Display Full Text | Download Full Text
18.72 MB PDF file

Degree

MS, University of Cincinnati, Arts & Sciences : Geology, 2003.

Abstract

Centimeter-scale characterization of the mudstone portions of meter-scale cycles within the Alexandria submember of the Upper Ordovician Kope Formation has shown that many epibole intervals exist within these muds that are rich in various fossil Lagerstätten dominated by trilobites and echinoderms. These intervals often persist laterally over distances as large as 50-70 km and are useful as stratigraphic marker horizons. Fossil taphonomy, X-radiography, Thin-section petrography, and SEM imaging have provided sedimentological and mud fabric evidence to suggest that these muds were deposited rapidly as storm-generated density cascades. These cascades travelled downslope as gradient currents, creating Type 3A obrution deposits until a density compensation depth was reached where flocculated muds then spread out along an interface and subsequently settled out to create Type 3B obrution deposits. This model helps to explain the lateral extent of obrution deposition as well as the fossil taphonomy, fabric, and sedimentology of these mudstones.

Keywords

obrution; density cascading; event deposition; fossil Lagerstätten; Cincinnatian

Advisor

DR. CARLTON BRETT

Pages

129p.

Document number: ucin1052758596
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1052758596

This ETD has been downloaded 300 times (through March 2013)