A quantitative study of the lithosphere and gravity anomalies along the atlantic coast

The principle of isobaric equilibrium is quantitatively applied to a strong lithosphere near a continental boundary. Following methods outlined in earlier papers, the deformation of the lithosphere near Cape Henry is determined from the magnitude and distribution of the sedimentary and fluid load superimposed on the original crystalline basement. From the calculated figure and the equivalent load, the resulting distribution of vertical stress and gravity defect are estimated. Except for the prediction of appreciable positive gravity defects at the continental shelf the calculated and observed gravity distributions are quite similar. The fibre stress due to the deformation is evaluated and it is shown that the position of the calculated maximum stress in tension on the landward side coincides with the observed position of lithospheric failure or the Fall Line. The strength in tension of the upper lithosphere here is shown to be less than 8.5 X 10⁸ dynes/cm². The simultaneous prediction of the approximate magnitudes of the gravity anomalies, their distribution and the location of the Fall line appears to show that a strong elastic lithosphere characterized by the constant b = 8.4 ± 2 × 10^?8 cm^?1 has a real and important geological existence.The investigation shows that due to the finite strength of the lithosphere, long linear areas parallel to continental coast lines are usually regions of disturbed gravity.