CAJ | 학술논문

详细的地质解剖工作表明,东天山地区大南湖岛弧带石炭纪出露4套岩石地层组合,即早石炭世小热泉子组火山岩、晚石炭世底坎儿组碎屑岩和碳酸盐岩、晚石炭世企鹅山组火山岩、晚石炭世脐山组碎屑岩夹碳酸盐岩.根据其岩石组合、岩石地球化学、生物化石、同位素资料以及彼此的产出关系,认为这4套岩石地层组合的沉积环境分别为岛弧、残余海盆、岛弧和弧后盆地.结合区域资料重塑了大南湖岛弧带晚古生代的构造格架及演化模式.早、晚石炭世的4套岩石地层组合并置体现了东天山的复杂增生过程.
상세적지질해부공작표명,동천산지구대남호도호대석탄기출로4투암석지층조합,즉조석탄세소열천자조화산암、만석탄세저감인조쇄설암화탄산염암、만석탄세기아산조화산암、만석탄세제산조쇄설암협탄산염암.근거기암석조합、암석지구화학、생물화석、동위소자료이급피차적산출관계,인위저4투암석지층조합적침적배경분별위도호、잔여해분、도호화호후분지.결합구역자료중소료대남호도호대만고생대적구조격가급연화모식.조、만석탄세적4투암석지층조합병치체현료동천산적복잡증생과정.
Located in the southern margin of Tuha basin within the East Tianshan Mountains, Dananhu arc is famous for hosting Tuwu porphyry Cu deposits. It is important for us to deepen our understanding of the genesis of porphyry deposits and the tectonic evolution in the whole East Tianshan area. Based on detailed geological mapping, the authors recognized four lithostratigraphic associations in the Carboniferous Dananhu arc belt within the East Tianshan Mountains, i.e., the Lower Carboniferous Xiaorequanzi Formation consisting mainly of volcanic rocks, the Upper Carboniferous Dikan'er Formation composed of clastic rocks intercalated with carbonate, the Upper Carboniferous Qi'eshan Formation comprising volcanic rocks, and the Upper Carboniferous Qishan Formation of clastic and carbonate rocks. Their rock associations, geochemistry, fossils and spatial relationship together with previously published geochronological data suggest that the previously-thought Dananhu arc is actually made of arc volcanic rocks, back-arc basin sediments and remnant oceanic basin sediments, which are associated with the above-mentioned four units respectively. Thus, the tectonic and evolution framework has been established in association with regional studies. There existed at least two ocean-continent transformation stages (i.e., Late Devonian and Late Carboniferous) in the East Tianshan Mountains in Late Paleozoic. The marine deposit of Early Carboniferous Xiaorequanzi volcanic rocks was formed by ocean-ocean subduction in the Kangur Ocean far away from the Devonian active continental margin. The collision between marine volcanic rocks and the Tarim active continental margin (central Tianshan block) formed the Late Carboniferous remnant oceanic basin together with the subduction polarity reversal. The northern ocean basin began the S-dipping subduction towards the Early Carboniferous volcanic rocks and formed the Late Carboniferous Qi'eshan volcanic arc and Qishan back-arc basin. The final collision suture is Dacaotan fault between Tarim plate and Dananhu arc. The Carboniferous lithologic associations of Dananhu arc indicate that the East Tianshan Mountains may represent a complex archipelago-ocean basin, and this orogeny involved fore-arc accretion and back-arc basin closure during the whole orogenic process. Juxtaposition of different tectonic units implies that the East Tianshan Mountains orogeny was probably a multiple accretionary orogenic process.