| 北秦岭官坡地区高压—超高压榴辉岩岩相学及变质作用研究 |
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| 引用本文： | 胡能高,赵东林.北秦岭官坡地区高压—超高压榴辉岩岩相学及变质作用研究[J].矿物岩石,1995,15(4):1-9. |
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| 作者姓名： | 胡能高 赵东林 |
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| 作者单位： | 西安地质学院资经系 |
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| 摘 要： | 北秦岭官坡地区的榴辉岩及含柯石英榴辉岩产在帮岭岩群的北侧，主要由绿辉石和石榴石组成，部分石榴石和绿辉石中含柯石英包体。此外还含有退变质的多硅白云母、角闪石、黝帘石和纳长石等矿物，根据变质矿物之间的替代关系及共生组合规律，榴辉岩退变质作用可划分为四个阶段，各阶段代表性矿物组合依次为：柯石英＋绿辉石＋石榴石；石英＋绿辉石＋石榴石；多硅白云母＋绿辉石＋石榴石＋石英；角闪石＋斜长石＋白云母＋黑云母。这四个
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| 关 键 词： | 柯石英 榴辉岩 岩相学 变质作用 |
PETROGRAPHY AND METAMORPHISM STUDY ON HIGH-UITRAHIGH PRESSURE ECLOGITE FROM GUANPO ARE, NORTHERN QINLING MOUNTAIN |
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| HuNenggao,Zhao Donglin,Xu Baiqing,Wang Tao.PETROGRAPHY AND METAMORPHISM STUDY ON HIGH-UITRAHIGH PRESSURE ECLOGITE FROM GUANPO ARE, NORTHERN QINLING MOUNTAIN[J].Journal of Mineralogy and Petrology,1995,15(4):1-9. |
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| Authors: | HuNenggao Zhao Donglin Xu Baiqing Wang Tao |
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| Abstract: | High-ultrahigh pressure eclogites were discovered in the Qinling complex of Guanpo reaa,northern Qinling mountainin 1993.They occur as lenes,layered units and blocks to the south of mountain the northern boundary of Qinling complex.Well-preserved eclogites have typi-cal assemblage of more than 90 vol% euhedral omphacite(Jd:25 41%)and garnet with minor rutile. Grams of omphacite and garnet range from 0.5 to 1mm in size and display equilibrium re-lations.Euhedral to subhedral rutile occurs mainly as inclusion in omphacite or garnet,d,nd less of-fen as in terstitial phases between grains of the major minerals coesite and coesite pseudomorphs are recognized as inclusion in both omphacite and garnet in a few eclogites.Most relict anhedral crystal of zoesites are surrounded by low-relief quartz pseudomorph with rodical fractions.Phen-gite,hornblende,zoisite and albite(plagioclase)occur as retrograde minerals in eclogites.Composi-tions of garnets and omphacites are similar with that of Dabie mountains and west-Alps continen-tal-type eclogites.The metamorphic evolution of ultrahigh pressure eclogite is divided in to four pe-rieds according to the minerals growth relations.The characteristic mineral assemblages are:co-esiteemphacite-garnet;quartz-omphacite-garnet;phengite-omphacite-garnet-quartz and horn-blende-plagioclase-muscovite-biotite. The retrogressive p-T path formed by the four periods sug-gests that its pressure transmission was very fast, its thermal transmission very slow. The p-T path of coesite-bearing eclogites suggests that its exhumational speed is very quick. The formation and exhumation are due to the local stress concentration and the reverse shearing floW in the deep phase of the early evolution stage of Zhuxia fault belt. |
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| Keywords: | northern Qinling mountain coesite eclogite ultrahigh pressure metamorphism |
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