Preliminary dating of the Viluy traps (Eastern Siberia) : eruption at the time of Late Denovian extinction events ?

• Main Authors: Courtillot, V., Kravchinsky, V.A., Quidelleur, X., Renne, P.R, Gladkochub, D.P.
• Other Authors: Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Sciences de la Terre, de l'Environnement et des Planètes (STEP), Université Paris Diderot - Paris 7 (UPD7), Department of Physics Edmonton, University of Alberta, Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Planetary Science UC Berkeley (EPS), University of California Berkeley (UC Berkeley), University of California (UC)-University of California (UC), Berkeley Geochronology Center (BGC), Melnikov Permafrost Institut, Russian Academy of Sciences Moscow (RAS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Renne; renne; Siberia
• Online Access: https://hal.science/hal-00545487

International audience In this short note, we report new age determinations from four samples of the Middle-Paleozoic Viluy Traps in Siberia, east of the more famous Permo-Triassic Siberian Traps. These samples, which were collected from three drill cores, have been analyzed in parallel and independently in the Orsay (France) and Berkeley Geochronology Center (BGC; USA) geochronology laboratories, using respectively the Cassignol-Gillot K-Ar and the Ar-40/Ar-39 techniques. Dating these samples as a concerted effort in two independent laboratories working jointly on their interpretation is a rather rare yet very valuable exercise. With the K-Ar technique, ages ranging from 338 to 367 Ma with uncertainties on the order of 5 Ma were obtained. With the Ar-40/Ar-39 technique, integrated ages range from 344 to 367 Ma, with uncertainties on the order of 1 Ma, and two samples yielded plateaus, i.e. the best determined ages, at 360.3 +/- 0.9 and 370.0 +/- 0.7 Ma. Three out of four ages yielded by the two separate methods are in agreement within uncertainties. One sample yields incompatible ages and could be from a later, altered dyke event. The Ar-40/Ar-39 plateau age of 370.0 0.7 Ma (conventional calibration) or 373.4 +/- 0.7 Ma (recalculated per Renne et al., 2010), the most reliable age obtained in this study, is compatible with recent determinations of the Late Devonian extinction events at the end-Frasnian (similar to 376 +/- 3 Ma). These results underscore a need for further work, in progress. (C) 2010 Elsevier B.V. All rights reserved.