Publications

Regional stream and pond sediment, panned concentrate, and water sampling at and around known mineral occurrences in the Tyonek quadrangle, Alaska Range, Alaska were undertaken to determine geochemical signatures in the different media. For sediment samples, two different size fractions (− 80 mesh and − 230 mesh) were analyzed. Elevated concentrations (mostly ~ 2 × median) of elements such as As,

Hand-collected grab samples are the most common water sampling method but using grab sampling to monitor temporally variable aquatic processes such as diel metal cycling or episodic events is rarely feasible or cost-effective. Currently available automated samplers are a proven, widely used technology and typically collect up to 24 samples during a deployment. However, these automated samplers are

Pressure disequilibria during rapid valve closures can affect calculated molar quantities for a range of gas abundance measurements (e.g., K-Ar geochronology, (U-Th)/He geochronology, noble gas cosmogenic chronology). Modeling indicates this effect in a system with a 10 L reservoir reaches a bias of 1% before 1000 pipette aliquants have been removed from the system, and a bias of 10% before 10,000

Many epithermal gold-silver deposits are temporally and spatially associated with late Oligocene to Pliocene magmatism of the southern ancestral Cascade arc in western Nevada and eastern California. These deposits, which include both quartz-adularia (low- and intermediate-sulfidation; Comstock Lode, Tonopah, Bodie) and quartz-alunite (high-sulfidation; Goldfield, Paradise Peak) types, were major p

Water column redox conditions, degree of restriction of the depositional basin, and other paleoenvironmental parameters have been determined for the Mississippian Kuna Formation of northwestern Alaska from stratigraphic profiles of Mo, Fe/Al, and S isotopes in pyrite, C isotopes in organic matter, and N isotopes in bulk rock. This unit is important because it hosts the Red Dog and Anarraaq Zn-Pb-A

The biotic ligand model (BLM) is a numerical approach that couples chemical speciation calculations with toxicological information to predict the toxicity of aquatic metals. This approach was proposed as an alternative to expensive toxicological testing, and the U.S. Environmental Protection Agency incorporated the BLM into the 2007 revised aquatic life ambient freshwater quality criteria for Cu.

This paper reviews the basic chemistry of cyanide, methods by which cyanide can be analyzed, and aspects of cyanide behavior that are most relevant to environmental considerations at mineral processing operations associated with gold mines. The emphasis is on research results reported since 1999 and on data gathered for a series of U.S. Geological Survey studies that began in the late 1990s. Cyani

Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a

The Mesozoic magmatic history of the North American margin records the evolution from a more segmented assemblage of parautochthonous and allochthonous terranes to the more cohesive northern Cordilleran orogenic belt. We characterize the setting of magmatism, tectonism, and epigenetic mineralization in the western Fortymile mining district, east-central Alaska, where parautochthonous and allochtho

The Hideaway Park tuff is the only preserved extrusive volcanic unit related to the Red Mountain intrusive complex, which produced the world-class Henderson porphyry Mo deposit. Located within the Colorado Mineral Belt, USA, Henderson is the second largest Climax-type Mo deposit in the world, and is therefore an excellent location to investigate magmatic processes leading to Climax-type Mo mineral

Between 12 July 2008 and 18 January 2010 a seismic swarm occurred close to the town of Court-Saint-Etienne, 20 km SE of Brussels (Belgium). The Belgian network and a temporary seismic network covering the epicentral area established a seismic catalogue in which magnitude varies between ML -0.7 and ML 3.2. Based on waveform cross-correlation of co-located earthquakes, the spatial distribution of th

‘Waste stream’ is a general term that describes the total flow of waste from homes, businesses, industrial facilities, and institutions that are recycled, burned or isolated from the environment in landfills or other types of storage, or dissipated into the environment. The recovery and reuse of chemical elements from waste streams have the potential to decrease U.S. reliance on primary resources