长白山天池火山CZK07钻所揭示的火山地层层序和火山作用特征

发布时间：2018-11-22 13:53

【摘要】：长白山天池火山是地球上最大的活火山之一,其形成演化过程复杂。本文在对天池周边工程钻岩芯资料系统整理的基础上,以本次在北坡"U"形谷中开展的CZK07钻岩芯为研究对象,揭示天池火山白头山期火山锥体之下的火山喷发物物质组成和火山地层层序变化特征,分析火山活动过程中伴生火山作用的表现形式及断裂构造的活动特征。CZK07钻岩芯较全面地记录了天池火山早期活动、早期造盾、晚期造盾和造盾之后前造锥阶段火山活动的火山地层层序。其中天池火山早期活动记录由蚀变较强的流纹岩组成;早期造盾由军舰山组橄榄玄武岩夹辉石玄武岩组成,形成于上新世;晚期造盾由漫江组粗面质(橄榄)玄武岩夹粗面岩组成,形成于早更新世早期,且至少存在3期火山活动;造盾之后前造锥阶段的火山喷发物由小白山组粗面质熔岩及碎屑岩组成,形成于早更新世晚期。伴生的火山作用记录表现为造盾晚期的玄武质次火山活动,造锥阶段的粗面质次火山活动及伴随发生的蚀变和隐爆现象,及全新世大爆发阶段的隐爆角砾、热液蚀变和次火山活动等现象。天池火山地区晚新生代以来高角度张剪性断层的活动强烈,推测与"U"形谷的形成密切相关。
[Abstract]:Tianchi Volcano in Changbai Mountain is one of the largest active volcanoes on the earth. On the basis of systematical analysis of drilling core data in the surrounding engineering of Tianchi, this paper takes CZK07 core drilling in the "U" shape valley on the north slope as the research object. To reveal the composition of volcanic eruptions and the characteristics of volcanic stratigraphic sequence changes under the pyramides of Baitoushan volcanic epoch in Tianchi volcano. This paper analyzes the manifestation of associated volcanism and the active characteristics of fault structure in the course of volcanic activity. The early activities and early shield of Tianchi volcano are recorded by CZK07 core. The volcanic stratigraphic sequence of volcanic activity in the pre-coning stage after late shield and shield making. The early record of Tianchi volcano is composed of altered rhyolite, the early shield is composed of olivine basalt and gabbro basalt, which was formed in Pliocene. The late stage of shield formation is composed of coarse (olivine) basalt intercalated with coarse surface rocks in Manjiang formation, which was formed in early Pleistocene and had at least 3 periods of volcanic activity. The volcanic eruptions in the pre-coning stage after shield making are composed of coarse surface lava and clastic rocks of Xiaobaishan formation and formed in the late early Pleistocene. The accompanying volcanism recorded as Black Tortoise subvolcanic activity in late shield making stage, coarse surface subvolcanic activity in cone making stage and associated alteration and hidden explosion phenomena, and cryptoexplosive breccia in Holocene eruption stage. Hydrothermal alteration and subvolcanic activity. The activity of high angle tensional shear faults in Tianchi volcanic area is strong since the late Cenozoic, which is inferred to be closely related to the formation of "U" shaped valley.
【作者单位】：沈阳地质矿产研究所;沈阳师范大学古生物学院;
【基金】：国土资源部科技司公益性行业基金项目(编号201211095-5) 中国地质调查局项目(编号12120114085601和1212011220435)联合资助成果
【分类号】：P317

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