北部湾涠洲岛及斜阳岛火山地质与喷发历史研究  

Geology and eruption history of volcanoes in Weizhou Island and Xieyang Island,Northern Bay.

作　　者：樊祺诚[1] 孙谦[1] 龙安明 尹克坚 隋建立[3] 李霓[1] 王团华[1] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]广西地震局,南宁530022 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》2006年第6期1529-1537,共9页Acta Petrologica Sinica

基　　金：国家自然科学基金(No.40572044);广西科学研究与技术开发项目(No.0322022-1)共同资助

摘　　要：涠洲岛及斜阳岛是北部湾内一对姊妹火山岛,本文采用火山岩K-Ar法,火山岩中砂岩捕掳体光释光法(OSL)和贝壳^(14)C法分别测定了火山活动的年代,结合火山岩地质特征,将涠洲岛火山活动初步划分为早-中更新世(1．42Ma～0．49Ma)和晚更新世末期(36ka～33ka)两期。早-中更新世溢流玄武质熔岩盾造就了涠洲岛及斜阳岛,从涠洲岛横路山锅盖岭盾形火山锥溢出的熔岩流向四周漫流,形成涠洲岛中心高四周低的盾形火山地形,其晚阶段球状风化玄武岩沿涠洲岛潮间带分布。晚更新世末期涠洲岛南湾火山和斜阳岛斜阳村火山射气岩浆喷发,间有岩浆喷发,形成典型的低平火山口和巨厚基浪堆积几乎覆盖两岛,经历了海蚀作用,塑造了两岛现代地貌景观。The Weizhou Island and the Xieyang Island are twin islands of volcanoes in the Northern Bay. In this paper, volcanic activity on the two islands was analyzed by K-Ar dating of volcanic rocks OSL dating of sandstone xenoliths in the volcanic rocks and ^14C dating of conch by Accelerator Mass Spectrometer respectively. With the geological characteristics of the volcanic rocks, the volcanic activity was divided into two stages, the early stage in the early and middle Pleistocene （ 1.42Ma-0.49Ma） and the late stage at the end of the late Pleistocene （36ka-33ka）. Flood basaltic shield of the early and middle Pleistocene formed the Weizhou Island and Xieyang Island. In the Weizhou Island, lavas from the Henglushan Guogailing shield volcanic center flooded around the island, and formed the shield like shape of the island. Volcanic rocks of the late stage occurred in the tidal zone, and formed typical spherical weathering. In the late Pleistocene, phreatomagmatic eruptions dominated the two islands, with few magmatic eruptions. The phreatomagmatic eruptions formed typical maars and very thick base surge deposits, which almost covered the whole surface of these two islands. It formed the rich characteristics of modem geography after long time of marine abrasion.

关 键 词：北部湾 涠洲岛及斜阳岛 火山地质 喷发特征 喷发历史 

分 类 号：P588.145[天文地球—岩石学] P597.3[天文地球—地质学]