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.

Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys carried out a geological field survey, including mapping and sampling northeast of Fairbanks in the Circle A-4, A-5, B-4, and B-5 quadrangles, Alaska from May 31 to June 28, 2007. The fieldwork provides basic information critical to building an understanding of Alaska geology and is part of an integrated program of airborne geophysical surveys followed by geological mapping. During 2007, 128 rock samples were collected for geochemical trace-element analysis, and 44 rock samples were collected for whole rock (major- and minor-oxide) analysis. Petrogenetically important trace-elements will be analyzed in a subsequent study to be published with the final map and report for this area. In addition, 67 stream sediment samples were collected for geochemical trace-element analysis. The stream sediment geochemical study was conducted over the proposed Mount Ryan Remote Recreational Cabin Staking Area as considered by Alaska's Division of Mining, Land & Water in 2007.

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.

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, A-2, Healy D-1 and D-2 quadrangles, Alaska from June 16 to July 18, 2008. The fieldwork provides basic information critical to building an understanding of Alaska geology and is part of an integrated program of airborne geophysical surveys followed by geological mapping. During 2008, 242 rock samples were collected for geochemical trace-element analysis, 106 rock samples were collected for whole rock (major- and minor-oxide and petrogenetically important trace element) analyses, and 7 samples were collected for analysis of non-carbonate carbon content.

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).

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.

Geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) and the University of Alaska Fairbanks (UAF) carried out geologic field surveys, including bedrock mapping and sampling, in the Alaska Highway Corridor from 2006 through 2010. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of a broader, integrated program that includes airborne geophysical surveys, bedrock and surficial mapping, a mineral-resource assessment, a geologic-hazards assessment, and other geological studies. This publication contains descriptive, location, and analytical information for samples collected in the Mount Hayes, Tanacross, and Nabesna quadrangles, Alaska, in the summers of 2006, 2008, 2009, and 2010. Additional analytical data for samples collected in the Mount Hayes Quadrangle in the summers of 2006 and 2007 were published in a separate report. During the field seasons covered by this report, rock samples were collected for geochemical trace-element and whole-rock (major- and minor-oxide and petrogenetically important trace-element) analyses. Rock sample location coordinates are presented in decimal degree latitude and longitude based on the North American Datum of 1927 (NAD 27) for Alaska. Brief sample descriptions are based principally on field observations with some thin-section details added.

Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys carried out a geologic field survey, including mapping and sampling in the Moran area in the Tanana A-6 and B-6 quadrangles, and the Melozitna A-1, A-2, B-1, and B-2 quadrangles, Alaska, from June 17 to August 15, 2011. 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 geologic mapping. During 2011, 212 rock samples were collected for geochemical trace-element analysis (tables 1–3), 58 rock samples were collected for whole-rock (major- and minor-oxide and petrogenetically important trace elements) analyses, two samples were collected for analysis of non-carbonate carbon content, 439 polished rock slabs were analyzed for whole rock and petrogenetically important trace elements, and 26 samples were analyzed for rare earth elements.

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 geologic field survey, including mapping and sampling in the Moran area in the Tanana A-6 and B-6 quadrangles, and the Melozitna A-1, A2, B-1, and B-2 quadrangles, Alaska from June 17 to August 15, 2011. The fieldwork provides basic information critical to building an understanding of Alaska geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. During 2011, 212 rock samples were collected for geochemical trace-element analysis, 58 rock samples were collected for whole-rock (major- and minor-oxide and petrogenetically important trace elements tables) analyses, and two samples were collected for analysis of non-carbonate carbon content. Additionally, 352 polished rock slabs were analyzed for whole-rock and petrogenetically important trace elements.