A new research project was begun in 2002, aimed at better understanding the nature and origin of copper-gold mineralization and its main host rocks at the Minto and Williams Creek (Carmacks Copper) deposits in west-central Yukon. This will also help to further constrain exploration models both on a property and a regional scale. Field work in 2002 confirmed that the main host rocks for both deposits are variably deformed plutonic rocks (diorite and quartz diorite at Williams Creek and mainly granodiorite at Minto). Mineralization formed prior to the ductile deformation that has affected these units. Mineralized granodioritic gneiss from Minto and apparently post-mineralization quartz diorite at Williams Creek yield U-Pb ages of ~194 Ma and ~191 Ma, respectively; thus the mineralization appears to have formed at essentially the same time as the host intrusions. Reconnaissance Pb- and S-isotope analyses of sulphide minerals from both deposits also indicate a likely magmatic source for the mineralization.

Auriferous sheeted quartz veins and silicified shear zones occur along the margins and within adjacent hornfels zones of mid-Cretaceous Tombstone intrusions near the head of Clear Creek in the central Yukon. The lodes are the source for more than 120,000 ounces of downstream placer gold production. These lodes contain variable amounts pyrrhotite, pyrite, and arsenopyrite, with less abundant scheelite - alkali-feldspar, muscovite, biotite and tourmaline are common gangue phases. Grab samples of mineralization often contain gold grades in excess of 1 ounce per ton. Gold-to-silver ratios vary most commonly from 1:1 to 5:1. Gold-rich quartz veins cut all stocks, adjacent hornfels and associated lamprophyre dykes commonly contain greater than 1% arsenic. Bismuth, and less consistently tungsten and stibnite, characterize many of the most highly mineralized veins within and surrounding the stocks. Quartz veins along the intrusive-metasedimentary rock contact around the Pukelman stock are also enriched in lead and silver. R-mode factor analysis of multi-element geochemical data for 111 gold- and sulphide-bearing rock samples indicates that there are two geochemically distinct metal suites in the Clear Creek occurrences. The first is characterized by As-Au-Bi ± Sb, Te ore-related mineral association, which is typical of many intrusion-related deposits in the Tombstone gold belt. Less consistently, anomalous concentrations of Ag, Co, Cu, Fe, and Mo occur within these auriferous rocks. The second metal factor is defined by Ag-Bi-Pb ± As, Au and Te. It characterizes metalliferous vein samples that have uncommonly low Au: Ag ratios and may represent a second hydrothermal episode. Tungsten shows little consistent correlation with the metalliferous veins in either element suite.

Porphyry copper deposits are the world's primary source of copper and can also host a variety of secondary commodities identified as critical by the U.S. Geological Survey (U.S. Geological Survey, 2022). These deposits occur primarily along convergent plate margins, and their metal association and geochemical characteristics are reflective of whether the deposit formed in continental/island arc, back-arc, or syn- to post-collisional environments (e.g., Hofstra and others, 2021). Based on this association, understanding the location, age, and endowment of global porphyry deposits can be leveraged to identify prospective regions for discovery of new porphyry deposits along these ancient margins. This data release is a compilation and update from previously published global and regional datasets of porphyry copper deposits and prospects. The data sheet includes deposit names and their location, age (if known, and including analytical method), deposit classification based on Hofstra and others (2021), interpreted tectonic origin, and grade-tonnage compiled from public databases where available. The final spreadsheet represents the most up-to-date published information of global porphyry copper deposits and prospects as of Spring 2024. References Hofstra, A., Lisitsin, V., Corriveau, L., Paradis, S., Peter, J., Lauzière, K., Lawley, C., Gadd, M., Pilote, J., Honsberger, I., Bastrakov, E., Champion, D., Czarnota, K., Doublier, M., Huston, D., Raymond, O., VanDerWielen, S., Emsbo, P., Granitto, M., and Kreiner, D., 2021, Deposit classification scheme for the Critical Minerals Mapping Initiative Global Geochemical Database: U.S. Geological Survey Open-File Report 2021–1049, 60 p., https://doi.org/ 10.3133/ ofr20211049. U.S. Geological Survey, 2022, 2022 Final List of Critical Minerals: Federal Register Document 2022-04027, p. 10381-10382. (available at https://www.federalregister.gov/documents/2022/02/24/2022-04027/2022-final-list-of-critical-minerals).

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This report and digital data release presents 90 new geochemical analyses on historic U.S. Bureau of Mines (USBM) samples, including 56 rock, 16 sediment, 5 soil, and 12 heavy mineral concentrate (pan concentrate) samples, as well as 1 sample of indeterminate type. Some of these samples were originally collected by the USBM as part of their mineral investigations in the Porcupine River drainage, northeastern Alaska, and a portion of the samples were collected as part of the National Uranium Resource Evaluation. Historic USBM sample materials were retrieved by DGGS from the DGGS Geologic Materials Center (GMC), where the USBM samples were transferred as part of the federally funded Minerals Data and Information Rescue in Alaska (MDIRA) program in the late 1990s and early 2000s. The text and analytical data and tables associated with this report are being released in digital format as PDF files and .csv files. We provide analytical data, detection limits and, when available, the method documentation provided to us by the lab. We also provide the sample location in geographic coordinates, the sample material cited by the originating literature, a reference to the originating report, and the type of sample material that was obtained from the archive and sent to the lab.

The Andes Mountains of South America host significant porphyry copper deposits. The region is the major global source of copper and an area of active mining, exploration, and development. The Andes region was included in USGS global compilations of porphyry deposits published by Singer and others in 2005 and 2008. Since that time, many new discoveries and new resource data have become available. This compilation includes new and updated location, references, and grade and tonnage data for porphyry copper deposits in the Andes along with grade and tonnage data from the previous compilations. The data release includes a data table, references, and shapefiles of porphyry copper locations and political boundaries.

This report and digital data release presents 40 new geochemical analyses on historic U.S. Bureau of Mines (USBM) samples, including 33 rock and 7 heavy mineral concentrate (pan concentrate) samples. These samples were originally collected by the USBM as part of their critical and strategic minerals project, which investigated the rare-earth-element and uranium mineral potential of the Zane Hills area, northwestern Alaska. Historic USBM sample materials were retrieved by DGGS from the DGGS Geologic Materials Center (GMC), where the USBM samples were transferred as part of the federally funded Minerals Data and Information Rescue in Alaska (MDIRA) program in the late 1990s and early 2000s. The text and analytical data and tables associated with this report are being released in digital format as PDF files and .csv files. We provide analytical data, detection limits and, when available, the method documentation provided to us by the lab. We also provide the sample location in geographic coordinates, the sample material cited by the originating literature, a reference to the originating report, and the type of sample material that was obtained from the archive and sent to the lab.

The dataset comprises analyses of core and surface samples collected in and around the Red Mountain porphyry Cu-Mo deposit, Santa Cruz County, Arizona. The dataset includes: analyses for 13 minerals in 245 core samples (Appendix 1); analyses for 44 elements in 818 core samples (Appendix 2); analyses for 54 elements in 122 rock samples (Appendix 3); analyses for 55 elements in 119 soil samples (Appendix 4); and analyses for percent ash and 66 elements in 57 mesquite ash (Appendix 5), 68 oak ash (Appendix 6), and 68 juniper ash (Appendix 7) samples, respectively. The samples were collected and analyzed between 1980 and 2000.

The dataset comprises analyses of core and surface samples collected in and around the Red Mountain porphyry Cu-Mo deposit, Santa Cruz County, Arizona. The dataset includes: analyses for 13 minerals in 245 core samples (Appendix 1); analyses for 44 elements in 818 core samples (Appendix 2); analyses for 54 elements in 122 rock samples (Appendix 3); analyses for 55 elements in 119 soil samples (Appendix 4); and analyses for percent ash and 66 elements in 57 mesquite ash (Appendix 5), 68 oak ash (Appendix 6), and 68 juniper ash (Appendix 7) samples, respectively. The samples were collected and analyzed between 1980 and 2000.