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| 北京西山髫髻山组火山岩的地球化学特征与岩浆起源 | |
| 引用本文： | 李伍平,路凤香,李献华,周瑶琪,孙善平,李家振,章大港.北京西山髫髻山组火山岩的地球化学特征与岩浆起源[J].岩石矿物学杂志,2001,20(2):123-133. |
| 作者姓名： | 李伍平 路凤香 李献华 周瑶琪 孙善平 李家振 章大港 |
| 作者单位： | 1. 长安大学地球科系,中国科学院广州地球化学研究所, 2. 石油大学油气资源与环境地质研究所, 3. 中国地质大学地球科学学院, 4. 中国科学院广州地球化学研究所, 5. 中国地质大学地质系, |
| 基金项目： | 国土资源部"九五”重大基础项目(9501111); 国家自然科学基金资助项目(49602037)及国家杰出青年科学基金项目(49725300) |
| 摘 要： | 对北京西山髫髻山组粗安岩斜长石Ar-Ar年龄测定获得全坪年龄和等时线年龄分别为148.91Ma±2.98Ma和146.60Ma±2.93Ma(相关系数r=0.9997),本文将其时代划为晚侏罗世.元素-同位素地球化学显示,西山髫髻山组火山岩主要为高钾钙碱性系列,低Ti\K,高Al\Ca和Na,轻稀土元素富集,Eu异常不明显,大离子亲石元素Rb\Sr\Ba等相对富集,高场强元素Nb\Ta\Ti\Zr\Hf相对亏损,Nd\Sr和Pb同位素比值较低,反映出火山岩形成于岛弧或活动大陆边缘,其源岩为富集地幔.据此认为髫髻山组火山岩形成于陆内挤压环境,由中生代玄武质岩浆底侵于下地壳-壳幔过渡带诱发古老(太古宙)的玄武质岩石部分熔融形成的. |
| 关 键 词： | 髫髻山组 下地壳－壳幔过渡带 玄武质岩石 晚侏罗世 火山岩 陆内造山带 北京 岩浆 地球化学特征 |
| 文章编号： | 1000-6524(2001)02-0123-11 |
| 修稿时间： | 2000年10月11 |
Geochemical Features and Origin of Volcanic Rocks of Tiaojishan Formation inWestern Hills of Beijing |
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| LI Wu-ping,LU Feng-xiang,LI Xian-hu,ZHOU Yao-qi,SUN Shan-ping,LI Jia-zhen,ZHANG Da-gang.Geochemical Features and Origin of Volcanic Rocks of Tiaojishan Formation inWestern Hills of Beijing[J].Acta Petrologica Et Mineralogica,2001,20(2):123-133. | |
| Authors: | LI Wu-ping LU Feng-xiang LI Xian-hu ZHOU Yao-qi SUN Shan-ping LI Jia-zhen ZHANG Da-gang |
| Institution: | LI Wu-ping 1,2,LU Feng-xiang3,LI Xian-hua1,ZHOU Yao-qi4,SUN Shan-ping5,LI Jia-zhen5,ZHANG Da-gang4 |
| Abstract: | Tiaojishan Formation in Western Hills of Beijing was dated at Late Jurassic based on the Ar-Ar ages for tachyandesites (all plateau ages and isochrone ages of plagioclase are respectively 148.91±2.98 Ma and 146.60±2.93 Ma). Geochemistry of elements and isotopes show that volcanic rocks of Tiaojishan Formation are mainly of high-K calc-alkaline series characterized by indistinct Eu anomaly, relative enrichment of large-ion lithophile elements such as.Rb, Sr and Ba, relative depletion of high field-strength elements (e.g. Nb, Ta, Ti, Zr, Hf ), and low Nd, Sr and Pb ratios, suggesting the features of island -arc and active continental margin and enriched mantle. The authors think that volcanic rocks of Tiaojishan Formation were derived from partial melting of old-age (Archean) basaltic rocks of the lower crust and the crust-mantle transitive zone by the underplating of basaltic magma during intrcontinental orogeny. |
| Keywords: | Tiaojishan Formation partial melting the lower crust-the crust-mantle transitive zone basaltic rocks intrcontinental orogen zone Western Hills of Beijing |
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