The suitability of floodplain sediment as a global sampling medium: Evidence from China

Research undertaken by IGCP 259 (International Geochemical Mapping) indicates that wide-spaced sampling is a fundamental concept of international geochemical mapping as it appears to provide the only practical way to obtain a relative rapid (10-20 years) overview of global geochemistry. The main aim of this study is to test the suitability of floodplain sediment as a global sampling medium. Thirteen floodplain sediment samples and 13 stream sediment samples were taken at the exit of 13 super large drainage basins (SCB). The areal extents of these basins are in the order of 1000-10,000 km(2) Within each SCB, 3-11 stream sediment samples each representing a component catchment basin (CCB) of 100-1000 km(2) were also taken. Fourty nine elements were analyzed. The results were compared with the average values derived from calculating thousands of stream sediment data available from China's National Geochemical Mapping (RGNG) program. Strong similiarities were demonstrated in distribution and trends among the three levels of data. The set of floodplain sediment data shows great coincidence with RGNR stream sediment data.