03-Geochronology; 05A-Igneous-and-metamorphic-petrology

DT - DOCUMENT TYPE: Abstract; Serial

BL - BIB LEVEL: Analytic

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0001-3765

CO - CODEN: AABCAD

AN - ACCESSION NUMBER: 1998-001391

UD - UPDATE CODE: 199801

Registro 5523 de 5614 - GeoRef 1997-2001

TI - TITLE: Geochronology and Nd isotopic data of Grenville-age rocks in the Colombian Andes; new constraints for late Proterozoic-early Paleozoic paleocontinental reconstructions of the Americas.

AU - AUTHORS: Restrepo-Pace-Pedro-A; Ruiz-Joaquin; Gehrels-George-E; Cosca-Michael

AF - AUTHOR AFFILIATION: University of Arizona, Department of Geosciences, Tucson, AZ, United States

SO - SOURCE: Earth and Planetary Science Letters. 150; 3-4, Pages 427-441. 1997.

PB - PUBLISHER: Elsevier. Amsterdam, Netherlands. 1997.

CP - COUNTRY OF PUBLICATION: Netherlands

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

AB - ABSTRACT: New U-Pb zircon crystallization ages and (super 40) Ar/ (super 39) Ar cooling ages from the Colombian Andes confirm the existence of rocks metamorphosed during the Orinoquian Orogenic Event (ca. 1.0 Ga) of northern South America. epsilon (sub Nd) (t = 1.1 Ga) for these rocks range from -3.9 to +0.91, which is interpreted as a mixture of Late Archean-Early Proterozoic crust with juvenile material produced during the 1.1 Ga orogenic event. The Colombian Grenville age rocks are part of a much longer metamorphic pericratonal belt, sporadically exposed along the Andes, in western-central Peru, southern Bolivia and northern Argentina. In addition, Nd model (T (sub DM) ) ages for the Colombian rocks range from 1.9 to 1.45 Ga, similar to those obtained in the Grenville Province of the eastern U.S. and in the Mexican basement, placing constraints on Late Proterozoic-Early Paleozoic paleocontinental reconstructions.

DE - DESCRIPTORS: absolute-age; Andes-; Ar-Ar; Colombia-; Colombian-Andes; continental-drift; cooling-; crust-; dates-; Garzon-Massif; gneisses-; granulites-; Grenvillian-Orogeny; isotope-ratios; isotopes-; lower-Paleozoic; metals-; metamorphic-rocks; metamorphism-; Nd-144-Nd-143; neodymium-; Neoproterozoic-; nesosilicates-; Northern-Andes; orogeny-; orthosilicates-; paleogeography-; Paleozoic-; Precambrian-; Proterozoic-; rare-earths; reconstruction-; Santander-Massif; Sierra-Nevada-de-Santa-Marta; silicates-; South-America; stable-isotopes; U-Pb; upper-Precambrian; whole-rock; zircon-

CC - CATEGORY CODES: 03-Geochronology; 02D-Isotope-geochemistry; 12-Stratigraphy

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

MC - MAP COORDINATES: LAT: N010000; N020000; LONG: W0750000; W0750000.

LAT: N080000; N080000; LONG: W0730000; W0730000.

LAT: N100000; N110000; LONG: W0730000; W0740000.

IL - ILLUSTRATION: Refs: 72; illus. incl. 3 tables, geol. sketch maps.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0012-821X

CO - CODEN: EPSLA2

AN - ACCESSION NUMBER: 1997-076867

UD - UPDATE CODE: 199724

Registro 5524 de 5614 - GeoRef 1997-2001

TI - TITLE: Hydrological landslide triggering in ash-covered slopes of Manizales (Colombia).

AU - AUTHORS: Terlien-Mark-T-J

AF - AUTHOR AFFILIATION: International Institute for Aerospace Survey and Earth Sciences, Delft, Netherlands

SO - SOURCE: Geomorphology. 20; 1-2, Pages 165-175. 1997.

PB - PUBLISHER: Elsevier. Amsterdam, Netherlands. 1997.

CP - COUNTRY OF PUBLICATION: Netherlands

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

AB - ABSTRACT: A study on hydrological landslide triggering was carried out on ash-covered slopes near the city of Manizales (Colombia). The saturated hydraulic conductivity of the different soil types and the pressure head fluctuations in relation to rainfall were determined in order to detect saturated zones in the soil profile which form preferential zones for the development of slip surfaces of landslides. Tensiometer measurements revealed saturation in the topsoil as a result of infiltration of rainfall, in the ashes as a result of a perched water table and at the soil-bedrock contact as a result of a groundwater table. The location of the saturated zones in the soil profile proved to be in accordance with the location of slip surfaces observed in the field. Three landslides were selected for back analysis to establish the pressure heads that could have triggered these landslides. The pressure heads obtained by back analysis were compared with the measured pressure head ranges. The back-calculated pressure heads proved to support the conclusions of the hydrological study.

DE - DESCRIPTORS: aquifers-; causes-; Colombia-; geologic-hazards; ground-water; hydraulic-conductivity; hydrology-; infiltration-; landslides-; Manizales-Colombia; mass-movements; perched-aquifers; pore-pressure; pore-water; pressure-; rainfall-; saturation-; slopes-; South-America; stability-; tensiometers-; water-regimes; water-table

CC - CATEGORY CODES: 23-Geomorphology; 21-Hydrogeology

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 16; illus. incl. 4 tables, sketch maps.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

IS - ISSN: 0169-555X

CO - CODEN: #53194

AN - ACCESSION NUMBER: 1997-072055

UD - UPDATE CODE: 199724

Registro 5525 de 5614 - GeoRef 1997-2001

TI - TITLE: Techniques and methodology used in a mineralogical and osmium isotope study of platinum group minerals from alluvial deposits in Colombia, California, Oregon and Alaska.

AU - AUTHORS: Lyon-I-C; Tamana-H; Vaughan-D-J; Criddle-A-J; Saxton-J-M; van-Lierde-P

AF - AUTHOR AFFILIATION: University of Manchester, Department of Earth Sciences, Manchester, United Kingdom

SO - SOURCE: Mineralogical Magazine. 61; 3, Pages 367-375. 1997.

PB - PUBLISHER: Mineralogical Society. London, United Kingdom. 1997.

CP - COUNTRY OF PUBLICATION: United-Kingdom

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

AB - ABSTRACT: Platinum-group minerals (PGM) from placer deposits in Colombia, California, Oregon and Alaska were investigated with the electron microprobe, proton microprobe (mu -PIXE) and ion probe to analyse their major and trace element contents and (super 187) Os/ (super 186) Os isotopic ratios. Most of the grains in the samples investigated proved to be essentially homogeneous alloys of Pt-Fe and Os-Ir-Ru although a few of them contained inclusions of other PGM such as cooperite and laurite. Detailed analyses were undertaken on the Os-Ir-Ru alloy phases. The (super 187) Os/ (super 186) Os isotope ratios fell into a range from 1.005 to 1.156 and are consistent with data published on PGM from other placer deposits from these regions. The ratios, together with the trace element data (and in particular the low rhenium content) determined by ion probe and mu -PIXE, indicate that crustal osmium was not incorporated in the grains and that no significant evolution of the (super 187) Os/ (super 186) Os ratios occurred during their history. These data, along with mineralogical and textural evidence, are consistent with a mantle origin for the grains through ultramafic intrusions, although the data do not entirely rule out alternative interpretations.

DE - DESCRIPTORS: Alaska-; alluvial-fans; California-; Colombia-; electron-probe-data; geochemistry-; isotope-ratios; isotopes-; metals-; mineralization-; Oregon-; Os-187-Os-186; osmium-; platinum-group; platinum-minerals; radioactive-isotopes; South-America; stable-isotopes; United-States

CC - CATEGORY CODES: 01A-General-mineralogy; 02D-Isotope-geochemistry

DT - DOCUMENT TYPE: Serial

BL - BIB LEVEL: Analytic

IL - ILLUSTRATION: Refs: 24; 3 tables.

RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute.

IS - ISSN: 0026-461X

AN - ACCESSION NUMBER: 1997-070776

UD - UPDATE CODE: 199723

Registro 5526 de 5614 - GeoRef 1997-2001

TI - TITLE: A reassessment of the deep Fiji earthquake of 26 May 1932.

AU - AUTHORS: Okal-Emile-A

AF - AUTHOR AFFILIATION: Northwestern University, Department of Geological Sciences, Evanston, IL, United States

SO - SOURCE: Tectonophysics. 275; 4, Pages 313-329. 1997.

PB - PUBLISHER: Elsevier. Amsterdam, Netherlands. 1997.

CP - COUNTRY OF PUBLICATION: Netherlands

PY - PUBLICATION YEAR: 1997

LA - LANGUAGE: English

AB - ABSTRACT: The 1932 deep Fiji earthquake is studied from the point of view of comparing it to the recent large events in the transition zone. Spectral analysis and body-wave modeling suggest a moment of dyn cm (within a multiplicative or divisive factor of 1.5), which makes it comparable to, but not significantly larger than, the great 1994 earthquake, 770 km to the north. Its seismic moment remains well below that of the largest deep shocks (1994 in Bolivia or 1970 in Colombia). Relocation efforts show that the earthquake took place on the front edge of the Wadati-Benioff Zone, in an area where the latter features a complex geometry involving significant warping. The mechanism of the earthquake involves down-dip compression and can be readily explained in terms of the prevailing large-scale stresses in the slabs.