Timing and processes of late Mesozoic mid-lower-crustal extension in continental NE Asia and implications for the tectonic setting of the destruction of the North China Craton: Mainly constrained by zircon U–Pb ages from metamorphic core complexes
Timing and processes of late Mesozoic mid-lower-crustal extension in continental NE Asia and implications for the tectonic setting of the destruction of the North China Craton: Mainly constrained by zircon U–Pb ages from metamorphic core complexes
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DOI：
10.1016/j.lithos.2012.07.020
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发表时间：
2012-12
期刊：
影响因子：
3.5
通讯作者：
Tao Wang;Lei Guo;Yadong Zheng;T. Donskaya;D. Gladkochub;L. Zeng;Jianbo Li;Yanbing Wang;A. M
中科院分区：
文献类型：
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作者：
Tao Wang;Lei Guo;Yadong Zheng;T. Donskaya;D. Gladkochub;L. Zeng;Jianbo Li;Yanbing Wang;A. M
晚中生代亚洲大陆东北部发生了大规模的地壳伸展，变质核杂岩是该地区的主要特征。本文给出了这些mcc中黑云母和角闪石的新锆石U-Pb和Ar-Ar年龄，并结合前人研究的年代学数据，试图确定中-下地壳韧性伸展的起始、持续和结束时间。这些mcc具有相似的40ar /39Ar黑云母和角闪石年龄（130 ~ 110Ma，主要为130 ~ 120Ma），可解释为冷却年龄，代表了mcc晚期形成的时间。部分MCCs同步-后运动侵入体的锆石U-Pb年龄表明，中-下地壳伸展可能始于约150 ~ 145ma，峰值出现在145 ~ 130ma，并持续到130 ~ 120ma，比40ar /39Ar年龄的推断要早10 ~ 20ma。晚侏罗世（150 ~ 145ma）早期延性伸展极有可能在蒙古和中国北部较深层开始，然后向南扩展（140 ~ 130ma），最终发展到整个东北亚大陆（130 ~ 120ma）。根据伸展的时间和过程，提出了华北克拉通破坏的地球动力学模型和构造背景。
Late Mesozoic large-scale crustal extension occurred across the northeastern section of continental Asia, and metamorphic core complexes (MCCs) are the major features in this region. This paper presents new zircon U–Pb and Ar–Ar ages of biotite and hornblende for pre- or syn- (mylonitized) and post-kinematic (unmylonitized) intrusions from these MCCs, and attempts to determine the timing of initiation, duration and termination of the mid-lower-crustal ductile extension by integrating with geochronological data from previous studies. These MCCs have similar40Ar/39Ar biotite and hornblende ages (130 to 110Ma, mainly from 130 to 120Ma), which are interpreted as the cooling ages and represent the timing of the late-stage formation of the MCCs. Zircon U–Pb ages for syn- to post-kinematic intrusions from some MCCs suggest that the mid-lower-crustal extension probably initiated at ca. 150–145Ma with a peak occurring 145–130Ma and continued to 130–120Ma, which is older than that suggested by40Ar/39Ar ages by 10–20Ma. The early ductile extension most likely initiated in Mongolia and northern China during the Late Jurassic (150–145Ma) at a deeper level, then propagated southwards (140–130Ma), and finally developed throughout the entire continental NE Asia (130–120Ma). Based on the timing and processes of the extension, a geodynamic model and tectonic setting of the destruction of the North China Craton (NCC) are proposed.