High-Precision U-Pb Zircon Age Constraints on the Duration of Rapid Biogeochemical Events During the Ludlow Epoch (Silurian Period)

Authors

Bradley D. Cramer, University of Iowa
Mark D. Schmitz, Boise State UniversityFollow
Warren D. Huff, University of Cincinnati
Stig M. Bergström, Ohio State University

Document Type

Article

Publication Date

3-2015

Abstract

Precise determinations of the rates and durations of Palaeozoic biogeochemical events are largely unavailable. Here, we present two new high-precision U–Pb (zircon) dates from volcanic ash deposits from the Ludlow Series (Silurian System) of Podolia, Ukraine, that yielded weighted mean ²⁰⁶Pb/²³⁸U dates of 424.08 ± 0.20 (0.29) [0.53] Ma and 422.91 ± 0.07 (0.21) [0.49] Ma (analytical, tracer and total uncertainties). These new dates bracket the largest post-Cambrian global carbon cycle perturbation (Lau Excursion) and constrain the ‘Ludlow Rise’ in ⁸⁷Sr/⁸⁶Sr. These chronostratigraphically well-controlled dates improve the calibration of the Silurian time scale and provide the first determinations of the rates of biogeochemical change during the Ludlow Epoch.

Publication Information

Cramer, Bradley D.; Schmitz, Mark D.; Huff, Warren D.; and Bergström, Stig M.. (2015). "High-Precision U-Pb Zircon Age Constraints on the Duration of Rapid Biogeochemical Events During the Ludlow Epoch (Silurian Period)". Journal of the Geological Society, 172(2), 157-160. https://doi.org/10.1144/jgs2014-094