Preliminary free-air gravity anomaly map of the Gulf of Mexico from surface-ship measurements and its tectonic implications

Abstract

Free-air gravity anomalies have been obtained aboard the R.V. Hidalgo in the Gulf of Mexico with a LaCoste and Romberg surface-ship gravity meter. The data obtained are along several profiles between the Texas coast and the Yucatan Peninsula and along profiles in portions of the western Gulf of Mexico, across the West Florida escarpment, and east of Yucatan. The accuracy of measurements is estimated to be within ±12 mgal. A preliminary map of free-air anomalies is presented and some of its crustal structural implications are discussed, particular reference being made to a profile from the Yucatan Peninsula to Beaumont, Texas. Free-air anomalies obtained in the main basin of the Gulf display fairly large variations from −60 to +40 mgal. The gravity data are in agreement with those published by Vening Meinesz and Wright on the basis of their 1928 submarine pendulum measurements if certain corrections are made to their measurements, but they are in large disagreement with one pendulum measurement. The gravity meter data indicate, contrary to former opinions based on too few data and speculations, that the main basin of the Gulf is nearly in isostatic equilibrium.