BIOSTRATIGRAPHIC SUBDIVISION AND CORRELATION OF EARLY ORDOVICIAN CHITINOZOANS AND ACRITARCHS IN YIYANG, HUNAN

Chitinozoans and acritarchs are reported from the Late Tremadocian to early Floian graptolitic shales in the Nanba Section of the Yiyang area in the Hunan Province.Three chitinozoan biozones and three acritarch assemblage zones are distinguished.The co-exsiting of graptilites,chitinozoans together with acritarchs allows precise calibration between the chitinozoan biozones and acritarch assemblages versus the reference graptolite biozones.The succession of the Late Tremadocian-early Floian chitinozoans and acritarchs from the Jiangnan Slope not only allows precise correlation at both regional and global scale,but also has some palaeogeographical implication refers to this time interval.