摘要
Penglaiba section of the Kalpin area,Tarim Basin, serves as a typical section for Cambrian research, whereas no detailed carbon isotopic research on the Cambrian Series 2-Series 3 boundary has been documented up to date. Carbon isotope analyses were carried out on the carbonate rocks of Cambrian Series 2 (Wusongger Formation)-Series 3 (Shayilik Formation) transition in the Penglaiba section. The δ13C values (V-PDB) vary between -4.2‰ and 0.8‰, while the δ18O values (V-PDB) vary between-7.4‰ and -3.8‰. Moreover, there is no obvious correlation between the δ13C and δ18O values, indicating the δ13C values recorded a memory of ancient seawater chemistry. A large negative δ13C excursion up to -4.2‰ at the boundary between the Wusongger and Shayilik formations characterize the Cambrian Series 2-Series 3 boundary.
