Late Precambrian Paleogeography And Tectonics

In the late Proterozoic North America was part of the large supercontinent Gondwana that included Antarctica, Australia, India, Africa, Baltica, and many other cratons. By the Late Proterozoic this supercontinent began rifting apart, forming narrow seas similar to the present-day Red sea between Africa and Arabia. These much older narrow seas were between North America and Antarctica and evolved into major oceans. Huge amounts of subsidence along the margins of these rifts formed very thick passive margin sedimentary wedges. By the end of the Precambrian all the margins around North America were passive, as the other continents drifted away. These and other passive margins formed during the breakup of the late Precambrian supercontinent and contributed to a general global rise in sea level as the amount of young ridges was large, and the average elevation of continents was decreased by continental extension, placing a larger volume of continental material below sea level and displacing an equivalent volume of water onto the continents in a global transgression.

Continue reading here: Early Paleozoic History

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