The term "Klondike Schist" describes metamorphosed igneous and sedimentary rocks first described from the Klondike area and later from south central Yukon. This paper describes the geology and chemistry of selected iron and base metal occurrences in Klondike Schist and proposes a model to assist further exploration for and evaluation of this type of mineralization. Four mineralized occurrences were examined in 1978, three on the northeast side of Tintina Fault in the Pelly Mountains - Fire Lake, North Lakes and Wolverine Lake and one southwest of the Tintina Fault, the Boundary prospect west of Dawson.

The data release includes GIS data that map potential for tungsten skarn mineralization in permissive tracts in the Yukon-Tanana Uplands, Eastern Alaska, along with tables listing keywords and procedures used to produce the permissive tracts and score them for mineral potential.The GIS data are encapsulated in a file geodatabase called "AK_Wskarn_tract.gdb" and are also available in the shapefile and KMZ formats. The geodatabase contains three datasets. The polygon feature class "primary_attributes" contains the scored tungsten skarn permissive tract subdivided by National Hydrography Dataset HUC12 drainages. A related table, "qualitative_assessment" contains detailed scoring information for each feature. The point feature class "mineral_sites_ranked" contains W (tungsten) bearing mineral sites pulled from the Alaska Resource Data File with additional fields added for this study. The GIS data folder also includes the Python script used to score potential.

This data release supports the paper titled, “Tungsten skarn potential of the Yukon-Tanana Uplands, Eastern Alaska, USA-A mineral resource assessment”, published via open-access license in the Journal of Geochemical Exploration and available at: https://doi.org/10.1016/j.gexplo.2020.106700. The data release includes GIS data that map potential for tungsten skarn mineralization in permissive tracts in the Yukon-Tanana Uplands, Eastern Alaska, along with tables listing keywords and procedures used to produce the permissive tracts and score them for mineral potential. Supplementary Data part A lists keywords used to extract permissive rock types from the Geologic Map of Alaska (Wilson et al., 2015) to generate the permissive tract for tungsten skarn. Supplementary Data part B describes the tract polishing procedures. Supplementary Data part C lists the parameters for scoring tungsten skarn mineralization potential within the permissive tract features. The GIS data are encapsulated in a file geodatabase called AK_Wskarn_tract.gdb and are also available in the shapefile and KML formats. The geodatabase contains three datasets. The polygon feature class “primary_attributes” contains the scored tungsten skarn permissive tract subdivided by National Hydrography Dataset HUC12 drainages. A related table, “qualitative_assessment” contains detailed scoring information for each feature. The point feature class “mineral_sites_ranked” contains W-bearing mineral sites pulled from the Alaska Resource Data File with additional fields added for this study. The GIS data folder also includes the Python script used to score potential. The datasets and methods are described in detail in the accompanying paper.

A copy of this thesis is available at the EMR library – QE446.Y8 S83.

This report focuses on a selection of some of the most valuable gemstones in the global gem trade; ruby, sapphire, emerald, chrysoberyl, tsavorite garnet, tanzanite, and the gem minerals (topaz, aquamarine, tourmaline) found in pegmatites or rhyolites. Exploration criteria for other gemstones such as opal, nephrite jade, jadeite jade, zircon, lapis lazuli, and rhodonite are beyond the scope of this report. For each gem mineral covered in this report, background information is introduced and the physical and chemical characteristics are presented. The geology and genesis of each gem deposit type is summarized and exploration guidelines listed. Because pegmatites are so closely associated with several gemstones including aquamarine, tourmaline and topaz, there is a chapter devoted to pegmatites and their gem minerals. Topaz rhyolite is a distinctive deposit type which is discussed in Chapter Eight. Application of the exploration criteria to Yukon geology is given in Chapter Nine. A reference list is provided for those readers who want to pursue further details.

Kalzas, in central Yukon, is a porphyry-style stockwork and sheeted-vein wolframite deposit. Alteration includes a potassic core, a quartz-tourmaline-sericite zone and an outer quartz-sericite-pyrite zone, the latter in excess of 2 km in diameter. Wolframite is confined to the inner two zones, in an oval area 1500 m by 800 m. The wolframite is disseminated within the quartz-tourmaline stockwork and also occurs as coarse crystals in sheeted veins. Mineralization occurs within Neoproterozoic to Early Cambrian Hyland Group quartzites and phyllites, which are likely intruded at depth by a pluton, possibly of the Cretaceous Tombstone Suite. From 1981 to 1984, Union Carbide carried out mapping, soil and rock geochemistry, an airborne magnetometer survey, road building, trenching and drilling of two diamond drill holes. Results from Copper Ridge's 2001 sample program range from 0.3% WO3 to 0.5% WO3 over widths up to 70 m. They demonstrate the potential to define a signifi cant resource of surface-mineable tungsten mineralization at a grade of 0.4% WO3 or better. Drilling is required to confirm grade continuity at depth and along strike.

The purpose of the project is to use the lithostratigraphic data in the Yukon bedrock geology geodatabase to rank geologic polygons in terms of their capability to host mineral deposits. Twelve specific mineral deposit models are considered; lithostratigraphic metallotect maps have been created for each deposit type. These maps and the associated table of metallotect rankings are envisioned as layers of information for mineral potential studies and mineral exploration.

A mineralogical study was conducted by the Applied Mineralogy Group on a niobium-bearing rare earth ore from the Lancer deposit in Yukon as a cost recovery project for Mr. Dodge, President Dodgex Ltd. The study was conducted in two parts. One part is to identify the minerals and to determine the compositions and modes of occurrence of rare earth minerals, and the second part is to determine the relative quantities of the rare earth minerals and to determine their liberation characteristics.

This report is an updated version of an Open File report (Walton, 1996) describing the geology and geochemistry of gemstone deposits and applicable exploration criteria.The 1996 report, and this update, are both aimed at exploration geologists and prospectors who are unfamiliar with the geology of gemstone deposits and how to explore for them. Its objective is to provide information on gemstone deposit geology and provide general guidelines for the identification of, and exploration for, gemstone occurrences. The report focuses on a selection of some of the most valuable gemstones in the global gem trade: ruby, sapphire, emerald, chrysoberyl, tsavorite garnet, tanzanite and the gem minerals (topaz, aquamarine, tourmaline) found in permatites or rhyolites. Exploration criteria for other gemstones such as opal, nephrite jade, jadeite jade, zircon, lapis lazuli and rhondonite are beyond the scope of this report. For each gem mineral covered in this report, background information is introduced and the physical and chemical characteristics of the gem are presented. The geology and genesis of each gem deposit type is summarized and exploration guidelines are listed. One of the difficulties in developing exploration guidelines is that many of the world's gem deposits are unique. It is difficult to determine the range of variations and physico-chemical conditions under which a particular type of gemstone deposit may form, if there is only one deposit to study.

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