ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    西天山温泉北中新统塔西河组下部砾岩特征及意义

    Characteristics and Significance of Gravels from Miocene Taxihe Formation in Northern Wenquan County of West Tianshan, Xinjiang

    • 摘要: 博乐盆地地处西天山造山带北部,是盆山耦合研究的理想场所。笔者以温泉北阿茨-科茹尔太一带中新统塔西河组为研究对象,进行地层组成、砾石成分、砾石砾径分析,探讨砾岩成因,浅析其构造背景、物源组成及其对沉积型铀矿成矿作用的意义。研究区塔西河组可分为上部的泥岩层、下部的砾岩层。下部砾岩层主要由灰白色花岗岩质角砾岩组成,局部为灰色凝灰岩质角砾岩、浅红色凝灰岩花岗岩质砾岩。砾石结构、成分、对砾径等分析结果显示,下部砾岩层为冲积扇成因,并以泥石流成因为主,局部为冲积河道成因。结合区域地质资料,研究区中新统塔西河组下部砾岩层为西天山始于晚新生代(24~25Ma以来)构造隆升-剥露事件的沉积响应,物源区为盆地北侧的阿拉套山,其所代表的快速抬升事件掀斜较早形成的地层,使花岗岩大面积出露,为前期已形成砂体中铀的二次富集及后期形成的泥岩中铀的富集提供铀源,对泥岩型铀矿、砂岩型铀矿成矿作用具有重要意义。

       

      Abstract: The Bole basin is distributed in the north part of west Tianshan orogenic belt, which is an ideal place for the study of basin-mountain coupling. In northern Wenquan County, the Taxihe Formation can be divided into the upper mudstone layer and the lower conglomerate layer by studying the formation composition and gravel statistics analysis. The stratigraphic characteristics, gravel composition, gravel of the Taxihe Formation have been analyzed to discuss the genesis, tectonic setting, material source of conglomerate layer and its significance for uranium mineralization. The conglomerate layer is mainly composed of gray-white granitic breccia, and parts are gray tuff-breccia and brownish red granite-tuff-conglomerate. The results show that the lower conglomerate layer was formed in alluvial fan, with debris flow as the main cause and local as alluvial channel origin. Combining with the regional geological characteristics, the conglomerate layer is the sedimentary response of the Neocene cooling event of west Tianshan, and its source region is the Alataoshan on the north side of Bole basin. The rapid uplift event represented by the sedimentation of the conglomerate layer is of great significance to the uranium deposits by tilting the former stratum and providing uranium source for the uranium deposits.

       

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