Display Full Text | Download Full Text
5.35 MB PDF file

Degree

MS, University of Cincinnati, Arts and Sciences : Geology, 2006.

Abstract

Crinoid columnals are a major constituent in the Upper Ordovician fossil assemblage of the Cincinnati Arch Region. Several species of Cincinnatian crinoids are identifiable based on columnal morphology alone. Disarticulated columnals of two crinoids were measured throughout a 68-meter section of the Kope and lower Fairview Formations to examine the relationship between columnal morphology and sea level fluctuations. The columnal diameter of two disparid crinoids increased in the upward shallowing sequence. Detrended Correspondence Analysis axis 1 scores computed using columnal measurements of two crinoids correlated significantly with a proxy for depth. Therefore, crinoid columnals may provide a metric for the study of small-scale sea level fluctuation in a depositional sequence. A larger scale study showed similar morphological shifts in five taxa of crinoids, but to differing degrees. The morphologic shifts in the columnals are likely due to differences in nutrient levels and flow regimes between depths.

Subject Headings

Paleontology

Keywords

Crinoid; Faunal Gradients; Morphology; Cincinnatian; Ordovician; Cincinnaticrinus

Advisor

Dr. David L Meyer

Pages

84p.

Document number: ucin1146843628
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146843628

This ETD has been downloaded 392 times (through March 2013)