皖南晚震旦世硅质岩的成因研究

On the Origin of the Upper Sinian Cherts of Southern Anhui

研究区位于华南下扬子区构造活动带，地层剖面中有火山英安岩，硅质岩中含火山碎屑，它们的存在表明本区在晚震旦世曾发生火山活动并影响沉积物成份。元素分析显示本区硅质岩化学组成与火山成因硅质岩相似，高的Ｂａ含量，具与壳型花岗岩相似的稀土元素分布模式，指示本区硅质岩的硅源可能来自海底火山喷发。文章同时还讨论了硅质的搬运和沉积作用。

The study area is in the tectonic mobile belt of the lower Yangzi region,South China.The volcanic dacite is exposed in the stratigraphic section and the volcanic detritus distributed in the chert.Their presence indicates that in this area the volcanic activity has happened and might have influenced these deposits.The elemental analysis shows that the cherts in this area are similar to those of volcanic genesis in chemical compositions.High Ba content and REE patterns similar to crustal type granite suggest that the siliceous matters may come from the oceanic volcanic emanation in this area.The transportation and deposition of these siliceous matters are discussed in this paper also.