【摘要】 浙西北萧山—诸暨地区晚侏罗世末期花岗(石英)闪长岩与早白垩世末期(辉石)闪长岩具有以下地球化学特征:低硅、贫碱、富钙镁铁,弱负铕异常,稀土配分曲线右倾,富集K,Rb,Ba,Th,U等,亏损Nb,Ta等,Sr,Ti亏损不明显。晚侏罗世末期花岗岩与早白垩世末期花岗(斑)岩均具有高硅、富碱、贫钙镁,强负铕异常的特征;晚侏罗世侵入岩具"V"型稀土配分曲线,强富集K,Rb,Th,U等,相对富集Nb,Ta,强亏损Ba,Sr,Ti等特征;早白垩世侵入岩具右倾稀土配分曲线,富集K,Rb,Th,U等,亏损Nb,Ta,Sr,Ti,Ba不亏损等特征。岩石构造地球化学图解分析表明,晚侏罗世末期I-A型花岗岩类成岩构造环境具有从俯冲挤压碰撞作用向后碰撞或后造山作用演化的特征;早白垩世末期(高分异)I型花岗岩类岩石主要与火山-次火山喷发-侵入作用关系密切,成岩构造环境主要与区域伸展作用有关。更多还原

【Abstract】 The Late Jurassic granite(quartz)diorite and Early Cretaceous(pyroxene)diorite are geochmically characterized by low silicon,poor in alkaline,rich in Ca,Mg,Fe,weak negative Eu anomaly,rightward REE curve,enrichment of K,Rb,Ba,Th,U,depletion of Nb,Ta,less depletion of Sr,Ti.The late granite of Late Jurassic Epoch and late granite(porphyry)of Cretaceous Epoch share the geochemical characteristics of high Si,enrichment of alkalis,poor in Ca,and Mg,strong negative Eu anomaly,.However,the former is characterized by the "V" type REE distribution patterns,and strong enrichment of K,Rb,Th,U,relative rich in Nb,Ta,strong depletion of Ba,Sr,Ti.etc.And the latter by the rightward REE curve,enrichment of K,Rb,Th,U,and depletion of Nb,Ta,Sr,Ti,but no depletion of Ba.Petrological,geotectonic and geochemical plots show that the diagenetic tectonic environment of the type I-A intrusive rock at the end of the late Jurassic evolved from the subduction extrusion collision to post-collision or post-orogeny.At end of the late Early Cretaceous the highly differentiated type Igranite is closely related to the volcanic-sub-volcanic eruption-intrusion.The diagenetic tectonic setting is mainly related to regional extension.更多还原