中国南部湿润半湿润丘陵山区不同粒级水系沉积物地球化学特征对比研究  

Geochemical Characteristics Comparison of Different Scale Sediments in the Humid and Semi-humid Hilly Area,Southern China

作　　者：陈富荣[1] 史春鸿[1] 梁红霞[1] 

机构地区：[1]安徽省地质调查院,安徽合肥230001

出　　处：《岩矿测试》2017年第2期136-145,共10页Rock and Mineral Analysis

基　　金：中国地质调查局地质调查项目(1212011120938;1212011220592)

摘　　要：不同景观条件下选取合适的采样粒级是准确地获取地球化学信息,提升地质找矿效果的关键。为研究中国南部湿润半湿润中低山丘陵景观区水系沉积物测量最佳采样粒级,本文在安徽省南部胡乐司—宁国墩地区开展了区域化探采样粒度方法技术试验,采集-60目和-10目^+80目两种粒级样品,采用波长色散X射线荧光光谱法和电感耦合等离子体质谱法为主体的配套分析方案和测试技术获取了全国区域化探扫面规定的40种元素高精度数据。研究表明:两种粒级水系沉积物中造岩元素背景含量与区域岩石背景值基本接近,其他微量元素多呈富集状态,以-10^+80目粒级中As、Au、Hg、Mo、Pb、Sb等成矿元素富集程度最强;-10^+80目粒级受后期表生改造作用影响较弱,最大限度保留了原生地球化学分布特征,并在准确圈定与矿化有关的异常和清晰反映矿致异常特征等方面明显优于-60目粒级。因此,建议在安徽省南部中低山丘陵景观区,选择-10^+80目粒级为水系沉积物测量的最佳采样粒级,研究结果可以为中国相似景观区地球化学勘查找矿水系沉积物测量采样粒级的选择提供参考。Appropriate sampling grain size is very important for accurate geochemical information and better exploration effects in different landscapes. In order to determine the best sampling grain size of the sediments in the humid and semi-humid hilly landscape, a sampling experiment was carried out. Samples of two scales, - 60 and -10 - ＋80,were collected from the Hulesi-Ningguodun area in Southern Anhui Province. 40-element high- precision data, which are needed for regional geochemical exploration, were acquired by X-ray Fluorescence Spectrometry （ XRF） and Inductively Coupled Plasma-Mass Spectrometry （ ICP-MS ） . Results show that the contents of rock-forming elements in sediments are similar to the background values of regional rocks. Samples with grain size of -10 - ＋ 80 scale are rich in As, Au, Hg, Mo, Pb and Sb. Samples with grain size of - 10 - ＋80 scale have been weakly modified by later surface weathering and reserve the original geochemical characteristics, which are remarkably better than the - 60 scale in delineating anomalies of mineralization and reflecting characteristics of ore-related anomalies. Therefore, the -10 - ＋ 80 scale is preferred for stream sediment surveys in the middle and lower mountains and hilly areas in southern Anhui province, which is meaningful to the choice of stream sediment sample grain size in performing geochemical exploration of similar landscapes in China.

关 键 词：采样粒级 水系沉积物 造岩元素 地球化学特征 湿润半湿润景观区 

分 类 号：P622.3[天文地球—地质矿产勘探] O657.31[天文地球—地质学]