 | | Journal (article/letter/editorial) | | and Okenyenyaigneous complexes, north-western Namibia Received: 10 August 1993/Accepted: 15 January...units of the Brandberg and Okenyenya igneous complexes, northwestern Namibia, confirm the Early Cretaceous...rocks of Okenyenya, 133.3 _+ 1.4 to 129.2 _+ 0.7 Ma. The mean K - A r age of the Okenyenya complex is essentially...dating of this complex (129.1-123.4Ma). K - A r chronology for the Brandberg complex is in conflict with...layered intrusion yields the oldest age from the complex, 135.2 4- 1.4 Ma. The concordancy of age measurements |  | | Journal (article/letter/editorial) | | felsic magmatism in the Cretaceous Paresis ring complex, Namibia: evidence for mixing of crust and mantle-derived...with subordinate intrusions of quartz syenite and alkali-feldspar syenite. These felsic units are accompanied...the farthest inland of any felsic complex in the Cretaceous ring complex group. The other ring complexes...rhyolites and peraluminous, more differentiated quartz-feldspar rhyolites. Both units show prominent negative...the Congo craton and related inliers in northern Namibia. The comendites are peralkaline, highly differentiated |  | | Journal (article/letter/editorial) | | extensive crustal contamination in the Okenyenya igneous complex, Namibia I13MA A. MARTINEZ,J CHRIS HARRIS...Energy, Geological Survey, P.O. Box 2168, Windhoek, Namibia (Received August 9, 1995; accepted in revised...rock types from the 130 Ma Okenyenya igneous complex of northwestern Namibia. These rock types include...gabbro to quartz monzodiorite and syenite, and an alkaline suite including gabbro, syenite, nepheline...nepheline syenite, and essexite. In general, the difference in 6~80 values between coexisting feldspar, pyroxene |  | | Journal (article/letter/editorial) | | Isotope characteristics of the Okenyenya igneous complex, northwestern Namibia: constraints on the composition...Energy, Geological Survey. P.O. Box 2168. Windhoek, Namibia Received 24 August 1995; accepted 22 March 1996...intrusive rocks from the Mesozoic age Okenyenya igneous complex, which is temporally and spatially associated...rocks in northwestern Namibia. On the basis of bulk rock geochemistry the Okenyenya intrusions can be subdivided...The range in isotope composition shown by the Okenyenya intrusions is similar to that shown by the Etendeka |  | | Journal (article/letter/editorial) | | of the Alkaline Core of the Messum Igneous Complex, Namibia: Evidence for the Progressively Decreasing...3 GEOLOGICAL SURVEY, P.O. BOX 2168, WINDHOEK, NAMIBIA RECEIVED NOVEMBER 12, 1998; REVISED TYPESCRIPT...TYPESCRIPT ACCEPTED APRIL 12, 1999 The Messum complex of NW Namibia, a part of the Paraná– Etendeka volcanic...into (1) a sub-alkaline suite, (2) an outer quartz syenite suite, and (3) an inner silicaundersaturated...dominated by nepheline syenite. Compositional differences within the quartz syenite suite can be explained |  | | Journal (article/letter/editorial) | | Damaraland Lamprophyres and Carbonatites, Northwestern Namibia: Evidence for Plume–Lithosphere Interactions ANTON...igneous complexes in Damaraland, northwestern Namibia. Lamprophyres, emplaced as late-stage dykes, stocks...WORDS: geochemistry; lamprophyre carbonatite; Namibia; Tristan plume ∗Corresponding author. Telephone:+27-21-650-2921...complexes extend through Damaraland in northwestern Namibia (Fig. 1) and provide an example of the contiguous... 1. Simplified geological map of northwestern Namibia, showing the main outcrop regions of the Etendeka |  | Cernuschi, F., Dilles, J.H., Kent, A.J.R., Schroer, G., Raab, A.K., Conti, B., Muzio, R. (2015) Geology, geochemistry and geochronology of the Cretaceous Lascano East intrusive complex and magmatic evolution of the Laguna Merín basin, Uruguay. Gondwana Research, 28 (2) 837-857 doi:10.1016/j.gr.2014.07.007 | Journal (article/letter/editorial) | | geochronology of the Cretaceous Lascano East intrusive complex and magmatic evolution of the Laguna Merı́n basin...geochronology of the Cretaceous Lascano East intrusive complex and magmatic evolution of the Laguna Merı́n basin...the Cretaceous Lascano East intrusive RI P T complex and magmatic evolution of the Laguna Merín basin...alkaline compositions are well-exposed and studied in Namibia on the African margin. Ring complexes CE are...basalts and the sub-alkaline to alkaline ring complex centers within the evolving rifted continental |  | | Journal (issue) | | island. The eontribution of Birkenmajer deseribes a region not very familiar in literature. He gives a review...transmission of seismic energy through the tectonically complex overlying section (Fig. 3). 239 100 km Basel...ofIvrea (crossed ruling); CRL = Cremosina line complex, bounding the Ivrea-Ceneri body (narrow horizontal...Helvetic nappes and the External Massifs is similarly complex, yet did not produce a comparable effect, and that...Scientific Party, 1991; Buness, 1992). The border region of the Po plain is problematic. Here, excellent |  | | Book | | section of certain key indicator minerals – such as quartz, olivine, nepheline, aegirine–augite – provides...simplest way to visualize the chemical composition of complex silicate materials is as a mixture of oxides: silicon...used in rock classification is the presence of quartz or nepheline in the rock, indicating whether it...or absence of quartz); • quantitative petrographic data (e.g. the percentage of quartz in the rock);...igneous rock Felsic = light-coloured minerals Quartz Feldspars Plagioclase Alkali feldspar Feldspathoids |
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