The Carboniferous in Northwest region, Mexico

Paleontology and geology

In the Carboniferous, shallow to deep waters of the continental shelf and slope covered most of the Northwestern Region of Mexico. Rocks in the deeper waters were deformed, possibly as a series of volcanic islands approached the area. Many different invertebrates lived in the shallow to deep waters, including crinoids, bryozoans, brachiopods, conodonts, radiolarians, and foraminifera, while plants covered the exposed land. By the end of the period, Gondwana neared Laurentia in the east, and as the continental crust began to give way, basins developed in the northeastern part of this region. Many Carboniferous rocks from this region have been removed by erosion or are buried below the surface, but a few small exposures can be found. They are too small to appear on this map, but may be included in the undifferentiated Paleozoic rocks. Other more detailed maps may also show them. Some rocks in the north may have been deposited elsewhere and moved to their present location. Geologists continue to study how and when they formed.