The purpose of Colorado Geological Survey’s (CGS) Open-File Report 15-09, Geologic Map of the North Delta 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 in western Colorado. The northern part of the quadrangle contains the southern flank of Grand Mesa and smaller named mesas. The southern portion of the quadrangle contains the Gunnison River and valley. The town of North Delta is located on the north side of the river.
Due to down cutting by the Gunnison River and its tributaries, there are as many as five mapped terraces of alluvial or gravel deposits above the river or stream channels. The exposed bedrock consists of Cretaceous aged formations, including various members of the Mancos Shale and the formations of the Mesaverde Group.
CGS staff geologists David Noe and Jonathan White along field assistant Michele Nelson completed the field work on this project during the summers of 2009 and 2010. 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), unit descriptions, and GIS data. Digital ZIP download. OF-15-09D