Absence of Middle Permian Kamura Event in the Paleo-Tethys Ocean

摘要

INTRODUCTION One of the largest mass extinctions occurred at the end of the Middle Permian (Jin et al., 1994; Stanley and Yang, 1994). It was supposed recently that this mass extinction might occur a little earlier, and was in the middle of the Capitanian (Wignall et al., 2009). The oceanic geochemistry of the Capitanian interval is thus important for us to recover the process of this mass extinction. Previous works on the carbonate carbon isotope composition (δ13Ccarb) mainly focused on the transition period from Middle to Late Permian (Wang et al., 2004). Recently, Isozaki et al. (2007a) recognized a Capitanian (late Guadalupian) high positive plateau, as high as 6‰ to 7‰, of δ13Ccarb in the Panthalassanic Ocean and called it the 'Kamura event'. His later work suggested that this event started in the early Capitanian (low part of Yabeina zone) and lasted as long as 3-4 million years (Isozaki et al.,2007b).