In addition to discovering the midocean ridge system, the oceanographic surveys of post-World War II revealed several other interesting features of the ocean floor. Marine geologists recognized large linear structures associated with the ridges, deep-sea trenches typically fringing the continents, long chains of extinct volcanoes and isolated undersea mountains. At first, these features were difficult to explain using conventional geologic theories. However, in the mid-1960s, each was recognized as playing an important role in the process of plate tectonics. As such, the understanding of each greatly aided the development of this important revolution in geologic thinking.
Fig. 1: Subduction Zones of the World
|The linear features were most often oriented at right angles to the midocean ridge system and offset the ridge. Some of these structures extend nearly halfway across the ocean basins. Among their unusual features were|
The major conceptual
breakthrough that explained
the origin of these
structures and radically altered our interpretation of the oceanís physiographic features was the concept of the transform
This theory, proposed
in 1965 by J.Tuzo
Wilson, suggested that transform faults were a class of faults with characteristics very much different from those associated with faults on
land. Wilson's concept
of the transform fault
was key in the
development of the theory of plate tectonics and was important in explaining how plates interact.
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