212-7 Detrital Zircon U-Pb Geochronology of the Selwyn Basin, Canada: Implications for Stratigraphic Correlation and Provenance of the Late Devonian Earn Group

Session: Reconstructing Earth Surface Processes in Orogenic Systems

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The Paleozoic Selwyn Basin spans the Yukon, Northwest Territories, and British Columbia, Canada and hosts sedimentary-hosted massive sulfide (SHMS) Zn-Pb deposits distributed throughout Cambrian–Early Carboniferous stratigraphic units. Tecto-sedimentary evolution within the Selwyn Basin created ideal conditions for SHMS formation and significant critical metal accumulation at multiple times and locations. The Earn Group represents a key mineralized stratigraphic unit within this sequence, preserving renewed coarse clastic deposition associated with the onset of eastward subduction and the transition from a passive margin to an actively rifting back-arc setting during the Late Devonian. However, the spatiotemporal distribution, provenance, and subsidence records of this tectonic shift across western Canada remain poorly constrained, hindering our understanding of the relationship between tectonic evolution and SHMS mineralization processes. Preliminary detrital zircon U-Pb ages from the Howards Pass and Macmillan Pass regions provide depositional age constraints for the Earn Group along its eastern extent in the Yukon, forming a basis for stratigraphic correlation across the basin and provenance characterization. These results help define spatiotemporal patterns of sedimentation and paleodrainage reorganization and their potential controls on the timing and locus of SHMS mineralization.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9630

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