简介：ThePayangazucomplexinthecentralMyanmariscomposedmainlyofquartzdiorite,granodiorite,andsomesynplutonicmaficdikes.ThequartzdioriteandgranodioritehavezirconU-Pbagesof130.5±4.0(MSWD=3.5)and118.4±2.5Ma(MSWD=2.4),respectively.Rocksamplesofthequartzdioriteandgranodioritearemetaluminous,enrichedinlarge-ionlithophileelementslikeLREE,Rb,Th,andU,anddepletedinhighfield-strengthelementssuchasHREE,Nb,Ta,P,andTi,indicativeofarc-typemagmaticaffinities.WholerocksamplesofthequartzdioritehaveεHf(t)valueof+0.6,initial^87Sr/^86Srratiosof0.7086to0.7100,andεNd(t)valuesof-4.8to-4.9;whereasrocksofthegranodioritearerelativelyisotopicallyenriched,withεHf(t)valuesof-5.1to-7.2,initial^87Sr/^86Srratiosof0.7117to0.7118,andεNd(t)valuesof-8.7to-8.8.TheisotopicdatatogetherwiththehighMg#(boththequartzdioriteandgranodioritehaveMg#valuesof>40)suggestastronginvolvementofmantlematerialsinthegenesisoftheparentmagmas.Thepossiblepetrogeneticprocessmaybethattheascendingofmeltsfrompartialmeltingofmetasomatizedmantlewedgetriggeredbydehydrationofsubductedslabresultedinpartialmeltingofthelowercrustandmixedwiththelatter.TheseEarlyCretaceousintrusionsfromthecomplexareolderthanthosefoundintheeasternWuntho-PopaarcinwesternMyanmar,easternHimalaya,andwesternYunnanwhichareinterpretedtoberelatedtotheNeo-Tethyansubduction,andhaveεNd(t),εHf(t)valueslowerthanthelatter.Onthecontrary,theagesandgeochemicalcharacteristicsofthePayangazucomplexareconsistentwithsomeoftheintrusionsinthenorthernmagmaticbeltinTibet,easternHimalaya,andwesternYunnanwhicharebelievedtobeassociatedwiththesubductionoftheBangong-NujiangOceancrust.Thus,weproposethattheEarlyCretaceousintrusionsinthecentralMyanmararemostlikelyrelatedtothesouthwardsubductionofanoceanslabthatwaspossiblyanextensionoftheBangong-NujiangOcean.

简介：InsouthernChina,collapsinggullyerosionproducesmassivedepositsofsedimentontheploughlayerofalluvialfanfarmland,leadingtoreducednutrients,increasederodibility,andevendesertification.Theaimofthisstudywastoinvestigatesoilerodibility(thefactorKintheUniversalSoilLossEquation,USLE)andphysicochemicalpropertiesofthealluvialfansofthemostseverecollapsinggullyerosionareas(Hubei,Jiangxi,Fujian,andGuangdongprovinces)insouthernChina.Thesoilsofthecollapsinggullyalluvialfanshadahigherbulkdensity,butalowertotalporosity,saturatedwatercontent,andsiltandclayfractionsthanthecontrol(CK)soilsfromthefarmlandwithoutdesertification.Soilqualitygraduallydecreasedfromfanedgetofanhead.SignificantdecreaseswerefoundinsoilpH,organicmatter,cationexchangecapacity,andtotalpotassium,nitrogen,andphosphorus,aswellasavailablenitrogen,phosphorus,andpotassium,resultinginagradualdecreaseinsoilnutrientsfromthefanedgetothefanhead.Soilerodibilitywasgreatestinthefanhead,andsoilerodibilityKvaluesofthealluvialfanswere53.71%,66.28%,67.53%,and71.68%greaterthanthatinthoseoftheCKsoilsofHubei,Jiangxi,Fujian,andGuangdong,respectively,indicatingasignificantcorrelationbetweenthesoilerodibilityKvaluesandphysicochemicalproperties,particularlysandfractionandorganicmattercontent.Theresultsprovidenewinsightsintotherelationshipbetweensoilphysicochemicalpropertiesanderodibilityofalluvialfans,andsuggestthatimprovingsoilstructuremightincreasesoilfertilityinthecollapsinggullyalluvialfanfarmland.

简介：Weanalyzed360permanentandcampaignGPSdatafrom1999to2017inthesouthernSichuan-Yunanblock,andobtainedcrustalhorizontaldeformationinthisregion.Then,wederivedthestrainrateusingamulti-scalesphericalwaveletmethod.ResultsrevealacomplexpatternoftectonicmovementinthesouthernSichuan-Yunnanblock.ComparedtothestableEurasianplate,themaximumrateofthehorizontaldeformationinthesouthernSichuan-Yunnanblockisapproximately22mm/a.TheXiaojiangfaultshowsasignificantlylowerdeformation—aleft-lateralstrike-slipmovementof9.5mm/a.TheHonghefaultclearlyshowsacomplexsegmentaldeformationfromthenorthtosouth.ThenorthernHonghefaultshows4.3mm/arightstrike-slipwith6.7mm/aextension;thesouthernHonghefaultshows1.9mm/arightstrike-slipwith1.9mm/aextension;thejunctionzoneintheHongheandLijiang–Xiaojinhefaultsshowsanobviousclockwise-rotationdeformation.Thestraincalculationresultsrevealthatthemaximumshear-strainrateinthisregionreaches70nstrain/a,concentratedaroundtheXiaojiangfaultandatthejunctionoftheHongheandLijiang–Xiaojinhefaults.Wenotethatmostoftheearthquakeswithmagnitudesof4andabovethatoccurredinthisregionwerewithinthehighshearstrain-ratezonesandthestrainrategradientboundaryzone,whichindicatesthatthemagnitudeofstrainaccumulationiscloselyrelatedtotheseismicactivities.Comparisonofthefastshear-wavepolarizationdirectionoftheupper-crustwiththeupper-mantleanisotropyandthedirectionofthesurfaceprincipalcompressivestrainrateobtainedfromtheinversionoftheGPSdatarevealsthatthedirectionofthesurfaceprincipalcompressivestrainisbasicallyconsistentwiththefastshear-wavepolarizationdirectionoftheuppercrustanisotropy,butdifferentfromthepolarizationdirectionoftheuppermantle.OurresultssupportthehypothesisthattheprincipalelementsofthedeformationmechanisminthesouthernSichuan-Yunnanblockaredeco