简介:Withprocessingandinterpretationof25000kmfull-coveragemultibeamswathdatafromtheeasternSouthChinaSea,itisfoundthatNE-trendingandNW-trendinglinearmorphologicalfeaturessuchasscarps,horstsandgrabens,govemthecentralpart(14°~17°N)ofeasternsubbasin.Comparedwithreflectionseismicprofiles,theseNE-trendinglinearmorpho-structuresareconsideredtobetherepresentationofbasementstructuresonseabedandcanbedividedintothreelinearstructuralzones.ThetrendofthecentralzoneisNE45°~50°occurringaroundextinctspreadingcenter,thetrendofthesecondzoneisNE70°~78°onbothsidesofthecentraloneandthetrendofthethirdzoneisaboutNE60°justonthenorthofthesecondone.ThesethreeNE-trendinglinearzonesareformedinlate-stageNW-SE-trendingseafloorspreadingoftheeasternsubbasinalongNW-trendinglinearfaults,andrespectivelycorrespondtothreespreadingepisodes:17.0~19.0Ma(5d-5e),19.0~21.0Ma(5e-6a)and21.0~24.2Ma(6a-6c)basedonthecontrastofmorpho-structurestomagneticlineationanomalies.