africa mining eastDiese Seite übersetzen

    Mining in East Africa East Africa is a significant supplier of rutile (titanium oxide), titanium-iron-oxide mineral ilmenite, gold and zircon. The majority of minerals produced in East Africa are exported for further processing and in, East African countries exported minerals worth US$.6m, a year-on-year decrease of.2%, reflecting a ...

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    Symplectitic augite from the Platreef – textural evidence ... · PDF Datei

    FREDERICK ROELOFSE AND LEWIS D. ASHWAL SOUTH AFRICAN JOURNAL OF GEOLOGY 23 Figure 2.(a) Photomicrograph showing symplectitic augite 'invading' a larger grain of non-symplectitic augite.Note the small grain of 'invading' non-symplectitic augite having the same orientation as that of the symplectitic augite towards the bottom of the photograph.

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    Pyroxene exsolution in mafic granulites from the .Diese Seite übersetzen

    Abstract. Exsolution textures were observed in clinopyroxenes in mafic granulites from the Grove Mountains, East Antarctica. The first generation of exsolution occurs only in subcalcic augite megacrysts, in which coarse orthopyroxene lamellae exsolved parallel to the (100) plane.

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    Mount Kenya, Meru County, KenyaDiese Seite übersetzen

    Mount Kenya, Meru County, Kenya : Mount Kenya straddles Meru County, Nyeri County and the northern most portion of Kirinyaga County. It has been located as Meru County due to the National Park being largely in Meru ...

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    Age and Polarity of the Turkana Lavas, North .Diese Seite übersetzen

    THE extension of the Trap Series of Ethiopia into north-west Kenya has previously been suggested on stratigraphical and petrological grounds1. This area has recently been mapped on the basis of a ...

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    Melilite-group minerals at Oldoinyo Lengai, Tanzania · PDF Datei

    Melilite-group minerals at Oldoinyo Lengai, Tanzania Daniel Wiedenmanna,b,⁎, Jörg Kellerc, Anatoly N. Zaitsevd,e a Department of Geosciences, University of Fribourg, Pérolles, 1700 Fribourg, Switzerland b EMPA, Swiss Federal Laboratories for Materials Testing and Research, Hydrogen and Energy, Überlandstrasse 129, 8600 Dübendorf, Switzerland c Institut für Geowissenschaften, Mineralogie ...

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    Pumice | volcanic glass | BritannicaDiese Seite übersetzen

    Pumice, a very porous, frothlike volcanic glass that has long been used as an abrasive in cleaning, polishing, and scouring compounds. It is also employed as a lightweight aggregate in precast masonry units, poured concrete, insulation and acoustic tile, and plaster. Pumice is pyroclastic igneous

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    Geological Mapping and Structural Setting of the Archean ... · PDF Datei

    When olivine and more iron-rich augite are present, the rock grades into ferrodiorite, which is transitional to gabbro. The presence of significant quartz makes the rock type quartz-diorite or tonalite, and if orthoclase (potassium feldspar) is present at greater than ten percent the rock type grades into monzodiorite or granodiorite.

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    IGNEOUS PETROLOGY - Earth scienceDiese Seite übersetzen

    The East African Rift which extends from Syria in the north to Mozambique in the south has been active throughout the Cenozoic. During the initial stages of rifting fissure eruptions produced large volumes of basalt and siliceous ignimbrites.

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    Pyroxene exsolution in mafic granulites from the .Diese Seite übersetzen

    Abstract. Exsolution textures were observed in clinopyroxenes in mafic granulites from the Grove Mountains, East Antarctica. The first generation of exsolution occurs only in subcalcic augite megacrysts, in which coarse orthopyroxene lamellae exsolved parallel to the (100) plane.

    Cited by: 20
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    Nepheline crystals inside lapilli, Ol Doinyo .Diese Seite übersetzen

    Nepheline crystals inside lapilli, Ol Doinyo Lengai, East Africa This summer I had a great opportunity to work for the Geology Department, University of Illinois, Urbana-Champaign. ... It is located in the East African Rift, the active rifting system.

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    Magmatic evolution of the Shira Volcanics, Mt .Diese Seite übersetzen

    Mt Kilimanjaro, Africa's highest mountain (5895m), is a large, young (<1.6Ma) stratovolcano at the southern end of the East African Rift, in northern Tanzania. Consisting of three distinct volcanic centres, Shira, Mawenzi and Kibo, Shira contains the highest proportion of mafic rocks.

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    Chapter 19: Continental Alkaline Magmatism · PPT-Datei Datei · Webansicht

    Chapter 19: Continental Alkaline Magmatism Alkaline rocks occur in all tectonic environments, including the ocean basins Conversely, Chapters 12, 15, 17, and 18 have shown us that magmatism on the continents can be highly varied, including tholeiitic and calc-alkaline varieties

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    Nepheline syenite - WikipediaDiese Seite übersetzen

    Nepheline syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar.The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are also known. Phonolite is the fine-grained extrusive equivalent.

    Primary: alkali feldspar, nepheline, clinopyroxene, .
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    Isotopic and geochemical evidence for a heterogeneous ... · PDF Datei

    Isotopic and geochemical evidence for a heterogeneous mantle plume origin of the Virunga volcanics, Western rift, East African Rift system Ramananda Chakrabartia,1, Asish R. Basua,⁎, Alba P. Santob, Dario Tedescoc, Orlando Vasellib a Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY-14627, USA b Dipartimento di Scienze della Terra Via G. La Pira, 4-50121 ...

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    The Cenozoic magmatism of East Africa: Part V – .Diese Seite übersetzen

    The generation of magmas in the East African Rift System (EARS) is largely the result of either: (A) melting of easily fusible compositions located within the lithospheric mantle due to thermobaric perturbations of the lithosphere, or (B) melting of the convecting upper mantle due to decompression caused by thinning of the plate during extension.

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    Sediments of the Gulf of Mexico | SpringerLinkDiese Seite übersetzen

    The Gulf of Mexico is a Mediterranean-type sea with limited fetch and low tidal ranges (microtidal) throughout. This basin is somewhat like a miniature ocean in that it contains all of the main bathymetric provinces of an ocean along with a complicated coastal zone (Figure 3.1).This chapter will consider the overall nature of the basin with emphasis on the sediments it contains.

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    Post-Pan-African tectonic evolution of ... - .Diese Seite übersetzen

    Tectonophysics, 191 (1991) 55-73 Eisevier Science Publishers B.V., Amsterdam 55 Post-Pan-African tectonic evolution of South Malawi in relation to the Karroo and Recent East African Rift Systems C. Castaing Bureau de Recherches Glogiques et Minies, Dartement Glogie, B.P. 6009, 45060 Orlns Cedex 02, France (Received March 5,1990; revised version accepted October 5,1990) ABSTRACT Castaing, .

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    Alkali basalt - WikipediaDiese Seite übersetzen

    Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields. Alkali basalt is characterized by relatively high alkali (Na 2 O and K 2 O) content relative to other basalts and by the presence of olivine and titanium-rich augite ...

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    GEOLOGY OF THE KAJIADO AREA - Library - WUR · PDF Datei

    In his report on the East African ProtectorateH.B. MufF (Maufe, ) described the Kapiti plains, recognizing the phenocrysts of felspar and nepheline in the Kapiti Phonolite, and realized that younger lavas overlay it toward (Muffs Nairob 1908,,i p. 33). He men­

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    Fine Collector Mineral Specimens - Andy SeibelDiese Seite übersetzen

    An extremely fine and old-time copper of sharp complex crystals. The depth is rather good and rarely do you get them so three dimensional. This piece emits a rich coppery patina from all sides and there is no real point of attachment.

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