全球尺度地球化学填图计划对比研究

A comparison of global-scale geochemical mapping projects

文中简述了全球尺度地球化学填图发展的历史,以近20年在中国、欧洲、美洲和澳大利亚开展的6项全球尺度地球化学填图计划为例,结合"国际地球化学填图计划"和"全球地球化学基准计划"的相关建议和要求,从样品采集和样品分析两个角度展开评价和对比,并初步总结了全球尺度地球化学填图在采样和分析两个方面存在的问题。6个填图计划中,仅欧洲的FOREGS计划采用多介质采样方案,中国的全国地球化学基准计划(CGB)按照不同的地貌特征采集不同的代表性的汇水域沉积物样品,其他4个计划采用单一介质的采样方案,采集土壤或泛滥平原/河漫滩沉积物。中国的分析水平总体处于国际领先水平,能分析的元素最多(78个),元素分析检出限全部低于地壳克拉克值,标准物质能监控所有分析的元素。

The spatial distributions and changes of elements in the earth have been studied by global-scale geochemical mapping, providing basic datasets and maps for the sustainable development of resources and environment. This paper briefly describes the history of global-scale geochemical mapping, and gives an evaluation and comparison for the sampling and analytical programs of the six global-scale mapping projects conducted in the past 20 years in China, Europe, North America and Australia. Among these mapping projects only European FORGES project collected multi-media samples （soils, stream sediments, floodplain sediments, humus, stream water）; the China Geochemical Baselines project collected samples from different geomorphic landscapes （soils in agricultural plain land, floodplain/overbank sediments in mountainous terrains, catchment sediments in desert terrains）; and the other four projects （Australia NGSA, USA NASGLP, Chinese EGMON, European GEMAS） using uni-media sampling program, collected soil or floodplain/catchment sediments. The analytical methodology in China reaches international leading level： 78 elements can be determined; their detection limits meet the requirements for global-scale geochemical mapping; and the analytical quality is controlled by standard reference materials.