The Genetic Mechanism of the Sequence Stratigraphy of the Rift Lacustrine Basin in Jiyang Depression, East China

摘要

Through the studies of sequence stratigraphy of early Tertiaryrnin the east part of Jiyang depression, the characteristics ofrnsequence evolution in continental basin of fault depressionrnwere analyzed theoretically, and a series of sequencernstratigraphy patterns and study methods that are suitable to therncontinental fault depression were summed up. According tornhydrogeologic characters,lacustrine basins can be divided intornopen and closed basin with different characters of relative lakernlevel changes. The changes of the lake level are mainlyrncontrolled by tectonic up-down warping in open basin. But inrnclosed basin the changes of the lake level controlled byrnclimate changes. The formation and the characters of therncontinental rift sequence are mainly controlled by tectonicrnmovements and climate changes. So the sequences ofrncontinental lacustrine basin can be divided into tectonicrnsequence and climatic sequence. Moreover, tectonic sequencernis divided into simple, synsedimentary and multi-time faultrndepression sequence. Different kinds of sequence haverndifferent type of system tracts. Periodic changes of climaternlead to lake-level changes in lacustrine, and then it controlledrnthe formation of climatic sequence which are composed ofrnlacustrine lowstand system tracts(LLST), lacustrine extensionrnsystem tracts(LEST), lacustrine highstand systemrntracts(LHST) and lacustrine contraction system tracts (LCST).