简介:Pressuresolutionisacommonphenomenoninmassivesulphidezinc-leaddepositsofwesternCanadaandmayhavebeenanimportantfactorleadingtothemobilizationofore-formingmaterialsduringdiagenesis,deformationandmetamorphismofsedimentaryores.Thecontrolofductileshearzonesovergoldmineralizationcouldbeexplainedinviewofpressuresolutionofgold-bearingminer-alsundershearingstressandthetesultantmobilizationofthismetal.
简介:TheYushugouterrainofhigh-pressuregranulitefaciesinsouthernTianshanMountainiscomposedmainlyofanophiolitesuite.Mostselectedziroconsareroundorellipticalinshape,andsomeareoftetragonalprismwithroundedges.Thegranulometricanalysesshowthattheyarewellsortedinsedimentation.ZrO2/HfO2ratiosinzirconsrangefrom45to57.thesecharacters,togetherwiththepetrologicandgeochemicalcharactersofplagioclase-garnet-orthopyroxenitebearingzircons,indicatethattheprotolithofplagioclase-garnet-orthopyroxenitemaybederivedmainlyfromvolcanicbasesurgesedimentarydebrisinoceanicislandsandfromclaysformedbyseafloorweathering.Zirconsaresimplyofpyroclasticdebris.Theophioliteformationageof(440±18)Maandthefirst-stagemetamorphicage(amphiboliteorgranulitefacies)of(364±5)Mawereobtainedwithamethodofmultiplegrainsindifferentgroupsandamethodofconcordiaplot.TheseagesprovideimportantinformationonthetemporalandspatialoccurrenceofsouthernPaleoxoicTianshanOcean,Thesubductionrateoftheoceaniccrustandtheformationmechanismofophioliteofgranulitefacies.
简介:Wateristhemostactivecomponentinallgeologicalsystems.Ithasanimportanteffectonthephysicalpropertiesofmineralsandmelts.ItalsoplaysakeyroleintheevolutionoftheEarth.Accuratethermodynamicsdataonwaterarecurrentlyconfinedtopressuresbelow1.0GPaandtemperaturesbelow900℃.PresentedinthispaperarenewdataavailableontheP-Tpropertiesofwateratpressuresupto5.0GPa,develogedfromdifferentialthermalanalysisandultrasonicwaveamplitudeanalysis.Ithasbeenfoundthattheremayexistanotherternarypointat3.0GPaandthatultrasonicwaveamplitudechangeofice-watertransitionshowstwoinflectionpointsabove2.0GPa,consistentwiththetwopeaksofdifferentialthermalcurvesabove2.0GPa.Itmaybeanewphenomenonwhichneedsfurtherstudy.