Paleoproterozoic Positive δ¹³C Excursion in Henan, China

Abstract

A positive δ ¹³C excursion in Palaeoproterozoic carbonate sequences in Henan, China is reported in this paper. Carbon isotope analyses of samples from Wuzhiling and Huayu Formation of Songshan Group, a well-preserved Palaeoproterozoic-carbonate sequences in northern Henan, China present δ ¹³C values range from −1.0‰ to 4.2‰_PDB, with a mean at 2.5‰_PDB. Results of microscope observation, oxygen isotope, and Mn/Sr ratio indicate that Wuzhiling Formation suffered stronger alternation than Huayu, which suggested a higher initial δ ¹³C excursion of Wuzhiling Formation than present known value. The positive δ ¹³C_carb excursions of Wuzhiling Formation support the Lamagundi Event as early oxygenation of the terrestrial environment, was also recorded in Palaeoproterozoic carbonate sequences in Henan, China.

Keywords:

• positive δ¹³C excursion
• Henan/China
• Paleoproterozoic
• atmospheric oxygenation

Acknowledgments

This work was supported by the National Basic Research Program of China (973 Program, No. 2007 CB815601). We are grateful to Prof. Guan Baode and Dr. Zhao Taiping for providing help to sample. We wish to thank Prof. Chen Yanjing and Dr. Liu Jun for their critical reading of an earlier version of this manuscript and providing the constructive opinions for the article.