What do you think the origin of the broad, flat surface is above the coastal cliffs shown below?9/24/2023 In the 1950s and 1960s, marine geologists such as Bruce Heezen, Marie Tharp, and Henry Menard used data from echo sounders to map ocean ridges in the North Atlantic and the Pacific. For decades afterward, scientists still did not understand how massive continents could be transported across the face of the Earth, and they had no evidence of any process that could cause continents to move. The “good fit” of the continents and the fossil and rock evidence did not provide enough proof. Like many revolutionary theories, Wegener’s was not initially accepted by scientists. Wegener predicted that heat rising within the hot mantle created currents of partially melted rocks that could move the continents around the earth’s surface. He said that the continents floated atop the mantle-a heavier, denser layer of rocks deep within the earth. In 1915, Wegener proposed his continental drift theory. All this evidence led Wegener to believe that the continents were once connected but had separated and drifted apart. Wegener also noticed that if you could shove western Europe and Africa together with North and South America, their coastlines would fit together very neatly. This suggested that the formations were once whole and later divided. Similar rock formations were also found on distant continents. Similar plant and animal fossils were found in both Africa and South America and on other continents separated by oceans. They believed that the oceans and continents were always where they are now.īut less than 100 years ago, a German scientist named Alfred Wegener took notice of some interesting findings. Until only recently, geologists had thought that Earth’s surface hadn’t changed much since the planet formed 4.6 billion years ago.
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