DSpace at VNU: Metamorphic evolution of pelitic–semipelitic granulites in the Kon Tum massif (south-central Vietnam)

DSpace at VNU: Metamorphic evolution of pelitic–semipelitic granulites in the Kon Tum massif (south-central Vietnam) tài...

j ourna l h o me p ag e:h t t p : / / w w w e l s e v i e r c o m / l o c a t e / j o g

a VNU-Hanoi University of Science, 334-Nguyen Trai Str, Hanoi, Viet Nam

b Laboratoire de Géoscience, Université Montpellier 2, Montpellier, France

c Laboratoire de Tectonique, Université Pierre et Marie Curie, Paris, France

d Department of Geology, National Taiwan University, Taipei, Taiwan

Article history:

Received 12 August 2010

Received in revised form 29 March 2012

Accepted 30 March 2012

Available online 11 April 2012

Keywords:

Kon Tum massif

Granulite

Metapelite

Indosinian

Vietnam

© 2012 Elsevier Ltd All rights reserved

1 Introduction

The Indosinian orogeny in late Permian and Triassic times

(Fromaget, 1941) is the expression of thecollision of different

Gondwana-derivedcontinentalterrains(Indosinia,Sibumasu,and

SouthChina),afternarrowingandsuturingofdifferentbranchesof

thePaleotethys(Metcalfe,1996;Lepvrieretal.,2004).The

south-centralareaofVietnamterritorywhichcorrespondstotheKonTum

massif(Fig.1A)exposeswidespreadhightemperaturecrystalline

rockssubdividedintofourlithologicalunits:granuliticfaciesKan

Nackcomplexinthesouth-east;amphiboliticfaciesNgocLinh

com-plexincentral;greenschists-amphibolitefaciesKhamDuccomplex

inthenorthand– greeschists-amphiboliteSaThay(DienBinh)

complexinthewest,whichiscommonlyregardedasanoldand

∗ Corresponding author Tel.: +84 4 35 58 70 60; fax: +84 4 38 58 30 61.

E-mail address: tichvv@vnu.edu.vn (V.V Tích).

stablePrecambrianbasement(PhanCuTienetal.,1989).Becauseof theoccurrenceofhigh-temperaturemetasedimentaryandigneous seriescomprisinggranulitesandcharnockites,thismassifhas clas-sicallybeeninterpretedasafragmentofGondwana,equivalentin agetothesamefaciesrockswhichareexposedinsouthernIndia andAntarctica(Katz,1993).However,recentisotopicdatashow thattheKonTumbasementwasaffectedbyPermo-Triasic tectono-metamorphicevent(TranNgocNametal.,2001;Nagyetal.,2001; Osanaietal.,2001;Maluskietal.,2005)

Thereis nowabroadrecognitionofthevarietyofP–Tpaths and tectonicsettings tobefoundin granulite-facies terrains.It wasfirstlyassumedthatgranuliticrocksinorogenicbeltstypically experiencedacrustalthickening(EnglandandRichardson,1977) Somemodels wereproposed toaccount for type of retrograde path suchas: metamorphismin extensionalterrains(Sandiford andPowell,1986)orinterrainsheatedbytheadditionof volumi-nousmagmas(Bohlen,1987).Whenpartsoftheprogradehistory (isobaric heating)could bedetected,it suggests thatmagmatic 0264-3707/$ – see front matter © 2012 Elsevier Ltd All rights reserved.

Fig 1. (A) Location of the Kon Tum massif; (B) geological sketch map of the Kon Tum Massif and more detail of the Kan Nack complex (modified after Phan Cu Tien et al.,

1989 ); (C) folliation data from the Kan Nack complex (along the Song Ba and the Song Bien reiver); (D) Interpretative section of the Kan Nack complex [1 granulites; 2 gneiss, micaschists (the Ngoc Linh Complex: Metamorphic cover of the Kan Nack Complex); 3 Paleozoic sediment; 4 charnockites; 5 Undeformed granites (Late Triassic and Cretaceous); 6 Cenozoic basalts; 7 Mesozoic sediments; 8 quaternary sediments], Vn811 sample location.

accretionhadplayedanimportantroleinheatadvection(Sandiford

andPowell,1986)

Previous studies have given an idea of the globalevolution

ofthearea,butthediversityinprotolithofgranulitesfrom

dif-ferent places obtainedby previous works (Osanaiet al., 2004)

showthatthethermo-tectonicsettingoftheKonTummassifis

morecomplicatedindetail.Moreover,thelargeexposureofpelitic

andsemipeliticanatecticgranulites(granuliteleucosomes)inthe

KonTumbasement which isimportant tounderstand

tectono-metamorphicsetting,which hasnot beenstudiedin detail.The

questionthereforehastobeasked,isthemetamorphicP–Tpath

of metapeliticgranulitic leucosomes observed in the KanNack

complexasingleisothermaldecompressionand decompression

coolingpathordoesitreflectaprograde(decompressionheating)

andisothermaldecompression?So,detailedpetrogeneticdataare

neededtoconstraintectono-metamorphicevolutionofthisarea

Inthethispaper,wepresentheredetailedpetrography,

min-eralassemblage,and mineralchemistry oftheKan Nackpelitic

granulitesinordertounderstandthemetamorphichistorythrough reactiontexturesobservedcombiningwithP–Ttrajectoryand ther-mobarometriccalculations.Thisdatawillbeinterpretedinthelight

ofpreviousworks(geochronologydata)inordertodiscussmore aboutthethermo-tectonicevolutionoftheKonTummassifandits roleduringtheIndosinianorogenicevolution

2 Geological setting of the Kon Tum massif and the Kan Nack complex

Thestudiedarea(KonTummassif)islocatedinsouth-central Vietnam (Fig 1A) The Kon Tum massif exposes a large scale

of crystalline rocks It consists of mainly metasediments and orthogneisses,which weremetamorphosedin amphiboliticand granulitic facies (PhanCu Tienet al., 1989).This metamorphic basementiscovered fromplacetoplace byPaleozoic-Mesozoic sedimentsorevendirectlybyNeogenetoQuaternarylavaflows (Lee et al.,1998),and intrudedbyundeformedJurassic-Triassic

oftheKonTummassif,thePaleozoicsedimentsarenearlyabsent

intheKonTummassif.Basedonmetamorphicgrade(PhanCuTien

etal.,1989),KonTummassifhasbeensubdividedintodifferent

complexessuchastheKanNackcomplexcomposedessentiallyof

granuliticandcharnockiticrocks;theNgocLinhcomplex

contain-inglower-grademetamorphicrocksinamphiboliticfacies;theSa

Thaycomplexcontainingmetapeliticandmagmaticgneissicrocks,

nowsocalledDienBinhunit(Maluskietal.,2005)andKhamDuc

amphibolitefaciescomplex(kyaniterocks)whichwasatransition

zonebetweentheTruongSonbeltandtheKonTummassif

Structurally,theKonTummassif(Fig.1B)isessentiallyaffected

bytwoshearzonesystems.ThewesternpartoftheKonTumMassif

isboundedbyamajorN-Sfault,asinferredbytypical

geomorpho-logicfeatures,whichcanbefollowedoveratleast200km,running

fromPhuocSonalong thePoKoriver, andnamed “PoKo fault

zone”(Fig.1B).AtthelatitudeofDakTo,thePoKofaultswings

eastwardsandsplaysindifferentbranchestowardstheSaThay

val-leyandtowardstheKonTumbasinandprobablyextendsmoreto

theSouthbeneaththePleikuplateau-basaltsreachingthecourse

ofDaRangriver.Thekinematiccriteriasobservedonmylonites

alongthisfaultzoneindicateasinitralductilefault.Thissocalled

PoKofaultcoincideswiththeboundaryoftwodistinctand

con-trastedpetrologicdomainsintheKonTumbasementwhichare:To

theEastofthefaultareexposedrecentlydiscoveredcharnockitic

andgranuliticrockswhichconstitutethewesternmostoccurrence

ofthismaterial.TotheWest,theexposedrocksarerepresented

bytheDienBinhunit (Fig.1B),whichistectonicallyadifferent

unit,mainlyconsistinginlessdeformedandnon-granulitic

meta-igneousrockswitholderthan250Ma(VuVanTich,2004).Mafic

andultramaficrocksassemblagesofophioliticaffinitiesare

tecton-icallyenclosedaselongatedlensesandshearedbodieswithinthe

PoKofaultzone.Assemblagesofophioliticaffinitiesarepresent

alongthisfaultzone,whichwasconsideredasapaleosuture(Tran

VanTri,1986)andresultinginasinistralobliquesubductionofKon

Tummicro-continentbeneathtoKhoRatmicro-continent(Lepvrier

etal.,2004).Inthenorthernpart,theKonTummassifwasaffected

byaseriesoftheE–Whightemperaturedeformedshearzones

ofTraBong–PhuocSon(KhamDuc),progressivelybend

north-westwardstoconnectwiththePoKoFault(Fig.1B)whichforms

thetransition with theTruong Son belt Along this fault zone,

rocksarehighlydeformedinultramylonitefacieswherefibrous

sillimanitedominates.Kinematiccriteriaobservedalongthisfault

zoneshowsadextralmovementwitha60–70◦ dippingfoliation

tothe south Ngoc Linh complex is limited by two these fault

zonestothewestandthenorth.Rockofthiscomplexare

princi-pallyinbiotite-hornblendegneisses,amphibolites,biotite-fibrous

sillimanite-garnetbearingschistsandgraphiteschists.Alongthe

cross-sectionfromKonTumcitytoSongReRiver,through

Konp-long,theserocksformawideantiformwhichexhibitsnormalshear

movementsonbothflanks,whilealargegraniticundeformedbody

occupiesthecoreofthestructure(Maluskietal.,2005)

TheKanNackcomplexissituatedincentral-easternpartofthe

KonTumblock,separated withtheNgocLinh complexby two

mainshearzonesmentionedabove.DifferingfromtheNgocLinh

complexinmetamorphicgrade,theKanNackcomplexpresentsa

basementwithmainlyanatecticgranuliticrocks.Geologicalmaps

ofVietnamshowvariousnames(KonCot,XaLamCo,DakKoand

KimSonunit)whichidentifythedifferentstratigraphicunitsof

theKanNack complex.Butthisterminology generallyrefersto

localtoponymyandmanynamescorrespondinfacttothesame

petrologicunits To clarifyand simplify this situation,many of

thislocalformationshavebeengrouped,takingonlyintoaccount

theirmineralassemblagesandmajorpetrologicalcharacteristics,

whatevertheirdegreeofdeformationandtheirgeographic

loca-tion.Nevertheless,wehavemaintainedusualterminology,when

justified.We observedalongtheuppercourseof SongBaRiver (Fig.1B),thisbasementexposedbyAl-richmetapelites,quartzites andmarbles.Maficgranulites,probablyUHTgranulites,although moderatelydeformed,arepresentedaslensesofanatecticpellitic granulites Structurally, they present low tomoderate dipping-foliation,locallymyloniticandformgentledomestructures(Fig.1C, D) Whole of this basement is intruded by charnockitic rocks Charnockitic bodies, represented essentially by enderbites and locallynorites,occurinthecoreofthisstructure(Fig.1D).NearKan Nackvillage,inclusionsoffoliatedgranuliteswithinthe charnock-iteshavebeensimilarlyobserved(Fig.2).TheKanNackcomplexis consideredtobesurroundedbyagneissicandschistosedmaterial, formingtheamphibolitefaciesNgocLinhComplex(PhanCuTien

etal.,1989).Thelimitbetweenthistwocomplexissometimesin faultedcontact(Fig.1)

Availablegeochronologicdatashowthat theKonTum base-mentwasaffectedatleastby threemaintectono-metamorphic events.Theoldesteventoccurredaroundof1400Ma,evidenced

byageoncoreofzirconfrompeliticgranulitedatedbyShrimps method(TranNgocNametal.,2001).Thisresultisexplainedas agefromProterozoicrocksintheKonTummassifcrust corrob-oratedbyTMD fromSm/Nddataofgranuliteandcharnockitein theKanNack complex.The middletectono-metamorphicevent tookplaceataroundof400–670Ma.Thiseventisevidencedby someagesof439and451Maisobtainedfromamphiboliticgneiss andorthogneissfromDienBinhunit(Fig.1B)datedrespectivelyby U–Pband40Ar–39Armethod(Nagyetal.,2001).ASRHIMPresult with401–418Mawasobtainedfromorthogneissinnorthernpart

of theTra Bong(Fig.1B)shear zone(Carter etal.,2001).Some recentdataobtainedbydifferentmethodsgivesimilarresults:a

678MaSm–NdageforremainingamphibolitefromKanNack com-plex(Nakanoetal.,2003);479MaonmonaziteoftheUHTgranulite (smallboudinsofmaficgranuliteinpeliticbasement)obtainedby U–Th–PbCHIME(Osanaietal.,2001);405–403Maonbiotitesof granuliterelicinapolymetamorphicgreen-schists,fromthe east-ernpartoftheKanNackcomplex,obtainedby40Ar–39Armethod (Maluskietal.,2005).Thethirdeventtookplaceduring Permian-TriassictimeandmarkstheIndosinianorogeny,namedforfirst timebyFrenchgeologist(Fromaget,1941),andexpressedasa col-lisionbetweendifferentGondwanianblocks(Lepvrieretal.,2004) Thiseventwasrecordedbyradiometricmultimethodson differ-entrocksnotonlyintheKonTummassifbutalsointheTruong Sonbelt(Lepvrieretal.,1997;Loetal.,1999;Maluskietal.,2005),

onHainanisland(southChina),andalsointhesouthChinablock

asnotedinCarteretal.(2001).Thefirstevidenceforthiseventin KonTummassifisanageof235–246Maobtainedby40Ar–39Ar methodonbiotiefromdifferentmetapeliticgranulitesintheKan Nackcomplex(Maluskietal.,2005).Theseagesareconfirmedby SHRIMPmethod,equivalenttopeakmetamorphicageof254Ma Thesameresult(242,250and238Ma)hasbeenobtainedbythe U–Th–PbCHIMEmethodforultrahightemperaturegranuliteinthe KanNackcomplex(Osanaietal.,2001).Alltheseagesforgranulites correlateswellwithemplacementageofthecharnockiticintrusion

at251Maonfiveconcordantzirconofthesamerock(Nagyetal.,

2001)and258.5MabytheSHRIMPtechnique(Carteretal.,2001)

3 Petrography, mineral chemistry and P–T path of pelitic granulites

Petrologicaldatawereobtainedaftera detailedstudyunder microscopeandanextensivestudywithCamebax-50EPMAat Uni-versityofMontpellierIIinFrance.Therocktype,samplelocation andmineralassemblageofeachsamplearepresentedinTable1 Representativeelectronicmicroprobeanalysesofthemineralogical phasesaregiveninweight%andcationsperformulaunits,where

Fig 2. Field observation photos in the Kan Nack complex from the Kon Tum massif: (A) contact granulite (dark and banded) and enderbitic charnockite (white color), (B) banded pelitic granulites.

molarfractionsare alsogiven(Table2).Someparticularities of

studiedmineralsarediscussedinthetext.Allmineralabbreviations

inthetable;figureandthetextareofPowellandHolland(2001)

3.1 Petrography

WehaveobservedgranulitesalongtheSongBienbrook,south

ofHoaiAntownandalongtheSongBaRiver(Fig.1B).They

consti-tutethebasementoftheKanNakcomplex.Originally,theprotolith

ofgranuliteswasconstitutedbysedimentaryAl-richseries.They

containedpelites,semipelites,sandstonesandAl-quartzites

Cal-careousanddolomiticsedimentswereintercalated.Now,allthese

sediments are found as high-temperature metamorphic rocks,

in thegranulite facies, giving rise tokhondalitic and kinzigitic

bandedanatecticgneisses(Fig.2B),granuliticmetaquartzitesfor

themoresiliceousprotoliths,andforsterite-humitecalc-schistsfor

thescarcecalcareous-dolomiticones

Inthefieldasinhandspecimen,thesehigh-grademetapelitic

rocksshowvery intense layering and banding Thislayering is

partlycompositional,anatecticandtectonic.Thedarklayersrich

ingarnet, cordierite,biotiteand prismatic sillimaniterepresent

thegneissic paleosomes or the residual melanosomes often as

boudinswrappedbytheregionalfoliation.Thewhitelightlayers

representquartzo-feldspathicleucosomes(anatecticpeakliquid)

Thesetwokindsoflayersarealwaysparallelwiththefoliation

Fromthepointofview,thesegranulitesaretruemetatexites.The

diatecxitestageoffusionhasnotbeenreached.However,thevery

localintrusionofcharnockites.lmagmaticliquid,cross-cuttingthe

bandedgranulitefoliationisevenconfusingasitlookslikeas eval-uateddiatexite(Fig.2)oreven agmatite.Thegranulitelayering

isalsocompositionalsincequarziticorsemi-peliticlayers (some-timezincian-poororzincian-richequilibrium),khondaliticquartz, K-feldspar layers, kinzigitic plagioclase rich, quartz poor layers coexistparallelinthesameoutcrops.Theobservationof associ-atedcalcarousdolomiticdeformedpodsorlayerforsterite-humit, calc-schistandmarblesstronglysupportsthisidea.Atlast,allthis high-graderocksexhibitahugetectonicbanding.Theyarestrongly deformedinductileconditions.Theyareintensivelyfoliatedand lineated.Thisisdemonstratedbyastrongstretchinglineationinthe mainmyloniticshearzones,revealedbyelongatedprismatic silli-manite,platenquartzribbonsandovalgarnets(Fig.3).Underthe microscope,themineralogiesofalltheselayersisdifferent accord-ingtothebulk-rockcompositionsoftheirprotolitegivingriseto quartz,acidicplagioclase,K-feldspar(mesoperthiticornot),biotite, andsometimesalmandine-pyropegarnetandsillimanitegranulitic leucosomes(Figs.4and5).Anatecticconditionsarereachedwithin thestablebiotite/quartzandgarnet/K-feldspar/sillimanite/Zn–Fe richspinelstabilityfields

Quartz, K-feldspar, acidic plagioclase, Ti–Mg rich-biotites, Fe–Mggarnet,Mgrich-cordierites,prismaticsillimanite,Fe–Mg–Zn spinels are the main granulitic phases Graphite, Mg-ilmenite, Fe-sulphides, apatite and zircon are the main accessory min-erals Magnetite and Ti-magnetite are rare and always altered

inhydrated-hematite(martite).Zirconpresentssometimes over-growths When present, rutile has only been observed in the mostaltered granulites samples.Yellow monaziteand perhaps

Table 1

Mineral assemblage observed in some metasedimentary granulitic rocks in Kan Nack complex.

Vn354, 355 14◦1804, 108◦2901 Aluminium granulitic quartzite qtz, pl.ap, Ksp.mp, Ti-bi, ga, sil.p, crd, rt, Fe-Ti ox, chl2, pn2, mus2 Vn356 14 ◦ 18  04  , 108 ◦ 29  01  Calc-silicate per, for, phl, grt, graph, zn, serp2, chl2

Vn373 14 ◦ 15  15  , 108 ◦ 45  11  Khondalito-kinzigitic granulite qtz, pl.ap, Ksp.mp, bi, crd, ilm, zn

Vn379 14 ◦ 23  06  , 107 ◦ 52  21  Khondalito-kinzigitic granulite qtz, pl.ap, Ksp.mp, bi, crd, ilm, zn

Vn413 14 ◦ 18  04  , 108 ◦ 29  01  Pelitic granulite qtz, pl.ap, Ksp.mp, Ti-bi, ga, sil.p, crd, zn, graph, rt, chl2, pn2, mus2 Vn414 14 ◦ 18  04  , 108 ◦ 29  01  Granulitic quartzite qtz, pl.ap, Ksp, bi, sil.p, ga, sp, zn, ap

Vn415 14◦1804, 108◦2901 Pelitic granulite qtz, pl, Ksp.mp, bi, ga, sil.p, crd, spl, dsp2, pn2

Vn514 14◦1804, 108◦2901 Granulitic anatectic gneiss qtz, Ksp.mp, Ti-bi, ga, crd, chl2

Vn515 14 ◦ 18  04  , 108 ◦ 29  01  Granulitic gneiss qtz, pl.ap, Ksp, crd, Ti-bi, ga, pn2, sc2, chl2

Vn803 14 ◦ 13  47  , 108 ◦ 30  53  Quartzitic granulite qtz, Ksp.mp, bi, grt, sil.p, graph, zn, ap, chl2, mus2

Vn362 14 ◦ 13  47  , 108 ◦ 30  53  Quartzo-feldspathic granulite qtz, pl.ap, Ksp.mp, bi, sil.p, ga, spl, rt, Fe-Ti ox, chl, mus

Vn363 14 ◦ 13  47  , 108 ◦ 30  53  Metatectic granulite qtz, pl.ap, Ksp.mp, Ti-bi, ga, sil.p, crd, spl, chl2, mus2, pn2, dsp2 Vn805 14 ◦ 13  47  , 108 ◦ 30  53  semi-pelitic granulite qtz, pl.ap, Ksp.mp, Ti-bi, ga, crd, spl, chl2, ms2, pn2, dsp2

Vn811 14◦1207, 108◦3204 Granulitic quartzite qtz, pl.ap, Ti-bi, ga, zn, ap, chl2.

Table 2

Representative analyses of the main mineral phases in the granulites terranes of the Kontum Block (Song Ba river: Vn356a, Vn362, Vn363; Song Bien Brook: Vn413, Vn414, Vn415) Vn413/Vn413-S1 and Vn414/Vn414BB/Vn414-S4/Vn414-1 ◦ Vn414-2/VN414p represent different compositional layers in two representative samples from the two main outcrops granulitic area (a) Spinels (sp) The number of ions in the spinel formula is based on 4 oxygens and the sum of cations is recalculated to 3 (sp2: secondary spinel in the reactional cordierite corona around garnet; cmp incl., composite inclusion; mph, mesoperthite); (b) K-feldspars (ksp) The number of ions in the K-feldspar formula is based on 8 oxygens (Xab, Xalbite; Xor, Xorthose; Xan, Xanorthite); (c) Plagioclases (pl) The number of ions in the plagioclase formula is based on 8 oxygens (Xab, Xalbite; Xor, Xorthose; Xan, Xanorthite pl2: secondary plagioclase in the cordierite-spinel reactional corona around garnet); (d) Biotites (bi) and phlogopites (phl) The number of ions in the black-micas formula is based on 10 oxygens and 2 (OH) (synf., synfolial; incl in, inclusion in; /, against (e.g bi/ga: biotite against garnet); crd2: secondary cordierite in the reactional corona around garnet; gpt: graphite; cmp incl.: composite inclusion); (e) Garnets (ga) The number of ions in the garnet formula is based

on 12 oxygens and the sum of cations is recalculated to 8 (Xalm, X almandin; Xpyr, Xpyrope; Xgro, Xgrossular; Xspe, X spessartite); (f) Cordierites (crd) The number of ions in the cordierite formula is based on 10 oxygens (crd1, primary with biotite and sillimanite; crd2, reactional cordierite); (g) Prismatic sillimanite (sil) The number of ions in the sillimanite formula is based on 5 oxygens; (h) Ilmenites (il) The number of ions in the ilmenite formula is based on 3 oxygens and the sum of cations is recalculated to 2 (sulph, Fe-sulphide; Xil, Xilmenite; Xhm, Xhematite; Xgk, Xgeikileite; Xpy, X pyrophanite); (i) magnetites (mt) The number of ions in the magnetite formula is based

on 4 oxygens and the sum of cations is recalculated to 3 (Xmt, Xmagnetite; Xulv, Xulvöspinel).

(a) Spinel (spl)

Vn362 incl.

in ga core

Vn363 sp2 core

Vn414.S4 matrix sp core

Vn414.S4 cmp incl in ga

Vn414B incl in ga core

Vn414B matrix sp rim

Vn414B incl in bi core

Vn414BNL inc in sil core

Vn413 incl.

in mph core

Vn415 sp2 incl bi core

Vn415NL sp2 core

Al 2 O 3 60.91 58.34 60.22 60.92 59.82 57.55 58.51 57.52 57.79 57.00 58.53

Sum 100.93 100.50 100.32 100.09 101.82 100.55 101.36 99.76 101.29 100.90 100.69

XFe 2 0.623 0.836 0.653 0.605 0.714 0.853 0.810 0.768 0.849 0.866 0.741 XFe 3 0.015 0.016 0.018 0.012 0.030 0.028 0.013 0.032 0.038 0.037 0.035 (b) K-felspars (Ksp).

Vn362 ksp Vn362 ksp2 Vn362 ksp Vn362

antiperthite

Vn362NL antiperthite

Vn363 ksp Vn363

antiperthite

VNn14B ksp VNn14B ksp VNn13 ksp Vn413 ksp

Al 2 O 3 19.56 19.13 19.15 19.07 19.26 18.86 19.11 19.21 19.23 19.02 19.08

Sum 99.74 98.84 100.02 99.57 99.58 98.35 99.75 99.89 100.11 100.36 100.5

(c) Plagioclase (pl)

Vn356a pl Vn362 pl Vn363 pl Vn363 pl2 Vn363 pl2 Vn414.S4 pl Vn414.S4 pl Vn414B pl Vn414B pl Vn413 pl Vn413-S1 pl Vn415 pl Vn415 pl Vn415 pl2 SiO 2 64.99 57.61 58.08 55.89 56.34 60.66 60.19 60.86 59.43 67.14 66.1 53.11 57.17 51.72

Al 2 O 3 20.23 27.15 25.9 28.31 27.91 24.41 25.06 24.94 24.89 21.43 20.97 29.95 27.49 30.7

FeO 0.05 0.24 0.02 0.51 0.37 0.3 0.09 0.09 0.13 0.1 0.01 0.74 0.52 5.15

Na 2 O 7.43 6.59 7.05 5.94 6.2 8.17 7.84 8.53 7.81 10.87 8.04 4.76 6.55 6.08

K 2 O 3.86 0.19 0.35 0.19 0.15 0.09 0.14 0.12 0.6 0.08 3.86 0.04 0.06 0.22

Sum 96.92 100.56 99.07 100.73 100.49 99.42 99.36 100.51 98.92 100.99 100.37 100.36 100.71 102.23

Si 2.956 2.57 2.622 2.501 2.523 2.713 2.691 2.695 2.68 2.914 2.921 2.4 2.55 2.336

Al 1.085 1.427 1.378 1.494 1.473 1.286 1.32 1.302 1.323 1.096 1.092 1.595 1.445 1.635

Fe 2 0.002 0.009 0.001 0.019 0.014 0.011 0.003 0.003 0.005 0.004 0.001 0.028 0.02 0.195

Ca 0.017 0.418 0.367 0.474 0.454 0.272 0.287 0.282 0.29 0.062 0.063 0.569 0.423 0.39

Na 0.655 0.57 0.617 0.516 0.538 0.708 0.68 0.732 0.683 0.915 0.689 0.417 0.566 0.533

K 0.224 0.011 0.02 0.011 0.008 0.005 0.008 0.007 0.034 0.004 0.218 0.002 0.004 0.013

Sum 4.941 5.006 5.007 5.015 5.012 5 4.992 5.023 5.017 4.997 4.985 5.012 5.011 5.118

Xan 0.02 0.42 0.37 0.47 0.45 0.28 0.29 0.28 0.29 0.06 0.07 0.58 0.43 0.42

Xab 0.73 0.57 0.61 0.52 0.54 0.72 0.7 0.72 0.68 0.93 0.71 0.42 0.57 0.57

Table 2 (Continued )

(d) Biotite (bi)

Vn353 bi

synf core

Vn356a bi synf core

Vn362 synf./ga core

Vn362 synf.

core

Vn362 incl.

in ga core

Vn363 incl.

in ga core

Vn414.S4 synf phl/ga core

Vn414B synf core

Vn414 synf rim

Vn414B synf/ga rim

Vn413 synf./sil core

Vn415 included in

sp core

Vn415NL incl in ga core SiO 2 37.71 38.79 36.66 37.75 36.43 36.83 37.3 35.53 35.94 36.81 33.62 36.35 35.57

Al 2 O 3 17.76 17.08 16.15 16.3 16.3 15.32 18.46 17.9 18.21 17.46 18.31 18.36 16.62

MgO 12.81 12.03 14 15.36 14.77 12.63 18.01 13.43 12.37 14.45 10.66 13.13 16.76

FeO 13.03 12.42 13.84 13.52 12.12 16.15 9.74 14.94 16.15 13.82 19.5 15.87 11.25

Na 2 O 0.14 0.19 0.22 0.22 0.34 0.17 0.08 0.14 0.06 0.12 0.22 0.18 0.41

K 2 O 9.35 9.3 9.91 9.68 9.47 9.64 9.99 9.99 10.32 10.23 9.79 9.64 9.35

Sum 101.17 99.1 99.55 100.17 99.61 100.9 98.66 99.37 100.3 99.99 98.5 99.98 99.35

Si 2.726 2.846 2.726 2.773 2.684 2.728 2.733 2.66 2.681 2.721 2.603 2.703 2.622

Ti 0.326 0.278 0.259 0.174 0.332 0.331 0.05 0.191 0.176 0.166 0.144 0.132 0.289

Al 1.514 1.477 1.415 1.411 1.415 1.337 1.594 1.58 1.601 1.522 1.672 1.609 1.444

Mg 1.381 1.316 1.552 1.682 1.622 1.394 1.967 1.5 1.375 1.592 1.23 1.455 1.841

Fe 2 0.788 0.762 0.86 0.83 0.747 1 0.597 0.935 1.007 0.855 1.263 0.987 0.694

Mn 0.002 0.001 0 0.001 0.001 0.002 0.001 0 0.001 0.001 0.002 0.004 0.003

Na 0.02 0.028 0.032 0.032 0.049 0.025 0.012 0.021 0.009 0.017 0.034 0.026 0.058

K 0.862 0.871 0.94 0.907 0.89 0.91 0.933 0.955 0.982 0.965 0.968 0.914 0.879

Sum 9.631 9.587 9.792 9.816 9.745 9.736 9.891 9.846 9.838 9.842 9.917 9.831 9.835

XFe 0.363 0.367 0.357 0.331 0.315 0.418 0.233 0.384 0.423 0.349 0.507 0.404 0.274

(e) Garnet (Ga)

Vn355 core Vn362 core Vn362 rim/bi Vn363NL core Vn363 core 414-S4 core Vn414BNL rim/qz Vn414BNL rim/bi Vn414BNL rim/spl Vn413 incl in pl Vn415 core Vn803 core Vn803 rim/qz SiO 2 38.000 37.290 36.990 38.330 37.860 37.470 37.270 36.770 37.370 34.840 37.990 37.770 37.790

TiO 2 0.050 0.050 0.070 0.050 0.040 0.020 0.010 0.010 0.000 0.010 0.040 0.060 0.040

Al 2 O 3 21.840 22.380 22.150 22.170 21.810 21.560 21.390 21.210 21.550 22.350 21.790 22.080 22.120

Cr 2 O 3 0.000 0.010 0.040 0.020 0.030 0.000 0.000 0.010 0.020 0.100 0.010 0.020 0.020

Fe 2 O 3 2.270 2.990 2.510 2.280 1.160 1.720 2.110 2.180 1.420 1.290 1.840 2.100 2.290

MgO 7.540 8.370 5.790 9.540 5.800 6.430 6.070 4.620 5.150 3.640 6.530 7.770 7.780

FeO 30.750 27.340 31.460 26.740 32.740 30.840 31.170 33.060 32.930 32.610 30.210 29.110 29.370

MnO 1.010 0.480 0.800 0.380 0.540 1.540 1.480 1.490 1.470 1.840 1.900 0.560 0.580

ZnO 0.020 0.000 0.000 0.040 0.000 0.000 0.010 0.000 0.060 0.000 0.000 0.030 0.060

CaO 0.170 1.440 1.220 1.310 1.270 0.720 0.810 0.810 0.790 0.390 1.320 1.260 0.960

Na 2 O 0.000 0.000 0.000 0.010 0.010 0.000 0.010 0.020 0.000 0.040 0.000 0.010 0.030

K 2 O 0.000 0.000 0.040 0.000 0.000 0.010 0.000 0.010 0.000 0.000 0.000 0.000 0.000

Sum 101.660 100.360 101.060 100.880 101.260 100.310 100.330 100.200 100.770 97.110 101.630 100.770 101.040

Si 2.936 2.888 2.900 2.932 2.959 2.949 2.942 2.937 2.953 2.873 2.947 2.927 2.924

Ti 0.003 0.003 0.004 0.003 0.002 0.001 0.001 0.000 0.000 0.000 0.002 0.004 0.003

Cr 0.000 0.001 0.002 0.001 0.002 0.000 0.000 0.001 0.001 0.006 0.001 0.001 0.001

Fe 3 0.132 0.174 0.148 0.131 0.068 0.102 0.125 0.131 0.084 0.080 0.107 0.122 0.134

Mg 0.869 0.967 0.677 1.087 0.676 0.754 0.714 0.550 0.607 0.448 0.755 0.898 0.898

Fe 2 1.987 1.771 2.063 1.710 2.140 2.030 2.058 2.208 2.177 2.249 1.960 1.886 1.900

Mn 0.066 0.032 0.053 0.025 0.036 0.103 0.099 0.101 0.099 0.129 0.125 0.037 0.038

Zn 0.001 0.000 0.000 0.002 0.000 0.000 0.000 0.000 0.004 0.000 0.000 0.001 0.003

Ca 0.014 0.120 0.102 0.107 0.107 0.061 0.068 0.070 0.067 0.035 0.110 0.105 0.079

Na 0.001 0.001 0.000 0.002 0.001 0.000 0.001 0.004 0.000 0.006 0.000 0.002 0.004

K 0.000 0.000 0.004 0.000 0.000 0.001 0.000 0.001 0.001 0.000 0.000 0.000 0.000 Sum 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 XFe 0.696 0.647 0.753 0.611 0.760 0.729 0.742 0.801 0.782 0.834 0.722 0.677 0.679 Xalm 0.680 0.610 0.710 0.580 0.720 0.690 0.700 0.750 0.740 0.790 0.660 0.640 0.650 Xpyr 0.300 0.330 0.230 0.370 0.230 0.260 0.240 0.190 0.210 0.160 0.260 0.310 0.310 Xgro 0.000 0.040 0.040 0.040 0.040 0.020 0.020 0.020 0.020 0.010 0.040 0.040 0.030 Xspe 0.020 0.010 0.020 0.010 0.010 0.030 0.030 0.030 0.030 0.050 0.040 0.010 0.010 (f) Cordierite (Crd).

Vn413 crd1/bi core Vn413 crd1/bi rim Vn363 crd2 core Vn363 crd2/ga rim Vn414-1 rim Vn414-2 crd2/sp rim Vn414-2 crd2/ga rim Vn415 crd2/ga rim Vn415 crd2/bi rim

Table 2 (Continued )

(g) Prismatic sillimanite (sil)

Vn353 Vn362 Vn362 Vn363 Vn414.S4 Vn414.S4 Vn414BNL Vn414BNL Vn413 Vn415 Vn415 Vn803 Vn803 SiO 2 36.1 39.73 36.24 36.41 35.62 35.84 35.94 35.13 34.95 36.42 36.24 36.3 36.16

Al 2 O 3 63.92 60.1 62.93 63.96 63.99 63.83 62.85 64.04 63.37 63.22 63.22 63.76 64.01

Cr 2 O 3 0.07 0.02 0.04 0.05 0.03 0.03 0.03 0.02 0.02 0.01 0.06 0.04 0.06

Sum 100.45 102.74 100.61 100.81 101.07 100.99 99.85 100.02 99.52 100.64 100.77 100.44 100.86

Si 0.972 1.05 0.977 0.976 0.958 0.963 0.975 0.952 0.953 0.98 0.975 0.977 0.97

Al 2.028 1.872 2 2.022 2.028 2.022 2.011 2.046 2.038 2.006 2.006 2.023 2.025

Fe 3 0.004 0.039 0.024 0.006 0.026 0.022 0.02 0.016 0.023 0.018 0.024 0.005 0.011

Sum 3.01 2.995 3.01 3.008 3.015 3.013 3.009 3.017 3.016 3.008 3.009 3.008 3.01 (h) Ilmenite (il)

Vn363/sp2,

crd2 core

Vn363/crd2 rim

Vn363/crd2, sulph, sp2 rim

Vn414-S4 in crd2/sp2 rim

Vn414-1 in crd2/mt, sp core

Vn414B matrix

il rim/bi

Vn413/mt core Vn413 incl in

mph core

Vn415/bi12 rim

Vn415 in crd2 rim/sp2

Vn803/ga rim

TiO 2 54.83 50.7 51.03 51.01 48.86 50.66 47.47 46.89 49.69 49.61 53.12

Sum 103.27 101.79 100.2 98.1 98.42 99.97 102.52 97.26 99.04 99.7 99.34

(i) Magnetite (mt)