20 The Boring Billion was not so Boring! Mesoproterozoic Tectonics, Sedimentation, and Geochronology of Northwest Laurentia I

Thursday, 16 May 2024
8:00 AM - 12:00 PM
Cedar Ballroom

STRATIGRAPHY OF MESOPROTEROZOIC UNITS PR1 AND PR2 IN THE COAL CREEK INLIER, YUKON, CANADA: POSSIBLE PINGUICULA GROUP CORRELATIVES

Paper number: 20-7
Program: Theme Sessions
Time: 9:45 AM – 10:05 AM

Authors

Abstract

Proterozoic strata in central Yukon are exposed in the Coal Creek, Hart River, and Wernecke inliers. The Paleoproterozoic and Neoproterozoic strata are well correlated across the inliers, but correlation of the Mesoproterozoic units remains ambiguous. Lithostratigraphic considerations support a correlation between the Mesoproterozoic Pinguicula Group in the Hart River and Wernecke inliers and PR1 and PR2 in the Coal Creek inlier. However, detrital zircon analyses of PR1 yielded a near unimodal peak at 1.5 Ga that is absent from analyses of the Pinguicula Group and challenged this correlation. Here we present stratigraphic logs of units PR1 and PR2 in the Coal Creek inlier. PR1 is dominantly siltstone and sandstone deposited in a deep-water environment and PR2 is mostly dolostone deposited in a shallower environment above storm weather wave base. Together, PR1 and PR2 are composed of a single, thick, shoaling-upward sequence similar to the Pinguicula Group. Based on similarities in the stratigraphy and contact relationships with underlying and overlying units, we suggest that PR1 and PR2 are correlative with the Pinguicula Group. Future work to test this correlation will involve high-n detrital zircon geochronology and measuring additional sections of PR1 and PR2 in the Coal Creek inlier and the Pinguicula Group in the Wernecke inlier. Resolving how PR1 and PR2 correlate with Proterozoic strata exposed in other inliers provides insight into basin development along northwest Laurentia during the Meso–Neoproterozoic.

Geological Society of America Abstracts with Programs. Vol. 56, No. 4

doi: 10.1130/abs/2024CD-399421

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