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地质学报 2015
TheDeepStructureFeatureoftheSichuanBasinandAdjacentOrogens, PP. 1153-1164 Keywords: Sichuanbasin,basin-rangecontactzone,deepstructure,topinterfaceofbasement,Mohodepth Abstract: Thebasin-mountainsystemintheSichuanBasin(SCB)reflectsthemaintectonicactivityandtheorogenicdenudationinthisregion.Theseismicprobingworkrevealsthedeepstructureofthebasin-mountainsystem.Theseismicworkwasre-sampledtotheMohodepthandthesedimentarythicknessaswellastheP-wavevelocity-depthfunctiontoanalyzethedeepstructureoftheSCBandadjacentorogens.TheresultsshowtwodepositcentersintheSCB:theDeyangareainthewestandtheNanchuanareaintheeastanddepressionupliftexistsinthesouthwesternpartoftheSCB;theMohoshallowersgraduallyfromthewesttoeast(ca.62-36kmdeep),theSouth-Northseismicbelt(SNSB)isverydistinctive:theMohodepthismuchshallower(<50km)totheeastoftheSNSB,whereasitismuchdeeper(>50km)tothewestoftheSNSB,suggestingthattheSNSBratherthantheLongmenShantectonicbeltisamainMohotransitionbelt;thetopographyandthetopinterfaceofthebasementhavethesameundulationtrendwhenthesedimentarythicknessandtheMohodepthhaveamirrorrelationship;thelowvelocityzonedevelopedintheKangdianthrustandfoldbeltandSongpan-Garzêbeltimpliedasoft,weakandthickcrustthereshowingtectonicactivityintheseareas.
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