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TitleU-Pb vein calcite dating reveals the age of Carlin-type gold zones of central Yukon, and a contemporaneity with a regional intrusion-related metallogenic event
 
AuthorPinet, N; Davis, W JORCID logo; Petts, D CORCID logo; Sack, P; Mercier-Langevin, P; Lavoie, DORCID logo; Jackson, S JORCID logo
SourceEconomic Geology vol. 117, no. 4, 2022 p. 905-922, https://doi.org/10.5382/econgeo.4898
Image
Year2022
Alt SeriesNatural Resources Canada, Contribution Series 20210253
PublisherSociety of Economic Geologists
Documentserial
Lang.English
Mediapaper; digital; on-line
File formatpdf
ProvinceYukon
NTS95C; 95D; 105; 115; 116; 105K/01; 105K/02; 105K/03; 105K/04
Lat/Long WENS-134.0000 -132.0000 64.2500 64.0000
Subjectsgeochronology; calcite; mass spectrometer analysis; lead uranium ratios; hydrothermal deposits; Carlin
Illustrationslocation maps; tables; schematic representations; photographs; Concordia diagrams; plots; element distribution diagrams; histograms
ProgramTargeted Geoscience Initiative (TGI-5) Gold ore systems
Released2022 02 01
AbstractLaser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb dating of hydrothermal calcite associated with the waning stage of mineralization is used to constrain the age of Neoproterozoic-hosted Carlin-type gold deposits in central Yukon, Canada. Samples exhibiting minor textural complexity show low dispersion of individual spot analyses and define Tera-Wasserburg lower intercept ages between 75.1 ± 2.5 and 71.2 ± 4.3 Ma. Samples with U-rich microfractures and/or a second generation of calcite associated with vein reopening record the primary stage of calcite growth related to hydrothermal activity at ca. 74 Ma and a younger ca. 48 Ma event related to fluid-assisted U mobility. The minimum age for mineralization at ca. 74 Ma overlaps with a maximum age based on a zircon U-Pb date of 74.1 ± 1.0 Ma for a gabbro dike that is locally altered and mineralized. These time constraints indicate that mineralization is ca. 74 Ma and penecontemporaneous with dike emplacement. Furthermore, mineralization is contemporaneous with a regional gold-bearing, intrusion-related, metallogenic event in eastern Alaska and central Yukon. This temporal link between Carlintype mineralization and other mineralization types bears similarities with world-class sedimentary rock-hosted gold deposits of Nevada. This study demonstrates the potential of using LA-ICP-MS U-Pb dating on calcite to constrain the age of mineral deposits lacking synmineralization minerals amenable to classic dating techniques.
Summary(Plain Language Summary, not published)
A relatively new geochronology method (U-Pb dating of calcite) is used for the first time at the GSC to date hydrothermalism associated with gold mineralization. This study: 1) constrains the age of Carlin type mineralization in Yukon at ca 74 Ma, which demonstrates a contemporaneity with a regional gold event documented hundreds of kilometers to the west; 2) shows the potential of the method that will undoubtedly generate new data and ideas in economic geology.
GEOSCAN ID328883

 
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