T352 Improvements and Challenges in Geochronology: Organizing the Past while Planning for the Future (Posters)

Wednesday, 25 October 2017
9:00 AM - 6:30 PM
Halls 4EF

MOVING LEGACY DATA FORWARD: HARMONIZING 40AR/39AR ERUPTION AGES FOR THE THREE YELLOWSTONE SUPER-ERUPTIONS

Paper number: T352-3
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Over the last several decades, the use of 40Ar/39Ar radioisotopic dating has become the gold standard for Quaternary volcanic geochronology. Developments in instrumentation, along with intercalibration with other dating techniques, have led to advancements in improving accuracy while simultaneously reducing precision. However, these advancements have come with their disadvantages. As different laboratories adopt their own preferred values for monitor mineral ages and decay constants, and publish new ages for eruptions, it becomes necessary to recalculate all ages to a common monitor in order to accurately compare results across different laboratories and more accurately evaluate the mean age of various eruptions. In this work, we compiled and recalculated all published analyses for the Lava Creek, Mesa Falls, and Huckleberry Ridge Tuffs relative to the Fish Canyon sanidine monitor of 28.201 Ma (Kuiper et al., 2008) with the decay constants of Min et al. (2000). We applied a rigorous set of criteria to identify outliers within the compiled dataset to compute new eruption ages, and analyzed how these criteria affect the calculated age. New calculated eruption ages were compared to individual authors’ preferred eruption ages and the distribution of the ages was analyzed over the last four decades. Our analysis shows the discrepancies between preferred ages and those determined using strict guidelines on data inclusion, as well as discrepancies between laboratories. Our compiled dataset is provided to the geochronology community as a downloadable file via the Geochemical Resource Library.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-300077

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