華北克拉通中部造山帶呂梁群的形成時代與構(gòu)造環(huán)境

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[分類號]P588；P597 [文獻(xiàn)標(biāo)志碼］A

Abstract： The Luliang Group is situated in thecentral part of the Trans-North China Orogen （TNCO），North China Craton.Investigations of the formation age and tectonic seting of the groupare helpful forunderstanding NeoarcheanPaleoproterozoicregional tectonic evolution.Petrography，geochemistry，and zircon U-Pb dating arecombined to study meta-sedimentary and meta-volcanic rocks in the Luliang Group.The findings reveal that the maximum depositional ages of meta-sedimentary rock samplesare ～2510Ma （Yuanjiacun Formation） and ～2443Ma （Peijiazhuang Formation）， while the crystallization ages of meta-volcanic rock samples are ～2369Ma （Jinzhouying Formation） and ～2187Ma （Dujiagou Formation）. These new data， combined with previous geochronological studies，imply that the Luliang Groupcan be separated into lower and upper sections.The Yuanjiacun and Peijiazhuang Formations of the lower part consist of meta-sedimentary rocks，and were mainly deposited in the late Neoarchean to early Paleoproterozoic. The Jinzhouying and Dujagou Formations of the upper part are composed of meta-volcanic rocks，and formed in the mid-Paleoproterozoic.Geochemical data show that the meta-sedimentary rocks inthe Luliang Group may have been sourced from acidic magmatic rocks in an active continental margin， while the protoliths of the metamorphic mafic volcanic rocks are likely arc volcanic rocks.Thus，the Luliang Group may haveformed inan activecontinental margin.TheLuliang Group issimilar in age to the lateNeoarchean to midPaleoproterozoic arc-related magmatic rocks in the Luliang-Yunzhongshan area and the TNCO，indicating that the orogen may have originally been a long-lived magmatic arc.

Key Words：Neoarchean-Paleoproterozoic； active continental margin；Luliang Group；North China Craton;Zircon U-Pb dating

華北克拉通是世界上最古老的克拉通之一，廣泛出露太古宙至元古宙巖石（Zhaietal.，2005;Zhaoetal.，2005）。（剩余39388字）