Geochronology and geochemical characteristics of volcanic rocks section in Manzhouli Xinyouqi, Inner-Mongolia.
文献类型：期刊论文
| 作者 | Chen ZhiGuang; Zhang LianChang; Zhou XinHua; Wan Bo; Ying JiFeng; Wang Fei |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2006-12-01 |
| 卷号 | 22期号:12页码:2971-2986 |
| 关键词 | Late Jurassic Petro-geochemistry Postorogenic Extension Xinyouqi Volcanic Rocks Section |
| ISSN号 | 1000-0569 |
| 文献子类 | Article |
| 英文摘要 | Mesozoic volcanic rocks section in Manzhouli Xinyouqi, Inner-Mongolia is mainly composed of trachy-andesite, trachyte and rhyolite. Ar-40-Ar-39 dating of lower section trachy-andesites and middle section rhyolites give a plateau age of 162.6 +/- 0.7 Ma and 162.0 +/- 0. 8 Ma, and zircon U-Pb determination of upper section trachy-andesites yields a concordant age of 149.5 +/- 1.7Ma. This indicates that these volcanic rocks were formed in two gyrations of volcanic explosion in late Jurassic. The major elements of the samples show that geochemical characteristics of rocks in the lower and upper section are similar, which indicate that they formed from the same magma source. Both of them are relatively high in SiO2, Al2O3, K2O and total alkaline and low in MgO and Mg#, belonging to the cale-alkaline series with high K contents and demonstrating total BEE and LREE enrichment with insignificant Eu anomalies (delta Eu = 0. 72 similar to 0. 90) and intense fractionation between LREE and HREE. The primitive mantle-normalized spidergrams are characterized by LILE enrichment and HFSE depletion, especially for a significantly negative Nb-Ta anomaly. Isotopic geochemistry shows that the value of epsilon(Nd) (t) range from -0.5 to 1.3, and (Sr-87/Sr-86)(i) from 0. 705078 to 0. 713891. Rhyolites of middle rocks section are high in SiO2 and low in MgO, FeO and Al2O3, belonging to the calc-alkaline series. Rhyolites display the same REE pattern and epsilon(Nd) (t) (-0. 7 similar to -0. 9) with trachy-andesite and trachyte, while Eu contents appears intense negative Eu anomalies(delta Eu = 0. 32), and are characterized by Sr,Ti,Ba and P significant depletion and the high (Sr-87/Sr-86),value(0.710044-0.71389t). The geochemical feature of rachy-andesites and trachytes suggest their origination were from a metasomatized mantle wedge or depleted mantle, which had been modified by previous subducted ocean slab. According to the correlation between the rachy-andesites and trachytes, it is inferred that the trachytes were derived from the differentiated crystallization of andesitic magmas. On the other hand, the rhyolites possess a clear "crustal" signature, possibly attributed to the crustal contamination during the magma ascent or anatexis of lower-middle crust in response to the andesitic underplating. Combining their genchemical characteristics with previous studies of this area, the late Jurassic volcanism in Manzhouli Xinyouqi was formed in the post-orogenic stage in which a rapid lithospheric extension must have accurred, resulting in the decompressional melting of the pre-existent metasomatized lithospheric mantle. It is possibly that these Mesozoic volcanic rocks in Manzhouli Xinyouqi were formed by the collision-postorogenic extension of Mongolia-Okhotsc ocean during late Jurassic. |
| WOS关键词 | EXTENSION ; CHINA ; ARC |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000245660400014 |
| 出版者 | SCIENCE PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/65940]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Chen ZhiGuang |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 3.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China |
| 推荐引用方式 GB/T 7714 | Chen ZhiGuang,Zhang LianChang,Zhou XinHua,et al. Geochronology and geochemical characteristics of volcanic rocks section in Manzhouli Xinyouqi, Inner-Mongolia.[J]. ACTA PETROLOGICA SINICA,2006,22(12):2971-2986. |
| APA | Chen ZhiGuang,Zhang LianChang,Zhou XinHua,Wan Bo,Ying JiFeng,&Wang Fei.(2006).Geochronology and geochemical characteristics of volcanic rocks section in Manzhouli Xinyouqi, Inner-Mongolia..ACTA PETROLOGICA SINICA,22(12),2971-2986. |
| MLA | Chen ZhiGuang,et al."Geochronology and geochemical characteristics of volcanic rocks section in Manzhouli Xinyouqi, Inner-Mongolia.".ACTA PETROLOGICA SINICA 22.12(2006):2971-2986. |
入库方式： OAI收割
来源：地质与地球物理研究所
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