This data set compiles the major and trace element chemistry of rock samples collected by the U.S. Geological Survey (USGS) at Bokan Mountain, located in the southern part of Prince of Wales Island, southeastern Alaska. Bokan Mountain was formed by an Early Jurassic peralkaline igneous complex that intruded into lower Paleozoic rocks of the Alexander terrane of southeast Alaska. The pluton and surrounding country rocks host numerous mineral deposits and occurrences, including heavy rare earth element (HREE)-rich pegmatites and felsic dikes, as well as mineral deposits rich in uranium, thorium, HREE, and fluorine. The Ross-Adams mine on Bokan Mountain exploited a uranium-thorium deposit intermittently from the late 1950s to 1971, and remains the only uranium producer in Alaska. Recent exploration by Ucore Rare Metals Inc. (http://ucore.com/) at Bokan Mountain has focused on the Dotson and I and L Zones, which together form a 2.5-km-long, 50 m-wide zone of thin felsic dikes and pegmatites (each rarely more than 2-m-wide) that are enriched in rare earth elements (REE). Ucore Rare Metals has reported an inferred resource for the combined zones as 5.275 million metric tons of ore at 0.654 percent total REE oxides, using a cutoff of 0.4 percent total REE oxides; about 40 percent of the total REE oxides in these dikes and pegmatites are the HREE (http://ucore.com/Ucore_43-101.pdf). This data release provides the analytical results of 153 rock hand samples collected by USGS geologists during site visits to Bokan Mountain in 2010, 2011, and field studies during 2014. The samples represent a variety of rock types associated with the Bokan Mountain igneous complex, including mineral deposits, prospects and occurrences, along with examples of unaltered intrusions of the pluton. The samples were analyzed for 55 major and trace elements using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS) and also analyzed for major elements using wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This data set is provided for future use in geologic, exploration, and environmental background studies of Bokan Mountain and its mineral deposits.

This data release presents the major and trace element chemistry of rock samples collected by the U.S. Geological Survey (USGS) from trenches, channel cuts, test pits, and surface exposures of the Dotson and I and L Zone rare earth element deposits at Bokan Mountain, located in the southern part of Prince of Wales Island, southeastern Alaska. Bokan Mountain was formed by an Early Jurassic peralkaline igneous complex that intruded into lower Paleozoic rocks of the Alexander terrane of southeast Alaska. The pluton and surrounding country rocks host numerous mineral deposits and occurrences, including heavy rare earth element (HREE)-rich pegmatites and felsic dikes, as well as mineral deposits rich in uranium, thorium, HREE, and fluorine. Recent exploration by Ucore Rare Metals Inc. (http://ucore.com/) at Bokan Mountain has focused on the Dotson and I and L Zones, which together form a 2.5-km-long, 50 m-wide zone of thin felsic dikes and pegmatites (each rarely more than 2-m-wide individually) that are enriched in rare earth elements (REE). Ucore Rare Metals has reported an indicated resource of 4.788 million metric tons of ore at 0.602 percent total REE oxides and an inferred resource of 1.050 million metric tons of ore at 0.603 percent total REE oxides, using a cutoff of 0.4 percent total REE oxides; about 40 percent of the total REE oxides in these dikes and pegmatites are the HREE (Ucore Rare Metals, 2020). There is also potential for the production of by-product Nb, Zr, and Ti. This data release provides the analytical results of 42 rock samples collected by the author during a site visit to Bokan Mountain in August 2014. The samples represent a complete transect along the entire length of the combined I and L and Dotson Zones from the margin of the pluton to tidewater in Kendrick Bay. They provide a measure of the REE abundances and their variation throughout the deposit as well as material for detailed isotopic and mineral chemistry studies (Taylor and others, 2016, 2017). The samples were analyzed for 57 major and trace elements using inductively coupled plasma-atomic emission spectrometry (ICP-AES), inductively coupled plasma-mass spectrometry (ICP-MS and ICP-MSREE), and inductively coupled plasma-optical emission spectrometry for zirconium (ICPOES). The samples were also analyzed for major elements using wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This data set is provided for future use in geologic, exploration, and environmental background studies of the Dotson and I and L Zone deposits. References listed here provide geologic context and additional descriptions on the geologic features represented by the rock samples: Barker, J.C., and Van Gosen, B.S., 2012, Alaska's rare earth deposits and resource potential: Mining Engineering, v. 64, no. 1, p. 20-32. Dostal, J., Karl, S.M., Keppie, J.D., Kontak, D.J., Shellnutt, J.G., 2013, Bokan Mountain peralkaline granitic complex, Alexander terrane (southeastern Alaska)-Evidence for Early Jurassic rifting prior to accretion with North America: Canadian Journal of Earth Sciences, v. 50, 678-691. Dostal, Jaroslav, Kontak, D.J., and Karl, S.M., 2014, The Early Jurassic Bokan Mountain peralkaline granitic complex (southeastern Alaska)-Geochemistry, petrogenesis and rare-metal mineralization: Lithos, v. 202-203, p. 395-412. Dostal, Jaroslav, and Shellnutt, J.G., 2016, Origin of peralkaline granites of the Jurassic Bokan Mountain complex (southeastern Alaska) hosting rare metal mineralization: International Geology Review, v. 58, no. 1, p. 1-13. Long, K.R., Van Gosen, B.S., Foley, N.K., and Cordier, David, 2010, The principal rare earth elements deposits of the United States-A summary of domestic deposits and a global perspective: U.S. Geological Survey Scientific Investigations Report 2010-5220, p. 28-34. Available at http://pubs.usgs.gov/sir/2010/5220/. MacKevett, E.M., Jr., 1963, Geology and ore deposits of the Bokan Mountain uranium-thorium area, southeastern

This data release presents the major and trace element chemistry of rock samples collected by the U.S. Geological Survey (USGS) from trenches, channel cuts, test pits, and surface exposures of the Dotson and I and L Zone rare earth element deposits at Bokan Mountain, located in the southern part of Prince of Wales Island, southeastern Alaska. Bokan Mountain was formed by an Early Jurassic peralkaline igneous complex that intruded into lower Paleozoic rocks of the Alexander terrane of southeast Alaska. The pluton and surrounding country rocks host numerous mineral deposits and occurrences, including heavy rare earth element (HREE)-rich pegmatites and felsic dikes, as well as mineral deposits rich in uranium, thorium, HREE, and fluorine. Recent exploration by Ucore Rare Metals Inc. (http://ucore.com/) at Bokan Mountain has focused on the Dotson and I and L Zones, which together form a 2.5-km-long, 50 m-wide zone of thin felsic dikes and pegmatites (each rarely more than 2-m-wide individually) that are enriched in rare earth elements (REE). Ucore Rare Metals has reported an indicated resource of 4.788 million metric tons of ore at 0.602 percent total REE oxides and an inferred resource of 1.050 million metric tons of ore at 0.603 percent total REE oxides, using a cutoff of 0.4 percent total REE oxides; about 40 percent of the total REE oxides in these dikes and pegmatites are the HREE (Ucore Rare Metals, 2020). There is also potential for the production of by-product Nb, Zr, and Ti. This data release provides the analytical results of 42 rock samples collected by the author during a site visit to Bokan Mountain in August 2014. The samples represent a complete transect along the entire length of the combined I and L and Dotson Zones from the margin of the pluton to tidewater in Kendrick Bay. They provide a measure of the REE abundances and their variation throughout the deposit as well as material for detailed isotopic and mineral chemistry studies (Taylor and others, 2016, 2017). The samples were analyzed for 57 major and trace elements using inductively coupled plasma-atomic emission spectrometry (ICP-AES), inductively coupled plasma-mass spectrometry (ICP-MS and ICP-MSREE), and inductively coupled plasma-optical emission spectrometry for zirconium (ICPOES). The samples were also analyzed for major elements using wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This data set is provided for future use in geologic, exploration, and environmental background studies of the Dotson and I and L Zone deposits. References listed here provide geologic context and additional descriptions on the geologic features represented by the rock samples: Barker, J.C., and Van Gosen, B.S., 2012, Alaska's rare earth deposits and resource potential: Mining Engineering, v. 64, no. 1, p. 20-32. Dostal, J., Karl, S.M., Keppie, J.D., Kontak, D.J., Shellnutt, J.G., 2013, Bokan Mountain peralkaline granitic complex, Alexander terrane (southeastern Alaska)-Evidence for Early Jurassic rifting prior to accretion with North America: Canadian Journal of Earth Sciences, v. 50, 678-691. Dostal, Jaroslav, Kontak, D.J., and Karl, S.M., 2014, The Early Jurassic Bokan Mountain peralkaline granitic complex (southeastern Alaska)-Geochemistry, petrogenesis and rare-metal mineralization: Lithos, v. 202-203, p. 395-412. Dostal, Jaroslav, and Shellnutt, J.G., 2016, Origin of peralkaline granites of the Jurassic Bokan Mountain complex (southeastern Alaska) hosting rare metal mineralization: International Geology Review, v. 58, no. 1, p. 1-13. Long, K.R., Van Gosen, B.S., Foley, N.K., and Cordier, David, 2010, The principal rare earth elements deposits of the United States-A summary of domestic deposits and a global perspective: U.S. Geological Survey Scientific Investigations Report 2010-5220, p. 28-34. Available at http://pubs.usgs.gov/sir/2010/5220/. MacKevett, E.M., Jr., 1963, Geology and ore deposits of the Bokan Mountain uranium-thorium area, southeastern

This data release presents the major and trace element chemistry of rock samples collected by the U.S. Geological Survey (USGS) from surface exposures of the Dora Bay igneous complex (DBIC), located in the southern part of Prince of Wales Island, southeastern Alaska. The DBIC is Early Jurassic in age (Bala and others, 2014) and is U-Th-heavy rare earth element (HREE)-enriched like the Bokan Mountain intrusive complex 30 km to the south (Philpotts and others 1998; Dostal and others, 2011; Taylor and others, 2016; 2017). However, the DBIC is significantly less-well-mineralized and is under-explored due to complicated private land status issues. HREE-enriched eudialyte-bearing pegmatites and felsic dikes have been discovered in numerous places within and along the margins of the pluton and extending up to 1 km into the country rocks as well as molybdenite and iron oxide mineral occurrences at its margins (Barker and Mardock, 1990; Philpotts and others, 1993; Taylor and others, 2014). Uncertainty of global REE supply and the subsequent spike in prices in 2008 resulted in renewed exploration at the DBIC by Avalon in 2010 and Sealaska Native Corporation in 2014-2015 (Buckley and Taylor, 2014). The DBIC was included in recent studies by the USGS Mineral Resources Program as part of an effort to understand the distribution of REE resources in the United States. This data release provides the analytical results of 54 rock samples collected by the authors during a site visit to the DBIC in June-July 2015. The samples represent transects along the major exposed ridgelines and outcrops within the complex. They provide a measure of the REE abundances and their variation throughout the complex as well as material for detailed isotopic and mineral chemistry studies. The samples were analyzed for 60 major and trace elements by inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS)after a sodium fusion digestion and for major elements using wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This data set is provided for future use in geologic, exploration, and environmental background studies of the DBIC. References listed here provide geologic context and additional descriptions on the geologic features represented by the rock samples: Bala, S.A., Holm-Denoma, C.S., Neymark, L.A., Taylor, C.D., Pietruszka, A.J., and Driscoll, R.L., 2014, U-Pb zircon ages and mineralogy of the Dora Bay intrusive complex and heavy REE-bearing pegmatite dikes: Geological Society of America Abstracts with Programs, v. 46, no. 6, p. 782, Abstract No. 324-11. Barker, J.C., and Mardock, Cheryl, 1990, Rare-earth element- and yttrium-bearing pegmatite dikes near Dora Bay, southern Prince of Wales Island: U.S. Bureau of Mines Open-File Report 19-90, 41 p. Barker, J.C., and Van Gosen, B.S., 2012, Alaska's rare earth deposits and resource potential: Mining Engineering, v. 64, no. 1, p. 20-32. Buckley, Steve, and Taylor, Cliff, 2014, Mineral potential on Sealaska Corporation Lands, southeast Alaska: Alaska Miner’s Association Biennial Conference on Alaskan Mining, Anchorage, Nov. 3–7, Abstracts of Papers, p. x. Dostal, J., Kontak, D.J., Hanley, J., and Owen, V. 2011. Geological investigation of rare earth element and uranium deposits of the Bokan Mountain Complex, Prince of Wales Island, Southeastern Alaska. U.S. Geological Survey Mineral Resources External Research Report G09AP00039, p. 122. Long, K.R., Van Gosen, B.S., Foley, N.K., and Cordier, David, 2010, The principal rare earth elements deposits of the United States-A summary of domestic deposits and a global perspective: U.S. Geological Survey Scientific Investigations Report 2010-5220, p. 28-34. Available at http://pubs.usgs.gov/sir/2010/5220/. Philpotts, J., Taylor, C.D., Evans, J., and Emsbo, P., 1993, Newly discovered molybdenite occurrences at Dora Bay, Prince of Wales Island, southeast Alaska, and preliminary scanning electron

This data release presents the major and trace element chemistry of rock samples collected by the U.S. Geological Survey (USGS) from surface exposures of the Dora Bay igneous complex (DBIC), located in the southern part of Prince of Wales Island, southeastern Alaska. The DBIC is Early Jurassic in age (Bala and others, 2014) and is U-Th-heavy rare earth element (HREE)-enriched like the Bokan Mountain intrusive complex 30 km to the south (Philpotts and others 1998; Dostal and others, 2011; Taylor and others, 2016; 2017). However, the DBIC is significantly less-well-mineralized and is under-explored due to complicated private land status issues. HREE-enriched eudialyte-bearing pegmatites and felsic dikes have been discovered in numerous places within and along the margins of the pluton and extending up to 1 km into the country rocks as well as molybdenite and iron oxide mineral occurrences at its margins (Barker and Mardock, 1990; Philpotts and others, 1993; Taylor and others, 2014). Uncertainty of global REE supply and the subsequent spike in prices in 2008 resulted in renewed exploration at the DBIC by Avalon in 2010 and Sealaska Native Corporation in 2014-2015 (Buckley and Taylor, 2014). The DBIC was included in recent studies by the USGS Mineral Resources Program as part of an effort to understand the distribution of REE resources in the United States. This data release provides the analytical results of 54 rock samples collected by the authors during a site visit to the DBIC in June-July 2015. The samples represent transects along the major exposed ridgelines and outcrops within the complex. They provide a measure of the REE abundances and their variation throughout the complex as well as material for detailed isotopic and mineral chemistry studies. The samples were analyzed for 60 major and trace elements by inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS)after a sodium fusion digestion and for major elements using wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This data set is provided for future use in geologic, exploration, and environmental background studies of the DBIC. References listed here provide geologic context and additional descriptions on the geologic features represented by the rock samples: Bala, S.A., Holm-Denoma, C.S., Neymark, L.A., Taylor, C.D., Pietruszka, A.J., and Driscoll, R.L., 2014, U-Pb zircon ages and mineralogy of the Dora Bay intrusive complex and heavy REE-bearing pegmatite dikes: Geological Society of America Abstracts with Programs, v. 46, no. 6, p. 782, Abstract No. 324-11. Barker, J.C., and Mardock, Cheryl, 1990, Rare-earth element- and yttrium-bearing pegmatite dikes near Dora Bay, southern Prince of Wales Island: U.S. Bureau of Mines Open-File Report 19-90, 41 p. Barker, J.C., and Van Gosen, B.S., 2012, Alaska's rare earth deposits and resource potential: Mining Engineering, v. 64, no. 1, p. 20-32. Buckley, Steve, and Taylor, Cliff, 2014, Mineral potential on Sealaska Corporation Lands, southeast Alaska: Alaska Miner’s Association Biennial Conference on Alaskan Mining, Anchorage, Nov. 3–7, Abstracts of Papers, p. x. Dostal, J., Kontak, D.J., Hanley, J., and Owen, V. 2011. Geological investigation of rare earth element and uranium deposits of the Bokan Mountain Complex, Prince of Wales Island, Southeastern Alaska. U.S. Geological Survey Mineral Resources External Research Report G09AP00039, p. 122. Long, K.R., Van Gosen, B.S., Foley, N.K., and Cordier, David, 2010, The principal rare earth elements deposits of the United States-A summary of domestic deposits and a global perspective: U.S. Geological Survey Scientific Investigations Report 2010-5220, p. 28-34. Available at http://pubs.usgs.gov/sir/2010/5220/. Philpotts, J., Taylor, C.D., Evans, J., and Emsbo, P., 1993, Newly discovered molybdenite occurrences at Dora Bay, Prince of Wales Island, southeast Alaska, and preliminary scanning electron

This data release is part of a 2016-2019 study on the geology, geochemistry and geochronology of ore systems in the eastern Yukon-Tanana Upland region, Alaska. Whole rock chemistry was conducted on 185 samples, mostly from Au prospects, with lesser samples from porphyry Cu prospects. Geographically, most samples are from gold prospects near the Pogo Au mine and east to Black Mountain in the Big Delta quadrangle. Fewer samples are from prospects in the Eagle and Tanacross Quadrangles. Samples were submitted to the USGS contract laboratory and analyzed for select trace elements and gold. Sixty elements were determined by inductively coupled plasma-optical emission spectroscopy-mass spectroscopy (ICP-OES-MS), sodium peroxide fusion (ICP-60). Gold was determined by lead fusion fire assay.

This data release is part of a 2016-2019 study on the geology, geochemistry and geochronology of ore systems in the eastern Yukon-Tanana Upland region, Alaska. Whole rock chemistry was conducted on 185 samples, mostly from Au prospects, with lesser samples from porphyry Cu prospects. Geographically, most samples are from gold prospects near the Pogo Au mine and east to Black Mountain in the Big Delta quadrangle. Fewer samples are from prospects in the Eagle and Tanacross Quadrangles. Samples were submitted to the USGS contract laboratory and analyzed for select trace elements and gold. Sixty elements were determined by inductively coupled plasma-optical emission spectroscopy-mass spectroscopy (ICP-OES-MS), sodium peroxide fusion (ICP-60). Gold was determined by lead fusion fire assay.

Data for 819 pan concentrated stream-sediment samples, nonmagnetic heavy-mineral concentrate (HMC) samples, and chemical data for 93 of HMC samples. The samples were collected in 2004-2008 as part of a reconnaissance geochemical geological survey of drainage basins mostly in the Taylor Mountains 1:250,000-scale quadrangle in southwestern Alaska. Samples were collected from first- or second-order streams, as shown on USGS 1:63,360-scale maps. The data reported here are from hand lens inspection of the panned concentrate samples in the field, microscopic examination of the non-magnetic fraction of the HMC samples in the lab, and chemical analyses by Inductively Coupled Plasma-Atomic Emission Spectrometry-Mass Spectrometry (ICP-AES-MS) of selected nonmagnetic HMC samples.

Data for 819 pan concentrated stream-sediment samples, nonmagnetic heavy-mineral concentrate (HMC) samples, and chemical data for 93 of HMC samples is presented in data file geology_mineralogy_geochemistry_TaylorMtns_Alaska_Wang.csv. The samples were collected in 2004-2008 as part of a reconnaissance geochemical geological survey of drainage basins mostly in the Taylor Mountains 1:250,000-scale quadrangle in southwestern Alaska. Samples were collected from first- or second-order streams, as shown on USGS 1:63,360-scale maps. The data reported here are from hand lens inspection of the panned concentrate samples in the field, microscopic examination of the non-magnetic fraction of the HMC samples in the lab, and chemical analyses by Inductively Coupled Plasma-Atomic Emission Spectrometry-Mass Spectrometry (ICP-AES-MS) of selected nonmagnetic HMC samples. Details of sample processing and analysis are provided in the supplemental document Supplemental_Info_Methods_Collection_Processing_Analytical.pdf. For citations regarding other analysis and samples collected during the survey see the references provided in supplemental documentation Supplemental_Info_Citations_Related_Datasets.pdf.