摘要:
为削弱拉脊山东段地区化探数据(典型的成分数据)存在的闭合效应,进一步分析该区地球化学元素空间组合分布规律,使用等距对数比变换(ilr)"打开"水系沉积物地球化学数据;采用稳健主成分分析(RPCA)构建组合模型,用于识别组合地球化学异常;通过S-A分形滤波技术强化弱异常并分离异常与背景,圈定地球化学致矿异常,进一步指导矿产勘查.研究结果表明:得到两组与矿化相关的元素组合,第一组为Au-As,与研究区的构造蚀变岩型金(砷)矿(金源东沟等)相关;第二组为Cu-Ni,与区域内铜镍硫化物矿床(拉水峡等)相关.S-A滤波技术可以进一步分解组合异常,强化弱小异常,同时能够缩小强背景下的异常面积,结合研究区地质概况和分解后的异常图可以进一步指导该地区构造蚀变岩型Au(As)矿和铜镍硫化物矿床的找矿勘查工作.
Abstract:
In order to weaken the closure effect of the geochemical data which serve as typical component data,the authors analyzed the spatial distribution of geochemical elements in the Laji Mountains.The authors used the isometric log-ratio(ilr) transformation to "open" the geochemical data of the water sediments,built the combined model using robust principal component analysis (RPCA) to identify the combined geochemical anomalies and employed fractal filtering technique to strengthen weak anomalies and separate anomaly from background.In this way,the authors delineated geochemical anomaly so as to guide mineral exploration better.The result obtained by using RPCA displays two different compositional assemblages: (I) Au-As,probably representing tectonic-altered rock type gold deposit like the east ditch of Jinyuan,and (II) Cu-Ni,likely representing copper-nickel sulfide mineralization such as Lashuixia.The results from S-A filter technique can decompose anomalies further,strengthen weak anomaly and reduce the abnormal area in the strong background and,in combination with the geological survey of the study area and the anomaly map,can better search for tectonic-altered rock type Au-As deposits and Cu-Ni sulfide mineralization.
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