Argon ages near Parker, AZ, and Needles, CA

Reported here are argon age data for samples collected to better understand lower Colorado River corridor landscape evolution, the history of the Colorado River, and define the age of geologic units being mapped. Samples of basalts, ashes, and sand were collected in the Cactus Plain southeast of Parker, AZ, the Whipple Mountain piedmont north-northwest of Parker, AZ and washes east-southeast of Needles, CA. Ar/Ar measurements were collected using a Thermo-Fisher Scientific ARGUS VI multi-collector mass spectrometer at the New Mexico Bureau of Geology and Mineral Resources in Socorro, NM. These data were collected as part of efforts to study and map the Lower Colorado River corridor conducted by the U.S. Geological Survey.