Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the ...Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by “flower” strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269±5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.展开更多
During the collision between India and Eurasia, the continental compression and shorten is thought to be absorbed by the way of thickening of the Tibetan plateau crust and strike\|slip extrusion outwardly of blocks su...During the collision between India and Eurasia, the continental compression and shorten is thought to be absorbed by the way of thickening of the Tibetan plateau crust and strike\|slip extrusion outwardly of blocks surrounding the Tibetan plateau. A series of models have been proposed recently, of which the most typical one is continental blocks extrusion by Tapponnier et al.. Virtually previous studies show that the Red River—Ailaoshan fault is the eastern boundary of extrusion Indochina displaced southward relative to South China about 23 Ma ago, and more, the western boundary of extrusion blocks is inferred to be Sijie fault in the eastern Burma. But the movement age of Sijie fault is around 13 Ma inferred from the age of Andeman Sea formation and different from that of the Red River—Ailaoshan fault. It is an important scientific problem where the western boundary of extrusion blocks is.展开更多
文摘Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by “flower” strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269±5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.
文摘During the collision between India and Eurasia, the continental compression and shorten is thought to be absorbed by the way of thickening of the Tibetan plateau crust and strike\|slip extrusion outwardly of blocks surrounding the Tibetan plateau. A series of models have been proposed recently, of which the most typical one is continental blocks extrusion by Tapponnier et al.. Virtually previous studies show that the Red River—Ailaoshan fault is the eastern boundary of extrusion Indochina displaced southward relative to South China about 23 Ma ago, and more, the western boundary of extrusion blocks is inferred to be Sijie fault in the eastern Burma. But the movement age of Sijie fault is around 13 Ma inferred from the age of Andeman Sea formation and different from that of the Red River—Ailaoshan fault. It is an important scientific problem where the western boundary of extrusion blocks is.
