![]() This once-active divergent plate boundary became the passive, trailing edge of westward moving North America. As the edge of North America moved away from the hot rift zone, it began to cool and subside beneath the new Atlantic Ocean. ![]() At first, the hot, faulted edge of the continent was high and buoyant relative to the new ocean basin. The thick continental crust that made up the new east coast collapsed into a series of down-dropped fault blocks that roughly parallel today's coastline. Meanwhile, North America was slowly pushed westward away from the rift zone. The rift zone known as the mid-Atlantic ridge continued to provide the raw volcanic materials for the expanding ocean basin. ![]() The gash between the spreading continents gradually grew to form a new ocean basin, the Atlantic. ![]() Volcanic eruptions spewed ash and volcanic debris across the landscape as these severed continent-sized fragments of Pangea diverged. Rifting began as magma welled up through the weakness in the crust, creating a volcanic rift zone. ![]() They all existed as a single continent called Pangea. Pangea first began to be torn apart when a three-pronged fissure grew between Africa, South America, and North America. From about 300-200 million years ago (late Paleozoic Era until the very late Triassic), the continent we now know as North America was contiguous with Africa, South America, and Europe. ![]()
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