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Abraham Ortelius
-Hypothesis: The continents were once joined and that the North and South America were torn away from Europe and Africa.
-Evidence: North America, South America and Africa fit together like jig-saw puzzle.
- Scientific community didn't agree with his hypothesis (just like Alfred's) because he had lack of evidence supporting his theory but he was well known as the first person who made the atlas. -
Alfred Wegener
-Hypothesis: Continental drift and how once all the continents were joined together as a supercontinent called Pangea.
-Evidence: Look- alike animals, plants, fossils and similar rock formations were found in different countries. Also climate clues (South America and India had glacier grooves where glaciers moved and had the same climate as Antarctica) and glossopteris (plant fossils)
- Scientific community didn't agree because of evidence about mechanism, movement and force. -
Arthur Holmes
-Hypothesis: The convection currents within Earth's mantle by radioactive heat caused the mechanism for continental drift.
-Proof: The Earth's mantle contains convection cells that dissipated radioactive heat and moved the crust at the surface.
- Many scientific communities agreed on this theory because backed up Alfred's theory on about continental drift and it's cause of movement/mechanism. -
Harry Hess
-Hypothesis: Sea-floor spreading- Magma slowly leaks out of the cent of mid-ridge from the sea-floor causing new seafloor to form. Then more magma coming out can push the new sea floor away causing the continents to move.
- Evidence- Seafloor drilling led to learning about older rocks away from the mid- Atlantic ridge. Magnetic polarity and continental drift theory also helped.
- Scientific community agreed on his idea because it supported Alfred's theory on the cause of the continental drift. -
Fredrick J. Vine
-Hypothesis: Magnetic stripes on the sides of mid-ridges on the ocean floor were the result of sea-floor spreading.
-Evidence: Continental theory, sea-floor spreading theory, rock fossils, magnetic polarity.
- Scientific community agreed on this hypothesis because it backed up the continental drift theory and the sea-floor theory spreading theory on about the movement. This was the critical theory which helped the plate tectonics theory. -
Lawerence Morley
- Hypothesis: The rocks on the ocean floor were imprinted with a record of the direction and intensity of Earth's magnetic field. -Proof: The alternating pattern of reverse and normal polarity in the rock of the ocean floor and continental drift theory (used this theory)
- Many scientist agreed because it proved the continental drift theory. It explains the originality of movement of plate tectonics.
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Drummand Hayle
Hypothesis: Magnetic stripes on the sides of mid-ridges on the ocean floor were the result of sea-floor spreading.
-Evidence: Continental theory, sea-floor spreading theory, rock fossils, magnetic polarity.
- Scientific community agreed on this hypothesis because it backed up the continental drift theory and the sea-floor theory spreading theory on about the movement. This was the critical theory which helped the plate tectonics theory. -
Edward Bullard
Theory: The Continents all fit together to moved from Pangaea position of the past by utilizing quite specific points of plate movement and rotation.
Proof:Using a depth of 500m instead of shoreline, he matched the true edge of the continents and the continents fit perfectly.He used computer technology to generate the images and calculate the spreading angles for the moving plates
Lots of scientist agreed on the theory because the computers helped it be more accurate and precise than Alfred's.
