Late Mesozoic rifting and its deep dynamic mechanisms in the central Sulu orogenic belt: Records from Lingshan Island  

作　　者：Tengfei ZHOU Yaoqi ZHOU Nina SФAGER Paul Martin HOLM Zhenkai ZHANG Jun WANG Zhao LIANG Hongyu MU Yanjun CHENG Feifei LIU Miao WANG Yue ZHANG Hui ZHANG Yangjian GU Shihui DONG Hanjie ZHAO Manjie LI Yang CHEN Yanzi LIU 

机构地区：[1]School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China [2]Department of Geosciences and Natural Resource Management,University of Copenhagen,Copenhagen-K 1350,Denmark [3]Shandong Provincial Key Laboratory of Deep Oil&Gas,China University of Petroleum(East China),Qingdao 266580,China [4]Shaanxi Center of Mineral Geological Survey,Shaanxi Institute of Geological Survey,Xi'an 710068,China [5]School of Earth Sciences,Yunnan University,Kunming 650500,China [6]Department of Science and Technology,Hebei GEO University,Shijiazhuang 050031,China [7]College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China [8]School of Architectural Engineering,Binzhou University,Binzhou 256500,China [9]Research Institute of Petroleum Exploration and Development,Shengli Oilfield Company,SINOPEC,Dongying 257015,China [10]Key Laboratory of Geological Safety of Coastal Urban Underground Space,Ministry of Natural Resources,Qingdao Geo-Engineering Surveying Institute,Qingdao 266101,China

出　　处：《Science China Earth Sciences》2022年第9期1751-1771,共21页中国科学（地球科学英文版）

基　　金：supported by the Key R&D Plan of Shandong Province (Grant No. 2017CXGC1608);the Project of Department of Science and Technology of Sinopec (Grant No. P20028);the Shandong Natural Science Foundation Youth Fund Project (Grant No. ZR2020QD026);the Fundamental Research Funds for the Central Universities (Grant Nos. 18CX06019A, 19CX05004A)。

摘　　要：The Lingshan Island scientific drill confirms that two episodes(Laiyang period and Qingshan period) of rifting developed in the central Sulu orogenic belt(SOB) in Late Mesozoic. With a set of methods including fieldwork, drilling, core logging, zircon U-Pb dating and whole rock geochemistry applied, the age, the depositional sequence and the deep dynamic mechanisms of rift evolution were unraveled. The stratigraphic sequence of the Laiyang-Qingshan Groups on Lingshan Island was composed of two different rifting sequences:(1) Laiyang Group(147–125 Ma), which consists of deep-water gravity flow deposits with interlayers of intermediate volcanic rocks;and(2) Lower Qingshan Group(125–119 Ma), which unconformably overlies the former sequence and contains subaerial volcanic deposits and terrestrial deposits. The tectonic environment changed during the evolution of these two episodes of rifting: the rift was in a NNW-SSE extensional environment in the Laiyang period and showed the typical passive rifting character that “lithospheric extension and rifting preceded volcanism”. The passive rifting period was ended by a short WNW-ESE compression at about 125 Ma. After that, the tectonic environment transferred to a strong NW-SE extensional environment and the rifting evolved into a volcanic arc basin in the Qingshan period. The igneous rocks are shoshonitic to high-K calc-alkaline trachyandesites to trachytes with a few intercalated lamprophyres and a rhyolite.The geochemical characteristics of the igneous rocks indicate that they are mantle-derived melts with a metasomatized mantle source and/or crustal contamination. In addition, an increased thinning of the lithosphere happened during the rifting episodes.The low-angle subduction of the Paleo-Pacific plate in the Jurassic weakened the thickened SOB lithospheric mantle. The rollback of the subducting plate started in late Jurassic to early Cretaceous, and the SOB lithospheric mantle was delaminated synchronously because of the gravity collapse. Thus, this caused p

关 键 词：Sulu orogenic belt Lingshan Island Late Mesozoic RIFTING Slab subduction Basin dynamics 

分 类 号：P534.5[天文地球—古生物学与地层学] P542[天文地球—地质学]