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本文从岩石化学和矿物学角度,研究了江苏及皖东新生代玄武质岩石,初步确定它们属于碱性玄武岩系列;是喜山运动早、中、晚三个岩浆旋迥的产物;主要岩石类型有橄榄玄武岩、碱性橄榄玄武岩、碧玄岩、霞石岩以及由分异作用或混染作用形成的碱性辉绿岩、拉斑辉绿岩和方沸正长岩;岩石的碱性程度自老至新、自东向西增强;由于岩浆的分离结晶作用和受硅铝层混染,引起一系列岩石化学和矿物成分的规律性变化。本文还试图根据玄武质岩浆类型和包裹的超镁铁包体,以及普通辉石、歪长石、石榴石大晶体的成分,估计岩浆源的深度,自东向西由35～50公里加深到75～90公里左右。
In this paper, from the perspective of petrochemistry and mineralogy, the Cenozoic basaltic rocks in Jiangsu and eastern Anhui have been studied, and they are initially identified as alkaline basalt series. They are the products of the early, middle and late magmatic rotation in the Ximaoshan Movement. The main rock types There are olivine basalts, basaltic olivine basalts, bixonites, nepheline rocks, and basic diabase, plaque diabase and amphibolitic syenite formed by differentiation or intermixing; the basicity of rocks varies from old To new and enhanced from east to west; a series of regular changes in the chemistry and mineralogy of rocks have been caused by the separation and crystallization of magma and contamination by silica-alumina layers. This article also attempts to estimate the depth of the magma source from 35-50 km from east to west based on the basaltic magma type and the ultramafic inclusions of the par- ticles, as well as the composition of the pyroxene, crooked feldspar and garnet large crystals 75 ~ 90 km or so.