Electron microprobe (EPMA) monazite Th–U – Pb ages have been determined from a suite of granulite and granitoids rocks of the Sangmelima granite-greenstone Belt (SGB) of the Ntem Complex in Cameroon or NW Congo Craton.The monazite-bearing rocks include charnockitic gneiss, migmatitic tonalite-trondhjemite-granodiorite (TTG) gneisses, granodiorite, monzogranite and a late pegmatite …
2004-6-30 · This process is important both in volcanic-arc (e.g. Hyndman and Foster, 1988) and in extensional setting (e.g. Bergantz, 1989). Structural investigations indicated that the Mitwaba area was undergoing compressional tectonics (D 1 ) during the emplacement of the S-type granitoids and thus cannot mark an extensional regime.
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2017-8-23 · The metasedimentary rocks and granites of the Damara Orogen - a fold belt which extends across northern Namibia between the ancient landmasses of the Congo and Kalahari Cratons - illustrate the immense forces that over millions of years shaped the face of planet Earth. According to the theory of plate tectonics, the crust, which represents
2009-10-21 · 2009-10-21 · bearing greisen. The Spitzkoppe granites are highly evolved, marginally peraluminous (A/CNK 0.95 to 1.09) and characterized by high SiO 2 (74.4 to 78.6 wt.%), Na 2O+K 2O (7.6 to 8.8 wt.%, with K 2O prevailing over Na 2O), F, Rb, and Ga, as well as low MgO, Ba, and Sr. The small but clear differences in REE patterns [(La/Yb)
2010-4-1 · 2010-4-1 · The Eastern Congo—a beauty spot, rediscovered from a geological point of view The Eastern Congo—a beauty spot, rediscovered from a geological point of view , F.U.; Glasmacher, U.A.; Malikwisha, M.; Mambo, V.S.; Mutete, B.V. 2010-04-01 00:00:00 The aim of our research is to unravel the evolution of a bizarre high mountain range, located in the East African …
across Namibia between the Kalahari and Congo granites, while the broader leucosomes may represent cratons (see inset of Fig.1). Pre-Damaran basement is intrusive melts from deeper levels. To the north, the exposed at the northern and southern margins and in regional fabric within the migmatites is progressively several inliers within the belt.
2017-6-5 · The process that leads to the formation of all these cumulate rocks is most likely to be filter pressing during flattening deformation, leaving the rocks depleted in quartz and sodic plagioclase and enriched in garnet and K-feldspar—as reflected in positive Eu anomalies and enrichment in Ba, Pb, and both Y and Yb for the garnet-bearing cumulates.
2009-4-1 · This study presents U–Pb, Hf-isotope and trace-element data on zircons separated from heavy-mineral concentrates collected in several drainages during a diamond exploration campaign in the Luebo district (Fig. 2a and b) situated in the central part of the Congo-Kasai Craton in the Democratic Republic of the Congo (hereafter referred to as Congo). These data provide insights into the …
The grey granites are composed of quartz, plagioclase, alkali feldspar (microcline/orthoclase) and biotite. Allanite, apatite and zircon occur as accessory phases. Minor muscovite occurs as an alteration product of K-feldspar. In general, the grey granites have a medium grain size except for some alkali feldspar
2000-1-1 · This indicates that there must have been a mineral 144 Journal of African Earth Sciences Neoarchaean crustal evolution in the Congo Craton in the source of the granites that fractionated the TTG suite. The melts were generated at the current 147Sm/l~Nd of the potential source rocks, which have exposure level or slightly deeper crustal levels.
2009-4-1 · The Luebo district is situated within the Congo-Kasai Craton (Fig. 1, Fig. 2a), which extends southward into Angola and northward into the Central African Republic, Gabon and Cameroon.However, correlations between the southern part of the Congo-Kasai Craton (Angola and Congo) and the northern extension are hampered by thick Phanerozoic cover.
2003; McDermott et al., 1996), (ii) syn-orogenic S-type granites formed by partial melting of upper crustal meta-sedimentary rocks (Jung et al., 2000; McDermott et al., 1996) and (iii) late-orogenic A-type granites (Jung et al., 2000). The exact geodynamic process that caused heat transfer and melting during collision of …
2021-6-15 · The geology of many Neoarchean terranes in North and South America, Australia, China, India, and East Africa have been studied in detail, whereas the approximately 80,000 km 2 of Archean rocks in the northeast Democratic Republic of Congo (DRC) are amongst the least known Archean rocks in the world. Limited reconnaissance Rb-Sr dating (Cahen et al., 1984, Poidevin, 1985) implies much …
2017-8-23 · CONGO. The metasedimentary rocks and granites of the Damara Orogen - a fold belt which extends across northern Namibia between the ancient landmasses of the Congo and Kalahari Cratons - illustrate the immense forces that over millions of years shaped the face of planet Earth. According to the theory of plate tectonics, the crust, which represents ...
A Congo Craton source is likely, in particular if we consider that the southern Ouaddaï is part of the Central Africa Orogenic Belt, which obviously formed a basin above thinned continental (?) crust between the Congo and the Saharan Metacraton, prior to intrusion of the pre-tectonic granites at ca. 640 Ma (Djerossem et al., 2020).
2013-9-1 · The Swakop River exposes a unique structural section into the root of the Pan-African Damara orogenic belt (DOB) in Namibia formed as a result of collision between the Congo and the Kalahari cratons from ca. 550 to 500 Ma.The Central Zone of the Damara orogenic belt is characterized by amphibolite to granulite facies metamorphism accompanied by intense partial melting.
The present study verifies that the 2.32 to 2.29 Ga high-K granites did occur along the southern margin of the NCC, filling in the early Paleoproterozoic magmatic gap. (2) The high-K granites show features transitional between S-type and normal A- and I-type granites, and might be recycling of metapsammite-dominated sources. (3)
Kinematic evolution of the Araçuaí-West Congo orogen in Brazil and Africa: Nutcracker tectonics during the Neoproterozoic assembly of Gondwana. Fernando F. Alkmim, Stephen Marshak, Antônio Carlos Pedrosa-Soares, Guilherme Gravina Peres, Simone Cerqueira Pereira Cruz, Alan Whittington.
2013-9-1 · The Swakop River exposes a unique structural section into the root of the Pan-African Damara orogenic belt (DOB) in Namibia formed as a result of collision between the Congo and the Kalahari cratons from ca. 550 to 500 Ma. The Central Zone of the Damara orogenic belt is characterized by amphibolite to granulite facies metamorphism accompanied by intense partial melting.