Solid Solution Ino and Classification Of' Gossan-Deriyed Members Of

Home , Gossan, Hidalgoite, Jarosite, Plumbogummite

American Mineralogist, Volume 72, pages 178-187, 1987

Solid solution ino and classificationof' gossan-deriYed membersof the alunite-jarositefamily, northwest Queensland,Australia Knrrn M. Scorr CSIRO Division of Mineral Physicsand Mineralogy, P.O. Box 136, North Ryde, NSW 2113, Australia

Ansrnlcr Minerals of the alunite-jarosite family with the generalformula AB3(XO4)r(OH). occur in gossansrelated to Pb-Zn mineralization in the Mount Isa region of northwest Queens- land. Examination of 226 electron-microprobeanalyses indicates that extensive solid so- Iution occurswithin the A, B and (XOo) sites,with the variations in the A and (XOo) sites often related. Substitution of divalent cations for monovalent cations in the A sites of alunite or jarosite can be balanced by (l) replacing two monovalent cations by one divalent cation and leaving A-site vacancies,as in plumbojarosite, (2) incorporating divalent ions in the B sites, as in osarizawaite and beaverite, or (3) replacing divalent anions with trivalent anions, as in beudantite. A secondtrivalent anion can still maintain chargebalance pro- vided it is protonated, as in plumbogummite. Complex interaction of the mechanisms often occurs. Complete solid solution betweenAl and Fe in B sites occurs at least in the more phosphate-rich alunite-jarosites.Nevertheless, because ofthe probable stability differencesand easeof practical subdivision, separation into alunite and jarosite supergroupsaccording to greaterAl or Fe occupancyis consideredappropriate. A classification that prevents proliferation of named minerals of the alunite-jarosite family has been approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association.

fNrnoructtou Minerals of the alunite-jarosite family have the general betweenA and (XOo) occupancy.Substitution of one tri- formula AB.(XOo)r(OH)u,where A is a large cation, such valent for one divalent anion as in the beudantite group as Na*, K*, Ag*, NH4+,H3O*, Ca2+,Pb2+, Ba2+, Sr2+, is accompaniedby a concurrent changein the A-site cat- Ce3+,and other rare earth elements in l2-fold coordi- ion from monovalent to divalent. Complete replacement nation. B sites are occupiedby the cations Al3*, Fe3*, by a trivalent anion is accompaniedby substitution of a Cu2*, and Zn2+ it octahedral coordination. The anion trivalent cation on the A site as in the caseofflorencite, (Xoo)" may be SO? , PO?-, AsOl-, Co3-, SbOi , CeAlr(POo)r(OH)u.Alternatively, if the A-site cation re- CrO?-, or SiO? . Al or Fe is the major occupant of the B mains divalent, protonation of one of the trivalent anions sites, but with the plethora of possible combinations in also results in a stable compound, as in the caseof gor- the A and (XOo) sites,the minerals are usually considered ceixite, BaAl,H(POo),(OH)u(Radoslovich, 1982). In this in three groups based on the nature of the anions (e.g., paper it is argued that these alternatives are sufficiently Palacheet al., 1951;Strunz, 1978;Ramdohr and Strunz, different to warrant separateclassification as "florencite" 1978):(l) alunite group,with two divalent (XOo)anions and "plumbogummite" groups. and usually monovalent A cations; (2) beudantite or Although solid solution has been frequently reported woodhouseitegroup, with one divalent and one trivalent in the A sites,similar substitution within the B and (XOo) (XOo) anion and usually divalent A cations; (3) plum- sites of minerals is poorly documented. This paper pre- bogummite, crandallite, or goyazitegroup, with two tri- sents compositional data for 67 minerals of the alunite- valent (XOo) anions and either divalent or trivalent A jarosite family found in 46 gossan samples derived by cations. oxidation of mid-Proterozoic Pb-Zn mineralization in As seenabove, different nameshave been proposedfor northwest Queensland, Australia. It shows that phos- the same groups. In this paper the nomenclature of Pa- phate-sulfatesolid solution from POo/SOo: 0 to at least lache et al. (1951) has been followed, with some slight I is related to the occupancyofthe A sites.Extensive Fe- modification. Al substitution, especiallyin volcanogenicdeposits to the The subdivisions above reflect the strong relationship east of Mount Isa, is also reported. 0003-o04x/87l0102-0 1 78$02.00 178 SCOTT: ALUNITE-JAROSITE FAMILY r79

SunsrrrurroN AND cLASSrFrcATroN-A REVIEw Table 1. lonic radiifor A- and B-sitecations and bond lengths for (XOo)anions (in A) In addition to monovalent ions, divalent Ca2+and Pb2+ B sites A sites XO4sites* may substitute in the A sites. Two different modes of substitution are known: some A sitesare left unoccupied Al3* 0.51 Na* 097 H"Ot 1.24 c-o 1.22 Fe3* 0.64 Ca2* noo Ag- 1.26 s-o 1.43 to maintain the total A-site charge at one, as in mina- Ti4- 0.68 La3* 1.02 K+ 1.33 -t-u 1.50 miite, (Nao.uKo,oCaorr)Al3(SO4)r(OH)6(Ossaka et al., Cu" 0.72 Ce3* 1.03 Ba'?* 1.34 P-O 1.56 As-O 1.78 I 982), or plumbojarosite,Pbo,Fer(SO4)r(OH)6 (Szyman- Zn2* 0.74 Sr'?* 1.12 NHf 143 Pbr* 1.20 ski, 1985),in which 270/oar'd 500/0,respectively, of the A (1976). sites are unoccupied. Alternatively, Note; Data from Weast (1968, p. F152-F1 57) and Botinelly in beaverite, - Average X-O bond lengths. Pb(Fe,Cu)r(SOo)r(OH)6,and its Al analogue, osarizawaite, Pb(Al,Cu)r(SOo)r(OH)u,the chargebalance is maintained by a combination of partial substitution of (CrOo)oo(SOo)o,o(OH),,, (Walenta eI al., 1982),where in- the divalent ions, Cu and Zn, for trivalent ions in the B tersubstitutions occur in A (and B) sites as well. Never- sites and by some deficiencyin the occupancyofthese B theless,except for minor variation about the named stoi- sites(Jambor and Dutrizac, 1983). chiometric endmembers,large-scale substitution in (XOo) Within the plumbogummite group, where A is gener- sites is not well documented. ally divalent, the chargebalance was originally assumed Substantialsolid solution betweenAl and Fe in B sites to be restoredby protonationofone ofthe OH radicals, is also poorly documented, although intermediate com- giving plumbogummitethe formula PbAl3eO4)r(OH)s. positions betweenalunite, KAl3(SOo)r(OH)u,and jarosite, HrO. However, structural work (Blount, 1974; Radoslov- KFe.(SOo)r(OH)u,do exist (Brophy er al., 1962). Similarly ich, 1982) indicates that the extra proton is actually at- a seriesbetween osarizawaite, Pb(Al,Cu)r(SOo)r(OH)u, and tached to one of the XOo anions so that the generalized beaverite,Pb(Fe,Cu)r(SO1)r(OH)6, is known (Paaret al., formula is better written AB.(XO4XXO.OH)(OH). or 1980),but in this casethere is the addedcomplication of AB3H(XO4)r(OH)6.With one divalent and one trivalent divalent ion incorporation in B sites. Alunite may form anion, such minerals could be consideredas members of, under higher pH conditions than jarosite (Hladky and or a subgroupwithin, the beudantitegroup. However, the Slansky, 1981). Stability differencesbetween otherwise protonation of a trivalent anion modifies the P-O bond similar Al- and Fe-rich members also occur generally lengths to make its space group Cm rather than R3z (Hladky,pers. comm., 1982).Furthermore, because ofthe (Radoslovich, 1982), thereby justifying retention of the size difference between Al3* and Fe3+ (Table 1), B-site classification"plumbogummite group." Members with a occupancy influences ao and is readily differentiated by trivalent A-site cation and two "true" trivalent anions X-ray diffractometry and optical methods. Therefore Bo- need to be distinguished from the "plumbogummite tinelly's (1976)suggestion ofinitial subdivisioninto sep- group" as defined above. Therefore they are designated arate Al- and Fe-rich serieshas much in its favor despite members of the "florencite group." the degreeof intersubstitution illustrated below. Solid solution in the A sitesis well documentedwithin In such a scheme,initial subdivision would be into the groups, e.9., among jarosite, natrojarosite,and hydro- "alunite supergroup" or'Jarosite supergroup" depending nium jarosite (K,Na,H.O)Fer(SOo)r(OH)u(Brophy and on the dominant B-site cation. Logically, the valency of Sheridan, 1965). However, substitution involving differ- the (XOo) anions would then be usedto further subdivide ent valencies in the A sites has also been documented the seriesinto groups as in Table 2. Three factors could between the endmembers florencite, CeAl,(POo)r(OH)u, be usedto argueagainst the proposedclassification, name- crandallite, CaAl.H(PO.)r(OH)u, gorceixite, Ba- ly, possibleconfusion in nomenclature(i.e., "alunite" and 'Jarosite" Al3H(PO4)r(OH)u,and Eayazire,SrAlrH(PO.)r(OH)u refer both to a supergroupand a specificgroup (McKie, 1962).Here substitutionof divalent Ca, Ba, or within that supergroup),the comparative rarity of mem- Sr for trivalent Ce could be balanced by either substitu- bers of the lusungitegroup, and the absenceof known Fe tion of SOo2for POi- or protonation of phosphate.Al- equivalentsofthe florencitegroup. However, thesefactors though McKie (1962) found some minor sulfate substi- are outweighedby the practical considerationsofthe ease tution, protonation of the phosphate appears to be the of the initial subdivision into Al- and Fe-rich seriesand major factor in balancing the charge. However, in the the differencesin formation conditions. system alunite [(Na,K)Alr(SO.),(OH)6]-woodhouseite Geor,ocrc sETTTNG [CaAl,(PO. )(SO*)(OH)u ]-goyazite [SrAl.H(pOo),(OH)u ] (Wise, 1975), variable A-site valencies are balanced by Minerals of the alunite-jarosite family occur in gossans SO.-PO4 intersubstitution. Similar large-scaleintersub- at Mount Isa (in the Bernborough,BSD, DDH 2625, and stitution ofdivalent and trivalent anions has recentlybeen Black Star areas), Copalot, Mount Novit, Hilton, Lake reported in the casesof schlossmacherite,(HrOo urCao rr- Moondarra, Kamarga, Dugald River, Jolimont, Pegmont, NaoouKo ooSro o,Bao o,)(A1, ,oCuo o.Feo or)(SOo), ou- and Fairmile (Fig. l). Except for the last four prospects, (AsOo)o,o(OH),ou(Schmetzer et al., 1980),and philips- the deposits are associatedwith Carpentarian dolomitic bornite, (PboroMno or)(Al r ruZnoonCtto orFeo or)Ho.r.(AsOo), rr- shalein a 40-km north-south belt centeredon Mount Isa 180 SCOTT: ALUNITE-JAROSITE FAMILY

Table2. Classificationof groups in the alunite-jarositefamily

B site Alunitesupergroup Jarositesupergroup A site (X04) site (mol) (Al > Fe) (Fe > Al) (xo.)F < 0 5 Alunitegroup Jarosite group Alunite Jarosite Natroalunite Natrojarosite Schlossmacherite Hydroniumiarosite Minamiite Ammonioiarosite Osarizawaite Argentojarosite Plumboiarosite Beaverite 0.5 < (xo4)3 < 1.5 Hinsdalitegroup Beudantitegroup Hinsdalite Beaudantite Hidalgoite Corkite Weilerite Kemmlitzite Svanbergite Woodhouseite (xo4)3 > 1.5 Plumbogummitegroup Lusungitegroup Plumbogummite Lusungite Goyazite Dussertite Gorceixite Zavite Crandallite Philipsbornite (xo4)3 > 1.5 Florencitegroup Florencite ?Waylandite ?Eyelettersite and at Kamarga 220 km to the northwest. The Dugald minerals of the alunite-jarosite family, muscovite, and River deposit is 90 km northeast of Mount Isa in a gen- kaolinite. Pb- and Zn-beaing manganeseoxides occur at erally higher-grademetamorphic terranewith slatesrather Mount Isa and Dugald River. Cerussite, anglesite,and than shales,but it shows similarities to the precedingde- malachite-rosasite,although occasionally found in oul- posits(Taylor and Scott, 1982, 1983).The mineralogyof crop, generallyoccur deeperin the gossanprofile (Taylor gossansand ironstones from these shale- or slate-hosted and Scott.1982). deposits is almost invariably goethite, hematite, quarlz, Jolimont is a Zn prospect,160 km southeastof Mount

Table3. Compositionsand namesof selectedminerals of the alunite-iarositefamily, northwest Queensland

No of analy- Location Sample ses Composition.

Pegmont 50619 2 Pboei(Alr 4Feo 'Zno o,XPO4)1e3(SOoL olOHL. Plumbogummite Pegmont 50619 1 Pbo e1(Al2ol Feo 56zno 01XPO4)1 5?(SO4)o 4(OH)4 osolo11 Ferrianplumbogummite Pegmont 50619 1 Pbo e1(Fe1o5Alo eoxPOl)1 s6(SO4)o o4(OH)413 Aluminianlusungite Pegmont 50628A 8 Pbos7(Al1 esFeo soxPOo)1 $(SOo)o 6r(0H)u s5 Ferrian hinsdalite Pegmont 50628A Pb11o(Fe,,1Alo 8eXPO1)l jr(SO4)o ss(OH)6 oo Aluminiancorkite Fairmile 58594 5 Pbo ercao 01(Fe248Alo 3rXPO4), rs(SO1)o r"(OH)0," Corkite Fairmile 58612 2 Pboe2Ko 04(Fe2 66Alo ro)(SOo), rr(POo)o r,(OH)u., Corkite Jolimont 50636 4I Sro *Cao 27BaolsCeo ,oKooulao or(Al. 01XPO1)121(SOo)o Calciangoyazite "rzno ".(OH)" "' DugaldRiver 50568 4 Ko56Pbo r5(Fe2dzno,eCuo oj(SOo). oo(OH)sj6clo oo Plumbianiarosite DugaldRiver 50569 3.. PbosTKo r4(Al2 4sFeo uuXSO4), ,r(POo)o 6(AsO4)o jr(OH)61, Ferrian hinsdalite Kamarga 63541 5t Pboozoao,"Baoor(Al26BZno rrouo ioXSOo),or(POn)ore(OH)5 ssclo,o Calcianhinsdalite Bernborough 58241 7-' Pbo 64Koos(Al2ssznor"FeoorCuo or)(SOo), or(POn)6 o"(AsOo)o*(OH)..u Hinsdalite Bernborough 58244 3t Pbo4sKo36cao or(Al"roZno,uCuo*XSOo), 67(POo)o rr(Asoo)oou(OH)ut" Plumbianalunite BSD 58230 6." KoorPbo,rCaonu(Al" uoFeo,rCuoorZno 6XSOo), ro(PO4)o r6(OH)5 5n Plumbianalunite Copalot 66169A 3"' Pboe4lq@(Al, lsznoo.Feoo,Cuo/(SO4)1 @(PO.)or2(OH)s ssOlo€ Hinsdalite Black Star 58349 3t Ko71Pbo seCao @(Al. roZno urCuo,o)(SO4)r er(PO4)o oo(OH)s 67clo @ Zincianalunite DDH2625 59439 1t Kor"Sror"PboorCao04Bao @(A12 ssCuo,oZno6XSO4), 6e(PO4)oo'(OH)u sClo oe Strontianalunite DDH2625 59465 4.. KosrPbo oocao e(Al2 ssFeo01XSO4)l 7e(POn)o eClo 03 Plumbianalunite ",(OH). Hilton 50377 4.. PboElKossBao 01(Al2 65Feo 27Zno osCuo@XSOn), s,(POo)o4r(OH)5ss Plumbianalunite Hilton 50382 6-. lG 67Pbo1o(Alr 6rFeo".Cuo*Znoor)(SO4), s7(POo)o,3(OH)5 6zOlo 03 Plumbianalunite Mount Novit 54529 5t PboT2Ko,lCao06Bao@(Al278Zno 16Cuo o6XSO4)l 48(POn)o5r(OH)5 e3Olo06 Potassichinsdalite Mount Novit 58305 7'. Pbo$Ko6A90 or(Alr-Feo.oCuo*Tioo4Zno @XPO4)os(SO.)o or(Asoo)om(OH)5 6rolo@ Ferrianhinsdalite Lake Moondarra 54559 6t Ceo2elG 2ecao 22lao,rSro,oNdo o.(Al..nzno o6XPOo)1 6r(5O4)o ,,(OH),4rclo M Potassic florencite . H+ attached to (PO4)ions not shown. *' Fe content reduced (see text) t Fe and Al contents reduced (see text). SCOTT:ALUNITE-JAROSITE FAMILY l8l

Table4. Compositions(wt%) of mineralsof the alunite-iarositefamily contaminated by ironoxides

Location Hilton Mount Novit Mount Novit Sampleno. 50377 54530 54535 No. of analyses sio, 3.29 4.54 0.41 0.52 0.61 1.48 Alro3 2133 19.96 22.75 21.39 28.31 25.52 Fe,O" 15.98 2151 10.13 15.04 3.78 10.82 KrO 2.86 273 182 1.47 1.82 1.53 CaO

Jolimont enabled determination of elemental contents down to 0.1-0.2 wt0/0.Owing to the possibility of overlap of the SKa andPbMa radiation on the energy-dispersivesystem, the wavelength-dis- persive systemwas used to determine Pb and SOr down to 0.05 and 0.2 wto/0,respectively. Samples from Pegmont and Fairmile were analyzedexclusively by wavelength-dispersiveX-ray spec- trometry before the Link systemwas available. Therefore, anal- family in these samples Fig. 1. Proterozoicoutcrop of the Mount Isainlier, showing yses of minerals of the alunite-jarosite Pb-Zndeposits and prospectssampled in this study. may not necessarilybe comPlete. Many of the alunite-jarositesoccur as composite grains with iron oxide, quartz, muscovite,and kaolinite inclusions.The SiO' contaminants betrays their presence, Isa (Fig. l), with outcropping samplesconsisting of weath- content of the latter three but in the goethite- and hematite-rich gossans,the extent of any ered phyllites cut by kaolinite veins. Much of the Zn oc- iron oxide contamination within the alunite-jarosite analysesis goethite, curs in and the alunite-jarosite minerals are Sr- not alwaysobvious becauseof possibleAl-Fe substitution within rich. The Pegmontand Fairmile depositsare volcanogenic the mineral itself. Thus, when compositions are reported in the and are associatedwith banded iron formations (BIF) in following sections,analyses with the lowest Fe contentsare taken amphibolite-faciesmetamorphic rocks south of Cloncurry asbeing the most pure, and valuesfor severalindividual analyses (Fig. l). Surfacesamples are often stained black by man- have been averaged. ganese oxides and consist of assemblagesof variable Data treatment amounts of goethite,alunite-jarosites, graphite, hematite, quafiz, pyromorphite, manganeseoxides, spessartite,and A total of 226 analyseshas been grouped into 52 alunite su- jarosite (23 representative kaolinite. pergroup and I 5 supergroupaverages averageanalyses are quoted in Table 3). However, even for these Mnrnoos analyses,much of the Fe content (and sometimesall of it, plus someof the Al) was superfluousto the requirementsof the struc- Anall'ticaldetails tural formula, ABj(XOo)r(OH)6.As the XOo anionsare the major Elementalcompositions were determined using the G-1O-keV structural units in alunite-jarosites,excess Fe was regarded as spectralrange of the Link energy-dispersiveX-ray systemat- being due to contamination, and mineral compositionswere cal- tachedto a MicroscanV wavelength-dispersivemicroprobe. Beam culatedon the basisof 2 mol (XOo) and up to 3 mol B per formula currentwas 5 x 10-sA, andthe voltage 20 kV. Theseconditions unit. Ifthe total B content exceeded3 mol, the trivalent content 182 SCOTT:ALUNITE-JAROSITE FAMILY

Sholc-hostcd (cxcludingDugold Rivcr) 0ugold River BIF-ossociotcd (PcAmontond Foirmila) o C E o

-az'= a' E

Fe3' in B sitcs (mol) Fig. 3. Histogramof distributionof Fer+(mol) in B sitesin samplesfrom northwestQueensland.

Fig.2. Monovalent relative to divalent occupancyof A sites eight samplesappears abnormal. Becauseof the "loose- in samplesfrom northwest Queensland. ness"of the stmcture(Botinelly, 1976),it is possiblethat "excess" A-site cations are adsorbed onto the alunite- was reducedby first excluding Fe and then, ifnecessary,Al. The jarosite structure. Alternatively, some of the surplus di- number of OH radicals present is simply the number required valent ions could be accommodated in B sites as in os- to achieve electrostaticneutrality in the formula. However, be- arizawaite-beaverite(Jambor and Dutrizac, 1983). Cu'?* causeofthe unknown extent ofprotonation ofPOl-, especially andZn2+, which are only 150/olarger than Fe3* (Table l), phosphates, in double the OH content may often be artificially have beenso accommodated(Table 3). However, the oth- low. er divalent cations in the alunite-jarosite type minerals The validity of this method of data treatment is shown by the Fe3+(Table l) and are unlikely fact that similar compositions were obtained when data from a are at least 500/olarger than singlesample that showeda rangeofFe contentswere treated in to be incorporatedin B sites.As the method of calculation this way (Table 4). Nevertheless,analyses of highly contaminated in this study does not preclude the possibility ofunana- alunite-jarositesare more likely to be in error than thosefor purer lyzed components in (XOo) sites, artificial overfilling of samplesand consequentlyhave not been used in calculatingthe the A sites is also possible. The most likely additional compositionspresented here. The abundancesofthe components component in this study is CO.2 , which is only slightly of the alunite-jarosite minerals are given in moles per formula smaller than SOi- anions (Table l) and has beenrecorded unit unlessotherwise indicated. in substantialamounts in plumbogummite (Fortsch,1967) and in lesseramounts in alunites(Simpson, l95l;Keller Rnsur,rs AND DrscussroN et al., 1967). Therefore, the effect of not analyzing for A-site occupation components like COI- probably causesthe "excess" of K and Pb are the most abundant constituentsin the A A-site cations, but additional work is required to resolve sitesof the alunite-jarositeminerals of northwest Queens- the problem completely. land (Table 3). When the A sites are partly occupied by divalent cationsrather than solelyby monovalent cations, B-site occupation total occupancy of the A sites generally falls well below In the shale-hosteddeposits at Kamarga, Dugald River, the line representingperfect one for one (A2+ : A+) sub- Jolimont, and about Mount Isa, all but three of the min- stitution (Fig. 2). The line of best fit suggeststhat two erals of the alunite-jarosite family are members of the types of substitution occur. Initially chargeis conserved alunite supergroup (Fig. 3). Some of the analyseswith by a divalent cation substituting for two monovalent cat- Fe3+( 0.05 mol could be artifacts reflectingthe method ions, i.e., A2+ : 2A+, as in Pb'z+substitution for 2K* in of calculation. However, even if all of the analyzed Fe going from jarosite to plumbojarosite. This processdom- were present in B sites, only nine additional sampleswould inates the region up to 0.2-mol A2*, aI which level 200lo be added to the jarosite supergroup. of the A sites are vacant (Fig. 2). Above this level of As the possibility of complete solid solution between divalent substitution, the data points reflect substitution Al and Fe in the trivalent B sites exists (Brophy et al., in the approximateproportions A2+ : 0.86A* (i.e., 0.9 1962),it is desirableto indicate further the relative pro- A2+ : 0.77 A*, Fig. 2), resulting in up to 140lovacancies portions of Al and Fe. Thus alunite supergroupmembers in A sites. with 0.5 { ['sr+ < 1.5 mol are referred to as "ferrian" In alunite-jarositeminerals, occupancyofA sitesis gen- and jarosite supergroupmembers with 0.5 < Al3+ < 1.5 erally greater than 70o/o(Fig. 2) but, as complete filling is mol as "aluminian" (seeTable 3). nncommon (Botinelly, 1976), the overfilling by >50/oin The majority of Fe-rich alunite-jarositefamily minerals SCOTT:ALUNITE-JAROSITE FAMILY 183

This study From thc Iitcroturc This study From thc lilcroturc . Shotc-hostcd somplcs o Noiurol olun ile -lorositcs . Sholc-hostcdsomplas o Noturololunatc- 6 Sho lc - hostcd somptes I Osorizowoite -beovcri tc 6 Shole-hostcdsomplas (mox.Fe) jorosites (moximum Fe) :ioted somples r Osorizou,qitc- -ossocioicd t BIF somplcs ond Foirmite) bcoveritc (Pcqmont ond Foirmila) a t vr I I l! ro o t o o a A loA o o r 'r a o 8l- l o o a I oq a l.oqo6 a onlj--l a laa o^ 6 l. . a - iMl..r;;;;l Etr 0'6Fu'o l- ir immiscibilitv|rYlflltsctD|ltlV ofoT iI ; o^ | ... ^ I :.- : . aol ruwQucenstonoi

a .f,.A a I 'o ^i4--S-.-J ' o-o I - 1.0 2.O 3'0 Fe3'inB sitcs (mol) Fig. 5. Divalentcations in A sitesrelative to Fe3+in B sites, showingextent of solid solutionfor northwest and a- | rmmrscrDrlrtyol I Queensland t othernatural samples (from the literatureas in Fig. 4). ^.,L o lNwouccnslond---* '"'- - ! 'uT | "' | laolsomplesi l.ar (XOo)3 > l.l mol (Fig. a). Similarly, o.zi{av'z:-: aA occursonly where L______Ji ! i lro. a A sitesmust be more than 800/ofilled by divalent cations lE 6 A lr ' to show continuous Al-Fe substitution (Fig. 5). Where O.Or!o.i-f.- o-l-1a1-1-1---f q-1--4 ---4 r0 20 30 (XOo)'- < l.l mol and ,{2+ < 0.8 mol, the extent of re3'inB sites (mot) miscibility of the northwest Queenslandsamples may be Fig. 4. Trivalentanions in XOo sitesrelative to Fe3*in B extendedby considering all or part ofthe Fe to be in the sitesfor northwestQueensland and other natural samples. Data B sites.Even then, a substantialgap remainswhere 0.15 < for alunite-jarositesfrom Simpson ( 1948; 195 1, p. 661)and Bro- (XOo)'- < 0.8 and 0.2 < A2* < 0.7. Only sample58349 phyet al. (1962).Dataforosarizawaite-beaverite from Kasymov (Black Star), which has (Zn + Cu) : 0.76 mol (Table 3), (1958),Van Tassel (1958), Taguchi (1961), Morris (1962),Ta- falls within the gap (Fig. 5), but even this sample would guchiet al. (1972),Cortelezzi (1977), and Paar et al. (l 980). plot outside the gap if Zn and Cu were consideredas Fe. Taken together, Figures 4 and 5 indicate that Al-Fe sub- occur at Dugald River, Pegmont, and Fairmile (Fig. 3), stitution is best developedwithin the alunite, hinsdalite, i.e., thereare far more ferrian alunite-jarositesin prospects plumbogummite, and lusungitegroups as well as between to the eastof Mount Isa than in the shale-and slate-hosted osarizawaiteand beaverite. Further work is required to depositsto the west. At Pegmont and Fairmile, the influ- determine whether the compositional gapsin the jarosite ence of pyromorphite, Pbr(POo)rCl, on alunite-jarosite and beudantite groups are real or merely sampling arti- formation (Taylor and Scott, 1982) and the larger grain facts. sizesofalunite-jarosites reducethe effectsofpossible con- Cu and Zn consistently occur in the B sites (Table 3). tamination by aluminosilicatesand iron oxides. Here the In osarizawaiteand beaverite,one-third of the B sitesmay maximum amount of "excessFe" excluded from the B be occupiedby Cu, with subordinateZn substitution (Ta- sitesis only 0.2 mol (comparedwith >3 mol in some guchi, 196l; Morris, 1962; Taguchi et al., 1972; Corte- shale-hostedsamples), and B sitesare often incompletely lezzi, 1977).More than 2o/oandup to 7.6o/oZn (by weight) filled Oable 3). As the extent ofAl-Fe substitution in these occurs in seven shale-hostedminerals of the alunite-ja- samplesis not subject to any possible uncertainty (as in rosite family in northwest Queensland (Table 3). Such the alunite-jarositesfrom the shale-hosteddeposits), the levels are equivalent to 5 to 210looccupancies of the B possibility of complete solid solution in B sites is dem- sitesand are up to double the 9o/ooccupancies previously onstrared(Fie. 3). reported in natural materials (Livingstone and Cogger, Complete solid solution in B sites has been observed 1966).Although Cu is preferentially incorporated relative in sulfate-richmembers of the alunite-jarositefamily, e.9., to Zn, the work of Jambor and Dutrizac (1983) demon- alunite andjarosite (Brophy et al.,1962) and osarizawaite strates the possibility of even higher Zn contents than the and beaverite. However, when the B-site occupancy of 3.80/othey reported. the northwest Queenslandalunite-jarosites is considered In northwest Queensland,more than 300/oof the anal- relative to valenciesin (XOo) sites,complete solid solution yses from shale-hosteddeposits have (Zn + Cu) > 0. I 184 SCOTT:ALUN ITE-JAROSITE FAMILY

. Shqle -hoslcd sqmplcs . BIF-qssociotcd somptes (Pegmont ond Foirmile)

E 0

o 0 c

(xol) 3-(mot ) Fig.8. A-siteoccupancy relative to (XO")-siteoccupancy for 06 08 r0 12 't1 16 selectedalunite-jarosite family minerals[from literaturevalues, (xoa)3-(mor ) recalculatedto 2(XOo).Source ofdata: 1, Brophyet al. (1962); 2, Cortelezzi(1977);3, Kasymov (1958); a, Kelleret al.(1967); Fig.6. (Zn + Cu)content ofB sitesrelative to trivalentanion Livingstoneand Cogger (1966); 6, McKie(1962);7, Melnikov contentof XO4sites in samplesfrom northwest 5, Queensland. et al. (1969);8, Morris(1962);9, Ossaka et al. (1982);10, Paar et al. (1980);I 1,Palache et al. (1951,p. 569);12, Schmetzer et mol (Fig. 6). Where0.5 < (XO")3 < 1.5mol, 500/oof the al.(1980); 13, Simpson (1938; 1948, p. 63;1951, p.661);14, samples have (Zn + Cu) > 0.1 mol. However, where Slansky(1977);15, Smith et al.(1953); 16, Taguchi (1961);17, Taguchiet al.(1972); 18, Van Tassel (1958); 19, Walenta et al. (XO";'- > 1.5 mol, (Zn + Cu) contentsare low (Fig. 6); (1982);20,Wise (1975); and2l, Scott(unpub. data). indeed the maximum Zn and Cu contentsrecorded in the literature for phosphate-richalunite-jarosites are 0.08 mol until (XOo)3- contents are about 0.45 mol. This gap cor- in philipsbornite(Walenta et al., 1982)and 0.07 mol in respondsto the region ofgreatest deficiencyin A-site oc- plumbogummite(Slansky, 1977), respectively. Thus, sub- cupancy (Fig. 2). As no literature values have been found stantial Zn and Cu substitution in B sites occurs prefer- to fill the gap (Fig. 8), it may possibly represent a real entially in sulfate-rich family members. The (Zn + Cu) compositional break. content also tends to increasewith Pb content, as in the one of the northwest analysesthat artifi cially prepared beaverite-plumbojarosite-hydro- Only Queensland plot significantly(>0. I mol) above the l:l (A'z++ Ar+) nium jarosite system(Jambor and Dutrizac, 1983). vs. (XOo)3-line, 0-P, is not Zn- or Cu-rich (Fig. 7). (This (XOn)-siteoccupation sample,50612 Fairmile, is the most sulfate-richof the Fairmile and Pegmont samplesbut was not analyzedfor Progressivesubstitution of trivalent for divalent anions Zn or Cu.) Osarizawaiteand beaverite,with extensiveCu is accompaniedby a concurrent changefrom monovalent andZn substitution in the B sites,plot well above the l: I to divalent cationsin A sites,i.e., A*83(XOo)i-(OU)u- trend (Fig. 8), but occupancyof the A sitesofthese samples A'z*B3(XO4)3-(XO"),-(OH[(Fig. 7). In the alunite and averagesonly 92o/o.Therefore, their electrostaticneutral- jarosite groups,there is a cluster of analyseswith (XO4)3- ity is apparently maintained by a combination of vacan- and ,A'2+contents from zero to 0.25 mol. Except for the cies in A sites and substitution of divalent Cu and Zn in Zn- or Cu-bearingsamples, above this level there is a gap B sites,as in the beaverite-plumbojarositesystem (Jambor and Dutrizac, 1983).In the northwestQueensland samples, however, these two mechanismsare superimposed Pr i upon the substitution of [A'?* + (XO4)3-] for [A* + (XO.1,-1 within the alunite, jarosite, hinsdalite, and beudantite groups. Analyses plotting well below the l:1 line in Figure 7 reflect partial occupation ofA sitesas a significant mech- anism for maintaining electrostatic neutrality, although BEUDANTITE GROUP not quite as significant as in schlossmacherite(point 12,

. Shole-hostcd sqmples Fig. 8). Many of the northwest Queenslandanalyses, in- r BIF-ossocioted sompl?s (Peqmont ond Foirmile) cluding those with (POo)'- > I mol, have only minor Cu a Zn5rCu>010mol ionic neutrality is maintained o Co-orRE-rich and Zn contents so that mostly by a combination of the A-site vacancy and sub- (x01)3-(mor) sritution of [A,+ + (XO4)3-]for [A' + (XO")'?-]. Fig. 7. Divalent and trivalent cations in A sites relative to Further trivalent anion substitution occurs either with A'z+B3(XO4)3-- trivalent anions in XOo sitesin samplesfrom northwest Queens- associatedtrivalent A-site substitution, land. Line 0-P representsperfect substitution [Az+ + (XO4)3 ] (XO.F-(OH)6 - A3+B3(XO.)]-(OHL' or, where the A site for [A* + (XO")t-] as in alunite - hinsdalite. remains occupied by divalent cations, by protonation of SCOTT:ALUNITE-JAROSITE FAMILY 185 oneof the trivalent anions,A'z+B3H(XO4), (OH)6. In Fig- in the A site balancesthe presenceof a secondtruly tri- ure 7, (POo)3-and (POTOH)2 are not distinguished,but valent phosphate radical. Therefore, it is suggestedthat the absenceof samples with monovalent A and (POo)/ the REE-bearing double phosphates should be distin- (SO")> I (i.e.,along the abscissa)implies that (PO.OH)'- guishedfrom the plumbogummitegroup (asdefined above) only occurswhere phosphatespecies are the major anions as the "florencite group." in the (XOo)sites, i.e., in the "double phosphates"of the Substitution of Pb2* for K* in alunite can also be bal- plumbogummite, lusungite, and, possibly, florencite ancedby replacingup to one-third ofthe trivalent cations groups. When (PO.) > I mol, considering about half the in B sites by divalent Cu and Zn, as in osarizawaiteand total phosphateas (POTOH)'z would also have the desired beaverite,Pb(Al,Fe,Cu)3(Soo)r(OH)6. Some minerals of result of elevating the low (OH) contents of plumbo- the alunite,jarosile, and hinsdalite groupsfrom northwest gummite and lusungite samples to more normal levels, Queenslanddisplay substantialdevelopment of this trend, e.9.,at Pegmont(50619), (OH) contentswould be raised plus partial occupancy of A sites (as in plumbojarosite) from 4.04,4.03,and 4.13mol (Table3) to 5.00,4.81, superimposedon the substitution of (Pb'z*and PO?-) for and 5.1I mol, respectively. (K* and SOtr-).Znrather than Cu is the dominant divalent Where (XOo)' > I mol, divalent cations usually oc- ion, with up to 0.62-mol (or 7.6 wto/o)Zn occurring at cupy more than 900/oof the A sites but, except for solid Black Star, Mount Isa. Theseobservations suggest that B solution in the Ca-Sr-Ba-REEphosphates at Jolimont and sites can be at least partly occupied by Cu and Zn in Lake Moondarra and between plumbogummite and lu- sulfate-rich types. sungiteat Pegmontand Fairmile, double phosphates[i.e., Becauseof the method of calculation of the formulae, (POo)> 1.5 moll are not common in northwestQueens- substitution of Fe for Al could have been artificially min- land (Fig. 7). As seenabove, only the REE-rich members imized, but even under theseconditions, up to 0.84-mol like florencite, CeAl,(POo),(OH)u,are true double phos- Fe (58305,Mount Novit; Table 3), representing28o/o oc- phateswith the potassicvariety (54559) from LakeMoon- cupation of B sites, occurs in shale-hostedalunites (Fig. darra (Table 3) being the sole example found during this 3). However, at Pegmont and Fairmile, where the effect study. Most apparent double phosphates are, in fact, of possible effors in B-site occupancyis minimal, Fe-Al members of the plumbogummite and lusungite groups intersubstitution is extensive. Therefore, the composi- where up to 500/oof the (POo)3 occurs as (PO3OH)'z tions of alunite-jarositesfrom northwest Queenslandin- Minerals of the alunite-jarosite family from the shale- dicate that complete Fe-Al solid solution may occur in B hosted deposits of northwest Queensland contain low sites, especially in the alunite, hinsdalite, plumbogum- phosphatecontents, but thosefrom Pegmontand Fairmile mite, and lusungite groups. usually have (POo) > I mol (Fig. 7). The latter group are from a phosphatic-volcanogenicassociation (Taylor and RncovrunNDATroNS FoR cLASSIFICATIoN Scott, 1982)where S content is relatively low, but even To prevent a proliferation of names for minerals of the in that environment, double phosphatesare not common. alunite-jarosite family, the following rules for classification and systematic naming are proposed for minerals A, B, lNo (XOJ suBsrrrurroN MoDES- with the generalformula AB3(XO4)r(OH).:(l) subdivision A sunlunv into alunite and jarosite supergroupsbased on dominant Substitutions of A2* for A* and (XOo)3 for (XOo)'z Al or Fe occupation of the B sites,respectively (Table 2); are not independent. In Pb-Zn gossans of northwest (2) (XO4)3- < 0.5 mol-alunite or jarosite groups; (3) Queensland,one Pb2+cation may substitute for two K* 0.5 < (XOo)3 < 1.5mol-hinsdaliteorbeudantitegroups; cationsin the A sitesof alunite, KAl3(SO4)r(OH)u.The- (4) (XO4)3-> 1.5mol-(a) plumbogummiteor lusungite oretically, suchreplacement could be extendedto produce groups if A-site occupancyis dominantly divalent or (b) an Al analogue of plumbojarosite with the formula florencite group if the A site is primarily occupied by Pb'5tr05A13(SO.),(OH)6,but in practiceonly 400/oof the trivalent cations;(5) if a minor B-site elementexceeds 0.5 K* is lost in this manner, giving the A-site composition mol, appropriate adjectival modifiers are useful, e.g., fer- K 6Pb02n0 ,. In ttiis compound, half ofthe resultantempty rian, aluminian, zincian, etc.; and (6) inclusion of more A sites (i.e., 100/ooftotal A sites) are gradually filled as than 0.05 mol of a minor cation in the A sitesjustifies an sevenPb2+ replace each remaining six K* ions, giving the appropriateadjectival modifier to indicate the most abun- A-site composition Pbonlo ,. Concurrent with the A-site dant of the minor cationsthowever, if a modifier is applied changes,(POo)'- replaces (SO.)'z to produce PboeAl3- under rule 5, rule 6 should not apply. (PO.XSO"XOH).,i.e., hinsdalite,with 100/ovacancies in Becauserules I to 4 implicitly define limits for already the A sites. establishedminerals, the approval of the IMA Commis- Complete substitution of (SOo)'z by (POo)3 gives sion on New Minerals and Mineral Names has been ob- plumbogummite, PbAI.H(PO4)r(OH)6.As one of the tained. (POo)' radicals is actually divalent (PO3OH)'z-(cf. Ra- The conceptof naming accordingto the proportions of doslovich, I 982), no further changein A sitesoccurs, and endmembers,as used by McKie (1962), is not recom- divalent occupancyof the A sitesis often only 900/0.Haw- mended becausewith multiple speciesin the A, B, and ever in florencite, CeAlr(POo)r(OH)u,the trivalent charge (XOo) sites, the names of many of the alunite-jarosites 186 SCOTT: ALUNITE-JAROSITE FAMILY reported above would involve more than six endmem- Brophy, G.P., and Sheridan,M.F. (1965) Sulfatestudies. IV. The bers. In addition, when there are several anions in the A jarosite-natrojarosite-hydroniumjarosite solid solution series. Mineralogist,50, I 595-1607. sites and mixed cations in (XOo) American the sites, ambiguities Brophy, G.P., Scott, E.S.,and Snellgrove,R.A. (1962) Sulfate can arise in determining endmembers.Furthermore, be- studies.II. Solid solution betweenalunite and jarosite. Amer- causeofnamed phosphate-sulfatesand double phosphates ican Mineralogist,47, 112-126. for elements like Ca, Pb, and Sr, the description would Cortelezzi,C.R. (1977) Occurrenceof osarizawaitein Argentina. often not be unique. NeuesJahrbuch fiir Mineralogie Monatshefte, 39-44. Fortsch, E.B. (1967) "Plumbogummite" from Roughten Gill, Under these rules the only minerals of the alunite-ja- Cumberland. Mineralogical Magazine, 36, 530-5 38. rosite family apparently not specificallyprovided for, are Hladky, George,and Slansky, Ervin. (1981) Stability of alunite those with only 500/oof the A sites occupied, e.g., plum- minerals in aqueoussolutions at normal temperatureand pres- bojarosite, or substantial amounts of divalent ions in B sure. Bulletin de Min6ralogie, 104, 468-477. and Dutrizac, (1983)Beaverite-plumbojarosite sites,e.g., the osarizawaite-beaveriteseries. However, Jambor, J.L., J.E. un- solid solutions.Canadian Mineralogist, 21, 101-113. der rules I and 2, these examples are merely abnormal Kasymov, A.K. (1958) Beaveritein central Asia. Uzbekskii Geo- members of the alunite or jarosite groups; where neces- logicheskii Zhvna| 2, 83-87. sary, Cu and Zn should be consideredequivalent to Fe. Keller,W.D., Gentile,R.J., and Reesman,A.L. (l 967)Allophane and Na-rich alunite from kaolinitic nodules in shale.Journal Nnw NrrNnn-q.Ls of SedimentaryPetrology, 37, 215-220. Livingstone, A., and Cogger,N. ( I 966) A new British locality for No evidencefor the existenceof PborAlr(SOo)r(OH)u, beudantite:Sandford Hill, Somerset.Mineralogical Magazine, the Al analogueof plumbojarosite, was found, but plum- 35,l0l3-1016. bian alunite with compositions closeto the ideal formula McKie, Duncan. (1962)Goyazite and florencitefrom twoAfrican Magazine, 281-297. Pb' (50377, carbonatites.Mineralogical 33, 5Iq 5Al3(SOo),5(PO4)o s(OH)u does occur Hil- Melnikov, V.S.,Fishkin, M.U., and Kostenko,A.I. (1969)A new ton;58244, Bernborough;Table 3), with the K and (POo) mineral variety in the isomorphic row of alunite-hinsdalite. contents essential for electrostatic neutrality. Although Lvov Universitet Mineralogicheskii Sbornik, 23, 5846. minerals with 750lodivalent and 250/otrivalent (XOo) site Morris, R.C. (1962)Osaizawaite from WesternAustralia. Amer- occupancy or vice versa have been defined previously ican Mineralogist,47, 1079-1093. Ossaka, Joyo, Hirabayashi, Jun-ichi, Okada, Kiyoshi, Koba- (e.g.,schlossmacherite and philipsbornite;points 12 and yashi, Ryuki, and Hayashi, Tamotsu. (1982) Crystal structure 19, Fig. 8), they were defined for their HrO-A1-SO. and of minamiite, a new mineral of the alunite group. American Pb-Al-AsO.contents, respectively (Schmetzer et al., 1980; Mineralogist,67 , ll4-ll9. Walentaet al., 1982).Plumbian alunite can be considered Paar,W.H., Burgstaller,H., and Chen, T.T. (1980)Osaizawaite- intergrowthsfrom SierraGorda, Chile. Mineralogical an intermediate between alunite, KAl3(SO")r(OH)u, beaverite and Record,11, 101-104. hinsdalite, PbAl3(SO4)eOoXOH)6,however, its Pb, Al, Palache,Charles, Berman, Harry, and Frondel, Clifford. (1951) and SOocontents could justify its classificationas the Pb Dana's systemof mineralogy, 7th edition, vol. II. Wiley, New analogueof alunite and hence a new mineral. Similarly, York. (1982) gorceixite in the aluminian lusungite(50619, Pegmont, Table 3) has a Radoslovich, E.W. Refinement of structure Crn. Neues Jahrbuch fiir Mineralogie Monatshefte, 446-464. formula closeto PbFerH(POo)r(OHL,the Fe analogueof Ramdohr, Paul, and Strunz, Hugo. (1978) Klockmann's khr- plumbogummite, and also qualifiesas a new mineral. Un- buch der Mineralogie, 16th edition. Ferdinard Enke Verlag, fortunately, the compositions of these minerals change Stuttgart. over very small distances,thus preventing adequatechar- Schmetzer, Karl, Ottemann, Joachim, and Bank, H. (1980) Schlossmacherite,a new mineral of the alunite-jarositegroup. acterizationof their properties. Neues Jahrbuch fiir Mineralogie Monatshefte, 215-222. Simpson,E.S. (1938) Contributions to the mineralogy ofWestern AcrNowr-BocMENTS Australia. Royal SocietyofWestern Australia Journal, 24,107- This workgrew out ofthe extensivestudy ofgeochemical fea- t22. turesof gossansand ironstonesin the Mount Isa Inlier, com- - (1948)Minerals ofWesternAustralia, vol. l. Government mencedby G. F. Taylor,CSIRO Division of Mineralogy,in 1972. Printer. Perth. W.A. The logisticsupport of Mount Isa MinesLtd, CarpentariaEx- - (1951)Minerals ofWesternAustralia, vol. 2. Government plorationCompany, CRA ExplorationPty Ltd, NewmontPty Printer. Perth. W.A. Ltd, andICI AustraliaLtd is gratefullyacknowledged. Discussion Slansky, Ervin. (1977) Plumbogummite from Ivanhoe mine, with pastand presentgeologists from thesecompanies and col- Northern Territory, Australia. NeuesJahrbuch fiir Mineralogie leaguesin CSIROprovided the basis for this study.L. F. Brunk- Monatshefte,45-53. horstand K. Kinealyprovided instruction and maintenancefor Smith, R.L., Simons,F.S., and Vlisidis, A.C. (1953)Hidalgoite, theelectron microprobe. A reviewofan earlierdraft ofthis paper a new mineral.American Mineralogist,38, I2I8-I224. by E.H. Nickel(IMA Commissionon NewMinerals and Mineral Strunz,Hugo. ( I 978) MineralogischeTabellen, 7th edition. Aka- Names)is particularlyappreciated. Suggestions from thereview- demishe Verlagsgesellschaft.Geest und Portig K-G, Leipzig. ers(T. Botinellyand J. L. Jambor)have also improved the paper. Szymanski,J.T. (1985) The crystal structure of plumbojarosite PblFe,(SOo),(OH)ul'.Canadian Mineralogist, 23, 659-668. RrrnnnNcns Taguchi,Yasuro. (1961) On osarizawaite,a new mineral of the alunite group, from the Osarizawamine, Japan.Mineralogical Blount,A.M. Q97\ The crystalstructure of crandallite.Amer- Journal(Japan), 3, 181-194. icanMineraloglst, 59, 4I-47. Taguchi, Yasuro, Kizawa, Yoji, and Okada, Noboru. (1972) On Botinelly,Theodore. (1976) A rewiewofthe mineralsofthe alu- beaveritefrom the Osarizawamine. Mineralogical Journal (Ja- nite-jarosite,beudantite and plumbogummitegroups. U.S. pan),10,313-325. GeologicalSurvey Journal of Research,4, 213-216. Taylor, G.F., and Scott, K.M. (1982) Evaluation of gossansin SCOTT: ALUNITE-JAROSITE FAMILY 187

relation to lead-zinc mineralization in the Mount Isa inlier, ipsbornite,a new mineral ofthe crandalliteseries from Dundas, Queensland.Bureau of Mineral ResourcesJournal of Austra- Tasmania.Neues Jahrbuch fiir Mineralogie Monatshefte, 1-5. lian Geologyand Geophysics,7, 159-180. Weast, R.C. (1968) Handbook of chemistry and physics, 49th -(1983) Weathering of the lead-zinc lode, Dugald River, edition. Chemical Rubber Company, Cleveland, Ohio. northwest Queensland.II. Surfacemineralogy and geochem- Wise, W.S. (1975) Solid solution between the alunite, wood- istry. Journal of GeochemicalExploration, 18, I I 1-130. houseite, and crandallite mineral series.Neues Jahrbuch fiir Van Tassel, R. (1958) Jarosite, natrojarosite, beaverite, leon- Mineralogie Monatshefte, 540-545. hardtite, et hexahydrite du Congo belge. Institut Royal des SciencesNaturelles de BelgiqueBulletin, 34, l-12. Mam;scrrrr REcETvEDMencn 23, 1986 Walenta, Kurt, Zwiener, Martina, and Dunn, P.J. (1982) Phil- Mexuscnrrr AccEprED SBrtsr"rsrR.2, 1986