Deformation history of the Qianlishan Complex, Khondalite Belt, north China: Structures, ages and tectonic implications
Deformation history of the Qianlishan Complex, Khondalite Belt, north China: Structures, ages and tectonic implications
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中国北方孔兹岩带千里山杂岩的变形历史：结构、时代和构造意义
DOI：
10.1016/j.jsg.2020.104176
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发表时间：
2020
影响因子：
3.1
通讯作者：
Shangjing Wu
中科院分区：
文献类型：
--
作者：
Changqing Yin;Hengzhong Qiao;Shoufa Lin;Changcheng Li;Jian Zhang;Jiahui Qian;Shangjing Wu
千里山杂岩是华北陆块西部孔兹岩带中的一个多次变形的麻粒岩杂岩，代表了古元古代陆-陆碰撞造山带。千里山杂岩经历了D1和D2两个主要变形阶段。D1主要产生NWW向翻转至横卧叶内等倾褶皱F1、近水平穿透叶理S1、NNE-SSW矿物线理L1，与顶部至SSW逆冲剪切相关，反映了NNE-SSW挤压导致的地壳增厚。D_1期发育有M_1期和M_2期麻粒岩相变质作用。D2依次叠加于D1构造之上，以NWW-SEE向双倾伏张开为特征，形成紧密直立褶皱F2和较小的近垂直轴向面理/劈理S2。D2期伴随峰后近等温减压（M3），可能与地壳增厚后的折返作用有关。与变形有关的淡色脉岩的西姆斯U-Pb年龄表明，D1普遍出现在1976-1936 Ma，D2随后出现在1936-1854 Ma。这些结果表明，孔兹岩带经历了长期（~ 1亿年）多期变形和高级变质与岩浆活动。时间约束和运动学一致性表明，在1.95Ga左右，阴山地块与鄂尔多斯地块发生北北东-南西西向碰撞，形成西部地块。
The Qianlishan Complex is a multiply deformed granulite terrane of the Khondalite Belt that represents a Paleoproterozoic continent-continent collisional orogen in the Western Block of the North China Craton. Two major stages of deformation (D1and D2) were identified in the Qianlishan Complex. D1mainly produced NWW-trending overturned to recumbent intrafolial isoclinal folds F1, sub-horizontal penetrative foliations S1, NNE-SSW mineral lineations L1associated with top-to-the-SSW thrust shear, reflecting crustal thickening due to the NNE-SSW compression. D1was developed with the prograde (M1) and peak (M2) granulite-facies metamorphism. D2successively superposed the D1structures and was characterized by NWW-SEE-trending doubly plunging open to tight upright folds F2and minor sub-vertical axial planar foliations/cleavages S2. D2was accompanied by post-peak near-isothermal decompression (M3), probably related to exhumation following the crustal thickening. SIMS U–Pb zircon ages of deformation-related leucocratic dykes demonstrate that D1broadly occurred at 1976–1936 Ma and D2subsequently happened at 1936–1854 Ma. These results indicate that the Khondalite Belt underwent long-term (~100 Myr) polyphase deformation and high-grade metamorphism associated with magmatism. Timing constraints and kinematic compatibility suggest that the deformation sequence resulted from the NNE-SSW collision between the Yinshan and Ordos Blocks to form the Western Block at ~1.95 Ga.