The Mesozoic high-Sr granitoids in the northern marginal region of North China Craton: geochemistry and source region.
文献类型：期刊论文
| 作者 | Liu, HT; Sun, SH; Liu, JM; Zhai, MG |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2002-07-01 |
| 卷号 | 18期号:3页码:257-274 |
| 关键词 | high-Sr granites Mesozoic source region North China Craton |
| ISSN号 | 1000-0569 |
| 文献子类 | Article |
| 英文摘要 | The Mesozoic high-Sr granitoids (HSRG) are widely distributed in the northern marginal region of the North China Craton and mainly consist of quartz diorites, granodiorites, quartz monzonites and adamellites, which are petrographically characterized by common occurrences of varying types of perthites. Based on analyses of 61 samples from 16 HSRG intrusions, they exhibit markedly high Na(2)O and Al(2)O(3) contents in their bulk compositions and can readily be classified into two groups: (1) low-silica rocks with SiO(2) between 53%similar to60%, and (2) high-silica ones with SiO(2) between 65%similar to73%, but only one sample is observed between 60%similar to65% SiO(2). Thus HSRG in the region display an apparent "bimodal" distribution. Majority of high-silica rocks are high-K calc-alkaline, but the low-silica rocks show a remarkable diversity in their affinity from low-K island tholeiitic, through calc-alkaline and high-K calc-alkaline, to shoshonitic. Their notable trace element geochemistry, including strongly-enriched strontium, strongly-depleted heavy rare earth elements (HREE) and nearly absence of negative europium anomalies, thus making them distinguishable from other granites occurred in the same region. By detailed comparison between HSRG and the partial melts generated experimentally from dehydration melting of various rocks commonly occurred within continental crust, it is suggested that the low-silica rocks from HSRG were derived from partial melting of basaltic amphibolites, but the high-silica rocks were generated from partial melting of intermediate-to-acid igneous protoliths, both under high pressure (assumedly greater than or equal to 1.5 GPa) and high temperature (assumedly > 850similar to900 degreesC) conditions. The partial melts extracted from the residual assemblages composed mainly of garnet + clinopyroxene +/- orthopyroxene +/- amphibole +/- quartz would unequivocally display the major- and trace-element geochemistry as the high-Sr granitoids do. The HREE depletions of HSRG could largely be ascribed to the residual garnet as exhibited by dehydration melting experiments, and both high-Sr abundance and absence of negative Eu anomalies could be largely contributed by nearly completely fusing of feldspar components of the protoliths into partial melts. Furthermore, they also indicate no significant plagioclase fractionation occurred in-between from melt segregation to magma emplacement. This implies that the HSRG were originated directly from mafic and/or intermediate-acid igneous protoliths in the overthickened continental lower crusts and may generally represent the primary granitic magmas with little differentiation before the onset of major phase of crystallization. The residual solid assemblages of granulite and/or eclogite facies are suggested to become new constituents of the continental lower crust below where HSRG emplaced, or to be delaminated down to the upper mantle by their density inversion. |
| WOS关键词 | CORDILLERA BLANCA BATHOLITH ; COLVILLE IGNEOUS COMPLEX ; CONTINENTAL-CRUST ; CALC-ALKALINE ; EXPERIMENTAL DEFORMATION ; MAGMATIC PROCESSES ; MELT SEGREGATION ; ROCKS ; GENESIS ; PETROGENESIS |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000177516200001 |
| 出版者 | SCIENCE CHINA PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/78018]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Liu, HT |
| 作者单位 | Chinese Acad Sci, Key Lab Mineral Resources, Inst Geol & Geophys, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Liu, HT,Sun, SH,Liu, JM,et al. The Mesozoic high-Sr granitoids in the northern marginal region of North China Craton: geochemistry and source region.[J]. ACTA PETROLOGICA SINICA,2002,18(3):257-274. |
| APA | Liu, HT,Sun, SH,Liu, JM,&Zhai, MG.(2002).The Mesozoic high-Sr granitoids in the northern marginal region of North China Craton: geochemistry and source region..ACTA PETROLOGICA SINICA,18(3),257-274. |
| MLA | Liu, HT,et al."The Mesozoic high-Sr granitoids in the northern marginal region of North China Craton: geochemistry and source region.".ACTA PETROLOGICA SINICA 18.3(2002):257-274. |
入库方式： OAI收割
来源：地质与地球物理研究所
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