Controls on the Deposition of Upper Cretaceous Organic Carbon–rich Rocks from Costa Rica to Suriname
Published:January 01, 2003
R. N. Erlich, T. Villamil, J. Keens-Dumas, 2003. "Controls on the Deposition of Upper Cretaceous Organic Carbon–rich Rocks from Costa Rica to Suriname", The Circum-Gulf of Mexico and the Caribbean: Hydrocarbon Habitats, Basin Formation and Plate Tectonics, Claudio Bartolini, Richard T. Buffler, Jon F. Blickwede
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The deposition of organic carbon–rich sediments during the Late Cretaceous in northern South America was controlled by global and local oceanographic, climatic, and tectonic variables. Key in establishing “source rock” depositional systems across the region were eustatic sea-level rise, warming global sea-surface temperatures, the formation of low-latitude saline bottom waters, and a relatively constant supply of fine-grained hemipelagic sediment (mostly derived from the south and east). Specific paleobathymetric conditions enhanced the development of stagnant water masses from the proto-Caribbean plate to Suriname. Organic-matter preservation was aided by the presence of these water masses across the region. Primary productivity was elevated above “normal” marine levels only in the protocentral Caribbean and along the ancestral Costa Rica/Panama island arc, or during seasonal upwelling in northern South America.
Cooler, wetter climatic conditions that began in the late Santonian also were modified by regional and local variables. The development of new intermediate/bottom-water masses, increased polar heat transport caused by improved deep-ocean circulation, and fluctuations in volcanogenic CO2 provided a background effect for local variables such as bathymetry and topography. The development of oxygenated high-latitude water masses provided a means for ventilation of stagnant, low-oxygen bottom waters across northern South America and the central Caribbean. Stronger seasonal upwelling (increased wind stress caused by better polar heat transport, and northward movement of the South American Plate into the zone of northward Ekman transport), more frequent fluvial outflow and deltaic deposition, and the submergence of key paleobathymetric barriers aided ventilation and subsequently diminished organic-matter preservation. Most of these variables had a positive impact on primary productivity and caused rapid changes in the diversity of planktonic foraminifera through the end of the Cretaceous.
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The Circum-Gulf of Mexico and the Caribbean: Hydrocarbon Habitats, Basin Formation and Plate Tectonics
The Circum-Gulf of Mexico and the Caribbean has long been one of the world's most important petroleum provinces, as well as one of the world's most geologically complex regions. These two characteristics have resulted in an extensive amount of ongoing research by both industry and academia. AAPG Memoir 79, The Circum-Gulf of Mexico and the Caribbean, is the first volume in more than a decade to document such a wide range of research on the geology of this vast area. Of the total 44 papers, roughly two-thirds pertain to the Gulf of Mexico, with an emphasis on the Mexican portion of the basin, and to the petroliferous areas of the southern Caribbean, including Colombia, Venezuela, Cuba, and Trinidad and Tobago. The remaining papers relate to the Antilles and Central America, as well as a series of papers that address region-wide topics such as plate tectonic evolution. A significant number of papers were contributed by authors from national oil companies and universities from within the region.