 | | Report (chapter) | | have resulted from later regional mapping by the Tanzania Geological Survey, together with radiometric dating...Extrusive basaltic centres. The term ‘peralkaline volcano’ is used here to indicate that the structure is...(unpublished) state that the oldest lavas from this volcano are melanephelinites and melilitites of the Bast...Bast Hills and Birera, to the west of the main volcano. These, as with early lavas from some other centres...Ngorongoro, Oldeani, Gelai, Ketumbeine, Tarosero, Monduli and the Shira and Mawenzi centres of Kilimanjaro) |  | | Journal (article/letter/editorial) | | Lengai, Tanzania Kerimasi, Tanzania Sadiman, Tanzania Arusha-Monduli, Tanzania Hanang, Tanzania Kwahera...Kwahera, Tanzania Basotu tuff cones, Tanzania Kaluwe, Zambia Mwambuto, Zambia Chasweta, Zambia Gross Brukkaros...Chagatai, Uzbekistan Polino, Italy Natron-Engaruka, Tanzania Laacher See, Germany R R R R R R R R R R R R...intrusive carbonatites. Although the Oldoinyo Lengai volcano and its pristine natrocarbonatite lavas is well...crystal aggregates of calcite as being after nyerereite, a ubiq- uitous phase in the recent Oldoinyo |  | | Journal (article/letter/editorial) | | OF MINERALS Nyerereite from Calcite Carbonatite at the Kerimasi Volcano, Northern Tanzania A. N. Zaitsev...Quaternary Kerimasi volcano located in the southern part of the Gregory Rift, north ern Tanzania, contains...spectroscopy and SEM/EDS, this mineral was identified as nyerereite, ideally Na2Ca(CO3)2. It occurs as solid inclusions...latestage, subsolidus mineral. The occurrence of nyerereite in carbonatite supports Hay’s (1983) idea that...at the Kerimasi volcano were originally alkaline rich and contained both calcite and nyerereite as primary |  | | Journal (article/letter/editorial) | | East African rift system in Kenya, Uganda, and Tanzania. Although some of these were studied by earlier...and pyroclastics of the Djombo, OldoinyoL'Engai, Kerimasi, Hanang, Kwaraha, Lashaine, Toror, and Kazekere...area; the Kavirondo ridge; and the Natron-Engaruka region. The rock samples studied were collected by V....Oldoinyo-L'Engai and Nyamlagira Fort Portal and Bunyaguru Kerimasi Kwaraha, Meru, and Hanang Elgon and Kadam Bukusu... The eroded cinder cone of the gigantic Elgon Volcano is as much as 85 km in diameter and 3.5 km in height |  | | Report (chapter) | | Uganda; Songhor and Koru, Kenya; and Laetoli, Tanzania. Some, and perhaps most, of the carbonatite ash...eruptions were from O1 Doinyo Lengai, in northern Tanzania (Fig. 1), which has discharged both lavas and..."~"'",~ Tanzania . 2o - .x" ~ . . Oldoinyo Lengai Olduvai G o r g e * ~ '~-~ Kerimasi Laetoli...premodern carbonatite volcanic rocks of Kerimasi volcano in Tanzania (Hay 1983) and the Tinderet centre in...carbonatires originally consisted of nyerereite with subordinate calcite. Nyerereite reacts incongruently with water |  | | Journal (article/letter/editorial) | | April 2013, Vol. 77(3), pp. 213–226 Tinderet volcano, Kenya: an altered natrocarbonatite locality? A...Editor: Ray Macdonald] ABSTRACT The Tinderet volcano (19.9 to 5.5 Ma), located within the Kavirondo...accessory perovskite and ‘plumbopyrochlore’; nyerereite is present as inclusions in the perovskite. At...natrocarbonatites from the Oldoinyo Lengai and Kerimasi volcanoes that have altered and recrystallized...originally alkali-rich rocks which contained primary nyerereite. K EY WORDS : carbonatite, natrocarbonatite, |  | | Journal (article/letter/editorial) | | kimberlite liquids Nyerereite and shortite were found within the melt inclusions. D Nyerereite and shortite...come from a crustal AC source. Orthorhombic nyerereite (Na,K)2Ca(CO3)2 and shortite were identified...temperature is as high as 500 оС. Generally, MI nyerereite is considered as a magmatic mineral but experiments...about 300 оС indicating that LT orthorhombic nyerereite may crystallise directly from the melt as well...carbonatite, melt inclusion, alkaline carbonate, nyerereite, SC R IP shortite, Raman spectroscopy. 1 |  | Campeny, Marc, Kamenetsky, Vadim S., Melgarejo, Joan C., Mangas, José, Manuel, José, Alfonso, Pura, Kamenetsky, Maya B., Bambi, Aurora C.J.M., Gonçalves, Antonio O. (2015) Carbonatitic lavas in Catanda (Kwanza Sul, Angola): Mineralogical and geochemical constraints on the parental melt. Lithos, 232. 1-11 doi:10.1016/j.lithos.2015.06.016 | Journal (article/letter/editorial) | | carbonatite lavas have been identified in this region and considering the mineralogical, textural and...presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for...natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our ACCEPTED MANUSCRIPT conclusion...1984; Zaitsev et al., 2013) or Kerimasi and Oldoinyo Lengai in Tanzania (Hay, 1983; Church, 1996; Guzmics...Oldoinyo Lengai is the only active carbonatite volcano known, and ACCEPTED MANUSCRIPT where unique natrocarbonatite |  | Zaitsev, A. N., Williams, C. T., Britvin, S. N., Kuznetsova, I. V., Spratt, J., Petrov, S. V., Keller, J. (2010) Kerimasite, Ca3Zr2(Fe23+Si)O12, a new garnet from carbonatites of Kerimasi volcano and surrounding explosion craters, northern Tanzania. Mineralogical Magazine, 74 (5) 803-820 doi:10.1180/minmag.2010.074.5.803 | Journal (article/letter/editorial) | | carbonatites of Kerimasi volcano and surrounding explosion craters, northern Tanzania A. N. ZAITSEV1,2...extinct nephelinitic volcano Kerimasi and surrounding explosion craters in northern Tanzania. The mineral occurs...The name is given after the locality, Kerimasi volcano, Tanzania. K EY WORDS : kerimasite, kimzeyite...composition, crystal structure, Kerimasi, Loluni, Kisete, Loolmurwak, Tanzania. * E-mail: burbankite@gmail...et al., 1994), Oldoinyo Lengai, Gregory rift, Tanzania (Dawson et al., 1995; Dawson and Hill, 1998), |  | Guzmics, Tibor, Mitchell, Roger H., Szabó, Csaba, Berkesi, Márta, Milke, Ralf, Abart, Rainer (2011) Carbonatite melt inclusions in coexisting magnetite, apatite and monticellite in Kerimasi calciocarbonatite, Tanzania: melt evolution and petrogenesis. Contributions to Mineralogy and Petrology, 161 (2) 177-196 doi:10.1007/s00410-010-0525-z | Journal (article/letter/editorial) | | magnetite, apatite and monticellite in Kerimasi calciocarbonatite, Tanzania: melt evolution and petrogenesis...29 April 2010 Ó Springer-Verlag 2010 Abstract Kerimasi calciocarbonatite consists principally of calcite...Calciocarbonatite Peralkaline silicate melt Kerimasi Tanzania Electronic supplementary material The online...minerals occurring in calciocarbonatite from Kerimasi volcano (Tanzania). These rocks consist principally of...natrocarbonatites. Kerimasi is a stratovolcano located in the Gregory Rift Valley, Northern Tanzania (2°510 S; |  | | Journal (article/letter/editorial) | | (2006) CALCIOCARBONATITE DYKES AT OLDOINYO LENGAI, TANZANIA: THE FATE OF NATROCARBONATITE Jörg KELLER§ Institut...from the active natrocarbonatite volcano Oldoinyo Lengai, Tanzania. The dykes are fine grained, with...polycrystalline nature of calcite pseudomorphs after nyerereite. Noteworthy in the secondary calcite are the...mineralogy, chemical balance, stable isotopes, Tanzania. Sommaire Nous décrivons pour la première fois...valley, is the world’s only active carbonatite volcano and is well known for the unusually alkali-rich |  | Zaitsev, A. N., Keller, J., Spratt, J., Perova, E. N., Kearsley, A. (2008) NYEREREITE - PIRSSONITE - CALCITE - SHORTITE RELATIONSHIPS IN ALTERED NATROCARBONATITES, OLDOINYO LENGAI, TANZANIA. The Canadian Mineralogist, 46 (4) 843-860 doi:10.3749/canmin.46.4.843 | Journal (article/letter/editorial) | | 843-860 (2008) DOI : 10.3749/canmin.46.4.843 NYEREREITE – PIRSSONITE – CALCITE – SHORTITE RELATIONSHIPS...IN ALTERED NATROCARBONATITES, OLDOINYO LENGAI, TANZANIA Anatoly N. ZAITSEV§ Department of Mineralogy,...1917 explosive eruption at Oldoinyo Lengai volcano, in Tanzania. The carbonatite samples contain two mineral...consists of relict primary magmatic minerals: nyerereite, fluorite, apatite-(CaF), barite, magnetite and...minerals show the following sequence of formation: nyerereite ! pirssonite ! calcite ! shortite. Three major |  | | Journal (article/letter/editorial) | | forsterite–phlogopite ijolites at Oldoinyo Lengai Volcano, Tanzania: study of melt inclusions V.S. Sekisova a...minerals of ijolite xenoliths at Oldoinyo Lengai Volcano. Melt inclusions with different phase compositions...a fine-grained aggregate of Na–Ca-carbonates (nyerereite and gregoryite). Fluorapatite contains primary...melt inclusions in the core, which consist of nyerereite, gregoryite, thenardite, witherite, fluorite...inclusions; silicate–carbonate immiscibility; ijolite; nyerereite; natrocarbonatite; Oldoinyo Lengai Introduction |  | Káldos, Réka, Guzmics, Tibor, Mitchell, Roger H., Dawson, John Barry, Milke, Ralf, Szabó, Csaba (2015) A melt evolution model for Kerimasi volcano, Tanzania: Evidence from carbonate melt inclusions in jacupirangite. Lithos, 238. 101-119 doi:10.1016/j.lithos.2015.09.011 | Journal (article/letter/editorial) | | A melt evolution model for Kerimasi volcano, Tanzania: Evidence from carbonate melt inclusions...Szabó, Csaba, A melt evolution model for Kerimasi volcano, Tanzania: Evidence from carbonate melt inclusions...MANUSCRIPT A melt evolution model for Kerimasi volcano, Tanzania: Evidence from carbonate melt IP T...compositions are similar to the parental melt of Kerimasi calciocarbonatite. Silicate-carbonate liquid immiscibility...A melt evolution model has been developed for Kerimasi. ACCEPTED MANUSCRIPT Abstract This study presents |  | | Journal (article/letter/editorial) | | from Pleistocene–recent volcanism in northern Tanzania J.B. Dawson ⁎ Grant Institute of Geosciences,...canoes in the Gregory Rift Valley of northern Tanzania (termed the Younger Extrusives) comprise one of...volcanism in northern Tanzania The Late Tertiary–Recent volcanic province of northern Tanzania is the most recently...and northern Tanzania. Because of its relatively young age (b~6 Ma), the northern Tanzania province contains...producing basalt and trachyte later), and the oldest volcano in the province, Essimingor — dated at 5.9–5.8 |  | Mangler, Martin F., Marks, Michael A.W., Zaitzev, Anatoly N., Eby, G. Nelson, Markl, Gregor (2014) Halogens (F, Cl and Br) at Oldoinyo Lengai volcano (Tanzania): Effects of magmatic differentiation, silicate–natrocarbonatite melt separation and surface alteration of natrocarbonatite. Chemical Geology, 365. 43-53 doi:10.1016/j.chemgeo.2013.11.027 | Journal (article/letter/editorial) | | Halogens (F, Cl and Br) at Oldoinyo Lengai volcano (Tanzania): Effects of magmatic differentiation, si...their alteration products from Oldoinyo Lengai (Tanzania) are compared to those of associated silicate...in natrocarbonatites from Oldoinyo Lengai volcano (Tanzania) and the associated silicate rocks in order...processes. 2. Oldoinyo Lengai Volcano Oldoinyo Lengai is located in Tanzania, approximately 16 km south...1995). System (Fig. 1). Age data suggest that the volcano has existed for more than 500 000 years (Bagdasarayan |  | Zaitsev, A. N., Chakhmouradian, A. R., Siidra, O. I., Spratt, J., Williams, C. T., Stanley, C. J., Petrov, S. V., Britvin, S. N., Polyakova, E. A. (2011) Fluorine-, yttrium- and lanthanide-rich cerianite-(Ce) from carbonatitic rocks of the Kerimasi volcano and surrounding explosion craters, Gregory Rift, northern Tanzania. Mineralogical Magazine, 75 (6) 2813-2822 doi:10.1180/minmag.2011.075.6.2813 | Journal (article/letter/editorial) | | rocks of the Kerimasi volcano and surrounding explosion craters, Gregory Rift, northern Tanzania A. N. ZAITSEV1...altered calcite carbonatite lava from the Kerimasi volcano, and as euhedral crystals up to 200 mm across...explosion craters in the Gregory Rift, northern Tanzania. X-ray powder diffraction data (a = 5.434(5) Å)...X-ray diffraction, crystal structure, Kerimasi, Kisete, Loluni, Tanzania. Introduction CERIANITE-(CE), ideally...cerianite-(Ce) in carbonatitic rocks in northern Tanzania, and report the physical properties and the crystal-chemical |  | | Journal (article/letter/editorial) | | eruption of Oldoinyo Lengai have been determined. Nyerereite phenocrysts are homogeneous, with average composition...Nc~vKcsCcls) with 0-30% oriented inclusions of exsolved nyerereite. Overgrowths on gregoryites (30 gm wide) are...less calcic than the composition of the 1-kbar nyerereite + gregoryite+liquid cotectic in the ternary system...Crystal size distributions of gregoryite and nyerereite in one sample are linear, implying little loss...which crystallize calcite cannot fractionate to nyerereite+gregoryite + liquid assemblages. Natrocarbonatites |  | | Report (chapter) | | It is fine grained, extrusive and composed of nyerereite ((Na,K)2Ca(CO3)2) and gregoryite From: FITTON...-/:/ ", KENYA u __-/~.'\- " :. / I 2 ~ i TANZANIA 9 ~ ' "q'/~'L I I I 3;"~I "". IIi1 A "...KILIMANJARO SADIMAN 9 100 L 1 i ! I ESSIMINGOR 4o TANZANIA 134~ ~ HANANG ~ 1380 FIG. 3. Map of Kenya...(non-carbonatitic) volcanic centres corresponding to the Kenyan region of the outer zone shown in Fig. 2. Between these...than 100 ppm. The Miocene lavas of the Kisingiri volcano in W Kenya provide a good example of the normal |  | | Journal (article/letter/editorial) | | A supposed s6vite from Oldoinyo Lengai, Tanzania" result of extreme alteration of alkali carbonatite...Lengai, Tanzania Introduction OLDOINYO LENGA1, situated in the Rift Valley of northern Tanzania, the world's...world's only active carbonatite volcano. The main part of the volcano is built of yellow nepbelinitic...agglomerate on the lower eastern slopes of the volcano. It was identified as a calcite carbonatite by...it as srvite in accounts of the geology of the volcano (Dawson, 1962, 1989). A re-examination of this |  | | Journal (article/letter/editorial) | | transformation of Oldoinyo Lengai natrocarbonatites, Tanzania Anatoly N. Zaitsev a,b,c,⁎, Jörg Keller c a Department...particular halides and gregoryite, and by hydration of nyerereite under the influence of meteoric water and (iii)...is common for the active northern crater of the volcano. Reaction of hot (54–141 °C) fumarolic gases with...natrocarbonatite lavas of the Oldoinyo Lengai volcano, East African Rift, Tanzania, consist of the water-soluble phenocryst...phenocryst minerals nyerereite and gregoryite, groundmass sylvite and halite and are black to dark grey |  | | Journal (article/letter/editorial) | | Na4Ca(CO3)3 decomposes to produce Na carbonate and nyerereite. The latter melts AC incongruently at 875±25...solutions, Na2Ca3(CO3)4, Mg-bearing shortite, nyerereite, eitelite, and Na carbonate. The primary solidification...compositions more alkaline than eitelite and nyerereite. Considering the present results and PT previous...Na2Ca2(CO3)3 (Amm2) shortite, Na2Ca(CO3)2 (P21ca) RI nyerereite, Na2Mg(CO3)2 ( ̅ ) eitelite (0.1 GPa) → Na2(Ca0...09)3(CO3)4 (P1n1), Na2(Ca≥0.81Mg0≤0.19)(CO3)2 ( ̅ ) nyerereite, Na2(Ca0.77Na4(Ca0.90-0.98Mg0.02-0.10)(CO3)3 |  | | Report (chapter) | | carbonate rocks. A nephelinite/phonolite volcano in Tanzania is currently erupting Na-Ca-K carbonate magma...represent the final residua expelled from the source region. Most large carbonatite intrusions seem to have...depth of erosion, and at the head is Kerimasi volcano, Tanzania, where James (1956) had just reported...one of the ironies of science, the twin volcano of Kerimasi, Oldoinyo Lengai, had been recorded as erupting...m a s Oldoinyo Lengai, in northern Tanzania, is the only volcano at which flowing carbonate magma has |  | | Journal (article/letter/editorial) | | Gregory Rift Valley (northern Tanzania) PT and is the only active volcano erupting natrocarbonatite lava...of abundant phenocrysts of alkali carbonates, nyerereite and gregoryite, set in a quenched groundmass...Woolley, 2003). Oldoinyo Lengai (Tanzania) is the sole active volcano that erupts carbonatites and provides...natrocarbonatite volcano in the world, is situated within the Gregory Rift Valley in northern Tanzania. Between...to subhedral phenocrysts of alkali carbonates, nyerereite Na2Ca(CO3)2 and gregoryite (Na2K2Ca)CO3, surrounded |  | | Journal (article/letter/editorial) | | Oldoinyo Lengai Geological setting Oldoinyo Lengai volcano is situated in the Gregory KEY WORDS: Oldoinyo...natrocarbonatiU; rilicate-tarbonaU Rift Valley of Tanzania 16 km south of Lake Natron immiscibility; East...include Kerimasi (Guest et al., 1961; Hay, tite volcano and the only currently active volcano in 1983;...silicate—natrocarbonatite textures clearly(Kerimasi, Tanzania; Shombole, Kenya) and have indicating an...nepheline, wollastonite and gre- Lengai is an exotic volcano which may have little goryite, interpreted as quenched |
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