安徽滁县中生代火山岩岩石化学及斜长石特征

安徽滁县中生代火山岩盆地为长江中下游一系列火山岩盆地之一,它位于张八岭隆起的东侧,受平行于郯庐断裂的次级断裂控制,形成北北东向的断陷盆地。盆地基岩较老,西部直接覆盖在震旦亚界灯影组之上,其分布受古地形的制约(图1),南部、东部不整合在早古生界地层之上。

PETROCHEMISTRY OF MESOZOIC VOLCANIC ROCKS IN THE CHU COUNTY,ANHUI PROVINCE AND THE CHARACTERISTIES OF PLAGIOCLASES

The volcanic basin in the Chu County,Anhui Province,is one of Mesozoic volcanic basins in the middle-lower Yangtze Valley.This paper deals with the petrochemistry and the characteristics of trace elements of volcanic rocks in this volcanic series.The plagioclases from these rocks were studied by methods of oil immersion,universal stage,X-ray diffraction,Infra-red absorption spectroscopy and wet chemical analysis.The results obtained help us to preliminarily understand the nature,the assimilation and contamination of magma.The Chu basin differs from other basins,as the Ningwu basin,in the alternation and mineralization of valcanic rocks and in other aspects,that can be explained by the presence or absence of evaporited bed in country rocks,i.e.the assimilation and contamination of Na₂O and K₂O.