Publications

The Silverton caldera in southwest Colorado, USA hosts polymetallic veins and pervasively altered rocks indicative of porphyry copper systems. Nearly a kilometer of erosion has exposed multiple levels of the hydrothermal systems from shallow lithocaps down to quartz-sericite-pyrite veins. New airborne electromagnetic and magnetic survey data are integrated with previous alteration...

The accuracy and traceability of geochronometers are of vital importance to questions asked by many Earth scientists. The widely applied 40Ar/39Ar geochronometer relies on the co-irradiation of samples with neutron fluence monitors (reference materials) of known ages; the ages and uncertainties of these monitors are critical to our ability to apply this chronometer. Previously, first...

Despite significant investigation of fly ash spills and mineralogical controls on the release of potentially toxic elements (PTEs) from fly ash, interactions with the surficial environment remain relatively poorly understood. We conducted 90-day batch leaching studies with paired analysis of supernatant and solid-phase mineralogy to assess the elemental release and transformation of fly...

Synergistic interactions between geologic structures and topography have long been recognized to reflect numerous Earth processes and rock properties over time. It was not until the advent of plate tectonics in the midtwentieth century that researchers began to view the nature of the northern Cordillera orogen as a quilt of foreign pieces of crust or “suspect terranes”. The Alaska Range...

Tellurium-bearing low-sulfidation epithermal Au-Ag deposits are significant producers of gold, silver, and potentially strategic elements if mineral processing methods are optimized for recovery. Although these deposits are generally related to alkaline magmatism, our study documents an unusual occurrence of Te-rich low-sulfidation epithermal systems in the North Heilongjiang Belt in...

Orogenic gold deposits are comprised of complex quartz vein arrays that form as a result of fluid flow along transcrustal fault zones in active orogenic belts. Mineral precipitation in these deposits occurs under variable pressure conditions, but a mechanism explaining how the pressure regimes evolve through time has not previously been proposed. Here we show that extensional quartz...

Antimony (Sb) is a valuable mined commodity, used mostly in fire retardants, and considered a critical element. It is also a potential environment hazard classed as a carcinogen. Antimony is concentrated in tailings and waste rock from Sb mines as well as other locations, such as precious metal deposits, where Sb is present in the ore but not recovered. This review covers the aqueous...

The re-vegetation of mining wastes with native plants is a comparatively low-cost solution for mine reclamation. However, re-vegetation fails when extreme pH values, low organic matter, or high concentrations of phytotoxic elements inhibit plant establishment and growth. Our aim was to determine whether the combined addition of municipal waste compost and diazotrophic endophytes (i.e

The diversity of geophysical methods and datatypes, as well as the isolated nature of various specialties (e.g., electromagnetic, seismic, potential fields) leads to a profusion of separate data file formats and documentation conventions. This can hinder cooperation and reduce the impact of datasets researchers have invested in heavily to collect and prepare. An open, portable, and well...

Rare earth element (REE) enrichment in the Elk Creek carbonatite, Nebraska USA, is comparable to ore grade enrichment in carbonatite-hosted REE deposits[1]. Petrographic examination of textures documents a complex history of crystallization, brecciation, recrystallization, oxidation, and near surface alteration. Barite (BaSO4) is present in most units, including REE-enriched zones, such...

Magnetotelluric (MT) imaging results from mineral provinces in Australia and in the United States show an apparent spatial relationship between crustal-scale electrical conductivity anomalies and major magmatic-hydrothermal iron oxide-apatite/iron oxide-copper-gold (IOA-IOCG) deposits. Although these observations have driven substantial interest in the use of MT data to image ancient...

Numerous porphyry copper-molybdenum-gold and epithermal deposits define a belt that extends from Eastern Alaska to western Yukon, Canada. An orientation study conducted near the Taurus porphyry deposit was designed to test methods that require minimal sample collection, preparation, and analytical time to determine the viability of indicator mineral studies as a reconnaissance...