GEOLOGY

Detailed explanation-1: -Wegener’s critics correctly pointed out, however, that the continents could not simply “plow” though the ocean floor as Wegener had vaguely theorized. It was Hess who determined how oceanic mountain ranges, called mid-ocean ridges, are fundamental to the tectonic movement that results in the drift of continents.

Detailed explanation-2: -Hess envisaged that oceans grew from their centres, with molten material (basalt) oozing up from the Earth’s mantle along the mid ocean ridges. This created new seafloor which then spread away from the ridge in both directions.

Detailed explanation-3: -Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener’s ideas by using the evidence of seafloor spreading to explain what moved continents.

Detailed explanation-4: -Harry Hess was a geologist and Navy submarine commander during World War II. Part of his mission had been to study the deepest parts of the ocean floor. In 1946 he had discovered that hundreds of flat-topped mountains, perhaps sunken islands, shape the Pacific floor.

Detailed explanation-5: -This theory helped finally confirm Alfred Wegener’s earlier theory of continental drift and helped tie together the modern Plate Tectonic theory. In particular, Hess discovered that mid-ocean ridges, like the Mid-Atlantic Ridge, are the site of underwater volcanic activity that pushes tectonic plates apart.