. Collected reprints, Essa Institute for Oceanography. Oceanography mid-ocean rift virtually encircles Africa (except in the Mediterranean) forming a "ghost of Africa," an en- larged outline of the continent, which apparently expanded outward in all directions. The effect of continental breakup can thus be seen around Africa, for it was the heartland of Gondwana. In pre-drift time, only the north coast of Africa now facing the Mediterranean was open to the world ocean. The rift- ing presumably began along the north- east coastline of India, detaching India and then Mada
. Collected reprints, Essa Institute for Oceanography. Oceanography mid-ocean rift virtually encircles Africa (except in the Mediterranean) forming a "ghost of Africa," an en- larged outline of the continent, which apparently expanded outward in all directions. The effect of continental breakup can thus be seen around Africa, for it was the heartland of Gondwana. In pre-drift time, only the north coast of Africa now facing the Mediterranean was open to the world ocean. The rift- ing presumably began along the north- east coastline of India, detaching India and then Madagascar. The splitting then extended southward, along Mo- zambique to Cape Horn, detaching Antartica. Next the rifting turned northward up the Atlantic side of Africa, separating South America. Thus nearly all of the coastline of Africa was blocked out and a modern shoreline established 150-100 million years ago (in late-Jurassic to mid- Cretaceous time), the heroic period of continental drift. The post-Mesozoic period of qui- escence was temporary, ending about 15 million years ago. It now appears that the unstable ends of the snake- like mid-ocean rift have shifted. One tail, formerly in the central Pacific, has swung under western North Amer- ica opening up the Gulf of California and arching the entire western limb of our continent. Another tail, in the Indian Ocean, has circled into the Red Sea and down through eastern Africa, In Australia, the belief is popular that the continents have been dispersed by an expanding Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Institute for Oceanography; Atlantic Oceanographic Laboratories (U. S. ); Pacific Oceanographic Laboratories; United States. Environmental Science Services Administration. Research Laboratories. Washington, D. C. : U. S. Dept. of Commerc
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