T4 Advances and Applications of Thermochronology to Tectonic, Magmatic, Basin, and Geomorphic Problems

Sunday, 22 September 2024
8:00 AM - 12:00 PM
212B

UNRAVELING THE THERMAL-HISTORY INFORMATION IN SEDIMENTARY ROCKS: FIRST RESULTS FROM ZIRCON U/Pb-(U-Th)/He-RAMAN TRIPLE-DATING

Paper number: T4-1
Program: Technical Sessions
Time: 8:00 AM – 8:20 AM

Authors

Abstract

Sedimentary rocks are excellent archives for geological processes because they record the cooling history of their source regions, the erosion and transport patterns over large spatial extents, and post-depositional thermal history. However, this multilayered information also complicates the process of extracting thermal histories from sedimentary rocks. To tackle this problem, it is necessary to develop new analytical strategies.

A promising candidate is laser-ablation-based zircon (U-Th)/He (LA-ZHe) dating. Several studies over the last two decades have explored the potential of applying this method to sedimentary rocks and individual detrital grains. It enables us to increase the number of dated grains compared to conventional ZHe dating, which requires time-consuming dissolution of whole grains. More importantly, the less destructive and spatially resolved laser ablation offers the prospect of combining high-n ZHe dating with other dating methods. Matching thermochronological with geochronological ages for each individual grain allows: (1) distinguishing magmatically cooled grains from grains that cooled during exhumation, (2) identifying source regions and tracing their cooling history, (3) comparing provenance information from different cooling populations.

We developed a new triple-dating workflow for zircon at the Geo-and Thermochronology Lab of the University of Calgary. It combines LA-ZHe and U-Pb dating with the radiation-damage-based zircon Raman thermochronometer. This approach constrains the crystallization age (U-Pb) and the timing of cooling through 330 ± 50 °C (Raman) and 180 ± 20 °C (ZHe) for each grain. We present the first results of applying triple-dating to Devonian and Cretaceous sandstone from the Mackenzie Plain, a foreland basin deposit of the Northern Canadian Cordillera.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-400886

© Copyright 2024 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.