A national survey project to map out geographic distributions of chemicals passed the verification check on May 23, 2005. Initiated by China Geological Survey, and jointly implemented by 28 provinces, municipalities, and autonomous regions, the project has produced unprecedented findings in terms of areas surveyed, data collected, accuracy, analysis, and mapping efforts. The survey led to the establishment of a platform to share basic geological services in multiple fields, marking a historical leap from research findings to social applications.
The survey, covering an area of 6.5 million square kilometers in 28 provinces, municipalities, and autonomous regions, analyzed 1.42 million geochemical samples, tested 39 elements using sophisticated large instruments, and obtained 55.4 million original data. The systematic collection of these data has resulted in a national database for geochemical mapping. A nationwide geochemical atlas is compiled to reflect 39 chemical elements under diverse geological backgrounds and their geochemical properties. By revealing geochemical distributions of China?痵 water-born sediment elements and presenting geochemical backgrounds of surface elements, the findings constitute important evidences for basic geological studies. The survey has spotted more than 50,000 abnormal sites, from which some 2900 were found with minerals, and more than 700 mines with gold, silver, copper, lead, zinc, tin, tungsten, and molybdenum. Of them, some 70 mines are rated at large or medium scale. Findings also revealed the distribution of environment related elements, including beneficial nitrogen, phosphor, potassium, boron, manganese, and hazardous cadmium, mercury, lead and arsenic, which is valuable for agriculture, urbanization, environmental protection and local diseases researches. The survey expanded applications of geochemistry, and demonstrated the distribution of major mineral resources in the country.
Meanwhile, Chinese researchers have developed key geochemical mapping techniques for special geological sites, including arid desert land, Karst areas, cold lake and forest swamps. The survey team also worked out methods and technical modalities to test 39 chemical elements at the trace level, greatly enhanced the sensitivity, accuracy, and correctness of sample analyzing. Researchers integrated diverse techniques for geochemical mapping, including database technology and mapping techniques. The survey and associated studies have enriched the theory of geochemical mapping. |
