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| 满洲里南部白音高老组流纹岩锆石U-Pb定年及岩石成因 | |
| 引用本文： | 苟军,孙德有,赵忠华,任云生,张学元,付长亮,王晰,魏红艳.满洲里南部白音高老组流纹岩锆石U-Pb定年及岩石成因[J].岩石学报,2010,26(1):333-344. |
| 作者姓名： | 苟军 孙德有 赵忠华 任云生 张学元 付长亮 王晰 魏红艳 |
| 作者单位： | 1. 吉林大学地球科学学院,长春,130061 2. 吉林大学地球科学学院,长春,130061;西北大学大陆动力学国家重点实验室,西安,710069 3. 核工业240研究所,沈阳,110032 4. 中国国土资源航空物探遥感中心,北京,100083 |
| 基金项目： | 国家“973”项目(2009CB219303)、中国核工业地质局项目和西北大学大陆动力学国家重点实验室开放课题基金联合资助 |
| 摘 要： | 满洲里南部白音高老组火山岩主要由流纹岩组成,含少量珍珠岩和流纹质凝灰岩。LA-ICPMS锆石U-Pb定年结果显示,流纹岩形成于141~139Ma的早白垩世早期。岩石地球化学研究表明,火山岩具有高硅富碱、贫钙镁和高FeOT/MgO比值的特征; 稀土丰度总量较高(∑REE介于103×10-6~488×10-6),轻重稀土分馏明显［(La/ Yb)N=4.12~30.94)］,Eu负异常显著(δEu=0.12~0.46); 微量元素以富集Rb、Th、U、K,强烈亏损Ba、Sr、P、Ti,中等亏损Nb、Ta和高Ga/Al值为特征,与A-型花岗岩特征相似。锆石176Hf/177Hf比值介于0.282785~0.282970之间,εHf(t)值均为正值,介于3.78~9.98之间。流纹岩岩浆来源于斜长石稳定区玄武质下地壳物质的部分熔融,形成于非造山板内伸展构造环境。 |
| 关 键 词： | 白音高老组 流纹岩 锆石U-Pb年龄 岩石成因 满洲里 |
| 收稿时间： | 9/1/2009 12:00:00 AM |
| 修稿时间： | 2009/11/11 0:00:00 |
Zircon LA-ICPMS U-Pb dating and petrogenesis of rhyolites in Baiyingaolao Formation from the southern Manzhouli, Inner-Mongolia |
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| Gou J,Sun DY,Zhao ZH,Ren YS,Zhang XY,Fu CL,Wang X and Wei HY.Zircon LA-ICPMS U-Pb dating and petrogenesis of rhyolites in Baiyingaolao Formation from the southern Manzhouli, Inner-Mongolia[J].Acta Petrologica Sinica,2010,26(1):333-344. | |
| Authors: | Gou J Sun DY Zhao ZH Ren YS Zhang XY Fu CL Wang X and Wei HY |
| Institution: | College of Earth Sciences, Jilin University, Changchun 130061, China;College of Earth Sciences, Jilin University, Changchun 130061, China;No.240 Institute of Nuclear Industry, Shenyang 110032, China;College of Earth Sciences, Jilin University, Changchun 130061, China;No.240 Institute of Nuclear Industry, Shenyang 110032, China;China Aero Geophysical Survey & Remote Sensing Center for Land and Resources, Beijing 100083, China;College of Earth Sciences, Jilin University, Changchun 130061, China;College of Earth Sciences, Jilin University, Changchun 130061, China |
| Abstract: | The volcanic rocks of Baiyingaolao Formation in the southern Manzhouli arc composed of rhyolites and a little amount of perlites and rhyolitic tufts. U-Pb age determinations of zircon by LA-ICPMS show the rhyolites were formed at Early Cretaceous, and their formation ages ranged from 141Ma to 139Ma. The geochemical study suggests that rhyolites are rich in silicon, alkalis, poor in calcium, magnesium and have high FeO~T/MgO ratio. All samples have similar characteristics of REE patterns which are characterized by relatively high total REE contents (∑REE = 103×10~(-6)～488×10~(-6) ), significant fractionation of HREE and LREE (La/Yb) = 4.12～30.94] and strong negative Eu anoalies (δEu=0.12～0.46). The trace element geochemistry are characterized evidently by enrichment of Rb, Th, U, K, strong depletion of Ba, Sr, P, Ti, mediate depletion of Nb, Ta and higher Ga/Al ratio. The geochemical characteristics of rhyolites show an affinity with the A-type granite. The initial ~(176) Hf/~(177) Hf ratios of the magmatic zircons from rhyolites vary in 0.282785～0.282970 and the corresponding ε_(Hf)(t) values are positive ranging from 3.78 to 9.98. The characteristics above indicate that the rhyolitic magma was origTinated from partial melting of basaltic lower crustal materials in the plagioclase-stable field. Combining with the regional researching results,we suggest that the rhyolites were formed in an intra-plate anorogenic extensional setting. |
| Keywords: | Baiyingaolao Formation Rhyolite Zircon U-Pb dating Petrogenesis Manzhouli |
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