河南省南阳双河油田沉凝灰岩浅析

本文简略介绍了河南省泌阳凹陷内最近发现的沉凝灰岩的基本特征。该岩石见于双河油田某井,它是由成分单一的玄武岩岩屑、斜长石晶屑,玻屑及绿泥石化和硅化的填隙物组成。此外,尚含有极少量的石英及燧石质陆源碎屑。岩石中已碳化的含量甚多的动、植物碎屑所显现的流水交错纹层,表明了岩石的过渡型特征。 文章分析了具有玄武岩结构的岩屑中的长石以及晶屑斜长石是属于钠长石和更长石类,它们是较基性的斜长石成岩变化中钠长石化的产物。沉凝灰岩的上下固岩属第三系断陷盆地内扇三角洲正常沉积,而该沉凝灰岩中的火成碎屑是同沉积期水底基性喷发(溢)物。 泌阳凹陷西南断裂构造带,是深达上地幔的边界控制断裂,资料表明在该边界断裂拉张活动的某个阶段,能为岩浆的上侵、喷溢、喷发提供通道。

PRELIMINARY ANALYSIS OF SEDIMENTARY TUFF IN SHUANGHE OILFIELD,NANYANG,HENAN

In this paper, the basic characteristics of sedimentary tuff are introduced which has recently been discovered in Miyang Depression, Henan Province. The tuff consists of the basaltic debris, plagioclastics, hyaloclastic fragments, and silicated or chloritized interstitial materials, with the addition of minimal terrigenous quartzic and cherty clastics. Furthermore, the current cross lamination shown by abundant animal and plant remains contained in the rock indicates its transitional characteristics.The plagioelase in the basaltic debris and crystalloclastic plagioclase are classified into the albite or oligoclase.They are products of the albitization of more basic plagioclase during diagenesis.The sedimentary tuff occurs in the fan deltaic depositonal system in the Tertiary faulted basin，while pyroclastics in the sedimentary tuff are the syndepositional basic effusion under water.The southwest faults of Miyang Depression are boundary faults which stretch to the upper mantle.It is shown that they can provide passages of the emplacment and eruption of basic magma at some extensional stage.