PRECAMBRIAN GAP. “There’s a widespread gap in the rock record immediately preceding the Cambrian explosion called the Great Unconformity. The boundary is so prominent—often separating very old igneous and metamorphic rocks from the much younger sedimentary rocks above, as is the case at the base of the Grand Canyon—that all rocks older than this are often lumped together as simply “Precambrian.”
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linkedin post 2022-06-29 05:12:48
Nigel Fleming
September 21, 2022