Publications

The US Geological Survey (USGS) has been studying a variety of geochemical and geophyscial assessment techniques for concealed mineral deposits. The 2011 field season for this project took place in southwest Alaska, northeast of Bristol Bay between Dillingham and Iliamna Lake. Four maps were created for the geochemistry and geophysics teams to use during field activities.

No abstract available.

This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province...

A thick sequence of limestone, dolomite, and minor sandstone assigned to the Pennsylvanian and lower Permian Bird Spring Formation is exposed in the Ship Mountains about 85 kilometers (km) southwest of Needles, California, in the eastern Mojave Desert. These strata provide a valuable reference section of the Bird Spring Formation in a region where rocks of this age are not extensively...

Laboratory tests to examine hysteresis in the hydrologic and mechanical properties of partially saturated soils were conducted on six intact specimens collected from a landslide-prone area of Alameda County, California. The results reveal that the pore-size distribution parameter remains statistically unchanged between the wetting and drying paths; however, the wetting or drying state...

The Idaho cobalt belt (ICB) is a northwest-trending belt of cobalt (Co) +/- copper (Cu)-bearing deposits and prospects in the Salmon River Mountains of east-central Idaho, U.S.A. The ICB is about 55 km long and 10 km long in its central part, which contains multiple strata-bound ore zones in the Blackbird mine area. The Black Pine and Iron Creek Co-Cu prospects are southeast of Blackbird...

This field guide provides a road log to and geologic descriptions of selected sites in the Idaho cobalt belt, and at the Beartrack gold mine, in the eastern Salmon River Mountains.

The type section of the Barstow Formation in the Mud Hills, north of Barstow, is a reference section for early to middle Miocene paleontology, magnetostratigraphy, and dated volcanic episodes. Thanks to this robust chronologic framework, much of the interpretation of the paleogeography of the region from about 18 Ma to 13 Ma is based on study of the rocks in the Mud Hills. Eastward from...

Supergene jarosite-group minerals are widespread in weathering profiles overlying Pb-Zn sulfide ores at Xitieshan, northern Tibetan Plateau, China. They consist predominantly of K-deficient natrojarosite, with lesser amounts of K-rich natrojarosite and plumbojarosite. Electron microprobe (EMP) analyses, scanning electron microcopy (SEM) investigation, and X-ray mapping reveal that the...

We estimate the thickness of Neogene basin fill along the junction of the Eastern California Shear Zone and the North Frontal thrust system of the San Bernardino Mountains using gravity data with geologic and well log constraints. The geometry of the basin fill is of interest for groundwater assessment and location of potential faults, as well as providing an upper bound on the thickness...

Sandstone-hosted copper (sandstone Cu) deposits occur within a 200-km reach of the northern Chu-Sarysu basin of central Kazakhstan (Dzhezkazgan and Zhaman-Aibat deposits, and the Zhilandy group of deposits). The deposits consist of Cu sulfide minerals as intergranular cement and grain replacement in 10 ore-bearing members of sandstone and conglomerate within a 600- to 1,000-m thick...

On the Navajo Nation, southwestern United States, warming temperatures and recent drought have increased eolian (windblown) sediment mobility such that large, migrating sand dunes affect grazing lands, housing, and road access. We present an assessment of seasonal variations in sand transport, mobility, and ground cover (vegetation and substrate) within a 0.2-km2 study area near Teesto...