 | | 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 |  | | 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 |  | 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...and matrix glass in peralkaline, silicaoversaturated trachytes from the Menengai volcano, Kenya Rift Valley...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 (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 |  | | Journal (article/letter/editorial) | | 73 www.elsevier.com/locate/lithos The central Kenya peralkaline province: Insights into the evolution...Available online 30 May 2006 Abstract The central Kenya peralkaline province comprises five young (< 1 Ma)... Keywords: Kenya; Petrogenesis; Peralkaline magmas 1. Introduction In the central Kenya Rift Valley...complexes. Three are trachytic caldera volcanoes (Menengai, Longonot and Suswa) and two are rhyolitic complexes...Recent peralkaline trachyte caldera volcanoes (Menengai, Longonot and Suswa) and peralkaline rhyolite |  | 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) | | open access at Springerlink.com Abstract Matrix glass and melt inclusions in phenocrysts from pantellerite...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...Whole-rock analyses of all four (Table 1), and matrix glass analyses of three, were presented in Ronga et al...relationships between whole-rock, glass and phenocryst phases. Phenocryst and matrix glass compositions were determined |  | | | | February 2009, Vol. 73(1), pp. 1–16 The central Kenya peralkaline province: a unique assemblage of magmatic...peralkaline salic complexes in the south-central Kenya Rift Valley, stressing new developments of general...very low viscosity of the magmas. K EY WORDS : Kenya Rift, peralkaline salic rocks, petrogenesis, plumbing...plumbing systems. Introduction THE central Kenya peralkaline province (CKPP) of Macdonald and Scaillet...area of ~6000 km2 in the south-central part of the Kenya Rift Valley (Fig. 1). It is unique in its juxtaposition |  | | 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 |  | | 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) | | 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 |  | Macdonald, Ray, Sumita, Mari, Schmincke, Hans-Ulrich, Bagiński, Bogusław, White, John C., Ilnicki, Sławomir S. (2015) Peralkaline felsic magmatism at the Nemrut volcano, Turkey: impact of volcanism on the evolution of Lake Van (Anatolia) IV. Contributions to Mineralogy and Petrology, 169 (4) doi:10.1007/s00410-015-1127-6 | Journal (article/letter/editorial) | | PAPER Peralkaline felsic magmatism at the Nemrut volcano, Turkey: impact of volcanism on the evolution of...open access at Springerlink.com Abstract Nemrut volcano, adjacent to Lake Van (Turkey), is one of the most...tephra samples, we document the phenocryst and glass matrix compositions, confirming a complete spectrum...intermediate-rhyolitic magmas. Keywords Nemrut volcano · Peralkaline magmatism · Magma mixing · Open-system...peralkaline eruptive rocks at the Nemrut caldera volcano, Turkey. Nemrut is the most active centre in Turkey |  | | Journal (article/letter/editorial) | | 12 – 9 Ma) is poorly represented in the Southern Kenya Rift, though magmatic activity is recorded in the...– 4 Ma) is particularly well-represented in the Kenya Rift. Large-scale magmatic events include: commencement...Divergence (NTD) and Mt. Kenya, Rungwe Volcanic Province, and the Southern Kenya Rift. The Stratoid Phase...magmatic events at ca. 3 to 2.5 Ma within the Southern Kenya Rift and NTD. This phase manifests as basalts and...that flood the newly formed graben in the Southern Kenya Rift. This phase also correlates with the main phase |  | 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) | | available to allow the use NU of new whole-rock, glass and phenocryst compositional data to (i) point out...separated pantelleritic glass (his sample D1000126). Sample N-90-NG is non-hydrated glass separated from a further...analytical precision (1σ; wt%) for all phases except glass are: Si 0.07, Ti 0.03, Al 0.02, Cr 0.02, Ni 0.03...Mn 0.03, Mg 0.04, Ca 0.08, Na 0.01, K 0.01. For glass analyses, 15 kV and 6-10 nA and a dispersed spot...used. Certain problems can arise with analysis of glass. As well as compositional variations related to |  | 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) | | 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...in air at 1200°C for 3 hours, then grinding the glass obtained to a 10-40 µm powder mesh size. This technique...technique produces a crystal-free homogeneous glass with a composition similar to the starting bulk rock...FTP. The determination of the water content in glass (H2Omelt) was difficult in most crystalbearing runs |  | | 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 |  | 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) | | clinopyroxene, feldspar, and titanomagnetite, as well as glass in variable proportions. The degree of crystallinity...crystallization is extremely high (>90%), and the residual glass obtained from trachyte experiments is characterized...eruptive products containing interstitial phonolitic glass within an anorthoclase framework. The shift from...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 |  | Bianchini, Gianluca, Brombin, Valentina, Marchina, Chiara, Natali, Claudio, Godebo, Tewodros Rango, Rasini, Alessandro, Salani, Gian Marco (2020) Origin of Fluoride and Arsenic in the Main Ethiopian Rift Waters. Minerals, 10 (5) 453 doi:10.3390/min10050453 | Journal (article/letter/editorial) | | anthropogenic activities. The weathering of volcanic glass and minerals (apatites, clays, hydro-oxides) by...sectors of the East African Rift and other similar volcano-tectonic settings. Keywords: fluoride and arsenic;...fluorite, apatite, amphibole, biotite, and volcanic glass contain F– and As [8,10–12,26–30]. Moreover, F–...Differentiated rhyolite magmas appeared late in the volcano-tectonic evolution of the area, marking the onset...MER, the rifting processes have formed various volcano-tectonic depressions, favouring the development |  | 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...particularly of fluorine (up to 1.8 wt.% in silicate glass) resulting in the formation of daughter fluorite...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 |  | | 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 |  | | Journal (article/letter/editorial) | | Mineral Petrol (2013) 165:283–304 285 glass bead. During glass synthesis, the melt is in direct contact...will be referred to as reduced starting glass (HAF red). Glass powder was used to promote nucleation of... Both types of capsules were filled with 50 mg glass powder (300 mg in composition of the dyke rock...was subsequently rapidly quenched in water. The glass pieces were ground to a grain size \300 lm, re-melted...lm). This glass will be referred to as oxidized starting glass (HAF ox). Half of the glass powder was |  | | 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 |  | | Report (issue) | | structures filled with a devitrified groundmass. Glass shards as well as the groundmass are typically devitrified...plinian-phreatomagmatic eruption at the Laacher See volcano, Germany. In that eruption, the lithic fragments...breccia fragments supported in a matrix of olivegreen glass. Phenocrysts are restricted to the breccia fragments...supported in a matrix of light green devitrified glass. Plastic scale is 15 cm long. 38 underlying caldera-forming...ash-flow tuff. The tuff consists of undistorted glass shards 0.5 to 1 mm long and sparse unflattened pumice |  | | Journal (article/letter/editorial) | | rock (WR)-glass analyses. Whole-rock analyses are wet-chemical determinations, wheras all glass analyses...analytical conditions (Novak 1985). Although volcanic glass quenched at the surface cannot preserve magmatic...than the ash-flow tuffs, but rhyolitic groundmass glass from the trachyte has contents similar to those...for which values were derived from analysis of a glass/whole rock pair. Models deriving Members V1, V2...Kane Springs Wash volcanic rocks and separated glass. Analyses were normalized to Leedey chondrite values |  | | Journal (article/letter/editorial) | | Sanshui Basin are all holocrystalline and lack other glass and melt inclusion components. The cpx-melt equilibrium...Sanshui Basin are all holocrystalline and lack other glass melt inclusion components. The cpx-melt equilibrium...analysis is very important to reconstruct the complex volcano plumbing systems. (1) (2) (3) (4) Clinopyroxenes...basaltic andesites of the ongoing activity at Arenal volcano, Costa Rica: Evidence from clinopyroxene and spinel...andesitic scoria from the 1995 eruptions of Ruapehu volcano, New Zealand. J. Petrol. 2002, 43, 2279–2303. [CrossRef] |  | Huang, He, Wang, Tao, Zhang, Zhaochong, Li, Chao, Qin, Qie (2018) Highly differentiated fluorine-rich, alkaline granitic magma linked to rare metal mineralization: A case study from the Boziguo’er rare metal granitic pluton in South Tianshan Terrane, Xinjiang, NW China. Ore Geology Reviews, 96. 146-163 doi:10.1016/j.oregeorev.2018.04.021 | Journal (article/letter/editorial) | | part of the STT, unmetamorphosed Carboniferous volcano-clastic rocks and limestones unconformably overlie...Tianshan Terrane (STT), ~47 km north of the Baicheng County, Xinjiang Uygur Autonomous Region (Fig. 1b). The...elements were determined using the NIST 612 standard glass. 6. Analytical results 6.1. Major and trace elements...contents up to 2.53 wt.% were reported in silicate glass of melt inclusions from Strange Lake rare metal...of A-type granitoids in South Tianshan. Baicheng County, Xinjiang: Acta Petrologica Sinica 30, 1595-1614 |
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