北秦岭陕西华阳川地区铀矿物质来源

    The source of uranium minerals in Huayangchuan area of North Qinling

    • 摘要: 华阳川铀矿床位于老牛山岩体与华山岩体夹持部位,矿体严格受控于NW—SE向华阳川脆韧性剪切带,赋矿岩石以石英碳酸岩为主,伟晶岩次之。关于华阳川铀矿床的物质来源一直没有较可信的研究成果。系统收集航放、地质、钻探、选冶试验等资料,采用地表放射性物探、地质、锆石U-Pb定年等手段,计算各地质体(单元)的放射性能谱特征、年龄特征,研究岩体、脉岩的构造展布规律和放射性元素的迁移规律,揭示华阳川铀矿的成矿物质来源。地表伽玛能谱特征显示,华山岩体翁峪花岗岩U含量为4.82×10-6~6.46×10-6,Th含量为23.03×10-6~31.08×10-6,Th/U值为5.29~6.00;老牛山岩体主要岩石单元U含量为9.27×10-6~11.18×10-6,Th含量为24.39×10-6~27.72×10-6,Th/U值为2.64~3.55,两者均具有高铀、高钍的特征;地球化学特征显示,华山岩体与老牛山岩体均具有埃达克质岩的特征,为不同期次的同源富铀体,但华山岩体翁峪花岗岩有较明显的铀源体特征;放射性航空物探特征显示,华阳川矿区韧性剪切带中具有铀迁入富集特征;地质年代背景研究显示,华山岩体翁峪花岗岩与华阳川矿区含矿石英碳酸岩成岩年龄基本一致,均形成于235~200 Ma;构造背景研究显示,第一次造陆事件(约1800 Ma)至印支期形成的多期次脆韧性剪切带底部直接与华山岩体连通,为活化铀的迁移提供了有利通道。研究表明,华山岩体翁峪花岗岩中的U元素被活化、迁移后,为华阳川铀矿提供了大量的铀源。

       

      Abstract: The Huayangchuan uranium deposit is located at the sandwiched part of the Laoniushan and the Huashan pluton.The ore body is strictly controlled by the NW-SE-trending Huayangchuan brittle-ductile shear zone.The ore-bearing rocks are mainly quartz carbonatite, followed by pegmatite.There have been no more credible research results on the material source of Huayangchuan uranium deposit.This study systematically collected airborne, geological, drilling, and metallurgical data, and used surface radioactive geophysical prospecting, geology, zircon U-Pb dating and other methods to calculate the radioactive energy spectrum characteristics and age characteristics of each plastid body (unit), study the structure distribution law of rock mass and dyke rock and the migration law of radioactive elements, and reveal the source of ore-forming materials of Huayangchuan uranium deposit.The characteristics of the surface gamma spectrum show that the content of the Wengyu granite of the Huashan pluton is 4.82×10-6~6.46×10-6, the thorium content is 23.03×10-6~31.08×10-6, and the Th/U ratios are 5.29~6.00.The uranium content of the main rock units of the Niushan pluton is 9.27×10-6~11.18×10-6, the thorium content is 24.39×10-6~27.72×10-6, the Th/U ratios are 2.64~3.55, both of which have the characteristics of high uranium and thorium.Geochemical characteristics of the Huashan pluton and the Laoniushan pluton are similar to adakitic rocks, which are the same source and rich uranium bodies of different stages.However, the Wengyu granite of the Huashan pluton has obvious uranium source characteristics.Radioactive aerial geophysical characteristics show that the ductile shear zone in Huayangchuan mining area has the characteristics of uranium migration and enrichment.Based on the geochronological background research, the diagenetic age of the Wengyu granite of the Huashan pluton is the same as that of the ore-bearing quartz carbonate in the Huayangchuan mining area, both formed in 235~200 Ma.The bottom of the multi-stage sub-brittle-ductile shear zone which is formed from the first land-making event (ca.1800 Ma) to the Indosinian period is directly connected to the Huashan pluton, which provides favorable conditions for the migration of activated uranium.Combined the above research, the author believes that after the uranium element in the Wengyu granite of the Huashan Pluton is activated and migrated, it provides a large amount of uranium source for the Huayangchuan uranium deposit.

       

    /

    返回文章
    返回