World Ocean Floor.

Description

Heezen & Tharp’s Final Map — The Ocean Floor, Complete at Last.

This is the 1977 World Ocean Floor map produced by oceanographers Bruce Heezen and Marie Tharp and painted by Austrian landscape artist Heinrich Berann. It is widely considered one of the most significant geological maps ever made, representing the culmination of decades of deep-sea research that fundamentally transformed the scientific understanding of the Earth’s structure and history.

The Map in Detail

The map presents the world on a Mercator projection, depicting elevation above and below the waterline across the full extent of the world’s oceans. Ridges, rift valleys, trenches, fracture zones, abyssal plains, continental shelves, and other submarine features are labeled in extensive detail, giving the ocean floor the same cartographic treatment previously reserved for dry land. The sweeping topography of a continuous mid-oceanic ridge system — encircling the entire globe — is rendered with striking clarity, making visible for the first time as a single coherent image the geological forces that drive continental drift.

Historical Context

Heezen and Tharp’s collaboration began at the Lamont-Doherty Geological Observatory of Columbia University in the mid-1950s. Heezen gathered sonar data from research voyages; Tharp, working initially as his cartographic assistant, translated that data into detailed physiographic diagrams of the ocean floor. It was Tharp who first identified an enormous rift valley running along the center of the North Atlantic — and who recognized that this feature was part of a single mid-oceanic range encircling the Earth. The discovery provided crucial observational support for the then-controversial theory of plate tectonics. Heezen and other colleagues were initially skeptical, but the data proved her right.

Despite being the driving intellectual force behind these findings, Tharp’s contributions went largely unacknowledged for years. When their first findings on the Mid-Atlantic Ridge were published in 1956, the work appeared under Heezen’s name alone. Recognition of Tharp’s role came only slowly and belatedly over the following decades. Three earlier maps — each focused on a single ocean basin — had preceded this one, but this 1977 edition was intended as the definitive summation of everything Heezen and Tharp had discovered together. Heezen died the same year it was issued, making it the final product of their partnership. Heinrich Berann’s choice to render the ocean floor was inspired: Berann, celebrated for his panoramic paintings of the European Alps, brought an artist’s eye to data no human had ever directly observed, creating an image of the deep that was as beautiful as it was scientifically rigorous. The map was subsequently published by National Geographic, where it introduced concepts like oceanic rifts and continental drift to a global popular audience.

Publication History and Census

This map was originally produced under the auspices of the Office of Naval Research and Columbia University’s Lamont-Doherty Geological Observatory. Its later republication in National Geographic substantially broadened its reach, though the original printing remains considerably scarcer on the market than the magazine edition. The map is well-represented in institutional collections but is seldom encountered in commerce.