Introduction to the seafloor mapping section

Abstract

The widespread use of echo sounders on oceanographic research vessels in the years following World War II revolutionized marine geology by providing a technique for routinely measuring the depth of the seafloor along a ship's track. Within two decades, Precision Depth Recorders (PDRs) had been used to identify the major morphotectonic features in the ocean basins, and compilations of depths measured on thousands of cruise tracks yielded the first reliable global maps of seafloor topography [e.g., Heezen and Tharp, 1960, 1968; Chase et al., 1971]. The existence of these maps played an important role in the development and acceptance of the ideas of seafloor spreading and plate tectonics in the mid and late 1960s.During the past decade the emphasis in marine geology has shifted away from the reconnaissance geographical surveys of the 1950s and 1960s toward much more detailed studies aimed at investigating the important volcanic, tectonic, and sedimentological processes operating in the ocean basins. With this change has come the need for much higher‐resolution bathymetry maps and new techniques for rapidly surveying large areas of the seafloor. The result has been the development of a suite of new seafloor mapping tools with names like Deep Tow, Sea Beam, Sea MARC I and II, GLORIA, and Seasat. These new tools have provided some remarkable new images of the seafloor and promise to revolutionize our understanding of geological processes in the ocean basins in much the same way that the introduction of the precision depth recorder did 40 years ago.