青藏高原东北隅似三联点构造特征
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摘要
在大陆内部，对于一定尺度的构造块体，似三联点构造是一种较普遍的构造形式。由于大陆内部块体旋转的普遍性，似三联点构造可形成顺旋型和逆旋型两种构造型式。随着块体的旋转和构造演化，似三联点逐渐改变原来的形状，在交接构造区内部的沉积和构造变形不断记录着演化过程，因此通过对其研究可了解区域构造演化过程。根据运动学和几何学特点，可以应用似三联点构造的概念研究构造运动和应变的平面分配以及地震活动的规律性。似三联点构造往往是受控于深部构造运动的表层构造形式，三条构造支的活动强度有一定差异。在青藏高原东北隅，北西西向的祁连山左旋挤压构造带和青藏高原东缘右旋剪切带具有深部构造背景，六盘山构造带则偏离深部构造带。
Quasi trijunction is a kind of popular structure with some scale tectonic blocks in continent.Two kinds of quasi trijunction can be formed at the connective area due to rotation of continental blocks,they are clockwise type and anticlockwise type of quasi trijunction.The shape of a quasi trijunction may change gradually accompany with block rotation and tectonic evolution,but,sediment and structure in connective area can record the history of tectonic evolution.Thus,studying a quasi trijunction can recognize regional tectonic evolution. Regional tectonic movement,plane strain partitioning and character of seismic activity can be studied based on kinematic and geometric analysis of a quasi trijunction. Quasi trijunction are surface structure controlled by deep crustal motion.Tectonic activity may different in three branches.In the quasi trijunction of the Northeastern Corner of Qinghai Xizang Plateau,the NWW trending Qilianshan fault zone with sinistral and compressional movement and the NNE trending east edge fault zone of Qinghai Xizang Plateau with dextral movement have deep crustal tectonic background,but,the Liupanshan tectonic zone have divagated from the deep zone.
Quasi trijunction is a kind of popular structure with some scale tectonic blocks in continent.Two kinds of quasi trijunction can be formed at the connective area due to rotation of continental blocks,they are clockwise type and anticlockwise type of quasi trijunction.The shape of a quasi trijunction may change gradually accompany with block rotation and tectonic evolution,but,sediment and structure in connective area can record the history of tectonic evolution.Thus,studying a quasi trijunction can recognize regional tectonic evolution. Regional tectonic movement,plane strain partitioning and character of seismic activity can be studied based on kinematic and geometric analysis of a quasi trijunction. Quasi trijunction are surface structure controlled by deep crustal motion.Tectonic activity may different in three branches.In the quasi trijunction of the Northeastern Corner of Qinghai Xizang Plateau,the NWW trending Qilianshan fault zone with sinistral and compressional movement and the NNE trending east edge fault zone of Qinghai Xizang Plateau with dextral movement have deep crustal tectonic background,but,the Liupanshan tectonic zone have divagated from the deep zone.
引文
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