CAJ | 학술논문

大田地区中生代岩浆岩普遍具有高硅、高铝的特点。汤泉岩体花岗闪长岩中锆石LA-ICP-MS U-Pb年龄为168±3 Ma,其样品中La/Yb较高,Eu亏损不明显,具有高Sr、低Y的地球化学特征,符合埃达克质岩特征,其形成与地壳增厚有关,处于挤压构造背景下;NNE向脉岩群样品锆石LA-ICP-MS U-Pb加权平均年龄为138±3 Ma,部分脉岩群样品可划分为强过铝质,脉岩群样品中La/Yb较小,Eu绝对值较小,亏损严重,为挤压阶段末期形成;太华岩体La/Yb较高,Eu轻度亏损,Rb-Sr等时线年龄为114.89±2.2 Ma,是西太平洋板块俯冲、地壳减薄的伸展构造背景下形成。
대전지구중생대암장암보편구유고규、고려적특점。탕천암체화강섬장암중고석LA-ICP-MS U-Pb년령위168±3 Ma,기양품중La/Yb교고,Eu우손불명현,구유고Sr、저Y적지구화학특정,부합애체극질암특정,기형성여지각증후유관,처우제압구조배경하;NNE향맥암군양품고석LA-ICP-MS U-Pb가권평균년령위138±3 Ma,부분맥암군양품가화분위강과려질,맥암군양품중La/Yb교소,Eu절대치교소,우손엄중,위제압계단말기형성;태화암체La/Yb교고,Eu경도우손,Rb-Sr등시선년령위114.89±2.2 Ma,시서태평양판괴부충、지각감박적신전구조배경하형성。
Mesozoic magmatic rocks in Datian area,Fujian province,are usually rich in SiO2 and Al2O3 content.Tangquan granodiorite which yielded zircon LA-ICP-MS U-Pb age of 168±3 Ma has high La/Yb and Sr,slightly Eu depletion,and poor in Y,is similar to adakite in geochemistry,indicate that it＇s formed in compressional setting related to crust thickening.NNE-trending granite veins which yielded zircon LA-ICP-MS U-Pb age of 138＋3 Ma has low La/Yb value and intensive Eu depletion,indicate that it＇s formed in late stage of compression process.Taihua granite which yielded Rb-Sr isochron age of 114.89±2.2 Ma has high La/Yb value and slightly Eu depletion,may be formed in extensional setting related to crust thinning when West Pacific subduction.