The purpose of Open-File Report 15-08, a Geologic Map of the Lazear Quadrangle, Delta County, Colorado is to describe the geology, mineral and ground-water resource potential, and geologic hazards of this 7.5-minute quadrangle located east of Delta in western Colorado. This quadrangle contains several gravel capped mesas and a large valley through which the North Fork of the Gunnison flows.
Named mesas include Shamrock Mesa and Redlands Mesa. Due to down cutting by the Gunnison River and its tributaries, there are as many as ten mapped terraces of alluvial or gravel deposits above the stream channels. The exposed bedrock consists predominately of Cretaceous to Jurassic aged formations of shale and sandstone, including the various members of the Mancos Shale.
CGS staff geologist David Noe and field assistants Zachary Logan, Kevin McCall, and Geoffrey Warden completed the field work on this project during the summers of 2010 and 2011. The geologic map plates were created using field maps, structural measurements, photographs, and field notes generated by the investigators. 2 plates: map, cross section, and 3-D oblique view. Also included are GIS data. Digital ZIP download. OF-15-08