Facies and sedimentary environments of the cretaceous La Luna Formation in San Pedro Del Rio section, Venezuelan Andes: A multidisciplinary study

Conference · Sun Jan 31 23:00:00 EST 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6064898

Boesi, H T.R.; Lorente, M A; Mompart, L; Murat, B; Testamarck, ^[1]; Facon, R ^[2]

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1. Maraven S.A., Caracas (Venezuela)
2. Universidad Central de Venezuela, Caracas (Venezuela)

Vertical variations in facies and sedimentary environments in an outcrop of the La Luna Formation in the Venezuela Andes were evaluated with an integrated study of sedimentology, micropaleontology, palynology, visual kerogen, organic geochemistry and field geology. Up to now, the La Luna Formation, main hydrocarbon source rock in the Maracaibo Basin, has been considered for calculations of oil generation as an homogeneous interval with similar properties across the basin. However, this study reveals important vertical variations in organic facies and sedimentary environments. The microfacies range from almost pure carbonate (recrystallized) mudstone to almost pure shale, with a varying organic content. An overall upward change from oxic to anoxic environments can be recognized, culminating in a chert-rich interval (Ftanita de Tachira Member). The total organic carbon content is high throughout, with the exception of low to moderate values in the chert. The organic matter is mature to postmature. Phosphatic intervals are also developed, supporting a model of platform-edge upwelling and high organic productivity. The presence of rare volcanic grains suggests comtemporaneous volcanic activity within adjacent areas (Colombian Andes ).

• OSTI ID: 6064898
• Report Number(s): CONF-930306--
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:2; ISSN 0149-1423; ISSN AABUD2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ANDES
CHEMISTRY
CRETACEOUS PERIOD
DEVELOPING COUNTRIES
EVALUATION
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGY
GEOMORPHOLOGY
HYDROCARBONS
LATIN AMERICA
MESOZOIC ERA
MINERAL RESOURCES
MOUNTAINS
OIL YIELDS
ORGANIC COMPOUNDS
PALEONTOLOGY
PALYNOLOGY
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
RESOURCE ASSESSMENT
RESOURCES
SEDIMENTATION
SOURCE ROCKS
SOUTH AMERICA
VENEZUELA
YIELDS