Publications

Reports of magmatic anhydrite are relatively rare, with only ~30 occurrences documented worldwide so far. However, magmatic anhydrite saturation is difficult to recognize because anhydrite decomposes rapidly in near-surface environments. In most cases, only anhydrite inclusions shielded within other phenocryst phases were able to survive. Alternatively, since anhydrite phenocrysts...

The Magnet Cove alkaline‑carbonatite complex (MCC), located in the Ouachita Mountains of south-central Arkansas in the United States, hosts an extensive variety of rare rock types and critical mineral resources with physical properties (density and magnetization) that contrast significantly with the sedimentary rocks into which they have intruded. Newly acquired ground-based gravity and...

Critical minerals (or critical elements) are minerals or elements that are essential to global security and development and have supply chains vulnerable to disruption. In general, knowledge of the environmental behavior and health effects of critical elements is needed to support the development of safe and environmentally responsible supplies. This knowledge includes identifying...

This step-by-step protocol describes the photogrammetry process used by the U.S. Geological Survey Spokane Imaging Lab (SPIMG) lab to create 3D models of geologic samples. Steps related to photographing small objects are applicable to photogrammetry in general, however, SPIMG-specific steps involving lab hardware and software may not be.

Rare bedrock exposures of the eastern Denali fault zone in southwestern Yukon allow for the measurement, sampling, and analyses of brittle regime fault slip data and deformation mechanisms to explore relations to far field, oblique plate motions. Host rock lithologies and associated slip surfaces show episodic damage zone‐related deformation and calcite ± hematite ± chlorite related...

Degassing of water from magmatic systems is key to transporting metals from magmas to form ore deposits, but elements like chlorine, through the formation of anion complexes, can be important in solubilizing and mobilizing these metals into water-rich fluids. Reconstructing the Cl systematics of evolving magmas is thus an important step towards understanding the origins of ore deposits...

Explosive silicic volcanism of the Carpathian-Pannonian Region (CPR) is increasingly recognized as the primary source of tephra across the Alpine-Mediterranean region during the Early and Middle Miocene. However, the tephrostratigraphic framework for this period of volcanic activity is still incomplete. We present new multi-proxy data from Lower Miocene ignimbrites and tephra fallout...

Over 30 small, discontinuous, tabular carbonatite bodies are located in the Sheep Creek area, Ravalli County, southwest Montana. The age and origin of these REE-Nb-rich deposits are currently being investigated. The purpose of this paper is to document the occurrence of several rare minerals, including daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite, in two of the...

Major- and trace-element data together with Nd and Sr isotopic compositions and 40Ar/39Ar age determinations were obtained for Late Cretaceous and younger volcanic rocks from north-central Colorado, USA, in the Southern Rocky Mountains to assess the sources of mantle-derived melts in a region underlain by thick (≥150 km) continental lithosphere. Trachybasalt to trachyandesite lava flows...

No abstract available.

Options for selecting a high Na concentration mineral for instrument calibration that are suitably stable under the electron beam are limited [1]. NaCl (approximately a mass fraction of 39 % Na) is not practical for use alongside other embedded and polished materials in a mounted block of standards. While albite (NaAlSi3O8; approximately a mass fraction of 8 % Na) represents a typical...

Cultures throughout history have valued jadeite jade (hereinafter jade), a natural material assemblage composed predominately of the NaAl endmember pyroxene, jadeite (NaAlSi2O6) that is prized for its mechanical properties and enticing coloration [1, 2]. The geological setting for the formation of jadeite-rich rocks and associated complex geochemical phenomena is well documented in the...