| Title: | An integrated calcareous microfossil biostratigraphic and carbon isotope stratigraphic framework for the La Luna Formation, western Venezuela |
| Author: | Linda M. de Romero |
| Date Submitted: | 04/29/2002 |
| Address: | CB#3315 Mitchell Hall,
University of North Carolina at Chapel Hill
Chapel Hill
NC
USA
27599-3315
|
| Phone: | (919)968-4874 |
| Email: | deromero@email.unc.edu |
| Co-Authors: | Truskowski, Irene M., Petroleos de Venezuela, TRUSKOWSKIMI@pdvsa.com; Bralower, Timothy J., Univ.of NC, bralower@email.unc.edu; Odreman, Oscar, Univ. de Los Andes, Venezuela; Zachos, James C., Univ. of Calif. at Santa Cruz, jzachos@emerald.ucsc.edu |
| Affiliation: | University of North Carolina at Chapel Hill |
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| Abstract URL: | http://cis.whoi.edu/science/GG/ccod/viewAbstracts.cfm?RefNumber=19725522 |
| Keywords: | biostratigraphy, black shales, calcareous nannofossils, C13/C12, foraminifera, rate of sedimentation |
| Abstract: | The Cretaceous La Luna Formation is the most important petroleum source rock in Venezuela and possibly the most productive in the world. Despite its significance, the biostratigraphy of the formation is not well known. The age has long been in dispute. Most work has previously been done on isolated sections and has not included all members of the formation. Published data are sparse. We have carried out detailed nannofossil and planktic foraminiferal biostratigraphic studies of a cored borehole and five outcrop sections from the Maracaibo Basin of Western Venezuela. Microfossil biostratigraphy combined with carbon-isotope stratigraphy provides a high-resolution stratigraphic framework.
In general planktic foraminifera have fair to good preservation and nannofossils are poorly preserved. Many of the Cenomanian to Campanian planktic foraminiferal marker species are present, permitting the application of a traditional zonal scheme. An informal nannofossil biostratigraphic zonal scheme based primarily on dissolution resistant species has been developed. Integration of these zonal schemes has enabled the correlation of changes in carbon isotope ratios to global C-isotope stratigraphy. The results have been used to estimate temporal variation in sedimentation rates as well as to reconstruct depositional patterns across the Maracaibo Basin. The framework developed allows a revised understanding of temporal and spatial patterns of organic rich sediments in the La Luna Formation throughout the basin. |
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