【作者】 岳可芬；

【导师】 赫英；

【作者基本信息】 西北大学 ， 地球化学， 2006， 博士

【摘要】 本文对中国东部华北地台及以南新生代地幔岩包体及其寄主玄武岩中金、钼、钨、锡含量进行了较系统的分析,首次得到较系统的基础数据。通过对中国东部华北地台及以南新生代地幔岩包体及其寄主玄武岩中金、钼、钨、锡含量分布的比较研究,结合中国东部成矿域的特征以及金、钼、钨、锡的地球化学性质,取得了以下新的认识和进展: 1.(1)金在地幔岩包体中的含量通常高于寄主玄武岩中的含量。 (2)不同地区地幔岩中金含量分布是不均一的。华北地台两缘(河北汉诺坝和山东临朐、昌乐)地幔岩有高的金含量分布,与我国地壳金矿多分布在华北地台两缘相对应。地幔岩特别是地幔岩包体中金含量的高低,对地壳中金矿床和金矿集中区的分布有指示意义。 (3)地幔岩包体金含量的高低主要是由上地幔金的物质基础所决定,地幔交代、减薄、去气等起使金活化、运移的作用。 (4)地幔岩包体金含量高的地区,地幔岩包体中硫化物包裹体金含量也高。而且金在硫化物包裹体中含量远高于地幔岩包体全岩。说明金主要以硫化物或与硫化物共存的形式存在于地幔中。 (5)海南岛定安和蓬莱地幔岩包体有高的金含量,地幔岩包体中硫化物包裹体也有高的金含量,推测海南岛有可能是重要的金矿集中区。 2.(1)与金不同,钼在寄主玄武岩中的含量显著高于在地幔岩包体中的含量。 (2)中国东部华北地块和华南地块寄主玄武岩中的钼含量在空间分布上明显表现为华北地块两缘高而华南地块低,地幔岩包体也有相似的趋势,只是没有寄主玄武岩显著。结合我国大型钼矿集中于华北克拉通两缘(比金偏外)的事实,寄主玄武岩中钼含量的高低,与地壳中钼矿床和钼矿集中区的分布有对应关系。地幔岩特别是玄武岩中钼含量的高低,对地壳中钼矿床和钼矿集中区的分布有指示意义。更多还原

【Abstract】 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.更多还原