--> Abstract: Processes of Benthic Foraminiferal Fossil Assemblage Formation on the Continental Slope, by P. Loubere; #91004 (1991)

Datapages, Inc.Print this page

Processes of Benthic Foraminiferal Fossil Assemblage Formation on the Continental Slope

LOUBERE, PAUL, Northern Illinois University, DeKalb, IL

Theoretical analysis of benthic foraminiferal fossil assemblage formation shows that the assemblage eventually preserved in the sediments is an integrated result of species' test production rate, microhabitat behavior, and biogeochemical processes that control the

probability of species' test preservation. Further, the detailed analysis of species' abundance profiles in the upper 10-20 cm of slope sediments provides a means of examining species' microhabitats, production rates, and the intensity of taphonomic processes affecting the developing microfossil record. The biogeochemical processes that influence test preservation in slope sediments are controlled by the flux of organic carbon to the sea-bed and the bottom water oxygen concentration. These variables also affect the depth of the biotic habitation zone in the sediments. Therefore, organic carbon flux and bottom water oxygen content should be reflected in benthic foraminiferal fossil assemblages for both ecologic and taphonomic reasons. An integrated study of fossil assemblage generation was conducted on the Gulf of Mexico continental slope using box cores collected along depth transects across the oxygen minimum, and using live and dead assemblage analysis combined with (210)Pb measurements to quantify biotic activity in the sediments and pore water nutrient and metals analysis to quantify biogeochemical processes acting in the sediment habitation zone. The results show that the size of the habitation zone and live standing stock are influenced by organic carbon flux and oxygen supply to the sea-bed. The fossil assemblage is created progressively through the upper 10-20 cm of sediment and biogeochemically driven test destruction (taphonomic process) is important in determining the assemblage that enters the geologic record.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)