| 海底多金属结核和富钴结壳的He同位素对比研究 |
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| 关键词:polymetallic nodules cobalt crust helium isotope interplanetary dust particles (IDPs) |
| 基金项目:国土资源部同位素地质研究开放实验室资助，国家自然科学基金(编号:49873002) |
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| A Comparative Study of Helium Isotope of Polymetallic Nodules and Cobalt Crust |
| A comparative study of helium isotope for polymetallic nodules from C-C zone of the east Pacific basin and cobalt crusts from Marshall Island was reported. The nodules from C-C zone of the east Pacific basin all have extraordinarily high 3He/ 4He ratios, from 1.7×10 -5 to 13.3×10 -5 . The 3He/ 4He ratios of all nodule samples are higher than the MORB average level, some even higher than the hot point level. The 3He/ 4He ratios and 4He concentrations of magnetic fractions are obviously higher than those of bulk. The 3He/ 4He ratios of cobalt crust are lower than those of nodules, and vary in a wide range, from 6.05×10 -8 to 8.08×10 -5 . In the 3He- 4He figure, most data points of cobalt crust fall into the helium isotope range of MORB and mantle plume. The micrometeorite interplanetary dust particles (IDPs) smaller than 10μm in diameter have extraordinarily high 3He/ 4He ratios and abundant helium. Trace of IDPs can result in extraordinarily high 3He/ 4He ratios in terrestrial material. In the 3He- 3He/ 4He figure, all data points of nodules, cobalt crusts and sediments sit in or close to the mixing curve between the micrometeorite interplanetary dust particles (IDPs) and the terrigenous sediments. It is considered that, just as those of pelagic sediments,the anomalous helium isotope ratios of nodules and crust can be attributed to IDPs. The concentration of IDPs in nodules is about 1×10 -6 ,and that in cobalt crust is lower, from 80×10 -9 to 800 ×10 -9. |
| LI Yan-he,LI Jin-cheng,SONG He-bin.1999.A Comparative Study of Helium Isotope of Polymetallic Nodules and Cobalt Crust[J].Acta Geoscientica Sinica,20(4):378-384. |
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