The Irtysh shear zone (ISZ) of Altai region is the lineament structure of the collision suture type, where granites of Kalba complex and granodiorites of Zmeinogorsk complex are exposed to regional gneiss formation an...The Irtysh shear zone (ISZ) of Altai region is the lineament structure of the collision suture type, where granites of Kalba complex and granodiorites of Zmeinogorsk complex are exposed to regional gneiss formation and stress metamorphic alterations. This study is based on detailed structural observations at special grounds using optical and electron microscopy, and on the behavior analysis of isotopic systems from altered granitoids.Within the ISZ area we have established the continuous rows of granitoid stress metamorphism from initial recrystallization of protolite, its cataclasis and mechanical flaring up to complete recrystallization with alteration of mineral composition and formation of the streaky complexes of granite tectonites of blastomylonite and blastocataclasite types. The directed alteration of rocks has several impulse and is expressed by a change in morphology of mineral grains and their relations, magnification of deformation component in the rock structure, and formation of new mineral phases on the basis of initial ones without surface fluidization. At transformation of isotopic systems from granitoid, their feldspars, biotite and hornblende, we can observe “rejuvenation” of the rock substrate from 270-290 Ma for Kalba granitoids to 220-235 Ma for their tectonites, and for Rudny Altai granodiorites, their ages changes from 285-317 Ma to 232-257 Ma for their tectonites.展开更多
The research on Paleozoic tectonics and endogenic metallogeny in the Tianshan-Altay region of Central Asia is an important and significant project. The Altay region, as a collision zone of the Early Paleozoic （500-39...The research on Paleozoic tectonics and endogenic metallogeny in the Tianshan-Altay region of Central Asia is an important and significant project. The Altay region, as a collision zone of the Early Paleozoic （500-397 Ma）, and the Tianshan region, as a collision zone of the early period in the Late Paleozoic （Late Devonian-Early Carboniferous, 385-323 Ma）, are all the result of nearly N-S trending shortening and collision （according to recent magnetic orientation）. In the Late Devonian-Early Carboniferous period （385-323 Ma）, regional NW trending faults displayed features of dextral strike-slip motion in the Altay and Junggar regions. In the Tianshan region, nearly EW-trending regional faults are motions of the thrusts. However, in the Late Carboniferous-Early Permian period （323-260 Ma）, influenced by the long-distance effect induced from the Ural collision zone, those areas suffered weaker eastward compression, the existing NW trending faults converted into sinistral strike-slip in the Altay and Junggar regions, and the existing nearly E-W trending faults transferred into dextral strike-slip faults in the Tianshan region. The Rocks of those regions in the Late Carboniferous-Early Permian period （323-260 Ma） were moderately ruptured to a certain tension-shear, and thus formed a number of world famous giant endogenic metal ore deposits in the Tianshan-Altay region. As to the Central Asian continent, the most powerful collision period may not coincide with the most favorable endogenic metallogenic period. It should be treated to ＂the orogenic metallogeny hypothesis＂ with caution in that region.展开更多
文摘The Irtysh shear zone (ISZ) of Altai region is the lineament structure of the collision suture type, where granites of Kalba complex and granodiorites of Zmeinogorsk complex are exposed to regional gneiss formation and stress metamorphic alterations. This study is based on detailed structural observations at special grounds using optical and electron microscopy, and on the behavior analysis of isotopic systems from altered granitoids.Within the ISZ area we have established the continuous rows of granitoid stress metamorphism from initial recrystallization of protolite, its cataclasis and mechanical flaring up to complete recrystallization with alteration of mineral composition and formation of the streaky complexes of granite tectonites of blastomylonite and blastocataclasite types. The directed alteration of rocks has several impulse and is expressed by a change in morphology of mineral grains and their relations, magnification of deformation component in the rock structure, and formation of new mineral phases on the basis of initial ones without surface fluidization. At transformation of isotopic systems from granitoid, their feldspars, biotite and hornblende, we can observe “rejuvenation” of the rock substrate from 270-290 Ma for Kalba granitoids to 220-235 Ma for their tectonites, and for Rudny Altai granodiorites, their ages changes from 285-317 Ma to 232-257 Ma for their tectonites.
文摘The research on Paleozoic tectonics and endogenic metallogeny in the Tianshan-Altay region of Central Asia is an important and significant project. The Altay region, as a collision zone of the Early Paleozoic （500-397 Ma）, and the Tianshan region, as a collision zone of the early period in the Late Paleozoic （Late Devonian-Early Carboniferous, 385-323 Ma）, are all the result of nearly N-S trending shortening and collision （according to recent magnetic orientation）. In the Late Devonian-Early Carboniferous period （385-323 Ma）, regional NW trending faults displayed features of dextral strike-slip motion in the Altay and Junggar regions. In the Tianshan region, nearly EW-trending regional faults are motions of the thrusts. However, in the Late Carboniferous-Early Permian period （323-260 Ma）, influenced by the long-distance effect induced from the Ural collision zone, those areas suffered weaker eastward compression, the existing NW trending faults converted into sinistral strike-slip in the Altay and Junggar regions, and the existing nearly E-W trending faults transferred into dextral strike-slip faults in the Tianshan region. The Rocks of those regions in the Late Carboniferous-Early Permian period （323-260 Ma） were moderately ruptured to a certain tension-shear, and thus formed a number of world famous giant endogenic metal ore deposits in the Tianshan-Altay region. As to the Central Asian continent, the most powerful collision period may not coincide with the most favorable endogenic metallogenic period. It should be treated to ＂the orogenic metallogeny hypothesis＂ with caution in that region.
