Crust and upper mantle structures beneath Northeast China from receiver function studies

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摘要 P-waveandS-wavereceiverfunctionanalyseshavebeenperformedalongaprofileconsistedof27broadbandseismicstationstoimagethecrustalanduppermantlediscontinuitiesacrossNortheastChina.TheresultsshowthattheaverageMohodepthvariesfromabout37kmbeneaththeDaxing’anlingorogenicbeltinthewesttoabout33kmbeneaththeSongliaoBasin,andtoabout35kmbeneaththeChangbaimountainregionintheeast.OurresultsrevealthattheMohoisgenerallyflatbeneaththeDaxing’anlingregionandaremarkableMohooffset(about4km)existsbeneaththebasin-mountainboundary,theDaxing’anling-TaihangGravityLine.BeneaththeTanlufaultszone,whichseperatestheSongliaoBasinandChangbairegion,theMohoisupliftandthecrustalthicknesschangesrapidly.WeinterpretthisfeatureasthattheTanlufaultsmightdeeplypenetrateintotheuppermantle,andfacilitatethemantleupwellingalongthefaultsduringtheCenozoicera.Theaveragedepthofthelithosphereasthenosphereboundary(LAB)is*80kmalongtheprofilewhichisthinnerthananaveragethicknessofacontinentallithosphere.TheLABshowsanarc-likeshapeinthebasin,withtheshallowestpartapproximatelybeneaththecenterofthebasin.TheupliftLABbeneaththebasinmightberelatedtotheextensivelithosphericstretchingintheMesozoic.Inthemantletransitionzone,astructurallycomplicated660kmdiscontinuitywithamaximum35kmdepressionbeneaththeChangbairegionisobserved.The35kmdepressionisroughlycoincidentwiththelocationofthestagnantwesternpacificslabontopofthe660kmdiscontinuityrevealedbytherecentPwavetomography.
机构地区 不详
出处 《地震学报:英文版》 2014年3期
出版日期 2014年03月13日(中国期刊网平台首次上网日期,不代表论文的发表时间)