As the CGS continues its research and mapping in the Front Range, it routinely collects and evaluates isotopic age and trace element data for detrital zircon grains to estimate the ages of rock units and sediment sources. This dataset, comprised of 10 samples, is used in mineral resource evaluations, fault investigations, hydrologic unit studies, geologic mapping, and to enhance general geologic knowledge. Future additions to this dataset will be indicated by version dates. Digital ZIP/PDF/XLSX download. ON-004-04D – v20231110
CGS geologists visited multiple sites within the Denver Basin and northeastern Colorado to collect a total of ten samples for detrital zircon age-dating analyses. Target units were chosen based on lack of published ages, use within CGS projects, and access. Samples were obtained from the following rock units (see the location spreadsheets for latitude/longitude coordinates): Fox Hills Sandstone (“Titanium Ridge” and Rooney Road), Laramie Formation (Colorado School of Mines Campus), Arapahoe Conglomerate (Alameda Parkway/C-470), White River Formation (North Sterling Reservoir), Castle Rock Conglomerate (Castlewood Canyon, Douglas County), and Ogallala Formation (Cedar Point near Limon).
At each location, a minimum of 500 grams of sample were collected directly from the outcrop using a rock hammer. Samples were placed within 1-gallon low-density polyethylene bags and shipped to the Isotope Geology Laboratory at Boise State University who conducted the analyses.