T121 Sedimentary Geology Division/SEPM Student Research Competition: Dynamics of Stratigraphy and Sedimentation (Posters)

Monday, 5 November 2018
9:00 AM - 6:30 PM
Halls J-K

DETRITAL ZIRCON PROVINCE OF THE JURASSIC SUNDANCE FORMATION LOCATED IN BUFFALO, WYOMING

Paper number: T121-38
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The Jurassic Sundance formation of Wyoming was deposited during the transition from cratonic to synorogenic sedimentation in the Sevier-Laramide foreland. The Sundance in the western Powder river basin consists of an oolitic limestone and green glauconitic sandstone at the base, green shales in the middle, and a yellow quartz arenite with coquina “oyster” beds at the top. U-Pb analyses of detrital zircons using LA-ICP-MS were conducted on two samples collected in the Bud Love wildlife habitat management area, 10 km northwest of Buffalo, WY. The two samples were taken from the upper and lower sandstone members of the Sundance formation (n=288 total zircons). The samples show a distinct difference in detrital zircon age spectra. The lower sandstone age spectrum ranges from 260-3172 ma with 22.6% of the ages being Paleozoic, 71.4% being Proterozoic, and 6% being Archean. this lower stratum has detrital zircon age peaks at 343, 432, 686, 1039, 1431, 1662, 1748, 1941, 2433, and 3179 Ma. In comparison to the upper strata, with ages ranging from 157-2949 Ma and age peaks at 170, 243, 440, 545, 1082, 1467, 1681, and 1985 Ma. The maximum deposition age for the upper member is 157 Ma. Mesozoic aged grains make up 15.6% of the zircons, 14.7% were Paleozoic, 65.7% were Proterozoic, and 4% were Archean in age. The appearance of Mesozoic zircons in the upper sandstone marks the first significant appearance of westerly sourced zircons, and perhaps reflects the earliest uplift of the Sevier fold and thrust belt. The lower sandstone shows an easterly Appalachian-Ouachita provenance, which persisted in the region since the beginning of the Carboniferous. Mesozoic aged grains appear in the upper stratum which are interpreted to being derived from arc terranes being exposed due to Cordilleran orogeny to the west.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-321466

© Copyright 2018 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.