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您的检索式：作者名="PENGJiantang"
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| 1 | Scheelite Sm-Nd dating and quartz Ar-Ar dating for Woxi Au-Sb-W deposit,western Hunan显示文摘Scheelite Sm-Nd and quartz Ar-Ar dating were accomplished for the Woxi Au-Sb-W deposit in western hu-nan. The results show that the Sm and Nd concentrations of scheelite are relatively high, and Sm/Nd ratios are usually high and variable. In the 147Sm/144Nd vs. 143Nd/144Nd diagram, the disseminated scheelites show a good linear array, which corresponds to an isochron age of 402 6 Ma and an initial 143Nd/144Nd ratio of 0.510544 9 (2s ) with a e Nd(t) value of -30.7. The Ar-Ar age spectra for 2 quartz samples display the saddle shape. The minimum apparent age, plateau age and isochron age of each quartz sample generally overlap within errors; and both the minimum apparent ages of 420 20 and 414 19 Ma coincide well with the scheelite Sm-Nd age. Both Sm-Nd and Ar-Ar dating results reveal that the Au-Sb-W mineralization at Woxi district took place in the Late Caledonian. This is in good agreement with the tectonic evolution of the Xuefengshan district and with some geo-chronological data available for Au, Sb and W deposits in this area. The low initial Nd isotope ratio of scheelites sug-gests that the fluid responsible for Au-Sb-W mineralization at the Woxi is of deep crustal origin and probably originated from the underlying Archaean continental basement rather than the host Proterozoic strata in western Hunan. The con-straints on the mineralization time and on the fluid source provide insight into the genesis of the Woxi deposit. | PENGJiantang HURuizhong ZHAOJunhong FUYazhou LINYuanxian | 2003 | Chinese Science Bulletin2003，48，23： | 37 |
| 2 | Geochemical characteristics of seamount ferromanganese nodules from mid-Pacific Ocean显示文摘Nine seamount ferromanganese nodules from six seamounts in the mid-Paciflc Ocean have been sampled,the obtained sixteen sub-samples were used to analyze their main elements, trace elements and rare earth elements by the chemical method and ICP-MS, platinum group elements have also been analyzed for some subsamples, using the methods of Te co-precipitation pre-concentration and isotope dilution. All subsamples have been analyzed by X-ray diffraction for their mineral composition. It is shown from the analysis results that the mineral composition, chemical characteristics and the occurrence of main components of seamount nodules from mid-Pacific Ocean are similar to those of hydrogenous cobalt-rich crust on seamounts, which indicates that seamount nodules were hydrogenous. Compared with the ferromanganese nodules occurring on the surface of deep-sea sediments, seamount nodules have higher Fe and Co but lower Cu and Ni, so the seamount nodules from mid-Pacific Ocean might be formed on the surface of sediments on seamounts in weak acidic but strong oxidation environment. Because of their similar occurring depth and redox conditions, seamount nodules are very similar to cobait-rich crust in their chemical composition, minerals and occurrence of main compositions. However, having been found on the sediment-seawater interface, seamount nodules experienced the influence of early-diagenesis of sediments, so the typical seamount crust has some characteristics of transition to ferromanganese nodules. | BUWenrui SHIXuefa PENGJiantang QILiang | 2003 | Chinese Science Bulletin2003，48，B06： | 1 |
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