Geochemical Records of Paleoenvironment Associated with the Middle Triassic Luoping Biota, Yunnan, Southwest China

摘要

INTRODUCTION The Luoping Biota, recently discovered from Member Ⅱ of the Middle Triassic Guanling Formation in Yunnan Province, SW China (Zhang et al., 2008, Fig. 1), was assigned to the Pelsonian substage of the Anisian on the basis of its occurrence within the Nicoraella kockeli Zone (Zhang et al., 2009). The fossiliferous strata mainly consist of gray-black thin-bedded micritic limestone, with high organic content and many pyrite granules. It has been found that geochemical characteristics of limestone are also important indicators to the paleoenvironmental conditions (Chang et al., 2009; Jing et al., 2005; Rimmer, 2004; Wang, 2003; Nan et al., 1998; Jones and Manning, 1994). To understand the paleoenvironmental conditions associated with the Luoping Biota, major and trace elements of 51 fresh samples collected from the Dawazi Section were analyzed.