Tectonic Evolution Of The Jiamusi Massif: Constrains From Late Paleozoic Sedimentary-volcanic Rocks

NE China and adjacent regions, including the Russian Far East, havetraditionally been considered as the eastern part of the Central Asian Orogenic Belt,located between the Siberia and North China cratons. This region was not onlyaffected by the closing of Paleo-Asian Ocean, but also influenced by the subsequentoverprint and reconstruction related to the Pacific subduction. NE China is consideredto consist of a collage of micro-continental blocks, The Jiamusi Massif, located ateastern of CAOB, is significant for understanding tectonics and evolution of theCentral Asian Orogenic Belt.Late Paleozoic stata was widespread distributed in eastern margins of the JiamusiMassif, but its chronology and tectonic affinity is controversy. The current study ismainly focusing on the Devonian and Carboniferous sandstones and Permian basalticandesite exposed in Baoqing area, Jiamusi Massif, the systemically sandstone detritalclasts component analysis, geochemistry and LA-ICP-MS U-Pb detrital zircon ageshave been carried out on the studied Formatiom, The result presented in this papersuggests late Paleozoic tectonic evolution of Jiamusi Massif and tectonic history ofNE China.Baoqing area geographically exposed in eastern of Jiamusi Massif. that isbounded by the Nadanhada Terrane to the east, truncated by the Mudanjiang suturezone in the southwest, and by the Solonker-Xar Moron-Changchun suture zone in thesouth, where late Paleozoic strata are widespread. The sediments of the Devonian Heitai Formation and Carboniferous Zhenzishan Formation are mostly classified asfeldsparthic litharenite, which consists mainly of quartz, lithic clasts, feldspar andmicas, with a small amount of accessory minerals. The lithic clasts are predominatelycharacterized by the volcanic lithic grains. Additionally, the monocrystalline quartzgrains are extremely high in the framework of total quartz grains. The detritalcompositions indicate that the sandstones are immature, probably due to the effects ofrapid erosion, transport, and diagenetic process and/or nearly supplying derived fromthe source. In addition, the detrital modal analysis applying the Dickinson’s trianglediagrams also indicate the sediments of Heitai Formation are mainly derived fromrecycled orogenic and Cration interior source, while the sediments of ZhenzishanFormation are mostly derived from recycled orogenic and dissected arc source.The major elements and their radios （especially, Fe₂O₃/K₂O and Na₂O/K₂O） areclosely associated with arkose and greywacke for the sandstone from HeitaiFormation and wacke and greywacke for the sandstone from Zhenzishan Formation.Trace elements in the studied sandstones from the two formations mentioned aboveare upper crust-normalized patterns, and show the similar trends in the spider diagram,suggesting the similar provenances related to the rocks of upper crust. The rare earthelements and their chondrite-normalized patterns in the investigated sandstonesmostly show the LREE content enrichment and negative Eu abnormality, withΣLREE/ΣHREE=5.91⁷.95,（La/Yb）_N＝4.67⁷.80, δEu＝0.59⁰.69in HeitaiFormation and ΣLREE/ΣHREE=6.54⁹.51,（La/Yb）_N＝5.19⁹.16, δEu＝0.69⁰.87in Zhenzishan Formation, revealing that the similar provenances derived from thefelsic upper continent crustal rocks are reasonable to supplying for the sediments ofboth the Heitai and Zhenzishan formations.The indexes of paleo-weathering and chemical alteration （CIA and CIW values）together with the A-CN-K projections have been widely investigated in the sandstonefrom two formations, and show medium source weathering and potassiummetasomatism in the Heitai and Zhenzishan Formations. The geochemicaldiscrimination diagrams exhibit that tectonic setting corresponded for the provenance of the Heitai sediments is characterized by PM and subsequently transferred to theACM, whereas the tectonic setting of provenance of the Zhenzishan sediments tendsto transfer progressively from ACM to CIA.The Permian volcanic rocks in the Erlongshan Formation are mainly composedof basaltic andesite and andesite. They are characterized by low SiO₂contents（54.7%～57.46%）, high Al （15.96%～17.83%） and Mg^#（44～48）, enrichment in Na（Na₂O/K₂O=1.81～3.53）. They belong to subalkaline series and show a calc-alkalineevolutionary trend, most of them are plotted within （medium-K） calc-alkaline series.On the primitive mantle-normalized spider diagram, the Permian volcanic rocks arecharacterized by enrichment in large ion lithophile elements （LILE） and relativelydepletion in high field strength elements （HFSE）. The Chondrite-normalized REEpattern for the Permian volcanic rocks shows that The volcanic rocks arecharacterized by enrichment in light rare earth elements （LREE）, relatively depletionin heavy rare earth elements （HREE）, and no Eu anomalies,（La/Yb）_N=5.0～7.1,δEu=0.87～1.02. The characteristic of petrology and geochemistry imply that mineralfractional crystallization is the dominant mechanism to control magmatic evolution.Besides, the Erlongshan Formation volcanic rocks could be derived from the partialmelting of the lithosphere mantle wedge modified by the subducted oceanic slabunder the tectonic setting of the active continental margin.LA-ICP-MS zircon U-Pb dating results indicate that the maximum age ofdeposition of the Heitai Formation sandstone was younger than～374Ma in the lateDevonian, with a peak age at～380Ma、～406Ma、～476Ma、～509Ma in agepopulations. the maximum age of deposition of the Zhenzishan Formation sandstonewas younger than³13Ma in the late Carboniferous, with a peak age at～315Ma inage populations. the Erlongshan Formation volcanic rocks formed at278Ma in theearly Permian, with a peak age at～280Ma、～370Ma、～509Ma in age populations.Zircon U-Pb date of the Heitai, Zhenzishan and Erlongshan Formations exhibitthat the existence of the Early Paleozoic tectonic-magmatic event within421Ma～542Ma, which is consistent with the ages of the gneissic granites in the Jiamusi Massif and the Caledonian alkali-feldspar granites in the Baoqing area. This magmatic eventcan be also found in the basement of the Songliao Basin and the northeastern XiaoHinggan Mountains. Zircon ages of1035Ma,1466Ma,～1800Ma,～2700Ma,2822Ma, together with other studies, indicate that the Mesoarchean to Neoproterozoicbasement exist in Jiamusi Massif. The provenances of the Heitai and ZhenzishanFormations are derived from Jiamusi Massif.We have proposed a tentative model of tectonic evolution, whereby the blocks ofNE China （including Erguna, Xing’an, Songliao, Jiamusi, Khanka, and Bureya）originated as part of the Late Pan-African （⁵00Ma） orogenic belt developed aroundthe southern margin of the Siberia Craton. The early stage of arc-continent collisionwithin the CAOB was accompanied by reworking of juvenile crust at450-475Ma,leading to melting of thickened lithosphere and intrusion of syn-tectonic granitoids.However, at450-420Ma, during the opening of the Mongol-Okhotsk Ocean, Jiamusiblock rifted away the combined NE China blocks. at420-250Ma, The Jiamusi blockand the combined NE China blocks moved farther south into what is now NE China,probably. Devonian tectonic setting is PM, Carboniferous tectonic transfer from PMto ACM, Permian volcanic distributed widely due to the subduction of the PPC. Thefinal collision between the North China and Siberia cratons occurred at²30Ma in theMiddle Triassic. However, the Jiamusi-Khanka block rifted away at²60Ma in theLate Permian. Final re-docking with the Songliao Block occurred between210and...