Date of Degree
2006
Document Type
thesis
Degree Name
MS (Master of Science)
Department
Geoscience
First Advisor
Jonathan M. Adrain
Abstract
Previously unreported silicified trilobite faunas occur in a narrow stratigraphic interval of the Upper Cambrian (Sunwaptan) St. Charles Formation in the Bear River Range of southeastern Idaho. The faunas occur in four closely spaced rudstones and trilobite packstones indicating deposition in a shallow subtidal setting above storm wave base. At least 23 species are represented, included two undescribed genera and several undescribed species. The faunas are notable for their high trilobite abundance and pervasive silicification. Most coeval faunas have been described on the basis of small numbers of "crack-out" specimens, and the new material reveals many details of anatomy, including knowledge of most exoskeletal sclerites. The four trilobite-yielding beds contain markedly different taxon-abundance profiles, yet most species are shared between them. This suggests multiple, taphonomically-controlled samples of a similar underlying distribution, though true ecological variation cannot be discounted.
Pages
ix, 236
Bibliography
221-236
Copyright
Copyright 2006 Thomas Arthur Hegna
Recommended Citation
Hegna, Thomas Arthur. "Systematics of late Cambrian (Sunwaptian) trilobites from the St. Charles Formation, southeastern Idaho." thesis, University of Iowa, 2006.
http://ir.uiowa.edu/etd/45.