Publications

Process dynamics in fluvial-based dryland environments are highly complex with fluvial, aeolian, and alluvial processes all contributing to landscape change. When anthropogenic activities such as dam-building affect fluvial processes, the complexity in local response can be further increased by flood- and sediment-limiting flows. Understanding these complexities is key to predicting...

Episodic runoff brings suspended sediment to the nearshore waters of West Maui, Hawaiʻi. Even small rainfalls create visible plumes over a few hours. We used mapping, field experiments, and analysis of recent (July 19–20, 2014) and historic rainfall to estimate sources of land-based pollution for two watersheds in West Maui: Honolua, and Honokōwai. Former agricultural fields and some...

Paleomagnetic study of cores from six deep wells provides an independent temporal framework for much of the alluvial stratigraphy of the Quaternary basin beneath the Santa Clara Valley. This stratigraphy consists of 8 upward-fining cycles in the upper 300 m of section and an underlying 150 m or more of largely fine-grained sediment. The eight cycles have been correlated with the marine...

At the Ely Copper Mine Superfund site, Cu concentrations exceed background values in both streamwater (160–1200 times) and sediments (15–79 times). Previously, these sediment samples were incubated with laboratory test organisms, and they exhibited variable toxicity for different stream sites. In this study we combined bulk- and microscale techniques to determine Cu speciation and...

Thick late Miocene nonmarine evaporite (mainly halite and gypsum) and related lacustrine limestone deposits compose the upper basin fill in half grabens within the Lake Mead region of the Basin and Range Province directly west of the Colorado Plateau in southern Nevada and northwestern Arizona. Regional relations and geochronologic data indicate that these deposits are late...

Climate change is already causing, and is expected to continue to cause, a range of health impacts that vary across different population groups in the United States. The vulnerability of any given group is a function of its sensitivity to climate change related health risks, its exposure to those risks, and its capacity for responding to or coping with climate variability and change...

Characterizing the tectonic stress field is an integral part of the development of hydrothermal systems and especially for enhanced geothermal systems (EGS). With a well characterized stress field the propensity of fault slip on faults with known location and orientation can be identified. Faults that are critically oriented for faulting with respect to the stress field are known to...

The chemical composition of feldspar grains in an ignimbrite from the Spanish Canyon Formation in the Alvord Mountain area, California, have been used to confirm similarities in three measured sections locally, and they are similar to exposures of the Peach Spring Tuff (PST) regionally. Feldspar grains were identified on the basis of texture (zoning, as mantled feldspars, or in crystal...

No abstract available.

The Kelton Pass SE and Monument Peak SW 7.5' quadrangles are located in Box Elder County, northwestern Utah (figure 1; plate 1). The northern boundary of the map area is 8.5 miles (13.7 km) south of the Utah-Idaho border, and the southern boundary reaches the edge of mud flats at the north end of Great Salt Lake. Elevations range from 4218 feet (1286 m) along the mud flats to 5078 feet...

Porphyry Cu and porphyry Mo deposits are large to giant deposits ranging up to >20 and 1.6 Gt of ore, respectively, that supply about 60 and 95% of the world’s copper and molybdenum, as well as significant amounts of gold and silver. These deposits form from hydrothermal systems that affect 10s to >100 km3 of the upper crust and result in enormous mass redistribution and potential...

As part of a long term geologic and hydrologic study of several regional groundwater flow systems in western Utah and eastern Nevada, the U.S. Geological Survey was contracted by the Southern Nevada Water Authority to provide geophysical data. The primary object of these data was to enable construction of the geological framework of the flow systems. The main new geophysical data...