American Mineralogist, Volume 69, pages 358-373, i,984 Titanian taramellites in westernNorth America JosN T. Arrons California Division of Mines and Geology Sacramento, California 95814 eNo Aoorp Passr Department of Geology and Geophysics University of California, Berkeley, Califurnia 94720 Abstract Taramellite,BaolFe3+,Ti4+,Fe2*,Mg;.1B2siEo27)o2cl*, until recently known only at the type locality, Candoglia in ltaly, has been found together with many other Ba-silicatesat eight scattered localities in western North America. All of the taramellites from these localities are highly titanian and those in which TilFe exceeds unity may be called titantaramellite. Contrary to the formerly current description, taramellite is not at all fibrous, but occurs in tabular to equidimensionalorthorhombic crystals, in some occur- rences with excellent morphology. Six of the North American occurrencesare at or close to the contacts of large granitic bodies where zonesor lenseswithin metamorphicrocks are composed largely of Ba-silicates among which sanbornite, BaSi2O5,is dominant. At one locality in Santa Cruz, California, taramellite has been found in large, ragged,crystals in a metamorphosedlimestone which carries a wide variety of sulfidesand sulfosalts. Finally, taramellite is a minor constitutent in complex veins in Franciscan enclaveswithin a large ultramafic body in San Benito County, California. Analyses and properties of taramellites at all eight localities are reported together with decriptions of each locality and data on the associatedminerals. Historical introduction Subsequentlytaramellite was recognized in a deposit of Ba-silicates in Tulare County, Calif., and in an occur- Taramellite was describedby Tacconi (1908a,l90gb) as rence in very limited amount with colorless benitoite in a new silicate of barium and iron occurring as acicular the Clear Creek area, San Benito County, California crystals or fibrous aggregatesin contact metamorphosed (pers. comm. E. Oyler and R. C. Erd, 1977).The pres- calcareousrocks at Candogliain the Valle del Toce, Italy. ence of taramellite among numerous other Ba-silicatesat For many years thereafter no additional occurrences of the La Madrelena mine in northern Baja California had taramellite were recognized as such. Montgomery (1960; been recorded by J. R. Hinthorne (1974,p.2l). All of Thompson and Montgomery, 1960; Montgomery et al., theseeight localities were listedby Pabst(1978, Table l). 1972)recognized taramellite as well as other Ba-silicates Ih December of 1976 Dr. A. Kato, chairman of the from a contact metasomaticdeposit near the headwaters I.M.A. Commission on New Minerals and Mineral of the Ross River in the Yukon Territory, close to the Names, having noticed the high Ti content of Fresno border with the Northwest Territories. Montgomery County taramellite (as recorded by Mazzi and Rossi, (1960) also reported the identification of taramellite in 1965,footnotep.248), wrote to one of us (A.P.) suegest- specimensfrom the type locality of sanbornitein Maripo- ing that the California taramellite should be considered..a sa County, California. Montgomery firmly establishedthe new speciesas a titanium dominant member of taramel- identity of taramellite from Candoglia, Ross River and lite", the original taramellite from Candoglia,Italy, being Mariposa County by recording closely agreeing X-ray iron dominant. At the same time Dr. Kato informed us powder patterns for each. that he and Matsubara had "found a V3* analogue of The first published reference to the occurrence of taramellite" in Japan which was subsequently named taramellite in California was made by Alfors et al. (1965, nagashimalite(Matsubara and Kato, 1980). p. 315) in which the occurrences in Mariposa County, Accordingly we made a presentationto the I.M.A. Fresno County, and Santa Cruz County, California, as Commission proposing the name titantaramellite for Ti- well as that in the Yukon Territory, were mentioned. dominant taramellitessuch as someof those from Califor- 0003-004x84/0304-0358$02.00 358 ALFORS AND PABST: TITANIAN TARAMELLITES 359 Table l. Materials available for each locality material and from Candogfia but two small specimens' Even so, it was possible to obtain adequateamounts of Number Locality l,laterlal 'I taramellite from each locality for determination of com- RossRlver 2 small speclnens,g. 2 and lO! 9r. ' YukonTerrltory glfts of the late Professor R. ll. position, X-ray difraction, some physical properties and Thompson(vancouver) 1950. morphology. Extensive observations on associatedmin- 2 Trumbull Peak Numerous'1950 speclnens collected by A.P. Ihrlposa County,Cr and by Dr. R.l,l.Douglass 1953, erals and thin section study of the Ba-silicate rocks were plus comerclally obtalned speclmens, carried out for all localities except l, 8 and Candoglia. In 3 RushCreek, our owncollectlons plus a superlor Fresno County, Ca speclmenglven by l!r. Forrest E, these casesthin sections could not be used and observa- CuretonII of Stockton' Ca]lfornla tions on associatedminerals were necessarily so limited 4 8i9 Creek, our owncollectlon plus superlor specl- Fr€sno County, mensglven by l,lr. Cureton and by l,lr. that they may not be representative. Materials available Robert E. l{alstron. for our study are listed in Table l. 5 ChlckencoopCanyon, Spslmens collected by staff msnbers TulEre County,Ca of the Callfornla Dlvlslon of lllnes and Geology, mostly by Robert l'latthews. Chemical comPosition 6 La lhdrelena mlne, Thr€e speclmensprovlded by the late (1908a, gaJaCalifornia ProfessorE.C. A'lllson (1970), speci- In early analytical work on taramellite, Tacconi ilexico menscollected by lillss JosephineL. Mazzi (1957),Mazzi and Rossi (1965,footnote p. Scripps received fron l{.C. Chesteman 1908b), ('1977)and specimensobtalned from 248), Cl and B2O3 were not noted and, at first even mlneral dealers Sl Frazier (Berkeley, 1970)and David Nfl (stevensville, titanium was not recognized. With our proposal to the l'lontana, 1974), I.M.A. Commission in 1977we submitted the results 7 Kalkar quarry, Specimensprovlded by EugeneGross santa cruz, Ca (1963)and by A.P. (1964)and superlor recorded in column 3 of Table 2 which were based on speclmensprovlded by l4r. J.F. Cooper taramellite at the (tlatsonvl].le,Ca 1973) and by ilr. Gail analytical work done on Fresno County E. Dunning(Sunnyvale, Ca 1979) plus California Division of Mines and Geology, San Francisco, several purchasedfrcm t{inerals Unllnlted (ilr. RalPh l'lerrll l ). in 1965 (Table 2, col. l) and at the U. S. Geological Mctor claim One specinen lent by f'lr. Ed 0y'ler (san Survey,Washington, D. C. in 1968(Table 2, cols. 2 and San Benito County, lilartin, Ca). Ca 2a); BzOzand Cl being recognized as essential constitu- Candoglia,Italy - one speclmen,ca. 3L gr., from the lluseo ents. The formula proposedwas Baz(Ti,Fe2*,Mg,Fe3*, Civicb dl storTt Natuiale, l'lilano' pro- vided by Professor F. ilazzi (Pavia) and Mn2+)zBSi+Or4(Cl,OH).Montgomery (1960)had record- rrc smal'lspeclmens, 1.3 and 15.8 gr'' ed a spectroscopic analysis of taramellite in which the ' BRGiIspecimen 6718 provlded by Dr. J. t'lantienne(Or'l €ns, France). major elements were given as Ba, Fe, Ti, Si, the minor elementsas Mg, Ca, B and the trace elementsas Mn, Sn, Cu, Ag, Pb, Zn, Na and Al. nia. The new mineral and name were approved by the For the present study a wet chemical analysis was I.M.A. Commissionin January, 1978,by votes of l8-0 obtained on a 2.6 gram sample of taramellite from the and l7-l respectively. At the suggestionof Dr. Michael Rush Creek area, Fresno County, California. This source Fleischer we immediately after proposed to the Commis- sion that the new mineral be named taramellite-(Ti). This Table 2. Previous analysesof taramellites suggestionwas not accepted, the vote being "Yes 4, No 5. Abstention 1." l2 2a334 c.D.!t.G. u.s.6.5. Reported tr Atric There are now known at least ten occurrences of I 965 1968 l.f,.^. Cil. ProDortlons They are: taramellite x-ray 1977 members of the taramellite series. spec.anal. (Fe-dominant)at Candoglia,Italy, the type locality; naga- (V-dominant) Mogurazawa mine, Kiryu Si02 3il.t 3il.l Si 16 shimalite at the FeZ03 1.2 1.2 Fe+3 o.ts City, Gumma Prefecture,Japan; and eight occulTencesof Fe0 4.0 a-0 Fe+2 1.57 Ba0 4{t.8 (r.8 Ba 7.50 highly titanian taramellite in western North America, Ti02 I 0.4 10.{ Ti 3.67 Ca0 0.23 O.23 Ga 0.ll some of which merit the name titantaramellite (Ti-domi- tlgo 1.7 1.7 ll9 l.l9 nant). H2(}r o-2 l,lno 0.16-0.30 0.21 0.16 0.21 th 0.(B cl |.8 1.9 cl l.5l 8203 4.3 4.83 4.3 I 3.118 Material -H20 0 Ig. loss 1.9 For this study we have beenable to examine specimens (r000"c) F 0.12 't.00.12 0.18 from all the North American localities and from Candog- (Al,v,cr)z0g 1.0 lia. We have collected extensively at localities 2, 3, 4 and Al203 0.19 Crl0a 0.15 7 and have been able to draw upon the collections at the Vzbr- 95S o-22 T6:T5' less 0lF2+01C12 - 0.05 --E;B 0.i18 California Division of Mines and Geology, San Francisco, 9-e.3Tr for specimensfrom these localities and from locality 5. Though we had ample material from locality 6 we have no Colum I Unpubllshed r€sults of l-ray spectmgraphic deteminatlons at C.D.14.G. personal acquaintancewith this locality and specimens 2a Yalries given in this colun are based on values Eported in ppn fiem €mission spec. anal.i additimnlly found Zr 3{Xl ppn' were obtainedboth from private and commercial sources. Sc, Sn and Sr each 2m pptr. tlb 100 ppr, Y 20 pm.