松辽盆地东缘下白垩统营城组二段火山碎屑岩的发育特征  

Characteristics of Volcaniclasitic Rocks Developed in Member 2,Yingcheng Formation,Lower Cretaceous,in the Eastern Margin of Songliao Basin

作　　者：李飞[1] 程日辉[1] 王璞珺[1] 侯景涛[2] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]中国石油长庆油田分公司第三采油厂,银川750006

出　　处：《吉林大学学报（地球科学版）》2009年第5期803-810,共8页Journal of Jilin University：Earth Science Edition

基　　金：国家'973'项目(2006CB701403)

摘　　要：通过精细的野外剖面测量,发现松辽盆地东缘营城组二段中发育熔岩、凝灰岩和凝灰质砂岩。凝灰岩包括熔结凝灰岩、岩屑晶屑凝灰岩、灰球泥粒凝灰岩和角砾凝灰岩。这表明作为火山活动间歇期的营城组二段沉积期依然存在一定规模的火山活动,其沉积作用具有独特的火山和沉积双重控制的特点,区别于正常的沉积作用。营城组二段是一套介于火山岩和陆源碎屑岩之间的过渡岩性,物源既有来自同期火山喷发,也有来自营城组一段和营城组下段以及更老的地层的风化剥蚀。由于存在火山物质和陆源剥蚀物质的双重物源及存在火山物质堆积和沉积作用的双重机理,这套岩石在类型上具有特殊性。存在特殊的火山-沉积作用类型,主要为冲积平原上热碎屑流河道沉积、冲积平原泛滥盆地上热基浪沉积、冲积平原泛滥盆地上空落火山灰云沉积。The volcanic lava, tuff and tuffaceous sandstones were recognised in member 2 of Yingcheng Formation, Cretaceous in the survey of outcropped geological section with a detailed measurement in the eastern margin of Songliao basin. The tuff rocks include ignimbrite, lithic crystal tuff, ash ball tuff and breccia tuff. It indicates that a certain scale of volcanic activities still existed during the forming of member 2 of Yingcheng formation, which was a stage without Strong volcanic activities. This kind of deposition distinguished from the normal deposition, has a special characteristics controlled by both volcanism and sedimentation. The member 2 of Yingcheng formation is a suit of transition rocks between volcanic rocks and terrigenous clastic rocks, and the provenances derived not only from syngenetic volcanic eruption, but also from the member 1 and the lower member of Yingcheng Formation, as well as the weathering of older strata. These suits of rocks are special in types because of the existence of the two kinds of provenances including volcanic substance and terrigenous denudation substance, and the two kinds of mechanisms including volcanic accumulation and normal sedimentation. It is indicated that special volcanic-deposit types were existed, during the stage of member 2 of Yingcheng Formation which are pyroelastie flow channel deposits in alluvial plain, base surge deposits and air-fall volcanic ash deposits in flooding basin.

关 键 词：松辽盆地东缘 营城组 火山碎屑岩 火山-沉积作用 物源区分析 

分 类 号：P588.21[天文地球—岩石学]