Mechanisms and Rates of Preservation of Organic and Skeletal Remains in Continental Shelf and Slope Environments

Oberlin College, Oberlin OH

Investigators

Abstract

Mechanisms and Rates of Preservation of Organic and Skeletal remains in Continental Shelf and Slope Environments Karla Parsons-Hubbard EAR-9909317 A major impediment in the interpretation of fossil assemblages has been the inadequate understanding of the biases in it caused (a) by the taphonomic alteration of the original assemblage of living organisms and (b) by the time averaging of temporally distinct faunas. To better understand these taphonomic processes experiments were placed in a wide variety of environments of deposition in deep offshore settings in 1993 and 1994. The experiments consist of a variety of potentially preservable organisms such as bivalves, gastropods, urchins, crabs, and plant species. These materials have been allowed to decay on the sea floor since deployment. Collections were made after two years at all sites and the early taphonomic signature was assessed. The present work involves the collection of the experiments at year 8. Preliminary results show that this is a crucial time for the mollusk remains, particularly in waters within the photic zone. Dissolution and degradation by boring organisms have progressed to the point that the results from this work may be able to set the "life span" of mollusk remains in shallow waters at somewhere between 7 and 10 years and in deeper waters we may find much slower rates of degradation.