-
Alfred Wegener's Continental Drift Hypothesis
Wegener noticed the coastlines of continents matched up. They seemed to connect like puzzle pieces. He formed the idea of Pangea (the continents used to be attached, but drifted apart over millions of years). The exact date is unknown, so Jan. 1 is inaccurate. -
First Clue For Hypothesis
Wegener accidentally discovered a report that concluded there used to be a land bridge between Brazil and Africa. He conducted his own research based upon this, and gathered that the continents must have shifted. The idea that they have never moved was wrong. The exact day in unknown, so Jan. 1 is inaccurate. -
The Origin of the Continents and Oceans
Alfred Wegener published a book titled "The Origin of the Continents and Oceans" about continental movement which supported his hypothesis. He included evidence from disciplines such as geology, oceanography, and palaeontology. The book gained attention from scientists and started a debate about continental drift. Jan 1 is inaccurate, exact day of publication unknown. -
Response to Hypothesis
As Wegener provided no explanation for how the continents shifted and how plate tectonics functioned, the scientific community rejected his ideas. He was missing a driving force for the shift of tectonic plates. A few scientists believed his theory was important though, but needed more exploration and discussion. This occurred during the 1920s, not just one specific day or year. -
Harry Hess and Seafloor Spreading
U.S. Navy officer and Princeton geology professor named Harry Hess wrote a paper about seafloor spreading: "molten rock seeps up from the Earth’s interior through mid-ocean ridges (undersea mountain chains), spreads out to create new ocean floor, and then sinks back into the Earth’s interior through oceanic trenches." He learned about this after using sonar to map the Pacific ocean during WWII. This was new evidence to support Wegener. Exact date unknown, 1 Jan is an estimate. -
Vine-Matthews-Morley Hypothesis
Paleomagnetists determined that the earth flips its orientation on average every 450,000 years. Geophysicist Fred Vine and geologists Lawrence Morley and Drummond Matthews proposed: "If new oceanic floor is continually being created at mid-ocean ridges, ocean-floor rocks should record past reversals of the magnetic field." (Text 6, Investigation Library). This hypothesis provided the mechanism for Wegener and confirmed Hess's theory. 1 Jan estimate, exact date unknown. -
Acceptance of Continental Drift
With the confirmation of the Vine-Matthews-Morley theory, Harry Hess' seafloor spreading theory was proved. This provided further evidence supporting Alfred Wegener's theory of continental drift, therefore his hypothesis was accepted. After 50 years of disapproval from the scientific community, Wegener was proven right. Many questions were asked and research was conducted to discover more about plate tectonics. This acceptance occurred over many years, not one specific day or year.
