Document Z84MeqrZEdM2a4YZgvJ2J2zbp

.. .U*v4 MIW5RALOGICAL MAOAZIBS, r. 35, 1965 1S8 V. r. Itf** AMD o. WttUAWaOB OW BTXAtffED XA05**U IBf . jb amlyww and B.*LT. mrfarvana MMntmmte vsc* oMakwd tfamft tW Mta; of Or. V. R. Rawmm and of Dr. F. L. Waftrr roynWy. Mechanism offormation offorsterile and enslatite Aunorta (A. H). 1D99. Zoom. Proe. Roy, fW. Bov AoA W,to. oof. tf, p. ft. ' from serpentine . Bajui (U W.), H*ot.ww (I. It.). Mosamov [J. A.), and Rvdmam (R.X 1000. Tran*. Fwadny Ibr.* vo*. 6*. f. DDT. B. 0. W. B*i*dut, MB., Pk.t>, mi Rtozo Kataxi, XB. )bl*t (9m Okoook). IDS!. AiPfttlen and Row of nlMii UnAm. XwoRka ndCb. gainnr (ft T) **** WA tlofc, tVpaHmm* ofCWtobTn.lmfetf, Raaiy(. KAten.1. RoeAixb Labor.to^. T\s P.nr.._!,.ni. Stmt# Vnivenotr, Vainmtf Pmk. Pmn^lraoi^ UB.A. rank 8Uto t'otvonfkj. PaiFMir (0. V.). I96t. QunMltallr# wwlpalo of elsy olikm, Di). XtV f > fpmi 14 immtj IMS) tli X-fy MrntWulloa and erjoia) itrwtw of tUy aionk', adltod ky 0. Brvva. Ktorrafaftcat Sodity, London. ItBetl (If. /,) and (E.i, IDS?. Amor. Via* *d. It, p. 9*. . Daetiut (f.) ood Rot (R.J, WW. In 'Rnetivlty ^ SoTida', edited 1/ J, H. toBoar d glnHif, AmoUfdam. p. 8C2. lotMM (9.% 1*9, Dbcin. Fa*adap (far., Bo. 9, C*7*ft*1 Ofovtb, p. lit. Fees (W. 9.X Tvanaa (F, /.). and Yaanoooaw (J.), 1969. Mitiaiirpkk mrtba aod mtawnrpfdn farlm? <Jot. Boo. Amt. Momotr TJ. Omaoo (9. J.). 1*88. Active Wid*. Dap. 18 of *9orfaro Pliaamwa la CWokby Md Btotofy*. odltod ky J. F. IXnlalll, K. O. A. PanXXn\ and A. C. Riddl- l*d, N|tow Pim, Kv York. . Oasoos (D. T.X Fatoooo* (If. 9.), Hbaso (It. C.). and Te-asta (F. /.). tMQ. Awavy. Fowtorlla (grind fmo mpoiko pordaro at *ai4o-- traparataro p to *00* C two toon maaaaiad (natltolWy tip X-ray dlfmctfeta. TW mWta am moildarod la rotation to n tntlloo nntawhn piapooad If Ball and Taplor and an alonn to la tewnldnH vfll tW doUTIa oftlfa nwtaahn. AnaBamatlro mrlantoo b piupaaad If tkt allar aoarfpall tba V(tomtofatW *9% aomaof tW 81 tono tliarsUd In tka raarthn aoaoa vkars vstar la form ad *%rto Into iBjlaar rksra brstoHte It farmad. TXIa wrtlawlaaa la In rfcaar neeord old tto OMpadnmtal rsaotta. Tlo rotardad dttalpnaol of anatoUto mill tsmpomtow aboro HfiO* C oro wad I attrdotad to tk* natnro of Ibo naeUoo If vblcb It I faamad, namolf a ronctlon totoaon femtoHto and adtka. Dap. S. XkI ZMbnaatlon, odltod ky D. OHgo and /. Pndkv Goat. See. Aao^ iitm, TD, p, II. KaPMU (/. L). 1*91. UJ. thaab. Impartwont of Omni* T*Aaoh|y, Promptvanla 9tata Vlt*nHy. HE <dhji!rtion and nkaeqMut rrcftiUHiiitlw of orpeatio Tmioerati, both pUtr and 9brof forma, ktvt beet tbe Mbjoct of BWBmooa iBTcatfgaUoaa.1 Tbo pnoctpot rcerraUQiaitiofi prodneX Hami (A.X 1*80. MatamorpAbm, Srd adn, London. VoUoan and Cb. laaan (W.) d Wvoaca (J\ 1*19. Zak, anorf. Cham., vof. SI, p. SXS. KoCOora (W. CX ***. Woo*, ftndty Boo,, Bo. 8. CrpcUf Omotl, p. 159. Ifum (O,) and 9cuott (W.). 1W8. KolWd-ZaUa^ rl. . p. t. focotonto, m fonM topotncticnTTF, le.# Ub wott-deftoed etroUliofropbio omotntionA with wpoct to tbo paroot erjotat ttroctoro. Ceondenble hiUreot baa bora tabco *a poaaibtn onaebaabaBA bf wbieb i -- M ItfS, Bar. doit knw. Ota, vot. 99. p 199. _________ and fiances (A.X I9DL 1M.t p. 290. Pittn(L. H.V I***. Trano. Dm 9oe., vol. 108, p. 180*. Baarooui (L. P.J. 1D99. Btmnk, rol. 13, p. 944. tbaaa topotasbl raUUooa t dtrtlope^. aad Zawnaa (1957) itodfoi a pfatr form of aarpoatio*, (ioirttite, aod Interpratad their data lo tarsia of a homo^tnaotta reorgaoitatioo of cattona witbia a target/ 8al*n (J. F.) and Kcuti (F. A.), 190S. Zoom. A*"or. Cna. 9or.. rol. 48, p.16*. 8eiinu (/. r.). 1937. m/.. rol. 40. p. 115. 8lA (X. C.X 1*19. Jonm. Appltod Moebnln, rol. 18. p. 37. oooatnnt oz/geo framework, with no expesfaion of 8i ions it excess of roqairamaatB for tb fortnatien of forsterite. Mots recently, DsU and Taptor (1981, 1963), Taylor (1961), and inde- 9mm (J. V.;. 1*59. ArU Cff*t,,13. f. 51*. paadeatftr Brindto/ (1P91, 1963) bare suggested that more satisfactory Bvasao* (H. R.X Rcrat (R. K.), and Vnaiwtc (0. V.). 1**l. ftuadatd X*Rap dlffiatUon povdrr pattern*. Bat. Bor. Btofa, Clmdar 63*. *ol. ftI. explanation* for tbb and for other topotactic reacteona m brdroxidea, 09 ---- and Tatoi(R.X 1*83. |W,, rol, !. ailieates, and other materials can be given m terma of Arfrropmmas O Toanta (F. J.), and Ynmmnn* (J.). 1000. fgnonaa awl MaUamrpAW Ntrufagp. rather than Aowogroeoas proeesaes. Reactions initiated at favorable o o 2nd adn, N*r Tori. McOraw-Hl!?. Wiuiuno* (VC. O). 1WW. Jmvm. Appl. (lien*., *J. I, p. 941. sites such as external surfaces, dislocations, &e., are maintained by Yoootoa (K.X fcc***?* (*.). and (.<*<; (K.), into. Art* IrttAwflr*, vol, t, appropriate diffusions of cations up to and away from the reaction front. <j> Ml. Oabydroxylation of a mineral such as serpentine may proceed by *> (FMwn'pl ftfirvi 14 Jmnmttrp 1941.J 4 migration of H* tons to a reaction sit* where water is formed ami tn * Ball and Tsffar (t*6| flrt rvtVrmrr* to rartlrr atari. PRODUCED BY FORD l,V\>Tk .y.PPnjs'-pm. IIaa.I ..uiumwi 191 *vS* BWB f iiHaij* 0.v **> . riSSf-v -ft?.'- J-/. v .y-t SC. SCF-FA-5602 9i.m L -j PRODUCED BY FORD r JO o o o o V* <? w <>S `I!? H'llj ESMMMmU ton 0. *. liMR kr> X. Y*TI n KKfnitr>(, *ilN a fNftrr*** fn^w^w **f #*>W nttMiw, Hn*' m! Kl'^ f,, maintain r!cetrie*J nerrtrsfity. B*9 end Taylor (1009> hem given a detailed de#eriptkm of the betem* fsneoaa prccc--< by which the dehydroxytetion and fectyetaNtaatio* of terpentine (both chryaotile and ptety forme) may ub place, They ooaaedcred the formation of foreterite and also, at higher temperatures, of Mftib'tr, and, onder hydrothermal condition#, of talc. Ahbo|H lb* cryatattograpYte relation* provide strong pointer* of lov Utm *ordered* reaction# mar occur, tboy oeareelr give quantttatin Information. 8*ne* the reaction* probably occur on a fine ml*, poaibtr vtthtu domain! of tbe order of 19** cm m r, ft at act easy to obtain any direct inform*lion on tbe ionic (mainly cationic} nrigratioaa by which they am considered to take place. Tbe present writer# bare ought farther Information by making quantitative meaaommenta on the development of foreterite end, aa ffl bo oboen hero, tbe retail# #Ugga#t a aemewhat different aeqeenoa of event# than three postulated by Ball and Taylor. Experimental A maeeivo oerpontino from Qoebeo Province, offine grain cite and Data buff colour, vaa oed. Ko mineral imparttie# ere detected by X-ray diffraetieo. Tbe mineral appoam to bo a layered etroetam with eonaiderabW etaelring disorder. Po*dera with partiel* *t*e* to tbe range < dO, > fOCVtnoeb acreen rice were heated in air m uoeompactarf form on a tbermobataneo at 570* C for period* of about 20 boare. Prom tbe . loo of weight compared with tbe maximum lae at higher temperature*, H era# determined that tbe mineral m about 90 % debydroxylated by thi# treatment. X-ray diffraction date shoved no reside*! reffectiooa Croat nnteected serpentine and no detectable foreterite. 8ub#equent baat-treetmente were earner! ont in air in temperatvra-controffed fara pm at temperature# ranging from 490* to &Xf C for perioda ip to 100 boon. A few experiments were carded oat at higher temperature# ip to lidO* C to atady the formation of enatatite. Foreterit* waa determine*! quantitatively by integrated X-ray dif fraction measurements using boehmite as an internal standard. Fcf foreterite reflection* and two boehmite reflection* *f meeeured with a scanning *peed of * iffmin. Tb# rneltr are show#* m where tbe ameant of foreterite formed fa expressed a* a percentage of tbe weight of tbe final fired material, i.o.# aa a percentage of completely anhydrous materia!. The maximum TtA*avTMMtATmffft nr rear*anw* 191 nwotit of fnrwtrritr !nval*fwf fa aUmt MTV **,, %JT tb** aright *f tin* fafhr enhydnjo# material ami fa obtained after heating at Off/* C for pursuits of 90 bourn or longer. Th# interna! standard, boehmite, va# calibrated vitb'respect to a nearly pare, wril-efyeUTIisad. 'foaicaii1 foretsrite. Tb# latter contained just detectable amoanta of MgO and elino-efwtalite, catenated at 5 to 7 % total Imparity. Determination# made without allowance for these impurities nay be over*#tiatad by a few percent. j'HI -1 1 rxJ 1. f 1 'r l * ,_____________**r -- - # t* , M fart i* 1* j ^^ I f .1 f, 1 1` !* . .. mm m cc ha I. Wt|M pascent of fenfaAi fersd fl to 100 bm tk ImW fattoaiPf el bapfelan Ae*i la XJ. o tturt tto tW of SO % foratorit* mr Mod to to redoeod to .Soot T5 to T %. It to, otoerred ttot tto mSocfioao from tho fontorito dtrio^ from OKJontio. Toro tooodemd wits ropoet to tto frem th. hi|h-tcmperotuo-podoMd fonterito. Tto tooodotttng to opproximotitr th Mtno nrapeetiro of tto timo (1 to W toon) or temperotnro (S90 to tOf C) of tto toot-traotmest ft thro btoodeotng a ottrito'.rd to onion orjttol ft*, ood It o oorrvetion for inotromonUl Sroodrnin( i. toood on tto todoetion* from tto Ugh-tomjmrotoK-ptodond frmtmto, tton o rotoo of tto ardor of 4 x I0-* cm fa obtained for tto rryotat t* oftto fontrrito obtornod from orrpmtim.1 ff tto Scomfentng oraro portfr from faflico 11W (wmtlm ont t. Irtnonital tmtotr, b i I. "" bnWStotol thSrt.rri towof.:l . MB ;.. . .mf. *v Y\  iwiiWfn 4 193 o. w. IttWOlCT AWO *. *ATA*f Off TmavsrouraTtowo or starcwTruB 193 1 (IwtnflMt, fb* rty*tef<ww IfrmftrntfiK will t. r*irrv<q*i>tmjcly Vw MM,? the eatimafa'd rrvuJul wjw will !m lrg**f. At pnirwt, 4 : * frm meat Thi* give* tbn maximum amount of foraterite, *7-9 %, which ia not greatly in excen* of the measured amount. That the observed I be taken a* a lower limit to the crystal rise. Howfw, the fact tbit amount, about 75 to 89%, Is aomewhat tea* is not eerprisrng sines e 4 there m no notintble diminution of the breadfiin| within the time- smalt proportion of 3fg0 might wall he retained in the amorphous silica ft tempereturw limit* of the experiment* suggest* that the dt*torioftal contribution to the broadening may be email to that the crystal eia* phase. What seems most important ** that tb* measurement* point much mere strongly towards th* saoood equation than toward* the itrut. may indeed be e* emaR aa lO-* cm. Thi* reault tmpliee that the diffusion The criticism of Ball aod Tayter (1993, p. 474) that ia previous work proemsre that oeeur in the** topotactic reaction* tab* place over quit* lilies wa* tatrodsced 'merely to balance the chemical equatloos* was a* abort datanee* and this * compatible with the relatively lev tempera* valid criticism, hut the peasant Nsoft* e*em sow to provide at Want a tare* at which the reaction* proceed to completion a* compared with the partial justification. . j'ii! ;:'i! Ufher temperatere* reqeired when for*terite b forroad from mixed powjtn of WgO and 6iOr ZKsewmtsu Cbomieat cyactions for formation offorotcritt. From the WgO-8*Ot equilibrium diagram, for*t<rite and enstatit* would ha expected as reaction product* from the reeryttatlixation of dehydroxylated serpen* tine. The equation can be written: * OsnVsUws of fAo tshaysan mdUsiiM pi epottj bf Boll and Tftor {1993} They eooaidered that the dehydroxrlatioa aad feeryvtaOfsstioa of mrpeuttas in air mayproceed ia four stage* aa foftowu: DoAfiroxytotio*: Protons migrate to reactiou touea where water moleouh* are liberated. Mg and 8i iom oonater-migret# keepiag the Kg:8i retie more or lee* unchanged at 3:3, while the oxygen framework ;:!! Hi (SBfgO.SStOg) -a (2MgO.8iO#)4-(MgO.Sr01) serpentine foraterite essUtite anhydride 99-3% 41-7% remain* largely unchanged. This means that after the torn of water 60m regions that become pores, the remaining oxygen* accommodate aQ the Kg aad 8i ions. The anhydride product la a partly disordered materia! giving *0 essentially 'amorphous' X-rey powder diagram. The intimate mixing of the 'oxides* in the serpentine after dehydroxyla- Cotiom noryomitafioM* A partial seperation into Ifg-rieh aad 8i-rich too would be expected to favour the attainment of equilibrium and any regions begin*, which require* Kg aad 8i baa now to move in opposite '"si;! reasdeaf 'water* might aarist the reaction atnee water often proridet a diraotSom. * catalytic effect Tbs non-appearance of crystalline enatatit* until For*writ* erptaffiaafion. An ordering of cations and a ehsnge to higher temperature# (> 1000* C) are reached raiaes donbt* aa to tb* oxygen ion packiog in tbs )!g-rieh regions leads to formation offorstsrtt*. validity of thi* equation, bat it is not conclusive evidence because if Mnototito formation. The 8i-neh region* change to enstatit* hut this enetatite is alow in crystallising an amorphous phase of enatatita com stage occurs lees readily than the others for reeson* that are not at eR position mar be formed. dear. The fact that the amount of foraterite foeml experimentally, 79 to The present experiment* eonflrtn the fleet stage, namely dehydroxy- 00 % t* mech greater than the amount predicted by thi* equation Wtioa and formation of an * X-ray amorphous* phase. The degree of 'IIItt> O o . * i *i lodieatee that the reaction is probably not proceeding directly toward* the ettimate equilibrium. disorder hs thi* pha** must not he orer-exaggerated tine# topotaxul rWatioos between serpentine and forsterita require peretstenee of some o A eecood equation can be written on the ^opposition that all the MgO degree of order. It ha* been shown that aa recryetaflisation proceed*, o KP r *; ;l: (n the serpentine composition goes into foraterite, tearing a reswfoe of amorphous ailie*: fauterit* (but no enatatite) appear* In flne-graiwed form. Increasing in amount with time and temperature until about 75 to 90 % of the product * .i .i (3Kg0.3SiOJ l-SlTMgO.RiOJ+OStSiOj h foraterite, which require* that practically all the MgO of the serpen* st forsterita *% tm# composition goes to form foraterite. Thi* doe* not support the . 97-5% 1*5% eeond and thin! stage* described by B*l! and Taylor, in which Mg-rich V. PRODUCED R v ..iVr . #4>v rr:' adyXV-' toM^rW '.' %n./*'vr " ..r^r . .V'^ ''** : *' '? ---/' - -/*'. . .. .' .*-' rr/v kSMaiM ikajm : > :tii ; liiir .`iifjsr. . !!!i i;i!S MM* 4 !:!5 !i!ifc l4 0. o. Ar> . PATAItf n )8orpantlnt~| jsarpaotina ) gC^Twj.S'AOK. "4JW29.SI,i02,tyH*. 2`W"J'n3oItAwIH. kss I mgSsigp tMf.*A '-.o I rn,l<a 94 (Of, flgMy "1 dborgoria |forlrttt j --------- i 3 |f*r**f*tf TVAttftmmjrAtiawfl nr nnorairTrpa Ito forrWtr. and In lW rmrmpnnding minima, Hnimtp Af amttot',, gbam am tSr following iwnto* nf Innn: ItP, eonlAtkn 44 Mg, 33 81, 144 0,44 H;*tr, eoninitm TJ Kg, 94 81, (44 0. That tb orataB eatioo `onkango'b: 34 Kg+42:44 H,r Kg+1 W 2t 14 H. 0* tkia tar, tit `donor* ragteat okato rtttf tnolrcrlaa a/a formrd doaata (g KgA-18t) to tbo ?aeoaptor` ngiona in acckanga for 14 protow. A kigkly dbordatad ntnatian anan in akitl U `donor' itgioaa ara prokaktp targalf ailjoa and tka 'aocaptor* lagiona kara a eanpeattba approiiaMtugtotkatafetaMta. WKkbaat-treatmmttba'aeeaptor' ragbaa baooaa orgaabad la aoal doaniaa of for^attta, vklek aocotanedata ptaetieaD/ aO tka Kg Iona of tka erigtaa! aarpootino. Tito doauaa ako* fittlo tondaaof to aalarga tkair an aitk tka kaat-tnataota anployad. Tka difloaltf of fomiag mrtatita b aaaa aa arWag kaa tka aatara oftkaraartiiiamaolrad.aaaalyaraaetionkataaaaaatora orlaaaatakla forvtarito aad azeato aiHea. Tka too feacbaabna pupuaad art aat oat aekamatieatfy tm ff. t. akick abort tka qaaab'totira raktma tarolrad aod tka a^rozbaato laapacmtataa at wkiek laaotma ooear. Tka markanbw pnpaaad \f tka fnaart vritata takaa into aeeooat tka kigk proportion af tka VgO oootaat tkat antan bto fontarito and offwa ainpk axpbnation for tka dalajad appaaianra of aaatotrta. [fbmtprltal [goaWItol ' *- `r-L, jewtypWt] Ir* nnrati i itr ltk mniA oat utpaW tf a grant Aaaa tka Katiaaaf > r.aadftton, orm. anrata (O.W.i.). Tka puOHpatka af tyraa Banal ora aada pvlkla kf a akalanUa traa tka gikaia and Ta.kalay Aaaaryaflka/rpaaaiOuiaaaaalanf kpbaraafakann kaa tkrOrrianrat lafnMal kn--rak tiaUtata, Otaka. Jpa. Aatotanra *h prartM aba kp tka tortanl knllpa af tka Oltifi af tUnnl lodaMHaa, Tka harnplraala bata OabanMp, i-li;! Soil - Toyfer - Mojruwf fkf.too, eC'fboa*rpaSrctohaeamfreairtkur .-- pmponl Beeetie* Vy Bril and Scheme T;br trd kp k t ! *<u.)K. C) a) Tanoa (ft. T. W.). IMI. Xta. Ka., rat *t. p, 7tt. -----last rm.. mi. n. p.?. Iuut (0. w.k (Ml. Joam. Uln. tor. fapaa, rat A p. T. piw--t wtiin. ^ -----1ana. Pragr. Oma. to)^ nt tpL a> ----- aad Znattaa (J.), ItST. Aanr. Stta.. ra. 41 p. Ml. 9 in) g-rfch rogiona ara darrlopod giving ri*a aapaetira!/ to forrtarita Tamn (R. T. W.), Itat. dap Min. ton, a. a. p. 4*. o o ad eaeUtite. [ rift rrailMf ft /aaa !9tf.J o Am effewefir*form oftf* Vwf^w^tr1 mceftemem in slls! It &m been *hon pnvtovAf (Brin*tV^# IWt, 1W3) that the topo* ^ !> OD toetie reUt*o*wh*p between eefpentine amt foceterite fettle to the &* . elwion that eight onit eefle of serpentine home nine mt eefb J uau4A udonaonj u - rn. : >V * IWM^ vvv- 5 *: 'J'tat. . fC.'.