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Petrogenesis and magmatic-hydrothermal evolution time limitation of Kelumute No. 112 pegmatite in Altay, Northwestern China: Evidence from zircon U-Pb and Hf isotopes | |
Zheng-Hang Lv; Hui Zhang; Yong Tang; Shen-Jin Guan | |
2012 | |
发表期刊 | Lithos |
卷号 | 154期号:2页码:374-391 |
摘要 | Granitic pegmatites and associated rare-metal deposits, unique features in the Altay orogen, are located in a key tectonic position of the southern Central Asian Orogenic Belt (CAOB) and document the tectonic evolution of the Paleo-Asian Ocean. The Kelumute No. 112 pegmatite, which intruded into the Jideke two-mica granites, hosts abundant rare-metal (e.g., U, Be, Nb, Ta) ore deposits and ranks only second to the Koktokay No. 3 pegmatite in both size and reserves. To explore the evolution time limitation of magmatic, magmatic-hydrothermal and hydrothermal stages in the pegmatite magma system, the tectonic setting and the genetic relationship between pegmatites and granites, this study presents zircon U-Pb and Hf isotopic compositions of the Kelumute No. 112 pegmatite and the wall rocks (two-mica granite and biotite granite) as determined by LA-ICPMS and LA-MC-ICPMS. The weighted mean Pb-206/U-238 ages of the internal textural zones of the pegmatite, including zones I, II, III, V and VI, are 238.3 +/- 2.0 Ma, 233.5 +/- 3.7 Ma, 1883 +/- 1.7 Ma, 218.8 +/- 1.9 Ma and 210.7 +/- 1.6 Ma, respectively. Wall rocks of two-mica granite and biotite granite are dated at 445.6 +/- 4.3 Ma and 455.6 +/- 5.4 Ma, respectively. Zircons from the Kelumute No. 112 pegmatite have lower positive epsilon(Hf)(t) values (+0.03 to +235). with T-DM model ages of 1112-1225 Ma. Wall rocks show similar zircon epsilon(Hf)(t) values (-1.41 to +4.13) and T-DM model ages (1172 to 1515 Ma). However, three xenocrystic zircons from the granites are characterized by larger negative epsilon Hf(t) values (-5.85 to -9.83) and older T-DM model ages (1839 to 2090 Ma). Thus, the following conclusions can be drawn: 1) the Kelumute No. 112 pegmatite and its wall rocks (Jideke two-mica granite and biotite granite) have no genetic relationship, as indicated by the large gaps between their formation ages. However, they did originate from a common source composed of ancient crust and mantle-derived materials under two different tectonic settings; 2) the magmatic, magmatic-hydrothermal transition and hydrothermal stages of the No. 112 pegmatite magma lasted for similar to 5 Ma, similar to 23 Ma and similar to 22 Ma, respectively; and 3) the No. 112 pegmatite magma was most likely formed in a post-collision tectonic setting, indicating that block amalgamation and collisional orogeny of the CAOB continued into the Triassic. |
关键词 | Magmatic–hydrothermal Evolution Zircon Upb Age Hf Isotope Pegmatite Granite Altay Xinjiang |
收录类别 | SCI |
语种 | 英语 |
文献类型 | 期刊论文 |
条目标识符 | http://ir.gyig.ac.cn/handle/352002/5130 |
专题 | 地球内部物质高温高压实验室_地球内部物质高温高压实验室_期刊论文 |
推荐引用方式 GB/T 7714 | Zheng-Hang Lv,Hui Zhang,Yong Tang,et al. Petrogenesis and magmatic-hydrothermal evolution time limitation of Kelumute No. 112 pegmatite in Altay, Northwestern China: Evidence from zircon U-Pb and Hf isotopes[J]. Lithos,2012,154(2):374-391. |
APA | Zheng-Hang Lv,Hui Zhang,Yong Tang,&Shen-Jin Guan.(2012).Petrogenesis and magmatic-hydrothermal evolution time limitation of Kelumute No. 112 pegmatite in Altay, Northwestern China: Evidence from zircon U-Pb and Hf isotopes.Lithos,154(2),374-391. |
MLA | Zheng-Hang Lv,et al."Petrogenesis and magmatic-hydrothermal evolution time limitation of Kelumute No. 112 pegmatite in Altay, Northwestern China: Evidence from zircon U-Pb and Hf isotopes".Lithos 154.2(2012):374-391. |
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