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Neoproterozoic magmatic evolution of the southern Ouaddaï Massif (Chad)

Djerossem, Félix; Berger, Julien; Vanderhaeghe, Olivier; Isseini, Moussa; Ganne, Jérôme; Zeh, Armin

Abstract:
This paper presents new petrological, geochemical, isotopic (Nd) and geochronological data on magmatic rocks from the poorly known southern Ouaddaï massif, located at the southern edge of the so-called Saharan metacraton. This area is made of greenschist to amphibolite facies metasediments intruded by large pre- to syn-tectonic batholiths of leucogranites and an association of monzonite, granodiorite and biotite granite forming a late tectonic high-K calc-alkaline suite. U-Pb zircon dating yields ages of 635 ± 3 Ma and 613 ± 8 Ma on a peraluminous biotite-leucogranite (containing numerous inherited Archean and Paleoproterozoic zircon cores) and a muscovite-leucogranite, respectively. Geochemical fingerprints are very similar to some evolved Himalayan leucogranites suggesting their parental magmas were formed after muscovite and biotite dehydration melting of metasedimentary rocks. A biotite-granite sample belonging to the late tectonic high-K to shoshonitic suite contains zircon rims that yield an age of 540 ± 5 Ma with concordant inherited cores crystallized around 1050 Ma. Given the high-Mg# (59) andesitic composition of the intermediate pyroxene-monzonite, the very similar trace-element signature between the different rock types and the unradiogenic isotopic signature for Nd, the late-kinematic high-K to shoshonitic rocks formed after melting of the enriched mantle and further differentiation in the crust. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000129747
Veröffentlicht am 16.02.2021
Originalveröffentlichung
DOI: 10.1051/bsgf/2020032
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Dimensions
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 1777-5817
KITopen-ID: 1000129747
Erschienen in Bulletin de la Société Géologique de France
Verlag EDP Open
Band 191
Seiten 34
Vorab online veröffentlicht am 24.11.2020
Nachgewiesen in Scopus
Web of Science
Dimensions
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