 | | Journal (article/letter/editorial) | | lattice dimensionsof (Ba,K,Na)-feldsparsfrom Otjosondu,Namibia and their significance KnrsnNeuooRTHy VrsweNernAN...twenty samplesof (Ba,K,Na)-feldsparsfrom Otjosondu, Namibia reveal that they can be divided into the...Al2Si2Os)-poor,Ab-rich ones containing unmixed albite phases (2) Cn-rich varieties showing occasionalunmixed...(Viswanathan,1978)in a few specimensfrom Otjosondu, Namibia, suggestthat the barium feldspars are probablyso...compositionand structuralstateof (Ba,K,Na)-feldspars from Otjosondu in order to determine their effect on the lattice |  | B HN, B., OKRUSCH, M., WOERMANN, E., LEHNERT, K., HOERNES, S. (1995) Metamorphic Evolution of Neoproterozoic Manganese Formations and their Country Rocks at Otjosondu, Namibia. Journal of Petrology, 36 (2) 463-496 doi:10.1093/petrology/36.2.463 | Journal (article/letter/editorial) | | depending on their paragenesis. They indicate very Namibia were subjected to high-^T-low-P metamorphism dur-...WORD& manganiferous sediments; Damara Orogeny; Namibia; formations. They are correlated with peak pressure...Manganese Formations and their Country Rocks at Otjosondu, Namibia JOURNAL OF PETROLOGY VOLUME :t(i NUMBER...and Miller (1983a) tentatively correlated the Otjosondu ores with the Chuos Formation, which bears glaciomarine...metallogenetic model (Buhn et al., 1992, 1993*). The Otjosondu Mn ore-bearing unit consists of at least two manganese |  | | Journal (article/letter/editorial) | | Institute of Mineralogy, Miass, 456317, Chelyabinsk Region, Russia ABSTRACT An unusual garnet representing...metasedimentary rocks in India (Katkamsandi, Netra), Namibia (Otjosondu, Gamsberg, Namaqualend), Greece (Andros Island)...Lake Bolshoe Miassovo (Ilmeny Reserve, Chelyabinsk region, Russia) (Fig. 1) in a NS-trending band of blastomylonites...the Ilmeny Mountains (Ilmeny Reserve, Chelyabinsk region, Russia). Asterisk, location of pit 287. FIG....magnesio-hornblende (near 1%), and rare microcline, albite, zircon, titanite, garnet, and allanite; small |  | Essene, Eric J., Claflin, Christopher L., Giorgetti, Giovanna, Mata, Pilar M., Peacor, Donald R., Á rkai, Pé ter, Rathmell, Mark A. (2005) Two-, three- and four-feldspar assemblages with hyalophane and celsian: implications for phase equilibria in BaAl2Si2O8-CaAl2Si2O8-NaAlSi3O8-KAlSi3O8. European Journal of Mineralogy, 17 (4) 515-535 doi:10.1127/0935-1221/2005/0017-0515 | Journal (article/letter/editorial) | | BaAl2Si2O8–CaAl2Si2O8–NaAlSi3O8–KAlSi3O8. Hyalophane occurs with albite and microcline in a very low grade (anchizonal...little Ba in albite and only limited Na in hyalophane. One marble from the garnet zone has albite (Ab95-98)...(Cn65Sl3An2Ab9Or24) and celsian (Cn92Sl3An1Ab2Or2). The albite and oligoclase are complexly intergrown and may...cooling. A marble in the sillimanite zone contains albite (Ab95-98Or2-3), oligoclase (An17An2Sl3Ab33Or24)...inclusion of celsian (Cn67An1Sl2Ab2Or91) in an albite. Sanidine from the Peshtigo monzonite in Wisconsin |  | | Journal (issue) | | ........................pg. 3 Actinolite from Namibia by Justin Zzyzx .................................we bring you eleven articles about locations in Namibia that do not receive much publicity. It is easy...legendary deposits such as Tsumeb, the Brandberg region and the Erongo Mountains. Alpine clefts, huge soda...Mountains, located in the southwestern part of central Namibia. The Gamsberg Mountain is the most important landmark...Fluorapatite Fluorapatite is quite rare from the region but can be found as complex, colorless crystals |  | CABRAL, A. R., MOORE, J. M., MAPANI, B. S., KOUBOVA, M., SATTLER, C.- D. (2011) GEOCHEMICAL AND MINERALOGICAL CONSTRAINTS ON THE GENESIS OF THE OTJOSONDU FERROMANGANESE DEPOSIT, NAMIBIA: HYDROTHERMAL EXHALATIVE VERSUS HYDROGENETIC (INCLUDING SNOWBALL-EARTH) ORIGINS. South African Journal of Geology, 114 (1) 57-76 doi:10.2113/gssajg.114.1.57 | Journal (article/letter/editorial) | | CONSTRAINTS ON THE GENESIS OF THE OTJOSONDU FERROMANGANESE DEPOSIT, NAMIBIA: HYDROTHERMAL EXHALATIVE VERSUS...Department of Geology, University of Namibia, Private Bag 13301, Windhoek, Namibia e-mail: b.mapani@unam.na M...Africa ABSTRACT The stratigraphic position of the Otjosondu ferromanganese deposit in the Neoproterozoic Damara...the Swakop Group, as previously proposed. The Otjosondu ore comprises ferromanganese silicate-oxide assemblages...and manganese formations. The formation of the Otjosondu ferromanganese deposit is therefore unrelated |  | | Journal (article/letter/editorial) | | highly metamorphosed manganeseore deposit of Otjosondu, Namibia, contain two interesting types: (l) barium-rich...typical feature of most barium feldsparsfrom Otjosondu is that the cleavages,including (001), are usually...of this crystal confirmed the absenceof unmixed albite, though thin sections of bigger crystalsshowedoccasionalalbite...specimens were homogeneous except for occasional albite lamellae. The calculated formula is (Bao,nKorrNao12)...grotp A/m). + : Natural barium feldspars from Otjosondu, Namibia; O : Na/K exchanged barium feldspar (Ba + |  | | Book | | Mountainland The Central Northern to Northwest Region including Damaraland The Central Namib Desertand...Copper Deposits The South The Pegmatitesin Central Namibia Luderitz and the Diamonds 44 49 241 254 272 275... Encyclopedia of the Mineralsof Namibia 443 Meteorites in Namibia Bibliography Index Photo credits...__ Republic of Namibia The President State House W°Ntdhoek FOREWORD Namibia is endowed with an...from near and far. Fine mineral specimen from Namibia are displayed in all the famous natural science |  | | Journal (article/letter/editorial) | | stability of both minerals is constrained in the region of low f CO2 . The paper reports data on the Fe–Si–O...First, Fig. 1 shows two subparallel lines in the region of high oxygen fugacity corresponding to the reactions...reactions (1), (8), and (5) and encompasses the region of log f O2 values at which braunite is stable...diagram, below the reaction lines 7 and 6. This region of relatively low log f O2 values corresponds to...previous diagram (Fig. 1), it corresponds to the region in the vicinity of reaction line 4. Because of |  | | Journal (article/letter/editorial) | | A NEW OCCURRENCE OF BARIUM-FELDSPAR AT OTJOSONDU, SOUTH-WEST AFRICA, AND AN THE X-RAY METHOD FOR DETERMINING...INrnolucrroN In a study of the manganeseores of Otjosondu, South-West Africa, de Villiers (1, p. 95) describedtwo...Molecular composition Celsian (Cn) Orthoclase (Or) Albite (Ab) Anorthite (An) Total 94.49 3.06 1.05 0.61...0471 0.1223 0.0254 Celsian (Cn) Orthoclase (Or) Albite (Ab) Nepheline (Ne) Total 9 .5 1 6 8 .1 5 18.28...Molecular composition Celsian(Cn) Orthoclase(Or) Albite (Ab) Anorthite (An) Nepheline(Ne) Total 37.28 |  | | Journal (article/letter/editorial) | | Ca–Mn–Al–Fe3þ quadrilateral. 1: Amphibolite-facies, Namibia (Vermaas, 1952; Dunn, 1979). 2: Amphibolite facies...grossular-almandine garnet in gneiss with quartz, microcline, albite, biotite, epidote, hematite, titanite and zircon)...Mn–Zn-spinel, quartz. 12. Amphibolite facies, Otjosondu, Namibia (B€uhn et al., 1995), with braunite, jacobsite...standards: diopside (Si, Mg, Ca), anorthite (Al), albite (Na), orthoclase (K), Fe2O3, MnTiO3 (Mn, Ti), AsGa...-bearing calderite-andradite garnets from Otjosondu, SWA=Namibia. Zeit Krist 189: 43–56 Andrut M, Wildner |  | | Journal (article/letter/editorial) | | source of Ti for Ti-rich jadeitite. Quartz and albite have not been found in the studied sample. Pectolite...Ab1ÿ3An0ÿ1. There is no apparent change in the albite content of feldspars (1ÿ3% Ab) over this compositional...from Shaba, ZaõÈre (Chabu and BouleÁgue, 1992) and albite-mica rocks from the Motagua Valley, Guatemala (Harlow...constrain the pressure below the jadeite + quartz = albite reaction and above jadeite + H2O = analcime, i...fractionation of Ab (albite), Or (orthoclase) and Cn (celsian). (a) This study, and mica-albite rocks which occurred |  | | Journal (article/letter/editorial) | | manganese deposits or manganiferous iron ores of Otjosondu, Namibia (Viswanathan and Kielhoru, 1983), Benallt...is no significant anorthite component, and the albite component is relatively constant at between 3 and...and Griffin (1973) have shown that in the Oslo region of Norway, hyalophane is pseudomorphic after baryte...(1973) Barium feldspar in Ordovician sediments, Oslo region, Norway. J. Sediment. Petrol., 43, 461-5. Bostrrm...Morey, G. B. (1983a) Animikie basin, Lake Superior region, U.S.A., In Iron-formation facts and problems (A |  | | Journal (article/letter/editorial) | | Ba-rich and Ba-poor phases in barium feldspars from Otjosondu, South-West Africa BARIUM feldspars have been...associated with the metamorphosed manganese ores in Otjosondu, SouthWest Africa (Vermaas, I953). The crystals...angle is least influenced by the presence of the albite component. Precession photographs show that the |  | | Journal (article/letter/editorial) | | emeleusite, riebeckite, nordite, aegifine, narsarsukite, albite, 3I Klokken, Gardar, feldspars, syenite, aplite...tlapallite, 183 South-West Africa (Namibia) Onganja mine, cuprite, 5o5 Otjosondu, celsian, barian orthoclase |  | | Book | | REPUBLIC OF NAMIBIA - MINISTRY OF MINES AND ENERGY GEOLOGICAL SURVEY THE MINERAL RESOURCES OF NAMIBIA FIRST...ENERGY Of the several hundred minerals present in Namibia, around sixty have been exploited. some, such as...base metals and industrial minerals have helped Namibia rank amongst the top five mining countries in Africa...terms of production and reserves. In this context, Namibia is a major producer of copper, lead, zinc, cadmium...unpublished. It is evident that mineral exploration in Namibia, as elsewhere. has changed from serendipitous discoveries |  | | Journal (article/letter/editorial) | | Cn-poor feldhomogeneousand not to contain any unmixed albite (Viswanathanand Brandt, 1980)are included spar...lattice dimensions of (Ba,K,Na)feldspars from Otjosondu, Namibia and their significance. American Mineralogist |  | | Journal (article/letter/editorial) | | bestknown worldwide localities include the Tyrol region, Austria; the Stikine River delta, near Wrangell...deposits or manganese-bearing rocks, such as Otjosondu, Namibia (Amthauer et al. 1989), and Andros Island...rocks, including the Otjosundu manganese mine, Namibia. Calderite also exhibits solid solution toward...Carolina; others include Ceylon; the Umba Valley region, Tanzania and Kenya; Zimbabwe; Madagascar; and...spessartine, was discovered in the Umba River Valley region of Tanzania in the mid-1960s. The name (also spelled |  | | Journal (article/letter/editorial) | | the so-called celsianwith Cn 50 and Cn 55 from Otjosondu, South West Africa (Vermaas. 1953) and to a so-calledcelsianwith...skarn silicates,notably in the olivine hancockite. Albite and anorthite have been identified at Franklin...skarn zones.A mineral tentatively identified as albite with anomalousfeatures was mentioned by Larsen |  | | Journal (article/letter/editorial) | | Manickvasagam, 1981; Bhattacharya et al., 1984) and Namibia (B uhn et al., 1995), where it was observed that...The following compounds were used as standards: albite, orthoclase, periclase, wollastonite and synthetic...quartz albite b: Ti±braunite hematite spessartine piemontite a: Hematite quartz albite b: Ti±braunite...piemontite a: Hematite ilmenite rutile quartz albite aegirine riebeckite phlogopite b: Ti±braunite...have a porphyritic texture with phenocrysts of albite and quartz in a microcrystalline siliceous matrix |  | | Journal (article/letter/editorial) | | accelerating voltage was 15-20 kV, and natural sanidine, albite, celestine and baryte were used as standards. These...et al. (1984). The transition from the triclinic albite structure to the monoclinic celsian structure takes...Catel (1992) observed immiscibility only near the albite end-member. The coexisting feldspar phases were...extent of solid solution - - a relatively wide region of solid solution near celsian and a narrow range...included in Table 5. For (Na,K)-feldspar (high albite-sanidine) we calculated W1 and W2 parameters based |  | | Journal (article/letter/editorial) | | the Postdepositedby hypogenesolutions. masburg region and is a major constituentof the Kalahari ores...present Namibia (25.59%Fe•Os) found that at 100øC manganiteand cryptomelane in braunitefrom Otjosondu, form...with dull, cryptocrystallineperoxamesite,apatite,albite,acmite,and gamagarite(J.E. idesandpartridgeite...indicated,and this suchlocalities asOtjosondu, Namibia(J.E. de Villiers, zoningwould be superimposed on...localitieswhere the temperature and consist of albite(Ab95-1oo) lathswith alteredfer- was low. Apart |  | | Journal (article/letter/editorial) | | (India) West-Tirodi, Madhya Pradesh (India) Otjosondu (Namibia) Wabush Dr., Labrador Trough (Canada) 69...along the Southern margin of the Damara Orogen/Namibia (SW-Africa). Geol Rundsch 67:719-742 Akimoto SI...Hill, New York Holland TJB (1980) The reaction albite=jadeite+quartz determined experimentally in the...London Roper H (1956) The manganese deposits at Otjosondu, South West Africa. In: Gonzales Reyna J (ed)...Vermaas FHS (1952) Manganese-iron garnet from Otjosondu, South-West Africa. Mineral Mag 29:946-951 Virgo |  | | Journal (article/letter/editorial) | | sheeted leucogranites within the Damara Orogen, Namibia J. A. Kinnaird* and P. A. M. Nex Uranium mineralisation...southern Central Zone of the Damara Orogen in Namibia; at Rössing, Valencia, the Ida Dome and Goanikontes...Formation boundary. Keywords: Granite, Mineralisation, Namibia, Uranium Since 2004, the development of new nuclear...exploration and particularly in southern Africa. Namibia constitutes a uraniferous province with known uranium...in sheeted leucogranites within Damara Orogen, Namibia 1 The inland branch of the Damara Orogen showing |  | Dasgupta, Somnath, Sengupta, Pulak, Bhattacharya, P. K., Mukherjee, M., Fukuoka, M., Banerjee, H., Roy, Supriya (1989) Mineral reactions in manganese oxide rocks; P-T-X phase relations. Economic Geology, 84 (2) 434-443 doi:10.2113/gsecongeo.84.2.434 | Journal (article/letter/editorial) | | zone,660øC,6 kbars + Hs + Qz Urandi, Brazil Otjosondu, (iv) Br01q-Py q-Qz Chloritezone (v) Br0y q-Jbq-Hm...6 kbars Bhattacharya et al. (1984) Lawsonite-albite facies Huebner (1967) 420 ø q- 30øC, 3 kbars...de Villiers (1983) Bhattacharyaet al. (1988) Namibia India California, (ix) Br + Rdh q-Hs ___ Qz |
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