The Tok project area is adjacent to the Delta mineral belt volcanogenic massive-sulfide (VMS) district, the Peak gold-silver-copper skarn, and structurally controlled gold and antimony mineralization in the Stibnite Creek and White Gold areas. The project area also includes the Noah prospect, an intrusion-related copper prospect. Whereas the Delta mineral belt has been extensively mapped and explored, the detailed mapping does not continue into the 2015 Tok project area. In this area, only reconnaissance mapping has been conducted. The combination of a lack of detailed mapping, the industry interest in the adjacent areas, and the geophysical data findings prompted the Alaska Division of Geological & Geophysical Surveys (DGGS) mineral resources group to work in this area. DGGS geologists carried out a geologic reconnaissance mapping project in the Tanacross A-5, A-6, and parts of adjacent quadrangles from June 18 through 28, 2015. This dataset includes two samples with elevated gold, 1.3 and 14.5 ppm, accompanied with very high arsenic values (both over 10,000 ppm) and antimony values (352 and 97.4 ppm). The sample containing 14.5 ppm Au, 305 ppm Bi and 11.1 ppm Te (15ET026) was collected from sulfide pods in schist adjacent to a granitic intrusion near the Noah prospect, and the sample containing 1.3 ppm Au (15KS007) was collected from quartz veining in a fault zone. Major element chemistry has been obtained on the metamorphic rocks to distinguish between igneous and sedimentary protoliths of the rocks using criteria proposed by Dashevsky and others (2003) and on igneous rocks to characterize and differentiate Mesozoic and Cenozoic igneous deposits in the area. The analytical data tables associated with this report are being released in digital format as comma-delimited text (CSV) files.

The Tok project area is adjacent to the Delta mineral belt volcanogenic massive-sulfide (VMS) district, the Peak gold-silver-copper skarn, and structurally controlled gold and antimony mineralization in the Stibnite Creek and White Gold areas. The project area also includes the Noah prospect, an intrusion-related copper prospect. Whereas the Delta mineral belt has been extensively mapped and explored, the detailed mapping does not continue into the 2015 Tok project area. In this area, only reconnaissance mapping has been conducted. The combination of a lack of detailed mapping, the industry interest in the adjacent areas, and the geophysical data findings prompted the Alaska Division of Geological & Geophysical Surveys (DGGS) mineral resources group to work in this area. DGGS geologists carried out a geologic reconnaissance mapping project in the Tanacross A-5, A-6, and parts of adjacent quadrangles from June 18 through 28, 2015. This dataset includes two samples with elevated gold, 1.3 and 14.5 ppm, accompanied with very high arsenic values (both over 10,000 ppm) and antimony values (352 and 97.4 ppm). The sample containing 14.5 ppm Au, 305 ppm Bi and 11.1 ppm Te (15ET026) was collected from sulfide pods in schist adjacent to a granitic intrusion near the Noah prospect, and the sample containing 1.3 ppm Au (15KS007) was collected from quartz veining in a fault zone. Major element chemistry has been obtained on the metamorphic rocks to distinguish between igneous and sedimentary protoliths of the rocks using criteria proposed by Dashevsky and others (2003) and on igneous rocks to characterize and differentiate Mesozoic and Cenozoic igneous deposits in the area. The analytical data tables associated with this report are being released in digital format as comma-delimited text (CSV) files.

In 2016, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) and University of Alaska Fairbanks carried out a two-part geologic mapping and geochemical sampling project in the Tok River area of the Tanacross A-5 and A-6 quadrangles (June 12-26 and July 8-26). This report provides results of stream-sediment sampling for trace-element geochemistry. An initial suite of sediment samples was collected from streams draining known gold occurrences, including the Stibnite Creek and Noah prospects, and numerous prospects in the White Gold area. These samples were split in half and the two splits were sieved to -200 mesh and -80 mesh, respectively. The splits were then both analyzed to determine which size fraction was best for identifying gold anomalies in this part of the Alaska Range. In most samples, the -200 mesh fraction showed higher gold levels, and hence, all additional samples we collected were analyzed at -200 mesh. In some -80 mesh samples, gold and tungsten appear to show "nugget" effects not seen in the -200 mesh samples. The other trace elements are largely equivalent between the two mesh sizes. The second suite of samples was collected throughout the map area from streams draining color anomalies, from areas where DGGS mapping identified igneous rocks upstream, and from areas with suspected potential for base-metal or gold mineralization. Highlights of the analytical results include two samples draining the Noah prospect with greater than 1 part per million gold. The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files.

From June 12-21, 2017, the Alaska Division of Geological & Geophysical Surveys (DGGS) geologists carried out geologic mapping and geochemical sampling in the northeastern Tanacross D-1, and parts of the C-1, and D-2 quadrangles. The project area lies within the Yukon-Tanana Uplands, and encompasses the boundary between Fortymile and Lake George assemblages. It includes porphyry copper-molybdenum-gold deposits and prospects including: Taurus, Fishhook (also known as SW Pika), and Pika Canyon, and is adjacent to the Fortymile Mining District to the north. Highlights of this geochemical report include sampling and characterization of the Pika Canyon, Fishhook, and Taurus prospects. This dataset contains four samples with gold in excess of 0.1 parts per million (ppm) in several different locations, including two samples from Fishhook with 2.15 ppm and 0.697 ppm gold, respectively (17MBW119, 17MBW130), and a sample with 4,420 ppm silver and greater than 30 percent lead (17MLW002) collected nearby Pika Canyon. The DGGS Tanacross project area includes a section of Paleozoic and Mississippian- to Devonian-age, metasedimentary and metavolcanic rocks, as well as Jurassic(?) to Tertiary intrusive and volcanic rocks. Major- and trace-element geochemical analyses were obtained for metamorphic rocks to distinguish between igneous and sedimentary protoliths, and for igneous rocks to characterize and differentiate Mesozoic and Cenozoic rocks in the area. The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files. Additional details about the organization of information are noted in the accompanying metadata file. All files can be downloaded from the DGGS website (http://doi.org/10.14509/29778).

In conjunction with hosting field trips for the Association of American State Geologists 2016 annual meeting in Girdwood, Alaska, Alaska Division of Geological & Geophysical Surveys (DGGS) staff collected rock samples and obtained geochemical analysis from several readily accessible, but relatively unstudied outcrops. Samples were collected from Turnagain Arm (mile 104 Seward Highway), Whittier, Crow Pass, and Panorama Mountain (roughly mile 217 Parks Highway). Mineralized samples from veins and veinlets in granitic rocks from the Crow Pass and Whittier sites contain anomalous levels of gold ranging from 0.129 to 0.650 parts per million (ppm). Although none of the samples are from areas open to mineral entry, geochemical analyses of rocks from these localities may support interpretation of regional mineral-distribution trends. The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files. Additional details about the organization of information are noted in the accompanying metadata file. All files can be downloaded from the DGGS website (http://doi.org/10.14509/29725).

Late Triassic mafic to ultramafic intrusions in the Wrangellia terrane are host to magmatic sulfide nickel-copper-cobalt and platinum-group element (PGE) mineralization. DGGS's mineral-resources group carried out a geologic mapping project in the eastern Denali Highway region between Watana Creek and Paxson from July 29 through August 7, 2015. This project is part of a multi-year effort focusing on improving the publicly available geological and geochemical data and assessing the mineral potential of the less-explored extension of the western Wrangellia terrane; other data resulting from this project include geophysical surveys and several geochemical datasets. This program of geologic mapping and rock sampling was conducted as part of the State of Alaska's Strategic and Critical Minerals Assessment project, an initiative designed to evaluate Alaska's potential for rare-earth elements, PGEs, and other similarly supply-challenged resources. Highlights of this project include identification, sampling, and characterization of a broad section of Wrangellia stratigraphy, including Late Triassic ultramafic and mafic intrusions thought to be a part of the Ni-Cu-Co-PGE- and Cu-Ag-mineralized Wrangellia large igneous province. This dataset includes four samples with high copper values (1.6 to 4.62 percent) and elevated silver values (10.15 to 18.25 ppm) and two samples have elevated copper (1,400 and 4,610 ppm); those samples are scattered throughout the area. Two samples from the Caribou Dome area show elevated platinum (0.113 and 0.101 ppm) and palladium (0.141 and 0.193 ppm). The analytical data tables associated with this report are being released in digital format as comma-delimited text (CSV) files.

From June 19 through July 15, 2018, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic mapping and geochemical sampling project in the Northeast Tanacross map area, Tanacross D-1 and parts of C-1 and D-2 quadrangles. This area lies in the Yukon-Tanana terrane on the boundary between the Fortymile and Lake George Assemblages (Dusel-Bacon and others, 2006). It encompasses well-documented porphyry Cu-Mo-Au deposits including Taurus, Fishhook (otherwise known as SW Pika), and Pika Canyon, and is adjacent to the Fortymile Mining District. Highlights of this DGGS Northeast Tanacross geochemical report include identification, sampling, and characterization of the Taurus and Bluff prospects. This dataset has 20 samples with gold in excess of 0.1 ppm in several different locations, including a sample with 2.67 parts per million (ppm) Au (18MBW082) collected north of Taurus West, a sample with 1.2 ppm Au (18RN373) in drill core from the Bluff prospect, and 17 samples with 0.1 to 0.327 ppm Au (highest value reported for 18RN276) in drill cores from the Taurus prospect. Additionally, two samples with over 50 ppm Ag (18ET102 and 18ET307) were collected between the Pika Canyon and Fishhook Prospects. The DGGS map area includes a section of Mississippian to Devonian metasedimentary and metavolcanic rocks as well as Jurassic(?) to Tertiary intrusive and volcanic rocks. Major- and trace-element geochemistry was analyzed for metamorphic rocks to distinguish between igneous and sedimentary protoliths, and for igneous rocks to characterize and differentiate Mesozoic and Cenozoic magmatic events in the area. The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files. All files can be downloaded from the DGGS website (http://doi.org/10.14509/30113).

Geochemical data from samples collected in 2022 for the Mount Harper geologic mapping project, Big Delta, Mount Hayes, and Eagle quadrangles, Alaska, Raw Data File 2023-24, presents whole-rock and major- and trace-element geochemistry of rock samples collected to support geologic mapping and mineral exploration in the Mount Harper area of the Melozitna mining district. During the 2022 field season, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted 1:100,000-scale bedrock geologic mapping of ~3,100 mi2 (~8,000 km2) within the Big Delta, Mount Hayes, and Eagle quadrangles. This project aims to produce more detailed and modern geologic maps and supporting datasets to promote mineral resource exploration in eastern Interior Alaska. The project area includes known gold (Au) mineralization, recently explored in the Richardson mining district, including the SAM project and the nearby Democrat Lode and associated prospects, and in the Goodpaster mining district at the LMS and Healy intrusion-related gold prospects. The Mount Harper area hosts a cluster of molybdenum (Mo) and tungsten (W) prospects, including porphyry Mo and W skarn styles, both of which have had industry interest over the decades. Ultramafic rocks occur in the South Fork and Volkmar river drainages; these bodies have an as-yet poorly understood potential to host platinum group elements (PGE), chrome (Cr), cobalt (Co), and nickel (Ni) resources. The DGGS map area includes a section of pre-Mississippian to Permian metasedimentary and metaigneous rocks and Triassic to Paleogene intrusive and volcanic rocks. Major- and trace-element geochemistry for these rocks was analyzed to further our understanding of the resources in the area, including distinguishing between igneous and sedimentary protoliths for metamorphic rocks and characterizing and differentiating Mesozoic and Cenozoic magmatic events in the area. Highlights of this geochemical report include sampling of the Healy and LMS projects and multiple prospects on Mount Harper and elsewhere in the map area. Sample 22Z336, collected south of the Brink prospect, yielded 1.52 ppm Au and 500 ppm W. A few samples collected at the LMS prospect yielded elevated silver (Ag) concentrations (for example, sample 22Z409 yielded up to 12.95 ppm). Additionally, sample 22Z406 yielded 1.48 ppm Au, 7.65 ppm Ag, and 1,787 ppm arsenic (As). Samples collected at Larsen Ridge/Lucky 13 prospect near the top of Mount Harper yielded high Ag and W values. For example, 22Z271 (a massive quartz vein) yielded 18.87 ppm Ag and 1,100 ppm W, 22TJN157 (a skarn) yielded 5.75 ppm Ag, 2,348 ppm copper, 4,422 ppm manganese (Mn), and 600 ppm W, and 22Z270 (a granite) yielded 2,356 ppm Mo and 200 ppm W. The Richardson mining district has been previously sampled by DGGS. This data file is released as a Raw Data File with an open end-user license. The data are available from the DGGS website: http://doi.org/10.14509/31089.

Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys carried out a geological field survey, including mapping and sampling near Livengood in the Livengood B-3 and B-4 quadrangles, Alaska from June 10 to June 30, 2010. The fieldwork provides basic information critical to building an understanding of Alaska’s geology and is part of an integrated program of airborne geophysical surveys followed by geological mapping. During 2010, 130 rock samples were collected for geochemical trace-element analysis, and 20 rock samples were collected for whole rock (major- and minor-oxide) analysis. Petrogenetically important trace elements for additional rock samples will be analyzed and published with the final map and report for this area.