The data included here were used to evaluate the prospectivity for lithium in brines of playas of the western part of the Basin and Range Physiographic Province of the United States. Prospectivity is derived from the mappable criteria used in the descriptive deposit model published by Bradley and others (2013) and focused mainly from the remote sensing point of view. The playas in the study area have been ranked according to size (compared to Clayton Valley, the only area where lithium from brines is being produced in the country), the presence and abundance of source rocks, vegetation (as an indicator of water), reported prospects, and remote sensing data. The remote sensing products used are from data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor because it has regional coverage not available with other sensors.

This data release provides the descriptions of approximately 20 U.S. sites that include mineral regions, mines, and mineral occurrences (deposits and prospects) that contain enrichments of lithium (Li). This release includes sites that have a contained resource and (or) past production of lithium metal greater than 15,000 metric tons. Sites in this database occur in Arkansas, California, Nevada, North Carolina, and Utah. There are several deposits that were not included in the database because they did not meet the cutoff requirement, and those occur in Arizona, Colorado, the New England area, New Mexico, South Dakota, and Wyoming. In the United States, lithium was first mined from pegmatite orebodies in South Dakota in the late 1800s. The Kings Mountain pegmatite belt of North Carolina also had significant production from pegmatites, and the area may still contain as much as 750 million metric tons (Mt) of ore containing 5 Mt lithium metal (Kesler and others, 2012). In 2018, U.S. production of lithium was restricted to a single lithium-brine mining operation in Nevada. In 2018, the U.S. had a net import reliance as a percentage of apparent consumption of more than 50 percent for lithium (U.S. Geological Survey, 2019). The U.S. is not a significant producer of lithium, so the commodity is mainly imported from Chile and Argentina to meet consumer demand. Lithium is necessary for strategic, consumer, and commercial applications. The primary uses for lithium are in batteries, ceramics, glass, metallurgy, pharmaceuticals, and polymers (U.S. Geological Survey, 2019). Lithium has excellent electrical conductivity and low density (lithium metal will float on water), making it an ideal component for battery manufacturing. Lithium is traded in three primary forms: mineral concentrates, mineral compounds (from brines), and refined metal (electrolysis from lithium chloride). Lithium mineralogy is diverse; it occurs in a variety of pegmatite minerals such as spodumene, lepidolite, amblygonite, and in the clay mineral hectorite. Current global production of lithium is dominated by pegmatite and closed-basin brine deposits, but there are significant resources in lithium-bearing clay minerals, oilfield brines, and geothermal brines (Bradley and others, 2017). The entries and descriptions in the database were derived from published papers, reports, data, and internet documents representing a variety of sources, including geologic and exploration studies described in State, Federal, and industry reports. Resources extracted from older sources might not be compliant with current rules and guidelines in minerals industry standards such as National Instrument 43-101 (NI 43-101) or the Joint Ore Reserves Committee Code (JORC Code). The inclusion of a particular lithium mineral deposit in this database is not meant to imply that the deposit is currently economic. Rather, these deposits were included to capture the characteristics of the larger lithium deposits in the United States, which are diverse in their geology and resource potential. Inclusion of material in the database is for descriptive purposes only and does not imply endorsement by the U.S. Government. The authors welcome additional published information in order to continually update and refine this dataset. Bradley, D.C., Stillings, L.L., Jaskula, B.W., Munk, LeeAnn, and McCauley, A.D., 2017, Lithium, chap. K of Schulz, K.J., DeYoung, J.H., Jr., Seal, R.R., II, and Bradley, D.C., eds., Critical mineral resources of the United States—Economic and environmental geology and prospects for future supply: U.S. Geological Survey Professional Paper 1802, p. K1–K21, https://doi.org/10.3133/pp1802K. Kesler, S.E., Gruber, P.W., Medina, P.A., Keoleian, G.A., Everson, M.P., and Wallington, T.J., 2012, Global lithium resources—relative importance of pegmatite, brine and other deposits: Ore Geology Reviews, v. 48, October ed., p. 55—69. U.S. Geological Survey, 2019, Mineral commodity summaries 2019:

Presented are major element and lithium concentrations of minerals from the Salton Sea Geothermal Field (SSGF), located in the Imperial Valley, California. With a recent increase in demand for lithium, the area is now being studied as a source of geothermal brine for lithium extraction. This study was performed to help quantify lithium storage in the SSGF brine and surrounding minerals. Rocks and brines sampled in this study are from surface rhyolitic domes on the South Eastern shore of the Salton Sea, the sedimentary and evaporitic rocks in the Durmid Hills, rhyolitic drill clippings previously studied by Schmitt & Hulen, commercial drill wells, and CA State 2-14 well.

Mineral groups identified through automated analysis of remote sensing data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to generate a map showing the type and spatial distribution of hydrothermal alteration, other exposed mineral groups, and green vegetation across the southwestern conterminous United States. Boolean algebra was used to combine mineral groups identified through analysis of visible, near-infrared, and shortwave-infrared ASTER data into attributed alteration types and mineral classes based on common mineralogical definitions of such types and the minerals present within the mineral groups. Alteration types modeled in this way can be stratified relative to acid producing and neutralizing potential to aid in geoenvironmental watershed studies. This mapping was performed in support of multidisciplinary studies involving the predictive modeling of mineral deposit occurrence and geochemical environments at watershed to regional scales. These studies seek to determine the relative effects of mining and non-anthropogenic hydrothermal alteration on watershed surface water geochemistry and faunal populations. The presence or absence of hydrothermally-altered rocks and (or) specific mineral groups can be used to model the favorability of occurrence of certain types of mineral deposits, and aid in the delineation of permissive tracts for these deposits. These data were used as a data source for the U.S. Geological Survey (USGS) Sagebrush Mineral-Resource Assessment (SaMiRA). This map, in ERDAS Imagine (.img) format, has been attributed by pixel value with material identification data that can be queried in most image processing and GIS software packages. Three files are included with this product: file with .img extension contains thematic image attributes and geographic projection data, file with .ige extension contains the raster data, and the file with .rrd extension includes pyramid data for fast display.

Mineral groups identified through automated analysis of remote sensing data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to generate a map showing the type and spatial distribution of hydrothermal alteration, other exposed mineral groups, and green vegetation across the southwestern conterminous United States. Boolean algebra was used to combine mineral groups identified through analysis of visible, near-infrared, and shortwave-infrared ASTER data into attributed alteration types and mineral classes based on common mineralogical definitions of such types and the minerals present within the mineral groups. Alteration types modeled in this way can be stratified relative to acid producing and neutralizing potential to aid in geoenvironmental watershed studies. This mapping was performed in support of multidisciplinary studies involving the predictive modeling of mineral deposit occurrence and geochemical environments at watershed to regional scales. These studies seek to determine the relative effects of mining and non-anthropogenic hydrothermal alteration on watershed surface water geochemistry and faunal populations. The presence or absence of hydrothermally-altered rocks and (or) specific mineral groups can be used to model the favorability of occurrence of certain types of mineral deposits, and aid in the delineation of permissive tracts for these deposits. These data were used as a data source for the U.S. Geological Survey (USGS) Sagebrush Mineral-Resource Assessment (SaMiRA). This map, in ERDAS Imagine (.img) format, has been attributed by pixel value with material identification data that can be queried in most image processing and GIS software packages. Three files are included with this product: file with .img extension contains thematic image attributes and geographic projection data, file with .ige extension contains the raster data, and the file with .rrd extension includes pyramid data for fast display.

Mineral groups identified through automated analysis of remote sensing data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to generate a map showing the type and spatial distribution of hydrothermal alteration, other exposed mineral groups, and green vegetation across the southwestern conterminous United States. Boolean algebra was used to combine mineral groups identified through analysis of visible, near-infrared, and shortwave-infrared ASTER data into attributed alteration types and mineral classes based on common mineralogical definitions of such types and the minerals present within the mineral groups. Alteration types modeled in this way can be stratified relative to acid producing and neutralizing potential to aid in geoenvironmental watershed studies. This mapping was performed in support of multidisciplinary studies involving the predictive modeling of mineral deposit occurrence and geochemical environments at watershed to regional scales. These studies seek to determine the relative effects of mining and non-anthropogenic hydrothermal alteration on watershed surface water geochemistry and faunal populations. The presence or absence of hydrothermally-altered rocks and (or) specific mineral groups can be used to model the favorability of occurrence of certain types of mineral deposits, and aid in the delineation of permissive tracts for these deposits. These data were used as a data source for the U.S. Geological Survey (USGS) Sagebrush Mineral-Resource Assessment (SaMiRA). This map, in ERDAS Imagine (.img) format, has been attributed by pixel value with material identification data that can be queried in most image processing and GIS software packages. Three files are included with this product: file with .img extension contains thematic image attributes and geographic projection data, file with .ige extension contains the raster data, and the file with .rrd extension includes pyramid data for fast display.

The product data are six statistics that were estimated for the chemical concentration of lithium in the soil C horizon of the conterminous United States. The estimates are made at 9998 locations that are uniformly distributed across the conterminous United States. The six statistics are the mean for the isometric log-ratio transform of the concentrations, the equivalent mean for the concentrations, the standard deviation for the isometric log-ratio transform of the concentrations, the probability of exceeding a concentration of 55 milligrams per kilogram, the 0.95 quantile for the isometric log-ratio transform of the concentrations, and the equivalent 0.95 quantile for the concentrations. Each statistic may be used to generate a statistical map that shows an attribute of the distribution of lithium concentration.

The product data are six statistics that were estimated for the chemical concentration of lithium in the soil C horizon of the conterminous United States. The estimates are made at 9998 locations that are uniformly distributed across the conterminous United States. The six statistics are the mean for the isometric log-ratio transform of the concentrations, the equivalent mean for the concentrations, the standard deviation for the isometric log-ratio transform of the concentrations, the probability of exceeding a concentration of 55 milligrams per kilogram, the 0.95 quantile for the isometric log-ratio transform of the concentrations, and the equivalent 0.95 quantile for the concentrations. Each statistic may be used to generate a statistical map that shows an attribute of the distribution of lithium concentration.

This data release provides the U.S. Geological Survey (USGS) Spectral Library Version 7 and all related documents. The library contains spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns). Laboratory samples of specific minerals, plants, chemical compounds, and man-made materials were measured. In many cases, samples were purified, so that unique spectral features of a material can be related to its chemical structure. These spectro-chemical links are important for interpreting remotely sensed data collected in the field or from an aircraft or spacecraft. This library also contains physically-constructed as well as mathematically-computed mixtures. Measurements of rocks, soils, and natural mixtures of minerals have also been made with laboratory and field spectrometers. Spectra of plant components and vegetation plots, comprising many plant types and species with varying backgrounds, are also in this library. Measurements by airborne spectrometers are included for forested vegetation plots, in which the trees are too tall for measurement by a field spectrometer. The related U.S. Geological Survey Data Series publication, "USGS Spectral Library Version 7", describes the instruments used, metadata descriptions of spectra and samples, and possible artifacts in the spectral measurements (Kokaly and others, 2017). Four different spectrometer types were used to measure spectra in the library: (1) Beckman™ 5270 covering the spectral range 0.2 to 3 µm, (2) standard, high resolution (hi-res), and high-resolution Next Generation (hi-resNG) models of ASD field portable spectrometers covering the range from 0.35 to 2.5 µm, (3) Nicolet™ Fourier Transform Infra-Red (FTIR) interferometer spectrometers covering the range from about 1.12 to 216 µm, and (4) the NASA Airborne Visible/Infra-Red Imaging Spectrometer AVIRIS, covering the range 0.37 to 2.5 µm. Two fundamental spectrometer characteristics significant for interpreting and utilizing spectral measurements are sampling position (the wavelength position of each spectrometer channel) and bandpass (a parameter describing the wavelength interval over which each channel in a spectrometer is sensitive). Bandpass is typically reported as the Full Width at Half Maximum (FWHM) response at each channel (in wavelength units, for example nm or micron). The linked publication (Kokaly and others, 2017), includes a comparison plot of the various spectrometers used to measure the data in this release. Data for the sampling positions and the bandpass values (for each channel in the spectrometers) are included in this data release. These data are in the SPECPR files, as separate data records, and in the American Standard Code for Information Interchange (ASCII) text files, as separate files for wavelength and bandpass. Spectra are provided in files of ASCII text format (files with a .txt file extension). In the ASCII files, deleted channels (bad bands) are indicated by a value of -1.23e34. Metadata descriptions of samples, field areas, spectral measurements, and results from supporting material analyses – such as XRD – are provided in HyperText Markup Language HTML formatted ASCII text files (files with .html file extension). In addition, Graphics Interchange Format (GIF) images of plots of spectra are provided. For each spectrum a plot with wavelength in microns on the x-axis is provided. For spectra measured on the Nicolet spectrometer, an additional GIF image with wavenumber on the x-axis is provided. Data are also provided in SPECtrum Processing Routines (SPECPR) format (Clark, 1993) which packages spectra and associated metadata descriptions into a single file (see the linked publication, Kokaly and others, 2017, for additional details on the SPECPR format and freely-available software than can be used to read files in SPECPR format). The data measured on the source spectrometers are