简介：GranitoidsarewidelyspreadintheNanlingRegionofChina.FourrockbodiesintheregionthebeenstudiedfortheirREE,Rb,Sr,BaandScdistributions.Thefourrockbodiesoccurredindifferentlocationsandarecharacterizedasbeingdifferentinageandtype.Therocktypesarepresentedasfollows:Qinghumonzonite,Guangxi;Fuxigranodiorite,Guangdong;Jiufengmonzoniticgranite,Hunan;ZudongK-feldspargranite,Jiangxi.FromthemajorandtraceelementdistributionsinthesegranitoidsitisclearlyshownthatRb/SrratiosintherockstendtoincreasewithincreasingSiO2contentanddifferentiationindex(DI),butLREE/HREE,La/YbandK/Rbratiostendtodecrease,suggestingacorrelationbetweentraceelementdistributionandmajorelementcompositionforthegranitoids.Thedistributioncharacteristicsoftraceelementsineachoftherockbodiesaredescribedindetail.FromthecomparativeanalysisoftheQinghumonzoniteandFuxigranodioriteitisevidencedthattheREEdistributioniscloselyrelatedtothesequenceofcrystallizationfortheminerals,andalsotothepetrochemicaltypesofthesegranitoidsinadditiontotheircrystalchemistry.

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简介：Aglobal-scaleglaciationoccurredatabout600Maago.Asaresult,theEarthbecamethe'SnowballEarth'.Theglaciationcametotheendabruptlywhenatmosphericcarbondioxideincreasedtosuchanextentastobeabout350timesthemodernlevelbecauseofsubaerialvolcanicdegassing.TherapidterminationofglaciationwouldhaveledtowarmingoftheSnowballEarthandextremegreenhouseconditionswouldhavebeencreated.Thetransferofatmosphericcarbondioxidetooceanswouldgiverisetotherapidprecipitationofcalciumcarbonateinwarmsurfaceseawaters,thusformingthecapcarbonaterocksasobservedworldwidetoday.Regionallypersisting,thinlayersofcarbonaterocksdirectlyandubiquitouslyoverlieProterozoicglacialdepositsalmostoneverycontinent,andarecommonlyreferredtoascapcarbonates.Theirunusuallitho-fabrics,stratigraphicallyabruptbasalandupper-levelcontactsandstronglynegativecarbonateisotopicsignatures(δ13Ccarb.valuesrangefrom-7.0‰-0‰)suggestachemicaloceanographicorigin,thedetailsofwhichremainunknown.Itisproposedthattheseenigmaticdepositsarerelatedtothedestabilizationofgaseoushydrateinterrestrialpermafrostfollowingrapidpostglacialwarmingandfloodingofwidelyexposedcontinentalshelvesandinternalbasins.Theauthorscarriedoutstudiesonthegeochemistry,sedimentologyandpalaeontologyoftheSiniancapcarbonatesinGuizhouandHunanprovinces,includingtheoccurrenceofcapcarbonatesofunusualfabrics,stronglynegativecarbonisotopicsignatures,andalotofbitumennodules.Fromtheresultsitissuggestedthatthecapcarbonateswereformedfromsolidmethaneseepage,anditisinagreementwithKennedy'sviewpoint(2001)thatthecapcarbonatesresultedfromtherapidprecipitationofcalciumcarbonateinresponsetosolidmethaneseepage.

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简介：Thesourceofore-formingmaterialshaslongbeenacontroversialfocusbothinmetallogenictheoryandinore-searchingpractice.Thisstudydealswiththeheliumandargonisotopiccharacteristicsofpyritesfrom11golddepositsandsomecountryrocksinthegoldmineralizationconcentratedareaswithinthethreemantle-branchstructuresintheregionofNorthHebeiProvince.Itisindicatedthat3He/4Heratiosinthegolddepositsarewithintherangeof0.93×10-6-7.3×10-6,withanaverageof3.55×10-6;R/Ra=0.66-4.93,averaging2.53;40Ar/39Arratiosvarybetween426and2073,withtheaveragevalueof40Arbeing8.32;andtheaverageof4He/40Arratiosis2.17.3He/4Heratiosingneissandgraniteintheperipheryoftheminingdistrictarewithintherangeof0.001×10-6_0.55×10-6,reflectingsignificantdifferencesintheirsources.3Heand4Hefallnearthemantle,asisshownintheHeconcentrationdiagram.Studieshaveshownthattheore-formingmaterialsinthisregionshouldcomefromthedeepinterioroftheEarth.Withthemulti-stageevolutionofmantleplume,ore-formingfluidsinthedeepinteriorweremovingupwardstoshallowlevels(crust).Undersuchcircumstances,therewouldbeinevitablyoccurcrust/mantlefluidmixing,sotheirnoblegasisotopiccharacteristicsareintermediatebetweenthemantleandthecrust.

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