简介:TheoccurrenceandgeologicalgenesisofpyritesinLatePaleozoiccolasofNorthchinahavebeensystematicallystudiedintermsofcoalpetrology,coalchemistry,elementalgeochemistryandsulfurisotopegeochemistry.Theresultssuggestthateighttypesofpyrite,i.e.,framboidal,automorphicgraular,oolitic,massive,homogeneousspherical,allotriomorphic,nodular,joint-andfisure-fillingpyrintescanbesubdividedunderthemicroscope,Fourgenerationsofpyritearealsoreconizedaccordingtotheshape,size,coexistingassemblage,spacialdistributionrelationshipwithmacerals,thecontentsofsulfurandiron.atomicS/Feratiosandassociatedelementsinpryites.SulfurinLatePalozoiccolasofNorthChinaisofdiversesourceasevidencedbysulfurisotopevariationsinthepyrites.Theδ34Svaluesofpyritegeneratedattheearlystagetedtobenegative,andatthelatestage,positive.
简介:Thisstudyfocusesonthehydrochemicalcharacteristicsof47watersamplescollectedfromthermalandcoldspringsthatemergefromtheHammamRighageothermal?eld,locatedinnorth-centralAlgeria.TheaquiferthatfeedsthesespringsismainlysituatedinthedeeplyfracturedJurassiclimestoneanddolomiteoftheZaccarMount.Measureddischargetemperaturesofthecoldwatersrangefrom16.0to26.5°Candthehotwatersfrom32.1to68.2°C.Allwatersexhibitedanear-neutralpHof6.0–7.6.Thethermalwatershadahightotaldissolvedsolids(TDS)contentofupto2527mg/l,whiletheTDSforcoldwaterswas659.0–852.0mg/l.Chemicalanalysessuggestthattwomaintypesofwaterexist:hotwatersintheup?owareaoftheCa–Na–SO4type(HammamRigha)andcoldwatersintherechargezoneoftheCa–Na–HCO3type(ZaccarMount).Reservoirtemperatureswereestimatedusingsilicageothermometersand?uid/mineralequilibriaat78,92,and95°CforHR4,HR2,andHR1,respectively.Stableisotopicanalysesoftheδ18OandδDcompositionofthewaterssuggestthatthethermalwatersofHammamRighaareofmeteoricorigin.Weconcludethatmeteoricrechargein?ltratesthroughthefractureddolomiticlimestonesoftheZaccarMountandisconductivelyheatedatadepthof2.1–2.2km.ThehotwaterstheninteractatdepthwithTriassicevaporiteslocatedinthehydrothermalconduit(fault),givingrisetotheCa–Na–SO4watertype.Astheyascendtothesurface,thethermalwatersmixwithshallowerMg-richgroundwater,resultinginwatersthatplotintheimmaturewater?eldintheNa–K–Mgdiagram.Themixingtrendbetweencoldgroundwatersfromtherechargezonearea(ZaccarMount)andhotwatersintheup?owarea(HammamRigha)isapparentviaachloride-enthalpydiagramthatshowsamixingratioof22.6\R\29.2%.WesummarizetheseresultswithageothermalconceptualmodeloftheHammamRighageothermal?eld.
简介:Plagioclasephenocrystsfrommaficenclavesandplagioclasefromitshostgranitepossessapat-ternofcomplexzonation.Aplagioclasephenocrystcangenerallybedividedintothreeparts:anoscillatory,locallypatchyzonedcore(An47-19),aringwithdusty,morecalcicplagioclase(An64-20)andanormallyzonedrimcomposedofsodicplagioclase(An22-3.3).Majordiscontinuitiesinzoningcoincidewithresorptionsurfacesthatareovergrownbythemorecalcicplagioclase.Thecoresoflargeplagioclasephenocrystsfrommaficenclavesandhostgraniteshowsimilarzoningpatternsandsimilarcompositions,indicatingtheircrystallizationunderthesameconditions.SteepnormalzoningoftherimsofplagioclasesbothfromhostgraniteandmaficenclavesillustratesadrasticdecreaseinAncontentwhichisconsideredtohaveresultedfromthecontinuousdifferentiationofhybridmagmaandefficientheatlossbecauseoftheupwardemplacementoftheresidualmagma.Widerimsofplagioclasesfromthehostgraniteagainstthediscreterimsofplagioclasesfrommaficenclavesindicatethatdifferentiationandcoolinglastedmuchlongerinthehostgranitethaninthemaficenclaves.
简介:Inductivelycoupledplasmamassspectrometry,inductivelycoupledplasmaopticalemissionspectroscopy,hydridegeneration-atomicfluorescencespectrometry,emissionspectrometry,Xfluorescencespectrometry,andX-raydiffractionwereemployedtostudythegeochemistryandmineralogyofcoalganguesfromNos.2,3,and8coalseamsoftheDu’erpingcoalmine,Xishancoalfield,Taiyuan,ShanxiProvince.Thestudyrevealedthatcomparedwiththesedimentarycover,uppercontinentcrust,Carboniferous-PermiancoalfromNorthChina,aswellasmostcoalinChina,coalganguesfromNos.2and3coalseamsarerichinLi,Be,Sc,Cr,Cu,Ga,Ba,Th,Nb,Cd,Pb,Taandrare-earthelements,andcoalganguesfromNo.8coalseamarerichinLi,Sc,V,Cr,Ga,U,andrare-earthelements.ComparedwiththeCarboniferous-PermiancoalfromNorthChinaandmostcoalinChina,coalganguesfromNos.2,3and8seamsarerichinRb,V,CsandSr.Therefore,TheDu’erpingcoalganguesintheXishancoalfieldarerichinmosthazardoustraceelementsandrare-earthelements,whereinthecontentsofGaandLireachtheindustrialgradeandhavesignificanceforindustrialutilization.Onthewhole,coalganguesoftheShanxiFormationfromthePermianarerichinmoretraceelementsthanthoseoftheCarboniferousTaiyuanFormation.ThedistributionsofREEshowobviouslydippingrightwardswithnegativeEuanomalies.Thecontentsofrare-earthelementsinthethreeseamsarequitedifferent.Alloftheaboveindicatethatthesourceoftherare-earthelementsisterrigenousdebris.MineralsinNo.2seamidentifiedbyX-raydiffractionmainlyincludequartz,kaolinite,inadditiontocalcite,pyrite,apatite,epidote,andepsomite.No.3seammainlycontainsquartz,kaolinite,inadditiontoasmallamountofsodiumfeldspar,calciumnitrate,ironore,gypsum,andvivianite.No.8seammainlycontainskaolinite,dickite,quartz,illite,andasmallamountofhematiteandU.Thecorrelationsbetweenmajorelementsandtraceel
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.