ELEMENT CONCENTRATIONS IN RIVER DELTA SEDIMENTS AND MINERAL RESOURCES POTENTIAL IN THE DRAINAGE BASIN: A CASE STUDY IN THE XIANGJIANG, ZISHUI, YUANJIANG, AND LISHUI RIVERS BASINS
河口三角洲元素含量与矿产资源——以湘资沅澧为例

Widely-spaced global geochemical mapping has attracted international interests since the 1990s'. In 1998 the author conducted geochemical soil survey in the Dongting Lake alluvium plain and found that the average concentration of delta sediments at the mouths of the Xiangjiang, Zishui, Yuanjiang, and Lishui rivers draining to the Dongting Lake bears close relation with the mineral resources potential within the drainage basin. An attempt was also made to use the average anomalous contents of ore elements in the Dongting Lake alluvium plain to predict the mineral resources potential in the upstream Changjiang River basin (approx. 1 million km2). The discoveries of large Sn deposits in the Xiangjiang River basin in recent years have verified the feasibility of this approach and analysis of delta sediments samples to predict the mineral resources potential within large drainage basins (10 000 to million km2 in dimension). This will provide strong evidences in supporting the feasibility of the global geochemical mapping project along major rivers in the world.