陆上和水下喷发成因火山岩特征及元素地球化学判别——以新疆三塘湖盆地马朗凹陷上石炭统火山岩为例  

Characteristics and element geochemical discrimination of subaerial and subaqueous volcanic rocks:taking the Upper Carboniferous volcanic rocks of Malang Depression in Santanghu Basin in Xinjiang as an example

作　　者：刘德成 陈亚军 伍宏美 马强 张桓 LIU Decheng;CHEN Yajun;WU Hongmei;MA Qiang;ZHANG Huai(School of Engineering and Technology,China University of Geosciences(Beijing),Beijing,100083,China;Beijing Geological and Mineral Exploration and Development Group Company Limited,Beijing,100050,China;Beijing Institute of Geology,Beijing,100011,China;China United Academy of 8etroleum Sciences,Beijing 100101,China;Research Institute of Exploration and Development,Yumen OU field Company,CNPC,J iuquan,Gansu 735019,China;519 Team o f North China Geological Exploration Bureau,Academy of Geological Environment Engineering,Baoding,Hebei 071051,China)

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]北京市地质研究所,北京100011 [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]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：《东北石油大学学报》2021年第6期41-51,79,I0003,I0004,共14页Journal of Northeast Petroleum University

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(DD20190143)。

摘　　要：根据火山喷出物堆积与保存时的古地理环境,可将火山岩划分为陆上沉积火山岩和水下沉积火山岩。为探讨二者在地质特征上的区别及元素地球化学特征上的差异,建立陆上、水下两种火山喷发沉积模式,总结二者在岩性组合与结构构造、共生岩石及化石组合、蚀变与脱玻化、节理与裂缝发育等特征,以及与下伏地层接触关系的区别;利用化学风化指标及火山岩夹持的泥岩微量元素比值等元素地球化学方法,对两种喷发沉积成因环境火山岩进行判别。结果表明:马朗凹陷上石炭统火山岩喷发沉积期的古地理环境复杂,既有陆上与水下喷发沉积成因,又有水—陆交替的过渡相沉积成因,与研究区卡拉岗组火山岩Fe 2O 3与FeO分布特征得出的喷发沉积古环境相符合。该结果为盆地火山岩地层岩石成因环境分析及岩相古地理研究提供依据。According to the ancient geographical environment of volcanic ejecta accumulation and preservation,volcanic rocks can be divided into subaerial and subaqueous eruptive sedimentary origins.In order to discuss their differences in geological and geochemical characteristics of elements,we established two models of subaerial and subaqueous volcanic eruption depositions,summarized the differences between them in lithologic assemblage and structure,symbiotic rock and fossil assemblage,alteration and devitrification,development characteristics of joints and fractures,and contacted their relationship with underlying strata,and distinguished two kinds of volcanic rocks of different eruptive sedimentary origins by means of element geochemistry,such as chemical weathering index and ratio characteristics of mudstone micronutrient sandwiched by volcanic rocks.Studies have shown that the paleogeographic environment of volcanic eruption and sedimentation in Upper Carboniferous of Malang Depression is complex,with subaerial and subaqueous eruption sedimentary origins,and transitional facies sedimentary origin of water-land alternation,consistent with the eruptive sedimentary paleoenvironment based on the Fe2 O3 and FeO distribution characteristics of Kalagang Formation volcanic rocks in study area.This result provides basis for the analysis of petrogenetic environment and lithofacies paleogeography of basin volcanic rock strata.

关 键 词：陆上沉积火山岩 水下沉积火山岩 元素地球化学 卡拉岗组 马朗凹陷 新疆三塘湖盆地 

分 类 号：P595[天文地球—地球化学] TE122[天文地球—地质学]