Paleogeography of the Southwestern US

This site features maps of the paleogeography of the Southwestern US from 1.8 billion years ago to 10 million years ago. The images were prepared by placing stratigraphic, tectonic, and sedimentologic data on a base map, plotting land versus sea over this data, and then adding climatic data and detailed landforms such as mountains, shelf edges, rivers, arc-trench systems, and lowlands. The maps are organized by time period and when viewed in sequence they show the paleogeographic evolution of the region. Two different interpretations are presented; one showing a tectonic evolution in which most elements of the western US were derived from the North American continent, and the other depicting a tectonic history of exotic terrain accretion. Educational levels: Graduate or professional, Undergraduate upper division