 | | Journal (article/letter/editorial) | | African Rift System. Insert map shows parts of East Africa, with the location of the two rift branches, and...undertaken on nephelinite lavas from Napak and Mount Elgon volcanoes, eastern Uganda-western Kenya (Simonetti...Cr-spinel Olivine, clinopyroxene, Cr-spinel, perovskite, Ti-rich magnetite 11503 Mafurite 11513 Katungite...melt and fluid, orthopyroxene, Ti-rich magnetite Perovskite, apatite, phillipsite, nepheline, Cr-spinel,...magnetite phillipsite Ti-rich magnetite, apatite. Perovskite, nepheline, kalsilite, glass Cr-spinel, fluid |  | | Journal (article/letter/editorial) | | activity{s seenin manymountainand hill {eatures{rom Elgon {n the extreme southto the Zulla-Lotukei complexwhich...degreeo{ dissection;they include, {tom southto north, Elgon (14,178 it.), Kadam (10,050 it.), Napak (8,300 ...occurwithin 20 miles o{ the southwestern {oot o{ Mount Elgon andare now generallymarkedby a carbonatltecorewhichstandsabove...which is at presententirelycovered'bythe rocks{rom Elgon and whosepresenceis in{erred{rom evidencegivenby...or more. Thesecomplexes(includingsmallpatchesof Elgon tuffs overlying the carbonatitesof Sekululoand Bukusu) |  | | Journal (article/letter/editorial) | | plagioclase-bearing suite of lavas and a southern (Elgon) melilite-bearing suite are derived by different...Yelele, and other Eastern Uganda centres, e.g. Elgon (Davies, 1952). The rocks are invariably melanocratic...37) records forsterite in a similar rock from Mount Elgon. In addition rare ovoid phenocrysts of pale brown...red-brown biotite, apatite, and iron-stained magenta perovskite. The biotite is poecilitic and contains a second...occur in accessory quantities together with pink perovskite, small amounts of interstitial (? primary) carbonate |  | | Report (issue) | | works at Sukulu; the south-eastern slope of Mount Elgon is seen in the background. THE GEOLOGY OF PART...51 52 Petrography .. Vl INDEX-coutiuued. The Elgon Series Bugislzu Series Agglomerates and Lavas 53...Outcrops are usually poor in the areas away from the Elgon cliff and information has been gained in this region...to the west and the foothills and main cliff of Elgon to the east. The resultant variation in height,...the vertical cliffs formed by the agglomerates of Elgon which in many places are up to 1,000 feet in height |  | | Report (issue) | | itself as a mass of size comparable with that of Mt. Elgon. A branch of the Kavirondo Gulf rift valley runs...the structures is given. Pyrochlore, Columbian perovskite, apatite and magnetite are present in the carbonatite...dissected volcano, of even larger areal extent than Mount Elgon. The slopes are steep, traversed by numerous...produced by the Aircraft Operating Company of South Africa for Kenya Consolidated Goldfields Limited (1937-1939)...can be found in volume 8 of "Fossil Mammals of Africa" (Hopwood and Hollyfield, 1954). HI.—PHYSIOGRAPHY |  | | Journal (article/letter/editorial) | | granites appear beneath an outlier of volcanics of the Elgon series. Arcuate shear structures occur and the fenites...but since it has been revealed from beneath the Elgon volcanics by the active downcutting of the Siroko...some varieties, black ore is ubiquitous, while perovskite and apatite are common accessories. The central...and apatite are widespread, magnetite-ilmenite, perovskite and biotite occur in some rocks, while cancrinite...colourless diopside, together with magnetite-ilmenite, perovskite, apatite, and a very pale sphene. A bright, orange-brown |  | | Journal (article/letter/editorial) | | Rift Escarpment Fig. 1. Regional geology of East Africa fhowing part of the Tanzanian Shield, the East...grains of the same minerals, plus pyrrhotite, perovskite, Ti-magnetite, melilite and peralkaline silicate...wollastonite, glass (commonly palagonitized) and perovskite or titanite. The magmatic plutonic rocks, ranging...nepheline, titano-magnetite, apatite, Tiandradite, perovskite and wollastonite. One of the plutonic blocks...be compared with those for nephelinites from Mount Elgon and Napak. A few samples of nephelinite from |  | | Report (chapter) | | volcanoes composed of a great variety of lavas formed Mount Kenya and Kilimanjaro (Ke and Ki). Within the rift...pyroclastic rocks and debris flows, exemplified by Mounts Elgon, Napak, Meru, Hanang and O1 Doinyo Lengai. They...(Moroto (Mo) Yelele (Ye), Napak (Na), K a d a m (Ka), Elgon (El), Kisingiri, Wasaki and the early phase of Tinderet...greater proportion of phonolites (Le Bas 1977). Mount Elgon (EG) on the Uganda border and the Kishalduga...phenocrysts, with or without olivine and/or melilite. Perovskite is present in some lavas, and the phonolites |  | | Journal (article/letter/editorial) | | from Napak Volcano, eastern Uganda [7], and Mount Elgon Volcano, eastern Uganda–western Kenya [8]. This... phlogopite, and, sporadically, melilite and perovskite. The groundmass of the rock comprises also kalsilite...Bell, “Nd, Pb and Sr Isotopic Data from the Mount Elgon Volcano, Eastern Uganda–West ern Kenya: Implications |  | | Report (chapter) | | largely through the impact of work in Scandinavia and Africa. Br6gger's work (1921), at Fen in S Norway, which...(1935) were the first to identify carbonatites in Africa. Garson re-investigated the Malawi complexes of...carbon- atitic complexes of different ages in E Africa and reveals that, while the high-field-strength...elements. The younger complexes of Homa Mountain and Elgon both show a slight enrichment in Ba and Th, and...nephelinitic lavas from carbonatitic and other provinces Elgon, WKenya Kisingiri, W Kenya Napak, EUganda RR659 |  | | Journal (article/letter/editorial) | | to the presence of phenocryst minerals such as perovskite and melanite. Many nephelinites and their intrusive...rocks from Shombole and Oldoinyo L'engai, East Africa (Fig. 1), examines the origin and evolution of...commonly contains accessory minerals such as perovskite, melanite, and sphene. With increasing SiOz content...this type (e.g., Kisingiri, Kenya: Le Bas 1977; Mount Elgon, Uganda: King 1965; Kwaraha, Tanzania: Gerasimovsky...sample SH-49 (open circle), a carbonate-rich perovskite melanephelinite from Shombole. All of these lavas |  | | Journal (article/letter/editorial) | | Liquid Immiscibility at Shombole Volcano, East Africa: Petrographic and Experimental Evidence B. Kjarsgaard...two nephelinite lavas from Shombole volcano, East Africa, and discuss its significance for carbonatite petrogenesis...Liquid Immiscibility at Shombole Volcano, East Africa 295 with associated carbonatite dikes or extrusive... the Kaiserstuhl, W. Germany: Keller, 1981; Mount Elgon, Uganda: King and Sutherland, 1966). Most carbonatites...from silica-poor nephelinites (40~o SiO2) with perovskite and melanite microphenocrysts, to titanite-bearing |  | | Journal (article/letter/editorial) | | soda-melilite, monticellite, Mg-Mn-ilmenite, perovskite, serpentine, Fe-Mg-Ti-Mn-Cr-Al-spinels±glass...broadly to basanites and nephelinites, and lack the perovskite, Mg-ilmenite, eckermannite and melilite of UML...California, San Francisco on December 13, 2014 Africa (18) Ml. Elgon. Kenya/Uganda (19) Homa Bay a n a , Kenya...Alnotte, aillilcile Alnotle, aillilulc Parts of Elgon nephdinitc volcano Parts of Rangwa/Homa carbonatite...lamprophyres Area and country (Letter on Fig. I) Southern Africa (A) Sutherland area Associated alkaline igneous |  | | Journal (article/letter/editorial) | | petrology of Shombole and Oldoinyo L'engai, East Africa Tony D. Peterson The Geological Survey of Canada...cpx + nepheline + accessory minerals range from perovskite-bearing nephelinites (43% SiO2, volatile-free)...concentrations ( ~ 10 ppm); fractionation of perovskite, melanite, sphene, and apatite produced negative...(Kenya) Rift. Prominent centres in this series are Mount Elgon, eastern Uganda (King 1965; King and Sutherland...fragments (clinopyroxene, nepheline, melanite, and perovskite). The oldest lavas exposed at Shombole, found |  | | Book (edition) | | Venezuela, Brazil, Paraguay, Angola and South-West Africa, i.a. Carbonatites are now the major sources of...Canada Brazil Greenland, Europe, and the U.S.S.R. Africa India APPENDICES REFERENCES LOCALITY INDEX SUBJECT...of South Africa and C. A. Strauss and F. C. Truter (1950A) : Geological Society of South Africa and R....Society of South Africa and R. L. Johnson (1961) 6-12: Geological Society of South Africa and R. L. Johnson...Figure Figure 10-1: Geological Society of South Africa and S.J. Shand (1921A) 10-5: American Journal of |  | Ulrych, J., Lloyd, F. E., Balogh, K., Hegner, E., Langrová, A., Lang, M., Novák, J. K., Řanda, Z. (2005) Petrogenesis of alkali pyroxenite and ijolite xenoliths from the Tertiary Loučná–Oberwiesenthal Volcanic Centre, Bohemian Massif in the light of new mineralogical, geochemical, and isotopic data. Neues Jahrbuch für Mineralogie - Abhandlungen, 182 (1) 57-79 doi:10.1127/0077-7757/2005/0029 | Journal (article/letter/editorial) | | volcano, Tanzania (Dawson & Smith 1972) and from Elgon in Uganda (Davies 1952). Alkali pyroxenite xenoliths...fine-grained (0.3–0.5 mm) massive, coarse-grained; perovskite phenocrysts (up to 2 mm) in argillitized whitish...phenocrysts of K-feldspar > Fe-biotite; accessoric perovskite in fine-grained matrix 60 J. Ulrych et al...K-feldspar Phlogopite Amphibole Rhönite Apatite Garnet Perovskite Titanite Total tr. 17 57 11 tr. 14 64 17 tr...xene shows fine oscillation zoning. Accessory perovskite with titanian magnetite, apatite, and titanite |  | | Journal (issue) | | AND KIMBERLITES Kimberlitic Volcanoes in East Africa. By Peter H. Nixon, BSc, PhD, MIMM, formerly Geological...and section . . . Kimberlitic Volcanoes in East Africa Fig. I Fig. 2 Fig. 3 Locality Map. Main faults...ment, with special reference to East and Central Africa. The guests and delegates were to be invited from...one regional meeting for geologists in eastern Africa had been held since 1959. The Conference was attended...geophysical approach was applicable to equatorial Africa, and concluded that Canadian methods would have |  | | Journal (article/letter/editorial) | | nepheline, monticellite, melilite, pyrochlore, perovskite, niocalite, magnetite, wollastonite, richterite...(40–10%), and minor or accessory amounts of hauyne, perovskite, apatite, biotite, magnetite and calcite. Amongst...In contrast, Cox and Wilton (2006) obtained a perovskite age from carbonatite by LA-ICP-MS of 131 ± 7...Melilite Melanite Wollastonite Pyrochlore Perovskite Pyroxene Nepheline 30 25 7 30 20 3 Niocalite...rock, with accessory calcite, apatite, biotite, perovskite and other oxides; examples include samples Oka137 |  | Milani, Lorenzo, Bolhar, Robert, Frei, Dirk, Harlov, Daniel E., Samuel, Vinod O. (2017) Light rare earth element systematics as a tool for investigating the petrogenesis of phoscorite-carbonatite associations, as exemplified by the Phalaborwa Complex, South Africa. Mineralium Deposita, 52 (8) 1105-1125 doi:10.1007/s00126-016-0708-2 | Journal (article/letter/editorial) | | as exemplified by the Phalaborwa Complex, South Africa Lorenzo Milani 1 & Robert Bolhar 1 & Dirk Frei...Witwatersrand, PVT Bag 3, Wits, Johannesburg 2050, South Africa 2 Department of Earth Sciences, University of...Western Cape, PVT Bag X17, Bellville 7530, South Africa 3 Department of Earth Sciences, Stellenbosch...Stellenbosch University, PVT Bag X1, Matieland 7602, South Africa 4 GeoForschungsZentrum Potsdam Telegrafenberg...Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa 6 Centre for Earth Sciences, Indian Institute |  | | Report (chapter) | | explanation. Half of the known carbonatites are in Africa, and their timing and distribution indicate that...half of which are in Africa). In choosing 11 examples from the 23 known in Africa at that time Campbell...discoveries following the second world war were in Africa, and Campbell Smith had played a crucial part in...a normal part of the magmatic history . . . of Africa over a long period of geological time'. This aspect...the sub-volcanic complexes in East and Central Africa. His selected African examples are listed in order |  | Koornneef, Janne M., Davies, Gareth R., Döpp, Sonja P., Vukmanovic, Zoja, Nikogosian, Igor K., Mason, Paul R.D. (2009) Nature and timing of multiple metasomatic events in the sub-cratonic lithosphere beneath Labait, Tanzania. Lithos, 112. 896-912 doi:10.1016/j.lithos.2009.04.039 | Journal (article/letter/editorial) | | 112S (2009) 896–912 Fig. 1. Map of East Central Africa showing Rift valleys, the craton and the surrounding...K)1−2(Si,Al)8O16·6(H2O)), Ba-aluminosilicate and perovskite. This latter metasomatic event, which resulted...polymict xenoliths from Bultfontein, Kaapvaal, South Africa (Lawless et al., 1979; Zhang et al., 2001; Höfer...Age of volcanic rocks in the rift zones of East Africa. Geochemistry International 10, 66–71. Becker,...1984. Isotope geochemistry of xenoliths from East Africa: implications for development of mantle reservoirs |  | | Journal (article/letter/editorial) | | Toro—Ankole Regions, East and Central Equatorial Africa by KEITH BELL 1 and j . L. POWELL (Received 9...1962), and the Birunga region of Central Equatorial Africa (Holmes & Harwood, 1937; Holmes, 1950; Higazy,...are: The undersaturated potassic lavas of East Africa are closely associated with the Rift Valley System...melilite+potash-rich glass all with abundant olivine, perovskite, and black oxide mineral, dibiotite, itglass...province had a different origin from those of East Africa, or whether their samples were not sufficiently |  | | Journal (issue) | | INVESTIGATED IN OUR LABORATORY KNHPP E B.RTESLIMITED AFRICA HOUSE, KINGSWAY, LONDON, W.C.2 Telephone : CHA...-Uganda . • • • • • • • 191 BOOK REVIEWS Africa. A Study in Tropical Development. By L. D. Stamp...141 143 146 ABSTRACT ECONOMIC DEVELOPMENT IN AFRICA, AUSTRALIA AND IN MANY OTHER PAR'I'S OF...summer in some communities (U.S.G.S. 1950). In South Africa, the developments of agriculture, forestry, and...continent is checked by insufficient water. Throughout Africa, this problem is of the utmost importance. In many |  | | Book (edition) | | in 1927, when the author was resident in South Africa and library facilities were of the poorest. The...Scotland ... 19. Skeleton crystals of apatite, South Africa ... 20. Melanite in ijolite, Transvaal 21. Olivine-anorthite... Plan and section of Tabankulu Mountain, South Africa ... 38. The Great Dyke, Rhodesia ... 39. Koniakowsky...leucite have been observed in perfectly fluid lava at Mount Vesuvius. It follows, then, that we are justified...composition of two examples of this mineral from East Africa is expressed as follows (Bowen and Ellestad), Soda-nepheline |  | | Book (edition) | | Scotland ... Skeleton crystals of apatite, South Africa 17. -Melanitc in ijolite, Transvaal 18. Olivine-anorthite...Bushveld norite, Transvaal Tabankulu Mountain, South Africa 43. The Great Dyke, Rhodesia Koniakowsky Hill...leucite have been observed in perfectly fluid lava at Mount Vesuvius. ; follows, then, that It and other...of this mineral holds roughly five from East Africa is times aS much soda expressed as follows...titania takes The part. CaSiTiOg CaTiOg Sphene Perovskite Astrophyllite ^^nigmatite and rhonite are Fe |
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