Cambrian explosion, Burgess Shale-type, Cambrian Wheeler Formation of Utah, organisms, fossil records
Cambrian Burgess Shale-type (BST) deposits are among the most significant deposits for understanding the “Cambrian explosion” because they contain the fossilized tissues of nonmineralized organisms and provide a substantially different window on the radiation of the Metazoa than is afforded by the more “typical” fossil record of skeletal parts of biomineralized organisms. Despite nearly a century of research, BST deposits remain poorly investigated as sedimentologic entities largely because they comprise fine-grained mudrocks. Here,we describe a new, integrative approach to understanding a single BST deposit, the middle Cambrian Wheeler Formation of Utah, which reveals a dynamic interplay of paleoenvironmental, paleoecologic, and sedimentologic/diagentic factors within a superficially homogeneous lithofacies.This millimeter-scale microstratigraphic and paleontologic approach is augmented by both outcrop and microscopic study.These types of data are applicable to issues of quite different scales, including micron-scale diagenetic processes involved in fossil preservation, organism-environment interactions and paleoecology of the early Metazoa, and regional and global controls on the distribution of BST deposits.
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Gaines, R.R., and Droser, M.L., 2005, New Approaches to Understanding the Mechanics of Burgess Shale-type Deposits: From the Micron Scale to the Global Picture, The Sedimentary Record, v. 3, n. 2, p. 4-8. http://www.sepm.org/pages.aspx?pageid=37