摘要
Phlogopite-amphibole-pyroxenitexenolithscontainedinthealkalibasic-ultrabasicsubvolcaniccomplexinLangao,shaanxiProvinece,arecomposedofdiopside,Ti-richpargasite,phlogopiteapatite,spheneandilmenite,whichhavesubsolidusmetamorphism-deformationtexturessuchastriple-points,cataclasticboundariesandkink-bands,MineralChemicalcharacteristicsshowthatthediopside,Ti-richPargasiteandphlogopitearederivedfromthemantleandaretheprioductsofmantlemetasomatism,Comparedwithnormalmantle-derivedspinel-lherzolites,thexenolithsareenrichedinTiO2,Fe2O3,CaO,Na2OandK2O,withapparentdepletioninMgO,Chondrite-normalizedREEpatternsandprimordial-mantlenormalizedtraceelementsdatashowthattheyareenrichedinREE(EspeciallyLREE)andincompatibletraceelements,Thepetropraphic,mineralogicalandpetrochemicalcharacteristicsindicatethatthexenolithsaremetasomatizedmantlexenoliths,whichofferstheevidenceformantlemetasomatismandrepresentstheanomalousmantlebeneaththeEarlyPaleozoicriftinnorthernDabaMountains,Theagentsofmantlemetasomatismareprobablyderivedfromtherisingofmantlehotplumes,Thepriocessesofmetasomatismvariedfromlimited-rangefluidmetasomatismindeepmantle(>90km)topervasivemetasomatismofsilicatemelt.
出版日期
1997年04月14日(中国期刊网平台首次上网日期,不代表论文的发表时间)