BASIC CHARACTERISTICS OF THE SILURIAN OF GUANGXI

The Silurian System of Guangxi is completely developed in southern and southeastern Guangxi, the lower, middle and upper series being all present. It is composed of a sequence of bathyal and abyssal flysch and flyschoid clastic rocks, more than 7,000 m in thickness, containing an abundance of graptolites. In Qinzhou and Yulin the Upper Silurian displays conformable contacts with the Early Devonian Monograptus uniformis （graptolite）-bearing strata, while in the vicinity of Cenxi the Lower Devonian containing Qujinolepis sp. （fish fossil）has conformable contacts with the Upper Silurian containing Protathyris sp. （brachiopod）. This is of important significance in the study of the distri- bution of the Caledonian-Variscan geosyncline in southern Guangxi, Silurian- Devonian boundary and nature of the Guangxi movement. 19 graptolite zones have been established in the Silurian System of Guang xi; from below upwards they are the Glyptograptus persculptus, Akidograp- tus acuminatus, Pristiograptus cyphus, Demirastrites tsiangulatus, D. convolu- tus, Monograptus sedgwickii, Spirograptus turriculatus, Streptograptus crispus, Monoclimacis griestoniensis, Stomatograptus grandis, Cyrtograptus angustus, C. murchisoni, Monograptus riccartonensis, Pristiograptus dubius, P. vulgaris, Pristiograptus nilssoni, P. tumescens, P. ultimus and P. transgrediens zones. Studies indicate that the Silurian terrigenous clastic rocks in Guangxi belong to turbidites and that there exist Early Silurian abyssal turbidites in Beiliu county, Guangxi.