今天是2018年01月17日

大兴安岭中段晚三叠世哈达陶勒盖组火山岩 成因及构造背景

DOI:10.3799/dqkx.2017.138

作者:马永非,刘永江,温泉波,张志斌,李伟,司秋亮,唐振

联系地址:吉林大学地球科学学院,吉林长春 130061

摘要:为了解大兴安岭中段晚三叠世时期的构造背景,对该时期哈达陶勒盖组火山岩进行了岩石学、锆石U-Pb年代学及地球化学等方面的研究.哈达陶勒盖组火山岩可划分为中性系列安粗岩、安山岩,中酸性系列石英粗安岩及酸性系列流纹岩,形成年龄分别为:210.9±3.5Ma、216.6±3.1Ma、216.9±2.1Ma和230.2±2.2Ma.中性系列岩浆来源于原始地幔的部分熔融,并遭受俯冲板片释放流体的强烈富集作用.岩浆演化过程中结晶分异作用不明显,但遭受较强的地壳混染.中酸性系列和酸性系列岩浆来源于相对较浅的地壳物质深熔,前者岩浆演化过程中结晶分异作用较弱,而后者则较强.大兴安岭中段晚三叠世时期的构造演化背景受蒙古-鄂霍茨克洋板块向南俯冲作用的影响明显,在研究区表现为弧后伸展的构造背景.俯冲板片的断离拆沉引起了软流圈物质上涌,并导致伸展构造背景的形成,也为哈达陶勒盖组火山岩原始岩浆的形成提供了热量来源.

关键字:大兴安岭中段;晚三叠世火山岩;哈达陶勒盖组;锆石U-Pb年代学;地球化学;构造学.

Petrogenesis and Tectonic Settings of Volcanic Rocks from Late Triassic Hadataolegai Fm. at Central Part of Great Xingan Range

Author:Ma Yongfei,Liu YongjiangWen Quanbo,Zhang Zhibin,Li Wei,Si Qiuliang,Tang Zhen

Author Address:College of Earth Sciences, Jilin University, Changchun 130061, China

Abstract:To realize the tectonic setting at central part of Great Xingan Range during Late Triassic, petrology, zircon U-Pb chronology and geochemical of the Late Triassic Hadataolegai Fm. were analyzed in this paper. The volcanic rocks from Late Triassic Hadataolegai Fm. can be divided into three rock series which are intermediate latite and andesite,intermediate to acidic quartz trachyandensite and acid rhyolite,and their formation ages are 210.9±3.5Ma,216.6±3.1Ma,216.9±2.1Ma and 230.2±2.2Ma,respectively.The magma of intermediate series was derived from partial melting of lithospheric mantle which fully enriched by fluids released from subduction oceanic lithosphere.There have no or slightly crystallization fractionation but suffered seriously crustal contamination during magma upwelling.Intermediate to acidic and acidic series rocks have crustal-derived magma source features, the crystallization fractionation of intermediate to acidic magma was unconspicuous during its evolution course, but it was quite obvious to the acidic series.The southward subduction of the Okhotsk oceanic lithosphere has played an important role to the tectonic setting at central part of Great Xingan Range during Late Triassic, and appear back-arc extension signiture at the study area.This extension background leaded by asthenosphere magma upwelling which caused by subduction oceanic lithosphere delamination,and the asthenosphere magma upwelling provides energy to the primary magma generation for volcanic rocks of the Late Triassic Hadataolegai Fm. meanwhile.

Keyword:central part of Great Xingan Range; Late Triassic volcanic rock; Hadataolegai Fm.; zircon U-Pb geochronology; geochemistry; tectonics.

 

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作者简介:马永非(1986-),男,博士研究生,主要从事构造地质研究.ORCID:0000-0003-0740-0472.E-mail:510364094@qq.com

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