GEOLOGY

Detailed explanation-1: -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-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: -The Hess Theory Harry Hess proposed that new seafloor crust was continually formed at mid-ocean ridges. Source: NASA. Hess argued that the Mid-Atlantic Ridge was a boundary where two lithospheric plates were rifting (being pulled apart).

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: -Hess thought that fracture zones were unrelated to the mid-ocean ridges; Dietz, meanwhile believed that the fracture zones were a result of uneven convection motion in the mantle thereby moving parts of the ocean floor at different rates.