Carbon Isotope Development in the Ordovician of the Yangtze Gorges Region (South China) and Its Implication for Stratigraphic Correlation and Paleoenvironmental Change

摘要

INTRODUCTION The Ordovician was a critical period in the earth's history. It was rather different in many respects from today (see review in Servais et al., 2010). For example, a greenhouse climate state with high carbon dioxide levels of 8-18 times present atmospheric level was probably a prevailing character of this period (Berner, 2001). In recent years, stable carbon isotope values have been widely used for the stratigraphic division and correlation of Ordovician rocks (e.g. Bergstrom et al., 2008), as well as in paleoenvironmental studies (Bergstrom et al., 2006). A composite carbon isotope curve through the Ordovician was presented by Shields and Veizer (2004) and later by Bergstr(o)m et al.