简介：CassiteritesfromboththeBeauvoirandMontebrasgeanitedofFrancearetypicallyrichintraceelementssuchasNbandTa,andcontainquiteanumberofinclusionsofcolumbite(dominantlymanganocolumbite).TwothinsectionsofcassiteritecrystalshavebeenpreparedforRamanmicroprobeanalysis).Thespectraobtainedfromdifferentpartsofthecassiteritesshowthatthevibra-tionfrequencyoftheA1gpeakdecreaseswithincreasingNb,Ta,FeandMnatomiccontents.Itisworthytonotethatanewpeak(namedthe“Anpeak”)hasbeenreportedforthefirsttimeinthepartwithorientedcolumbiteinclusions.Thevibrationfrequencyvariesfrom827to830cm^-1.ThepresenceofthenewpeakmaybeattributedtostructuralchangesofcassiteriteduetotheexcessofNbandTainthelatticeandtheexsolutionofcolumbiteinclusionsincassiterite.

简介：Datingofmetallicoredepositshasbeenoneoftheproblemsconcernedwithbyoregeologistsformanyyears.TheestablishmentoftheRe-OsIsotopeLaboratoryattheInstituteofRockandMineralAnalysis,ChineseAcademyofGeologicalSciences,hasprovideduswithanewtechniquetocarryoutgeochronologicalstudiesofmolybdenumores.AsoneofthemostimportantRe-bearingminerals,molybdenitecontainsalmostnocommonosmium,but^187Oswasderivedcompletelyfromdecayof^187Re,with^187OscontentasthefunctionofRecontentinthemineral.AnID-ICP-MStechniquehasbeenusedinthisstudy,andRe-Osisotopicagesofseverallargemolybdenumdepositsofdiffer-enttypesfromtheEastQinlingmolybdenumbelthavebeendetermined.ItisindicatedthattheHuanglongpucarbonatitevein-typemolybdenum-(lead)deposithasaRe-OsagecorrespondingtoIndosinian,whiletherestporphyry-typemolybdenumdepositsandporphyry-skarn-typemolybdenum-(tungsten)depositshaveRe-OsagescorrespondingtoYenshanian.

简介：Lepingcoal(includingbarkinite-richcoal)isauniquekindofcoal,whichiswidelydistrbutedintheLatePermianLonganFormation,SouthChina,Inthispaper,ROck-Eval,Py-GCandsimulationexperimentviaanopen-systemwereusedtostudythehydrocarbon-generatingpotential,hydrocarboncomposition.andhydrocarbon-generatingmodelofbarkiniterichcoalsfromtheshuichengcoalfieldofGuizhouProvince,SouthwestChina.Theresultsshowthatbarkinite-richcoalshavehighhydrocarbon-generatingpotential,withS1+S2being211-311mg/g,andcanproducelargeamountsofhydrocorbonatthehigh-maturitystage,mostlywithinthetemperaturerangeof420-450℃(correspondingtoVR01.1-1.5%);barkinite-richcoalisoneofthebetteroilsourcesandlighthydrocarbonandwetgasarethemajorhydrocarboncomponents,whichaccountfor45%and33%ofthetotalhydrocarbons.respectively.ThesecharacteristicsareofimportanceforexploringoilandgasresourcesintheLatepermianLongtanFormationcoals,southwestChina.

简介：

简介：Icecoreδ18OrecordefromtheNo.aglacierattheheadoftheUrumqiRiverwereusedocharacterizetherelationshipbetweenδ18Oandcontemporaneoussurfaceairtemperature(Ta)nearbytheDaxigouMeteorologicalStation(3539mabovesealevel,-2kmawayfromtheicecoredrillingsite),Althoughtheicecorerecordsofannuallyaveragedδ18Oarepositivelycorrelatedwithconemporaneoussurfaceairtemperature,especiallysummerairtemperature,thecorrelationislesssignificantthanthatfortheprecipitationsamplesduetodepositionalandpost-depositionalmodificationprocesses,However,theClimatologicalsignificanceoftheicecorδ18Orecordscanbestillpreservedtoacertaindegree,whichmoghtextendtheapplicationofhighaltitudeandsub-tropicalicecoreδ18Orecordstopaleoclimatereconstruction.

简介：

简介：TheDachangtin-polymetallicdistrict,Guangxi,China,isoneofthelargesttinorefieldsintheworld.Bothcassiterite-sulfideandZn-CuskarnmineralizationarehostedintheMid-UpperDevoniancarbonate-richsedi-mentsadjacenttotheunderlyingCretaceousLongxianggaigranite（91-97Ma）.TheLamoZn-CudepositisatypicalskarndepositinthedistrictandoccursatthecontactzonebetweentheUpperDevonianlimestoneandthegranite.Theoremineralsmainlyconsistofsphalerite,arsenopyrite,pyrrhotite,galena,chalcopyrite,andminormolybdenite.However,theageofmineralizationandsourceofthemetalsarenotwellconstrained.Inthisstudy,weusethemolybdeniteRe-Osdatingmethodandin-situPbisotopesofsulfidesfromtheLamodepositforthefirsttimeinordertodirectlydeterminetheageofmineralizationandthetracingsourceofmetals.SixmolybdenitesamplesyieldedamoreaccurateRe-Osisochronageof90.04-1.1Ma（MSWD--0.72）,whichismuchyoungerthanthereportedgarnetSm-Ndisochronageof95±11MaandquartzfluidinclusionsRb-Srisochronageof99±6Ma.ThisageisalsointerpretedastheageofZn-Cuskarnminer-alizationintheDachangdistrict.Further,inthisstudywefoundthatin-situPbisotopesofsulfidesfromtheLamodepositandfeldsparsinthedistrict＇sbiotitegraniteandgraniticporphyrydikeshaveanarrowrangeandanoverlapofPbisotopiccompositions（206pb/204pb18.417-18.594,207pb/204pb=15.641-15.746,and208pb/204pb=38.791-39.073）,suggestingthatthemetalsweremainlysourcedfromCretaceousgraniticmagma.