Cu- and Zn-Soil Anomalies in the NE Border of the South Portuguese Zone (Iberian Variscides, Portugal) Identified by Multifractal and Geostatistical Analyses
Cu- and Zn-Soil Anomalies in the NE Border of the South Portuguese Zone (Iberian Variscides, Portugal) Identified by Multifractal and Geostatistical Analyses
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DOI：
10.1007/s11053-013-9217-5
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发表时间：
2014-06
影响因子：
5.4
通讯作者：
F. Luz;António Mateus;João Xavier Matos;Mário A. Gonçalves
中科院分区：
文献类型：
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作者：
F. Luz;António Mateus;João Xavier Matos;Mário A. Gonçalves
Albernoa/Entradas-S.多明戈斯地区（东北边界的伊比利亚硫铁矿带，南葡萄牙区）进行了检查，以分离异常的背景，使用浓度-面积分形模型。土壤中Cu和Zn含量的分布格局主要受基岩的影响。变沉积岩序列上土壤Cu和Zn含量的区域阈值分别为20-25和20-60 ppm，当存在变火山岩时，分别变为30-50和20-90 ppm。一阶阈值为铜80-90 ppm的土壤中的沉积物和70-80 ppm的土壤中的序列轴承变质火山岩。对于锌，一阶阈值为40-80和90-100 ppm的土壤上的沉积物和变质火山岩，分别。土壤中的铜和锌土壤值分别高于100和300 ppm，概述了含有大量硫化物分布的变质沉积物和变质火山岩。根据这些结果，Alvares和Albernoa/Entradas地区成为第一优先勘探目标。研究区土壤Cu、Zn异常的非重合性反映了风化过程中元素分散的差异性，主要反映了不同岩石类型的原始成分或华力西变形/重结晶过程中的化学变化所导致的不同金属来源，所建立的区域基线数据可为环境研究提供参考。
Extensive Cu- and Zn-soil geochemical data in the Albernoa/Entradas–S. Domingos region (NE border of the Iberian Pyrite Belt, South Portuguese Zone) were examined to separate anomalies from background using the concentration–area fractal model. Distribution patterns of Cu and Zn concentrations in soil are primarily influenced by bedrock. The regional threshold values of Cu- and Zn-soil contents over metasedimentary sequences are 20–25 and 20–60 ppm, respectively, becoming 30–50 and 20–90 ppm, respectively, when metavolcanic rocks are present. The first-order threshold values for Cu are 80–90 ppm in soils over metasediments and 70–80 ppm in soils over sequences bearing metavolcanics. For Zn, the first-order threshold values are 40–80 and 90–100 ppm in soils over metasediments and metavolcanic rocks, respectively. Metasediments and metavolcanics comprising significant sulphide disseminations are outlined by Cu- and Zn-soil values above 100 and 300 ppm in soil, respectively. On the basis of these results, Alvares and Albernoa/Entradas areas emerge as the first priority targets for exploration. The observed non-coincidence of Cu- and Zn-soil anomalies in soil in the area could reflect difference in element dispersion during weathering, they mostly indicate distinct metal sources related to the original composition of different rock types or to chemical changes developed during Variscan deformation/re-crystallization path. The established regional baseline data can be used as reference for environmental studies.