Southeast region, Mexico |
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Paleontology and geologyThe Precambrian: In the Southeastern Region of Mexico, Precambrian rocks form a basement under younger rocks throughout the region and outcrop in a few places in the south. These metamorphic and igneous rocks date back to 1.0 Ga, recording the presence of ancient volcanic islands, mountain ranges, and ocean deposits. They formed along ancient Gondwana, and the movement of tectonic plates brought them to their present location. The Paleozoic: In the Paleozoic, much of the Southeastern Region was covered by shallow to deep seas of the continental shelf, slope, and ocean basin along the coast of Gondwana. These seas were home to various invertebrates and fishes. Toward the end of this era, Gondwana collided with Laurentia to form the supercontinent Pangea. The collision generated volcanism, altering many rocks and raising some areas which became covered in forests and wetlands. By the end of the Paleozoic, much of the region had reached its current position, but the Yucatan Peninsula was pushed against what would become the southeastern United States. The Mesozoic: Pangea rifted apart in the Mesozoic, leaving some rocks from Gondwana in the western part of this region. To the southwest, subduction added new land to the continental margin, causing volcanic eruptions and altering many rocks. The Yucatan Peninsula broke away from the ancient southeast United States and reached its current location. Dinosaurs and other animals inhabited the forests and swamps that covered the land, and the seas were filled with various invertebrates and fishes. By the end of the era, shallow seas flooded in from the Gulf of Mexico, and a huge meteor crashed into the Yucatan, altering the landscape and possibly contributing to the Cretaceous-Tertiary mass extinction. The Cenozoic: In the Cenozoic, the Southeastern Region was pushed up and the seas drained away. Subduction continued in the southwest, forming masses of granite below the surface and causing volcanic eruptions. In the Yucatan Peninsula, fresh water started to dissolve limestone deposits, creating caves, cenotes, and underground rivers. Animals from both North and South America inhabited the forests and grasslands that covered the land. Times of higher sea level are marked by marine deposits and fossilized coral reefs along some coasts. |
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Links to more on Southeast region paleontology |
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