辽南晚中生代以来的剥露冷却历史  

The exhumation and cooling history in the southern Liaodong Peninsula since Late Mesozoic

作　　者：陈慧 刘建辉[1,2] 丁正江 孙敬博 金巍[1] CHEN Hui;LIU Jianhui;DING Zhengjiang;SUN Jingbo;JIN Wei(Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Beijing 100037,China;No.6 Institute of Geology and Mineral Resources Exploration of Shandong Province,Weihai,Shandong 264209,China)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]自然资源部深地动力学重点实验室,北京100037 [3]山东省第六地质矿产勘查院,山东威海264209

出　　处：《地质学报》2022年第4期1163-1181,共19页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42172218,41772195);中国地调局地质调查项目(编号DD20190358,DD20221646);自然资源部深地动力学重点实验室自主研究课题(编号J1901-34)联合资助的成果。

摘　　要：古太平洋/太平洋板块与欧亚大陆的持续相互作用不仅引发了中国东部强烈的构造变形及岩浆活动,而且使古老而稳定的华北克拉通东部陆块岩石圈在中生代发生减薄、去克拉通化和破坏,并诱发克拉通地壳的持续拉张与减薄。为了更好地理解华北克拉通破坏后地壳持续拉张减薄过程及机制,本文利用锆石/磷灰石(U-Th)/He及裂变径迹等多种低温热年代学方法,结合锆石及磷灰石的U-Pb年龄,对辽东半岛南缘的剥露冷却历史开展了研究。来自5个花岗质岩石样品的磷灰石裂变径迹数据、磷灰石及锆石(U-Th)/He年龄数据及热历史模拟揭示了辽东半岛南缘经历了约120~95 Ma、85~70 Ma及始于55~40 Ma的三期快速剥露冷却作用,它们分别对应华北克拉通及中国东部晚中生代以来的三期伸展变形,可能归因于晚中生代以来古太平洋/太平洋板块向欧亚大陆的持续幕式俯冲、后撤及地幔物质上涌诱发的华北克拉通东部陆块岩石圈减薄和破坏,以及克拉通破坏后地壳的多期伸展变形及幕式拉张减薄作用。The continuous interaction between Paleo-Pacific/Pacific plate and Eurasian continent has not only caused strong structural deformation and magmatic activity in the eastern China, but also contributed to lithospheric thinning, decratonization and destruction of the ancient and stable eastern North China Craton(NCC) in the Mesozoic, and induced continuous crustal extension and thinning following the destruction. In this study, we have conducted study on the cooling and exhumation history of the southern Liaodong Peninsula using various low-temperature thermochronologic methods, including zircon and apatite(U-Th)/He dating and fission track analyses, combined with zircon and apatite U-Pb ages, in order to understand the history and mechanism of the continuous crustal extension and thinning after the destruction of the NCC. The apatite fission track(AFT) and apatite/zircon(U-Th)/He data of the five granitic samples collected from the southern Liaodong Peninsula and AFT thermal modeling for four representative samples unraveled that the southern Liaodong Peninsula experienced three stages of rapid cooling and exhumation during ~ 120~95 Ma, 85~70 Ma and 55~40 Ma, which well correspond to the three stages of extensional deformation occurred in the NCC as well as eastern China since the Late Mesozoic, this may be attributed to the lithospheric thinning and destruction of the eastern NCC, and continuous multi-stage crustal extension and episodic thinning following the destruction, triggered by the continuous episodic retreating subduction of the Paleo-Pacific/Pacific plate towards Eurasian continent and subsequent mantle upwelling since the Late Mesozoic.

关 键 词：华北克拉通 辽东半岛 剥露冷却 伸展变形 低温热年代学 

分 类 号：P534.5[天文地球—古生物学与地层学] P597.3[天文地球—地质学] P542