Shrimp U–Pb zircon age evidence for Paleoproterozoic sedimentation and 2.05 Ga syntectonic plutonism in the Nyong Group, South-Western Cameroon: consequences for the Eburnean–Transamazonian belt of NE Brazil and Central Africa
作者： Cathérine Lerouge , Alain Cocherie , Sadrack F Toteu , Joseph Penaye , Jean-Pierre Milési
DOI: 10.1016/J.JAFREARSCI.2005.11.010
关键词: Craton 、 Provenance 、 Metasedimentary rock 、 Geology 、 Gneiss 、 Geochemistry 、 Charnockite 、 Archean 、 Plutonism 、 Zircon
摘要: Abstract The Nyong Group of the NW corner Congo craton is a metasedimentary and metaplutonic rock unit that underwent high-grade tectono-metamorphic event at ∼2050 Ma associated with charnockite formation. However, age sedimentation plutonism was not known. In view this, considered to be part Archean reactivated during Paleoproterozoic or Pan-African orogeny. Such interpretation widely supported by persistence inheritance revealed Nd isotope data on whole rocks U–Pb zircons. New SHRIMP analyses detrital zircons from metasediments (BIF, orthopyroxene gneiss garnet gneiss) yield Mesoarchean ages, youngest zircon 2423 ± 4 Ma, thus giving maximum deposition for Group. Data metagranodiorite Bonguen metasyenite Lolodorf emplacement ages 2066 ± 4 Ma 2055 ± 5 Ma respectively, (2836 ± 11 Ma) metasyenite. syntectonic these plutonic 2044 ± 9 Ma obtained Bienkop charnockite, Eburnean metamorphism which continued probably up 1985 ± 8 Ma. These new permit correlation NE Brazil discussion source provenance detritus Finally, it proposed West Central African Belt (WCAB) in southern Cameroon, Gabon, Angola represents segment Eburnean–Transamazonian orogeny resulted convergence collision between Sao Francisco-Nigerian Shield block former megacraton.
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