新疆乌苏泥火山地球化学特征及其泥浆源  

Geochemical characteristics of Wusu mud volcanoes in Xinjiang and their mud sources

作　　者：樊海龙[1,2,3] 彭传凯 余心起[3] 陈晶源[3] 李江涛[5] 乔东海[3] 郭建明[1] 许世阳 FAN Hailong;PENG Chuankai;YU Xinqi;CHEN Jingyuan;LI Jiangtao;QIAO Donghai;GUO Jianming;XU Shiyang(Key Laboratory of Petroleum Resources,Gansu Province/Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China;University of Chinese Academy of Sciences, Beijing 100049, China;School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;No. 7 Geological Party, BGMERD of Xinjiang, Wusu 833000, Xinjiang, China;No. 8 Geological Party, BGMERD of Xinjiang, Akesu 843000, Xinjiang, China)

机构地区：[1]甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049 [3]中国地质大学(北京)地球科学与资源学院,北京100083 [4]新疆维吾尔自治区地质矿产勘查开发局第七地质大队,新疆乌苏833000 [5]新疆维吾尔自治区地质矿产勘查开发局第八地质大队,新疆阿克苏843000

出　　处：《地质通报》2017年第8期1428-1438,共11页Geological Bulletin of China

基　　金：中国地质调查局项目<天山成矿带境内外构造背景与成矿环境对比研究>(编号:12120114006201)

摘　　要：泥火山是地质流体活动的结果,喷发需具备泥浆源、泥浆运移通道和水补给3个条件。对乌苏泥火山8个喷口泥浆进行岩石地球化学分析,轻稀土元素富集,重稀土元素亏损,轻、重稀土元素平均比值为6.81,泥浆中富集大离子亲石元素Ba、Rb等,高场强元素Nb、Ta强烈亏损,Th弱亏损,(La/Yb)_N值为5.47,Ce/La值为2.22,球粒陨石标准异常值δEu显示中等负异常(0.760~0.805);Sr/Ba值为0.33~1.01(平均值0.60),表明源岩为陆相沉积且古盐度较低,Ce/La(2.22)、Ce_(anom)(-0.007)、V/(V+Ni)(0.78)值均指示源岩形成于还原环境。稀土、微量元素分析及地层对比分析表明,乌苏泥火山源岩来自于下侏罗统八道湾组、三工河组,为河流沼泽相-半深湖相含煤地层代表的弱还原-还原沉积环境,源岩的最大埋藏深度为7~8km。泥火山源岩的研究为指示油页岩、烃类物质的位置提供了证据。The mud volcano results from magmatic eruption formed by geological fluid activity.The formation of mud volcano requires three conditions,i.e.,mud source,mud migration channel and water supply.Geochemical data of8samples from Wusu mud volcanoes are characterized by enrichment of LREEs relative to HREEs.Chondrite standard abnormalδEu values are0.760~0.805,(La/Yb)N is5.47,and Ce/La is2.22.The mud is enriched in large ion stone elements(LILE)such as Ba and Rb,whereas the high field strength elements(HFSE)Nb,Ta are strongly depleted.Sr/Ba ratios(0.33~1.01)suggest a lower paleo-salinity,Ce/La(2.22),Ceanom(-0.007),and V/(V+Ni)(0.78)ratios indicate that the source rocks were formed in a reducing environment.REE and trace elements analyse show that the source rocks of Wusu mud volcanoes were derived from lower Jurassic Dadaowan Formation and San gonghe Formation,suggesting a river swamp-semi-deep lake sedimentary facies of coal-bearing strata which represent a kind of weak reducing environment.The mud volcano geochemical data and stratigraphic section of Wusu imply that the maximum depth of mud source strata is about7~8km.

关 键 词：泥火山 地球化学 侏罗纪 页岩 源岩地层 还原环境 新疆乌苏 

分 类 号：P595[天文地球—地球化学] P588.11[天文地球—地质学]