Research On Permian In The Hala’alate Mountain, West Junggar

This dissertation is object on the sedimentary and volcanic rocks of Permian in the Hala’alat mountain of Western Junggar, Xinjiang. Studying the features of strata in our researching area synthetically, including spatial distribution, rock association characteristics, the basic sequence of strata, fossil specimens and the contact relationship between each other. Through the several years of our research, gained the achievement as follows:1. Clarify the Permian strata in the Hala’alate mountain through studied of Permian stratigraphic. It is the redefinition Jiamuhe Formation, Baiyanghe Formation from bottom to top.2. Jiamu river is a typical set of Molasse Formation. The lithology mainly include celandine green, lavenderblush, grey brown, brown, variegated thick layer of conglomerate, cobble conglomerate, lenticular conglomerate, conglomerate clip feldspar sandstone, pebbly sandstone, feldspar lithic grit,thick layer of conglomerate nip celadon thin-layer sandstone, contain boulders in boulder conglomerate, coarse sandstone gravel, feldspar lithic sandstone and mottled gravel conglomerate interbed and local with thick sandstone lens. The contact relations with the underlying strata marine facies clastic rock clip volcanic rock of the late Carbnifirious Aladeyikesai Formation is overlap unconformity, and the contact relations with the overlying formation Baiyanghe Formation basic volcanic lava, pyroclastic rocks is angular unconformity,and the contact relations with the diabase strains, dike is intrusive contact relationships. It’s time is Early Permian according to paracalamites stenocostatus, lepidodendron and the relationship with upper and lower strata.3. Baiyanghe Formation is the product of a latest volcanic activity, and it has complete volcano organization form now. The rock assemblage is complete: volcanic vent facies(agglomerate), extrusive facies(volcanic breccia,tuff and a little sedimentary tuff), effusive facies(basalt, and esite), Subvolcanic phase(diabase walls), and the intaction with the Jiamuhe Formation is eruption unconformity. Its time is late early Permian according to the U-Pb dating 279 Ma.4. The ancient tectonic environment analysis: West junggar ocean basin began to close and orogenic belt begin to form because of Kazakhstan plate with Junggar oceanic crust subduction and collision in carboniferous. Form a set of foreland basin properties of Molasse Formation due to orogenic belt nappe from north west to south east on a large scale in Permian,and then further squeeze from north west to south east made the stratum to be fold,and basaltic magma erupted in squeeze the slack period forming the volcanic edifice of Baiyanghe Formation as we can see.