华南钨地球化学块体结构及成因研究  

Research on the Structure and Genesis of Tungsten Geochemical Block in South China

作　　者：刘东盛[1,2] 迟清华[1,2] 陈圆圆 王学求[1,2] 周建[1,2] 刘汉粮[1,2] 张必敏[1,2] 徐善法[1,2] LIU Dongsheng;CHI Qinghua;CHEN Yuanyuan;WANG Xueqiu;ZHOU Jian;LIU Hanliang;ZHANG Bimin;XU Shanfa(MNR Key Laboratory of Geochemical Exploration,Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Science,Langfang 065000,Hebei,China;UNESCO International Centre on Global-scale Geochemistry,Langfang 065000,Hebei,China;Institute of Regional Geological and Mineral Resource Survey of Hebei Province,Langfang 065000,Hebei,China)

机构地区：[1]自然资源部地球化学探测重点实验室,中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000 [2]联合国教科文组织全球尺度地球化学国际研究中心,河北廊坊065000 [3]河北省区域地质调查院,河北廊坊065000

出　　处：《大地构造与成矿学》2019年第5期1010-1022,共13页Geotectonica et Metallogenia

基　　金：国家重点研发计划“穿透性地球化学勘查技术”(2016YFC0600600);国土资源公益性行业科研专项“地球化学走廊带探测试验与示范”(Sino Probe-04-05、201011057)联合资助

摘　　要：华南存在水系沉积物钨含量大于3×10^-6、面积达50余万平方千米的钨地球化学块体。在长达2000余千米的西秦岭造山带.华夏地块地球化学走廊带以区域尺度(1件样品/1~2km)采样方法系统采集了不同时代不同类型的岩浆岩、地层中岩石与沉积物样品,精确测定了包括钨在内的81种元素(指标)的含量,解析了华南钨地球化学块体的内部结构,探讨了块体内钨的分布与富集规律,并对块体的成因进行了研究。根据走廊带沉积物中钨的中高背景区(W=3×10^-6~4×10^-6)、高背景区(W=4×10^-6~6×10^-6)和异常区(W>6×10^-6)分别将华南钨地球化学块体套合结构解析为外围、次级浓集中心和浓集中心,并对各结构主要地质体的钨含量分布进行了研究。揭示了华南钨地球化学块体的形成过程:地壳演化早期的不均一导致钨初步富集在华南造山带的沉积岩中;华南造山带早古生代到晚中生代发生多次陆内造山运动伴随大规模岩浆活动,使古老地层中的钨进一步浓集于加里东期.燕山早期花岗岩;华南晚中生代发生大规模钨成矿作用,钨进一步浓集于矿体及周边。Geochemical block is a large rock mass with high content of a certain chemical element or elements. A huge tungsten geochemical block with an areal extension of 583 000 km2 has been delineated in South China by Chinese geochemists. Study on the internal structure and genesis of this unique tungsten geochemical block may help scientists to understand the differentiation and enrichment of tungsten in South China. In this study, a continuous and high density collection (1 sample was collected every 1 to 2 km) of rocks and corresponding sediments samples was conducted along a South China-West Qinling geochemical profile with a total length of 2000 km, and 81 elements (or analysis parameters) were determined. The study area is divided into 4 sections: the low background section (W<3×10^-6), the middle-high background section (W=3×10.6 to 4×10^-6), the high background section (W=4×10.6 to 6×10^-6), and the anomaly section (W>6×10^-6), on the basis of tungsten distribution. The South China tungsten geochemical block is parsed into 3 parts: periphery, secondary concentration center and concentration center. The first one is the periphery with main determinant of sedimentary rocks in the South China orogenic belt;the second one is secondary concentration center with main determinant of granites;and the third one is concentration center with mineralization as its main determinant. The distribution of tungsten in the three aforementioned determinants was studied carefully. The genesis and evolution of the tungsten geochemical block in South China consist of three processes, which including 1) the inhomogeneity in the early evolution stage of the crust caused the initial tungsten enrichment in the sedimentary rocks of the South China orogenic belt;2) tungsten further enriched in the early Caledonian-Yanshanian granites because of the large-scale magmatism;and 3) large-scale tungsten mineralization in the late Mesozoic in South China, and finally the resultant tungsten enrichment in the ore bodies and surrounding areas.

关 键 词：西秦岭-华南地球化学走廊带 钨地球化学块体 碎屑沉积岩 花岗岩 成矿作用 风化作用 

分 类 号：P595[天文地球—地球化学]