DOCSLIB.ORG

Coexisting Glaucophane and Riebeckite- Arfvedsonite

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Coexisting Glaucophane and Riebeckite- Arfvedsonite MINERALOGICAL NOTES THE AMERICAN MINERALOGIST, \TOL. 55, MAY_JUNE, 1970 COEXISTINGGLAUCOPHANE AND RIEBECKITE- ARFVEDSONITEFROM NEW CALEDONIA Purr-rppe M. Bracx,l Departmentof Mineral' Sciences,Smithsonian I nstitution, W ashingtonD.C. 20560 Assrnec:f Electronmicroprobe analyses are givenfor coexistingglaucophane and riebeckite- arfvedsonitefrom a lawsonite-bearingmetabasalt. Possible origins of the amphiboleas- sociationare discussed. Relationships between coexisting sodic and calcic amphiboles are now well documented (Klein, 1968b; Himmelberg and Papike, 1969), but there have been few records of coexisting sodic amphiboles, and phase relations within the complex alkali amphibole system are still not well understood. During a study of amphiboles in the New caledonian blueschists,an example of coexisting glaucophaneand riebeckite-arfvedsonitewas found in a metabasalt outcropping lawsonite-albite bearing pelitic schists of the Pilou Formation (Espirat and Millon, 1965) 1 km east of Col de Crbve-coeur. Thin sectionsof the metabasalt (10811) show relic phenocrystsof augite overgrown by glaucophane,lawsonite, chlorite, accessoryalbite, and quartz. Riebeckite-arfvedsonite constitutes less than 0.2 modal percent of the rock and occurs most commonly as small green blebs averaging 20 microns in diameter, enclosedwithin glaucophanecrystals, or rarely as larger more regular anhedra incompletely surrounded by individual glaucophanes(Fig. 1). Chemically and optically the contact. between the two amphiboles is sharp, but cleavagespersist through both amphiboles (Fig. 1.) indicating that the two phases are in crystallo- graphic continuity. The glaucophane shows the following pleochroic schemeand orientation:a:colourless; 0:violet; t:blue; b:P; cA"l: 5o; while the riebeckite-arfvedsonitehas: a:deep bluish green;B:deep olive greenl yellowish green; 6:7; c/\a--6o. No exsolution lamellae have":pale been observed in either amphibole. The two amphibole phaseswere analysed with an A'R'L'-E'M'X' electron microprobe using the standards and analysing procedures dis- cussedby Klein (1968 a,b). The analysesare presentedin Table 1' Es- timated errors are 3 percent for major and 5 percent for min or constit- uents. No attempt has been made to estimate the Fez+:Fe3+ ratio; the analyseshave been recalculatedanhydrous on the basis of 23 oxygensper r Present address: Department of Geology, Auckland university, Auckland, New Zea- land. r062 MINERALOGICAL NOTES Frc. 1. Dark riebeckite-arfvedsonite anhedra partially surrounded by lighter glauco- phane (center), and small riebeckite-arfvedsonite bleb (A) enclosed within glaucophane (lower left). (X500). unit cell assumingtotal iron as Feo. A knowledgeof the oxidation ratio of the amphiboles and subsequentcalculation of part of the iron as Fe2o3 will have the effectof reducingSii" and henceAl"i (coordinationnumber 6) but will not radically change other values. The optical orientation, pleochroicscheme and formula which can be derived from the microprobe analysis of the iron-rich amphibole are al- Tarr,r 1. couposrrroN ol conxtsrrxc Gr-aucopnaNe axr Rtnnncxrtr-Aru.l,lDs,Nrre Glauc. Rb-Arfv. Rb-Arfv sio, 55.2 502 Si 7.72 8.03 TiOz 0.1 0.5 AIi" o.28 AhOr 9.7 t.7 IreO, 1)4 30.4 Al"i 1.321 034 MnO 0.2 u.5 Ti -l I 0.071 Mgo 12.0 s 3.2 Fe2+ 1.4s fs .2e 4.o7ls.2e CaO r.7 14 Mn 0.021 0.071 NurO 7.0 5.4 Mg 2.50) o.76) KrO 2.0 Total 98.3 96.3 Ca 0.2.51 0.411 Na 1.e0f2.ls r.6712.48 K - ) 0.40J " Total iron calcuiated as FeO. MINERALOGICAL NOTES 1063 most identical to the data given for arfvedsoniteby Miyashiro (1957),but according to the later classifi.cationscheme of Borg (1967) the amphibole with its A site occupancy of ) 0.4 should be called riebeckite-arfvedsonite and Borg's terminology is followed here. Recent oxygen isotope work (Taylor and Colemen, 1968) has shown that lawsonite bearing blueschists crystallized at temperatures of 200- 400"C. The riebeckite-arfvedsonite bearing metabasalt occurs close to the lawsonite isograd in the lower grades of the New Caledonian blue- schists and probably crystallized in the lower part of the temperature range given by Taylor and Coleman (1968). The relations between members of the glaucophane-riebeckiteseries are well known and solid solution between end membershas been demon- strated by a number of authors (Miyashiro, i957;norg, 1967;Coleman and Papike, 1968). A complete solid solution series between riebeckite and arfvedsonite has been synthesizedby Ernst (1962) who observedno exsolution between synthetic end members at temperatures as low as 4200,c. The coexistence,at low temperatures, of two amphiboles which are known to form part of a solid solution seriesunder a wider range of P-? conditions is interesting and a discussion of the possible origins of the associationis warranted. The riebeckite-arfvedsonite is unlikely to be a relic igneous mineral since (to this writer's knowledge) sodic amphiboles are unknown in ba- salts. Primary igneousamphiboles do occur in the lower Tertiary basalts of northern New Caledonia but in all casesthey are kaersutitic horn- blendes. Chemical analysisof the metabasalt (SiOz:49.0; TiOr:2'0; AlO3: 18.5;Fe2O3: 4.2;FeO:4.7; MnO:0.14; MgO: 7'4;CaO:10'3; Na2O: 3.0; KrO:0.05; P2Q6:Q.08;HrO*:0'5) showsit to be a normal tho- Ieiitic basalt, compositionally similar to other basalts in the district. Metasediments adjacent to the basalt are fine grained lawsonite-albite phyllites, completely lacking in sodic amphiboles. There is no evidence, either from the composition of the metabasalt or from the surrounding metasediments, to suggest that the rocks may have been subjected to percolating iron-rich waters capable of crystallizing a riebeckitic am- phibole prior to the onset of blueschist metamorphism' The metamorphic history of the New Caledonianblueschist belt is very simple, and there is no evidencefor more than one metamorphic event. The association of riebeckite-arfvedsonite with glaucophane could be interpreted as due to a change in one or more of the physico-chemical variables during the metamorphism although if this were the case a gradual chemical transition between the two amphiboles would be ex- expectedrather than the observed sharp chemical and optical contacts. r064 MINERALOGICAL NOTES Ross, el al. (1969) have described an exsolution sequenceleading to the production of homogeneouspatches of an exsolvedphase within the host clinoamphibole. Such a processcould possibly explain the association and textural relations of the riebeckite-arfvedsonite and glaucophane. However, exsolutionlamellae have not been observedin alkali amphiboles although Sahama (1956) has interpreted optical anomaliesin natural arfvedsonites as exsolution features. There seemsto be no convincingexplanation for the coexistenceof the riebeckite-arfvedsonitewith glaucophaneand hencethe question whether the two amphiboles are an equilibrium or a disequilibrium assemblage must remain unresolved.Nevertheless, it should be pointed out that in the event that the two amphibolesare an equilibrium assemblage,the data presentedhere would indicate that a solvus exist between the riebeckite-arfvedsonite solid solution series and at least the aluminous members of the glaucophane-riebeckitesolid solution seriesunder the P-? conditions of the low temperature lawsonite-bearingblueschist facies. Acr<Nowlrocrurxts I am grateful to Dr C. Klein (Harvard University) for the amphibole microprobe standards and to Mr T. H. Wilson (Auckland University) for the chemical analvsis of the metabasalt. RrlrnpNcns Bonc, I. (1967) Optical properties and cell parameters in the glaucophane-riebeckite series. Co ntrib. M i.ner ol. P etrol o gy, 15, 67-92. Cor.rurN, R. G. eNo J. J. Parrxr (1968) Alkali amphiboles from the blueschists of Caza- dero, California, f. Petrology, g, 105-122. EnNsr, W. G. (L962) Synthesis, stability relations and occurrence of riebeckite and riebec- kite-arfvedsonite solid solutions. f . Geol.70, 679-736. Esrrner, J J. eNo R. MrlroN (1965) Carte et notice explicative sur la feuille pam-Ou6goa. Ca.rtegAologi,que d l' 6chel,l,edw 1/ 50000 Territoire de I,aN ouvel,l,e-Caleilonie. rrruuelrrnc, G. R. aul J. J. Parrrc (1969) coexisting amphiboles from blueschist facies metamorphic rocks. L Petrology,lO, 102,114. Klnrw, C. (1968a) Coexisting amphiboles. f . Petrology, g, 281-330. - (1968b) Two amphibole assemblages in the system actinolite-hornblende-glauco- phane. Amer. MineraJ.54, 212-237. Mrvesnlno, A. (1957) The chemistry, optics and genesisof the alkali amphiboles. -/. Foc. Sci. Unht. Tohyo Sec.II,11,57-83. Ross, M., J. J. Palrxn, erlo K. W. Snew (1969) Exsolution textures in amphiboles as indicatorsof subsolidusthermalhistories. Mi,neral.Soc.Amer.Spec.paper2,2T5-299. Sau-nua, Tu. G. (1956) optical anornalies in arfvedsonite from Greenland. Ama. Mineral,. 41, 509-512. Tavlon, H. P. erl R. G. Cor,ruelr (1968) Os/O16 ratios of coexisting minerals in glauco- phane bearing metamorphic rccks. Geol,.Soc. Amer. Butt,.79, 1727-1756..
Load more

Recommended publications
  • Glaucophane Na2[(Mg; Fe )3Al2]Si8o22(OH)2 C 2001 Mineral Data Publishing, Version 1.2 ° Crystal Data: Monoclinic
    2+ Glaucophane Na2[(Mg; Fe )3Al2]Si8O22(OH)2 c 2001 Mineral Data Publishing, version 1.2 ° Crystal Data: Monoclinic. Point Group: 2=m: As prismatic crystals; columnar, ¯brous, or granular aggregates; massive. Twinning: Simple or multiple twinning 100 . k f g Physical Properties: Cleavage: Perfect on 110 , intersecting at 56± and 124±; partings on 010 , 001 . Fracture: Conchoidalfto ugneven. Tenacity:»Brittle. H»ardness = 6 D(meas.) = f3.08{g3.f22 gD(calc.) = 3.132 Optical Properties: Translucent. Color: Gray, lavender-blue, commonly zoned; lavender-blue to colorless in thin section. Streak: Blue-gray. Luster: Vitreous to pearly. Optical Class: Biaxial ({). Pleochroism: Vivid; X = yellow to colorless; Y = violet to lavender; Z = blue. Orientation: Y = b; Z c = 7± to 6±, X a 8±. Dispersion: r < v; weak. ^ ¡ ¡ ^ ' ® = 1.594{1.630 ¯ = 1.612{1.648 ° = 1.619{1.652 2V(meas.) = 0±{50± Cell Data: Space Group: C2=m: a = 9.595 b = 17.798 c = 5.307 ¯ = 103:66± Z = 2 X-ray Powder Pattern: Sebastopol quadrangle, California, USA. (ICDD 20{453). 8.26 (100), 3.06 (65), 2.693 (60), 4.45 (25), 3.38 (25), 2.937 (25), 2.523 (25) Chemistry: (1) (2) (1) (2) (1) (2) SiO2 58.04 56.28 FeO 6.12 10.34 K2O 0.02 0.11 TiO2 0.66 0.17 MnO 0.07 0.25 F 0.02 Al2O3 10.31 12.16 MgO 11.71 8.41 Cl 0.01 + Fe2O3 2.89 1.72 CaO 1.37 0.62 H2O 1.98 Cr2O3 0.11 Na2O 6.97 7.04 H2O¡ 0.00 Total 100.17 97.21 (1) Tiburon Peninsula, California, USA; corresponds to (Na1:96Ca0:04)§=2:00(Mg2:39Al1:82 2+ 3+ Fe0:61Fe0:18)§=5:00Si8O22(OH)2: (2) Kodiak Islands, Alaska, USA; by electron microprobe, 2+ 3+ 2+ 3+ Fe :Fe calculated; corresponds to (Na1:90Ca0:09K0:02)§=2:01(Al1:82Mg1:74Fe1:20Fe0:18 Mn0:03Ti0:02Cr0:01)§=5:00(Si7:83Al0:17)§=8:00O22(OH)2: Polymorphism & Series: Forms a series with ferroglaucophane.
    [Show full text]
  • Riebeckite Na2[(Fe2+,Mg)3Fe 2 ]Si8o22(OH)
    2+ 3+ Riebeckite Na2[(Fe ; Mg)3Fe2 ]Si8O22(OH)2 c 2001 Mineral Data Publishing, version 1.2 ° Crystal Data: Monoclinic. Point Group: 2=m: As prismatic crystals, to 20 cm. Commonly ¯brous, asbestiform; earthy, massive. Twinning: Simple or multiple twinning 100 . k f g Physical Properties: Cleavage: Perfect on 110 , intersecting at 56 and 124 ; partings f g ± ± on 100 , 010 . Fracture: [Conchoidal to uneven.] Tenacity: Brittle. Hardness = 6 f g f g D(meas.) = 3.28{3.44 D(calc.) = 3.380 Optical Properties: Semitransparent. Color: Black, dark blue; dark blue to yellow-green in thin section. Luster: Vitreous to silky. Optical Class: Biaxial (+) or ({). Pleochroism: X = blue, indigo; Y = yellowish green, yellow- brown; Z = dark blue. Orientation: Y = b; X c = 8 to 7 ; Z c = 6 {7 . Dispersion: ^ ¡ ± ¡ ± ^ ± ± Strong. ® = 1.656{1.697 ¯ = 1.670{1.708 ° = 1.665{1.740 2V(meas.) = 50±{90±. Cell Data: Space Group: C2=m: a = 9.822 b = 18.07 c = 5.334 ¯ = 103:52± Z = 2 X-ray Powder Pattern: Doubrutscha [Dobrudja], Romania. (ICDD 19-1061). 8.40 (100), 3.12 (55), 2.726 (40), 2.801 (18), 4.51 (16), 2.176 (16), 3.27 (14) Chemistry: (1) (2) (1) (2) SiO2 52.90 50.45 CaO 0.12 0.08 TiO2 0.57 0.14 Li2O 0.54 Al2O3 0.12 1.96 Na2O 6.85 6.80 Fe2O3 17.20 17.52 K2O 0.03 1.48 Cr2O3 0.04 F 2.58 + FeO 17.95 17.90 H2O 0.87 MnO 0.00 1.40 O = F 1.09 ¡ 2 MgO 2.96 0.05 Total 98.74 100.68 (1) Dales Gorge Iron Formation, Western Australia; by electron microprobe, corresponds to 2+ 3+ (Na2:00Ca0:02K0:01)§=2:03(Fe2:26Mg0:66Ti0:06)§=2:98Fe1:95(Si7:98Al0:02)§=8:00O22(OH)2: (2) Pikes 2+ Peak area, Colorado, USA; corresponds to (Na2:02K0:29Ca0:01)§=2:32(Fe2:30Li0:33Mn0:18Al0:10 3+ Ti0:02Mg0:01)§=2:94Fe2:02(Si7:75Al0:25)§=8:00O22[F1:25(OH)0:89]§=2:14: Polymorphism & Series: Forms a series with magnesioriebeckite.
    [Show full text]
  • Geology and Age of the Lac a La Perdrix Fenite, Southern Gatineau District, Quebec
    CA9700383 -4- Geology and age of the Lac a la Perdrix fenite, southern Gatineau district, Quebec D.D. Hogarth1 and Otto van Breemen2 Hogarth, D.D. and van Breemen, 0., 1996: Geology and age of the Lac a la Perdrix fenite, southern Gatineau district, Quebec; inRadiogenic Age and Isotopic Studies: Report 9; Geological Survey of Canada, Current Research 1995-F, p. 33-41. Abstract: The Lac a la Perdrix fenite lies in the Central Metasedimentary Belt of the Grenville Province. This 30 m wide fenite, adjacent to a narrow calciocarbonatite sill, replaces diopside-oligoclase gneiss and is composed of magnesio-arfvedsonite, aegirine, microcline, albite, and fluorapatite. Near the contact with carbonatite, it contains appreciable monazite and barite whereas aegirine virtually disappears. Fenitization probably took place early in the igneous stage of carbonatite development. A Pb/U monazite age of 1026 ± 2 Ma is thought to date fenite formation. Together with published data, this age shows that carbonatite intruded metamorphic rocks near the close of the Grenville Orogeny. Resume : La fenite de Lac a la Perdrix s'observe dans la ceinture metasedimentaire de la Province de Grenville. Cette fenite, mesurant 30 m de largeur et en position adjacente par rapport a un etroit filon-couche de calciocarbonatite, remplace un gneiss a diopside-oligoclase et se compose de magnesio-arfvedsonite, d'aegirine, de microcline, d'albite et de fluorapatite. Pres du contact avec la carbonatite, la fenite contient de la monazite et de la barytine en quantite appreciable, tandis que l'aegirine disparait pratiquement. La fenitisation a probablement eu lieu au debut de l'episode igne durant lequel s'est form6 la carbonatite.
    [Show full text]
  • Author's Personal Copy
    Author's personal copy Tectonophysics 494 (2010) 201–210 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto Elasticity of glaucophane, seismic velocities and anisotropy of the subducted oceanic crust L. Bezacier a,⁎, B. Reynard a, J.D. Bass b, J. Wang b, D. Mainprice c a Université de Lyon, Laboratoire de Sciences de la Terre, CNRS, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France b Department of Geology, University of Illinois, Urbana, IL, 61801, USA c Géosciences Montpellier UMR CNRS 5343, Université Montpellier 2, 34095 Montpellier Cedex 05, France article info abstract Article history: Upon subduction, the oceanic crust transforms to blueschists and eclogites, with seismic properties that Received 8 March 2010 gradually become similar to those of the surrounding mantle. In order to evaluate the anisotropy of Received in revised form 30 July 2010 blueschists and glaucophane-bearing eclogites, the elastic constants of glaucophane single-crystal plates from Accepted 9 September 2010 the Sesia–Lanzo Zone (Aosta Valley, Western Alps) were measured using Brillouin spectroscopy at ambient Available online 17 September 2010 conditions. The mean P- and S-wave velocities are 7.8 and 4.6 km s−1 respectively, and the anisotropy is high Keywords: (38.1% (AVP) and 27.3% (AVS)). Glaucophane develops strong LPO, characterized by the [001]-axes Elasticity concentrated sub-parallel to the lineation, and the {110} poles concentrated sub-perpendicular to the Glaucophane foliation in both blueschist and eclogite rocks. The measured LPO is in good agreement with viscoplastic self- Epidote consistent numerical models.
    [Show full text]
  • Chemical Composition and Petrogenetic Implications of Eudialyte-Group Mineral in the Peralkaline Lovozero Complex, Kola Peninsula, Russia
    minerals Article Chemical Composition and Petrogenetic Implications of Eudialyte-Group Mineral in the Peralkaline Lovozero Complex, Kola Peninsula, Russia Lia Kogarko 1,* and Troels F. D. Nielsen 2 1 Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia 2 Geological Survey of Denmark and Greenland, 1350 Copenhagen, Denmark; [email protected] * Correspondence: [email protected] Received: 23 September 2020; Accepted: 16 November 2020; Published: 20 November 2020 Abstract: Lovozero complex, the world’s largest layered peralkaline intrusive complex hosts gigantic deposits of Zr-, Hf-, Nb-, LREE-, and HREE-rich Eudialyte Group of Mineral (EGM). The petrographic relations of EGM change with time and advancing crystallization up from Phase II (differentiated complex) to Phase III (eudialyte complex). EGM is anhedral interstitial in all of Phase II which indicates that EGM nucleated late relative to the main rock-forming and liquidus minerals of Phase II. Saturation in remaining bulk melt with components needed for nucleation of EGM was reached after the crystallization about 85 vol. % of the intrusion. Early euhedral and idiomorphic EGM of Phase III crystalized in a large convective volume of melt together with other liquidus minerals and was affected by layering processes and formation of EGM ore. Consequently, a prerequisite for the formation of the ore deposit is saturation of the alkaline bulk magma with EGM. It follows that the potential for EGM ores in Lovozero is restricted to the parts of the complex that hosts cumulus EGM. Phase II with only anhedral and interstitial EGM is not promising for this type of ore.
    [Show full text]
  • Li in Minerals from the Ilimaussaq Alkaline Intrusion, South Greenland
    Li in minerals from the Ilimaussaq alkaline intrusion, South Greenland J. C. BAILEY, H. BOHSE, R. GWOZDZ and J. ROSE-HANSEN Bailey, J.C., Bohse, H., Gwozdz, R. and Rose-Hansen, J. 1993. Li in minerals from the Ilfmaussaq alkaline intrusion, South Greenland. Bulletin of the Geological Society of Denmark, vol. 40, pp. 288-299. Copenhagen 1993-12-30. https://doi.org/10.37570/bgsd-1993-40-13 Li was analysed by instrumental neutron activation analysis and Cerenkov counting in 120 mineral samples (30 species) from the Ilfmaussaq alkaline intrusion, South Greenland. More than 0.23 wt.% Li (0.5 wt.% Li2O) is found in polylithionite, neptunite, riebeckite, Na-cookeite, ephesite, arfvedsonite, gerasimovskite and astro­ phyllite. Arfvedsonite (200-2500 ppm Li) carries the bulk of Li in most of the highly alkaline rocks. Li-Mg and Li-F relations indicate that the distribution of Li is con­ trolled by the structure of minerals, their absolute contents of Mg and F and the fractionation stage within the intrusion. Li is probably linked with Fin the fluid state and this linkage continues into crystallising phases where Li occupies sites which also accommodate Mg. Li/Mg and Li/F ratios of Ilfmaussaq rocks and minerals are higher than in equivalent materials from the Lovozero intrusion (Kola, Russia). The Li­ Mg-Fe2+ geochemical association at Ilfmaussaq (Fe2+>>Mg) and Lovozero (Fe2+>Mg) contrasts with the commercially important Li-rich but Mg-Fe2+-poor association found in certain granite pegmatites and greisenised granites. Bailey, J. C., Bohse, H., Gwozdz, R. & Rose-Hansen,- J. Division for Petrology, Geological Institute, v)ster Voldgade 10, DK-1350 Copenhagen K, Denmark.
    [Show full text]
  • Metamorphic Evolution of High-Pressure, Low-Temperature Mafic Rocks Near Kini on the Island of Syros, Greece
    Metamorphic evolution of high-pressure, low-temperature mafic rocks near Kini on the island of Syros, Greece Erica DiFilippo Department of Geology, Smith College, Clark Science Center, Northampton, MA 01063-0100 Faculty sponsor: John B. Brady, Smith College INTRODUCTION The island of Syros in the Greek Cyclades exposes Eocene high-pressure, low temperature metamorphic rocks including marbles, blueschists and pelitic schists (Ridley, 1981). It has been proposed that these units have experienced two major eclogite-blueschist facies metamorphic events, the first occurring at 470-520°C and 14-18 kb and the second not exceeding 460°C and 14 kb (Lister, 1996). At approximately 20-25 Ma, these units became regionally overprinted by a medium-pressure metamorphism (Schliestedt, 1987). A well exposed sequence of metamorphosed mafic and ultra-mafic rocks outcrops along a 2.5 km long coastal cliff near Kini on the western coast of Syros. This suite consists of segments of glaucophane schist, eclogite, omphacite-epidote rock, pelitic schist, and serpentinite with blackwall reaction zones separating the serpentinite from the other rock types. This study combines petrographic and chemical evidence in order to determine whether the difference in the units exposed at Kini is due to differing bulk compositions or to differing metamorphic grades. FIELD RELATIONS Lithologies change dramatically over the 2.5 km coastal cliff of Kini. There is no distinct gradational pattern to the rock units exposed. Beginning at the southern tip of the field area and working northward, the rock units are glaucophane schist, omphacite-zoisite rock, glaucophane schist, eclogite, serpentinite and blackwall reaction zones, glaucophane schist, a greenschist facies unit and pelitic schist.
    [Show full text]
  • New Minerals Approved Bythe Ima Commission on New
    NEW MINERALS APPROVED BY THE IMA COMMISSION ON NEW MINERALS AND MINERAL NAMES ALLABOGDANITE, (Fe,Ni)l Allabogdanite, a mineral dimorphous with barringerite, was discovered in the Onello iron meteorite (Ni-rich ataxite) found in 1997 in the alluvium of the Bol'shoy Dolguchan River, a tributary of the Onello River, Aldan River basin, South Yakutia (Republic of Sakha- Yakutia), Russia. The mineral occurs as light straw-yellow, with strong metallic luster, lamellar crystals up to 0.0 I x 0.1 x 0.4 rnrn, typically twinned, in plessite. Associated minerals are nickel phosphide, schreibersite, awaruite and graphite (Britvin e.a., 2002b). Name: in honour of Alia Nikolaevna BOG DAN OVA (1947-2004), Russian crys- tallographer, for her contribution to the study of new minerals; Geological Institute of Kola Science Center of Russian Academy of Sciences, Apatity. fMA No.: 2000-038. TS: PU 1/18632. ALLOCHALCOSELITE, Cu+Cu~+PbOZ(Se03)P5 Allochalcoselite was found in the fumarole products of the Second cinder cone, Northern Breakthrought of the Tolbachik Main Fracture Eruption (1975-1976), Tolbachik Volcano, Kamchatka, Russia. It occurs as transparent dark brown pris- matic crystals up to 0.1 mm long. Associated minerals are cotunnite, sofiite, ilin- skite, georgbokiite and burn site (Vergasova e.a., 2005). Name: for the chemical composition: presence of selenium and different oxidation states of copper, from the Greek aA.Ao~(different) and xaAxo~ (copper). fMA No.: 2004-025. TS: no reliable information. ALSAKHAROVITE-Zn, NaSrKZn(Ti,Nb)JSi401ZJz(0,OH)4·7HzO photo 1 Labuntsovite group Alsakharovite-Zn was discovered in the Pegmatite #45, Lepkhe-Nel'm MI.
    [Show full text]
  • Optical Properties of Common Rock-Forming Minerals
    AppendixA __________ Optical Properties of Common Rock-Forming Minerals 325 Optical Properties of Common Rock-Forming Minerals J. B. Lyons, S. A. Morse, and R. E. Stoiber Distinguishing Characteristics Chemical XI. System and Indices Birefringence "Characteristically parallel, but Mineral Composition Best Cleavage Sign,2V and Relief and Color see Fig. 13-3. A. High Positive Relief Zircon ZrSiO. Tet. (+) 111=1.940 High biref. Small euhedral grains show (.055) parallel" extinction; may cause pleochroic haloes if enclosed in other minerals Sphene CaTiSiOs Mon. (110) (+) 30-50 13=1.895 High biref. Wedge-shaped grains; may (Titanite) to 1.935 (0.108-.135) show (110) cleavage or (100) Often or (221) parting; ZI\c=51 0; brownish in very high relief; r>v extreme. color CtJI\) 0) Gamet AsB2(SiO.la where Iso. High Grandite often Very pale pink commonest A = R2+ and B = RS + 1.7-1.9 weakly color; inclusions common. birefracting. Indices vary widely with composition. Crystals often euhedraL Uvarovite green, very rare. Staurolite H2FeAI.Si2O'2 Orth. (010) (+) 2V = 87 13=1.750 Low biref. Pleochroic colorless to golden (approximately) (.012) yellow; one good cleavage; twins cruciform or oblique; metamorphic. Olivine Series Mg2SiO. Orth. (+) 2V=85 13=1.651 High biref. Colorless (Fo) to yellow or pale to to (.035) brown (Fa); high relief. Fe2SiO. Orth. (-) 2V=47 13=1.865 High biref. Shagreen (mottled) surface; (.051) often cracked and altered to %II - serpentine. Poor (010) and (100) cleavages. Extinction par- ~ ~ alleL" l~4~ Tourmaline Na(Mg,Fe,Mn,Li,Alk Hex. (-) 111=1.636 Mod. biref.
    [Show full text]
  • Mineralogicai, Radiographic and Uranium Leaching Studies on the Uranium Ore from Kvanefjeld, Ilimaussaq Complex, South Greenland
    T><2too/t6' Risø-R-416 Mineralogicai, Radiographic and Uranium Leaching Studies on the Uranium Ore from Kvanefjeld, Ilimaussaq Complex, South Greenland Milota Makovicky, Emil Makovicky, Bjarne Leth Nielsen, Svend Karup-Møller, and Emil Sørensen Risø National Laboratory, DK-4000 Roskilde, Denmark June 1980 RISØ-R-416 MINERALOGICAL, RADIOGRAPHIC AND URANIUM LEACHING STUDIES ON THE URANIUM ORE FROM KVANEFJELD, ILIMAUSSAQ. COMPLEX, 'SOUTH GREENLAND Milota Makovickyl , Emil Makovicky2, Bjarne Leth Nielsen-! , Sven Karuo-Møller^ and Emil Sørensen^ Abstract. 102 samples of low-grade uranium ore from 70 drill holes at Kvanefjeld, Ilimaussaq alkaline intrusion, South Green­ land were studied by means of autoradiography, fission-track investigations, microscopy, microprobe analyses and uranium- leaching experiments. The principal U-Th bearing mineral, steen- strupine, and several less common uranium minerals are dis­ seminated in lujavrite 'nepheline syenite) and altered volcanic rocks. Stenstrupine has a/erage composition Na6.7HxCai.n e Al (REE+Y)5.8(Th,l')o.5 ( ""1 . 6*" 1 . S^Q. 3^0. l 0. 2 ) Sii2036 (P4.3Si-) ,7 )024 (F,OH). nH20; n and x are variable. It either is of magmatic origin (type A) or connected with metasomatic processes (type B), or occurs in late veins (Type C). Preponder­ ance of grains are metamict (usually 2000-5000 ppm U3O8) or al­ tered (usually above 5000 ppm U3O8), sometimes zoned with both (continue on next page) June 1980 Pisø National Laboratory, DK-4000 Roskilde, Denmark components present. Occasionally they are extremely altered with U content falling to 500-5000 ppm U3O8 and local accumulations of high-U minerals formed.
    [Show full text]
  • Kimberlites H3 RICHTERITE-ARFVEDSONITE
    Kimberlites References SVISERO, D.P.; Meyer, H.O.A. and Tsai, H.M. (1977) : FRAGOMENI, P.R.Z. (1976) : Tectonic control of Parana- Kimberlite minerals from Vargem ( Minas Gerais) tinga Kimberlitic Province, Boletim Nucleo and Redondao (Piaui) diatremes, and garnet Centro-Oeste Soc. Bras. Geol., 5,3-10. Iherzolite xenolith from Redondao diatreme. Goiania (in Portuguese). Revista Brasileira de Geociencias, 7, 1-13. SVISERO, D.P.; Haralayi, N.L.E. and Girardi, V.A.V. Sao Paulo. (1980) : Geology of Limeira 1, Limeira 2 and SVISERO, D.P.; Meyer, H.O.A, and Tsai, H.M. (1979b) : Indaia Kimberlites. Anais 31. Congresso Bra- Kimberlites in Brazil : An Initial Report. sileiro de Geologia, 3, 1789-1801. Camboriu, Proc. Second Intern. Kimberlite Conference, (in Portuguese). 1, 92-100. Amer. Geoph. Union, Washington. SVISERO, D.P.; Hasui, Y. and Drumond, D. (1979a) : Geo¬ logy of Kimberlites from Alto Paranaiba, Minas Gerais. Mineragao e Metalurgia, 42, 34-38. Rio de Janeiro ( in Portuguese). “ Research supported by Fapesp, CNPq and FINEP. H3 RICHTERITE-ARFVEDSONITE-RIEBECKITE-ACTINOLITE ASSEMBLAGE FROM MARID DIKES ASSOCIATED WITH ULTRAPOTASSIC MAGMATIC ACTIVITY IN CENTRAL WEST GREENLAND Peter THY f ^ Nordic Volcanological Institute University of Iceland, 101 Reykjavik, Iceland. Present address: Programs in Geosciences, The University of Texas at Dallas, P.O. Box 688, Richardson, Texas 75080 U.S.A. Introduction Crystal chemistry of the alkali amphiboles Dawson & Smith (1977) proposed that a mica- The amphibole chemistry is calculated according to amphibole-rutile-ilmenite-diopside (MARID) suite of the general formula AQ_jB2C5^Tg'^022(OH)2* Estimation xenoliths in kimberlites were cumulates from a highly of Fe3+ shows the main part of the amphiboles to con¬ oxidized kimberlitic magma in the upper part of the tain excess cations for charge balance.
    [Show full text]
  • List of Abbreviations
    List of Abbreviations Ab albite Cbz chabazite Fa fayalite Acm acmite Cc chalcocite Fac ferroactinolite Act actinolite Ccl chrysocolla Fcp ferrocarpholite Adr andradite Ccn cancrinite Fed ferroedenite Agt aegirine-augite Ccp chalcopyrite Flt fluorite Ak akermanite Cel celadonite Fo forsterite Alm almandine Cen clinoenstatite Fpa ferropargasite Aln allanite Cfs clinoferrosilite Fs ferrosilite ( ortho) Als aluminosilicate Chl chlorite Fst fassite Am amphibole Chn chondrodite Fts ferrotscher- An anorthite Chr chromite makite And andalusite Chu clinohumite Gbs gibbsite Anh anhydrite Cld chloritoid Ged gedrite Ank ankerite Cls celestite Gh gehlenite Anl analcite Cp carpholite Gln glaucophane Ann annite Cpx Ca clinopyroxene Glt glauconite Ant anatase Crd cordierite Gn galena Ap apatite ern carnegieite Gp gypsum Apo apophyllite Crn corundum Gr graphite Apy arsenopyrite Crs cristroballite Grs grossular Arf arfvedsonite Cs coesite Grt garnet Arg aragonite Cst cassiterite Gru grunerite Atg antigorite Ctl chrysotile Gt goethite Ath anthophyllite Cum cummingtonite Hbl hornblende Aug augite Cv covellite He hercynite Ax axinite Czo clinozoisite Hd hedenbergite Bhm boehmite Dg diginite Hem hematite Bn bornite Di diopside Hl halite Brc brucite Dia diamond Hs hastingsite Brk brookite Dol dolomite Hu humite Brl beryl Drv dravite Hul heulandite Brt barite Dsp diaspore Hyn haiiyne Bst bustamite Eck eckermannite Ill illite Bt biotite Ed edenite Ilm ilmenite Cal calcite Elb elbaite Jd jadeite Cam Ca clinoamphi- En enstatite ( ortho) Jh johannsenite bole Ep epidote
    [Show full text]