A set of granitic and amphibole mylonite are exposed in the Altyn Tagh fault zone. The preliminary study shows that these rocks are the product of the syntectonic anatexis in the process of the left-lat- eral strike-s...A set of granitic and amphibole mylonite are exposed in the Altyn Tagh fault zone. The preliminary study shows that these rocks are the product of the syntectonic anatexis in the process of the left-lat- eral strike-slip shear, and are the result of the ductile transpression. There are two types of zircon sorted from the mylonite formed with syn-shear anatexis. Among them, one is the anatectic long co-lumnar zircon and another is the residual metamorphic sub-rounded columnar zircon. Two groups of age for single zircon measured by ion microprobe (SHRIMP) are obtained: one is 461-547 Ma for the sub-rounded columnar residual metamorphic zircon, and the other is 239-244 Ma for the long-columnar anatectic zircon. This type of zircon is direc-tionally spread in rock, and the long axis direction of its crystal is identical to that of stretching lineation, represent-ing the direction of tectonic stress in the process of the strike-slip. 40Ar-39Ar age of the directional growth horn-blende in the same mylonite展开更多
基金The work was supported by the National Key Basic Research Project (Grant No. G1998040800) Sino-France Collaborative Project of "Altun Shan-Qilianshan" Tectonic Evolution and Lithosphere Shearing.
文摘A set of granitic and amphibole mylonite are exposed in the Altyn Tagh fault zone. The preliminary study shows that these rocks are the product of the syntectonic anatexis in the process of the left-lat- eral strike-slip shear, and are the result of the ductile transpression. There are two types of zircon sorted from the mylonite formed with syn-shear anatexis. Among them, one is the anatectic long co-lumnar zircon and another is the residual metamorphic sub-rounded columnar zircon. Two groups of age for single zircon measured by ion microprobe (SHRIMP) are obtained: one is 461-547 Ma for the sub-rounded columnar residual metamorphic zircon, and the other is 239-244 Ma for the long-columnar anatectic zircon. This type of zircon is direc-tionally spread in rock, and the long axis direction of its crystal is identical to that of stretching lineation, represent-ing the direction of tectonic stress in the process of the strike-slip. 40Ar-39Ar age of the directional growth horn-blende in the same mylonite
