厄立特里亚安塞巴区土壤地球化学特征及找矿远景分析

发布时间：2018-05-07 18:31

  本文选题：安塞巴区 + 异常评序　； 参考：《成都理工大学》2015年硕士论文

【摘要】：厄立特里亚安塞巴区地处阿拉伯-努比亚地盾以南,努比亚地盾内,该地盾由新古元代大陆边缘(公元前870~670兆年)和年轻的洋内岩浆弧岩体组成,受东非大裂谷和红海裂谷的共同作用,该地盾历经了长期而复杂的地质演化过程,具有良好的成矿地质和构造背景,是厄国典型的多金属成矿带。由于受战乱的影响,使本国的矿业发展停止不前,研究区先前的地质工作也很少,主要为一些小比例尺的遥感、物探以及少量的区域地质调查。研究前期的资料发现该区域具有成矿潜力。论文依托于《厄立特里亚安塞巴区Kerkebet金多金属矿勘查》项目,在收集与综合研究前期地质资料的基础上,通过土壤地球化学调查,查明了区内土壤元素的含量和空间分布特征,确定了该区土壤中各元素的异常下限,圈定了单元素及综合异常。结合1:5万地质填图以及前期的地、物、遥资料,圈定找矿远景区并对其做远景分析。综合研究,取得了以下主要成果和认识:1、研究区出露地层主要为新元古界夏甲群(Harga)地层和纳克法群地层(Nakfa),纳克法群是主要的含矿地层,在矿区的东部有该群岩石出露;选区褶皱和断裂较发育,其对成矿都有利,尤其是在断裂交汇部位;矿区出露的岩浆岩主要为基性-酸性岩浆岩,岩体对成矿作用影响较大;选区蚀变较强,主要蚀变为硅化、绢云母化、高岭土化、绿泥石、绿帘石化;选区主要矿产为以锌铜伴生金的多金属块状硫化物矿产、构造热液型金矿以及构造蚀变岩型金矿;2、以研究区的岩石中元素的平均含量为背景,土壤中Mo、Au、Bi、As、Ag、Sb、Cu、Pb、Zn为显著富集元素,W、Ni元素为显著贫乏元素;空间上,Mo、Sb、W、Au、Bi、As的变异系数大于1,为强分异型元素;Cu、Pb、Zn、Co的变异系数大于0.7小于1,为分异型元素。3、通过土壤元素的相关性和聚类统计分析,土壤元素组要分为两类:一类为Au-Bi-Sn-Ag-Sb-Cu-Pb-Zn,此类元素可能为块状硫化物矿的元素组合,另一类为W-Co-Mo,此类元素可能是花岗岩型或接触变质岩型矿的元素组合;4、通过计算方法确定了研究区各元素的背景值和异常下限,圈定了单元素异常,各元素的异常面积和强度都较大。根据元素组合特征,圈定了9个土壤地球化学组合异常,并对其异常评序,结果为Ahs1-Ahs3-Ghs1-Ahs4-Ahs2-Ghs3-Gohs2-Ghs2-Gohs1;最后对各异常进行分类评价,划分出1处甲1类异常,1处乙1类异常,3处乙2类异常,3处乙三类异常,1处丙1类异常;5、根据研究区土壤地球化学异常特征,结合该区域的遥感、地质、物探等相关地质信息,综合分析在区内圈出了5个找矿远景区,远景区主要成矿元素以锌铜金多金属为主;并对远景区分类和评价,5个找矿远景区中划分出1个Ⅰ级成矿远景区,3个Ⅱ级成矿远景区,一个Ⅲ级成矿远景区。
[Abstract]:The Anseba District of Eritrea is located south of the Arab-Nubian Shield, within the Nubian Shield, which is composed of the Neoproterozoic continental margin (870b.c. 670 megabytes) and the young intraoceanic magmatic arc rock mass, Due to the interaction of the East African Rift Valley and the Red Sea Rift, the shield has undergone a long and complicated geological evolution process and has a good metallogenic geological and tectonic background, which is a typical polymetallic metallogenic belt in Ecuador. Due to the influence of the war, the development of the mining industry in our country has been stopped, and the previous geological work in the study area has been little, mainly for remote sensing on a small scale, geophysical exploration and a small number of regional geological surveys. The preliminary data show that the area has metallogenic potential. Based on the project of "Kerkebet gold polymetallic ore exploration in Anseba area, Eritrea", based on the early geological data collected and comprehensive studied, the contents and spatial distribution characteristics of soil elements in the area were found out through soil geochemical investigation. The anomalous lower limit of each element in the soil was determined, and the single element and the comprehensive anomaly were delineated. Combined with 1: 50 000 geological mapping and preliminary land, objects, remote data, the prospecting area is delineated and its prospect is analyzed. The main results and understanding of the study are as follows: 1. The exposed strata in the study area are mainly the Neoproterozoic Harga-Hargaformation and the Nagfa formation, which are the main ore-bearing strata, and the rocks of the group are exposed in the east of the mining area. The fold and fault are more developed, which are favorable to metallogenesis, especially in the intersection of faults, the magmatic rocks exposed in the mining area are mainly basic-acid magmatic rocks, which have great influence on mineralization, and the selective alteration is stronger, and the main erosion becomes silicification. Sericite, kaolin, chlorite, green curtain petrifaction; the main minerals in the district are polymetallic massive sulfides with zinc and copper associated gold, The tectonic hydrothermal type gold deposit and the tectonic altered rock type gold deposit No. 2 are based on the average content of the elements in the rocks of the study area, and the significant enrichment element is the element WGN Ni in the soil. In space, the coefficient of variation of Mo-SbSbSbWAU-Au-BiOAs is greater than 1, the coefficient of variation of strong special-shaped element CuPbPbZN is greater than 0.7 < 1, and the coefficient of variation is special-shaped element .3.The correlation and cluster statistical analysis of soil elements are carried out, and the results show that the variation coefficient is higher than 1, and that the coefficient of variation is greater than 0. 7. The soil element group can be divided into two categories: Au-Bi-Sn-Ag-Sb-Cu-Pb-Zn, which may be an element combination of massive sulphide ore, The other is W-Co-Mo, which may be a combination of elements of granite type or contact metamorphic rock type ore. The background value and anomaly lower limit of each element in the study area are determined by calculation method, and the single element anomaly is delineated. The abnormal area and strength of each element are large. According to the characteristics of elemental assemblages, 9 geochemical assemblages of soil were delineated and their anomalies were evaluated. The results were as follows: Ahs1-Ahs3-Ghs1-Ahs4-Ahs2-Ghs3-Gohs2-Ghs2-Gohs2-Gohs1. Finally, the anomalies were classified and evaluated. According to the characteristics of soil geochemical anomalies in the study area, the relevant geological information such as remote sensing, geology, geophysical exploration, etc., are classified into 1 anomaly, 1 anomaly, 3 anomalies, 3 anomalies, 1 anomaly and 1 anomaly. The paper synthetically analyses five ore prospecting distant areas in the area, the main metallogenic elements of which are mainly zinc, copper and gold polymetals, and the classification and evaluation of the remote areas, the five prospecting prospective areas are divided into 1 grade I metallogenic prospect and 3 鈪，

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