Late Cretaceous source rocks of a section in the Eastern Venezuelan Basin

Conference · Mon Feb 01 04:00:00 EST 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5941194

Truskowski, I I ^[1]

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1. Intevep S.A., Caracas (Venezuela)

Micropaleontological and geochemical studies of Querecual and San Antonio formations were carried on a section (Cerro Negro) of the Serrania del Interior, in order to establish the imprint of the late Cretaceous [open quotes]Oceanic Anoxic Events[close quotes] (OAE), mentioned by numerous authors. For this purpose, the distribution patterns of microfossil assemblages, variations of organic matter content and, V/Ni ratios have been taken into account to recognize anoxic conditions. This stratigraphic section is characterized by the following: [open quotes]Anaerobic[close quotes] bottom conditions with oxigenated surface waters, indicated by the presence of a well-developed planktonic forms and virtually no benthic foraminifera. These conditions fluctuated along the section, prevailing at its base. Dysaerobic bottom conditions indicated by a low-diversity benthic foraminifera and, a well oxigenated surface waters suggested by high concentration of planktonic biota (foraminifer, radiolaria, and nannoplankton). An increase of organic matter content (TOC: 5-6%) and V/Ni ratios (3.7-4.2) are related to the [open quotes]anaerobic[close quotes] levels. Marine sediments of Brazilian continental margin display similar characteristics, which indicate that deposition of anoxic sediments was extended to the North of South America.

• OSTI ID: 5941194
• Report Number(s): CONF-930306--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 77:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ANIMALS
ANOXIA
CHEMISTRY
CRETACEOUS PERIOD
DEPOSITION
DEVELOPING COUNTRIES
DISTRIBUTION
FORAMINIFERA
FOSSILS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
INVERTEBRATES
LATIN AMERICA
MATTER
MESOZOIC ERA
MICROORGANISMS
ORGANIC MATTER
PALEONTOLOGY
PROTOZOA
SARCODINA
SEAS
SEDIMENTARY BASINS
SEDIMENTS
SOURCE ROCKS
SOUTH AMERICA
SURFACE WATERS
VENEZUELA