简介：Oxygenisotopefractionationbetweencoexistingmineralsinslowlycooledrocksconveysinformationabouttheircoolinghistory.Byusingthefastgrainboundary(FGB)modeltosimulateclosed-systemdiffusiveexchangeofoxygenisotopesbetweencoexistingminerals,Ishowthattheapparentequilibriumtemperatures(Tae)bythemineralpairwiththelargestisotopicfractionation(PLIF)alwaysliesbetweentheclosuretemperatures(Tc)ofthosetwominerals.Therefore,whentherateofoxygendiffusionandhenceTcforthePLIFchancetobecomparable(suchasinthecaseofquartzandmagnetite),TaewillserveasagoodapproximationofTcregardlessofvariationinmineralproportions.ThespecialtyofthePLIFinconstrainingTaewithintheirTcrangecanbegeneralizedtootherstableisotopesystemsandelementpartitioning.ByapproximatingTcwithTaeandinvertingDodson'sequation,thecoolingrateofplutonicormetamorphicrockscanbeinferred.

简介：Gneiss-distilledwaterinteractionatroomtemperaturewasinvestigatedwithbatch-reactorstostudywater-rockreactionandgeochemicalevolutionoftheaqueousphasewithtime.Theionconcentrationsinwaterwerecontrollednotonlybythedissolutionofprimaryminerals,butalsobytheprecipitationofsecondaryminerals.Thedecreasingfractionsizesofgneisscouldfavordissolutionandprecipitationsimultaneously.Ca2+andK+werethemajorcations,andHCO3-wasthemajoranioninwater.AlltheionsexceptCa2+increasedinconcentrationwithtime.TheCa2+releasefromtherocktotheaqueousphasewasinitiallymuchfasterthanthereleaseofK+,Na+andMg2+.Butafterabout5-24hours,theCa2+concentrationsinwaterdecreasedveryslowlywithtimeandbecamerelativelystable.Duringtheexperiment,thewatervariedfromtheCa-(K)-HCO3-typewatertotheK-Ca-HCO3-typewater,andthentotheK(Ca,Na)-HCO3-typewater.Thewater-gneissinteractionwasdominatedbythedissolutionofKfeldsparinthesolution.Theremainingsecondarymineralsweremainlykaolinite,illiteandK(Mg)-mica.

简介：ApotassiumsolubilizingbacterialstraindesignatedEGT,whichistolerantofhightemperature,wasisolatedfromanearthworm’sguttoobtainabacteriumthatcanweatherpotassium-bearingrockeffectivelythroughsolid-statefermentation.Molecularphylogenyand16SrRNAgenesequenceanalysisdemonstratedthebacterialstrainwasamemberoftheStreptomycesgenus.Toassessitspotentialtoreleasepotassiumfromsilicateminerals,thisstrainwasusedtodegradepotassium-bearingrockpowderbysolid-statefermentation.Afterfermentation,theamountofwater-solubleAl,FeandKofthesubstratewithactiveinoculumwashigherthanthoseofthecontrol,whichhadautoclavedinoculum,andthoseofthefreshsubstrate.Theresultindicatedthatthestrainhadtheabilitytoweatherpotassium-bearingrockandcouldbeusedasaninoculumintheproductionofpotassiumbio-fertilizer,duetoitspotassiumreleaseactivityfromrockandtolerancetohightemperature.