Geophysical investigation of the structural framework of the Newark-Gettysburg Triassic basin, Pennsylvania
A residual gravity map of the Newark-Gettysburg Triassic basin has been constructed using approximately 5,000 gravity stations that are nominally 1 to 5 km apart. In a general way, the map shows gravity lows over Triassic sedimentary rocks and gravity highs over Triassic diabase bodies and pre-Triassic rocks that flank the basin. Steep gravity gradients within the basin, but near the margins, are interpreted to be due to vertical offset on faults within the basin. The presence of these presumed faults along parts of the southern margin indicates that the basin is not a simple half-graben, but is internally faulted, with irregular sediment thicknesses.