Alaska Division of Geological & Geophysical Surveys (DGGS) personnel collected rock samples while mapping the bedrock geology along a 12-mile-wide swath following the Alaska Highway between Delta Junction and the eastern edge of the Mount Hayes quadrangle near Dot Lake, Alaska. This mapping is one component of the multi-year DGGS project studying the geology, geohazards and resources along the proposed gas pipeline corridor from Delta Junction to the Canadian border. In 2006, we collected 10 samples for whole rock (major- and minor-oxides, and petrogenetically important trace-elements) analysis. In 2007, we collected 111 samples for whole rock analysis and 36 rock samples for geochemical trace-element analysis. Analytical data from these rock samples are tabulated in this publication.

Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys carried out a geological field survey, including mapping and sampling, in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2, and the Healy D-1 and D-2 quadrangles, Alaska, from June 16 through July 18, 2008. 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. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. To represent a typical lithology, igneous or possible meta-igneous samples were collected and analyzed for major- and minor-oxide and petrogenetically important trace elements as a supplement to previously published geochemical data. The analyses were used to determine composition of the samples as well as potential original tectonic setting. Radiometric age analyses from some of these rocks have been published. Interpretation and synthesis of this data has been presented in professional and trade meetings. The analytical tables associated with this data release are available in digital format as comma-separated value (CSV) files.

Cook Inlet has been recognized as the second-largest petroleum province in Alaska, second only to the North Slope. The south-central Tyonek Quadrangle is an area of significant geologic interest because it is the only location in Cook Inlet where the entire producing stratigraphy of the basin is exposed on the surface. Additionally, this area encompasses the structural boundary between the forearc basin and its sediment source rocks. To better understand the petroleum system and the geologic relationships between the exhumed arc intrusive rocks and adjacent Cenozoic stratigraphy of the Cook Inlet forearc basin, during the summer of 2010 the Alaska Division of Geological & Geophysical Surveys conducted a federally-funded geologic field mapping project. As a part of this project DGGS collected 44 rock samples for geochemical analyses from Late Cretaceous and Paleogene intrusive and volcanic lithologies that compose part of the Alaska-Aleutian Range batholith and arc. Major-oxide, minor-oxide, and trace-element geochemical data presented here provide new information about the genesis and potential mineralization of igneous rocks in the western Neacola and southern Tordrillo mountains. The analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files.

Major-oxide and trace-element geochemical data from rocks collected near the Dalton Highway, Yukon River crossing, Alaska, Raw Data File 2025-29, provides major-oxide and trace-element geochemical data from rocks collected near the Dalton Highway, Yukon River Crossing, Alaska. Geologists from the Alaska Division of Geological and Geophysical Surveys (DGGS) conducted fieldwork between June and July 2016 in the Livengood D-6, C-6, and northern B-6 quadrangles, as part of the Yukon River Crossing Capital Improvement Project. The study area spans about 567 mi2 (1,458 km2) and includes a geologically complex and vulnerable segment of the Trans Alaska Pipeline and Dalton Highway. The project seeks to improve understanding of the local geology and evaluate the potential for slope instability near the Yukon River highway crossing, where a 2012 landslide occurred west of the bridge's south abutment. The team collected igneous and metamorphic rock samples and conducted whole-rock geochemical analyses, including major oxide and trace element concentrations, to define map units and assess lithologic variability relevant to slope stability and infrastructure risk. These data are provided as a Raw Data File under an open end-user license and are available on the DGGS website: http://doi.org/10.14509/31737.

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.

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).

During the 2018 field season, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted geologic mapping and sampling of part of the Richardson mining district southeast of Fairbanks, including parts of the Big Delta B-5 and B-6 quadrangles. The project area has produced approximately 122,000 ounces of gold (Singh and others, 2017), mostly from placer mines, and it includes the Richardson, Tower, and Hilltop lode gold exploration properties. Rock outcrop accounts for much less than one percent of the study area, consequently, many of the rock samples were collected from up to 1-meter-deep pits dug with shovels into rocky colluvial deposits below the surficial loess. Highlights of the geochemical results include 43.3 and 9.77 parts per million (ppm) gold sampled from arsenopyrite-bearing quartz veins at the Hilltop prospect. At the Democrat prospect, formerly the site of small-scale mining, a sample of sulfide-rich material returned 3,790 ppm silver and 4.72 ppm gold. Other samples from the Democrat prospect assayed 6.81 and 5.01 ppm gold. 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/10.14509/30119).

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 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).