论文部分内容阅读
巴家滩岩体是下扬子庐枞火山盆地内的重要岩体之一。野外调查发现,巴家滩岩体有两期岩浆活动形成,细粒石英正长岩脉贯穿于中粗粒辉石二长岩之中。分别对辉石二长岩和石英正长岩开展了LA-ICPMS锆石U-Pb定年,结果分别为133.2Ma±1.2Ma和130.1Ma±1.7 Ma,分别对应了砖桥组喷发旋回和双庙组喷发旋回。庐枞盆地火山岩从早期至晚期,岩浆有向富碱演化的趋势,而巴家滩岩体两期岩浆的精确定年和岩石学特征指示其岩浆演化趋势和火山岩一致,表现为次火山岩的特征。庐枞地区中生代侵入岩可以划分为三期:134Ma～132Ma,131Ma～128Ma和127Ma～124Ma。
Bajiatan rock mass is one of the most important rock masses in the Lower Yangtze Luzhong volcanic basin. The field survey found that there are two phases of magmatic activity in the Bajiatan rock mass, and the fine-grained, quartz-bearing dyke veins run through the middle-coarse grained rock. LA-ICPMS zircon U-Pb dating of pyroxene feldspar and quartz syenite were carried out respectively, and the results were 133.2Ma ± 1.2Ma and 130.1Ma ± 1.7Ma, respectively corresponding to the ebb and flow of the Zhuanqiao Formation and Shuangmiao Group eruption cycle. Volcanic rocks in Luzong basin tended to evolve from alkali to alkali in early to late years. The precise dating and petrological characteristics of the two phases of the magmatic rocks in the Bajiatan rock mass indicate that the magmatic evolution trend is consistent with that of the volcanic rocks, which is characterized by subvolcanic rocks. The Mesozoic intrusive rocks in Luzong area can be divided into three phases: 134Ma ~ 132Ma, 131Ma ~ 128Ma and 127Ma ~ 124Ma.