The Comparative Study On The Content And Metallogenic Signifance Of Gold, Molybdenum, Tungsten And Tin In Mantle Rocks From Eastem China

Gold, molybdenum, tungsten and tin content of the Cenozoic mantle-derived xenoliths and their host rocks from the North China platform (Hannuoba of Hebei province, Linqu, Changle, Jiaozhou (Mesozoic) of Shandong Province and Nushan, Mingguang of Anhui Province) and the South China block (Liuhe of Jiangsu Province, Xilong of Zhejiang Province, Niutoushan of Fujian Province, Ying fengling of Guangdong Province, Ding'an and Penglai of Hainan Province) in eastem China was systematically analyzed. And these systematically essential data were first accumulated.On the basis of systematic analysis and comparative research on the distribution of gold, molybdenum, tungsten and tin content, combining the foundamental features of metallogenic mega-provinces in eastem China and the geochemical properties of gold, molybdenum, tungsten and tin, some conclusions can be drawn as follows: 1. (1) The gold content of mantle-derived xenoliths are usually higher than that of their host rocks.(2) The distribution of gold content is inhomogeneous spatially. The high gold content of the mantle rocks on the two margins (Hannuoba of Hebei Province and Linqu, Changle of Shandong Province) of the North China platform is corresponding to the gold deposits-concentrated districts in northwest Hebei Province and Shandong Province. The gold content of mantle rocks, especially the gold content of mantle-derived xenoliths may be an indicator to the distribution of gold deposits-concentrated districts.(3) The gold-rich lithospheric mantle may be the material source of later activation, transportation, enrichment and mineralization of the gold by auriferous CO₂ mantle fluids.(4) Sulfides inclusions of mantle-derived xenoliths from different districts have different gold content. The distribution tendency of gold content in sulfide inclusions of mantle-derived xenoliths is similar to that in mantle-derived xenoliths. Gold content in sulfide inclusions of mantle-derived xenoliths is far higher than gold content in mantle-derived xenoliths, showing that gold in mantle-derived xenoliths is concentrated mostly on sulfides or associated with sulfides.(5) Gold content is high not only in mantle-derived xenoliths but also in sulfide inclusions of mantle-derived xenoliths from Ding'an and Penglai, Hainan Province, suggesting that some blocks of the lithospheric mantle in Hainan Province might be derived from ancient gold-rich lithospheric mantle of western Australia, and that Hainan Province may possibly be an important gold deposits-concentrated district.2. (1) Unlike gold, molybdenum content of host rocks is remarkably higher than that of mantle-derived xenoliths.(2) The molybdenum content of mantle-derived xenoliths and their host rocks is found to have higher values on the two margins (Hannuoba of Hebei Province and Linqu, Changle of ShandongProvince and Nushan, Mingguang of Anhui province) of the North China platform than on South China block in SE China, corresponding to the fact that the large-scale molybdenum deposits are concentrated in the two margins of the North China platform. The molybdenum content of the mantle rocks, especially the molybdenum content of the host basalts may be an indicator to the distribution of molybdenum deposits-concentrated districts.3. (1) Tungsten content of host basalts is usually higher than that of their mantle-derived xenoliths.(2) The tungsten content of host basalts in the North China block (Hannuoba of Hebei Province, Linqu, Changle, Jiaozhou (Mesozoic) of Shandong Province and Nushan, Mingguang of Anhui Province) is higher than that in the South China block (Niutoushan of Fujian Province, Ding'an and Penglai of Hainan Province), while the tungsten content of mantle-derived xenoliths in the North China block is lower than that in the South China block (Niutoushan of Fujian Province, Ying fengling of Guangdong Province, Ding'an and Penglai of Hainan Province). That is to say, the distribution tendency of tungsten content of mantle-derived xenoliths is contrary to that of host basalts, showing that the primitive distribution of tungsten in mantle may be homogeneous spatially, and the formation and distribution of tungsten deposits and tungsten ore concentrated districts in China may be the products of the crust evolution.4. (1) Tin content of host basalts is also usually higher than that of their mantle-derived xenoliths. (2) Compared with molybdenum and tungsten, the distribution of tin content of host basaltsand mantle-derived xenoliths among different locations is more homogeneous, and there is no clear distribution tendency of tin content. Tin deposit-concentrated districts are in the south and southwest China. Compared with tungsten, the formation of the tin deposit-concentrated districts in China may be need more and farther crust evolution.5. Difference of the content of gold, molybdenum, tungsten and tin between in mantle-derived xenoliths and in host basalts, difference of the content of gold, molybdenum, tungsten and tin in mantle-derived xenoliths and host basalts among different locations and difference of the distribution of gold, molybdenum, tungsten and tin deposit-concentrated districts in China is related to the material source of lithospheric mantle, the crust evolution and the geochemical properties of gold, molybdenum, tungsten and tin.