The purpose of the CGS Open-File Report OF-15-05, Geologic Map of the Hayden Quadrangle, Routt County, Colorado is to describe the geology, mineral and ground-water resources, and geologic hazards of this 7.5-minute quadrangle located around the town of Hayden in western Colorado.
The Hayden quadrangle contains three structural features of note: (1) the Williams Fork Mountains in the southwestern corner; (2) the Sage Creek anticline in the southeastern corner; and (3) the Sand Wash Basin in the northern half. Sedimentary strata in the Williams Fork Mountains and Sand Wash Basin generally dip toward the north-northeast, while strata on the western flank of the Sage Creek anticline generally dip toward the west and northwest. These structural uplifts, basins, and folds are interpreted to be compressional features of Laramide age (Dickinson and others, 1988). Superimposed upon those features on the western side of the quadrangle are a series of small faults, anticlines, and synclines. They occur along two, roughly orthogonal axes, trending NNE-SSW and WNW-ESE. We interpret that the folding may be Laramide in age and caused by movements of basement sub-blocks during the formation of the main structural features. The faulting appears to be younger. The faults appear to be normal faults that cleanly cut across strata with no associated folding. We interpret that the faulting occurred during Miocene extension in Colorado, associated with a period of regional uplift and rifting (Chapin and Cather, 1994).
CGS staff geologists David Noe and Peter Barkmann, and field assistants Kevin McCall, Michael Zawaski, Zachary Logan, and Daniel Hosler completed the field work on this project during the summers of 2010 and 2011. The geologic map plates and descriptions were created using data from field maps, structural measurements, photographs, and field notes generated by the investigators. 2 plates (map, cross-section, and 3-D oblique view) and GIS data. Digital ZIP download. OF-15-05D