 | | Journal (article/letter/editorial) | | Peralkaline syenite autoliths from Kilombe volcano, Kenya Rift Valley: Evidence for subvolcanic interaction...geochemistry of syenite autoliths from Kilombe volcano indicate that they crystallized in the upper parts...replacement of (i) Mg–hedenbergite by aegirine–augite, Ca–aegirine and/or aegirine, (ii) fayalite by amphiboles...These latter represent new mineral occurrences in Kenya. © 2006 Elsevier B.V. All rights reserved. Keywords:...Keywords: Syenite; Carbonatite; Kilombe; Kenya rift valley; Ce-anomaly; REE–fluorcarbonate ⁎ Corresponding |  | | Journal (article/letter/editorial) | | elsevier.com/locate/lithos The volcano–pluton interface; The Longonot (Kenya) and Kûngnât (Greenland) peralkaline...2014 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...syenitic cumulates, can be inferred to exist in the Longonot magma chamber. At Kûngnât, the intermittent development...Kelleher and Cameron, 1990) and the Olkaria complex, Kenya (Macdonald et al., 2008; Marshall et al., 2009) |  | Macdonald, R., Kjarsgaard, B. A., Skilling, I. P., Davies, G. R., Hamilton, D. L., Black, S. (1993) Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya. Contributions to Mineralogy and Petrology, 114 (2) 276-287 doi:10.1007/bf00307762 | Journal (article/letter/editorial) | | between trachyte and carbonate in ash flow tufts from Kenya R. Macdonald 1, B.A. Kjarsgaard 2, 4, I.P. Skilling...thin, syn-caldera ash flow tufts of the Suswa volcano, Kenya, contain pumiceous clasts and globules of trachytic...for COa in the petrogenesis of the salic rocks of Kenya has been repeatedly advocated by Bailey (eg. 1978...coexisted with peralkaline trachyte at the Longonot volcano. In this paper, textural, mineralogical and...on trachytic ash flow tuffs from the Suswa volcano, Kenya, are interpreted as providing exceptionally |  | 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) | | Information from trachytes of the Menengai volcano, Kenya R. Macdonald a,b,⁎, B. Bagiński a, P.T. Leat...Available online 17 March 2011 Keywords: Menengai volcano Peralkaline trachytes and rhyolites Mineral stability...silicaoversaturated trachytes from the Menengai volcano, Kenya Rift Valley. The dominant phenocryst assemblage...centres in the Kenya Rift Valley where pantelleritic trachytes have been recorded include Longonot (Rogers et...Barberi et al. (1975); Longonot, Kenya, unit Lt2b, Rogers et al. (2004); Olkaria, Kenya, Macdonald et al. |  | | Report (issue) | | 55 GOVERNMENT OF KENYA* MINISTRY OF COMMERCE AND INDUSTRY GEOLOGICAL SURVEY OF KENYA GEOLOGY OF THE...the Naivasha area, in the south-central part of Kenya Rift Valley, was probably the best known part of...Pleistocene exit the Njorowa Gorge, Mount Longonot a young volcano, and numerous other volcanic cones, is...accounted one of the more scenically beautiful parts of Kenya. Mr. Thompson and Mr. Dodson have succeeded in making...-The maximum extent of the Gamblian Lake between Longonot and Menengai .. .. .. .. .. .. .. .. .. 5 -Njorowa |  | 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...associated, in the matrix, with alkali feldspar, aegirine-augite, aenigmatite, quartz and tiny grains of ilmenite...contact with phenocrysts. Other phases are aegirine-augite (px), sanidine (Kfs), quartz (Q), aenigmatite...Fe-rich crystals. Ronga et al. (2010) reported aegirine-augite rims (with Na2O up to 5.2 wt.%) to hedenbergite |  | Spandler, Carl, Morris, Caitlin (2016) Geology and genesis of the Toongi rare metal (Zr, Hf, Nb, Ta, Y and REE) deposit, NSW, Australia, and implications for rare metal mineralization in peralkaline igneous rocks. Contributions to Mineralogy and Petrology, 171 (12) doi:10.1007/s00410-016-1316-y | Journal (article/letter/editorial) | | often protruded by aegirine and feldspar phenocrysts and contain swarms of fine aegirine and feldspar grains...5–0.7], and titanomagnetite, usually with aegirine-augite and/or arfvedsonite (see Electronic Appendix...may be of hydrothermal origin. The pyroxene is aegirine (Electronic Appendix 1) and occurs as occasional...quartz may be found interstitial to feldspar and aegirine in the matrix. The main ore minerals include Na–Ca–Zr...with only the albitic cores of phenocrysts and aegirine micro-phenocrysts remaining free of alteration |  | | Journal (article/letter/editorial) | | et al., 1996; Zaire: Bailey and Hampton, 1990; Kenya: Scott, 1982), or as discrete carbonate droplets...ne-bearing alkalifeldspar syenite with macroscopic aegirine-augite and hornblende, whereas ne-monzosyenite varieties...intrusion that is characterized by alkali-feldspar and aegirine (Prins, 1981; Bühn and Rankin, 1999). The centre...alteration, which includes secondary growth of aegirine in veins. Total procedural blanks were < 50 pg...MnO MgO CaO Na2O K2O H2O Total Fo Fa Mt Te Augite Aegirine Jadeite X usp X mag X herc X spinel ol 2 |  | | 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 |  | | 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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