Document Type

Thesis

Abstract

The Yorktown-Eastover Aquifer consists of late Miocene-Pliocene sediments which overlay part of the Chesapeake Bay Impact Structure (CBIS). This structure was formed 35 Ma when an extraterrestrial object landed near Cape Charles, Virginia. The Cretaceous - Eocene sediments in the immediate vicinity — dramatically rearranged by direct impact or secondary tsunami waves. All sediments deposited since that event have been affected by the underlying structural changes. Traverses along a 2.25 mi (3.6 km) section of the York River were examined for evidence of structural change, which would be present in the Tertiary sediments of the Chesapeake Group. Changes were evident in the traverse, but the borehole data available is not sufficient enough to draw definitive conclusions. Observed stratigraphic differences could also be due to less dramatic causes, such as dissolution features, or facies, which reflect sedimentary environments due to underlying structure. Due to the highly variable definitions of the members of the Yorktown and Eastover Formations, the CBIS as the primary factor in the changes cannot be convincingly postulated, although it is likely a contributing factor to the observed anomalies.

Date Awarded

2000

Department

Geology

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