895 The Canadtan M inerak> gist Vol. 36, pp. 895-903(1998)

MELILITOLITES:A NEW SCHEME OF CLASSIFICATION

ELIZABETH ANN DUNWORTH' .aTNoKEITH BELL

Ottawa - Carleton Geoscience Cente, Depamnent of Earth Sciences, Carleton University, Onawq Ontario KIS 586

Arsrnecr

A new scheme of classification is proposed for metilite-bearing plutonic rocks with more than l07o melilite and less than 507o pimary carbonate phases,based on the absolute modal abundancesof the dominant . Melilitolite is retained as a "general" root-name for all such rocks. Previous definitions of terms used in the classification of these rocks, including afrikandite' kugdite, okaite, turjaite and uncompahgrite, are modified in order to provide "specific" root-names for melilirolites. A new rock-name, "ultramelilitolite", is proposed as a specific root-nams f6l samples with more than 657o melilite. The use of multiple root-na.mesand the problems associatedwith the use of modifiers in rock nomenclature are discussed.

Keyword:; melilitolite, afrikandite, kugdite, okaite, tudaite, uncompahgrite, "ultramelilitolite", modifier, root-name.

Sonauenn,

Nous pr6sentons ici un nouveau sch6ma de classification visant les roches plutoniques contenant plu s de 70Vode mdlilite et moins de 507o de phasescarbonat6es primaires, et fond6 sur Ia teneur des min6raux dominants en termes absolus. Nous re- tenons le terme "m6lilitolite" comme racine du nom de telles roches. Les d6finitions utilis6es ant6rieurement dans le classification de ces roches, par exemple, afrikandite, kugdite, okarte, tu{ar'te et uncompahgrite, sont ici modifi6es afin d'en arriver d des noms de base spdcifiques dans ce sch6ma.Un nouveau nom, "ultram6lilitolite", est propos6 pour les 6chantillons contenant plus de 65Vode m6lilite. Nous discutons I'utilisation de noms de base multiples et les problbmes associ6str I'utili- sation de noms de mindraux collme qualificatifs dans la nomenclature de ces roches. (Traduit par la R6daction)

Mots-cl6s; m6li1itolite, afrikandite, kugdite, okar'te,turjarte, uncompahgrite, "ultram6lilitolite", qualificatifs, noms de base.

IxrnooucrroN rocks. Included in this scheme was a section on melilite-bearing intrusive rocks, based on a classifica- Althoughmelilite-bearing igneous rocks are compara- tion scheme first proposed by Egorov (1969). This tively rareon a worldwidescale, these unusual rocks play scheme uses (and in some casesredefines) nomenclature an importantrole in assessingthe petrogeneticsignifi- taken from the intemational literatwe. Although the clas- canceof mantlederivd SiOlpoor .The current sification schemeby MikhasTovet aL (1995) is one of the IUGS classificationscheme for melilite-bearingintrusive most realistic attempts to classify melilite-bearing intru- rocks proposedby Streckeisen(1979) nd Le Maitre sive rocks thus far, it has two drawbacks: (i) it strays too (1989),and recently aftumed by Wootleyet al. (7996), far from the original definitions of the terms used in the definesboth innusive and extusive melilite-bearingrocks nomenclature, and (ii) it does not follow current IUGS solelyon thebasis of threeminelal components:melilite, guidelines on rock nomenclature. In a detailed classi olivineand . Unforfimately, ttrese minerals do not fication of undersaturatedalkaline rocks, Mitchell adequatelyreflect the mineral assemblagespresent in (1996) included a section on extrusive and intrusive worldwide,plulonic, melilite-bearingrocks. melilite-bearing rocks which provided a compromise A classificationscheme called the Petrographic between the schemes of Woolley et al. (1996) and Codewas formulated by Mikhailov et aI. (1995)in an Mikhailov et al. (1995), but did not sufficiently reflect attemptto classifyall magmaticand metamorphic natural mineral assemblages.The present paper sum-

I Presentaddress: Mineralogisk-Geologisk Museum, San'gate 1, OsloN-0562, Norway. E- maiJ address: [email protected] 896 THE CANADIAN MINERALOGIST marizes previous work on the description and classifi- Olivine-bearingmelilite rocksfrom the KugdaMassif cation of worldwide intrusive melilite-bearing rocks, within the Maimecha-Kotui Province in Siberia were and provides a new, comprehensivescheme of classifi- termed"kugdite' by Egorov(1969). Most melilite-bearing cation based on their modal mineralogy, which respects rocksfrom the otherMaimecha-Kotui massifs have been both old terminology and modern guidelines regarding classifiedas kugdite,okaite, turjaite anduncompahgrite, the nomenclature of igneous rocks. usingthe scheme of Egorov(1969). The Maimecha-Konri provinceincludes the Guli massif,the largestalkaline complexin theworld (1500km'z), which alsocontains Swnraenv oF PREYIoUsWoRK melilitoliteand kugdite (Yegorov 1989). Kovdorite, also describedas an olivine turjaite, was found in the Early afiempts to name intusive melilite-bearing rocks KovdorMassifbyAatlctnd(1945). Detailed sutdies of the were made in the filsthalf of the twentieth cenurry.l,arsen Kovdorrocks were subsequently carried out by Kupletsky & Hunter (1914)used ttre terrn'tncompahgrite'to define (1948),who devisedan earlythree-component scheme of a melilitelyroxene rock from hon Hill, Colorado. l.arsen classificationfor the samples.Kukharenko et al. (1965) (1942) subsequentlydescribed an averageuncompahgnte describedmelilite-bearing samples from Kovdor,includ- from Hill as containing 68Vo melilite, 15% ing kovdoritesand tudaites,4s goltaining significant clinopyroxen e, | IVo magnetite o 3 Vo perov skite, 2Vo quantitiesof olivine (

The schemeproposed in the presentpaper is based i) follow thecurrent IUGS guidelineson thenaming of on the modalmineralogy of a worldwide spectrumof igneousrocks, ii) clearly defineprevious melilite-bear- intrusivemelilite-bearing samples, as shown nTable2, ing rock nameswith respectto each other, and iii) andprovides a conciseand descriptive terminology for respectthe original definitions of the previousrock their classification.The proposedscheme attempts to: names,as far aspossible.

TABII 2. MoDALMINERAITOGY oF MELILrroLrrEs woRLDwrDE,AND NEw cLAssIFIcATToN

Massif Litsafirrename AryAp CalcmftHynt tMgtMel Mi MlcNe Ol pruCpx l/ Pre'fix Specffic root-nane

Rangwalu unjaite l0 | 4045 I 3 tr 99 apatite-mic€ molilitolite turjaite E5313 3 ts5 97 afrikarulhe aujaite 4 1559 5 2 t3 2 98 nagnetite afrikandite uncompahgrite r634 2617100 uncompahgrite uncompahgirc t659tr r15 l 100 megnetite afrikandits hon tfll [2] uncoryahgrite Itr l0 5G. 2 <5 3 15

Oka [3] okaite <5 <5 <40 <5 30- <5 <40 <5<10 nepheline okaite 90 hatyne Atrjaite nephelineokaite < ,10 <5 4040 bailpe turjaite hailyn*pyroxeneokaite <5 <5 40 30< 10 60 okaite -l4l PJrcXene okaiter 2- t5- 5- 30- 1- t- 100 calcite melilitolite 550 1070 s 5 nephelinemelilitolite tr3 5305 50550 turjaite 50 nephelineokaite l3 5 3Gt0 3G I 5G. turjaits 50 50 70 - tsl okaite 2 66516 4 t00 mtca 'ultramelilitolite" okaite 27 569E 6 100 "ultramelilitolits'

Piandi Celle[6] calcite-leucite 2542t 90.57l.s 5 68 calcite-lorcite melilitolite melilitolits

TuIV t4 calcitemelilitolitei 2E 1055 2 I 2 tr 100 calcite melilitolite trjaite r 5 Nt2 35 5 6s ufjsite tu!'aite t2 3 46n n 3 77 mica hdaite turjaite 4l 3020t2 2t 5 72 magnetite turjaite - ttl rtrjaite 44164 3 3035 tr 4 84 cancrinite-nica melilitolite melilitolite trl 2 7656r10 5tr90 nepheline "tltranelilitolite'

Kovdor [9] turjaite <5 <5 <525-2U 15- <5 5- 70- p)rcxene unmmpahgrite 50 25 30 25 85 nepheline turjaite - tlOl melilitolite 1904

Afrikanda[Il] aftikandite 5 10 75 l0 100 perovskite hgdite 898 TIIE CANADIAN MINERALOGIST

TABLE 2 (cont'd). MODAL MINERALOGY OF MELILITOLITES WORLD\fIDE, AND NEW CLASSIFICATION

Massif Iiteraturename AnpAp CalcocrtHynkiMgtMelMiMENo Ol Pncpx M' Preft( Specific root-name

It{ainecba- Kotui province[12] Odehincha unmmpahgrite 6E 30 100 tultrameliliolite' PJtroxene 'ultramelilitolite' Kugda uncompahgdte t376 | 0.3l0 100 pyrcm€ Kugda olivineunonrpahgrite 9 74 0.5 l0 7 100 olivine fulrramelilitolite" Kugda nephelineuncompahgrite t6s9 4 3 t34999 nagnetite melilitolite Bihit-Zspad ne,phelineuncompahgrtre 974 45 7 96 fultramelilitolite' Bitrit-Zapad torjaite l0 64 0.3 102 15 90 nephelino uncompahgrite 'ultamelilitolite" Kars-Mery turjaite 3774 91 7 91 t0 62 t4 9 s91 melilitolite Nemaket turjaite -dtramelilitolite" Odehincha turjaite s66 l0 3590 nepheline Atrdyak tudaite l5 32 0.5 201 25t0 nephelinrmagnetite uncompahgrite Changit porpffiic nrjaite ts25 6 155 3sEs nepheline-magnetite uncompBhgrite Biffi-Za,ptd olivineurjaite 1258 I 147 | 6 E6 turjaite Kara-Meny olivineufjaite t- 30- 5- 25- 5- 10- 65- pyroxene turjaite l0 35 10 35 10 t5 75 Romaneecha olivineurjaite 1237 3 14 108 1690 olivine-monicellite unmmpahgrite N€rnakeet olivinearjaite 5 21 "tO 20 10 34 E0 olivine-nepholine uncompahgrite Kara-Ndery olivineurjaite 5 31 5 2a 20 l2 72 pyroxenerlivine tu{ail! clura nephelinenrjaito 83s2 5 30 20 70 pyroxene trr.jaite Odehincha pyroxeneokaite 3565 25 775 trjaite Kara-Mfly okahe 1051 I 38r 62 tudaite Bihit-Vostchy olivineokaite 0.30.3 84t6 333 I | 67 brjaite Kara-Meny okaite 530 50t0 5 50 olhins turjaite N€makeet okahe l 37 ll 29t71 gamel hdaite 'ultranelilitolite' Kugda tugdito 12 70 0.50.5 140.5 2 100 olivine Kugds hedite t2 41 13 134 I h€dite Kugda nephslinekugdite 94813 720 3 93 hrgrlite Culinsky pyroxenehrgdite 430 15 30111@ montiellite kugdite 'tltramelilitolite" culirsky melilitolite 1377 5 2 3100 'ultamelilitolite" Gulinsky olivinemelilitolirc t775 1 7 0.2 tN magnetite Kugda nephelinemelilitolite 256t 2 5 24 95 magnetite melilitolire KWda nephelinemelilitolite 25 72 0.40.6 r I 0.2 t00 magnetite fulranelilitolite-' 'ultramelililolitd' Gedin€rIl3l l2 12 83 11100 2l 10M 2 100 'ultramelilitolite" l0 E3 5 2100 'ultramelilitolite" 'tltramelilitolite" 2- + 0.5- 6 75-0.5 2- 2- t00 35 I 883 I 54 1.5 7.57a t.5 6.5 5 100 fultramelilitolite" l3 18 54 5.5 6 3.5 100 apatite-msgnetite melilitolite 20 2145 9 4.5 100 aparitemagnetite melilitolite 2to t2 63 0.5 12 1.5 100 apatite afrikandite

i alsomelilite cartonarites with >50/o calcite. References:[ 1l I: Bas(1977), [2] I.ars€n(1%2), [3] cold ?t al (1986),[4] Tre"nm & Essene(1985), [5] Eby(1973), [6] Stoppae, 4l (1997),a\ Drmrorth (tr[ tt] Be[ et al. (1996),[9] Arzmastsw (1994),[l0] N.S. Rudachwslry,unpubl. data, fl 11E.A Dmwort\ unpubl.datq [2] Egorov (l%9) [t3] T. Niels€rl(pers. com'n., lD7). The symbolsused are those of Kretz (1983),qc€pt thd Mgt is chos€nfor nagnethe. In addition,Amp reFesens gmFhtole, andM repres€ftsmica.

Root names plutonic rocks containing >10% modal melilite and4o%o modal primary carbonate@oolTey et a\.1996), as shown 1. Melilitolite is affirmed as a general root-name for all in Figure 1. Any samplecontaining <10% melilite is not MELILITOLITES: A NEW SCHEME OF CLASSIFICATION 899 a melilitolite andshould be definedon thebasis of the Modifiers rest of its modalmineralogy with "melilite-bearing-" usedas a prefix (Le Maitre 1989).Samples of this na- Modifiers are normally used to denote high quanti- ture fall into the shadedarea in Fisure 1. ties of a particular mineral in a sample. We suggested that any mineral with more than IUVoabsolute modal abundance in a melilitolite should have the mineral name added as a modifier to the root name; where more than one modffier is requfued, the modifiers are listed in pnmary order of increasing mineral abundance. However, the carbonate "defining mineral" used to define a specific root-name, as describedabove, should not be used as an additional modifier. For example, the schemeprecludes the use of "nepheline turjaite". It is also suggestedthat mica and magnetite should be used as modifiers only where they reach more than l57o absolute modal abundance,given that these min- carbonatite erals are relatively abundant in many samples of melilitolite, as seen in Table 2.

Note ''. melilitolite It should be emphasized that the terms of rock no- menclature derived by using general and specific root-names are equivalent. For example, "nepheline pyroxene melilitolite" is equivalent to "nepheline melilite 100-carbonate-melilite] uncompahgrite". Examples of names derived using the [ proposals above are listed in Table 2.

Rocx NowNclnrune Frc. 1. Classificafion of rocks gontaining primary carbonate, melilite and other minerals, based on modal mineralogy. Rationale The division between melilitolite and carbonatite occurs ar 5OVocubonate, following the flow-chart classification for The choice of minerals used to define the specific all igneous rocks, outlined in Woolley et aI. (1996).T\e 'tltramelilitolite" root-names listed in Table 1 was made on the followinq creation of the specific root-name grounds: within the melilitolite field occurs at 657o melililire. The a) In order to limit the number of root-names in the shaded area represents rocks with less that llVo rnelilite, classification scheme, we have redefined melilitolite which are not considered to be melilitolites. rock-names that already exist in the lilerature wherever possible. kevious names such as afrikandite, kugdite, okaite, turjaite and uncompahgrite have now been de- 2. If more detailed nomenclature is required, and in order fined on the basis of modal mineralogy. to define terms used in previous studies with respectto b) Melilitolites can be broadly divided into tbree main each other, the following use of specific root-names is groups, on the basis of dominanceof silicate, oxide and also suggested.Samples that contain greaterthan ll%o carbonate minerals, as shown in Table 1, and ttre no- modnl abundanceofany ofthe five "defining minerals" menclature chosen reflects these nafural divisions, olivine, pyroxene, perovskite, nepheline and haiiyne, while taking modal mineralogy and the worldwide may use the specific root-name associatedwith that min- abundanceof each group into account. eral, as listed in Table 1. Any sample that contains in c) The definitions of the terms kugdite and uncompahgrite excess of IIVo of more than one of the "defining miner- in this scheme are very similar to those used by both Le als" may derive a specific root-name from the most Maitre (1989) and Mikhailov et al. (1995). However, the abundant "defining mineral", and any less abundant "de- terms turjaite, okaite and afrikandite were listed as "not fining mineral(s)" may be used as a modifier(s), as recommendedusage" by Le Maitre (1989), whereas shown in Figure 2. turjaite and okaite were redefined by Mikhulov et al. 3. We propose that any plutonic sample with melilite in (1995) in the Petrographic Code, as described below, excess of657o should be given the specific root-name but afrikandite was not included. "ultramelilitolite". This aspect of the classification The original definition ofokaite (Stansfield 1923) scheme is explained in further detail in a later section listed haiiyne as an essential mineral, instead of, or as and is shown in Figures 1,and2. well as, nepheline.We have chosento respectthis defi- 900 TIIE CANADIAN MINERALOGIST nition in the new classificationscheme, while recogniz- one of the essentialminerals. In the system nepheline- ing that it has previouslybeen used to describe calcite - H2O, Watkinson & Wyllie (1971) showed that "melilite-nephelineo'assemblages in the classification a reaction of nepheline and calcite produced cancrinite schemesof Egorov(1969) and Mikhailov et al. (1995). under hydrous conditions, and it has been poshrlatedby Similarly, turjaite was originally definedby Ramsay Bell et al. (1996) that cancrinite also can fonn as a pri- (1921)as a rock containingmelilite + nepheline+ mary product of the crystallizatron of a Ca-rich silicate phlogopite.The classificationscheme proposed in this such as tudaite, instead of nepheline. paperhas used the presenceof nephelineto definethe The use of the term afrikandite to define the melilite- useof the term turjaite,while acknowledgingthat the oxide assemblage@) in Table I follows the definition of o'melililite presenceof phlogopitealso is importantin theserocks. afrikandite by Sorensen (1,974) as a - The definitionsof Egorov(1969) and Mikhulov et al. perovskite - magnetite" rock. The type-localiry (1995)Iist nepheline+ pyroxeneas essential compo- "afrikandite" from the Afrikanda massif is, in fact, a nentsin turjaite, but given the limited occurrenceof melilite-bearing olivinite containing -lUVo meliltte, l5Vo pyroxenein the type-localiryturjaites of theTuriy Mas- perovskite + magnetite, and 75Vo olivine. The term sif, this definition has been rejected.The original "afrikandite" is no longer used in the Russian literature definitionof turjaite@amsey 1921) listed nepheline as given the definition ofSprensen (1974), along with the

Start here < 10Yo modifi er only: melilite-bearing (forfurther classification return to the IUGSflow chart of Woollqt et al. (1996))

> 1004

< 650 melilite most abundant defininemineral > 10%

perovskite afrikandite olivine -} kugdite

hauyne ------t okaite nepheline -) tudaite pyloxene uncompahgrite

none ofthese

i does any mineral, other than melilite and any mineral used .-_--**-_l

_...... ______._,,______-J

* It is suggested that> 1594beused root-nameonly for magnetite list theseminerals in order of and mica. increasingabundance in front (generalor specific) ef 16sf name(ge,neral or specific)

Flc. 2. Flow-chart classification for plutonic rocks that contain melilite. It should be noted that the use of specific root-names is optional, and that terms of nomenclature derived using general and specific root-narnes for any given sample are equivalent. MELILITOLITES: A NEW SCHEME OF CLASSIFICATION 901

fact that the rype-localifymaterial contains significant The useof M' in the classificationof melilitolites,as quantitiesof perovskite+ magnetile,we havechosen to suggestedby Woolley et al. (1996) and Le Maitre retain this term to describemelilite--oxide assemblages. (1989),should be discontinued,as M' shouldonly be usedto classiff samplesthat fall within theQAPF dia- "ULtnalreuLnolrreo' gram.This also impliesthat paragraphB.8.2 of Le Maitre(1989), where it is suggestedthat rocks contain- A term to specificallydescribe melilite-rich intru- ing more than l0Vomelilite and with M' lessthan 90 sive rocks,based on theabsolute abundance of melilite, shouldbe named"melilite nepheliniteo'(or, presum- has been lacking up until now. In the olivine - ably,"melilite ijolite"), is incorrect. clinopyroxene- orthopyroxenescheme of classifica- Thirdly, the suggesteduse ofthe terms"general root- tion of ultramafic rocks (Le Maitre 1989),the term name"and "specific root-name" throughout this paper pyroxeniteis usedto describerocks whose mafic min- hasimplications for the classificationof otherigneous eralogy is dominatedby pyroxene.Similarly, in the rocks,where similar situationsfrequently arise. For ex- previousolivine - pyroxene- melilite schemeof clas- ample,in the classificationof ultramaficrocks, the term sification of intrusive melilite-bearingrocks (Le Maitre peridotitewould becomea generalroot-name, whereas 1989),the term melilitolite wasused both as a term to lherzolite,wehrlite and harzburgitewould becomespe- describerocks with [melilite/(melilite + olivine - cific root-names.Similarly, in theclassification of more pyroxene)l>90Vo and asa generalroot-name to de- SiO2-richrocks, trachyandesite (general root-narne) can scribeany intrusiverock with melilite> 107o.Such be divided into benmoreiteand latite (specific root- dual usageis inadvisableand misleading for purposes names),and there are many other examples.It is of rock nomenclatureand classification. In our new important to note that the namesderived from general proposed scheme, we prefer to use the term or specificroot-nurmes should be consideredequivalent "melilitolite" asa generalroot-name to describeintrusive in rank,and that specific root-names are not "sub-root- sampleswith greaterthan ll%o melitte (andless than names". 50Vopimary carbonate).For thosemelilitolites that con- We believe that the melilitolite classification tain a high modal abundanceof melilite, a new specific scheme6utlined above is to be preferredto the previous root-nameis required.Thus, the term "uhamelilitolite" IUGS classificationscheme for melilitolites (t e Maitre is suggestedhere as a specificroot-name for plutonic 1989,Woolley et al. 1996)on the following grounds: rockswith melilitein excessof 65Vomodal abundance. i) The mineral assemblagespresent in worldwide 'hltramelilitolite" Examplesof arelisted in Table2. melilitolites are inadequatelydescribed using the olivine - pyroxene- melilite triangular plot of Le (1989), DrscussloN Maitre giventhe wide variationin themodal mineralogyof naturalmelilitolites, as outlinedin Ta- bles I and2; The new scheme of classification proposed in this ii) All namesin the proposedscheme are based on the paper has been evaluated using the worldwide modal absoluteabundance of all mineralspresent, which we abundancedata listed in Table 2. From the information beteve to be moreinformative than ratioed proporrions provided in this table, it can be seen that a variety of neededin orderto usetriangular plots. [n a classifica- melilitolites are representedwithin individual massifso tion schemewhere only lOVoof a single mineral and that the new terminology provides concise and (melilite)is essential,nomenclature is requiredthat re- clear descriptions for almost all 1[s samples. flectsthe restof the 6661a1minerals; There are a number of points to note regarding the iii) There is an inconsistencyin the use of modifiers relationship between the classification scheme pro- with the methodsproposed by Le Maitre (1989).The posed here, and the current IUGS classification of purposeof modifiersis to emphasizethe presenceof igneous rocks. Firstly, Figure l, based on an early part high modalabundances of certainminerals. Modifiers of the IUGS flow chart for the classification of igneous suchas those used by t e Maitre (1989)in their olivine rocks outlined in Woolley et aI. (1996), provides a - pyroxene- melilite triangularplot (e.g.,"olivine- diagrammatical representationof the sequential classifi ca- pyroxenemelilitolite") aresolely defined on the basis tion of carbonatites and melilitolites. Some melilitoliles of thetrrehrtve abundancewith respectto the othertwo can contain sigrrificant quantities of primary or secondary minerals,and not in relation to their absoluteabun- carbonatephases, but the presenceofprimary carbonateis dancein the sample.The subsequentuse of additional the sole criterion for defining the top apex ofFigure 1. modifiers,based on theabsolute abundance of a mineral Secondary carbonatephases may be detected using peffo- within a sample(e.9., >lOVo), introduces complications graphic techniques, cathodoluminesence spectroscopy or when simultaneouslyusing modifiers defined using geochemical relationships. different criteria. The classificationproposed here uses Secondly, another aspectof the earlier IUGS classi- six definitive minerals (melilite, olivineo pJnoxene, fication of melilitolites (Le Maitre 1989) that has not perovskile,hatiyne and nepheline)to classify specific yet been discussedis the use of the mafic index M'. root-names(table 1), and all modifying prefixesused in 902 front ofthe general or specific root-names refer only to REFERENCES absolute modal abundance. The classification schemefor intrusive melilitolites ARzAMAsrsEv,A.A. (L994): Unique Paleo4oic Intrwtow of proposed in this paper no longer corresponds to the the KoIa Peninsula. Russian Academy of Sciences, mineral assemblage used to classify their extrusive Apatiry, Russia. equivalents,as proposedby k Maitre (1989). The min- Bprr, K., Durrwonru, E.A., BL'r-AKH,A.G. & Ivatrrrov, V.V. eral assemblage melilite - olivine - pyroxene - (1996): Alkaline rocks ofthe Tirriy Peninsula, Russia, in- nepheline is common in melilite-bearing extrusive ig- cluding type-locality turjaite and turjite: areview. Can. - neous rocks; therefore, we contend that the olivine Mineral. 34,265-280. pyroxene - melilite (melilitite) triangle of Le Maitre (1989) is suitable for classification of extrusive rocks CmvNSKn, P.N., AFANASEV,M.S. & Ussarove, E.G. (1940): with more than lOVo melilite. The dissimilarities in The massif of ultrabasic rocks at the Afrikanda railway modal mineralogy between extrusive and intrusive station. Trudy Kolsl

Mrcnnov, N.P.,Econov, L.S., Menw, Yu.B., MARKovsKy, STREcKEISEN,A. (1979)t Classification and nomeclatureof B.A., MAssAms,V.L., Mosxar-rva,V.N., Rumarrsnve, volcanic rocks, ,carbonatites, and melilitic N.A. SranreNox"L.N. & Sm,cLsvA,K.L.(1995): Petro- rocks: recommendationsand suggestionsof the IUGS graphic Code: Magmatic and Metamorphic Rocks. Subcommissionon the Systematicsof IgneousRocks. VSEGEIPress, St. Petersburg,Russia. Geology7, 331-335.

MITCHEI,R.H. (1996):Classification of undersaturatedand Tuwe, A.K. & Gnocm, R.M. (1965):Carbonatite and re- relatedalkaline rocks. In UndersaturatedAlkaline Rocks: latedalkalic rocks at Powderhorn.Colorado. Econ. Geol, Mineralogy,Petrogenesis and Economic Potential. Min- 60,672-692. eral. Assoc.Can., Shon CourseVoI. ?A. l-22. TREMAN,A.H. & Esswe, E.J. (1985):The Oka carbonatite complex, geologyand evidence for silicate- car- Nasn,W.P. (1972): Mineralogy and petrology of thehon Hill Quebec: bonateliquid immiscibility. Am, Mineral.70, 1101-1113. carbonatitecomplex, Colorado. Geol. Soc.Arn., BulI.83, l36t-1382. WerrwsoN, D.H. & Wvu-m, P.J.(1971): Experimental study of the compositionjoin NaAlSiOo- CaCO,- tPO and the Nrenrrv, T.F.D. (1980): The petrology of a melilitolite, genesisof alkalicrock - carbonatitecomplexes. J. Perrol. melteigite,carbonatile and syenitering dike systemin the t2,357-378. Gardinercomplex, East Greenland. Litho s 13, 18 I - I 97. WooIIFy, A.R.,Bnncuar, S.C., Epcan, A.D., Lr Bes,M.J., RAMsAy,W. (1921):En melilitforandedjupbergarr fran Turiy MrrcHELL,R.H., Rocr, N.M.S. & Scor Svrmr, B.H. pa sydsidanav Kolahalvon.Geol. Fdrett StocWtolmFdrh, (1996): Classificationof lamprophyres,, 43. kimfuqlite5,and the kalsilitic, melilitic a-ndleucitic rocks. Can.Mineral. 34, l7 5-L86. SpnENsw,H. (1974):Glossary of alkalineand related rocks. 1, 1Xsfilkaline Rocks(H. S6rensen,ed.). J. Wiley & Sons, Yrconov, L.S. (1989):Form, structureand development of New York,N.Y. (558-577). the Guli ultramafic-alkalicand carbonatitepluton. Izr. Geol.Rev.3l,1226-1239 (author's name also spelled Starsrrnro, J. (1923): Extensions of the Monteregian Egorovhere). peEographicalprovince to the westand northwest. GeoL Mas.60,433-453. Zr-crKrvD,T.G. (1945):Olivine turjaitesftovdorites) - new plutonicmelilitic rocksin theKola Peninsria).Sov. Geol. Srorna,F., SnanycN,V.V. & CLNDAnr,A. (1997):New min- 1945(7),88-95 (in Russ.). eral datafrom the kamafugite- carbonatiteassociation: themelilitolite from Piande Celle,ltaly.Mineral. Petrol. ReceivedApil 25, 1997,revised maruncript accepted December il.n45. 15.1997.