| “全国第四届火山学术研讨会”一号通知 |
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| 引用本文： | 沈其韩,耿元生,王新社,吴春明.“全国第四届火山学术研讨会”一号通知[J].岩石矿物学杂志,2005,24(1):31-31. |
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| 作者姓名： | 沈其韩 耿元生 王新社 吴春明 |
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| 作者单位： | 中国地质科学院地质研究所 北京100037
(沈其韩，耿元生，王新社)，中国地质科学院地质研究所 北京100037(吴春明) |
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| 基金项目： | 中国地质调查资助项目 ( 199913 0 0 0 0 0 6) |
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| 摘 要： | 为交流我国火山研究与监测方面的成果，迎接在我国举办的国际火山学与地球内部化学协会(IAVCEI)2006年国际学术大会，进一步推动我国火山工作的深入研究和发展，中国灾害防御协会火山专业委员会、中国矿物岩石地球化学学会火山及地球内部化学专业委员会、IUGG中国IAVCEI委员会和广西地震局，定于2005年11月在广西北海市共同主办“全国第四届火山学术研讨会”，欢迎全国同行及有兴趣的各界人士参会。有关事项如下：
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| 关 键 词： | 斜长角闪岩 地球化学 同位素年龄 板内裂陷或大陆边缘裂陷 阿拉善地区 |
| 文章编号： | 1000-6524(2005)01-0021-11 |
Petrology, geochemistry, formation environment and ages of Precambrian amphibolites in Alxa region |
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| SHEN Qi-han,GENG Yuan-sheng,WANG Xin-she and WU Chun-ming.Petrology, geochemistry, formation environment and ages of Precambrian amphibolites in Alxa region[J].Acta Petrologica Et Mineralogica,2005,24(1):31-31. |
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| Authors: | SHEN Qi-han GENG Yuan-sheng WANG Xin-she and WU Chun-ming |
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| Abstract: | Petrology, geochemistry, formation environment and isotopic geochronology of Precambrian amphibolites in Alxa area are reported in this paper. Amphibolites in different group complexes, formation complexes and complex rock bodies all crop out in layers, and their protoliths are mainly ferrian tholeiite characterized geochemically by high potassium and titanium as well as rich REE and LREE. These characteristics are remarkably different from features of typical oceanic tholeiite, TH_1 and TH_2 tholeiite of Archean rock assemblages. Various geochemical diagrams indicate that amphibolites are mainly formed in an intraplate environment characterized by intraplate depression or epicontinental faulted depression. Isotopic geochronology shows that amphibolite in Diebusige group complex was formed in Neo_archean. ~(39)Ar_~(40)Ar age and isotopic age of hornblende from biotite_bearing amphibolite are 1?918 Ma and 1?919 Ma respectively, suggesting that they underwent metamorphism of amphibolite faces in Paleoproterozoic. Amphibolite in Bayanwulashan formation complex was formed between (2?271) Ma and 2?264 Ma. Amphibolite in Boluositanmiao gneiss complex was intruded by granitic gneiss of 1?818 Ma and 1?839 Ma. According to geochemical characteristics of amphibolite in the complex and the same sort of rocks in Bayanwulashan formation complex, it is concluded that it was formed in early Paleoproterozoic. Accurate isotopic chronological data of amphibolite from Delhetongte formation complex in Alxa Group are not available, but the average zircon ion probe age of garnet_muscovite_biotite_quartz_schist in the same layer is 1?363 Ma, which indicate that the amphibolite was probably formed in Meso_proterozoic. |
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| Keywords: | amphibolite geochemistry isotopic age intraplate depression or epicontinental faulted depression |
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