This dataset contains results from electron microprobe analyses of cassiterite from the Sullivan Pb-Zn-Ag deposit, British Columbia. These data were collected from two samples and may not reflect the overall variability present at the deposit. An ASCII text file of results is provided in comma-separated by value (csv) format. The file has the name “2019-07-09_Sullivan_Cassiterite”.

This dataset contains results from electron microprobe analyses for expanded and unexpanded vermiculite samples. These data are provide for samples of vermiculite ore, expanded vermiculite insulation, horticultural products, aggregate, and packing materials derived from mines near Enoree, South Carolina; Libby, Montana; Louisa, Virginia; Palabora, South Africa; Jiangsu, China; and Llano, Texas. An ASCII text file of results is provided in comma-separated by value (csv) format. The file has the name “vermiculite_probe_microanalyses_data.csv”.

This dataset contains results from electron microprobe analyses for expanded and unexpanded vermiculite samples. These data are provide for samples of vermiculite ore, expanded vermiculite insulation, horticultural products, aggregate, and packing materials derived from mines near Enoree, South Carolina; Libby, Montana; Louisa, Virginia; Palabora, South Africa; Jiangsu, China; and Llano, Texas. An ASCII text file of results is provided in comma-separated by value (csv) format. The file has the name “vermiculite_probe_microanalyses_data.csv”.

The exploration for porphyry deposits in some parts of Alaska may require unconventional exploration geochemical methods, depending on type of cover. The Taurus deposit and others in the region are mostly concealed by residual soils that in part include ash and loess, and therefore traditional stream sediment samples typically contain subdued geochemical signatures. Indicator mineral studies include collection of stream sediment samples and analysis using automated SEM mineralogical techniques. The presence of select minerals in the stream sediments may indicate mineralization. In addition, the chemistry of specific minerals may be used to distinguish a hydrothermal origin as opposed to others, and include apatite, rutile, and titanite. The electron probe data in this data release were collected for apatite, rutile, and titanite by personnel of the Geology, Geophysics, and Geochemistry Science Center in Denver, Colorado, for the U.S. Geological Survey (USGS) Mineral Resources Program (MRP). Appreciable differences in chemistry were noted for these minerals in mineralized rock and stream sediment samples draining these rocks compared to sediment samples away from mineralization.

The exploration for porphyry deposits in some parts of Alaska may require unconventional exploration geochemical methods, depending on type of cover. The Taurus deposit and others in the region are mostly concealed by residual soils that in part include ash and loess, and therefore traditional stream sediment samples typically contain subdued geochemical signatures. Indicator mineral studies include collection of stream sediment samples and analysis using automated SEM mineralogical techniques. The presence of select minerals in the stream sediments may indicate mineralization. In addition, the chemistry of specific minerals may be used to distinguish a hydrothermal origin as opposed to others, and include apatite, rutile, and titanite. The electron probe data in this data release were collected for apatite, rutile, and titanite by personnel of the Geology, Geophysics, and Geochemistry Science Center in Denver, Colorado, for the U.S. Geological Survey (USGS) Mineral Resources Program (MRP). Appreciable differences in chemistry were noted for these minerals in mineralized rock and stream sediment samples draining these rocks compared to sediment samples away from mineralization.

Cassiterite (SnO2), a main ore mineral in tin deposits, was collected by multiple Russian geologists or obtained from museum collections in both the USA and Russia and dated at the U.S. Geological Survey. The dated samples represent four different mining districts spanning the entire country from the village of Pitkäranta in the west (31° E Longitude) to the Merekskoe Deposit in the Russian Far East (134°E Longitude). The samples were recovered from a variety of host deposit types that range from the Proterozoic to Phanerozoic. Cassiterite (in the form of mounted loose grains) was prepared and analyzed for direct age dating on a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system at the USGS in Denver, Colorado from February 2017 to October 2019. This data supports the following associated publication: Neymark, L.A., Larin, A.M., and Moscati, R.J., 2021, Pb-Pb and U-Pb dating of cassiterite by in situ LA-ICPMS: Examples spanning ~1.85 Ga to ~100 Ma deposits in Russia and implications for dating Proterozoic to Phanerozoic tin deposits, Minerals.

Cassiterite (SnO2), a main ore mineral in tin deposits, was collected by multiple Russian geologists or obtained from museum collections in both the USA and Russia and dated at the U.S. Geological Survey. The dated samples represent four different mining districts spanning the entire country from the village of Pitkäranta in the west (31° E Longitude) to the Merekskoe Deposit in the Russian Far East (134°E Longitude). The samples were recovered from a variety of host deposit types that range from the Proterozoic to Phanerozoic. Cassiterite (in the form of mounted loose grains) was prepared and analyzed for direct age dating on a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system at the USGS in Denver, Colorado from February 2017 to October 2019. This data supports the following associated publication: Neymark, L.A., Larin, A.M., and Moscati, R.J., 2021, Pb-Pb and U-Pb dating of cassiterite by in situ LA-ICPMS: Examples spanning ~1.85 Ga to ~100 Ma deposits in Russia and implications for dating Proterozoic to Phanerozoic tin deposits, Minerals.

This data release provides electron microprobe analyses of ore minerals from the Copperwood sediment-hosted stratiform copper deposit in the Upper Peninsula of Michigan. The minerals include bornite, chalcocite, native copper, native silver, and pyrite. Minerals were analyzed for Ag, As, Co, Cu, Fe, Hg, Ni, Pb, S, Sb, and Zn. Results with acceptable totals that lie between 98.5 and 101.5% show that these minerals are stoichiometric, with very limited substitution of other elements. The Copperwood copper deposit is a sediment-hosted stratiform copper deposit in the Presque Isle Syncline of the Upper Peninsula of Michigan. The Lower Copper Bearing Sequence has a 2018 mineral resource estimate of 42.2 million metric tons (Mt) of measured plus indicated mineral resources at an average grade of 1.60% Cu and 3.84 g/t Ag. The measured plus indicated mineral resource in the Upper Copper Bearing Sequence is estimated to be 7.1 Mt at an average grade of 1.21% Cu and 3.26 g/t Ag (Gignac, 2018). The mineral reserves for the Copperwood Project are estimated at 25.4 Mt at an average grade of 1.43% Cu and 3.83 g/t Ag (Gignac, 2018).

This data release provides electron microprobe analyses of ore minerals from the Copperwood sediment-hosted stratiform copper deposit in the Upper Peninsula of Michigan. The minerals include bornite, chalcocite, native copper, native silver, and pyrite. Minerals were analyzed for Ag, As, Co, Cu, Fe, Hg, Ni, Pb, S, Sb, and Zn. Results with acceptable totals that lie between 98.5 and 101.5% show that these minerals are stoichiometric, with very limited substitution of other elements. The Copperwood copper deposit is a sediment-hosted stratiform copper deposit in the Presque Isle Syncline of the Upper Peninsula of Michigan. The Lower Copper Bearing Sequence has a 2018 mineral resource estimate of 42.2 million metric tons (Mt) of measured plus indicated mineral resources at an average grade of 1.60% Cu and 3.84 g/t Ag. The measured plus indicated mineral resource in the Upper Copper Bearing Sequence is estimated to be 7.1 Mt at an average grade of 1.21% Cu and 3.26 g/t Ag (Gignac, 2018). The mineral reserves for the Copperwood Project are estimated at 25.4 Mt at an average grade of 1.43% Cu and 3.83 g/t Ag (Gignac, 2018).

This dataset contains reflectance and transmission spectra of unexpanded and expanded vermiculite ore, and handpicked flakes of phlogopite, hydrobiotite, and vermiculite. These samples were collected from mines near Enoree, South Carolina; Libby, Montana; Louisa, Virginia; Palabora, Llano, Texas; and South Africa. Spectra are identified as either reflectance or transmission in the alphanumeric file names and correlate to specpr record numbers designated in the manuscript figures in which they are shown. These transmission spectra were converted to absorbance in many of the figures. Spectra of talc, fibrous richterite amphibole, and serpentine are from well characterized samples from Feiser Mine, Ruby Mountains, Montana; Libby, Montana; and a NIOSH chrysotile standard (CH29) respectively. The talc sample is described in the U.S. Geological Survey Spectral Library (Kokaly and others, 2017). Some vermiculite samples were K-exchanged to facilitate spectral comparisons.