摘要
莆田渡边位于长乐—南澳断裂带的北段,分布一套未变形变质中酸性火山岩组合;英安岩中锆石U-Pb表面年龄可分为2组,分别为76~88 Ma和98~124 Ma,加权平均值分别为（82.9±1.6）Ma和（105.4±3.0）Ma。研究认为前者代表火山作用过程中锆石结晶年龄;后者为火山作用过程中捕获的围岩锆石年龄,与研究区内广泛分布的早白垩世花岗岩体年龄相同。岩石地球化学特征表明,渡边英安质-流纹质火山岩组合具有I型花岗岩特征,属壳幔混源型岩浆,可能来源于晚中生代俯冲板片的重熔。
Dubian county of Putian city locates in the northern part of Changle-Nan＇ao fault zone,where distributes a series of intermediate acid volcanic rocks,without deformation and metamorphism in the zone.The mineralization and age of zircons indicate that the zircons can be devided in two types,and the LA-ICP-MS zircon 206Pb/238 Uages are 76~88Ma and 98~124Ma with weighted average age of 82.9±1.6Ma and 105.4±3.0Ma respectively.The former represents time is close to age of miarolitic granite in the process of volcanism and the latter represents time is close to age of magamatism of surrounding rock,which is close to the intrusion time of the widely distributed early Cretaceous granite in the area.The geochemistry characteristics show that the decitic-rhyolitic volcanic volcanic rocks belongs the migma of lower crust and mantle materials with the characteristic of I type granitoid derived,which melting may be from late Mesozoic subduction plate.
出处
《福建地质》
2016年第3期163-171,共9页
Geology of Fujian
