-
Period: to
Plate Tectonics
-
Alfred Lothar Wegener
Alfred Lothar Wegener, a German meterologist, was the originator of the Continental Drift theory. His idea was that the continents had, at one time, been attched to eachother. Forming one large land mass, called Pangaea. Wegener had evidence from fossils, climate and land feature, but he was missing one thing to prove his theory possible. He did not know what force was moving the continents. Without Wegener's curiousity, plate tectonics may never have been discovered. -
Technology, 1920s-1950s
After WWI a type of primitive sonar system was used to measure the depth of the ocean. It would measure the time it took for the signal to come beck to it. During the 1950s scientist used magnetometers to detect magnetic variations on the ocean floor. Scientists were not suprised by this because the ocean floor is made of basalt, an iron-rich, volcanic rock. Age dating of rocks helped prove that mid-ocean ridges create new sea floor. The youngest rocks are found closest to the ridge. -
Arthur Holmes
Arthur Holmes, a British geologist, suggested that thermal convectioin currents in the mantle was the force moving the continents. Holmes idea did not get any attention until the 1960's, when more information was known about the sea floor. Other hypotheses published by later scientist had a similar concept, but had more evidence to support them. -
Atlantis
Atlantis, a U.S. research ship, was the first ship built specifically for marine biology, geology and oceanography. It was also the first Woods Hole Oceanographic Institution (WHOI) research ship. The ship had over 3,000 square feet of laboratory space that could be used for a variety of studies. The Atlantis began working in 1931 and finally retired in 1966. -
Hugo Benioff
Hugo Benioff, an American seismologist, is famous for his work on deep focus earthquakes and how they are associated with subduction zones. Earthquakes associated with subduction zones have Benioff's name. He was the first to propose that subduction zones cause deep focus earthquakes, even though he was not the first person to realize the connection. -
Kiyoo Wadati
Kiyoo Wadati, a Japanese seismologist, wrote several papers that influenced modern geophysics. One of his papers proved the evidence of deep earthquakes. He also published the first accurate description of the inclined zone of deep earthquakes. Wadati's work influenced the work of many other scientist. -
Alexander Du Toit
Alexander Du Toit, a South African geologist, modified Wegener's hypothesis. He suggested that their were two continents: Gandwana in the south and Laurasia in the north.Du Toit had more evidence than Wegener had attained, but the hypothesis was still rejected. Du Toit's modification shows that Pangaea seperated into two continents. -
Harry H. Hess
Harry Hess, a Princeton University geologist, was in the U.S. Navy during WWII. While moving from battle to battle, Hess would perform echo-sounding surveys in the Pacific Ocean. He found that in the middle of every ocean was a mid-ocean ridge. This research led him to a hypothesis called sea-floor spreading. This was the evidence Wegener needed to prove his hypothesis, a moving sea floor. -
Robert S. Dietz
Robert S. Dietz, a scientist with the U.S. Coast and Geodetic Survey, discovered the first fracture zone in the Pacific Ocean. This led him to hypothesis that the newly formed crust spread outward at a rate of several centimeters a year. -
Drummond Matthews and Fred Vine
Drummond Matthews and Fred Vine, two Cambridge scientists, published a paper, "Magnetic Anomalies Over Ocean Ridges." In the paper, they proposed that the earth's magnetic field had its polarity reversed a number of time. They suggested that the lava that emerged to form new sea floor would be magnitized with the current magnetic field. -
Sir Edward Bullard
Sir Edward Bullard, a British geophysicist, was a professor at the University of Cambridge. He studied radioactive heat that is generated in the Earth and the Earth's thermal history. Bullard's theory of geomagnetic dynamo was his most important contributions to the study of geomagnetism. -
Glomar Challenger
The Glomar Challenger was a Deep Sea Drilling Project drillship. In 1968, the ship was accepted by the project after a series of tests. For the 30 months after being accepted it drilled in the Atlantic, Pacific, and Indian Ocean, as well as the Mediterranean and Red Sea. The Glomar's most important discovery was at Leg 3, which provided definite proof for the continental drift.
