Gravity anomalies in the western North Atlantic Ocean

Abstract The first accurate gravity measurements in the deep ocean were made in 1923 by Vening Meinesz with pendulum apparatus onboard submarines (Vening Meinesz, 1932). Since that time, and up until the late 1950s, many pendulum stations were occupied in order to obtain information about the earth’s gravitational field over the vast oceanic regions. Though these measurements were accurate (generally 3 or 4 mgal; Ewing and others, 1957) and yielded valuable information concerning the earth’s crust, upper mantle, and isostatic processes, the measurements were discrete and separated by large distances. For this reason, the construction of detailed gravity contour maps of large oceanic areas was virtually impossible. In 1958, continuous gravity measurements at sea aboard surface ships were initiated onboard, U.S.S. Compass Island (Worzel, 1959). Subsequently, gravity measurements have been routinely collected by several of the academic oceanographic institutions and industrial and government agencies. During the 1960s, major technological advances enhanced the reliability of shipboard gravity measurements. These advances included the development of the satellite navigation system (Guier, 1966; Talwani and others, 1966a) to more reliably compute the Eötvös correction and theoretical gravity values, the development of cross-coupling and off-leveling computers to measure errors resulting from shipboard accelerations (Talwani and others, 1966b), the design of reliable temperature control systems for vibrating string instruments (Bowin and others, 1972), and the modification of the LaCoste-Romberg gravity meter for mounting on a stabilized platform (LaCoste, 1967). Accompanying these technological advances, computer systems were developed for rapid