jan 1, 1961 - Harry Hess and R. Dietz used the understanding of mid ocean ridges to tdevelop the theory of sea floor spreading.
Description:
Hess suggested that Earth expanded from the middle, center (mid- ocean ridge). Molten mantle came up through this ridge, which created new sea floor taht spread apart on both sides of the ridge. Hess proposed tat trenches in the ocean were places that the ocean floor fell, and then was recreated.Added to timeline:
Date:
jan 1, 1961
Now
~ 64 years ago