中国东南部中生代基性岩脉时空分布与形成机理  

Time-space distribution and formation mechanism of the Mesozoic mafic dikes in Southeast China

作　　者：娄峰[1] 马浩明[2] 刘延勇 李宏卫[1] 杨燕娜[1] 陈耀均 

机构地区：[1]中山大学地球科学系,广东广州510275 [2]广东省地震局,广东广州510070 [3]广州市地质调查院,广东广州510440 [4]广东省佛山地质局,广东佛山528000

出　　处：《地学前缘》2011年第1期15-23,共9页Earth Science Frontiers

基　　金：高等学校博士学科点基金项目(20070558033)

摘　　要：中国东南部发育的基性岩脉见于中生代各个时期,其年龄从内陆至沿海逐渐变新,与区内花岗岩年龄有相同的变化趋势,但两者活动高峰期不重合。基性岩脉主要发育于花岗岩体内部的拉裂带,鲜见穿过花岗岩上方或周围的沉积变质盖层。中生代各时期的基性岩脉与相应时期的中酸性和基性火山岩浆活动具有清晰的分带现象。进一步研究表明,基性岩脉与同期基性火山岩应是同源不同相的产物,而中酸性喷发的岩浆与基性喷发(侵入)的岩浆,则可能分别来自壳内熔融层和壳下(地幔)熔融层或壳内岩浆层的上部和下部。中酸性与基性岩浆活动的"错峰"现象和基性岩脉带的"迁移"现象,均与本区中生代陆壳系统的内能变化有关。Mafic dikes are found forming in different periods of the Mesozoic in Southeast China.Ages of the dikes show a spatial variation as that of the Mesozoic granites of this area,i.e.becoming younger from inland to coastal region,but the activity-fastigia of mafic dikes and granites are not synchronous,and that of the former occurred relatively behind.Mafic dikes usually occurred limited in tensional cracks developed within granite bodies,seldom to perforate into the fractures in the country rocks of granite bodies.The mafic dikes generally occurred within the corresponding mafic volcanic belt that was located on the west of the intermediated-acid eruption belt of the same time,indicating that the mafic magma of eruption and intrusion should have been derived from the same source,i.e.,the bottom part of the crustal magma layer or the mantle melt layer.Both reducing scales of the intermediated-acid eruption and the seaward migration of mafic eruption and intrusion belts after the Late Jurassic suggest decreasing crustal temperature of this area in the Late Mesozoic.

关 键 词：基性岩脉 花岗岩 壳内熔融层 岩浆喷发带 

分 类 号：P588.124[天文地球—岩石学]