火山岩陆上与水下喷发沉积环境的地球化学判识方法研究  

Geochemistry discriminance study of subaerial and underwater eruptive depositional environment of volcanic rocks

作　　者：刘德成 陈亚军 伍宏美 马强 何兴华 张桓 Liu Decheng;Chen Yajun;Wu Hongmei;Ma Qiang;He Xinghua;Zhang Huan(School of Engineering and Technology,China University of Geosciences(Beijing),Beijing 100083;Beijing Geology and Mineral Exploration and Developing Group Co.,Ltd,Beijing 100050;Beijing Institute of Geological Hazard Prevention,Beijing 100120;China United Academy of Petroleum Sciences,Beijing 100101;Research Institute of Exploration and Development,Yumen Oilfield Company,PetroChina,Jiuquan,Gansu 735019;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081;University of Chinese Academy of Sciences,Beijing 100049;Academy of Geological Environment Engineering,519 Team of North China Geological xploration Bureau,Baoding,Hebei 071051)

机构地区：[1]中国地质大学(北京)工程技术学院,北京100083 [2]北京市地质矿产勘查开发集团有限公司,北京100050 [3]北京市地质灾害防治研究所,北京100120 [4]北京中科联华石油科学研究院,北京100101 [5]中国石油玉门油田分公司勘探开发研究院,甘肃酒泉735019 [6]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵阳550081 [7]中国科学院大学,北京100049 [8]华北地质勘查局五一九大队地质环境工程院,河北保定071051

出　　处：《地质科学》2022年第3期809-834,共26页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：中国地质调查局西安地质调查中心综合地质调查项目(编号:DD20190143)资助。

摘　　要：陆上、水下两种不同喷发沉积环境火山岩储层特征差异明显,准确判识火山喷发沉积环境是火山岩储层评价的重要依据。研究使用Fe_(2)O_(3)/(Fe_(2)O_(3)+FeO)作为火山岩氧化系数,并充分考虑火山喷发期的地理环境、岩浆性质(岩石酸度)、构造成因环境、流体活动、风化淋溶作用、成岩后表生作用等影响因素,针对不同影响因素提出校正方法和合理的规避思路;建立及改进了基于火山岩氧化系数的喷发沉积环境判别图,得出消减带火山岩(活动陆缘和岛弧火山岩)陆上与水下喷发沉积环境的氧化系数判别标准。运用改进的图版及标准,对新疆三塘湖盆地马朗凹陷上石炭统卡拉岗组(C_(2)k)火山岩喷发沉积环境进行判识,结果表明,39件火山岩样品主要为陆上喷发沉积火山岩和水、陆过渡复杂环境沉积成因的火山岩。实际应用结果与前人基于卡拉岗组火山岩共生岩石与化石组合、风化壳、示底构造等典型标志得到的结果相符合;基于多因素分析法筛选样品,建立改进的判别图对喷发环境的指示意义具有普遍适用性,不受地质时代及区域地质条件的限制。There are obvious differences in volcanic reservoir characteristics between onshore and underwater eruptive sedimentary environments.Accurate identification of volcanic eruptive sedimentary environment is an important basis for volcanic reservoir evaluation.In this study,Fe_(2)O_(3)/(Fe_(2)O_(3)+FeO)ratio is used as the oxidation coefficient of volcanic rocks,and the influence factors such as rock acidity,tectonic genetic environment,weathering and leaching,alteration and metasomatism are fully considered.This paper establishes and improves the discrimination chart of eruptive sedimentary environment based on the oxidation coefficient of volcanic rocks,and obtains the discrimination standard of oxidation coefficient of volcanic rocks(active continental margin and island arc volcanic rocks)on land and underwater eruptive sedimentary environment in the subduction zone of block B.Based on the improved chart and standard,the volcanic eruption environment of the upper Carboniferous karagang formation(C_(2)k)in Malang Sag,Santanghu Basin,Xinjiang was identified.The results show that 39 volcanic samples are mainly continental eruptive sedimentary volcanic rocks and volcanic rocks originated from the complex environment of water land transition.The practical application results are consistent with those obtained by zhuka et al.Based on typical indicators such as paragenetic rocks and fossil assemblages,weathering crust and bottom showing structure of karagang Formation volcanic rocks.The improved discriminant map based on factor analysis method has universal significance in indicating eruption environment,and is not limited by geological age and regional geological conditions.

关 键 词：火山岩 喷发沉积环境 氧化系数 马朗凹陷 卡拉岗组 

分 类 号：P581[天文地球—岩石学]