准噶尔盆地卡姆斯特地区石树沟群砂岩地球化学特征及其对源岩的指示

Geochemical Characteristics of Sandstone of the Shishugou Group and Its Implication to Source Rock in the Kamusite Area,Junggar Basin

为揭示卡姆斯特地区石树沟群的源岩性质和构造背景,探讨其对砂岩型铀成矿作用的影响,对该区的石树沟群砂岩开展了岩石学及地球化学研究。结果表明,石树沟群砂岩以岩屑砂岩为主,成熟度低,富集Cs、U、Cr、Hf,亏损Nb、Ta、Th;整体具轻稀土富集、重稀土亏损、Eu负异常特征,与卡拉麦里造山带中酸性岩浆岩稀土元素特征具有相似性;沉积物源为卡拉麦里造山带,源岩主要为富铀的中酸性岩浆岩,形成构造背景为活动大陆边缘-大陆岛弧环境。石树沟群的源岩为砂岩型铀成矿提供了物质来源。

To reveal the source rock properties and tectonic setting of the Shishugou group in the Kamusite area,and discuss the influence of the source rock and tectonic setting on sandstone type uranium mineralization,petrology and geochemistry studies were carried out on the sandstone of the Shishugou group in this area.The results indicate that the sandstone of the Shishugou group is mainly composed of lithic sandstone with low maturity,and enrichment of Cs,U,Cr,Hf,loss of Nb,Ta,Th.The sandstone is characterized by enrichment in light rare earth,depletion in heavy rare earth with negative Eu anomaly,which is similar to the REE characteristics of intermediate acid magmatic rocks in the Karamaili orogenic belt.The sediment source is the Karamaili orogenic belt,and the source rock is mainly uranium rich intermediate acid magmatic rock,and the tectonic setting is an active continental margin continental island arc environment.The source rocks of the Shishugou group provide material sources for sandstone type uranium mineralization.