South Dakota History
The geology of South Dakota illustration was created using the cross section drawing from Northern State University. No scale or measurements were followed.
Geologist often have different theories about this topic of study, however many agree that most if not all of South Dakota was under a shallow sea at one time. That period dates back 80 million years or more. Sediment built up on the floor of the sea from crustaceous forms of life that would die and settle to the bottom. These remains would combine with other debris, perhaps plant material that would be blown or carried into the sea. This combination of materials would compress and form layers. When a powerful uplift occurred this sea drained away and left a much different landscape.
The Geologic Story of The Great Plains by Donald E. Trimble is a good reference for the geologic history of the state and the Midwest.
First Peoples of South Dakota
No one knows for sure who the first human inhabitants of South Dakota where. We do know that by 11,500 years ago, as the Ice Age came to a close, the Clovis peoples had burst onto the prehistoric scene. At one site we know of Clovis hunters killed and butchered two mammoths on what is now the Pine Ridge Indian Reservation.
Image and notes above from The South Dakota Story - South Dakota State Historical Society Archaeological Research Center.
Today, the Black Hills area gives us the most complete geologic record of rock history in South Dakota. The Geology of South Dakota, An Educator's Guide to South Dakota's Natural Resources, Northern State University, explains geologic events of the various time periods.
As the landscape of South Dakota change over time (millions of years) it became inhabitable. Dinosaurs were some of the first inhabitants. Dinosaurs lived in South Dakota during the late Jurassic Period, about 150 million years ago, the early Cretaceous Period, about 125 million years ago, and late Cretaceous Period ranging from 80 to 66 million years ago. Dinosaurs varied greatly in size and it is believed that the Black Hills area was where most of the dinosaurs lived.
Badlands National Park is home to one of the largest fossil beds in the world. The spectacular vertebrate fossils preserved within the White River Badlands have been studied extensively since 1846 and are included in museum collections throughout the world. New fossil discoveries are made regularly and these discoveries continue to add to the history of South Dakota.