The Evolution Of Structure And Sediment & Their Correlation Of Cambrian-Ordovician In TaZhong Area, Tarim Basin

Bsaed on the theory of Tectonics,Structure,Sedmentology,Sequence stratigraphy andBasin analysis,the paper analysis the feature of structure ,deposition and correlation aboutthem in Cambrian-Ordovician in Center of Tarim by comprehensive utilize various data suchas outcrop,log,core,sesmic data, we get the reviews below these:1.From the lower to the upper, we divided the unconformity into 7 order surface whichrepresents 7 structure layers;the sequence of (Sinian)Cambrian—Quaternary in TaZhongarea can be divided into 3 megasequence sets: (1) (Sinian)Cambrian—Middle Devonianextension—compression cycle of the paleo-Asian ocean;(2)Upper Devonian—lowerPermian extension—compression cycle of paleo-Tethys ocean;(3)MiddlePermian—Neogene extension—compression cycle of Neo—Tethys.Tarim basin shows thecharacter of compounding structure.2.There are five structure stytles in TaZhong in Cambrian-Ordovician. From Cambrianto middle Ordovician, the domain style was entensional, from upper Ordovician,there werecompression,strike-slip and gravity structure.With the changed of paleo-stress, three wasinverted structure style in TaZhong area which including positive & negative structure. Thestructure style showed compressing .3.The framework of basement controlled the framework of sedimentary cover and thelatter showed "it was divided into block from east to west and into belt from south to north".It has layer structure in vertical and fault in horizontial and they were recombination indifferent situs. TaZhong showed schollen integral.4.Most faults in TaZhong showed the trait of inversion. Transfer zone developed in thisarea and manifested as displacement transfer zone,blind fault,"Z"coherence and laceratefault et.al. These transfer zone adjusted the structure style and the framework.5.The key sequence borders in lower Paleozoic were T74,T70.They were controlled by keytectonic events and displayed composite. They were lithological—temporal border anddisplayed difference on different sectonic position.6.The depositional system of Cambrian-Ordovician were controlled bye thepaleo-structure. They were divided into 3 depositional system such as mesa,continentalshelf,deep sea basin and 9 sedimentary facie.7.The slope-break developed in Cambrian-Ordovician in Tarim basin.4 stage slope-breakdeveloped in upper Ordovician and they controlled the depositional system simultaneous.The reef were affected by paleostructure.