Sequence Stratigraphy of Devonian and It Controls Deposits in Intraplate Basin,South China

The intraplate basin of Devonian in South China formed by collsion between Yangtze Plate and Huaxia Plate during Caledonian tectonic cycle. From bottom to top, the strata of Devonian rnuld be divided into four depositional sequences: The first sequence rnnsists of sediments from the Lochkovian to Middle Emsian period. The sedimentary strata of terrertsial facies from Lochkovian to Pragian period rnuld be the lwstand systems tract (LST) formed during sea level fall in post一orogeny.“its bax surface belonged to type I sequence boundary unrnnformity. The distribution of sedimentary body, the conglomerate and sandy shall of Lian一Huashan Fororation and the lower part of Na Gaoling Formation belonged to overlap sediments and lowstand fan which were formed by stream reworking of eluvial material located at erosion surface; in western Guangxi: The LST consists of violet一red sandy rnnglomerate and sandstone in center of Guangxi but lack of in orthern Guangxi and southern Hunan. The transgressive systems tract (TST) consists of terrigenous clastic rock of littoral and tidal flat facies. The condensed section (CS) was made up of brachiopod biostrome in middle part of Maiqu Formation. The highstand systems tract (HST) composed of sandstone and mudstone. The second depositional sequence consists of sediments from the late Emsian to Early一Middle Givertian period. The base boundary line of this sequence shows type I sequence boundary unconformity and erosion surface and rejuvenation of stream. The top sequence boundary shows palaeokarst. The LST has been found in Guangxi. The TST consists of terrigenous clastic rock of littoral facies, biomicrite, bioclastic limestone and shale and carbonate rock of reef and bank facies. The CS composed of biostrome. The HST consists of reefal limestone,bioclastic hmPaLOne. micrite and dolostone.