دورية أكاديمية
Rhenium-osmium isotope and platinum-group elements in the Xinjie layered intrusion, SW China: Implications for source mantle composition, mantle evolution, PGE fractionation and mineralization
| العنوان: | Rhenium-osmium isotope and platinum-group elements in the Xinjie layered intrusion, SW China: Implications for source mantle composition, mantle evolution, PGE fractionation and mineralization |
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| المؤلفون: | Liu, BG, Chu, ZY, Gou, TZ, Zhong, H, Qi, L, Hu, RZ, Zhou, MF, Zhu, WG |
| بيانات النشر: | //www.elsevier.com/locate/gca United Kingdom |
| سنة النشر: | 2011 |
| المجموعة: | University of Hong Kong: HKU Scholars Hub |
| مصطلحات موضوعية: | Emplacement, Dissolution, Fractionation, Isotopic analysis, Igneous intrusion |
| الوصف: | The Xinjie mafic-ultramafic layered intrusion in the Emeishan large igneous province (ELIP) hosts Cu-Ni-platinum group element (PGE) sulfide ore layers within the lower part and Fe-Ti-V oxide-bearing horizons within the middle part. The major magmatic Cu-Ni-PGE sulfide ores and spatially associated cumulate rocks are examined for their PGE contents and Re-Os isotopic systematics. The samples yielded a Re-Os isochron with an age of 262±27Ma and an initial 187Os/ 188Os of 0.12460±0.00011 (γ Os(t)=-0.5±0.1). The age is in good agreement with the previously reported U-Pb zircon age, indicating that the Re-Os system remained closed for most samples since the intrusion emplacement. They have near-chondritic γ Os(t) values ranging from -0.7 to -0.2, similar to those of the Lijiang picrites and Song Da komatiites. Exceptionally, two samples from the roof zone and one from upper sequence exhibit radiogenic γ Os(t) values (+0.6 to +8.6), showing minor contamination by the overlying Emeishan basalts.The PGE-rich ores contain relatively high PGE and small amounts of sulfides (generally less than 2%) and the abundance of Cu and PGE correlate well with S, implying that the distribution of these elements is controlled by the segregation and accumulation of a sulfide liquid. Some ore samples are poor in S (mostly <800ppm), which may due to late-stage S loss caused by the dissolution of FeS from pre-existing sulfides through their interaction with sulfide-unsaturated flowing magma. The combined study shows that the Xinjie intrusion may be derived from ferropicritic magmas. The sharp reversals in Mg#, Cr/FeO T and Cr/TiO 2 ratios immediately below Units 2-4, together with high Cu/Zr ratios decreasing from each PGE ore layer within these cyclic units, are consistent with multiple magma replenishment episodes. The sulfides in the cumulate rocks show little evidence of PGE depletion with height and thus appear to have segregated from successive inputs of fertile magma. This suggests that the Xinjie intrusion crystallized from in ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| ردمك: | 978-0-00-287682-7 0-00-287682-5 |
| تدمد: | 0016-7037 |
| العلاقة: | Geochimica et Cosmochimica Acta; http://www.scopus.com/mlt/select.url?eid=2-s2.0-79951515280&selection=ref&src=s&origin=recordpageTest; Geochimica Et Cosmochimica Acta, 2011, v. 75 n. 6, p. 1621-1641; 8668973; 1641; 195325; WOS:000287682500013; eid_2-s2.0-79951515280; 1621; http://hdl.handle.net/10722/139218Test; 75 |
| DOI: | 10.1016/j.gca.2011.01.009 |
| الإتاحة: | https://doi.org/10.1016/j.gca.2011.01.009Test http://hdl.handle.net/10722/139218Test |
| رقم الانضمام: | edsbas.6B524689 |
| قاعدة البيانات: | BASE |
| ردمك: | 9780002876827 0002876825 |
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| تدمد: | 00167037 |
| DOI: | 10.1016/j.gca.2011.01.009 |