AN ENORMOUS THRUST NAPPE AND EXTENSIONAL METAMORPHIC CORE COMPLEX NEWLY DISCOVERED IN SINO-MONGOLIAN BOUNDARY AREA
AN ENORMOUS THRUST NAPPE AND EXTENSIONAL METAMORPHIC CORE COMPLEX NEWLY DISCOVERED IN SINO-MONGOLIAN BOUNDARY AREA
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DOI：
10.1360/yb1991-34-9-1145
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发表时间：
1991-09
影响因子：
9.6
通讯作者：
郑亚东
中科院分区：
文献类型：
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作者：
郑亚东
最近在内蒙古海西—印支造山带内发现了一个巨大的逆冲推覆体和一个伸展成因的变质核杂岩。这两个特征都属于中生代，但前者更古老。逆冲推覆构造向西西-东西走向，元古宙白云岩向南逆冲于寒武系至三叠系地层之上。推力的可见位移约为70公里，推导出的推力位移超过140公里。变质核杂岩（主要为糜棱岩）呈北东向伸展，形成穹丘状，位于张拉滑脱断裂下。糜棱岩的叶理面理平缓倾斜，伸展的矿物线理整体上呈俯冲状。各种剪切感标志显示正常的剪切运动。推覆构造和伸展构造在造山后阶段共存，产生了一些重要的问题。
An enormous thrust nappe and a metamorphic core complex of extensional origin have been recently discovered within the Hercynian-Indosinian orogen of Inner Mongolia. Both features are of the Mesozoic age, but the former is older. The thrust nappe strikes WNW-ESE and Proterozoic dolomite was thrust southwards atop strata ranging from the Cambrian to the Triassic in age. The visible displacement of the thrust is ca. 70 km and the deduced one is over 140 km. The metamorphic core complex (mainly mylonites) extends in an N-E direction, forming itself into a dome geometry and lying under an extensional detachment fault. The mylonitic foliation dips gently and the stretching mineral lineation, as a whole, plunges SSE. Various shear sense markers show a normal-sense shear movement. Some significant problems atise from the coexistence of nappe and extensional structures at a postoro-genic stage.