Geology of the igneous rocks of the Spanish Peaks region, Colorado

Abstract

The Spanish Peaks region includes nearly 2,000 square miles in Las Animas and Huerfano as well as small parts of Costilla and Custer Counties in south-central Colorado. The region is mainly an upland area in the westernmost part of the Great Plains, and it borders the eastern foothills of the Sangre de Cristo Mountains. Maximum altitudes are 13,623 feet on West Spanish Peak and 12,708 feet on East Spanish Peak. Regionally, the land slopes in all directions from the Spanish Peaks, but the major streams drain northeastward to the Arkansas River.