In accordance with the recent results of several seismic sections accross Takli-makan Desert in length and breadth made jointly by Sino-American geophysicis-ts

the tectonic evolution and division of Tarim Basin have been studied andpresented here.It is considered that three stages in the basin's evolution process may be divided

i.e.

the formation of geosyncline and platform basement during Archaeozoic;the formation of sedimental blanket of platform during Sinian-Paleozoic and the formation of a continental sedimentary basin of Meso-Cenozoic.Among them

the last stage can be further subdivided intoTriassic-Jurassic faulted basin substage

the Cretaceous-Eogene faulted depression substage

the Neogene depression substage and the Quaternary depauperization substage.Thus the basin is recognized to be a superposed complex hydrocarbon-bearing basin with polycycles.According to its structural features

the basin can be divided into eleventectonic units of second-order

i.e.Central uplift

Tabei uplift

Baicheng depres-sion

North depression

Southwest depression and Southeast depression

and Qiemo-Ruoqiang

Kuruktag

Keping

Teklic and Altun faulted uplifts.Source rocksfrom Paleozoic to Tertiary system are well developd in this basin.Among thesetectonic units

Tabei uplift is the best in hydrocarbon potential

followed suc-cessively by Southwest depression

Baicheng depression

North depression

Central uplift and Southeast depression.Taking other hydrocarbon-bearing basinsinto account

Tarim is the fouth largest one in China.