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TitleGeochemical data for stream and groundwaters around the Casino Cu-Au-Mo porphyry deposit, Yukon (NTS 115 J/10 and 115 J/15)
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorKidder, J AORCID logo; McClenaghan, M BORCID logo; Leybourne, M I; McCurdy, M WORCID logo; Pelchat, P; Layton-Matthews, D; Beckett-Brown, C EORCID logo; Voinot, A
SourceGeological Survey of Canada, Open File 8823, 2022, 40 pages, Open Access logo Open Access
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatreadme
File formatpdf; rtf; xlsx (Microsoft® Excel®); xls (Microsoft® Excel®)
NTS115J/06; 115J/07; 115J/08; 115J/09; 115J/10; 115J/11; 115J/14; 115J/15; 115J/16
AreaPatton Hill; Patton Creek; Casino Creek; Taylor Creek; Canadian Creek; Lyman Creek; Rude Creek
Lat/Long WENS-139.3333 -138.1667 63.0000 62.3333
Subjectseconomic geology; geochemistry; surficial geology/geomorphology; Science and Technology; Nature and Environment; mineral deposits; porphyry deposits; copper; gold; molybdenum; placer deposits; mineral exploration; exploration methods; stream water geochemistry; groundwater geochemistry; trace element geochemistry; major element geochemistry; geochemical anomalies; stable isotope studies; oxygen isotopes; hydrogen isotopes; sulphur isotope ratios; strontium strontium ratios; total dissolved solids; sulphate; meteoric waters; pH patterns; conductivity; alkalinity; organic carbon; provenance; source rocks; bedrock geology; lithology; mineral occurrences; silver; lead; zinc; Casino Deposit; Yukon-Tanana Terrane; Intermontane Belt; Canadian Cordillera; Rhyolite Creek Complex; Prospector Mountain Suite; Casino Suite; Whitehorse Suite; Mount Nansen Group; Carmacks Group; Minto Suite; Stikine Suite; Sulphur Creek Suite; Klondike Schist; Simpson Range Suite; Finlayson Assemblage; Mount Baker Suite; Scottie Creek Formation; Snowcap Assemblage; Neoproterozoic; alluvial sediments; Phanerozoic; Cenozoic; Quaternary; Tertiary; Mesozoic; Cretaceous; Jurassic; Triassic; Paleozoic; Permian; Carboniferous; Mississippian; Devonian; Silurian; Ordovician; Precambrian; Proterozoic
Illustrationsgeoscientific sketch maps; location maps; plots; models; tables; ternary diagrams
ProgramTargeted Geoscience Initiative (TGI-6) Ore systems
Released2022 03 15
AbstractThis open file reports geochemical data for stream and groundwater samples collected around the Casino porphyry Cu-Au-Mo deposit, one of the largest and highest-grade deposits of its kind in Canada. The calc-alkaline porphyry is hosted in a Late Cretaceous quartz monzonite and associated breccias in the unglaciated region of west central Yukon. Water chemistry around the deposit was investigated because: (i) the deposit has not yet been disturbed by mining; (ii) the deposit was known to have metal-rich waters in local streams; and (iii) the deposit has atypically preserved ore zones. Stream water samples were collected at 22 sites and groundwater samples were collected from eight sites. Surface and groundwaters around the Casino deposit are anomalous with respect to Cd (up to 5.4 µg/L), Co (up to 64 µg/L), Cu (up to 1657 µg/L), Mo (up to 25 µg/L), As (up to 17 µg/L), Re (up to 0.7 µg/L), and Zn (up to 354 µg/L) concentrations. The stable isotopes of O and H of the groundwaters are essentially identical to the surface waters and plot close to the local and global meteoric water lines, indicating that the waters represent modern recharge, consistent with the generally low salinities of all the waters (total dissolved solids range from 98 to 1320 mg/L). Sulfur and Sr isotopes are consistent with proximal waters interacting with the Casino rocks and mineralization; a sulfide-rich bedrock sample from the deposit has delta-34S = -1.2 permille and proximal groundwaters are only slightly heavier (-0.3 to 3.1 permille). These geochemical and isotopic results indicate that surface water geochemistry is a suitable medium for mineral exploration for porphyry-style mineralization in the Yukon, and similar unglaciated regions in Canada. The atypical geochemical signature (Mo, Se, Re, As, Cu) of these types of deposits are typically reflected in the water chemistry and S isotopes provide a more local vectoring tool.
Summary(Plain Language Summary, not published)
Increasing the domestic supply of critical metals in Canada will require increased mineral exploration. However, discovery is notoriously difficult when the potential metal deposits are located deep in the bedrock or buried beneath surficial geological deposits, such as glacial sediments. Yet, in such scenarios, chemical interaction between waters and mineral deposits can result in the dispersion of dissolved metals, which can be an effective tool for mineral exploration. To demonstrate this, water samples in this study were collected from around the Casino Porphyry (Yukon) and underwent geochemical and isotopic analysis, with the results then interpreted to identify the extent of element dispersion in waters. The research results demonstrated that ground and surface water geochemistry is a suitable medium for mineral exploration for porphyry-style mineralization in the Yukon, and elsewhere in Canada.

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