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赣东北-浙西北登山群和松木坞群中火山岩的地球化学
引用本文:赵风清,金文山,甘晓春,孙大中.赣东北-浙西北登山群和松木坞群中火山岩的地球化学[J].地质调查与研究,1997(2).
作者姓名:赵风清  金文山  甘晓春  孙大中
作者单位:地矿部天津地质矿产研究所!天津300170(赵风清,金文山,甘晓春),中科院广州地球化学研究所!广州510640(孙大中)
摘    要:赣东北-浙西北新元古代登山群和松木坞群主要由板岩、砂岩、流纹岩、流纹质英安岩、玄武岩和玄武质安山岩组成,火山岩的Rb-Sr和Sm-Nd等时线年龄以及流纹岩中单颗粒锆石U-Pb年龄显示其成岩时代为800-900Ma。登山群和松木坞群火山岩呈双峰式产出,其中镁铁质火山岩在化学成分上呈现出演化程度较高的特点(evolvednature),高强场元素(Ti、Nb、Ta等)相对于碱土元素未发生明显亏损,反映其形成于大陆裂谷环境。镁铁质火山岩具低的Nd值,表明其来源于弱亏损的地幔源,也可能遭受一定程度的地壳混染作用改造。酸性火山岩在化学成分上表现出S型火山岩特点,但其变化于-1.9~+28,指示其为先存的长英质基底分熔作用的产物,但存在强烈的地慢物质添加作用。

关 键 词:华南  登山群和松木坞群  火山岩  地球化学  大陆裂谷

GEOCHEMISTRY OF THE VOLCANICS IN DENGSHAN GROUP AND SONGMUWU GROUP FROM NE JIANGXI PROVINCE AND NW ZHEJIANG PROVINCE
Zhao Fengqing,Jin Wenshan,Gan Xiaochun.GEOCHEMISTRY OF THE VOLCANICS IN DENGSHAN GROUP AND SONGMUWU GROUP FROM NE JIANGXI PROVINCE AND NW ZHEJIANG PROVINCE[J].Geological Survey and Research,1997(2).
Authors:Zhao Fengqing  Jin Wenshan  Gan Xiaochun
Abstract:The Dengshan Group and Songrmuwu Group in NE Jiangxi Province and NWZhejiang Province are composed mainly of slates, sandstones, sandstones,rhyolitic andesites,basalts and basaltic andesites in Which the volcanics show bindal suite. The volcanics have beendated by Rb-Sr isochron, Sin-Nd isochron and single zircon U-Pb methods and obtained thecrystallization age between 900 Ma and 800 Ma. The basalts and basaltic andesites of DengshanGp. and Songmuwu Gp. exhibit relatively evolved nature in composition and show an enrichmentOf incompatible elements, implying continental rift setting. The rhyolites and rhyolitic daciteswith S-type characteristics have the ENd value from -- 1. 9 to + 2. 8, indicating an origin by partialmelting of old sedimentary protoliths and in-vololving variable amount addition of mantlecomponents.
Keywords:South China  Dengshan Group and Songmuwu  Group  volcanics  Geochemistry  continental rift setting
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