Identification and petrogenesis of potassic volcanic rocks with "ultrapotassic" characteristics from Maqiang area in Lhasa block. | |
Wang, BD (Wang BaoDi); Chen, LK (Chen LingKang); Xu, JF (Xu JiFeng); Liu, HF (Liu HongFei); Chen, JL (Chen JianLin); Kang, ZQ (Kang ZhiQiang) | |
刊名 | ACTA PETROLOGICA SINICA |
2011 | |
卷号 | 27期号:6页码:1662-1674 |
关键词 | Potassic-ultrapotassic volcanic rocks Post-collisional magmatism Temporal distribution Maqiang area Lhasa block |
ISSN号 | 1000-0569 |
英文摘要 | It is generally accepted that the post-collisional potassic and ultrapotassic magmatism are erupted from western to eastern in temporal in Lhasa block of Tibetan Plateau. However, this study has identified the potassic volcanic rocks from the Maqiang area in central of Lhasa block, which formed at similar to 21.3Ma by (40)Ar-(39)Ar dating. These potassic rocks are geochemical similar to ultrapotassic rocks, e. g., high in MgO (> 3%) and K(2)O/Na(2)O (K(2)O/Na(2)O > 2). The high MgO contents of potassic rocks in studying area caused for late-altered dolomite and they are more similar to potassic volcanic rocks although they show some "ultrapotassic" characteristics. Geochemically and tectonically, these potassic rocks in studying area are similar to the potassic-ultrapotassic rocks occurring along N-S rifts in the western Lhasa block. The enrichment in light rare earth elements (LREE), large ion lithophile elements (LILE, e. g., Rb, Ba and Th) and depletion in HFSE (e. g., Nb, Ta and Ti), and high initial (87)Sr/(86)Sr and low epsilon(Nd)(t) values of the potassic rocks in studying area, indicated that they were probably generated by partial melting of a metasomatic enrichment mantle related to early subduction events. Recognition of the potassic rocks in the Maqiang area imply that post-collisional potassic-ultrapotassic magmtism did not migrate from west to east in the Lhasa block. In other words, the post-collisional potassic and ultrapotassic lava in the Lhasa block were might erupted at the same time. And we suggest that the formation of the Miocene potassic-ultrapotassic volcanic rocks and N-S rifts in the Lhasa block were probably triggered by slab break-off of the India continent lithosphere during northern intra-continent subduction in early Miocene. |
学科主题 | 火成岩岩石学 |
WOS关键词 | MANTLE SOURCE CHARACTERISTICS ; WESTERN TIBETAN PLATEAU ; SOUTHERN TIBET ; ISOTOPIC COMPOSITIONS ; SUBDUCTED SEDIMENTS ; SW TIBET ; CONSTRAINTS ; MAGMATISM ; PB ; EVOLUTION |
WOS研究方向 | Geology |
语种 | 中文 |
出版者 | SCIENCE PRESS |
WOS记录号 | WOS:000292995600008 |
内容类型 | 期刊论文 |
源URL | [http://119.78.100.197/handle/2HKVOGP0/39271] |
专题 | 中国地质调查局 |
作者单位 | Inst Geol Survey Tibet Autonomous Reg, Lhasa 850000, Peoples R China |
推荐引用方式 GB/T 7714 | Wang, BD ,Chen, LK ,Xu, JF ,et al. Identification and petrogenesis of potassic volcanic rocks with "ultrapotassic" characteristics from Maqiang area in Lhasa block.[J]. ACTA PETROLOGICA SINICA,2011,27(6):1662-1674. |
APA | Wang, BD ,Chen, LK ,Xu, JF ,Liu, HF ,Chen, JL ,&Kang, ZQ .(2011).Identification and petrogenesis of potassic volcanic rocks with "ultrapotassic" characteristics from Maqiang area in Lhasa block..ACTA PETROLOGICA SINICA,27(6),1662-1674. |
MLA | Wang, BD ,et al."Identification and petrogenesis of potassic volcanic rocks with "ultrapotassic" characteristics from Maqiang area in Lhasa block.".ACTA PETROLOGICA SINICA 27.6(2011):1662-1674. |
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