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A foraminiferal analysis of the recently completed Continental Offshore Stratigraphic Test (COST) GE-1 well reveals that ~1,000 m of Cenozoic, ~700 m of Upper Cretaceous, and ~1,600 m of Lower Cretaceous sedimentary rocks lie above Devonian metamorphic basement in this part of the Southeast Georgia embayment. Seven regional hiatuses interrupt the depositional record and correspond to times of low global sea level. The hiatuses are between Albian and Turonian rocks; upper Maestrichtian and upper Paleocene; upper Paleocene and lower Eocene; upper Eocene and lower Oligocene; middle Oligocene and middle Miocene; middle Miocene and upper Pliocene; and upper Pliocene and lower Pleistocene. The depositional environments represented in the GE-1 well range from terrestrial nonfoss liferous biotopes to ocean depths equivalent to those of a modern continental slope. Most of the Cenozoic and Upper Cretaceous rocks accumulated in continental-shelf biotopes, but the Lower Cretaceous rocks are largely nonmarine and marginal-marine deposits. The sequence of paleo-environments can be correlated with the supercycles of global sea-level change outlined by P. Vail et al. Sediment-accumulation rates were highest (5.0 to 6.4 cm/1,000 years) during the Albian through Santonian interval, the middle and late Eocene, and the middle Miocene. Lowest rates (1.3 to 2.5 cm/1,000 years) prevailed during the Campanian and Maestrichtian, the early and middle Oligocene, and the Pleistocene. Subsidence calculations reveal that Cretaceous subsidence was more rapid than that of the Cenozoic, hat most of the major paleobathymetric changes were caused by eustatic sea-level fluctuations, and that subsidence rate of the embayment was sensitive to sediment loading and unloading.
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