While it has been known for some time that reducing fluids have bleached red beds adjacent to fault zones and regionally across the Colorado Plateau, the volumes of fluids expelled along faults have never been quantified. We have developed and applied a suite of one-dimensional hydrologic models to test the hypothesis that internally generated, reducing fluids migrated up sub-basin bounding faults across the Paradox Basin and bleached overlying red beds. The internal fluid driving mechanisms included are mechanical compaction, petroleum and natural gas generation, aquathermal expansion of water, and clay dewatering. The model was calibrated using pressure, temperature, porosity, permeability, and vitrinite reflectance data. Model results indicate that sediment compaction was the most important pressure generation mechanism, producing the majority of internal fluids sourced during basin evolution. Peak fluid migration occurred during the Pennsylvanian-Permian (325-300 Ma) and Cretaceous (95-65 Ma) periods, the latter being concurrent with simulated peak oil/gas generation (87-74 Ma), which likely played a role in the bleaching of red beds. Batch geochemical advection models and mass balance calculations were utilized to estimate the volume of bleaching in an idealized reservoir having a thickness (similar to 100 m) and porosity (0.2) corresponding to bleached reservoirs observed in the Paradox Basin. Bleaching volume calculations show that internal fluid driving mechanisms were likely responsible for fault-related alteration observed within the Wingate, Morrison, and Navajo Formations in four localities across the Paradox Basin in the Colorado Plateau, Utah and Colorado, USA. The volume calculation required that 33%-55% of the total basinal fluids, composed of hydrogen-sulfide and paleo-seawater, migrated into an overlying red bed reservoir (0.5 wt% Fe2O3).

Broadly similar U(-V) deposits are hosted by Permian to Jurassic sandstones in the Paradox Basin of the Colorado Plateau. Common features of all the Paradox Basin deposits include occurrence in bleached red bed sandstones; accessory barite and/or celestine; authigenic Ti minerals; lack of correlation between mineralization and plant coal distribution; and evidence for or actual traces of hydrocarbons in the rock before and/or during mineralization. All but the structure-hosted Cutler deposits also show a mix of hematite, pyrite, and hypogene U and/or V minerals enclosed under authigenic overgrowths surrounding detrital quartz cores, which are extensively replaced by fringes of vanadian phyllosilicates. In the Entrada-hosted deposits, all but traces of hypogene U and V oxides have been removed to leave mainly the V-phyllosilicate minerals, but otherwise they resemble the mineralogy and paragenesis in the rest of the Paradox Basin U-V deposits. This paper presents and compares the deposit types to each other and to global sandstone-hosted U resources. Deposits hosted in the Jurassic Salt Wash Member of the Morrison Formation mostly form tabular, V-dominated bodies in permeable, trough cross-bedded horizons of bleached former red beds. Common quartz overgrowths entrap pyrite, pitchblende, and montroseite. Pitchblende and montroseite also form interstitial masses in cementing V-phyllosilicates, which corrode and partially replace the quartz overgrowths. Common accessory phases include pyrite (some framboidal), chalcopyrite, ferroselite, clausthalite, galena, sphalerite, and barite, with minor asphalt globules that corrode quartz overgrowths and cores and contain pitchblende and pyrite. Down the stratigraphic section, the Jurassic Entrada hosts minor lenticular deposits in aeolian sandstones just below a capping limestone. Ore minerals consist mainly of roscoelite replacing quartz overgrowths and cementing the sandstone. Except for small vanadiferous pitchblende inclusions trapped under quartz overgrowths, minor U-vanadates are the only U minerals observed. Continuing down-section, U-V deposits in the Triassic Chinle occur in conglomerates and sandstones just above the Chinle-Cutler unconformity in the Big Indian district, and in the basal Chinle in White Canyon. Quartz overgrowths are rarer but also enclose inclusions of hematite and pitchblende, more rarely V minerals. Pitchblende, montroseite, and V-phyllosilicates are the main ore minerals, forming interstitial masses and replacing some of the plant coal in the rocks. Accessory minerals include pyrite, sphalerite, galena, and barite. Secondary fluid inclusions fluoresce bright blue in ultraviolet light, indicating hydrocarbons. Chinle-hosted deposits in the San Rafael Swell occur as uraniferous asphalt that also contains V-Cr-Fe oxide. Roscoelite hosts most of the V and the deposits contain a large suite of accessory minerals, including pyrite, chalcopyrite, Ni-arsenide, sphalerite, galena, realgar, and barite. Where bleached, the coarse sandstone of the underlying Cutler Formation hosts small deposits below or near Chinle orebodies, either along permeable sandstones or along steep faults. Cutler-hosted deposits showing stratigraphic control share most features with the nearby Chinle orebodies, including quartz and rarer feldspar overgrowths enclosing U-V minerals and an assemblage dominated by pitchblende and montroseite with minor V-phyllosilicates. Deposits hosted along faults in the Cutler are highly distinct, mineralized with pitchblende and uraniferous asphalt in the fault cores and V-phyllosilicate in surrounding areas. Alone among the U and V deposits of the Paradox Basin, no quartz overgrowths have been observed in this type. Deposits’ interpreted parageneses are also similar, with bleaching of original red beds during or shortly before the beginning of mineralization, followed by further U-V deposition in the main ore stage. Late in the ore stage, fresh V or V (hydr)oxide minerals back-reacted with silica in quartz overgrowths to form V-phyllosilicates, while accessory base metal sulfides and selenides precipitated along with barite. These similarities of mineralogy and texture imply a similar mechanism of formation for most of the Paradox Basin U-V deposits, corresponding either to a single basinwide ore-forming event or to the same geologic processes independently repeated in different strata at different times. Hydrocarbons were likely a major reductant, with ore precipitating where an oxidized metal-bearing fluid either mixed with hydrocarbons or entered a rock previously reduced by their passage. Lastly, the Paradox Basin deposits’ most remarkable feature is their high V content, which is unique worldwide and makes the area a world-class resource for this critical green energy metal.

This paper synthesizes new and previous work on the tabular sandstone-hosted uranium and vanadium deposits of the La Sal district, one of the principal U-V districts of the Colorado Plateau. Deposits form a 1–3 km wide, E-W trending 30 km long trend spanning the Utah-Colorado border, approximately orthogonal to the Uravan belt. Ore is hosted in the uppermost fluvial subarkosic sandstones of the Salt Wash Member of the Jurassic Morrison Formation and typically forms channel-parallel, elongate orebodies up to 180 m long, 90 m wide, and 1 m thick. Sandstones are interbedded with silty, muddy, and calcareous units. Principal mineralogical changes include quartz overgrowths accompanied by destruction of early diagenetic hematite. Precipitation of compositionally distinct carbonate cements and clays followed. Bleaching was prior to and/or contemporaneous with mineralization, which is restricted to bleached rocks. Petrography shows that ore minerals (uraninite, coffinite, and montroseite) in part predate growth of authigenic quartz and calcite cements, followed by the formation of ferroan dolomites. Abundant V-rich phyllosilicates may reflect back-reaction of montroseite with quartz and other minerals. New U-Pb dating of ore-hosting calcite ( 144 Ma) and K-Ar dating of V-clays ( 42–36 Ma) parallel published results for elsewhere on the Plateau. Sedimentary structures (e.g., crossbedding), primary porosity, and the distribution of lithofacies in the local Salt Wash channel system control mineral growth. The thin section- to district-scale observations suggest that mineralization formed either by mixing of two fluids, or alternatively by reaction of oxidized fluids with a reductant earlier introduced during bleaching, as has been suggested in other Plateau deposits.

The Battle Mountain area is a major porphyry style Au (-Cu) district in northern Nevada, forming one end of the Battle Mountain-Eureka mineral trend. This trend, along with several others in the north-central Nevada region, hosts some of the world's most prolific gold mineralization, which is oftentimes associated with a suite of trace elements including arsenic, antimony, tungsten, and thallium and can be related to or overprinted by hydrothermal alteration. However, determining the extent of control hydrothermal fluids exert on some of the deposits in the region has been difficult to ascertain. One of the associated trace metals in the region, thallium (Tl), is a highly incompatible element and, as such, dominantly resides in the continental crust, where it can be easily remobilized during hydrothermal alteration. While previous work has demonstrated the effects of hydrothermal alteration on Tl distribution and fractionation, the controls responsible for the observed Tl fractionation during hydrothermal alteration are still poorly characterized but may provide insight into fluid behavior. Here, we present new Tl isotope composition and concentration data for a suite of 54 mineral separates obtained from 43 samples from the Battle Mountain area, which range from unaltered intrusive igneous rocks through varying types and degrees of hydrothermally altered rocks. Measured Tl concentrations vary by more than an order of magnitude, from below detection limit (0.2 ppm in this study) to 2.0 ppm, while epsilon 205Tl ranges between -5.0 and +2.2 (epsilon 205Tl is the deviation of the 205Tl/203Tl isotope ratio of a sample from a standard in parts per 104). Thallium concentrations correlate positively with whole-rock potassium (K), thus show strong increases during K alteration, and demonstrate significantly lower epsilon 205Tl values within K-altered samples. Conversely, during later, overprinting Na-Ca alteration, both K and Tl are removed, resulting in a noted decrease in Tl concentrations coupled with a shift to significantly higher epsilon 205Tl values. It appears that during hydrothermal alteration, 203Tl is more easily (re)mobilized and (re)distributed, which reflects: 1) a first-order hydrothermal alteration control that relates to the transport of Tl during the formation of a new, metasomatic mineral assemblage (particularly the breakdown and/or formation of K-bearing minerals) and 2) a second-order mineralogical control, relating to inter-mineral equilibrium, which also results in a small fractionation effect.

The Paradox Basin in the Colorado Plateau (USA) has some of the most iconic records of paleofluid flow, including sandstone bleaching and ore mineralization, and hydrocarbon, CO2, and He reservoirs, yet the sources of flu-ids responsible for these extensive fluid-rock reactions are highly debated. This study, for the first time, characterizes fluids within the basin to constrain the sources and emergent behavior of paleofluid flow resulting in the iconic rock records. Major ion and isotopic (delta O-18(water); delta D(wate)r; delta O-18(SO4); delta S-34(SO4); delta S-34(H2S); Sr-87/Sr-86) signatures of formation waters were used to evaluate the distribution and sources of fluids and water-rock interactions by comparison with the rock record. There are two sources of salinity in basinal fluids: (1) diagenetically altered highly evaporated paleo-seawater-derived brines associated with the Pennsylvanian Paradox Formation evaporites; and (2) dissolution of evaporites by topographically driven meteoric circula-tion. Fresh to brackish groundwater in the shallow Cretaceous Burro Canyon Forma-tion contains low Cu and high SO4 concentrations and shows oxidation of sulfides by meteoric water, while U concentrations are higher than within other formation waters. Deeper brines in the Pennsylvanian Honaker Trail Formation were derived from evaporated paleo-seawater mixed with meteoric water that oxidized sulfides and dissolved gypsum and have high Sr-87/Sr-86 indicating interaction with radiogenic siliciclastic minerals. Upward migration of reduced (hydro- carbon-and H2S-bearing) saline fluids from the Pennsylvanian Paradox Formation along faults likely bleached sandstones in shallower sediments and provided a reduced trap for later Cu and U deposition. The distribution of existing fluids in the Paradox Basin pro-vides important constraints to understand the rock record over geological time.

Geometallurgical assessment of orebodies in the mining industry typically relies on bench-scale or lab-based characterization techniques. In this study, we investigate drone- and tripod-based field hyperspectral imaging as a potential addition to the geometallurgy toolkit in multiple applications. This pilot study tests hyperspectral imaging for large-scale mineral mapping in and around the active Lisbon Valley copper mine, including natural exposures, previously producing U-V mines, highwalls, dumps, and leaching sites. Tests include different (supervised and unsupervised) mineral data classification methods, varying mineral spectral reference libraries, comparison with ground-truth geological and spectroscopic mapping and sampling, and integration with LiDAR data. The results show that hyperspectral scans can produce spatially registered maps of the distribution of different spectrally active mineral types over dumps, highwalls, leach pads, and natural outcrops. Clays, other phyllosilicates, carbonates, and sulfates showed up particularly well. The sensor was also able to distinguish dry from lixiviant-saturated areas and map different clay types on the leach pads, and shows promise for differentiating types and health of vegetation. These results suggest that hyperspectral imaging, if coupled with robust ground-truthing, can be a useful complement to existing geometallurgical techniques in the mining industry, such as geological mapping, blast hole sampling and automated mineralogy identifications, and handheld spectrometry. In particular, hyperspectral imaging has promise for mapping the distribution of acid-consuming minerals; mapping the distribution of swelling, sliming, and heap-blinding clays; and pinpointing problem areas on heap leach pad surfaces.

ADVERTISEMENT RETURN TO ISSUEPREVCorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to "Recovery of Critical Metals from Aqueous Sources"Serife E. Can SenerSerife E. Can SenerMore by Serife E. Can Senerhttps://orcid.org/0000-0002-8085-7367, Valerie M. ThomasValerie M. ThomasMore by Valerie M. Thomashttps://orcid.org/0000-0002-0968-8863, David E. HoganDavid E. HoganMore by David E. Hogan, Raina M. MaierRaina M. MaierMore by Raina M. Maierhttps://orcid.org/0000-0002-0421-4677, Michael Carbajales-DaleMichael Carbajales-DaleMore by Michael Carbajales-Dale, Mark D. BartonMark D. BartonMore by Mark D. Barton, Tanju KaranfilTanju KaranfilMore by Tanju Karanfilhttps://orcid.org/0000-0003-0986-5628, John C. CrittendenJohn C. CrittendenMore by John C. Crittendenhttps://orcid.org/0000-0002-9048-7208, and Gary L. AmyGary L. AmyMore by Gary L. AmyCite this: ACS Sustainable Chem. Eng. 2021, 9, 44, 15072Publication Date (Web):October 26, 2021Publication History Received6 October 2021Published online26 October 2021Published inissue 8 November 2021https://pubs.acs.org/doi/10.1021/acssuschemeng.1c06821https://doi.org/10.1021/acssuschemeng.1c06821correctionACS PublicationsCopyright © 2021 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views849Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (489 KB) Get e-AlertscloseSUBJECTS:Coal,Manufacturing,Power,Seawater,Water Get e-Alerts

Critical metals, identified from supply, demand, imports, and market factors, include rare earth elements (REEs), platinum group metals, precious metals, and other valuable metals such as lithium, cobalt, nickel, and uranium. Extraction of metals from U.S. saline aqueous, emphasizing saline, sources is explored as an alternative to hardrock ore mining. Potential aqueous sources include seawater, desalination brines, oil- and gas-produced waters, geothermal aquifers, and acid mine drainage, among others. A feasibility assessment reveals opportunities for recovery of lithium, strontium, magnesium, and several REEs from select sources, in quantities significant for U.S. manufacturing and for reduction of U.S. reliance on international supply chains. This is a conservative assessment given that water quality data are lacking for a significant number of critical metals in certain sources. The technology landscape for extraction and recovery of critical metals from aqueous sources is explored, identifying relevant processes along with knowledge gaps. Our analysis indicates that aqueous mining would result in much lower environmental impacts on water, air, and land than ore mining. Preliminary assessments of the economics and energy consumption of recovery show potential for recovery of critical metals.

Molybdenite is the world’s principal source of rhenium (Re), a critical element in multiple high-tech applications. However, the Re contents in molybdenite vary by orders of magnitude on scales ranging from single grains to whole deposits. In order to better understand the systematics of this variation and what geochemical factors control molybdenite Re concentration, and hence overall Re resources, we examine global patterns in molybdenite Re contents through a compilation of > 3000 measurements of Re in molybdenite from > 700 mainly ore-bearing moderate- to high-temperature hydrothermal systems of different types. Our results are similar to but expand on those of earlier studies. Rhenium concentration in molybdenite has a lognormal distribution and varies systematically with type of geologic system, intrusive lithology, and Mo grade. The lowest-Re molybdenite occurs in greisens (geometric mean 1 ppm ± a multiplicative standard deviation of 9), quartz vein-hosted W-Sn deposits (2 ± 5 ppm), unmineralized granites and granodiorites (12 ± 8 ppm), intrusion-related deposits (24 ± 8 ppm), and porphyry W-Sn deposits (16 ± 11 ppm). Rhenium is most enriched in molybdenites from volcanic sublimates (23,800 ± 5 ppm), with skarn Fe and Au (560 ± 5 ppm and 540 ± 3 ppm respectively) and porphyry Cu and Cu-Au deposits next (470 ± 4 and 430 ± 7 ppm respectively). Among porphyries, skarns, and quartz vein-hosted deposits, Re is most highly concentrated in molybdenites from Cu and Au systems and its concentration decreases systematically through Cu-Mo, Mo, Sn, and W deposits. In nearly all cases, molybdenites from systems associated with intermediate igneous rocks contain more Re than molybdenites from systems of the same type with more felsic rock associations. The disparity between Re contents of molybdenite in felsic and intermediate systems is largest for porphyries, quartz vein-hosted, and skarn deposits and is near zero for subeconomic or barren granite and granodiorite Mo systems; felsic intrusion-related deposits have slightly higher molybdenite Re than their equivalents associated with intermediate intrusions. In most systems, molybdenite Re content does not correlate with metal grade, but may have an inverse correlation with Au grade in intrusion-related deposits (based on a small number of data points) and does exhibit a strong inverse correlation with deposit Mo grade. Dilution of Re through larger amounts (higher deposit grades) of molybdenite explains about 40% of this correlation, but the relative enrichment of Re in molybdenite from low-Mo deposits must also reflect some selective enrichment of Re/Mo in porphyry Cu systems compared to porphyry Mo systems. We found no evidence for secular increase or other systematic temporal variation in molybdenite Re content. The data regarding the use of molybdenite Re content as a proxy for mantle influence are ambiguous. Nearly all observed empirical correlations can be traced back to differences in redox state and sulfide concentration, the two geochemical factors identified here and by previous experimental work as the controlling influences on Re mobility under hydrothermal conditions. Hydrothermal systems with reducing conditions (W- and Sn-rich) tend to have low molybdenite Re even though compiled whole-rock data indicate that their source rocks have as much or more Re as those of more oxidized systems (e.g., Cu-rich). Vapor-phase exsolution, crustal assimilation, and mixing with external fluids may all enrich molybdenite Re concentrations in individual deposits and deposit types, but their extent and importance in overall hydrothermal concentration of Re is uncertain. Thus, it appears that the available molybdenite Re resource in an ore deposit largely depends on how the deposit’s redox and sulfidation conditions have varied over time and space during the timespan of hydrothermal activity. Oxidized, high-sulfide conditions tend to concentrate Re in molybdenite, whereas reducing conditions tend to leave Re dispersed at low concentrations in the bulk rock.

Coarse muscovite veins and alteration occur in porphyry copper and porphyry molybdenum-copper systems within the Laramide arc in Arizona, as well as at the Yerington district in Nevada. This work describes coarse muscovite in veins and altered wall rock in porphyry systems in this region and documents mineral assemblages, mineral compositions, spatial and temporal relationships, and hydrogen isotopic compositions. Coarse hydrothermal muscovite is documented in the roots of porphyry Cu +/- Mo systems, as well as in and above the ore bodies in porphyry Mo-Cu systems, and it is compared to coarse hydrothermal muscovite (greisen) in lode Sn-W-Mo systems. Basin and Range extension has exposed coarse hydrothermal muscovite in several Laramide and Jurassic porphyry Cu (+/- Mo) systems, at paleodepths of 3 to 12 km: Miami-Inspiration, Sierrita-Esperanza, Copper Basin (Crown King), Granite Mountain (roots of the Ray porphyry system), Gunnison (Texas Canyon stock), Grayback (Kelvin-Riverside district), Sycamore Canyon, the New Cornelia mine (Ajo district), and two systems in the Yerington district. Muscovite is the dominant mica in these coarse muscovite veins and associated alteration, with common K-feldspar and albite (An(00-)(06)), common accessory hematite, rutile, pyrite, and apatite, and rare accessory chalcopyrite, fluorite, molybdenite, wolframite, and scheelite. Coarse hydrothermal muscovite yields delta D compositions that suggest formation from fluids that are dominantly magmatic-hydrothermal in origin. Whole-rock compositions of coarse hydrothermal muscovite show common gains in K and loss of Ca +/- Na. Coarse muscovite veins and alteration in porphyry copper systems postdate mineralized potassic veins and form too deeply to overlap with shallower acidic forms of alteration (sericitic, advanced argillic). Variation in mineral assemblage, mineral compositions, and mineralization of coarse hydrothermal muscovite correlate with the composition of Laramide stocks. Porphyry Mo-Cu systems contain coarse muscovite alteration assemblages with the highest mineral diversity and trace-element enrichment. Coarse muscovite veins and alteration in porphyry Mo-Cu systems related to stocks ranging from quartz monzonite to granite in composition form at shallower paleodepths and occur within and above the associated orebodies. In contrast, coarse muscovite veins and alteration associated with subalkaline porphyry copper systems occur at deeper levels, in some cases overlapping with the bottom of potassic alteration and the ore body but extending well into the roots of the system in the underlying granitoid cupola. In these latter systems, zones of coarse muscovite alteration typically are poorly mineralized and mineral assemblages are less varied. These characteristics suggest that coarse muscovite-forming fluids are predominately of magmatic-hydrothermal origin and exsolved from late-stage, fractionated magmas of the larger pluton that sourced porphyry stocks and dikes responsible for porphyry copper mineralization. In some instances, however, the exposed coarse muscovite alteration is associated with a petrologically unrelated, commonly more felsic, later intrusion, rather than being related to late exsolution of fluid from the same crystallizing stock or batholith.