Geochemistry and Petrogenesis of the Late Archaean High-K Granites in the Southern Musoma-Mara Greenstone Belt: Their Influence in Evolution of Archaean Tanzania Craton

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dc.creatorMshiu, Elisante E.
dc.creatorMaboko, Makenya A. H.
dc.date2016-09-21T12:00:58Z
dc.date2016-09-21T12:00:58Z
dc.date2012
dc.date.accessioned2018-03-27T08:57:29Z
dc.date.available2018-03-27T08:57:29Z
dc.descriptionFull text can be accessed at http://www.sciencedirect.com/science/article/pii/S1464343X12000386
dc.descriptionMusoma-Mara Greenstone Belt (MMGB) is abundantly occupied by the post-orogenic high-K granites which also they mark the end of magmatism in the area. The granites are characterized by high SiO2 and Al2O3 contents that average 74.42% and 13.08% by weight respectively. They have low Na2O content (mean = 3.36 wt.%) and high K2O contents (mean = 4.95 wt.%) which resulted to relatively high K2O/Na2O ratios (mean = 1.50). They also characterized by low Mg# (mean = 33) as well as low contents of transition elements such as Cr and Ni which are below detection limit (<20 ppm). Negative anomalies in Eu (Eu/Eu*, mean = 0.56), Nd, Ta and Ti elements as shown in the chondrite and primitive mantle normalized diagrams indicate MMGB high-K granites originated from a subduction related environments. These high-K granites also characterized by relative enrichment of the LREE compared to HREE as revealed by their high (La/Yb)CN ratio ranging from 8.71 to 50.93 (mean = 26.32). They have relatively flat HREE pattern with (Tb/Yb)CN ratio varying between 0.81 and 2.12 (mean = 1.55). Their linear trend in the variation diagrams of both major and trace elements indicate magmatic differentiation was also an important process during their formation. Conclusively, the geochemical characteristics as well as experimental evidences suggests MMGB high-K granites were formed from partial melting of pre-existing TTG rocks, under low pressure at 15 km depth or less and temperature around 950 °C in which plagioclase minerals were the stable phases in the melt.
dc.identifierMshiu, E.E. and Maboko, M.A., 2012. Geochemistry and petrogenesis of the late Archaean high-K granites in the southern Musoma-Mara Greenstone Belt: Their influence in evolution of Archaean Tanzania Craton. Journal of African Earth Sciences, 66, pp.1-12.
dc.identifierhttp://hdl.handle.net/20.500.11810/3773
dc.identifier10.1016/j.jafrearsci.2012.03.002
dc.identifier.urihttp://hdl.handle.net/20.500.11810/3773
dc.languageen
dc.publisherElsevier
dc.subjectGeochemistry
dc.subjectPetrogenesis
dc.subjectHigh-K granites
dc.subjectMusoma-Mara Greenstone Belt
dc.subjectArchaean Tanzania Craton
dc.titleGeochemistry and Petrogenesis of the Late Archaean High-K Granites in the Southern Musoma-Mara Greenstone Belt: Their Influence in Evolution of Archaean Tanzania Craton
dc.typeJournal Article, Peer Reviewed

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