Late Cretaceous biostratigraphy of the La Luna Formation, Maracaibo basin
Journal Article
·
· AAPG Bulletin
OSTI ID:421218
Micropaleontological analysis, sedimentological studies, and geochemical data are presented for the Upper Cretaceous {open_quote}black shales{close_quote} of the La Luna Formation of Western Venezuela. The detailed planktonic foraminiferal studies allowed the establishment of the first biozonation, determination of sedimentation rates, and documentation of occurrences of benthic foraminifers for these unusually thick black shales that extend stratigraphically nearly 100 m. Hedbergellids, whiteinellids and Heterohelix characterize the lower part of the La Luna Formation, dated from the late Cenomanian Rotalipora cushmani Zone to middle Turonian Helvetoglobotruncana belvetica Zone. The high productivity of these groups associated with phosphatized fish remains suggest upwelling and a poorly stratified water column. The presence of buliminids and Favreina sp. at some levels, imply disoxic conditions in this anoxic interval. Planktonic foraminifers in the middle and upper parts of the formation range in age from the late Turonian Marginotruncana sigali- Dicarinella primitiva Zone to the early Campanian Globotruncanita elevata Zone. The increase in keeled planktonic foraminifers toward the top of the formation suggest more stratified, oligotrophic surface waters. Benthic foraminifers found at the top are indicative of dysaerobic conditions. This study provides new opportunities for utilizing the petroleum system in the La Luna Formation, arguably the most prolific source rock in northern South America.
- OSTI ID:
- 421218
- Report Number(s):
- CONF-9609255--
- Journal Information:
- AAPG Bulletin, Journal Name: AAPG Bulletin Journal Issue: 8 Vol. 80; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
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Conference
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Sat Aug 01 00:00:00 EDT 1987
· AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)
·
OSTI ID:5906302
Variations in organic facies and sedimentary environments of the La Luna Formation and Machiques Member in the Perija Mountain Range, Venezuela
Conference
·
Sun Jan 31 23:00:00 EST 1993
· AAPG Bulletin (American Association of Petroleum Geologists); (United States)
·
OSTI ID:6108501
Biostratigraphy of a Middle Miocene-Pliocene sequence from Cumarebo area, Falcon State, northwestern Venezuela
Conference
·
Thu Feb 28 23:00:00 EST 1991
· AAPG Bulletin (American Association of Petroleum Geologists); (United States)
·
OSTI ID:5675870