Stratigraphic Framework of Jurassic Period and Early Cretaceous in Luozha, South Tibet: including the function of essential sequence law of the regional geological survey

According to the law of Milankovitch Cycles in the perpendicularity,the depositional sequences which lay on the verge of the Neo-Tethys Ocean,north Himalaya continent can be divided into three sequences with type-Ⅱand eighteen sequences with type-Ⅲ from Jurassic Period to Early Cretaceous.Lowstand System Tracts of Early and Metaphse Jurassic Period was undergrown,of which Transgressive Systems Tract and Highstand Systems Tract made up .And then Late Jurassic Period,it shaped huge incised valley,sea level had sunk deeply, Early Jurassic Period changed into Shelf Systems Tract.Therefore, it is established that the stratigraphic framework of Jurassic Period and Early Cretaceous.Based on the 1∶250,000 and the 1∶50,000 regional geological survey mapping,the essential sequences of Lithostratigraphic unit will change the static description into the dynamic law survey of basal sequences,which elucidates the relationship of essential sequence law and sequence stratum.