Ouachita orogeny

The more extensive Ouachita system extends from the current range in Arkansas and Oklahoma southeast to the Black Warrior Basin in Alabama and to the southwest through the Llano, Marathon, and Solitario uplifts in Texas on into Coahuila and Chihuahua in Mexico.

Through the Ordovician, Silurian, Devonian, and early Carboniferous, marine sedimentation left extensive deposits of black shale, quartzose sandstone, and chert beds.

South America approached Laurentia as the intervening oceanic crust was subducted.

The collision of South American and Laurentian continental crust compressed and uplifted the region to form the Ouachita Mountains.

During the Pennsylvanian and Permian, river systems draining westward from the Ouachita Mountains deposited sediments in north-central Texas and Oklahoma, which are now exposed at the surface.