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| Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area, Shandong Province, China | |
| 基金项目： | 中国科学院资助项目;甘肃省自然科学基金 |
| 摘 要： | springerlink.com Studies of mantle fluids are currently one of the hot topics in the earth science, greatly contributing to re-vealing origins and evolutions of fluids. In general, the concept of mantle fluids refers to their active compo-nents, such as CO2, H2O, N2, etc., while the noble gases inert in chemical properties belong to another research system. Due to their marked differences in various fluid sources of the Earth1], the isotopic sig-natures of He and Ar have been widely used a… |
| 收稿时间： | 3 August 2004 |
| 修稿时间： | 7 May 2005 |
Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area,Shandong Province, China |
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| Authors: | MA Jinlong TAO Mingxin YE Xianren |
| Institution: | 1. Resources and Environmental School, Lanzhou University, Lanzhou 730000, China;Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China 2. Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China;College of Resources Science & Technology, Beijing Normal University, Beijing 100875, China 3. Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China |
| Abstract: | Fluids and noble gases of mantle-derived materials are important tracers for the mantle information. Compositions of primary fluids and noble gases in mantle-derived minerals from the Yishu area, Shandong Province, China, were tested by the methods of heat-bursting and heat-melting respectively. The fluids are mainly composed of CO2, CO and H2, which account for about 90% of the total, and are similar to the mantle-derived rocks from other areas of eastern China; ratios of 3He/4He in almost all samples range from 0.82 Ra to 2.74 Ra, whereas 40Ar/36Ar from 299.5 to 758.8. Both ranges are much lower than those of the typical ocean mantle-derived samples (such as MORB) and primarily reflect the influences of the atmospheric components and the radiogenic isotopes. Ratios of C/3He range from 27.6×109 to 1050×109, N2/Ar from 927 to 56612, and N2/3He from 2.5×109 to 27×109, similar to those in western United States and New Zealand which belong to the tectonic plate collision regions. The ratios fall in the intersect of mantle-crust-atmosphere in the comprehensive tracer-charts, reflecting the influences of the atmosphere and the crusts with organic components. Our results suggest that the composition of the primary fluids and the isotopic ratios of the noble gases may either reflect the evolution process of mantle-derived rocks connected with the rise and eruption of magma, or the influence of the ancient subduction-plate on the continental mantle of this region. |
| Keywords: | noble gases primary fluids mantle-derived minerals Yishu area |
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