Southern Alabama holds one of the world's most complete shallow shelf Cretaceous-Tertiary boundary sections. The boundary is exposed in a sequence of marl-limestone interbeds in a roadcut south-east of Braggs in Lowndes County, Alabama. Benthic foraminifera were extracted in 10cm intervals to obtain a high-resolution record of assemblage succession across this controversial boundary. A local sea level curve was then formulated using previous paleobathymetric foraminiferal assemblage models from the Gulf Coast and the Atlantic Coastal margin. Sea-level fluctuations thus evident have revealed a fourth-order cycle similar to those found by Briskin and Fluegeman (1990) with an average period of around 430 kyr through the Paleocene. This cycle includes a drop from outer slope to middle shelf conditions in the latest Cretaceous and a subsequent increase from inner shelf to outer shelf conditions in the earliest Paleocene. Within this cycle are several fifth-order cycles that are interpreted as having a periodicity of roughly 100 kyr. Sea-level cycles with Milankovitch frequencies occurring on an ice-free Paleocene Earth lend support to the concept of astronomical forcing of climate and thus sea-level. / Department of Geology
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/184488 |
| Date | January 1992 |
| Creators | Brown, Thomas R. |
| Contributors | Ball State University. Dept. of Geology., Fluegeman, Richard H. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | i, 68 leaves : ill. ; 28 cm. |
| Source | Virtual Press |
| Coverage | n-us-al |
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