The Sawatch Uplift is a prominent geologic

Geology

Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 anticline

Anticline

In structural geology, an anticline is a fold that is convex up and has its oldest beds at its core. The term is not to be confused with antiform, which is a purely descriptive term for any fold that is convex up. Therefore if age relationships In structural geology, an anticline is a fold that is...

 in the Rocky Mountains

Rocky Mountains

The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 in central Colorado

Colorado

Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It was formed as a bulge in the North American Plate

North American Plate

The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 approximately 70–65 MYA during the Laramide orogeny

Laramide orogeny

The Laramide orogeny was a period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute, as is the cause. The Laramide...

 that created the modern Rocky Mountains. The uplift runs north-south for several hundred miles from central Colorado into northern New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

. The Sawatch Range

Sawatch Range

The Sawatch Range is a mountain range in central Colorado which includes eight of the twenty highest peaks in the Rocky Mountains, including Mount Elbert, at elevation, the highest peak in the Rockies....

 and Mosquito Range

Mosquito Range

The Mosquito Range is a high mountain range in the Rocky Mountains of central Colorado in the United States. The peaks of the range form a ridge running north-south for approximately 40 miles from southern Summit County on the north end, then along the boundary between Lake and Park counties...

 were both formed as part of the uplift. Approximately 35 MYA, stresses in the continental plate in the center of the uplift caused the center to collapse, forming a trough between the Sawatch and Mosquito Range that is part of the larger Rio Grande Rift

Rio Grande Rift

The Rio Grande Rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. The rift extends from central Colorado in the north to the state of Chihuahua, Mexico in the south. The rift zone consists of four...

. The trough runs southward from Leadville, CO

Leadville, Colorado

Leadville is a Statutory City that is the county seat of, and the only municipality in, Lake County, Colorado, United States. Situated at an elevation of , Leadville is the highest incorporated city and the second highest incorporated municipality in the United States...

 into the New Mexico. The northern part of the rift forms the headwater valley of the Arkansas River

Arkansas River

The Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...

.