Geochemistry and geochronology of the Delinggou Intrusion: Implications for the subduction of the Paleo-Asian Ocean beneath the North China Craton

详细信息    查看官网全文

• 英文论文题名：Geochemistry and geochronology of the Delinggou Intrusion: Implications for the subduction of the Paleo-Asian Ocean beneath the North China Craton
• 论文作者：陳卉君 ; 趙國春 ; 江博明
• 英文论文作者：Department of Earth Sciences ; University of Hong Kong ; Department of Geosciences ; National Taiwan University
• 年：2016
• 作者机构：Department of Earth Sciences,University of Hong Kong;Department of Geosciences,National Taiwan University;
• 英文论文关键词：Central Asian Orogenic Belt ; continental margin arc ; diorite ; Paleo-Asian Ocean ; subduction ; North China Craton
• 会议召开时间：2016-10-15
• 会议录名称：2016中国地球科学联合学术年会论文集（七）——专题15：中央造山系构造演化、专题16：华南大陆构造、专题17：中亚造山带与成矿
• 语种：英文
• 分类号：P542;P597.3
• 学会代码：ZGDW
• 会议名称：2016中国地球科学联合学术年会
• 会议地点：中国北京
• 主办单位：中国地球物理学会、中国地震学会、全国岩石学与地球动力学研讨会组委会、中国地质学会构造地质学与地球动力学专业委员会、中国地质学会区域地质与成矿专业委员会
• 学会名称：中国地球物理学会
• 页数：1
• 文件大小：904k
• 原文格式：D
• 会议级别：全国

摘要

The Paleo-Asian Ocean was a Neoproterozoic to Paleozoic ocean located between Tarim-North China and East Europe-Siberia,whose opening was related to the breakup of the Rodinia supercontinent and whose expansion and closure led to the formation of the Central Asian Orogenic Belt(CAOB)and collision of TarimNorth China and East Europe-Siberia.However,there is a hot debate on the issue of whether or not the PaleoAsian Ocean had experienced southward subduction beneath the North China Craton before its closure and when the southward subduction initially started if such subduction did happen.To resolve this issue,we carried out an integrated petrological,geochemical and geochronological study on the Delinggou intrusion in the Siziwangqi area(central Inner Mongolia),which is situated at the northern margin of the North China Craton.The Delinggou intrusion consists predominantly of diorite and quartz diorite,with minor gabbroic diorite.LA-ICP-MS U-Pb zircon dating results indicate that these rocks were emplaced during early Carboniferous time from 330 to 343 Ma.Geochemically,the rocks from the Delinggou intrusion belong to the calc-alkaline and metaluminous type,and are enriched in large ion lithophile elements(LILE,e.g.,Rb,Sr and Ba),but depleted in high field strength elements(HFSE,e.g.,Zr,Nb,Hf,Ta and Ti),characterizing magmatic arc rocks.On the basis of these geochemical features,the Delinggou intrusion is interpreted to have resulted from the partial melting of an enriched subcontinental lithospheric mantle contaminated by ancient lower crustal material in a continental margin arc setting.Accordingly,the results of this study confirm that the Paleo-Asian Ocean did undergo southward subduction beneath the North China Craton,which started in the Carboniferous(343-330 Ma),not in the Devonian as previously considered.
The Paleo-Asian Ocean was a Neoproterozoic to Paleozoic ocean located between Tarim-North China and East Europe-Siberia, whose opening was related to the breakup of the Rodinia supercontinent and whose expansion and closure led to the formation of the Central Asian Orogenic Belt(CAOB) and collision of TarimNorth China and East Europe-Siberia. However, there is a hot debate on the issue of whether or not the PaleoAsian Ocean had experienced southward subduction beneath the North China Craton before its closure and when the southward subduction initially started if such subduction did happen. To resolve this issue, we carried out an integrated petrological, geochemical and geochronological study on the Delinggou intrusion in the Siziwangqi area(central Inner Mongolia), which is situated at the northern margin of the North China Craton. The Delinggou intrusion consists predominantly of diorite and quartz diorite, with minor gabbroic diorite. LA-ICP-MS U-Pb zircon dating results indicate that these rocks were emplaced during early Carboniferous time from 330 to 343 Ma. Geochemically, the rocks from the Delinggou intrusion belong to the calc-alkaline and metaluminous type, and are enriched in large ion lithophile elements(LILE, e.g., Rb, Sr and Ba), but depleted in high field strength elements(HFSE, e.g., Zr, Nb, Hf, Ta and Ti), characterizing magmatic arc rocks. On the basis of these geochemical features, the Delinggou intrusion is interpreted to have resulted from the partial melting of an enriched subcontinental lithospheric mantle contaminated by ancient lower crustal material in a continental margin arc setting. Accordingly, the results of this study confirm that the Paleo-Asian Ocean did undergo southward subduction beneath the North China Craton, which started in the Carboniferous(343-330 Ma), not in the Devonian as previously considered.

引文

Jahn,B.M.,2004.The Central Asian Orogenic Belt and growth of the continental crust in the Phanerozoic.Geological Society,London,Special Publications 226,73-100.
    Seng?r,A.,Natal'In,B.,Burtman,V.,1993.Evolution of the Altaid tectonic collage and Palaeozoic crustal growth in Eurasia.Nature 364,299-307.
    Windley,B.F.,Alexeiev,D.,Xiao,W.,Kr?ner,A.,Badarch,G.,2007.Tectonic models for accretion of the Central Asian Orogenic Belt.Journal of the Geological Society 164,31-47.
    Xiao,W.J.,Windley,B.F.,Hao,J.,Zhai,M.,2003.Accretion leading to collision and the Permian Solonker suture,Inner Mongolia,China:termination of the central Asian orogenic belt.Tectonics 22.
    Zhang,S.H.,Zhao,Y.,Ye,H.,Liu,J.M.,Hu,Z.C.,2014a.Origin and evolution of the Bainaimiao arc belt:implications for crustal growth in the southern central Asian orogenic belt.Geological Society of America Bulletin 126,1275-1300.