火山口堆积及其相模式:以松辽盆地白垩系营城组为例  

Pyroclastics deposition and its facies model of crater:An example from Yingcheng formation in Songliao basin,Cretaceous,NE China

作　　者：沈艳杰[1] 程日辉[1] 王腾飞[1] 于振锋[1] 

机构地区：[1]吉林大学地球科学学院,吉林长春130061

出　　处：《中南大学学报（自然科学版）》2014年第6期2006-2013,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(40972074;41202085)

摘　　要：松辽盆地东南缘露头区出露白垩系营城组火山口堆积,火山碎屑堆积特征显示,营城组时期火山活动具有阶段性,营1段时期为酸性岩浆活动期,营2段时期为火山活动间歇期,营3段时期先后有中基性岩浆和酸性岩浆活动发生。恢复火山口堆积岩性的时间先后和空间位置关系,建立火山口堆积相模式。研究结果表明:营一段时期火山活动以岩浆含气量大的喷发为特征,喷发分4个阶段,即蒸汽喷发—蒸汽岩浆喷发—岩浆喷发—火山活动期后的岩浆侵出/侵入活动。营3段火山活动分为早-中期的中基性岩浆喷发和晚期的酸性岩浆的侵入/侵出:那中基性岩浆喷发活动包括产生火山弹的"爆炸"式岩浆喷发—"爆炸"式向"喷溢/溢流"式岩浆喷发的过渡—"喷溢/溢流"式岩浆喷发—"爆炸"式岩浆喷发4种形式;酸性岩浆的侵入/侵出活动包括岩浆侵入围岩引起隐爆—岩浆侵出导致形成柱状节理岩穹2个阶段。Crater depositions of Yingcheng formation outcropped in the outcrop area in the southeast margin of Songliao Basin, Cretaceous, NE China. Sedimentation characteristics show that the volcanic activity of Yingcheng formation occurred in stages. Main are the acidic magma activated in the first member of Yingcheng formation, and the volcano inactivity period in the second member of Yingcheng formation, however, the intermediate-basic magma activated firstly, and then the acidic magma activated in the third member of Yingcheng formation. The relationship of chronological order and spatial position of the crater deposition was restored, and based on those studies the facies models of the crater deposition were established. The results show that, the volcanic activity characteristics are that a mass of gas was produced in the process of volcanic eruption in the first member of Yingcheng formation. The volcanic eruption process consisted of four stages, i.e., steam explosion – steam magma eruption-magmatic eruption-magmatic extrusive/magmatic intrusive after the volcanic activity. The intermediate-basic magma eruption in the early stage, and the acidic magmatic intrusive/magmatic extrusive activity in the late stage both composed the volcanic activity in the third member of Yingcheng formation. Intermediate-basic magma activities were composed of 4 forms： “Explosive” type magmatic eruption with volcanic bombs produced-transition from “Explosive” type magmatic eruption to “Effusive/overflow” magmatic eruption-“Effusive/overflow” type magmatic eruption-“Explosive” type magmatic eruption. The acidic magmatic intrusive/magmatic extrusive activity is composed of the county rock cryptoexplosion caused by magmatic intrusive activity and columnar joints dome were generated by the magmatic extrusive activity.

关 键 词：火山口 火山碎屑岩 相模式 营城组 松辽盆地 

分 类 号：P586[天文地球—岩石学] P588.14[天文地球—地质学]