Extending modern cartography to the ocean depths: military patronage, Cold War priorities, and the Heezen–Tharp mapping project, 1952–1959

The first comprehensive map of any ocean basin—covering the North Atlantic region—was created in the US in the 1950s. Compiled by Bruce C. Heezen and Marie Tharp, researchers at Columbia University's Lamont Geological Observatory, the Heezen–Tharp physiographic map of 1957 was significant in several respects. It defined the large-scale physiological provinces of the seafloor, and highlighted its major physical features (including the Rift Valley of mid-oceanic ridge, which Tharp discovered). Military funding for oceanographic research in the early Cold War made possible extensive sea voyages that provided these Columbia researchers sea-floor depth profiles and other critical information; military secrecy persuaded Heezen and Tharp to adopt the physiographic approach when national security restrictions made new bathymetric maps ‘born classified’. But overlooked until now is that the Heezen–Tharp map also deeply depended on extensive support from Bell Labs, then laboring to install the first transatlantic telephone lines. Heezen's hope that the map would support the theory of the expanding earth over the resurrected theory of continental drift did not succeed. But the 1957 North Atlantic Physiographic Chart did reaffirm that representations of the seafloor, mediated by new technologies, fundamentally reflected changing motivations for studying the oceans.