CAJ | 학술논문

志留系滔河口组是一套发育于北大巴山地区的火山岩-火山碎屑岩-沉积岩组合.在1:10000地质填图和大比例地质剖面实测基础上,通过详细的火山碎屑岩相序和组构分析,本文在滔河口组火山-地层中共识别和划分出22个岩相,5个相组合类型.区域岩相测量与对比揭示,滔河口组火山-沉积宏观序列自下而上由玄武岩相(一般下部为块状粗粒/细粒玄武岩相、上部为枕状玄武岩相)、凝灰角砾岩相、再沉积富辉石火山碎屑砾岩相、无结构或叠瓦状凝灰质粗砾岩相、凝灰质砂岩相、生物灰岩相或泥岩相构成.岩相组合横向变化显示滔河口组古火山活动西强东弱,火山活动类型为斯托柏林型(Strombolian-type eruption)喷发.相对地,研究区西部火山-沉积序列发育较为完整.滔河口组的地层序列与岩石组合与板内火山活动产物相似,本文认为北大巴山地区志留系滔河口组火山岩-火山碎屑岩-沉积岩组合形成于洋岛或海山构造环境,是板内拉伸作用的产物.
지류계도하구조시일투발육우북대파산지구적화산암-화산쇄설암-침적암조합.재1:10000지질전도화대비례지질부면실측기출상,통과상세적화산쇄설암상서화조구분석,본문재도하구조화산-지층중공식별화화분출22개암상,5개상조합류형.구역암상측량여대비게시,도하구조화산-침적굉관서렬자하이상유현무암상(일반하부위괴상조립/세립현무암상、상부위침상현무암상)、응회각력암상、재침적부휘석화산쇄설력암상、무결구혹첩와상응회질조력암상、응회질사암상、생물회암상혹니암상구성.암상조합횡향변화현시도하구조고화산활동서강동약,화산활동류형위사탁백림형(Strombolian-type eruption)분발.상대지,연구구서부화산-침적서렬발육교위완정.도하구조적지층서렬여암석조합여판내화산활동산물상사,본문인위북대파산지구지류계도하구조화산암-화산쇄설암-침적암조합형성우양도혹해산구조배경,시판내랍신작용적산물.
The Taohekou Formation is constituted with volcanic, volcaniclastic and sedimentary rock. Based on the systematic field work, which including 1:10000 field survey and large scale profile drawing, it could be distinguished twenty-two lithofacies and then grouped into five lithofacies associations from the deposits. According to the comparative studying among different sections, we summarized the generalized succession of the volcanic-sedimentary deposits, which to top is basalt facies(lower is massive basalts, upper is pillow basalts), tuff breccia, resedimented pyroclast-rich (or pyroxene-rich) lapillistone facies, structureless or imbricate tuffaceous conglomerate facies, tuffaceous sandstone facies(locally interbedded with calcarenite), biolithite or mudstone facies. The intensity of volcanism of west area is more powerful than the ones of east area. The type of eruption is Strombolian. The succession of Taohekou Formation, combines with geochemical of volcanic rocks or pyroxene, suggest that the tectonic setting of Taohekou Formation is ocean islands or seamounts, caused by within plate stretching.