Gravity anomalies associated with the Salisbury embayment, Maryland–southern Delaware

Abstract

A simple Bouguer anomaly map has been made for an area that includes southern Delaware and the southern portion of the Eastern Shore of Maryland (lat 37°52.5′ to 38°37.5′N, long 75°00′ to 76°22.50′W). The map does not indicate the presence of the Salisbury embayment, which is known to underlie the mapped area. The map displays several anomalies that can be attributed to intrabasement sources, to variations in basement topography, or to a combination of both. Downward continuation of the map suggests that the sources are either located below the surface of the crystalline basement, or that the deep wells, Hammond 1 and Bethards 1, did not penetrate the basement complex as reported. The map suggests the presence of a sedimentary basin trending north-northeast in the vicinity of Chesapeake Bay. This basin appears to be bordered by two normal or high-angle reverse faults. The map also suggests the presence of another fault, which trends northeast and extends from a few kilometres northwest of Pocomoke City, Maryland, to Millsboro, Delaware, and continues to the northern boundary of the map.