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- Du, Andao, et al.
(författare)
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Preparation and certification of Re-Os dating reference materials: Molybdenites HLP and JDC
- 2004
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Ingår i: Geostandards and Geoanalytical Research. - 1639-4488 .- 1751-908X. ; 28:1, s. 41-52
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Tidskriftsartikel (refereegranskat)abstract
- Two Re-Os dating reference material molybdenites were prepared. Molybdenite JDC and molybdenite HLP are from a carbonate vein-type molybdenum-(lead)-uranium deposit in the Jinduicheng-Huanglongpu area of Shaanxi province, China. The samples proved to be homogeneous, based on the coefficient of variation of analytical results and an analysis of variance test. The sampling weight was 0.1 g for JDC and 0.025 g for HLP. An isotope dilution method was used for the determination of Re and Os. Sample decomposition and pre- concentration of Re and Os prior to measurement were accomplished using a variety of methods: acid digestion, alkali fusion, ion exchange and solvent extraction. Negative thermal ionisation mass spectrometry and inductively coupled plasma-mass spectrometry were used for the determination of Re and 187Os concentration and isotope ratios. The certified values include the contents of Re and Os and the model ages. For HLP, the Re content was 283.8 ± 6.2 µg g-1, 187Os was 659 ± 14 ng g-1 and the Re-Os model age was 221.4 ± 5.6 Ma. For JDC, the Re content was 17.39 ± 0.32 µg g-1, 187Os was 25.46 ± 0.60 ng g-1 and the Re-Os model age was 139.6 ± 3.8 Ma. Uncertainties for both certified reference materials are stated at the 95% level of confidence. Three laboratories (from three countries: P.R. China, USA, Sweden) joined in the certification programme. These certified reference materials are primarily useful for Re-Os dating of molybdenite, sulfides, black shale, etc. .
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| 2. |
- Wan, Bo, et al.
(författare)
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Re-Os molybdenite age of the Cu-Mo skarn ore deposit at Suoerkuduke in East Junggar, NW China and its geological significance
- 2014
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Ingår i: Ore Geology Reviews. - : Elsevier BV. - 0169-1368 .- 1872-7360. ; 56, s. 541-548
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Forskningsöversikt (refereegranskat)abstract
- The Suoerkuduke Cu-Mo ore is a medium-sized skarn deposit in the East Junggar orogen of the southern Altaids, Xinjiang, Northwest China. We measured Re-Os isotopes of a molybdenite veinlet from the main ore body, of which eight yielded model ages ranging from 303 +/- 5 to 317 +/- 5 Ma with a well-constrained Re-187-Os-187 isochron age of 305 +/- 7 Ma, a MSWD of 4.9 and a weighted average model age of 310 +/- 4 Ma with a MSWD of 4.2. The Re-187-Os-187 isochron age is consistent with the weighted mean model age, within error, and indicates that the time of Cu-Mo mineralization was at c. 310 Ma in the late Carboniferous. This new age is close to the youngest porphyry-related Cu-Mo metallogenic epoch (c. 311 Ma) in the East Junggar region, and is not, as previously suggested, in the Permian. Considering the implications of this new age, we propose that the Suoerkuduke deposit was part of a large-scale porphyry-skarn system, which formed by the interaction between far-traveled hydrothermal fluids and the calcium-rich volcanic wall rocks.
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