苏北盆地海州群火山岩地球化学特征及其大地构造学意义

Geochemical characteristics and tectonic significances of volcanic rocks in Haizhou Group,Northern Jiangsu Basin

苏北盆地元古代晚期的海州群中发育大量火山岩,以石英角斑岩为主,细碧岩次之,角斑岩类稀少,属于细碧岩—石英角斑岩组合类型。海州群火山岩富碱、富钠,具双峰值特征,该岩系的主量元素、微量元素和稀土元素地球化学特征表明,它形成于非造山张性环境,为裂陷槽,是与晚元古代罗迪尼亚超大陆裂解有关的岩浆作用的产物。

In the Northern Jiangsu Basin,large amounts of volcanic rocks generated in the Haizhou Group during the late Proterozoic Era.Quartz keratophyre accounts for the largest proportion,spilite the second,and keratophyre the least.The volcanic rocks in the Haizhou Formation are rich in alkali and Na,and are characterized by bimodal distribution.The geochemical features of major,trace and rare elements indicate that the volcanic rocks formed in tensional environment,i.e.taphrogenic trough.They were related to the Rodinia Supercontinent during the late Proterozoic Era.