7 D6. Geomorphology, Quaternary Geology, and Soils (Posters)

Friday, 20 March 2020
8:00 AM - 12:00 PM
Lake Anne

MOCK GLACIAL CLASTS AND LAND FORMS: AN INVESTIGATION INTO CENTRAL APPALACHIAN PERIGLACIAL AND FLUVIAL ANOMALIES

Paper number: 7-11
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

An investigation into the origins of a circular landform was undertaken in Garrett County, Western MD, a region of the Central Appalachians. The original hypothesis based on morphonology and clast form characteristics was that this landform was possibly produced by a small localized body of glacial ice. Following on-site ground truthing, it was determined that former periglacial activity producing boulder fields and subsequent mass wasting events had modified a pre-existing entrenched meander/ Oxbow lake feature. This tentative interpretation was further supported by the use of LIDAR imaging of the area. The image displayed the unmistakable characteristics of fluvial geomorphology being replaced by periglacial activity as the dominant agents of landscape evolution during the Pleistocene. Following the Periglacial activity, late Holocene deforestation prompted mass wasting events, before relative stability returned to the location due to reforestation activity in the early 1900’s. Clast form characteristics originally reflect blocky periglacial origin with average ca:ba ratios of 0.31:0.54 which have been modified by subsequent fluvial activity and based on morphology mimic glacial clasts. Additional data collection is ongoing for a numerical comparison of glacial clast ca:ba ratios to ca:ba ratios collected during this study. A tentative suggestion is that over reliance on ca:ba ratios can cause potential misinterpretation of landform assemblages.

Geological Society of America Abstracts with Programs. Vol. 52, No. 2

doi: 10.1130/abs/2020SE-344548

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