The mineral-resources group from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic mapping project in the Talkeetna Mountains C-4, C-3, and B-4 quadrangles from July 23 through August 3, 2014. This project is a part of a multi-year project 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. This program of geologic mapping and rock sampling was conducted as part of the U.S. Geological Survey National Cooperative Geologic Mapping Program and the state of Alaska's Strategic Minerals Assessment project, an initiative designed to evaluate Alaska's potential for rare-earth elements, PGEs (platinum group elements), and other similarly supply-challenged resources. Highlights of this project include identification, sampling, and characterization of a broad section of the Wrangellia stratigraphy, including Late Triassic rocks of the Ni-Cu-Co-PGE- and Cu-Ag-mineralized Wrangellia large igneous province as well as modern geochemical characterizations of skarn, vein, and basalt-hosted Cu mineralization. This data set includes four samples with elevated gold, ranging from 0.5 to 0.875 ppm, with one of these samples also containing elevated Cu (1.18 percent). Twelve samples have elevated copper, ranging from 1000 to 7900 parts per million, and two samples contain a significant copper spike (13 and 19.65 percent) and elevated silver (42 and 48 parts per million). The analytical data tables associated with this report are being released in digital format as comma-delimited text (CSV) files.

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 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 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.

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.

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.

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.

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.

The State of Alaska's Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska's statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. For the geochemical part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly identify areas in Alaska with SCM potential. For this report, DGGS funded reanalysis of 1,682 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from an area covering the western half of the Wrangellia Terrane in the Anchorage, Gulkana, Healy, Mt. Hayes, Nabesna, and Talkeetna Mountains quadrangles of south-central Alaska. USGS was responsible for sample retrieval from the Denver warehouse through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract lab. The new geochemical data are published in this report as a coauthored DGGS report, and will be incorporated into the statewide geochemical databases of both agencies.