四川海子山地区水系沉积物铀钍地球化学特征

发布时间：2018-05-14 08:32

本文选题：海子山 + 水系沉积物　；参考：《成都理工大学》2017年硕士论文

【摘要】：研究区位于西南三江成矿带之义敦岛弧褶皱带中南段,在研究工作开展之前,先大量且完整地收集前人的研究资料,阅读大量有关文献,把现有的研究成果以及地质资料有机的融合分析,通过开展海子山地区1比5万水系沉积物测量工作,以铀钍地球化学行为特征为切入点,探讨了研究区铀钍元素的分布特征以及分配特征,结合区域岩体地球化学特征以及构造、地层特征,对研究区U、Th异常物源区进行了分析,再结合前人的成矿理论及地质背景,圈定了U、Th成矿远景区,据此对研究区内的成矿远景分析进行了分析,为研究区地质矿产勘查的进一步研究提供一定的理论与现实依据。通过水系沉积物测量共圈定单元素异常10处,其中U元素7处、Th元素3处。对研究区铀钍元素的异常分布进行分析,结果显示,受区内巨大花岗岩体的影响较为明显,在地层与花岗岩体的接触带附近,分布着铀钍元素的主要异常。根据U、Th地球化学性质,结合地形地貌以及地质背景,分析了U、Th的地球化学行为特征,结果表明,研究区水系沉积物U、Th含量自绒依措花岗岩体以及格聂哈嘎拉花岗岩体向外围海拔低的区域逐渐降低,U/Th比值基本同步变化。研究了U、Th地球化学异常的源区。利用岩石的U、Th比值来从定量的角度厘定岩石现测铀含量(U)和原始铀含量(Uo),通过计算得出,研究区绒依措岩石的近代铀变化系数(△U),结果表明:绒依措花岗岩的原始铀含量是相对较高,为3.36×10-6~14.03×10-6,平均为9.81×10-6。此外,△U变化也较大(-25.89%~-42.35%),但主要表现为近代铀被带走,这两者能够充分证明绒依措花岗岩体为海子山地区水系沉积物的U异常提供了活性铀源。对研究区铀钍元素的富集系数、浓集系数以及变异系数的特征进行了一系列的统计分析。结果显示,铀钍元素的含量背景值在本区内很高,且富集性和分异性都很强,故研究区具较大的成矿潜力,其中,就浓集和分异特征而论,铀元素表现尤为突出。综合分析研究区的地质背景以及已查明的矿种,最终推测本区找矿前景相对较好的为铀矿床,其中花岗岩型铀矿床为主要找矿对象。分析了地质单元含矿性。结果显示,测区含矿性较好的地质单元为三叠系图姆沟组和燕山晚期第一阶段侵入岩岩体范围,现有的矿点和矿化点均分布在三叠系图姆沟组范围内,反映了燕山晚期第一阶段侵入岩岩浆热液作用,并最终在三叠系图姆沟组的富集成矿,指示了本区的成矿作用的时代性和层控性。在上述研究的基础上对本区的成矿远景进行了评价,划分出2个找矿靶区,B级1个,C级1个。自南至北大致划分两个成矿远景区,分别为鄂纳-赤格U、Th找矿远景区和琼达-海子山U、Th等找矿远景区,为以后的找矿工作提供了较为详实的信息。
[Abstract]:The research area is located in the middle and south section of the Yidong Island Arc fold belt in the Sanjiang metallogenic belt in southwest China. Before the research work was carried out, a large number of previous research materials were collected and a large number of related documents were read. Based on the existing research results and the organic fusion analysis of geological data, by carrying out 1: 50, 000 river system sediment survey in the Haizishan area, the geochemical behavior characteristics of uranium and thorium are taken as the breakthrough point. The distribution and distribution characteristics of uranium and thorium elements in the study area are discussed. In combination with the geochemical characteristics of the regional rock mass and the structural and stratigraphic characteristics, the source area of the Uttrium anomaly in the study area is analyzed, and then the metallogenic theory and geological background of the predecessors are combined. The metallogenic prospect of the study area is analyzed, which provides a theoretical and practical basis for the further study of geological and mineral exploration in the study area. In this paper, 10 anomalies of common order elements were measured by water system sediment, of which 7 were U elements and 3 were Th elements. The anomalous distribution of uranium and thorium elements in the study area is analyzed. The results show that the influence of granitic bodies is obvious, and the main anomalies of uranium and thorium elements are distributed near the contact zone between strata and granite bodies. According to the geochemical properties of Uth, combined with topographic and geomorphological and geological background, the geochemical behavior characteristics of Uth are analyzed. The results show that, In the study area, the UU / Th content in the sediments of the river system gradually decreased synchronously from the low elevation area of the Rongyicuo granite body and the Gniehagala granite body to the peripheral area. The source region of the Th geochemical anomaly is studied. Using the UT ratio of rock to determine the present measured uranium content (U) and the original uranium content of the rock from a quantitative point of view, it is found that, In the study area, the recent uranium variation coefficient (UT) of the Ruiyicuo rock shows that the original uranium content of the Rongyicuo granite is relatively high, which is 3.36 脳 10-6 (14.03 脳 10-6), with an average of 9.81 脳 10-6. In addition, the U variation is also larger, but mainly because the uranium is taken away in modern times, both of which can fully prove that the Rongyicuo granite provides a source of active uranium for the U anomaly in the sediments of the Haizishan area. The characteristics of enrichment coefficient, concentration coefficient and variation coefficient of uranium and thorium elements in the study area were analyzed. The results show that the background value of uranium and thorium content is very high in this area, and the enrichment and heterogeneity are very strong. Therefore, the study area has great metallogenic potential, especially in terms of concentration and differentiation characteristics. Based on the comprehensive analysis of the geological background and the known ore species in the study area, it is concluded that the uranium deposit in this area has a relatively good prospect, among which the granite-type uranium deposit is the main prospecting object. The ore-bearing properties of geological units are analyzed. The results show that the geological units with good ore-bearing property are the Tumgou formation of Triassic and the intrusive rock mass of the first stage of late Yanshanian. The existing ore points and mineralization points are distributed in the range of Tumgou formation of Triassic system. It reflects the magmatic hydrothermal process of intrusive rocks in the first stage of the late Yanshanian and finally enriched and metallogenic in the Triassic Tumgou formation indicating the epoch and stratification of mineralization in this area. On the basis of the above research, the metallogenic prospect of this area is evaluated, and two prospecting target areas are divided into B class and C class. From the south to the north, there are two ore forming scenic spots, one is Ena-Chige UTh Prospecting area, the other is Jongda-Haizi Mountain UTh Prospecting area, which provides more detailed information for the future ore prospecting work.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P619.1;P632.3

【参考文献】