非传统稳定同位素-6a-应用实例

白云鄂博矿床成因朱祥坤中国地质科学院地质研究所白云鄂博:富饶的神山丁道衡先生1927年发现铁矿石何作霖先生1936年发现含REE矿物(独居石)新中国成立后建立的第一座铁矿山白云鄂博矿区丁道衡塑像

BayanOboREE-Nb-FedepositThelargestLREEoredepositintheworldAlargeNbdepositALargeFedepositTimingofMineralisationOriginoftheDepositGeologicalmapofBayanObooredeposit(afterBaietal.,1996)1—Overthrust;2—Inferredfault;3—Geologicalboundaries;4—Inferredgeologicalboundaries;5—Ironbodies;6—Carbonatitedykes;7—Ore-hosteddolomite;8—Fluoritetypeironores;9—Massivetypeironores;10—Aegirinetypeironores;11—Riebeckitetypeironores;12—Dolomitetypeironores;13—Biotitetypeironores;14—Samplelocation;15—Locationofdrillhole.H1~H15—UnitofBayanOboGroup,seetable1;C—Carboniferous;Q—Quaternary;H—Relictsofslateandquartzite;DT—Dolomitemarble;ST—Mineralizedslate;ε—Meta-ultrabasicrocks;µ—Migmatiticgneisses;γ—Granites;γµ—MigmatiticGranites;δ—Basic-intermediaterocksTheore-hostingdolomitemarbleTheore-hostingdolomitemarbleMt：magnetiteHm：hematiteRE：REEmineralsAe：aegirineFl：fluoriteFlHmAeMtREREREMtAeHmFlFlIronoresLate-stageveinsDol:dolomite；Fl：fluorite；Mon：monaziteMonDolDolDolFlThenormalcarbonatesedimentsonthenorthofKuangouMt0.5mmMtREAeMt：magnetiteRE：REEmineralsAe：aegirineMtDolFl0.5mmMtDolMt：magnetiteDol：dolomiteFl：fluorite0.5mmMtHmMt：magnetiteHm:hematiteFl：fluoriteFlCarbonatitedykesDolBarREDol：dolomite；RE：REEminerals；

Bar：barite1mmTimingofMineralisationOriginoftheDepositSm-Nd同位素体系:REE铁同位素：Fe矿镁同位素：白云质大理岩（寄主岩石）(143Nd/144Nd)p=(143Nd/144Nd)i+147Sm/144Nd(eλt-1)Singlesourceatt0(143Nd/144Nd)p=(143Nd/144Nd)i+147Sm/144Nd(eλt-1)Singlesourceatt0Twosourcesatt0andt1respectively(143Nd/144Nd)p=(143Nd/144Nd)i+147Sm/144Nd(eλt-1)Singlesourceatt0Twosourcesatt0andt1respectivelySinglesourceatt0,recrystalisedatt1(143Nd/144Nd)p=(143Nd/144Nd)i+147Sm/144Nd(eλt-1)Allpublisedwhole-rockdata,ca.1.3Ga;εNd(t)=-0.2

TimingofREEMineralizatiomInitial/mainmineralization:ca.1.3Ga,mantlesource;Latestagemineralization:ca.0.44Ga,internalrecyclingOtherages:disturbance

TimingofMineralisationOriginoftheDepositTheorigin:hotdebateSedimentaryorigin?Hydrothermalorigin?Magmaticorigin(carbonatite)?Multipleorigin?MgIsotopes:24Mg,25Mg,26MgFeIsotopes:54Fe,56Fe,57FeCarbonatesedimentsIgneousrocksMgisotopes—Differentgenetictypesofrocks*****

ReferencedataMgisotopes—BayanObooredeposit*

Referencedata*Feisotopes—Differentgenetictypesofironores&rocks*

Referencedata**********Feisotopes—varioustypesofrocksfromBayanOboorebodies

Thenormaldistributionofδ56Fevaluesforironores(bulksampleandFeoxides)**********FeisotopecompositionsofBayanObooredeposit*

ReferencedataSummaryNd:mantlesourceMg:magmaticoriginFe:magmaticoriginSr:mantlesourcemainly(mantle+?)C-O:doublesources(mantle+?)小结Sm-Nd同位素体系:REE铁同位素：Fe矿镁同位素：白云质大理岩（寄主岩石）小结全岩的Sm-