| 松辽盆地钱家店铀矿含铀岩系层序地层结构对铀成矿的约束 |
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| 引用本文： | 曹民强.松辽盆地钱家店铀矿含铀岩系层序地层结构对铀成矿的约束[J].地质科技通报,2021,40(4):131-142. |
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| 作者姓名： | 曹民强 |
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| 基金项目： | 国家重点研发计划项目2018YFC0604205 |
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| 摘 要： | 弄清楚砂岩型铀矿含铀岩系地层结构及其对铀成矿的制约作用，是准确认识铀成矿规律和成矿作用的基础。综合地震、测井、岩心及分析测试资料，对松辽盆地西南部钱家店铀矿床含铀岩系——姚家组层序地层结构进行了研究，在此基础上，探讨了地层结构与铀成矿的关系。研究发现，钱家店地区姚家组为一个完整的三级层序，姚家组底界面为区域不整合界面，底部主要发育泥砾岩、含泥砾砂岩等，姚家组顶界为平行不整合，顶部发育一套紫红色夹灰色泥岩，在姚家组内部识别出了初始湖泛面和最大湖泛面，将其划分为低位体系域、湖泊扩展体系域和高位体系域。低位体系域分布范围较小，厚度平均约40 m，呈北东狭长型分布；湖泊扩展体系域和高位体系域地层连续超覆，分布范围向西南扩展至八仙筒-开鲁一带，总体仍为北东走向，地层平均厚度在研究区分别约为85 m和75 m。层序地层结构对研究区姚家组铀成矿具有约束作用，垂向上，由下至上不同小层序组铀矿化逐渐减弱；平面上，不同体系域铀矿化分布特征不同，低位体系域铀矿化主要发育在钱Ⅳ块-钱Ⅴ一带，呈北东走向条带状分布，矿体呈似板状、透镜状；湖泊扩展体系域铀矿化在钱Ⅱ-钱Ⅳ-钱Ⅴ一带呈不规则弧形分布，矿体呈"似卷状"，为典型的层间氧化带型铀矿化；高位体系域铀矿化主要发育在钱Ⅲ块以及南部零星分布，推测向南具有进一步找矿空间。研究结果可为研究区找矿提供依据，并为铀成矿模式及成矿过程研究提供基础。
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| 关 键 词： | 层序地层 姚家组 钱家店铀矿床 铀成矿 |
| 收稿时间： | 2020-10-13 |
Constraints of the sequence stratigraphic structure of uranium-bearing series on mineralization in Qianjiadian uranium deposit,Songliao Basin |
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| Abstract: | Understanding the stratigraphic structure of uranium-bearing rock series in sandstone-type uranium deposits and its constraints on uranium mineralization is the basis of understanding the uranium metallogenic regularity and mineralization. In this paper, the sequence stratigraphic structure of the uranium-bearing series in Qianjiadian uranium deposit, southwest Songliao Basin, is studied based on seismic, well logging, core analysis and test data. The relationship between stratigraphic structure and uranium mineralization is discussed. It is found that the Yaojia Formation in Qianjiadian area is a complete third-order sequence. The bottom boundary of Yaojia Formation is a regional unconformity and the bottom part of Yaojia Formation is composed of mud conglomerate and sandstone with mud pebble. The top boundary of Yaojia Formation is a parallel unconformity, and the top part of Yaojia Formation comprise mauve mixed with gray mudstone. The initial flooding surface and the largest flooding surface have been recognized internally, which is divided into low system tract, transgressive system tract and high system tract. The low system tract distributes in a small area with an average thickness of about 40 meters, showing a long and narrow north-east distribution. The transgressive system tract and the high system tract continuously overlap, and the distribution area extends southwest to the Baxian Tube-Kailu County area, and the overall direction is still north-east. The average formation thickness in the study area is 85m and 75m respectively. The uranium mineralization of the Yaojia Formation in the study area is restrained by the sequence stratigraphic structure, and the uranium mineralization of the different small sequence groups from the bottom to the top gradually weakens in the vertical direction. On the plane, the distribution characteristics of uranium mineralization are different in different system tracts. The uranium mineralization in the low system tract mainly develops in the area of QianⅣ-QianⅤ.The ore bodies are plate-like and lenticular in shape, and are distributed in a north-east strike strip. Uranium mineralization in transgressive system tract in the Qian Ⅱ, Qian Ⅳ and Qian Ⅴ is irregular arc-shaped and the ore bodies are "roll-like", which is classical interlayer oxidation zone uranium mineralization. The uranium mineralization in high system tract mainly develops in Qian III and sporadic distribution in the south, and it is speculated that there is further prospecting space to the south. The study results can provide a basis for prospecting in the study area, and a basis for the study of uranium metallogenic model and process. |
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