Global geochemical mapping and its implementation in the Asia-Pacific region

"IGCP" Projects 259 (International Geochemical Mapping) and 360 (Global Geo chemical Baseline) under the aegis of UNESCO's International Geochemical Co rrelation Program made recommendations for standardizing geochemical mappin g protocols and for conducting a wide-spaced sampling of the Earth's land s urface based on a Global Reference Network of approximately 5000 160 x 160 km cells. A pilot study has been conducted throughout China during which th ese recommendations were implemented. During the pilot study, 500 floodplai n samples representing drainage basins ranging in area from 1000 to 6000 km (2) were collected throughout China and analyzed. The widely spaced samplin g used for the pilot study was compared to the very dense sampling (x milli on samplings of sediment for all of China) used for China's Regional Geoche mical National Reconnaissance Program. The geochemical maps generated from the wide-spaced sampling are strikingly similar to those generated from dat a based on the detailed sampling. Such low density floodplain sampling pres ents a relatively low-cost way to get a quick overview of the geochemistry of a large area of the Earth's surface. The implementation of this project in the Asia-Pacific region and the problems encountered are discussed in th e present paper. (C) 2001 Elsevier Science Ltd. All rights reserved.