Abstract:

The carbonate platform developed on the Yangtze block during the Hercynian-Indosinian stage. Platform margin depositional system developed in the southern carbonate platform including four sedimentary types: the beach of carbonate platform margin, the reef platform of carbonate platform margin, platform margin slope and the sea between beach (reef). According to development characteristics of platform margin, four stages can be divided: the platform margin strip distributed along the line of Mile-Shizong-Qinglong-Nandan-Hechi during the Middle Devonian-Late Devonian(SS1), the reefbank of platform margin developed widely; the platform margin strip distributed along the line of Qinglong-Liupanshui-Anshun during the Early Carboniferous-early Early Permian(SS2-SS3), platform margin beach developed widely; the platform margin strip distributed along the line of Zhenfeng-Ziyun-Luodian-Hechi-Liuzhou during the the late Early Permian-Late Permian(SS4), the reef-bank of platform margin developed widely; the platform margin strip distributed along the line of Zhenfeng-Guiyang-Fuquan during Early Triassic-Middle Triassic(SS5), platform margin oolitic beach developed in the the Early Triassic, platform margin dominated reef developed in the Late Triassic. The study proved that horizontal migration of platform margin was mainly controlled by syndepositional faults, the vertical sequence evolution of platform margin was mainly controlled by sealevel change, the type of margin reef-bank was controlled by different types of carbonate secret organisms.

Key words: carbonate platform margin, sedimentary type, syndepositional fault, Hercynian-Indosinian stage, Upper-Yangtze region