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    东准噶尔奥依托浪格地区原三塘湖组陆相火山岩地层的重新厘定与解体

    Redetermination and disintegration of the continental volcanic strata of the former Santanghu Formation in Oetonggar area, Eastern Junggar Basin

    • 摘要: 笔者通过岩性组合与岩相组合对比研究、SHRIMP锆石U-Pb测年与化石年代学研究等手段,认为东准噶尔奥依托浪格地区原三塘湖组陆相火山岩应重新厘定为巴塔玛依内山组,并建议将这套准噶尔盆地东北缘广泛分布的陆相火山岩根据地质时代解体为巴塔玛依内山组与三塘湖组,三塘湖组仅代表早二叠纪陆相火山岩。年代学研究表明:奥依托浪格地区巴塔玛依内山组年龄具有穿时性,下段年龄为(335.6±6.5)Ma,上段年龄为(320.5±7.1)Ma,属早石炭世晚期到晚石炭世,解决了巴塔玛依内山组长久以来的下、上石炭统之争。综合研究认为:这套陆相火山岩属于东准噶尔构造带自西向东链式缝合背景下的构造-岩浆活动,残余洋盆消失至陆相火山活动开启,同时受到西侧拉张环境与东侧岛弧环境的影响。奥依托浪格地区巴塔玛依内山组火山机构、构造、喷发间歇期发育,具有石油地质意义。

       

      Abstract: In this paper,the authors studied the comparison between lithologic assemblage and lithofacies assemblage SHIRIMP zircon U-Pb dating results and fossil chronology,and believed that the continental volcanic rocks of the former Santanghu Formation in Oetonggar area of Eastern Junggar Basin should be redefined as the Batamayineishan Formation. It is suggested that the widely distributed continental volcanic rocks at the northeast edge of Junggar Basin should be decomposed into the Batamayineishan Formation and the Santanghu Formation according to the geological age. The Santanghu Formation only represents the early Permian continental volcanic rocks. The study of chronology shows that the age of the Batamayineishan Formation in Oetolanagar is time-penetrating. The age of the first lithologic segment is (335.6±6.5)Ma,and the age of the second lithologic segment is (320.5±7.1)Ma,suggesting that the rocks belong to the late lower Carboniferous period to the upper Carboniferous period. Thus,the dispute over the lower and upper Carboniferous system for the Batamayineishan Formation has been solved. According to the comprehensive study,this set of continental volcanic rocks belongs to tectono-magmatic activities in the East Junggar tectonic belt from west to east under the background of chain suture. The residual ocean basin disappeared until the beginning of continental volcanic activity; in addition,it was affected by the tension environment on the western side and the island arc environment on the eastern side. Volcanic mechanisms,structures,and intermittent eruptions of the Batamayineishan Formation in the Oetanagar region suggest that it has petroleum geological significance.

       

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