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Alfred Lothar Wegener
Alfred Wegener was the first scientist to propose the theory of continental drift. Wegener believed that all the continents had started out as one single land mass called Pangaea before they split and the continents began their never ending journey of drifting apart. Wegener had evidence from fossils and landforms. But, he could not explain how the continents were moved causing many scientist to not support his theory. Weagner's discovery caused many more regarding continental drift to be made. -
Arthur Holmes
Arthur Holmes made a great contribution to the theory of continental drift. He proposed the idea that the continents are carried by the flow of the mantle on which they sit and the mantle flows because it is convecting. But, no evidence was produced until the 1960s to support Holmes's concept. Holmes's theory and research helped us and understand our planet better and the growth of plate techtonics. -
Technology 1920-1950
Ocean floor mapping with sonar started in the 1920s after World War I was over. Sonar divices recorded the depth of the ocean floor by recording the time it took for the sound signal from the ship to bounce off the floor and return. A magnetometer is an instrument used the measure the stregnth and direction of Earth's magnetic field developed in the 1950s. Age-dating of rocks helped scientist know what the age of rocks were near mid ocean ridges and prove sea floor spreading. -
Alexander Du Toit
Alexander Du Toit was one of the first people to support Wegener's theory. Du Toit also added his own discoveries to Wegener's theory. Du Toit discovered that geology in South America and Africa was almost exactly the same. He suggested that there had been two continents: the southern continent of Gondwana and the northern continent of Laurasia, but people still rejected this theory. Du Toit contributed to plate techtonics by helping keep the theory of continental drift alive. -
Kiyoo Wadati
Kiyoo Wadati was a Japanese seismologist who researched deep earthquakes at subduction zones. He discovered the Wadati-Benioff Zone which later became the foundation for the hypothesis of plate techtonics. He was the first person to hypothesize that earth quakes were the result of plate motion. His reaserch helped many other scientist make important discoveries later on in history. -
Hugo Benioff
Hugo Benioff, an American seismologist, is most famous for his study of earthquake focus depth in the Pacific ocean. He was the one who proposed that earthquakes at the Wadati-Benioff zone was due to subduction. This evidence is important because Benioff's discoverys helped explain earthquakes and part of plate techtonics. -
Atlantis
In 1947, a seismologist on the U.S. research ship Atlantis made an important discovery. He discovered a layer of sediment that was very thin. Scientist originally thought that the sediment on the ocean floor was thick because the ocean had been there for 4 million years. It helped raise questions about the age of our ocean floor which would lead to the discovery of sea floor spreading, all of which was important to the development of plate techtonics. -
Sir Edward Bullard
Sir Edward Bullard, a British geophysicist, developed an important theory in 1947, the theory of geomagnetism. According to it, the Earth's magnetic field results from convection in Earth's core. Another contribution Bullard made was to the theory of continental drift. He studied the two rifted continental borders of two continents and when he put them together, they fit perfectly. Sir Edward Bullard helped develop the theory of continental drift. -
Robert S. Dietz
Robert Diez was a marine geologist who along with Harry Hess, came up with the concept of sea floor spreading after thinking that the Hawaiian chain of islands might be moving on a conveyor belt. In Dietz also did research on continental drift and was famous for his reconstruction of the contient Pangea. -
Harry H. Hess
Harry Hess served in the U.S. Navy during World War II. He would use sonar equipment on his ship to measure the depths of the ocean floor. After the war, he continued his research and discovered midocean ridges. He hypothesized the sea floor was spreading from these ridges and started the theory of sea floor spreading. Hess found the missing piece to Wegener's theory of continental drift. This explained how the continents were able to drift apart, proving the theory of continental drift. -
Drummond Matthews and Fred Vine
Drummond Matthews and Fred Vine discovered that the crust surrouding midocean ridges had alternating bands and each was magnatized with the opposite polarity of the surrounding bands. Matthews and Vine thought that each band had the direction of Earth's magnetic field at the tine that piece of ocean floor was created "locked" into it. This discovery was great evidence that supported the theory of sea floor spreading and helped people come to accept that theory. -
Glommar Challenger
The Glomar Challenger was a research ship for the Deep Sea Drilling Project. It drilled holes along an oceanic ridge between South America and South Africa. The core samples retrieved showed deffinate proof for continental drift and sea floor renewal at rift zones. The confirmation of continental drift stregnthened Wegener's hypothesis that all continents started out as one single land mass.
