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Original Article
1.
Introduction
The Mesozoic geology of ENE China is characterized by widespread magmatic rock assemblages, rift basins with sedimentary-volcanic rock sequences and crustal- to lithospheric-scale oblique-slip fault systems with both transtensional and transpressional kinematics (Fig. 1; Ren et al. 2002; Meng, 2003; Wu et al. 2005; Zhang et al. 2010, 2011, 2015; Wang et al. 2011). The distribution and the regional orientation of all these geological features collectively form a strong NNE-SSW-aligned tectonic fabric, superimposed on the Precambrian geology and the ESE-running Qinling-Dabie Orogenic Belt, which developed as a result of the continental collision between the Yangtze Craton (YC) and North China Craton (NCC) during Triassic time. The most extensive magmatic rock assemblages in this region formed during Late Jurassic (165-158 Ma) and Early Cretaceous (132-118 Ma) time.
Figure 1.
(a) Simplified tectonic map of the Jiaodong Peninsula. Abbreviations: NCC - North China Craton; SLOB - Sulu Orogenic Belt; WYF - Wulian-Yantai Fault; YC - Yangtze Craton. (b) Geological map of the Jiaodong Peninsula, showing the distribution of the Precambrian crystalline basement and Triassic UHP metamorphic rocks, Cretaceous sedimentary-volcanic rift sequence and Mesozoic granitoids. Latest early Cretaceous granitoids: 1, Dazeshan; 2, Gushan; 3, Aishan; 4, Yashan; 5, Yuangezhuang; 6, Sanfoshan; 7, Weideshan; 8, Zhaohushan; 9, Laoshan; 10, Xiaozhushan; 11, Dazhushan; 12, Heshan; 13, Shiwaya; 14, Shichang; 15, Wulianshan; 16, Shijiu; 17, Qizishan; 18, Dadian; 19, Dashan; 20, Banquan. Earliest early Cretaceous granitoids: 21, Sanshandao; 22, Xincheng; 23, Shangzhuang; 24, Congjia; 25, Beijie; 26, Guojialing. Late Jurassic Linglong granitic suite: 27, Linglong; 28, Queshan; 29, Kunyushan; 30, Wendeng. Late Triassic Shidao alkaline complex: 31, Jiazishan; 32, Xingjia; 33, Chashan.
[Figure Omitted; See PDF]The Late Jurassic granitic intrusions display a strong deformation fabric represented by a predominantly NNE-SSW-aligned mylonitic foliation and ESE-WNW-trending stretching lineations, consistent with ESE-WNW-directed crustal extension in the region (Fig. 2). Generally NNE-SSW-striking, undeformed Early Cretaceous mafic dyke swarms cross-cut this extensional fabric in the granitic plutons, indicating that much of the extensional ductile deformation must have taken place during Late Jurassic time (Deng & Wang, 2016). A large number of NNE-SSW-oriented metamorphic core complexes with middle to lower crustal rocks also indicate that high-magnitude crustal exhumation was part of this...