内蒙古中部白垩纪碱性花岗岩的发现及意义

作者通过对内蒙古苏尼特左旗地区深成侵入岩类同源岩浆演化系列的研究，首次发现了一个典型的碱性花岗岩杂岩体．在详细的地质填图和室内研究的基础上，按照岩石谱系单位的划分原则，对其作了进一步的解体，并对该碱性花岗岩超单元的岩石学、矿物学、岩石化学以及稀土元素地球化学进行了综合研究．同时，对杂岩体的成因性质及岩浆起源的物化条件作了初步探讨。认为沙尔塔拉碱性花岗岩超单元是形成于早白垩世的Ａ型花岗岩，是该地区造山期后陆壳整体抬升过程中拉张环境下岩浆活动的产物，它的发现将对本区构造岩浆活动发展史的认识具有重要的意义．

DISCOVERY AND IMPORTANCE OF CRETACEOUS ALKALI GRANITE IN THE CENTRAL INNER MONGOLIA

he authors have first discovered a typical alkali granite complex body through the study of plutonic intrusion rocks of co-magmatic evolution series.Based on geological mapping and researching,complex body has been subdivided according to rock-lineage unit division principle. The petrology, mineralogy, petrochemistry and rare earth element geochemistry of the alkali granite superunit have been studied. The genetic property and physical-chemical condition of magma source has also been discussed. The authors recognize that the alkali granite superunit of Setala is A-type granite in Lower Cretaceous period, was formed by magmatic activity in tensional environment in the process of the whole continental crust uplift in postorogenic. Its discovery will be of importance for the understanding of tectonomagmatic activity history in this area.