Abstract:

The comprehensive marine sedimentary environmental model of Chinain late Proterozoic to Triassic periods is established on the basis of twosets of facies,including six facies zones and fifteen facies belts,namely:1,The trough basin facies which includes the deep sea trough-basinand the shallow sea trough-basin facies zones;and 2,The platform shelffacies which includes the shallow sea basin,the plat form margin,the platform and the continental margin facies zones.The shallow sea basin facies zone consists of the shelf margin basin,the shallow shelf and the inner-margin shelf slope facies belts.The plat-form margin facies zone comprises the foreslope,the reef and the bankfacies belts.The platform facies zones comprise the trough-like platform,the open platform,the semi-restricted platform and the restricted plat- form facies belts.The continental margin facies zone includes the lit-toral bar-beach,the tidal flat lagoon,the coastal marsh,the coastalterrigenous clastic beach and the delta facies belts.The marine sedimentary environmental model of China in late Prote-rozoic to Trissic periods can be classified into three types and fifteenforms These are the trough basin type,the platform shelf type and thetrough-platform type.The first one comprises the shallow sea trough-basin,the deep sea trough-basin and the shallow-deep sea trough-basin.The second one includes nine different forms.They are the trough-likeplatform shelf,the open platform shelf,the semi-restricted platformshelf,the restricted platform shelf,the bar-beach platform shelf,thedeltaic platform shelf,the terrigenous clastic beach platform shelf,themargin basin platform shelf and the marsh platform shelf.The third onecomprises the joint form of trough-platform,the forms of platform snr-rounded by troughs and of trough surrounded by platforms.The marine sedimentary environments of China in late Proterozoicto Triassic periods are characterized by the development of continentalmargin facies zone and by the complexity and variousness of platformfacies belts,frequent occurrence of high-energy facies belts,and the pre-sence of source-reservoir-cap combinations in the platform facies zones.