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High-precision u–pb zircon age constraints on the duration of rapid biogeochemical events during the ludlow epoch (Silurian period)
Journal article   Peer reviewed

High-precision u–pb zircon age constraints on the duration of rapid biogeochemical events during the ludlow epoch (Silurian period)

Bradley D Cramer, Mark D Schmitz, Warren D Huff and Stig M Bergström
Journal of the Geological Society, Vol.172(2), pp.157-160
2015
DOI: 10.1144/jgs2014-094
url
https://figshare.com/articles/journal_contribution/High-precision_U_Pb_zircon_age_constraints_on_the_duration_of_rapid_biogeochemical_events_during_the_Ludlow_Epoch_Silurian___Period_/3453869View
Open Access

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 206 Pb/ 238 U 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 87 Sr/ 86 Sr. 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. Supplementary material: U–Pb geochemical methods, data and CL imagery are available at http://www.geolsoc.org.uk/SUP18798.

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