Date of Award

Spring 1998

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ocean & Earth Sciences

Program/Concentration

Geology

Committee Director

G. Richard Whittecar

Committee Member

Randall S. Spencer

Committee Member

Dennis A. Darby

Call Number for Print

Special Collections LD4331.G4 W96

Abstract

The study area lies in a first-order valley on the northwestern slope of Clinch Mountain that drains into Moccasin Creek. The deposit is 50 m long, 25 m wide and approximately 10 m thick and overlies the Ordovician Moccasin Formation. Preserved within the deposit are mammoth and mastodon bones, logs, and plant macrofossils. Radiocarbon analyses indicate the age of the organic-rich sediments ranges from 29, I 00 BP to >44,000 BP, a time period with no fossil remains reported in this region of the Appalachians. Analyses of field observations, textural data, organic carbon content, and plant macrofossils indicate the organic-rich unit is composed of alternating debris flow (pebbly sandy mud) and standing water deposits (massive silt-clay). The stream which carved the valley was diverted midway down the mountain by a large landslide, presumably before the Late Pleistocene. Debris flows and other alluvial deposits from adjacent streams raised the valley bottom of Moccasin Creek and dammed the abandoned lower valley. As much as 5.2 m of organic-rich sediments accumulated in the hollow prior to 29,000 BP. After 29,000 BP, debris fan deposits from adjacent valleys buried the site in nearly five meters of muddy sandy gravel. The presence of Rubus parviflon1s (Thimble Berry) throughout the deposit indicates the study site had a Boreal type environment from >44,000 BP to 29,000 BP. Plant macrofossil evidence indicates the uplands had stands of spruce/jack-pine forest and the valley floor contained ponds and associated boggy areas.

Two debris flows occurred at the Ratliff Site between 29, 100 and 37,900 BP, suggesting a recurrence interval of major storms at the study area of 4,400 years. These suggest that catastrophic storms were not necessarily rare events in the Central Appalachians during the Middle Wisconsinan.

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DOI

10.25777/1zmt-xm69

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