The Ordovician in Southwest region, Mexico

Paleontology and geology

Except for a few areas in the east, most of the Southwestern Region of Mexico did not exist in the Ordovician. The Ordovician limestones, sandstones, and shales found in the region were deposited off the coast of Gondwana. There are also igneous rocks that formed on the ocean floor when small land masses broke away from that continent in the Early Ordovician. Subsequent collisions have altered, folded, faulted, and pushed these rocks up. Over time, many of them have been buried below younger rocks or eroded away. Ordovician exposures are too small to appear on this map, but other more detailed maps may show them.