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The University of Tennessee

Earth and Planetary Sciences

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Gray, Tennessee, Fossil Site

The Gray, Tennessee, Fossil Site, Washington County, Tennessee, was accidentally discovered in spring of 2000 during construction activities attempting to improve Tennessee Route 75 south of its intersection with I-181 at Gray. The locality is near the SW corner of the Boone Dam 198-NW Topographic quadrangle (36° 23' 11"-12" N; 82° 29' 52"-54" W; elevation 490-510 m). The fossil site is one of only several major finds of Miocene-Pliocene (?) vertebrate remains in North America east of the Mississippi River, and contains a rich assemblage of large vertebrate fossils (Hemphillan Land Mammal Age) as well as an excellent record of plant macrofossils (e.g., leaves, seeds, twigs) and microfossils (e.g., spores, pollen). The major sedimentary unit containing the fossils is a thick (40 m+) deposit of finely graded and laminated organic-rich sediments and is overlain by 5-50 m of chert-rich regolith (alluvium, slopewash, and colluvium). Although the putative environment of clay deposition was a deep, semicircular sinkhole (cenote? sótano?), the extant topography is a hilltop, demonstrating significant inversion of relief since clay deposition and emplacement of the overlying chert-rich regolith. Publication of my research findings and the results of theses research of others will shed light on the geomorphic history of this part of the Appalachian Great Valley. For example, quantification of the averaged rates of differential erosion and inversion of relief will give us the first numerically modelled rates of lowering of carbonate valleys from earth-surface evidence. And, is the Gray, Tennessee, Fossil Site a population of one, or, do other similar regolith deposits exist?

Trackhoe trench for paleomagnetic and pollen sampling projects, Gray, Tennesee, Fossil Site, Washington county


G. Michael Clark

Department of Earth and Planetary Sciences
1412 Circle Drive
Knoxville, TN 37996-1410
Phone: (865) 974-6006

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