Depositional System Distribution Characteristics In Sequene Stratigraphic Framework Of Tangyuan Fault Basin And Sequence Stratigraphic Models Establishment

Tuanyuan fault basin is the most northern subordinate tectonic part of the Yishu graben. The boundaries of Tangyuan fault basin are controlled by the two northeastren parallel deep faults (F1 and F2). Inside of the Tangyuan fault basin, faults developed very much, they dissected the basin to many parts. Presenting format of zonating (eastern hollow zone,central uplift belt,western hollow zone,western ramp region)from east to west and blocking (five fault block)from south to north. seeing that tectonic setup, the basin is studied by choosning the third block that hasing central uplift belt and the fifth block hasing no central uplift belt.Because of the limited datum , so the original analyse parasequence groups (systems tract),sequence by drilling core,well logging,seismic and and conecting with logging bar diagram and so on methords, and analyse parasequence only by drilling core,well logging ; the typical identifing signs of sequence : lithofacies surface of discontinuity of drilling core, appearing scarp numeric alternation of logging bar, lower cutting valley,onlap,truncation of seismic; the typical identifing signs of systems tract : primary lake pano-surface (LST andTST),the largest lake pano-surface (TST and HST) and parasequence overlying fashion ; the typical identifing signs of parasequence : lake pano-surface is peak and base interface of parasequence (lithology surface of discontinuity between sandrock and mudstone ), infundibular of logging bar is correspondent one parasequence.In the base of identifying sequence interface, I choose severl seismic inline profiles cross well and utilize above-mentioned methords to establish sequence framewoeke of Xinancun group and Dalianhe group in Tangyuan fault basin . about dividing sequence stratigraphy unit , the original adopt fourfold classification of Liu Zhaojun(2002) ,that is lowstand systems tract,transgressive system tract,higstand system tract,reliction system tract . So I establish sequence strtygraphic framework of Xinancun - Dalianhe in Tangyuan fault basin, Xinancun group and Dalianhe group are divided to four sequences,,two sequences for everyone group.There are two different physiognomy : developing middle uplifted area and no developing middle uplifted area, developing middle uplifted area the original maily analyse deposit system assemblage type of different systems to the third block that developing middle uplifted area and the fifth block hasing no central uplift belt in the fault basin. The deposit system type mostely are fan delta,ake,gravity flow. The three deposit system hasing different assemblage types in different positions of basin. Fan delta,lake is in gentle slop, lake,gravity flow,fan delta are in deep water of gentle slop, fan delta,meare are in uplift belt, fan delta,gravity flow in gentle slop of uplift belt, alluvial fan,fan delta are in steep gradient, fan delta,lake,gravity flow are in deep water of steep gradient. according to above conclusion to establishing sequence stratigraphy model of Tangyuan fanult basin.