Tectonic types and evolution of Ordovician proto-type basins in the Tarim region

作     者：HE DengFa1, ZHOU XinYuan2, ZHANG ChaoJun3 & YANG XiaoFa1 1 Energy Resources School, China University of Geosciences, Beijing 100083 2 PetroChina Tarim Oilfield Company, Korla 841000, China 3 Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China 

出 版 物：《Science Bulletin》 (科学通报(英文版))

年 卷 期：2007年第S1期

页      面：164-177页

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

基　　金：the National Key Basic Research and Development Program of China (Grant No. 2006CB202300) 

主　　题：Ordovician period proto-type basin composite basin basin evolution Tarim block 

摘      要：The Ordovician system is an important target for exploration in the Tarim Basin. Restoration of the Ordovician tectono-depositional environment is a key basis for the study of the structural development history in Tarim block and the prediction of the favorable Ordovician reservoir belts (zones). Based on the surrounding tectonic settings, the litho-facies and sedimentary fill, the palaeo-geography, palaeoclimate and palaeo-ecology, and the structural deformation and magmatic eruptions, in this paper we combine the sedimentary fill in the basin with the development of the surrounding orogenic belts and re-build the proto-type basins of the different Ordovician periods. During the Ordovician period, the Tarim region was characterized by the composite of the interior cratonic depression with the peripheral cratonic depression. The interior cratonic depression in the central and western parts is mainly the depositional area of the platform facies while the peripheral cratonic depression in the eastern part is mainly the zone of deepwater basin facies, with the slope acting as the transition belt between them. During the Late Ordovician period, the closure of the Northern Kunlun Ocean and destruction of the trencharc-basin system in the Altyn Tagh region put the southern part of the Tarim block under compression and uplifting and turned the central and western parts of the carbonate platform into the mixed depositional continental shelf. The eastern region of the basin had the over-compensated flysch sedimentation with huge thickness, marking the drastic turn of the basin nature. The basin tectonic framework turned to the south-north differentiation of the Silurian period from the east-west differentiation of the Ordovician period.