Characteristics of the Tazang tectonic mélange belt

Abstract: By using the method of tectonic slab mapping in the continental orogenic belt, the authors carried out a systematic study of the Tazang tectonic belt of Jiuzhaigou. It is considered that the Tazang tectonic belt is a tectonic mélange belt with distinct northern and southern boundary faults. Its northern boundary is the Yazagou fault striking NW-SE, and the southern boundary is the Heye fault, which also strikes NW-SE. The Tazang tectonic belt extends in a NW-SE direction for as long as ca. 16-24 km with a width of 7-8 km and is composed of three Late Paleozoic and Triassic tectonic slabs (or blocks) of varying sizes and shapes and in faulted contact with sandy slate of the Tazang complex. Generally, there is no order between the slabs and there is order within the slabs. Microscopic deformation features are conspicuous and the three-dimensional finite strain measurements show compression in NE-SW and nearly S-N directions. Analysis of the tectonic environment of the survey area shows that there occurred four phases of deformation.