The Characteristics Of Tectonostratigraphy In Arykum Graben,Kazakhstan

South Turkey basin is a continental rift basin which has a dual structure of rift and depression and former researchers made a detail study of the basin.Based on the results,the part of exploration work has completed and 17 oil and gas fields have already found since the beginning of the exploration in South Turkey basin,twentieth Century.However,the previous works are all based on data of local block and lack of the study under the whole regional construction background.It leads to the result that the knowledge of the control of structure to strata deposition is inaccurate.To solve this problem,this new research guided by the rule of tectonostratigraphy.Tectonic layers have redivided by using 2D seismic data,3Dseismic data and drilling data of Aryskum graben.The tectonic layer of faulted period is composed of Lower Jurassic Bozingen Formation to Middle Jurassic Karagansay Formation,the tectonic layer of fault-depression transformation period is composed of Upper Jurassic Kumkol Formation and Akshabluk Formation,the tectonic layer of depression period is composed of Lower Crataceous Aryskum Formation and Lower Dauls Formation.Afterwards,the tectonic layer of faulted period is divided into three tectonic sublayers by using seismic data.The first tectonic sublayer is composed of total Lower Jurassic strata,the second tectonic sublayer is composed of Lower Jurassic Doshan Formation,the third tectonic sublayer is composed of Middle Jurassic Karagansay Formation.Based on the division of structural layers,a detailed study of slope and the sedimentary type in each construction period of Aryskum graben is taken.The clear correspondence of slope and the sedimentary type in each construction period is established.Finally,the fact that the filling pattern of strata and the spread of depositional system is control by the specific type of slope and its distribution has confirmed.In fault period,the rift activity is strong,most of the type of slope is steep slope.The specific type of slope determines the filling pattern of strata is messy,and sedimentary types are submarine fan and fan delta.In fault-depression transformation period,the activity of the rift became slow,the slope gradient became small.It determines the filling pattern of strata is divergent or onlap.The sedimentary types are braided river delta and delta.In depression period,the activity of the rift has stopped,the type of slope change to a deposition slope which is broad and gentle.In this period,most of the filling pattern of strata is divergent or parallel and sedimentary types are delta and rivers.