Buried rift basin underlying coastal plain sediments, central Delmarva Peninsula, Maryland

Abstract

A recently obtained seismic reflection profile provides the first evidence of a buried rift-basin structure underlying the eastern shore of Maryland. This basin, tentatively named the Queen Anne basin, is buried beneath about 1020 m of plain sediments. The eastern margin of the basin was traversed by the seismic line and appears to be the ramping side of a half-graben structure. It is offset by high-angle, antithetic faults that step the crystalline basement surface down to the west. The border fault system is believed to occur on the western margin of the structure and may coincide with a prominent northeast-trending gravity gradient. Rocks filling the rift basin appear to be at least 1250 m thick. The Queen Anne basin may be part of a buried eastern belt of rift basins that follows the generally arcuate trend of the Appalachian orogen before emerging in Virginia as the Taylorsville and Richmond basins.