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河北省下平阳-灵山-口头地区地质地球化学特征及找矿方向
Geology and Geochemical Characteristics as Well as Exploration Direction of Xia Pingyang-lingshan-koutou Region of Hebei Province
【作者】 王刚;
【作者基本信息】 吉林大学 , 地质工程(专业学位), 2018, 硕士
【摘要】 研究区位于中朝准地台(Ⅰ2)、山西断隆(Ⅱ23)、五台台拱(Ⅲ29)东南部,太行山构造-岩浆带东部,紧邻紫荆关—灵山深断裂。区内出露地层以早前寒武系变质杂岩及中上元古界、古生界沉积地层为主;中酸性岩浆岩发育,构造复杂,是我省金及多金属矿产的重要找矿区段。区域上矿床的形成主要受地层、构造和岩浆岩的控制。金及多金属矿产成矿地质条件良好。区域上金矿床主要为岩浆热液型矿床和热液石英脉型,成矿有利层位主要出露太古代阜平群中深度变质岩系和中高级混合岩化的变质岩系和中太古代平阳片麻岩,矿化一般分布在燕山期岩体及岩脉与围岩的接触部位,矿化和蚀变的主要类型为硅化、绢云母化、绿泥石化、黄铁矿化。矿体或矿脉多产于构造破碎带内,矿化程度和品位由容矿构造控制。通过对研究区元素丰度特征和分异特征分析,Ag、Au元素浓集系数较高,说明这两个元素有一定的次生富集趋势;其余各元素相对处于贫化状态。变异系数大于1的元素依次是Au、W、As、Sb,说明这些元素在土壤中分布不均匀,有富集的趋势,是成矿的有利地球化学条件。通过对研究区化探数据进行分析处理,确定异常下限,绘制单元素异常图、组合异常图及综合异常图,结合各地质单元地球化学特征,分析表明Au、Ag等成矿元素在各地质单元中与全区的背景值相当或高于背景值,但在岩浆活动剧烈的地方容易富集,表明该区域成矿流体以岩浆热液来源为主。区域金矿床主要受大地构造环境、地层、岩浆岩、构造等多种因素控制,结合研究区地质背景,总结主要的找矿为围绕岩体找矿和围绕脉岩找矿;以地球化学、围岩蚀变、矿化石英脉为主要的矿化标志。通过对综合异常结合地质背景对找矿前景进行了分析,结合本区域的成矿地质条件研究,构造-岩浆-地球化学异常是本区金成矿作用的一个显著特征,岩浆热液活动是系列异常出现的主要因素。在此地区圈定了两个成矿远景区。
【Abstract】 The study area is located in the sino-korean paraplatform(Ⅰ2),shanxi lung(Ⅱ23),five sets of the arch(Ⅲ29)southeast,taihang tectono-magmatic belt to the east,adjacent to zijingguan-lingshan deep fracture.The outcrops in the area are mainly early Cambrian metamorphic complex,middle and upper proterozoic and Paleozoic sedimentary strata.The medium-acidic magmatic rocks are developed with complex structure and are important prospecting sections for gold and polymetallic minerals in our province.The formation of regional deposits is mainly controlled by strata,tectonics and magmatic rocks.The metallogenic geological conditions of gold and polymetallic minerals are good.Region type gold deposits are mainly magmatic hydrothermal deposits and hydrothermal quartz vein type,main exposed mineralization favorable horizon archean fuping group in the deep metamorphic rock series and senior migmatization metamorphic rock series and the archean pingyang gneiss,mineralization distribution in the rock mass in yanshan period and the contact part of the dike and surrounding rock,the main types of pyrite mineralization and alteration.The ore body or vein usually occurs in the tectonic fracture zone.By analyzing the abundance and differentiation characteristics of soil elements in the study area,Ag and Au elements had higher concentration coefficient,indicating that these two elements had a certain tendency of secondary enrichment.The remaining elements are relatively depleted.The elements with a coefficient of variation greater than 1 are Au,W,As and Sb,respectively,indicating that these elements are distributed unevenly in the soil and tend to be enriched,which are favorable geochemical conditions for mineralization.Through the analysis of geochemical data in the study area,to determine the threshold,draw relevant datum,analyzing the geochemical features of geological unit,analysis shows that the Au,Ag and other ore-forming elements in different geological unit and the background of the whole value equal or higher than the background value,but easy to enrichment in intense magmatic activity,show that the regional ore-forming fluid is given priority to with magmatic hydrothermal origin.Regional gold deposits are mainly controlled by geotectonic environment,stratum,magmatite,tectonics and other factors.Combined with the geological background of the study area,the main prospecting areas are summarized as surrounding rock mass and surrounding vein rock.The main signs of mineralization are geochemistry,wall rock alteration and mineral fossils.The prospect of ore prospecting is analyzed through the combination of comprehensive anomalies and geological background.Combined with the study of the metallogenic geological conditions in this region,the tectonic-magma-geochemical anomalies are a significant feature of gold mineralization in this region,and magmatic hydrothermal activity is the main factor for the occurrence of series anomalies.Two mineralization prospects were delineated in this area.