An extremely brief end Ordovician mass extinction linked to abrupt onset of glaciation

• Published in: Solid earth sciences Vol. 4; no. 4; pp. 190 - 198
• Main Authors: Ling, Ming-Xing, Zhan, Ren-Bin, Wang, Guang-Xu, Wang, Yi, Amelin, Yuri, Tang, Peng, Liu, Jian-Bo, Jin, Jisuo, Huang, Bing, Wu, Rong-Chang, Xue, Shuo, Fu, Bin, Bennett, Vickie C., Wei, Xin, Luan, Xiao-Cong, Finnegan, Seth, Harper, David A.T., Rong, Jia-Yu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2019; Elsevier
• Subjects: End Ordovician mass extinction (EOME); Hirnantian stage; ID-TIMS; K-bentonite; K-bentonite; Hirnantian stage; ID-TIMS; End Ordovician mass extinction (EOME)
• ISSN: 2451-912X; 2451-912X
• DOI: 10.1016/j.sesci.2019.11.001

The end Ordovician mass extinction (EOME) was the second most severe biotic crisis in Phanerozoic, and has been widely linked to a major glaciation. However, robust geochronology of this interval is still lacking. Here we present four successive high-precision zircon U–Pb dates by isotope dilution thermal ionization mass spectrometry (ID-TIMS) for biostratigraphically well-constrained K-bentonites of a continuous Ordovician-Silurian boundary section at Wanhe, SW China. They include 444.65 ± 0.22 Ma (middle Dicellograptus complexus Biozone), 444.06 ± 0.20 Ma (lower Paraorthograptus pacificus Biozone), 443.81 ± 0.24 Ma (upper Tangyagraptus typicus Subzone), and 442.99 ± 0.17 Ma (upper Metabolograptus extraordinarius Biozone). Calculations based on sedimentation rates suggest a duration of 0.47 ± 0.34 Ma for the Hirnantian Stage, which is much shorter than previously thought (1.4 ± 2.05 Ma in the International Chronostratigraphic Chart ver. 2019/05). The new data also constrain the Hirnantian glacial maximum to ∼0.2 Ma, supporting that its brevity and intensity probably triggered the EOME.