黑龙江科洛杂岩变形特征、阶段和意义

发布时间：2018-07-03 07:42

本文选题：科洛杂岩 + 晚三叠世　；参考：《大地构造与成矿学》2017年04期

【摘要】：兴蒙造山区东段的科洛地区,自古亚洲洋关闭之后,经历了复杂的多阶段陆内变形,每一期变形都具有不同的机制,均是中国东北中生代以来板块边缘重要构造事件的反映。三叠纪中晚期,科洛杂岩经历了上盘指向NNE方向的韧性挤压变形,相关变形分布在整个科洛杂岩地区,大量低角度石英拉伸线理以及A型褶皱枢纽均指示了松嫩地块NNE向的运动,科洛杂岩也在此时形成。科洛杂岩并不是松嫩地块的基底,而是中生代构造事件的变质产物,该期事件不是古亚洲洋关闭后的造山带伸展,而与来自东侧和南侧的挤压有关。晚侏罗世-早白垩世科洛地区左行韧性走滑是蒙古-鄂霍茨克洋的关闭所致,其变形集中在科洛杂岩的西部边界剪切带上。白垩纪时科洛杂岩受到伸展构造的改造,以一系列向南东倒伏、走向NNE-SSW的相似褶皱为特征,褶皱的倒伏向不随位置的变化而改变,其伸展不是典型的变质核杂岩。新生代科洛杂岩又受到了近SN向的挤压,发生区域性的宽缓褶皱变形。
[Abstract]:Since the closure of the Paleo-Asian Ocean, the Coro area in the eastern part of Xingmenzao Mountain area has undergone complex intra-continental deformation, each of which has different mechanisms, which is a reflection of the important tectonic events on the margin of the plate since the Mesozoic in Northeast China. In the middle and late Triassic, the Koluo complex experienced ductile compression deformation pointing to NNE direction in the upper face, and the related deformation was distributed throughout the Koluo complex area. A large number of low-angle quartz extensional lineages and A-type fold hubs indicate the NNE movement of the Songnen block and the Koluo complex is formed at this time. The Coro complex is not the basement of the Songnen block, but the metamorphic product of the Mesozoic tectonic event, which is not the extension of the orogenic belt after the closure of the Paleo-Asian Ocean, but is related to the compression from the east and south. The late Jurassic-early Cretaceous ductile strike-slip in the Kolo area is caused by the closure of the Mongolia-Okhotsk Ocean, and its deformation is concentrated in the western boundary shear zone of the Coro complex. During the Cretaceous period, the Koluo complex was altered by extensional structures, characterized by a series of similar folds lying south to east and striking NNE-SSW. The inverted direction of the folds did not change with the change of position, and its extension was not a typical metamorphic core complex. The Cenozoic Koluo complex was squeezed in the near SN direction, resulting in regional wide and slow fold deformation.
【作者单位】：中国地质科学院地质研究所;中国科学院新疆生态与地理研究所;
【基金】：国家重点基础研究发展计划(2015CB453002) 中国地质调查局项目(12120113096400)联合资助
【分类号】：P542

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