China geochemical baselines: Sampling methodology

摘要: Abstract The China Geochemical Baselines Project (CGB) was launched in 2008, and sampling completed 2012. Its purpose is to document the abundance spatial distribution of chemical elements covering all China. database accompanying element maps represent a geochemical baseline against which future human-induced or natural changes can be quantified. methodology updated developed for China's diverse landscape terrains mountains, hills, plains, desert, grassland, loess karst order obtain nationwide high-resolution harmonious data. Floodplain sediment alluvial soil used as sample medium plain hilly exorheic river systems eastern Overbank adopted mountainous south-western Methods collecting catchment basin lake sediments were desert semi-desert terrains, respectively, endorheic drainage northern north-western Two sites allocated each CGB grid cell 1° (long.) × 40′ (lat.), approximately equal 80 × 80 km size. At site, two samples taken; one from depth 0–25 cm second, deeper greater than 100 cm deepest part horizon C possible we take. A total 6617 3382 have been collected at 1500 cells across whole (9.6 million km 2 ), corresponding density site per 3000 km . In addition, 11,943 rock also aid interpretation geogenic sources elements. Before analysis, sieved 2 + , organic C, CO H O + pH determined under strict laboratory analytical quality control. An Internet-based software named Digital Earth managing maps. Initial results show excellent correlations with lithology, mineral resources mining activities, industry urban agriculture, climate.