Publications

Early to middle Miocene lacustrine strata of the Barstow Formation are well dated in just a few places, limiting our ability to infer basin evolution and regional tectonics. At the type section in the Mud Hills, previous studies have shown that the lacustrine interval of the Barstow Formation is between ~16.3 Ma and ~13.4 Ma. Elsewhere, lake beds of the Barstow Formation have yielded...

We explored the use of continuous waterborne electrical imaging (CWEI), in conjunction with fiber‐optic distributed temperature sensor (FO‐DTS) monitoring, to improve the conceptual model for uranium transport within the Columbia River corridor at the Hanford 300 Area, Washington. We first inverted resistivity and induced polarization CWEI data sets for distributions of electrical...

Information on the flow of rivers and streams is a vital national asset that safeguards lives, protects property, and ensures adequate water supplies for the future. The U.S. Geological Survey (USGS) operates a network of more than 9,000 streamgages nationwide with more than 500 in Texas.

Electrical geophysical methods have found wide use in the growing discipline of hydrogeophysics for characterizing the electrical properties of the subsurface and for monitoring subsurface processes in terms of the spatiotemporal changes in subsurface conductivity, chargeability, and source currents they govern. Presently, multichannel and multielectrode data collections systems can...

Saltwater has intruded into many of the coastal aquifers of the United States, Mexico, and Canada, but the extent of saltwater intrusion varies widely among localities and hydrogeologic settings. In many instances, the area contaminated by saltwater is limited to small parts of an aquifer and to specific wells and has had little or no effect on overall groundwater supplies; in other...

A conceptual model of eolian transport is proposed to address the widely distributed, high concentrations of hexavalent chromium (Cr+6) observed in ground water in the Emirate of Abu Dhabi, United Arab Emirates. Concentrations (30 to more than 1000 μg/L Cr+6) extend over thousands of square kilometers of ground water systems. It is hypothesized that the Cr is derived from weathering of...

A suite of complementary, non‐invasive surface geophysical methods was used to assess their utility for site characterization in a pilot investigation at a former defense site in North Kingstown, Rhode Island. The methods included frequency‐domain electromagnetics (FDEM), ground‐penetrating radar (GPR), electrical resistivity tomography (ERT), and multi‐channel analysis of surface‐wave...

Stream and reservoir stage are critical parameters in the computation of stream discharge and reservoir volume, respectively. In addition, a record of stream stage is useful in the design of structures that may be affected by stream elevation, as well as for the planning for various uses of flood plains. This report describes equipment and methodology for the observation, sensing, and...

Paleozoic rocks in the northern Ruby Mountains were metamorphosed during Mesozoic crustal shortening and Cenozoic magmatism, but equivalent strata in the southern Ruby Mountains were never buried deeper than stratigraphic depths prior to exhumation in the footwall of a west dipping brittle normal fault. In the southern Ruby Mountains, Miocene sedimentary rocks in the hanging wall of this...

While the existence of relatively fresh groundwater sequestered within permeable, porous sediments beneath the Atlantic continental shelf of North and South America has been known for some time, these waters have never been assessed as a potential resource. This fresh water was likely emplaced during Pleistocene sea-level low stands when the shelf was exposed to meteoric recharge and by...

An extensive continuous waterborne electrical imaging (CWEI) survey was conducted along the Columbia River corridor adjacent to the U.S. Department of Energy (DOE) Hanford 300 Area, WA, in order to improve the conceptual model for exchange between surface water and U‐contaminated groundwater. The primary objective was to determine spatial variability in the depth to the Hanford‐Ringold...

The potable water system at Fort Knox is threatened by brine contamination from improperly abandoned natural gas exploration wells. The Fort Knox well field is located near the town of West Point, Kentucky, in the flood plain of the Ohio River. At the site, unconsolidated sediments approximately 30 – 40 m thick, overlie shale and porous limestone. Brine is believed to flow vertically...