Overview

The Ancestral Rocky Mountain system covered the entire current Rocky Mountain Range in New Mexico, Colorado, Wyoming, Montana, Utah, and Idaho. This presentation focuses on evidence of uplifts and basins within the Colorado portion of the Ancestral Rocky Mountains. Chapter 1 presents the regional tectonic setting of the Ancestral Rocky Mountains including a brief review of the Ouachita, Antler, and Ancestral Rocky Mountain orogenies before presenting theoretical discussion on subduction flattening theory, the causal mechanisms, and consequences. The chapter continues with the regional geologic history from the Devonian through the Pennsylvanian Period. Chapter 2 discusses the geologic history of Colorado including evidence in Colorado's state park system which displays different formation remnants of sediments shed from the demise of the Ancestral Rockies. Chapter 3 continues with the Central Colorado Trough and the various formations representing erosion of the mountains. Chapter 4 addresses the Eagle Basin Evaporites, The Eagle Valley Formation in a series of section descriptions, Pennsylvanian geologic history, and Pennsylvanian climate in Colorado. Chapter 5 briefly discusses the Apishapa Uplift and Huerfano Park Basin geology. Chapter 6 reviews the Uncompahgre-San Luis Uplift and the Unaweep Canyon. The final Chapter 7 reviews the Paradox Basin formations which represent sediments shed from the rising Uncompahgre highlands.