No. Registros Solicitud 1 5614 colombia
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DE - DESCRIPTORS: atmosphere-; benthonic-taxa; biota-; carbon-dioxide; Cenozoic-; climate-change; East-Pacific; ecology-; global-; Holocene-; Invertebrata-; last-glacial-maximum; microfossils-; nitrate-ion; nutrients-; Pacific-Ocean; paleoclimatology-; paleotemperature-; partial-pressure; plankton-; Pleistocene-; productivity-; Protista-; Quaternary-; Radiolaria-; reconstruction-; relative-age; sea-water; sea-surface-temperature; upper-Pleistocene CC - CATEGORY CODES: 07-Oceanography DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 35; illus. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0012-7353 CO - CODEN: DYNAAU AN - ACCESSION NUMBER: 2002-071259 UD - UPDATE CODE: 200222 Registro 522 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Geological hazards. AU - AUTHORS: Shannon-P-J AF - AUTHOR AFFILIATION: Consultant, Houston, TX, United States SO - SOURCE: The Bulletin of the Houston Geological Society. 33; 10, Pages 18-20. 1991. PB - PUBLISHER: Houston Geological Society. Houston, TX, United States. 1991. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1991 LA - LANGUAGE: English DE - DESCRIPTORS: Andes-; Asia-; Colombia-; Eastern-Cordillera; Europe-; field-studies; geologic-hazards; human-activity; Middle-East; South-America; Thrace-; Turkey- CC - CATEGORY CODES: 22-Environmental-geology DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0018-6686 CO - CODEN: BHGLAN AN - ACCESSION NUMBER: 2002-068741 UD - UPDATE CODE: 200221 Registro 523 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Parisite, Muzo District, Colombia. AU - AUTHORS: Cook-Robert-B AF - AUTHOR AFFILIATION: Auburn University, Department of Geology and Geography, Auburn, AL, United States SO - SOURCE: Rocks and Minerals. 75; 4, Pages 250-252. 2000. PB - PUBLISHER: Heldref Publications. Washington, DC, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 LA - LANGUAGE: English DE - DESCRIPTORS: Boyaca-Colombia; carbonates-; collecting-; Colombia-; fluorides-; halides-; mineral-localities; parisite-; siderite-; South-America; synchisite- CC - CATEGORY CODES: 01A-General-mineralogy DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 8; illus. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0035-7529 CO - CODEN: ROCMAR AN - ACCESSION NUMBER: 2002-068539 UD - UPDATE CODE: 200221 Registro 524 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Cooler and drier conditions during the last glacial stage in the Andean tropics inferred from kaolinite isotopic data. AU - AUTHORS: Mora-German; Pratt-Lisa-M AF - AUTHOR AFFILIATION: Indiana University, Department of Geological Sciences, Bloomington, IN, United States BK - BOOK TITLE: In: Geological Society of America, 2000 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 32; 7, Pages 207. 2000. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 CN - CONFERENCE INFORMATION: Geological Society of America, 2000 annual meeting. Reno, NV, United States. Nov. 9-18, 2000. LA - LANGUAGE: English DE - DESCRIPTORS: Andes-; atmospheric-precipitation; authigenic-minerals; Bogota-Basin; clay-minerals; climate-change; Colombia-; D-H; glacial-environment; glacial-geology; hydrogen-; ice-sheets; isotope-ratios; isotopes-; kaolinite-; last-glacial-maximum; meteoric-water; O-18-O-16; oxygen-; paleoclimatology-; paleoenvironment-; paleohydrology-; reconstruction-; sheet-silicates; silicates-; soils-; South-America; stable-isotopes; tropical-environment; volcanic-ash; weathering- CC - CATEGORY CODES: 24-Quaternary-geology; 02D-Isotope-geochemistry 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: 2002-068348 UD - UPDATE CODE: 200221 Registro 525 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: The evolution of Caribbean versus tropical eastern Pacific paleoenvironments of the Isthmus of Panama coincident with its Miocene development. AU - AUTHORS: Collins-Laurel-S AF - AUTHOR AFFILIATION: Florida International University, Department of Earth Sciences, Miami, FL, United States BK - BOOK TITLE: In: Geological Society of America, 2000 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 32; 7, Pages 196. 2000. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 CN - CONFERENCE INFORMATION: Geological Society of America, 2000 annual meeting. Reno, NV, United States. Nov. 9-18, 2000. LA - LANGUAGE: English AB - ABSTRACT: A seaway connected tropical Atlantic and Eastern Pacific waters in the Central American region until approximately 3 Ma. However, sequential changes in marine paleoenvironments on either side of the Isthmus of Panama from its Early Miocene beginnings have implications for the development of the isthmus as a marine environmental barrier much earlier. Benthic foraminiferal assemblages contained in the uplifted Neogene marine sediments exposed on Panama's and Costa Rica's Caribbean and Pacific coasts are used to interpret the paleoenvironments. Biogeographic (Atlantic vs. Pacific) affiliations of the taxa are used to distinguish the timing of the environmental separation caused by the emplacement of the marine barrier. Early Miocene to middle Pliocene faunal assemblages from the Limon, Bocas del Toro and Panama Canal basins on the Caribbean side of the isthmus are compared to those from several Pacific basins of Darien, Eastern Panama. Early Miocene (ca. 17-18 Ma) Caribbean isthmian taxa of Panama and Costa Rica are from lower and middle bathyal paleoenvironments, respectively, and mostly cosmopolitan, suggesting a deep, open interoceanic seaway. By the early middle Miocene ca. 15-16 Ma the Caribbean side had shallowed to upper bathyal depths, but the Pacific side of eastern Panama still showed a middle bathyal connection and taxa were predominantly cosmopolitan without a strong Pacific aspect. Late middle Miocene assemblages of Darien show some endemism of upper to middle bathyal taxa. Water depths shallowed in central to western Panama to inner to middle neritic 12 Ma. Although a bathyal connection persisted in northern Colombia and there was interoceanic exchange of surface water to at least 200 m depth from central to eastern Panama in the late Miocene (ca. 6 Ma), upper bathyal (also neritic) assemblages of Darien had already developed a strong Pacific aspect by ca. 11 Ma, suggesting differentiation of tropical American marine paleoenvironments by that time. DE - DESCRIPTORS: assemblages-; benthonic-taxa; biogeography-; Bocas-del-Toro-Basin; Caribbean-region; Cenozoic-; Central-America; Colombia-; cosmopolitan-taxa; Costa-Rica; Darien-Panama; endemic-taxa; Foraminifera-; Invertebrata-; Limon-Basin; lower-Miocene; microfossils-; Miocene-; Neogene-; paleoenvironment-; Panama-; Panama-Canal-Zone; Protista-; South-America; Tertiary-; tropical-environment; uplifts- CC - CATEGORY CODES: 12-Stratigraphy 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: 2002-068281 UD - UPDATE CODE: 200221 Registro 526 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: New evidence for the earliest stages in the rise of the Isthmus of Panama from Bocas del Toro, Panama. AU - AUTHORS: Coates-Anthony-G; Aubry-Marie-Pierre; Berggren-William-A; Collins-Laurel-S AF - AUTHOR AFFILIATION: Smithsonian Tropical Research Institute, Balboa, Panama BK - BOOK TITLE: In: Geological Society of America, 2000 annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 32; 7, Pages 146. 2000. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 CN - CONFERENCE INFORMATION: Geological Society of America, 2000 annual meeting. Reno, NV, United States. Nov. 9-18, 2000. LA - LANGUAGE: English AB - ABSTRACT: A recently discovered sequence of sedimentary and igneous rocks from Bocas del Toro in western Panama reveals the history of the rise of the Isthmus of Panama in this region from 19.5 Ma to about 8 Ma. The oldest deposit is the Burdigalian Punta Alegre Formation, consisting of muddy ooze and mudstone that contains abundant and diverse nannofossils and planktonic and benthonic foraminifera, yielding an age of 19.5-18 Ma. Deposition took place in lower to middle bathyal water depths. The overlying Valiente Volcanics consists of a heterogeneous suite of interfingering lithofacies characteristic of a tropical volcanic arc. The lithofacies are 1). Columnar basalt and basalt flow breccia; 2) Pyroclastics; 3) Coarse terrestrial, fluviatile and shallow marine volcaniclastics 4) Coral reef lenses with diverse large coral colonies; 5) turbidites and coarse debris flows . Detailed logging of eight sections located around the Valiente Peninsula and Popa and Deer Islands have established that from 18 to 12 Ma a volcanic archipelago emerged in the Bocas del Toro region. Rapid shallowing from lower to upper bathyal depths occurred from Burdigalian (19.5-16.4 Ma) to Langhian (16.4-14.8) time. From Langhian to middle Serravallian (12.2 Ma) no bathymetric change occurred but in the late Serravallian, about 12 Ma, bathyal deposits were replaced by extensive alternating sequences of terrestrial and nearshore marine sediments. The paleobathymetric history of the Limon and Panama Canal Basins follow a similar trajectory. Thus by the end of the Serravallian (11.2 Ma) an extensively emergent archipelago had formed from the Panama Canal Basin westward. Coeval deposits to the east in Darien, eastern Panama, and the Choco, northwestern Colombia, continued to be deposited in bathyal depths indicating a continued oceanic gap between the Central American Volcanic Arc and South America. DE - DESCRIPTORS: algae-; benthonic-taxa; biostratigraphy-; Bocas-del-Toro; Burdigalian-; Cenozoic-; Central-America; clastic-rocks; clastic-sediments; debris-flows; Deer-Island; fluvial-environment; Foraminifera-; igneous-rocks; Invertebrata-; island-arcs; Limon-Basin; lithofacies-; lower-Miocene; marine-environment; mass-movements; microfossils-; Miocene-; mudstone-; nannofossils-; nearshore-environment; Neogene-; ooze-; paleobathymetry-; Panama-; Panama-Canal-Basin; planktonic-taxa; Plantae-; Popa-Island; Protista-; Punta-Alegre-Formation; sedimentary-rocks; sediments-; shallow-water-environment; terrestrial-environment; Tertiary-; turbidite-; Valiente-Peninsula; Valiente-Volcanics CC - CATEGORY CODES: 12-Stratigraphy 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: 2002-068169 UD - UPDATE CODE: 200221 Registro 527 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: A recipe for emeralds. AU - AUTHORS: Stokes-Ronald-B AF - AUTHOR AFFILIATION: Stokes Exploration Management, Vancouver, BC, Canada BK - BOOK TITLE: In: Geological Society of America, Cordilleran Section, 96th annual meeting. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 32; 6, Pages 69. 2000. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 CN - CONFERENCE INFORMATION: Geological Society of America, Cordilleran Section, 96th annual meeting. Vancouver, BC, Canada. April 27-29, 2000. LA - LANGUAGE: English DE - DESCRIPTORS: Colombia-; emerald-; gems-; genesis-; history-; markets-; metamorphic-rocks; mineral-deposits,-genesis; muscovite-schist; price-; ring-silicates; schists-; silicates-; South-America; synthesis- CC - CATEGORY CODES: 28A-Economic-geology,-geology-of-nonmetal-deposits 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: 2002-068121 UD - UPDATE CODE: 200221 Registro 528 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Geology of Colombian emerald deposits. AU - AUTHORS: Montgomery-Joseph-H AF - AUTHOR AFFILIATION: Montgomery Consultants, Vancouver, BC, Canada BK - BOOK TITLE: In: Geological Society of America, Cordilleran Section and associated societies, 96th annual meeting; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: Abstracts with Programs - Geological Society of America. 32; 6, Pages 32. 2000. PB - PUBLISHER: Geological Society of America (GSA). Boulder, CO, United States. 2000. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2000 CN - CONFERENCE INFORMATION: Geological Society of America, Cordilleran Section and associated societies, 96th annual meeting. Vancouver, BC, Canada. April 27 - 29, 2000. LA - LANGUAGE: English DE - DESCRIPTORS: alkaline-earth-metals; beryllium-; black-shale; carbonate-rocks; Cenozoic-; Chivor-Gachala-Deposit; clastic-rocks; Colombia-; dates-; emerald-; Eocene-; gems-; hydrothermal-conditions; K-Ar; leaching-; limestone-; metals-; mineral-deposits,-genesis; Muzo-Coscuez-Deposit; Oligocene-; Paleogene-; ring-silicates; sedimentary-rocks; silicates-; South-America; stratigraphic-boundary; Tertiary- CC - CATEGORY CODES: 28A-Economic-geology,-geology-of-nonmetal-deposits; 01B-Mineralogy-of-silicates 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: 2002-068054 UD - UPDATE CODE: 200221 Registro 529 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Oceanic features influencing small island circulation patterns; case studies. AU - AUTHORS: Watlington-Roy-A; Donoso-Maria-C AF - AUTHOR AFFILIATION: University of the Virgin Islands, Eastern Caribbean Center, Charlotte Amalie, United States Virgin Islands BK - BOOK TITLE: In: Small islands; marine science and sustainable development. BA - BOOK AUTHORS: Maul-George-A (editor) SO - SOURCE: Coastal and Estuarine Studies (Washington). 51; Pages 56-70. 1996. PB - PUBLISHER: American Geophysical Union. Washington, DC, United States. 1996. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1996 CN - CONFERENCE INFORMATION: Meeting on Small island oceanography in relation to sustainable economic development and related coastal area management. MTQ, Martinique, Nov. 8-10, 1993. LA - LANGUAGE: English DE - DESCRIPTORS: Atlantic-Ocean; case-studies; coastal-environment; environmental-management; islands-; ocean-circulation; oil-spills; Pacific-Ocean; Panama-Colombia-Current; pollution-; Rosario-Islands; temperature-; Vesta-Bella-oil-spill CC - CATEGORY CODES: 07-Oceanography; 22-Environmental-geology DT - DOCUMENT TYPE: Serial; Conference-Document BL - BIB LEVEL: Analytic MC - MAP COORDINATES: LAT: N100000; N100000; LONG: W0754000; W0755000. IL - ILLUSTRATION: Refs: 27; illus. incl. sketch map. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0733-9569 AN - ACCESSION NUMBER: 2002-067372 UD - UPDATE CODE: 200221 Registro 530 de 5614 - GeoRef : 2002-2004/12 BK - BOOK TITLE: Mapa geologico de Colombia; Plancha 75, Aguachica, escala 1:100,000; memoria explicativa Translated Title: Geologic map of Colombia; Plate 75, Aquachica, 1:100,000; explanatory notes. BA - BOOK AUTHORS: Torres-Jairo-Clavijo BF - BOOK AUTHOR AFFILIATION: INGEOMINAS, Bucaramaranga, Colombia PB - PUBLISHER: Pages: 48. 1996. CP - COUNTRY OF PUBLICATION: Colombia PY - PUBLICATION YEAR: 1996 LA - LANGUAGE: Spanish DE - DESCRIPTORS: Aquachica-map-sheet; areal-geology; Colombia-; explanatory-text; geologic-maps; maps-; South-America CC - CATEGORY CODES: 14-Geologic-maps DT - DOCUMENT TYPE: Report; Map BL - BIB LEVEL: Monograph MC - MAP COORDINATES: LAT: N072000; N072200; LONG: W0731800; W0732000. MS - MAP SCALE: 1:100,000 MP - MAP TYPE: color-geologic-maps IL - ILLUSTRATION: Refs: 50; illus. incl. 1 table. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. RN - REPORT NUMBER: 75 AV - AVAILABILITY: INGEOMINAS, Bucaramanga, Colombia AN - ACCESSION NUMBER: 2002-066380 UD - UPDATE CODE: 200221 Registro 531 de 5614 - GeoRef : 2002-2004/12 BK - BOOK TITLE: Mapa geologico de Colombia; Plancha 364, Timbio, escala 1:100,000; memoria resumida Translated Title: Geologic map of Colombia; Plate 364, Timbio, 1:100,000; notes. BA - BOOK AUTHORS: Orrego-Abigail (compiler) BF - BOOK AUTHOR AFFILIATION: INGEOMINAS, Cali, Colombia PB - PUBLISHER: Pages: 36. 1993. CP - COUNTRY OF PUBLICATION: Colombia PY - PUBLICATION YEAR: 1993 LA - LANGUAGE: Spanish DE - DESCRIPTORS: areal-geology; Colombia-; explanatory-text; geologic-maps; maps-; South-America; stratigraphic-units; Timbio-map-sheet CC - CATEGORY CODES: 14-Geologic-maps DT - DOCUMENT TYPE: Report; Map BL - BIB LEVEL: Monograph MC - MAP COORDINATES: LAT: N020500; N022500; LONG: W0763500; W0770000. MS - MAP SCALE: 1:100,000 MP - MAP TYPE: color-geologic-maps IL - ILLUSTRATION: Refs: 14; illus. incl. strat. cols. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. RN - REPORT NUMBER: 366 AV - AVAILABILITY: INGEOMINAS, Santafe de Bogata, Colombia AN - ACCESSION NUMBER: 2002-066379 UD - UPDATE CODE: 200221 Registro 532 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Les nouvelles mines d'emeraude de La Pita (Colombie); 2eme partie Translated Title: New emerald mines from La Pita, Colombia; Part 2. AU - AUTHORS: Fritsch-E; Rondeau-B; Notari-F; Michelou-J-C; Devouard-B; Peucat-J-J; Chalain-J-P; Lulzac-Y; de-Naervez-D; Arboleda-C AF - AUTHOR AFFILIATION: Institut des Materiaux Jean Rouxel, Nantes, France SO - SOURCE: Revue de Gemmologie A.F.G.. 144; Pages 13-21. 2002. PB - PUBLISHER: Association Francaise de Gemmologie. Paris, France. 2002. CP - COUNTRY OF PUBLICATION: France PY - PUBLICATION YEAR: 2002 LA - LANGUAGE: French LS - LANGUAGE OF SUMMARY: English DE - DESCRIPTORS: beryl-; Colombia-; crystal-chemistry; crystal-form; emerald-; gems-; inclusions-; La-Pita-Colombia; mines-; ring-silicates; silicates-; South-America; spectra-; veins- CC - CATEGORY CODES: 28A-Economic-geology,-geology-of-nonmetal-deposits DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 12; illus. incl. 3 tables. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique, Vandoeuvre-les-Nancy, France IS - ISSN: 0398-9011 AN - ACCESSION NUMBER: 2002-062683 UD - UPDATE CODE: 200220 Registro 533 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: A new carcineretid crab (upper Turonian, Cretaceous) of Colombia. AU - AUTHORS: Feldmann-Rodney-M; Villamil-Tomas AF - AUTHOR AFFILIATION: Kent State University, Department of Geology, Kent, OH, United States SO - SOURCE: Journal of Paleontology. 76; 4, Pages 718-724. 2002. PB - PUBLISHER: Paleontological Society. Lawrence, KS, United States. 2002. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 2002 LA - LANGUAGE: English AB - ABSTRACT: A single large specimen of carcineretid crab from the Cretaceous Puerto Romero unit of Colombia constitutes the basis for a new species, Ophthalmoplax triambonatus. A re-diagnosis of the Carcineretidae results in the assignment of five genera to the family: Carcineretes Withers, 1922; Branchiocarcinus Vega, Feldmann, and Sour-Tovar, 1995; Mascaranada Vega and Feldmann, 1991; Ophthalmoplax Rathbun, 1935; and Woodbinax Stenzel, 1952. The cross-sectional profile of O. triambonatus suggests that it was a back-burrower, rather than an active swimmer. DE - DESCRIPTORS: Arthropoda-; Carcineretidae-; Colombia-; Cretaceous-; Crustacea-; Invertebrata-; Malacostraca-; Mandibulata-; Mesozoic-; morphology-; new-taxa; Ophthalmoplax-triambonatus; Puerto-Romero-Colombia; South-America; taxonomy-; Turonian-; Upper-Cretaceous CC - CATEGORY CODES: 10-Invertebrate-paleontology DT - DOCUMENT TYPE: Serial BL - BIB LEVEL: Analytic IL - ILLUSTRATION: Refs: 29; illus. incl. sect., strat. col., geol. sketch maps. RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. IS - ISSN: 0022-3360 CO - CODEN: JPALAZ AN - ACCESSION NUMBER: 2002-062326 UD - UPDATE CODE: 200220 Registro 534 de 5614 - GeoRef : 2002-2004/12 TI - TITLE: Carbon isotopic evidence from Paleosols for mixed C (sub 3) / C (sub 4) vegetation in the Bogota Basin, Colombia. AU - AUTHORS: Mora-German; Pratt-Lisa-M AF - AUTHOR AFFILIATION: Indiana University, Department of Geological Sciences, Bloomington IN, United States SO - SOURCE: Quaternary Science Reviews. 21; 8-9, Pages 985-995. 2002. PB - PUBLISHER: Pergamon. Oxford, United Kingdom. 2002. CP - COUNTRY OF PUBLICATION: United-Kingdom PY - PUBLICATION YEAR: 2002 LA - LANGUAGE: English AB - ABSTRACT: Pollen reconstructions in the Bogota basin (Colombia) indicate the expansion of tropical high-altitude grassland (paramo) at the expense of Andean forests during glacial intervals. The carbon isotopic composition (delta (super 13) C) of soil organic matter (SOM) can be a useful indicator of changes in vegetation affecting grasslands because it distinguishes between two groups of grasses (C (sub 3) and C (sub 4) ) adapted to different ecological environments. Values of SOM delta (super 13) C were determined in four weathering profiles containing both modern (Holocene) soils and paleosols formed during the Last Glacial Stage. These profiles are located along an altitudinal transect in the Bogota basin, extending from 2550 to 3100 m. Values of SOM delta (super 13) C in the topsoil horizons reflect those of the native C (sub 3) vegetation that currently dominates the ecosystems in the Colombian Andes. Although C (sub 4) grasses are currently negligible in the basin, elevated SOM delta (super 13) C values indicative of C (sub 4) plants were found in two Holocene soils. Environmental changes or ancient agricultural activities could explain the increased abundance of these plants in the basin during the late Holocene. Isotopic values in the studied paleosols revealed the presence of a mixed C (sub 3) /C (sub 4) vegetation in the basin during the Last Glacial Stage, thus indicating the expansion of C (sub 4) grasses. We hypothesized that lowered pCO (sub 2) and possibly reduced rainfall resulted in the colonization of the tropical Andes by lowland C (sub 4) grasses despite of prevailing cooler temperatures. Yüklə 20,82 Mb. Dostları ilə paylaş:
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