摘要
海拉尔盆地深层侏罗系含火山岩地层是现今油气勘探重点。笔者以海拉尔盆地嵯岗隆起火山岩为例,通过锆石U-Pb年代学和全岩地球化学研究,确认其形成时代和地层序列,讨论其构造背景,并与盆内深层火山岩地层进行初步对比。根据测年结果和前人研究,将嵯岗隆起侏罗系火山岩划分为2期:中—晚侏罗世塔木兰沟组(168~156 Ma)和晚侏罗世满克头鄂博组(157~144 Ma),分别对应海拉尔盆地盆内塔木兰沟组下段(166~157 Ma)和塔木兰沟组上段(156~148 Ma)。火山岩SiO_(2)含量介于57.73%~71.07%之间,主要为高钾钙碱性岩和钾玄质岩;稀土配分模式呈右倾型,轻重稀土分异明显;酸性火山岩富集大离子亲石元素(K、Rb),亏损高场强元素(Nb、Ta、Ti、P),中基性火山岩富集大离子亲石元素(Ba、K),亏损高场强元素(Nb、Ta、Ti)。综合研究表明,嵯岗隆起火山岩可能形成于后碰撞伸展环境中,与蒙古—鄂霍茨克洋闭合后岩石圈伸展有关。
The Jurassic volcanic bearing strata are main targets for hydrocarbon exploration in deep Hailar Basin.In this paper,zircon U-Pb chronology and whole rock geochemistry on Jurassic volcanic rocks in Cuogang uplift are used to confirm their formation age and stratigraphic sequence,to discuss their tectonic background,and correlate them with volcanic rocks buried in the Hailar Basin.Combining the dating results of this paper with previous studies,the Jurassic volcanic rocks in Cuogang uplift can be divided into two stages:Middle and Late Jurassic Tamulangou Formation(168~156 Ma);Late Jurassic Manketou' ebo Formation(157~144 Ma).It corresponds to the lower member of Tamulangou Formation(166~157 Ma)and the upper member of Tamulangou Formation(156~148 Ma)within Hailar Basin.The SiO_(2) content of volcanic rocks ranges from 57.73%to 71.07%,mainly high potassium calc-alkaline rocks and shoshonitic rocks.The distribution pattern of rare earth element(REE)is right inclined,and the differentiation of light and weight REE is significant.The acidic volcanic rocks contain high LILE(K,Rb),and low HFSE(Nb,Ta,Ti,P).The intermediate-mafic volcanic rocks contain high LILE(Ba,K),and low HFSE(Nb,Ta,Ti).Comprehensive research shows that the Jurassic volcanic rock formed under a post-collision tectonic setting related to the extension of the lithosphere after the closure of the Mongo-Okhotsk Ocean.
作者
程泽宇
边伟华
陈崇阳
杨卓龙
高航
王璞珺
CHENG Zeyu;BIAN Weihua;CHEN Chongyang;YANG Zhuolong;GAO Hang;WANG Pujun(College of Earth Sciences,Jilin University,Changchun 130061,China;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources,Changchun 130026,China;College of Tourism and Geographical Science,Jilin Normal University,Siping 136000,Jilin,China)
出处
《世界地质》
CAS
2022年第3期451-464,共14页
World Geology
基金
国家重点研发计划项目(2019YFC0605402)
国家自然科学基金重大项目(41790453)联合资助。
作者简介
第一作者:程泽宇(1997—),男,硕士研究生,主要从事盆地火山岩及油气地质研究。E-mail:chengzy19@mails.jlu.edu.cn;通信作者:边伟华(1976—),男,副教授,主要从事盆地火山岩及油气地质研究。E-mail:WeihuaBian@jlu.edu.cn。
