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| Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan, Northwest China: Evidence from sandstone detrital and geochemical records | |
| 作者姓名： | LI Zhong GUO Hong WANG Daoxuan & LIN Wei . Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China . Tarim Oilfield Branch CNPC Korla China . Hefei University of Industry Tunxilu Hefei China |
| 作者单位： | LI Zhong1，GUO Hong2，WANG Daoxuan3 & LIN Wei1 1. Institute of Geology and Geophysics，Chinese Academy of Sciences，Beijing 100029，China 2. Tarim Oilfield Branch，CNPC，Korla 841000，China; 3. Hefei University of Industry，Tunxilu 193，Hefei 230009，China |
| 基金项目： | 国家自然科学基金，国家重点基础研究发展计划(973计划) |
| 摘 要： | Succeeding to multiply collisions of different blocks in Late Paleozoic1―5], complex intracontinental structural deformation occurred in the Tianshan area during Mesozoic-Cenozoic6―16], which controlled coeval basin-range evolution and resulted in intensive modi- fication and adjustment of the Paleozoic oil-gas reser- voirs17―19]. The Kuqa Depression is a secendary struc- tural unit of the Tarim basin, in which Mesozoic- Ce- nozoic deposits occur in thickness of 6000―7000 m. The Kuq… |
| 收稿时间： | 31 March 2010 |
Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan, Northwest China: Evidence from sandstone detrital and geochemical records |
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| LI Zhong,GUO Hong,WANG Daoxuan & LIN Wei . Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing ,China . Tarim Oilfield Branch,CNPC,Korla ,China, . Hefei University of Industry,Tunxilu ,Hefei ,China.Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan, Northwest China: Evidence from sandstone detrital and geochemical records[J].Science in China(Earth Sciences),2005,48(9):1387-1402. | |
| Authors: | LI Zhong GUO Hong WANG Daoxuan LIN Wei |
| Institution: | 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2. Tarim Oilfield Branch, CNPC, Korla 841000, China 3. Hefei University of Industry, Tunxilu 193, Hefei 230009, China |
| Abstract: | Similar to compositional evolution of sandstone modes and detrital heavy minerals from different profiles in the Kuqa Depression, Northwest China, major element analysis of whole sandstones from the same profiles shows four discontinuous depositional interfaces or periods, respectively corresponding to Lower Triassic\Middle Triassic, Upper Jurassic\Lower Cretaceous, Lower Cretaceous\Paleogene and Miocene\Pliocene, and indicates five-phase evolution during Mesozoic-Cenozoic: (1) From the first to fifth phase, a depositional suite changes from maroon and coarse clastic, through grey-dark grey and fine, red and coarse, red-mottled, interlayered by gypsum, to brown and coarse clastic assemblages, accompanying detrital component evolution in unstable-stable-unstable-very unstable-very unstable assem- blages. It is indicated that carbonate and complex detritus gradually dominate in sandstones in post-Late Jurassic, with rapid reduction of compositional maturity. (2) For major element geo- chemical parameters of whole sandstones, CaO and Fe2 O * 3+MgO contents show a change sequence in high-low-high-higher-highest values, with rapid increasing in post-Late Jurassic. (3) Contra some aggregative indicators for weathering indexes of sandstone detrital component, Al2O3/(CaO+Na2O) and ln(Q/(L+CE)), show a change sequence in low-high-low-lower-lowest ratios, with rapid decreasing in post-Late Jurassic. It is found that sandstone samples of the first, second and later three phases may be distinguished from the A-CN-K and A-CNK-FM diagrams respectively. Therefore, in the Kuqa Depression-Tianshan, the most important discontinuous depositional interface recording paleotectonic and paleoclimatic transition occurred in Early Triassic\Middle Triassic and Late Jurassic\Early Cretaceous, respectively, and, however, tec- tonic differentiations of basin-range system finally result in distinct depositional systems but similar detrital weathering indexes across the Lower Cretaceous\Paleogene and Miocene\ Plio- cene interfaces, respectively. |
| Keywords: | Tianshan Kuqa Depression basin-range depositional record tectonic transition Mesozoic-Cenozoic |
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