Publications

The southwestern part of the Cima volcanic field in the Mojave National Monument, California, contains many of the youngest basaltic cinder cones and lava flows in the field (Wilshire and others, 2002). In 2014 the Hyperspectral Thermal Emission Spectrometer (HyTES) collected a swath of data across this area. This summary describes the HyTES instrument, data, and images, and compares two standar

Wilderness areas in the Mojave Desert, California, are remote and rugged terrain, but they contain important geology for understanding faults of the eastern California shear zone (ECSZ), and remote sensing offers techniques that can optimize mapping. The Bristol–Granite Mountain fault zone (BGMFZ) is the easternmost fault of the ECSZ with the Marble, Bristol, and Old Dad mountains on either side o

Preliminary interpretation of new and updated incision rates in western Grand Canyon shows the effects of Quaternary faulting, which dampens river incision rates in the footwalls and amplifies them in the hanging walls of normal faults. In the reach between Lava Falls and Diamond Creek in western Grand Canyon, about 178 to 225 river miles downstream from Lees Ferry, the river crosses the neotecton

This study provides new stratigraphic data and identifications for fossil marine mammals from the Monterey Formation in the Capistrano syncline, Orange County, California, showing that there are two distinct marine mammal assemblages. Until now, marine mammals from the Monterey Formation of Orange County have been considered to represent a single assemblage that is 13.0–10.0 Ma in age. By combinin

Two new joint gravity-magnetic models in northern Coachella Valley provide additional evidence for a steep northeast dip of the Mission Creek strand of the southern San Andreas fault (southern California, USA). Gravity modeling indicates a steep northeast dip of the Banning fault in the upper 1–2 km in northern Coachella Valley. The Mission Creek strand and its continuation to the southeast (Coach

Basalt, a mafic volcanic rock common in mid-ocean islands and in several continental settings, is melted from upper mantle rocks in many cases and thus provides information on mantle conditions. Basalt lava fields, some decorated with cinder cones, are scattered around the Mojave Desert. Only a few basalt fields have been well studied, so we undertook a compilation of basalt fields that are younge

Silicic volcanism that postdates widespread early Miocene volcanism in the Mojave Desert is underappreciated. We compiled age, petrographic, and geochemical data for volcanic rocks in a wide swath of the desert south of the Garlock fault using an age threshold of post-18.8 Ma, approximately the limit of the earlier Miocene volcanism as marked by the eruption of the widespread Peach Spring Tuff. In

For millennia, forest ecosystems in California have been shaped by fire from both natural processes and Indigenous land management, but the notion of climatic variation as a primary controller of the pre-colonial landscape remains pervasive. Understanding the relative influence of climate and Indigenous burning on the fire regime is key because contemporary forest policy and management are informe

Observations of relative paleointensity reveal several forms of asymmetry in the time dependence of the virtual axial dipole moment (VADM). Slow decline of the VADM into a reversal is often followed by a more rapid rise back to a quasi-steady state. Asymmetry is also observed in trends of VADM during times of stable polarity. Trends of increasing VADM over time intervals of a few 10s of kyr are mo

Though primary sources of carbon (C) to soil are plant inputs (e.g., rhizodeposits), the role of microorganisms as mediators of soil organic carbon (SOC) retention is increasingly recognized. Yet, insufficient knowledge of sub-soil processes complicates attempts to describe microbial-driven C cycling at depth as most studies of microbial-mineral-C interactions focus on surface horizons. We leverag

The Archean age granite gneiss basement along the Prydz Bay coastline in East Antarctica hosts north–south-, east–west-, NE–SW- and NW–SE-trending mafic dyke swarms in the Vestfold Hills region that intruded between 2420 and 1250 Ma. The dyke trends do not show a direct correlation with the dyke geochemistry but can be broadly discriminated into high-Mg and Fe-rich tholeiites. The former type are

Previous moderate- and high-temperature geothermal resource assessments of the western United States utilized weight-of-evidence and logistic regression methods to estimate resource favorability, but these analyses relied upon some expert decisions. While expert decisions can add confidence to aspects of the modeling process by ensuring only reasonable models are employed, expert decisions also in