Geologic Hazards and A Dynamic Planet

Science
Tutor: None Selected Time limit: 1 Day

Describe how Wegener's continental drift hypothesis has helped to shape modern plate tectonic theory,and why his hypothesis was not widely accepted by his peers when first proposed.

 Analyze the types of evidence used to support plate tectonic theory 

Nov 17th, 2014

To explain these data, Wegener proposed the theory of continental drift in his book The Origins of the Continents and the Oceans, published in German in 1915 and in English in 1924 (Wegener, 1924). His theory stated that all of the continents had originally been joined together during the time period called the Carboniferous (now known to be about 300-360 million years ago) in a supercontinent calledPangaea (see Figure 2 for his depiction). By the Eocene (about 50 million years ago), when new fossilspecies were present that were not as widely distributed, the continents as we know them today had broken apart and were far enough apart that species could not easily migrate from one to the other (see Figure 3 for his depiction).

Figure 2: Wegener’s depiction of Pangaea (Wegener, 1924). The dotted areas would have been warm, shallow seas. Wegener provided the present-day outlines and the rivers for the purpose of identification only.

Figure 3: Additional images from Wegener’s publication showing how the continents “drifted” through time (Wegener, 1924).


 to top

Driving the drift

When Wegener's book was translated into English, French, Spanish, and Russian in 1924, he was widely ridiculed for his suggestion that the continents had moved. One of the main problems with his theorywas that he did not propose a driving mechanism for the motion of the continents. What was the forcethat moved the continents? Where did it come from? How much force was needed to move a continent?

The driving mechanism, an important key to the continental drift theory, lay out of reach until the 1960s. Wegener had made his claims based on data from the continents, but the oceans cover 70 percent of Earth's surface – a vast area hidden from his view under kilometers of water. But the first and second World Wars brought major technical and scientific developments that allowed scientists to (1) map the ocean floor and (2) measure the magnetism of seafloor rocks in detail. These two sets of data provided geologists with additional evidence for the process of continental drift.

http://www.visionlearning.com/en/library/Earth-Science/6/The-Origins-of-Plate-Tectonic-Theory/65

Nov 17th, 2014

Did you know? You can earn $20 for every friend you invite to Studypool!
Click here to
Refer a Friend
...
Nov 17th, 2014
...
Nov 17th, 2014
Feb 23rd, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer