dynamic earth
1. Wegner’s hypothesis of continental drift using the observation that the earth’s surfaces are continually changing and other evidence was that the continents had once been joined, and over time had drifted apart but he couldn’t explain the mechanism behind it.
2. Evidence gathered by Ewing, Tharp and Hess that lead to the theory of plate tectonics was:
⦁ In the early 1950s Ewing, with the help of Marie Tharp, a cartographer, mapped the seafloor using available echo profiles, the resulting mapped showed a large canyon that traversed the length of the ridge.
⦁ Hess explains that as new crust is being formed at the ridges old ocean crust is being destroyed as it is pulled back into the Earth in deep ocean trenches which lie along the edges of continents called subduction zones
⦁ Ewig found that beyond the continental shelf the ocean floor contained only recent sediment and unlike what was expected for the 3 billion years of accumulation, instead of being 12 miles thick, the sediment at its thickest was only 1000ft.
⦁ Ewing reached the ridge not only did the sediment get even thinner but dredges also began collecting volcanic rock. Later seismic data would eventually show that the sea floor was composed of basalt, an extrusive igneous rock, and was only a few miles thick.
⦁ Hess would leave the sounding equipment on that would take measurements of the sea floor. It was at this time that Dr. Hess discovered features on the floor of the ocean that appeared to be mountains with the tops flattened.(called guyouts)
Ewig invented explosion seismology (study of earthquakes )
⦁ Through working together their developments enabled the theory of plate tectonics.
In 1953, Maurice Ewing and Bruce Heezen discovered the Great Global Rift and inspired Hess to re-examine the data that he collected while at sea. History of Ocean Basins was published in 1962 and explained the mechanism behind Alfred Wegener's continental drift theory. In the paper Hess described how hot
2. Evidence gathered by Ewing, Tharp and Hess that lead to the theory of plate tectonics was:
⦁ In the early 1950s Ewing, with the help of Marie Tharp, a cartographer, mapped the seafloor using available echo profiles, the resulting mapped showed a large canyon that traversed the length of the ridge.
⦁ Hess explains that as new crust is being formed at the ridges old ocean crust is being destroyed as it is pulled back into the Earth in deep ocean trenches which lie along the edges of continents called subduction zones
⦁ Ewig found that beyond the continental shelf the ocean floor contained only recent sediment and unlike what was expected for the 3 billion years of accumulation, instead of being 12 miles thick, the sediment at its thickest was only 1000ft.
⦁ Ewing reached the ridge not only did the sediment get even thinner but dredges also began collecting volcanic rock. Later seismic data would eventually show that the sea floor was composed of basalt, an extrusive igneous rock, and was only a few miles thick.
⦁ Hess would leave the sounding equipment on that would take measurements of the sea floor. It was at this time that Dr. Hess discovered features on the floor of the ocean that appeared to be mountains with the tops flattened.(called guyouts)
Ewig invented explosion seismology (study of earthquakes )
⦁ Through working together their developments enabled the theory of plate tectonics.
In 1953, Maurice Ewing and Bruce Heezen discovered the Great Global Rift and inspired Hess to re-examine the data that he collected while at sea. History of Ocean Basins was published in 1962 and explained the mechanism behind Alfred Wegener's continental drift theory. In the paper Hess described how hot