id Assisted Recrystallization in Upper Mantle Peridotite Xenoliths
Transkript
id Assisted Recrystallization in Upper Mantle Peridotite Xenoliths
Ú :tL Le .EJ id AssistedRecrystallizationin Upper Mantle PeridotiteXenoliths from Kimberlites E--: AND H. L. M. VAN ROERMUND by M.R. DRURY* of StructuralandAppliedGeology,Instituteof Earth Sciences, StateUniuersityoJ Utrecht,PO Box 80.021,3508TA Utrecht,The Netherlands (Receiued5 January 1988;reuisedtypesuipt accepted 18 August 1988) A BSTRA CT development of recrystallization microstructures has been studied in some 'hot deformed' xenolithsfrom the Thaba PutsoaKimberlitepipe in S. Africa.The xenolithsweredeformed strainsby dislocationcreepin the uppermantleand thenannealedas theywereupliftedby the ffuid. Static recrystallization occurs during annealing producing euhedral shaped'tablet' Tabletgrainboundariesaresub-parallelto crystalgrowthhabitsin olivineand orthopyroxene. grain boundarymigration, nicrostructureis characteristicof recrystallizationby fluid-assisted a thin fluid film is presentalong the boundary. lhcre is microstructuralevidencefor a complexfluid infiltrationhistoryinvolvingan early Fe-Ti ctasomatic silicatefluid and laterkimberlitefluids.Minor partial meltingof clinopyroxenecan be inferred,which,is consistentwith infiltrationof a kimberlite-derived C-H-O rich fluid into the hs.Any ofthesefluidscould havebeenpresentalongthe tabletgrain boundariesduringstatic allization.The occurrenceof tabletsrains in 'cold deformed'xenoliths,which have a simple history,suggeststhat a C-H-O rich fluid derivedfrom kimberliteis the most probable fluid in both the hot and cold deformedxenoliths. Tbe occurrenceof dynamically stable semi-continuousgrain boundary fluid films during rezationindicatesthat mechanismsof fluid segregation and transportin the uppermantleare to be dependentupon the type of deformationand recrystallization mechanismsoperating.In the destabilizationof the static fluid distribution by grain boundary migration and tion will alsb influencethe rheologyof the upper mantlewherefluids are present. INTRODUCTION Kimberlitepipescontainperidotitexenolithswhich representaccidentalinclusionsof the qper mantlewall rock of the kimberlitemagmaticconduit (Ahrenset a1.,1975;Boyd & (Z) estimates(Boyd & Nixon, DÍeyer, 1979;Kornprost, 1984).Pressure(P) and temperature Finnerty& Boyd, 1987)show that 1975;Carswell& Gibb, 1980,1987;Bertrandet a1.,1986; úe xeno|ithsare derivedfrom depthsof 70-250km, so theyrepresentthe deepestsampling ď the upper mantle that is availablefor direct study. Many peridotitexenolithshavewell developeddeformationand recrystallizationmicrostructures(Bouillier & Nicolas, 1973, 1975).Two types of deformedxenolith can be distinguished on thebasisof P-Testimates,bulk compositionand mineralchemistry(Harte, 1983).The cold deformedxenolithsgiveP-T estimatesof 3G45kb and 800-1000"Cand havesimilar(basaltdepleted)compositionsto the commoncoarsegranularxenoliths.The hot deformed xenoliths give P-T estimatesof 50-70kb and 1200-1400"C and are *Present address: Mineralogy Research Centre, Research School of Chemistry, Australian National University Canberra ACT 2601. 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Polished thin sections were examined at 20 kV in the electron image mode in the SEM and ion beam thinned foils were examined at bacn hcÉr. P ER I DOT I T E P ETROGRA P H Y bot deformedsamplesstudied include a partially recrystallizedporphyroclastic mosaicporphyroclasticxenolith(DACIDAC-L22)and a completelyrecrystallized Tbe nomenclatureusedis that óf Harte (|977\. bolith DAC-L2? has a porphyroclastictexture(Fig. 1A) with a weak lamination by modal variations of orthopyroxene,clinopyroxene and garnet, and also by of the amount of olivine recrystallization.Bands with higher content of other have more extensive olivine recrystallization. A foliation is defined by the modal ion and the preferredshape orientation of inequant orthopyroxene and olivine. r the occurrence ď r,rhich grow into tbc lber. 1976;Gueguen 19.-ireuhedralrecrlhadon of Srcchronometer', to !Bó: Urai et al.,l98ful h recrystallization lL l98óa). In this y. and migration occurt d precipitation of the ůkh aims to investigate . rat of the tablet grainr d tsallization mechanisms fo ms can have an imporrat nd grain-size palaeopio D to the upper mantle (Ar atge of the recrystallizatim t_ l98s). nribution of fluid phasesir ,ohlstedt,1982;Cooper & :nan. 1987).The physical I the rheologicalproperties m studieshave considered & Bulau. 1979),or during L 1984).Far less is knswn plasticity or undergoing relativelywell constrained : peridotitesin a fluid-rich C -I ,&- Ftc. l. Microstructures of peridotite xenoliths. (a) Partially recrystallized microstructure of porphyroclastic xenolith, DAC-L22. Scale bar =2mm (b) Completely recrystallized microstructure of mosaic-porphyrpclastic xenolith, DAC-L?7. Scale bar: 2 mm. (c) Primary orthopyroxene grain in DAC-LZ2, showing rim of secondary clinopyroxene Scale bar:400pm. (d) Corroded margins of primary clinopyroxene grains. 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Olivine nt- large (1 5 mm) r Éatures and exteffic lt t}.p€ orthopyroxer 2-l0 mm in size'whiÓ tn-subgrain boundari ůe primary SP i n e l Al Cr Fe e obtained on this rim d Na/Si ratios compard n1- clinopyroxene occutr ccrvstallization. These d electron images are li Ti mber. This is consistent r of Na and Al in polyphasereactionrim. Tb D thosedescribedby Reid & ústsofeuhedralspinel,Ti rkh rerpentine. In the partially he olivine tablet grains.Tbc frases (Fig.2B)'eitherspinď nd amphibole.The grain sizr iling into a very fine grained spinelshave lower Tmplectite rmphiboleshavelower Ti, IL nhs are qualitativelysimilar neoblasts,and orphyroclasts, much smallerthan in the hot res showsstrong undulatory Bands of Ď|ast development. bng the foliation defininga cscriptionsof cold deformed IN OL IV IN E n the porphyroclastic xenolith aight sub-boundaries parallel of cumulative misorientation res developed are described in ure consists of closely spaced attice tilt rotations (tilt walls), c iffira a Garnet reaction rims (a) Light micrograph oÍ polyphase reaction rim' showing decrease of grain size mr*ards the garnet interface.Scale bar = 400 pm (b) Line drawing of SEM backscatteredelectron image, showing !@qÍs€ outer zone of spinel+amphibole+phlogophite and finer grained middle zone of spinel+orthopyroxene +anher clinopyroxene or amphibole. Middle zone clinopyroxene and amphibole can only be distinguished by ffi\ spectra.In the middle zone of individual reaction rims the occurrence of clinopyroxene is mutually exclusive m m ,u n ph ibolea n dviceversa. S cale bar:60p m. (c) Qualitative EDXspe ctraob taine donthe S EM, ofthe pha ses shown in (a) and (b). uith a moderate to high density of free dislocations (1011-10t2m-2) between the walls iFig.4A). In addition to this 'background' structureother structuresare locally developed {Drury & van Roermund, in press) including healed micro-fractures which are defined by planar arrays of multiphase inclusions. The free dislocations and some healed microfractures are decorated by three phase inclusions,0'2-0'1 pm in size,which contain ilmenite,an amorphous phaserich in Si, Al, and Fe with minor quantitiesof Mg, Ca, and Na, and a portion that is a void or a fluid filled bubble (Drury & van Roermund, in press).Some healed microfracturesare decorated by another type of inclusion,which is usually filled by an amorphous single phase.This phase did not generateany additional strong characteristic EDX peaks different from the matrix olivine although there were traces of K, S, Ti, Cr, Ca, and Cl. A few of these inclusions contained a crystallinephase rich in K, S, and Ti+(Mg, Fe, Si). Numerous larger scale healed fractureswere visible by light microscopy. Many of the fractureswere decoratedby strings ofopaque blebs parallel to the trace of(100) planes in 'ul€ l a .,n,.n,,,ons(J)'Állsuap Jo I?']Peá]Juoll€ J o.lst.o ^(B]J;1i:3l'j:1]']j[}"J...], uo.1nco1s'p ea4 u.n,b "qlJ9""]]1".d . ..l;';;il,;Jl[Ťj'Ír.o1,;:.".ů'xff,!".''l",. '.J"^dxxi;l;;;;;' ,::x"#ff,;j:l.'u ;.*,'.d":iií:;f 'olq€ ' '€ ',:'i]:il;ó;; - ^ rpr (001) 8ur't'roqs'1st1co ml;iT:j]Ji,lnx'iliTJH]'a";T,: uÍ{9.l ď #,-- . \ F \-š r oql urp : 8 t : . _. -q r \\o qsslu e r u . : - :. . lpaqn0 0 ql J (r : _' : \llJ U l l s t p lsoLL : ' ] -' !. - I o otu os .S uol]ť .. ' : - r u ollpl u O uO pAli:_-_. _ : _ : l ' i s PJ L l .t u otlcluJ::,. t [8 uB uorlElurtj . .; :' ::' . r il r sue p tcejep _: _ -.-- t r q ns SnOeuOS OLu._ . = g .l olJ O Á s:e8:ng u. :- : j] qll,tr .s1se1co.lÁqd. : _:- - . s uotle col srp olqPrj: " . . r i r ppun oq lq Brurls e,, . : -. -' r ol iqdr od oql pun(. -:-: : t s P I qoou 0 ut^ rloor]J ;. 4 ) f d -'qt acue8ur{oJrgJe,rol ; - - l Eql Surlec r pu,re u r n r l o 'tse 1colÁ qd rod p oulJ oJ opp loo J o olnlsnllsolJ llN 3ur'toqs 'S l0t C lg tllllouox su rerB 1s1qv1 le rp e qns pedole,n a p - roJepu t *-v)YI óiů* ,t. I D lc DEF OR M ED P ER I DOT I T E X EN OL I T H S 139 ,Jicatingthat they locally decorate(100)sub-boundaries.The fracturesoftenhave a r,::irinsence than the rest of the olivine. R E CRYSTA LLI Z A TI ON M I CROSTR UCTUR ES N eoblasts TÍe 2 O OFm L :. rlet gr ai ns d ev e l o p e di n d e : : - m u u t '.lírineneoblastsare polygonal,optically strain free small grains that occur in bands iiuillr'rir".urrl,; rhe porphyroclasts of the partially recrystallized xenolith (DAC L22). The grains llllllltlur',Lr: boundarieswith numerous near 120"triple points.TEM observationsshowed '::aight [lWj]I u]rČdislocation structures (Fig. aB). Some grains contain similar Structuresto the with the additional developmentof (001)tilt walls made up by dislocations 1pr'":niroclasts, Lwrttr:ltt B"rrsersvector b:[001] (Fig. aC). Other neoblastsare almost defectfree or have an 111p11;l:gr$€ n substructure. eous Figure 48 shows an examp|ewherea portion of the grain with mmll.r defect density is separated from a strain free portion by a curved, moderatelnml'r.entationangle (0: 5') subgrain boundary. -:-,entationmeasurementsin bands of neoblastsrevealedstrong local crystallographic r"mr:rc:red orientations.Individual bands containing 20-100 grains are made up of only 3-5 iřE:tetions' some of which are close to orientationsof adjacent porphyroclasts. Tablet qrams Tre most distinctive featureof the partially recrystallizedmicrostructuresis the develirr:int of the euhedral to subhedral shapes of the tablet grains (Fig. 5). Universal stage .lr]Iřůsurements show that the orientationof many grain boundariesis relatedto the |atticeof Lrne tablet grain. The most commonly formed orientationsin olivine are {010} and {110} :;-.:. showing (100) tilt walls with a ]€ : .]eous Substructure in neoblast A : - - ' :na por t i o n w i t h h i g h d i s l o c a ti o n , l . :ilt w al l (h o r i zo n ta l )a n d two ( 1 0 0 ) L].ťi sraln Ftc. 5. Light micrograph showing cuhedral olivine tablet grain growing into a deformed porphyroclast. slsPt3oriqdrldp fl I s-eJlrua y mr B eiEq ol rPtrr aqt qlli .!*Tllu|sa^€ q slelq€ t pu€ sls€ l qoou egl .uoIl?IIoJoq] ol J€ I nclpuedred-qns eq ot F[PJBd-qns eq ol II0o] pu? [00l] JoJ Ácuepuel B e^€ q Sls€ I coJÁqdJod eurlr1o eql Jo sIsÁIBu€ I€ c IlsIlB]s € pepnlceJd slsElcoJÁqdJod eul^Ilo aql Jo aZISaEJBI fr1t a8utsI?sJe^Iun€ Eulsn peJnsueu ueeq a^€ q 1e-I-Jvo, qllouex cl1selcoJÁqdJod i1erged eql uI uIBJE eul^llo Jo sedÁ1eoJl{l oql Jo suol}BluelJo ácll1el eql sNoIIVINa I uo C a uua . { a ud J I HdvuDo . I . I V J S Á uJ EF=])lqer ]}E:fá lF l5.!La rea.n. po:l".o'ň rrrEJd rrqdu.Ř1ri,i.fr s .soseqd Áretptsqns JouIuI uI peulzluoc Á1qeqord aJB qclq/t\ .eulluodJes ) Jo sellllu"nb lptus pe^\oqssPeJÉeul]uedJes eql Jo € J lceds Xoa í1od1o turu lclql ruť 0I-l u Áq paugep aJB setJepunoq utur8 láIq€ 1 eqlJo IIV .saJnlc?{ pelBoq Jo ee{ eJ? SuI€ J E eul^tlo eql soJnl3nJ]soJctlu Í.i' irrer Á1e1a1duoceql q .Lz.r)Yq, qlllouex ut eJnlcnJlsoJclu clesol'u euI^IIoaql I st eJnlcnJlsoJcllu stt{J .sut?J8 IBuoEÁIodpezls tunlpelu Jo ál?EeJEE? pgztlplsÁJc u úq pece1der Á1ele1durocáJB suluJ8 1se1corÁqdrodzzl-cvq Jo s€ e J? oluos uI .seJnlcu4 páIuotl Eut.,lrorEra'roÁ1luereddz surerE 1a1qe1 pue sure;8 1s1qz1 Jo l ssqcorÁqdrod qEnorq1 Eutllnc ssoJc seJlucu{ Jo punoJ eq uec se1duexg .selJepunoq .suolsnlcul aql put SeJnlce{ pel€ o q eql ueo^\leqSJncco sdtqsuot1u1ar.;o eEuer V tu uoJc|Iu-qnspuB seJnlcB{ pel?eq ;o Á1rsuep,!\oI? ul€ l uo3 sutBJE lelq€ l oqJ .sls€ I coJÁqdJod .selJ€ p unoq st ÁrleuoaE sIqJ dreqs qltnr u pado1eneplzql ol lueJaJlp Á1e1o1druoc seldurcxe aJBJ uI uter8qns;o mdqns aírc1g-7 olur popr^rpere suter8 1a1qe1 luerudole^op a,raputur8qnsou Á1ureue8pue (q7 .Etg)suot1ecolslp [0oI] : q ee{ Jo (. - tu o' _0I ssa1)Á1tsuspnro1Árel 3 poul€ l uoc slolqel euI^IIoeql leq1 pe'tol.{ssuolle^Jesqotr^trgJ '(q'Ers){orr} .{otz}.{t do1anap leql suolluluelJoeqJ.suoll€ l ualJo cqdurEo1u1sÁrc 1p ;I Iz} 1g}spn1cur qp..r sauupunoq o^et{osIB 1z-I1vo qlllouax ut sulurE lolqul ouoxorÁdoq1roeq1 '\tL6I) ulqll^{eq punoJs3 .1selcorÁqdrod aql ut [too] lo tl!rr|\{ T' JotlltnogÁq Á1snorrrard "0€ _ oz ueemleq puu 1e1qe1 eql @ulalqel eql ur [169]ro; Ácuepuele ro; ldacxe.sutztE1se1corÁqdrod .punoJ ou osle eJe.t\ eJeql selJ€ p unoq rúqsuor1e1e; uoll€ l uetJo eclll€ I peugepilá1y\ lou eJe^\ uoll€ l uelJo o1dtutg mer8 1a1qe1 aql puu eclllĚIlselcorÁqdrodeql uoo^ueqsdtqsuot1e1sr .[oot] Joqltepeul€ l uoc peJnseeu .uoql uIqlIA\ [too] lo [oto] .{ozt} .ElJ Áq luelxs Jessol€ ol pe/\\oIIoJ (q sr'Epunoq 1s1qe1 1qEre4slsol^tr {zot} pun.{tzo} arl*l|o JoJ.'I'JE lelq'l oql Jo octll'l ol lcsdse'l;'"#;ijÍ,::li:ffinoo 0r0 uÍEI'lolq'l ro.1a.rnBgolod esJo^ul.9 .cIJ tt0 t00 01,0 oop oo oo ood rEr 3 N lX 0 dA do HlU 0 o N n hluao u Nv^ .^ ..I .H r00 tzj o o Llf o a ]NIAIIO CNY Áunuc .u .^ 0rl DEFOR M ED \D IUL IE\: '. t41 X EN OL I T H S P ER I DOT I T E oo \ ?4 n }.ý ^\. 010 llr'=:e lst ..f the tab|el gratE- ÍúŤ slpi*1t1 1u61., I cl iattice and the tablet lrrr-e o rientation relati lncl for [001] in the tabb riousll by Bouillier & \i ! alw have boundaries ru& r l u de l0l1 ), {2 10} ,{21l : d d a ren'low density(lessthmr ďl1 no subgrain developrntmniled into 2-5 large subgranr Gnt to that developed in h. s and sub-micron multiphas zlaj fractures and the tabltr g through porphyroclastsinto caled fractures. mpletely replaced by a rer microstructure is identical to t the completely recrystallizď *ď! ->:1_ "4 .- Ó ( D- !L n thick film of polycrystalline nII quantities of K, S, and Ti or of crystala|9 91ie,nja]191s projections Lowerhemisphere orientations. preferred Ftc.7. Crystallographic per 4,8,12,|6'20o/, porphyroclasts levels: iontoui orientation. foliation tr'. great .i,"ů,^t'o*' Thedotted olivine. lobarea(25grains)Jtablet e,^;ii1,1,Á,e,*'iu'ío#.iil',í:.area(100grains);neoblasts,|,2,4,6,8,10oÁperIoÁ II E \ T ATIONS r in the partially recrystallized g a universal stage(Fig. 7).The anal."-sisof the porphyroclasts. ll to be sub-parallel and [010] tablets have similar preferred The recrystallized orientations with the main maxima close to those of the porphyroclasts. as found porphyroclasts, the than preferred orientation diffuse grains appear to have a more effect owirig to the small Ěy souiilie. & Nico1as (I913).This may, however, be a samp1ing number of porphyroclasts measured' lrll] JqtJo lno palselJ s f_*trta uuncco ipo & P't"tot ri q"rq^rili' +-*fi,"'#,?,ilH ;1fl:',"":TilTn:* I r JJ nIB [a^ t t P1 n * n " r.r* EFloeu pezr11z;sÁ.lcer sň JD IIIsru?qJaIutuaudola."q F uJoJ slelq"l leql uorlp^Jesqo eql qll^\ paulquoc 'srql 'uorlelndod uorleluerJo pcol oql ut luaserd eJB suolleluáIJo lelqq eql letll rrtoqs(1 '3rg) s1uerueJnsueul aL .(LL6| .uanEeng) uor1uzqp1sÁrcs.rcturuuÁp Áq peurro.;Á11et1tul eru Áeqt leq] (c .gl .El.t)s1stlqoau eql uI eJnlcnJlsqns uollscolslpJo uoIlBIJ€ ^ eqJ .uoll€ u JoJáp uot1ezq1e1sÁrcalls€ I qoáu roud ;o ocueJJncco aql Jo esn€ c oq ssecord xs1druoc fuquauuu uoll€ I uJoJop-1sod Eurrnp Slelq4 euwlo Jo 1ueudo1anepoql lgttl Á1s1r1sr 11 surcú p1qv1to swstuoqcawruautdo1aaaq E ncslp P ro1 199961,.1op rclnig86l os a! sb/ zv e{l u! t'lJ^toJ8 Áq pouru1ds ótl sEloJIN T' Jall[Inog FB .(ÁEo1oututra1 uot1ezt11e1sÁrcor ^Ip1a Árnrq ees)ustueqcau q1rrrort1uenbasqns 'srrrJoJlsJg urer8 ,rau eql oJeql\ rusruuqJerulueurdolsnsp JerlruruB Jo sruJal ur eq III.lrr' slusluuqcaul uot1ea1u1sÁrcoJ eI'IJ .peJeptsuoc ueaq a^eq suturE 1a1qe1.;o eql ul po^lo^ulsusIuBI{3eI.!aql Jeil" pessnJslp eq ill^\uoIlEJuUuI plnuJo Áro1stq 8uttut1eqJ .sollloplred aql o1ut seseqd p1ngJo uoIlPJlIguI puz uotl€ F p qll^\pál€ l coss€ gepcllse1d/e1lllJqJoseEuls ute.rlsll€ t us eJolu Jo euoJo ecuáJJnccoeql seluJlsuotuop c pepeq ;o acuese.tdaql uorleruJoJepe[pnp ururls a8rel egl ol uourppu uI 'GL6I lr.ny1 i1-261.usntang) uollel'uJoJáp Euunp uot1uzt1e1sÁrcsrÁq poIuJoJ Á11ut1lut erem &qt teqt smoqssururElsulqoouaql Jo lsou ur seJnlJnJlsqnsuorl"colsrpJo ocuose.rd eql '(6161'rarcra61) trnpuoc neurEeur eqlJo {coJ II"Á\al€ I petuut eql Euop Jo.(€ 8 6t .a1ru11)ÁpoqeuEuru Jo (€ 8 6I .'Á6I lsnEang ry uearg) rrderp e go sdolenua crlsuld eql ur Jeqlre 'ssoco.rdcrluruEeurolllJoqrur{ rg1 o1 Áulr oulos uI paleleJ Á1quqord sB^\st{lllouax loq aql Jo uoIlBIIIJoJápáqI (z86I :aoJJ d' o1.tug)uollBuJoJep Jo suolllpuoc eql ol pel?IáJun pu? uI uezo{ oq Áeul Ár1stursqc pJaulu ásotl^\sqlqouex peu]JoJep ploc áql JoJ enJl eq lou Áeru stq1 (t86t .pÁog T íuauurg :tgo t .qqtc T, IIe/nJBJ1986Í,'lo ia puelpag) Ár1stureqcJ€ J ouIu aqt Áq pe1uctpuleJe uou€ l llJoJop 8urrnp srnleredrusl pue srnsserd eql squouax poulJoJoploq oql Joc .ellu€ t u raddn aqt ur. nlls ul ureJls a8:u1 o1 peuJoJep eJe/h selrlopued eql oEuqesuue ol JorJd .{coJ II€ ^ \ elluptu peulJoJop loq eql;o sern1uredua1qEtq eql l" sclleul1 uot1zzt1p1sÁrcer ptder eql Jo esnuceq penreserdeq lou plno/h seJnlcnJlsoJcll'uuolluluJoJap slÁ\Jeqlo .1;oqsa1tnbaq lsnu porred slql sglqouáx peluJoJep loq eql Jog 'sq1llouexeql Jo |uel'uul€ J lua puB uolleuJoJepJo uollBssec eql uaá/t\leqporrad aql uI peJJncco osF Eut1eeuue .uan8ang ,rctcls6) plng olTlJequt{ tuqt e1qtssod sl 1t qEnoqlle .(€ 8 6I T' ueeJD i6761 oql Áq lrodsu€ J l qltlouex Euunp peJJncJo e^Bqllvrr Eutlesuue eqlJo qcn1lr{.(9961.usnEeng .rarcre61i1'1-61 ,uanaans) :st6I .su1oct51 reqpnog) 8ut1uouueuoll€ I 'uJoJop T' ueeJc !6161 ry -lsod Euunp 'te.rt Ásql l€ q l seleclput suter8 lalq"l eql Jo aJnl€ u ae{-uleJls eqJ st4lrlouaxlo [.ro1sn4ID)ruDq?aw-owrag NOI SSNJ SI O .surer8 1su1corÁqdrod;ouor1e1ndodpcr1sr1e1s€ eJns€ e u ol oIqB eJeA\oq^\(9161)su1oct51 JoIIIInog Áq psure1qo ueaq e^Bq slFsoJ a1qereduro3 .ssrn8g e1od [g1g] pue [691] eqt d' uo Jncco scIJquJ1su1corÁqdrodpue 1se1qoeueql ol lcadssr qlIA cIJqeJlelq4 eqlJo suolleloJ JeIIIuI5'uol1€ l ueuo tsqcorÁqd:od pue 1e1qe1áql qloq Eutute1uoc.€ u Jlxetu [169] e1qnop € e^Bq sl$Iqoou eql oIIq^\.s1se1corÁqdrodeql Jo eIIIIXPu [too] eqt ruo{ oo€ 1noqe Áq poleloJ st sute;8 lelq4 aqlJo Brulx€ t u [too] eqr.uter8;o sedÁ1esrql oql uee^ueqsecuaJeglp rrroqsse.In8ge1odeql ueql .peJeplsuoceJ? suoIlBJugIJoperraJerdeql Jo BIIIIX€ I ueqt Á1uo;1 .W ..I'H cNV Áunuo .u .W oNnl^IuaouNv^ ztr
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