海南岛北部更新世火山岩地层新知  

A NEW APPROACH OF THE PLEISTOCENE VOLCANIC ROCK STRATA IN THE NORTHERN HAINAN ISLAND

作　　者：周进波 王永红[2] 文健 ZHOU Jin Bo;WANG Yong Hong;WEN Jian(Hainan Key Laboratory of Marine Geological Resources and Environment,Haikou 570206;Hainan Geological Survey Institute,Haikou 570206)

机构地区：[1]海南省海洋地质资源与环境重点实验室,海南海口570206 [2]海南省地质调查院,海南海口570206

出　　处：《地层学杂志》2024年第2期210-217,共8页Journal of Stratigraphy

基　　金：海南省海洋地质资源与环境重点实验室开放课题(HNHYDZZYHJKF002);中国地质调查局项目(DD20160035-10、DD20190304)共同资助。

摘　　要：准确划分琼北地区更新世火山岩地层层序对于琼北断陷盆地发展演化研究和工程地质勘察具有重要意义。本文通过大量第四纪火山岩陡坎野外调查,结合钻孔资料和新的年代学数据,发现以往对更新世火山岩的岩性组合和岩石地层单位的划分依据存在不合理性,并根据新的资料对更新世火山岩的岩石地层划分方案进行了调整。更新世火山岩岩性组合为玄武岩-火山碎屑岩-玄武岩,老城镇—石山镇一带的火山碎屑岩被红土化层分为两部分,下部属更新世,上部属全新世。红土化层光释光年代学结果主要集中在15.9±0.9ka与35.2±1.9ka之间,限定了红土化层形成在晚更新世,其层位位于全新世火山碎屑岩之下,而不是更新世玄武岩与更新世火山碎屑岩之间。更新世多文组失去了地质依据,建议废除。本文根据岩性组合特征及测年结果,建议将更新世火山岩重新厘定为新的道堂组,并分为上、中、下三段,时代为晚更新世。To accurately delineate the stratigraphic sequence of the Pleistocene volcanic rocks in the Qiongbei fault basin in the northern margin of Hainan Island,South China,the stratigraphy and chronology of the volcanic rocks were studied,which is important for engineering geological exploration.Field work,borehole study,and age dating were conducted,based on which the scheme of lithostratigraphic division of the volcanic rocks were revised.The Pleistocene volcanic rocks are composed of two basalt units intercalated by a pyroclastic rock unit.The pyroclastic rocks in Laocheng−Shishan area can be divided into a lower Pleistocene part and an upper Holocene part.The data of OSL dating of red soil(laterite)range from 15.9±0.9 to 35.2±1.9 ka,which constrained the age of the red soil to the Late Pleistocene,and its position should be below the Holocene pyroclastic rocks,rather than between the Pleistocene basalts and Pleistocene pyroclastic rocks.Therefore,the Pleistocene Duowen Formation lost its geological basis and is recommended to be abolished.Based on the lithostratigraphic characteristics and dating results,the Pleistocene volcanic rocks were redefined as the new Daotang Formation consisting of upper,middle and bottom members and being formed in the Late Pleistocene.

关 键 词：道堂组 多文组 更新世 火山岩 海南岛 

分 类 号：P534.63[天文地球—第四纪地质学]