High-Resolution Airborne Gravity Gradiometry, Magnetic, and Radiometric Data of Mountain Pass, Southeast Mojave Desert, California

A detailed airborne gravity gradiometry, magnetic, and radiometric survey of Mountain Pass, California was flown by CGG Canada Services Ltd. (CGG). The high-resolution helicopter survey was flown at a flight-line spacing of 100 and 200 m, a flight-line azimuth of 70 degrees, a nominal flight-line elevation above ground of 70 m, and consists of about 1,814 line-kilometers. Tie lines were spaced at a 1-km interval with a flight-line azimuth of 160 degrees. Data were collected using a HeliFALCON airborne gravity gradiometry system, Scintrex CS-3 cesium magnetometer, Radiation Solutions RS-500 spectrometer, and Riegl LMS-Q1401-80n laser scanner and processed by CGG. Gravity gradiometry data include corrections for residual aircraft motion, self gradient, terrain corrections, and tie-line and micro-levelling. Magnetic data were corrected by the contractor for diurnal variations of the Earth?s magnetic field, tie-line leveled, micro-leveled, and an International Geomagnetic Reference Field of the Earth was removed. Radiometric data include corrections for aircraft and cosmic background radiation, radon background, Compton scattering effects, and variations in altitude. Data are provided in ASCII (.csv) and Geosoft database (.gdb) format, database channels and descriptions are listed in the survey report, and grids of gravity and hillshade are in ASCII Grid eXchange Format (.gxf). Maps and grids of magnetic and radiometric data were released by Ponce and Denton (2018a-d). References: Ponce, D.A., and Denton, K.M., 2018a, Aeromagnetic map of Mountain Pass and vicinity, California and Nevada: U.S. Geological Survey Scientific Investigations Map 3412-B, 6 p., 1 pl., scale 1:62,500, https://doi.org/10.3133/sim3412B. Ponce, D.A., and Denton, K.M., 2018b, High-resolution aeromagnetic survey of Mountain Pass, California: U.S. Geological Survey data release, https://doi.org/doi:10.5066/P92XVOOF. Ponce, D.A., and Denton, K.M., 2018c, Airborne radiometric maps of Mountain Pass, California: U.S. Geological Survey Scientific Investigations Map 3412-C, 6 p., 1 pl., scale 1:62,500, https://doi.org/10.3133/sim3412C. Ponce, D.A., and Denton, K.M., 2018d, High-resolution airborne radiometric survey of Mountain Pass, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9ENLS6D.