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| 桂北元宝山宝坛地区约825Ma镁铁-超镁铁岩的地球化学及其地质意义 | |
| 引用本文： | 葛文春,李献华,梁细荣,王汝成,李正祥,周汉文.桂北元宝山宝坛地区约825Ma镁铁-超镁铁岩的地球化学及其地质意义[J].地球化学,2001,30(2):123-130. |
| 作者姓名： | 葛文春 李献华 梁细荣 王汝成 李正祥 周汉文 |
| 作者单位： | 1. 中国科学院广州地球化学研究所, 2. 南京大学地球科学系, 3. 西澳大利亚大学地质和地球物理系, |
| 基金项目： | 国家杰出青年科学基金资助项目!（ 49725309），中国科学院重大项目! B（ KZ951- B1- 413） |
| 摘 要： | 镁铁－超镁铁岩的岩石学和地球化学特征表明，元宝山超镁铁岩中橄榄石的Fo为78－83，岩石具有明显的包橄结构，具有LREE亏损，低Th/Nb和La/Nb比值以及高（t)值（约＋5），是来源于亏损地幔低程度部分熔融的岩浆堆晶的产物；宝坛地区镁铁－超镁铁岩富集LREE，具有高的Th/Nb,La/Nb比值和低的（t)值（－0．45－7．01），是镁铁质岩浆上升，结晶过程中与地壳物质混染（AFC）的结果，超镁铁岩与澳大利亚Garidner岩脉群具有相似的不相容元素分布型式和Nd(t) 值，是导致新元古代Rodinia超大陆裂解的地幔柱熔融的产物。 |
| 关 键 词： | 镁铁－超镁铁岩 地球化学 地幔柱 广西壮族自治区 稀土元素 微量元素 钐－钕同位素 |
| 文章编号： | 0379-1726(2001)02-0123-08 |
| 修稿时间： | 2000年7月12日 |
Geochemistry and geological implications of mafic-ultramafic rocks with the age of～825 Ma in Yuanbaoshan-Baotan area of northern Guangxi |
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| GE Wen-chun,LI Xian-hua,LIANG Xi-rong,Wang Ru-Cheng,LI Zheng-xiang,ZHOU Han-wen.Geochemistry and geological implications of mafic-ultramafic rocks with the age of～825 Ma in Yuanbaoshan-Baotan area of northern Guangxi[J].Geochimica,2001,30(2):123-130. | |
| Authors: | GE Wen-chun LI Xian-hua LIANG Xi-rong Wang Ru-Cheng LI Zheng-xiang ZHOU Han-wen |
| Abstract: | Petrological and geochemical characteristics show that mafic-ultramafic rocks in Yuanbaoshan area have remarked olivine peritectic texture with Fo values of 78～83 in olivines, depletion of LREE, low ratios of Th/Nb, La/Nb and high εNd(t) values (about +5), implying they are magmatic cumulus derived from partial melting at lower degree of depleted mantle; while the mafic-ultramafic rocks in Baotan area have enrichment of LREE, high ratios of Th/Nb, La/Nb and low εNd(t) values (-0.45～-7.01 ), indicating they are the result of contamination with crustal material during the ascending and crystallization process of mafic magma, similar to a process of AFC. The ultramafic rocks in this area have similar incompatible elements distribution pattern and εNd(t) values with Gairdner dyke swarm of Australia, which is the melting product of mantle plume which led to the breakup of late Proterozoic Rodinia Supercontinent. |
| Keywords: | mafic- ultramafic rocks geochemistry mantle plume Guangxi Zhuangzu Zizhiqu |
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