Origin of clinopyroxene megacrysts in the late Mesozoic and Cenozoic basalts from the North China Craton and their constraints on the magma process of host rocks: a case of the Junan and Hebi
文献类型：期刊论文
| 作者 | Xiao Yan1,2; Zhang HongFu1; Fan WeiMing3 |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2008 |
| 卷号 | 24期号:1页码:65-76 |
| 关键词 | North China Craton clinopyroxene magacrysts alkaline basalts magma underplating petrogenesis |
| ISSN号 | 1000-0569 |
| 文献子类 | Article |
| 英文摘要 | Major- and trace-elements as well as Sr-Nd isotopes of clinopyroxene megacrysts in the late Mesozoic and Cenozoic alkaline basaltic rocks from the North China Craton have been analyzed in this paper. There are two types of clinopyroxene megacrysts (Al-augite and salites) in the Cenozoic alkaline basalts and one type (Al-augite) in the late Mesozoic basalts. The Cenozoic Al-augite megacrysts is different from the late Mesozoic ones in many aspects of major- and trace-elements and Sr-Nd isotopes. The Cenozoic Al-augite megacrysts are characterized by high SiO(2), convex upward Chondrite-normalized REE pattern, and higher LILE and radioactive element contents. Their Sr and Nd isotopic compositions are more depleted than those of the host rocks. The late Mesozoic A1-augite megacrysts are characterized by low SiO(2) and LREE enriched patterns with lower LILE, some HFSE and radioactive element contents. In addition, the Sr and Nd isotopic compositions of the late Mesozoic megacrysts are less depleted than those of the host rocks. The characteristics of texture, mineral compositions and geochemistry as well as the Fe-Mg partitioning between the crystal and the melt indicates that the Al-augites in the Cenozoic basalts represent high-pressure crystallization products of alkaline basaltic melts. Thus, both of clinopyroxene megacrysts and host basalts could be derived from a same primitive magma. However, the Al-augites in the late Mesozoic basaltic rocks represent accidentally-included xenocrysts of basaltic components which had crystallized in the depth from a previously melting episode. The more depleted Sr-Nd isotopic compositions of Cenozoic megacrysts compared with those of host alkaline basalts and tholeiites demonstrate that even the alkali basalts could not completely represent primitive magma initiating in asthenosphere. That is to say, the Cenozoic alkaline basalts were more or less modified by some enriched Sr-Nd isotopic components during their eruption. Meanwhile, the tholeiites were not the products formed only by fractional crystallization of alkaline basaltic magma or different degrees of partial melting. It may result from the contribution of lithospheric mantle materials or crust contamination in magma chamber to alkali basaltic magmas. |
| WOS关键词 | EASTERN CHINA ; TRACE-ELEMENT ; ISOTOPIC GEOCHEMISTRY ; MANTLE INTERACTION ; VOLCANIC-ROCKS ; INNER-MONGOLIA ; MAJOR-ELEMENT ; ND ; XENOLITHS ; PB |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000254774000005 |
| 出版者 | SCIENCE PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/69936]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Xiao Yan |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China 3.Chinese Acad Sci, Guangzhou Inst Geochem, Guangzhou 510640, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xiao Yan,Zhang HongFu,Fan WeiMing. Origin of clinopyroxene megacrysts in the late Mesozoic and Cenozoic basalts from the North China Craton and their constraints on the magma process of host rocks: a case of the Junan and Hebi[J]. ACTA PETROLOGICA SINICA,2008,24(1):65-76. |
| APA | Xiao Yan,Zhang HongFu,&Fan WeiMing.(2008).Origin of clinopyroxene megacrysts in the late Mesozoic and Cenozoic basalts from the North China Craton and their constraints on the magma process of host rocks: a case of the Junan and Hebi.ACTA PETROLOGICA SINICA,24(1),65-76. |
| MLA | Xiao Yan,et al."Origin of clinopyroxene megacrysts in the late Mesozoic and Cenozoic basalts from the North China Craton and their constraints on the magma process of host rocks: a case of the Junan and Hebi".ACTA PETROLOGICA SINICA 24.1(2008):65-76. |
入库方式： OAI收割
来源：地质与地球物理研究所
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