 | | Journal (article/letter/editorial) | | Kilombe Caldera, Kenya by G. J. H. McCALL Received 14 June 1963; taken as read 7 November 1964 CONTENTS...... CALDERA GENESIS COMPARISON OF KILOMBE AND MENENGAI WITH LUNAR CRATERS ACKNOWLEDGMENTS REFERENCES...is compared, together with that of the nearby Menengai caldera, with the beak structure of many lunar...as Eldalat), an extinct volcano situated near the town of Eldama Ravine in Kenya, forms a conspicuous mountain...G. J. H . McCALL giant calderas nearby (e.g. Menengai 35 square miles, Suswa outer caldera 40 square |  | | Journal (article/letter/editorial) | | Oversaturated Peralkaline Glassy Trachytes from Kenya by R. MACDONALD,1 D. K. BAILEY, 1 and D. S. SUTHERLAND2...Peralkaline felsic lavas from the central part of the Kenya Rift Valley were used by Bowcn as an illustration...newly analysed trachyte obsidians, from the Menengai volcano, with the pantellerites from other centres...GEOLOGY The central sector of the Rift Valley of Kenya is characterized by an abundance of felsic peralkaline...south-west of Lake Naivasha). To the south, the volcano of Longonot consists largely of trachytes, some |  | | Report (issue) | | NATURAL RESOURCES GEOLOGICAL SURVEY OF KENYA GEOLOGY OF THE NAKURU-THOMSON'S FALLSLAKE HANNINGTON AREA...number concerned. | , ', ' I GEOLOGY OF THE NAKURU-THOMSON'S FALLSLAKE HANNINGTON AREA DEGREE SHEET...Drainage into Ol Punyata Swamp (5) Drainage into Lake Nakuru and the surrounding plain (6) Drainage into Lake...(c) Dispei-Lake Hannington Phonolites (d) Lower Menengai Volcanics .. (e) Sirrkon Volcanics (ƒ) Bahati...Succession (a) Willan's Farm Porphyritic Trachyte (b) Nakuru Lake Syndicate Quarry Phonolite .. (c) Mbaruk Basalt |  | Macdonald, R., Bagiński, B., Leat, P.T., White, J.C., Dzierżanowski, P. (2011) Mineral stability in peralkaline silicic rocks: Information from trachytes of the Menengai volcano, Kenya. Lithos, 125 (1) 553-568 doi:10.1016/j.lithos.2011.03.011 | Journal (article/letter/editorial) | | rocks: Information from trachytes of the Menengai volcano, Kenya R. Macdonald a,b,⁎, B. Bagiński a, P.T...2011 Available online 17 March 2011 Keywords: Menengai volcano Peralkaline trachytes and rhyolites Mineral...silicaoversaturated trachytes from the Menengai volcano, Kenya Rift Valley. The dominant phenocryst assemblage...East African Rift System. Volcanic centres in the Kenya Rift Valley where pantelleritic trachytes have been...Eburru (Clarke et al., 1990; Ren et al., 2006), Menengai (Leat et al., 1984; Macdonald et al., 1970), Nasaken |  | | Report (chapter) | | 2015 Tectonics and volcanism of the southern Kenya Rift Valley and its influence on rift sedimentation...SUM M A RY: Volcanism in the northern half of the Kenya Rift Valley began at 30 Ma, and in the southern...and a narrow inner graben, but in the Naivasha-Nakuru sector voluminous trachytic volcanism completely...into closed structural basins. Evolution of the Kenya Rift Valley during the last 30 Ma is now moderately...outline of the history of the southern part of the Kenya Rift gives an account of the structural style and |  | Macdonald, Ray, Bagiński, Bogusław, Ronga, Fiorenzo, Dzierżanowski, Piotr, Lustrino, Michele, Marzoli, Andrea, Melluso, Leone (2012) Evidence for extreme fractionation of peralkaline silicic magmas, the Boseti volcanic complex, Main Ethiopian Rift. Mineralogy and Petrology, 104 (3) 163-175 doi:10.1007/s00710-011-0184-4 | Journal (article/letter/editorial) | | Geological setting The Boseti complex is a young volcano in the northern sector of the Main Ethiopian Rift...simultaneously with the formation of Gudda, the Bariccia volcano (Pleistocene-Holocene) formed in two stages. The...experimental glasses, Scaillet and Macdonald (2003); Menengai, Macdonald et al. (2011) In peralkaline trachytes...apatites in comendites of the Olkaria complex, Kenya. In contrast, Mahood and Stimac (1990) found lower...apatites from pantelleritic trachytes of the Menengai volcano, Kenya. The reasons why apatites from the more |  | | Report (chapter) | | peralkaline silicic rocks and caldera volcanoes of Kenya R. Macdonald Geological Society, London, Special...of Kenya R. Macdonald S U M M A R Y: The late-Quaternary trachytic caldera volcanoes of the Kenya rift...these centres. The southern basalt-absent centres (Menengai, Longonot and Suswa) show Krakatoa-style collapse...plutonic processes while the volcano is at the magmatic stage. In Kenya the late-Quaternary caldera volcanoes...on the seven centres of the inner trough of the Kenya rift (Fig. 1) but, where relevant, information from |  | | Journal (article/letter/editorial) | | a c t Young (b 1 Ma) volcanic complexes in the Kenya Rift Valley are used to outline recent progress...dome complexes, e.g. the Olkaria complex in the Kenya (Gregory) rift with an estimated volume of ~13 km...Ma) silicic complexes in the inner trough of the Kenya Rift Valley to outline recent progress in our understanding...scarce or absent. The southern group of calderas (Menengai, Longonot and Suswa) are composed almost entirely...Olkaria, the southern group constitutes the Central Kenya peralkaline province (CKPP) of Macdonald and Scaillet |  | | Journal (article/letter/editorial) | | elsevier.com/locate/lithos The volcano–pluton interface; The Longonot (Kenya) and Kûngnât (Greenland) peralkaline...Available online 18 March 2014 Keywords: Longonot volcano Kûngnât syenite complex Evolution of complementary...magma reservoir(s). The trachytic caldera volcano Longonot (Kenya Rift Valley) and the Kûngnât syenite complex...Kelleher and Cameron, 1990) and the Olkaria complex, Kenya (Macdonald et al., 2008; Marshall et al., 2009)...which can be considered to be a complementary volcano–pluton pair. Although the histories of the two |  | | Journal (article/letter/editorial) | | peralkaline trachyte and phonolite from the Suswa volcano, Kenya rift John Charles White a,⁎, Vanessa V. Espejel-García...Tower, Upper Hill, P.O. Box 10076–00101, Nairobi, Kenya a r t i c l e i n f o Article history: Received...February 2012 Keywords: Trachyte Phonolite Central Kenya Peralkaline Province a b s t r a c t Suswa is the...the southernmost volcanic center in the Central Kenya Peralkaline Province (CKPP) and represents the only...lavas and tuffs that built the initial shield volcano (pre-caldera, unit S1) and erupted during the first |  | Macdonald, R., Bagiński, B., Belkin, H.E., White, J.C., Noble, D.C. (2019) The Gold Flat Tuff, Nevada: Insights into the evolution of peralkaline silicic magmas. Lithos, 328. 1-13 doi:10.1016/j.lithos.2019.01.017 | Journal (article/letter/editorial) | | recorded it in comendites of the Olkaria complex, D Kenya Rift Valley, where it forms hexagonal crystals up... In Fig. 7a, an andesine core is mantled by anorthoclase showing a slight increase in K/Na ratio towards...D regular decrease in An content within the anorthoclase field. A more complex zonation is PT E shown... MA comenditic, with scarce phenocrysts of anorthoclase. A third component (or components) contained... Although comendites from the Olkaria complex, Kenya, PT E have F contents >1 wt% (Macdonald et al |  | Brenna, Marco, Pontesilli, Alessio, Mollo, Silvio, Masotta, Matteo, Cronin, Shane J., Smith, Ian E.M., Moufti, Mohammed Rashad Hassan, Scarlato, Piergiorgio (2019) Intra-eruptive trachyte-phonolite transition: Natural evidence and experimental constraints on the role of crystal mushes. American Mineralogist, 104 (12) 1750-1764 doi:10.2138/am-2019-6963 | Journal (article/letter/editorial) | | containing interstitial phonolitic glass within an anorthoclase framework. The shift from trachyte to phonolite...phonolitic melt, as well as of dissolution of anorthoclase from a crystal mush. Keywords: Trachyte, phonolite...Laacher See volcano (Germany; Harms et al. 2004), as well as caldera systems at Suswa volcano (White et...eruption along a wadi on the western side of the volcano. The crater rim (dashed) is well as in magmatic...the clinopyroxene. (f) BSE image of feldspar (anorthoclase) glomerocryst in the phonolite. Note the lack |  | Romano, Pierangelo, Scaillet, Bruno, White, John C., Andújar, Joan, Di Carlo, Ida, Rotolo, Silvio G. (2020) Experimental and thermodynamic constraints on mineral equilibrium inpantelleritic magmas. Lithos, 376. 105793pp. doi:10.1016/j.lithos.2020.105793 | Journal (article/letter/editorial) | | mineral phases occurring in pantellerite (i.e., anorthoclase, sodian clinopyroxene and amphibole, fayalitic...Liszewska et al., 2018; Eburru, Kenya: Ren et al., lP 2006; and Menengai, Kenya: Macdonald et al., 2011)....trachytic Montagna Grande-Monte Gibele shield volcano and several other pantellerite shields and lava...range of temperature and fO2. Alkali feldspar (anorthoclase) and clinopyroxene are present in each assemblage...nearly constant (aSiO2[Qz] ≈ 0.7 and NNO-2 at Menengai and aSiO2[Qz] ≈ 0.9-1.0 and NNO-2.0 to -1.5 at |  | Zaitsev, A.N., Marks, M.A.W., Wenzel, T., Spratt, J., Sharygin, V.V., Strekopytov, S., Markl, G. (2012) Mineralogy, geochemistry and petrology of the phonolitic to nephelinitic Sadiman volcano, Crater Highlands, Tanzania. Lithos, 152. 66-83 doi:10.1016/j.lithos.2012.03.001 | Journal (article/letter/editorial) | | petrology of the phonolitic to nephelinitic Sadiman volcano, Crater Highlands, Tanzania A.N. Zaitsev a, b,⁎...Mineral stability fields Sadiman volcano a b s t r a c t Sadiman volcano is located in the Crater Highlands...All rights reserved. 1. Introduction Sadiman volcano (3°11′S, 35°25′E), also known as Satiman, is part...as the 1.6–1.5 Ma Oldeani basalt–trachyandesite volcano (Dawson, 2008; Mollel et al., 2008; 2011). ⁎ Corresponding...Lemagarut, Oldeani and Ngorongoro (Fig. 1a). The volcano is well known having been previously cited as the |  | | Journal (article/letter/editorial) | | volume) phenocrysts of euhedral, sieve-textured anorthoclase as much as 2 cm An An An "364 PRECALDERA...compositions of zoned crystals long. Many of the anorthoclase crystals show strong zoning about sieve pockets...in size (Fig. 4). The larger sieve-textured anorthoclase grains have granular pyroxenes included in sieve...characterized by 20-35% phenocrysts of coarse (0.5 2 cm) anorthoclase, which commonly are zoned and may have well-developed...well-developed sieve texture. Between 2 and 5% of the anorthoclase phenocrysts contain cores or " g h o s t s " |  | Upton, B. G. J., Macdonald, R., Odling, N., Rämö, O. T., Bagiński, B. (2013) Kûngnât, revisited. A review of five decades of research into an alkaline complex in South Greenland, with new trace-element and Nd isotopic data. Mineralogical Magazine, 77 (4) 523-550 doi:10.1180/minmag.2013.077.4.11 | Journal (article/letter/editorial) | | magma chamber (or chambers) beneath a central-type volcano, exhibits various features of petrological interest...change from crystallization of ternary feldspar (anorthoclase) to sanidine. All the feldspars, however, were... such as the peralkaline trachytes of Menengai volcano, Kenya (Macdonald et al., 2011), and in experimental...and peralkaline rhyolites of the Olkaria complex, Kenya (Macdonald et al., 2008). The trend is taken to...envisages a situation akin to that at the Aden volcano, Yemen, where a pyroclastic cone of trachytic tuff |  | | Report (volume) | | 273 BAKER, B. H. Outline of the petroIogy of the Kenya rift alkaline province 293 MACDONALD,R. Quaternary...peralkaline silicic rocks and caldera volcanoes of Kenya 313 WOOLLEY, A. R. & JONES, G. C. The petrochemistry...on the peralkaline silicic central volcanoes of Kenya and also favours an origin by crystal fractionation...pyroclastic deposits around central volcanoes in Kenya often show striking variations in the abundance...on the peralkaline silicic central volcanoes of Kenya and also favours an origin by crystal fractionation |  | | Report (volume) | | continents. Field work was conducted in Chad, Ethiopia, Kenya, Malawi, Nigeria, Sudan, Tanzania and Uganda. However...Baker, B.FL Tectonics and volcanism of the southern Kenya Rift Valley and its influence on rift sedimentation...structures, salic volcanism and sedimentation in the Kenya Rift from the equator northwards to Lake Turkana...from seismic and gravity data. 75 Watkins, R.T. Volcano-tectonic control on sedimentation in the Koobi...landtorm evolution in a rift valley basin, northern Kenya. Frostick, L.E. & Reid, I. Evolution and sedimentary |  | | Book | | Mineralogical Society of America (Fig. 6.6), Montserrat Volcano Observatory (Fig. 7.4a and the front cover image)...previously erupted products the hazard presented by a volcano to surrounding communities; • investigating magma...chamber that originally lay 5 km below an active volcano (but whose contents – or erupted products – are...alkali basalts that have erupted at later stages of volcano development. To show how this can be applied, the...accelerates the melt upward; vesiculation in a volcano vent therefore promotes lava fountaining at the |  | | Book | | carbonatitic-alkaline province outcropping on the Kenya-Uganda border which have recently received significant...domain characterized East Africa from Madagascar and Kenya-Ethiopia to northeastern Sudan. It represents the...Popoff 1988a). Like the Atlantic Benue trough, the Kenya-Sudan Mesozoic trends could correspond to a failed...Segoufin and Patriat 1981; Mougenot et al. 1986). The Kenya-Sudan Mesozoic troughs hypothetized above could...East-African rift. This suggests that the Mesozoic NW-SE "Kenya-Sudan" rift-system has been reactivated, similarly |
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