title: Archaean zircons in Miocene oceanic hotspot rocks establish ancient continental crust beneath Mauritius.
abstract: A fragment of continental crust has been postulated to underlie the young plume-related lavas of the Indian Ocean island of Mauritius based on the recovery of Proterozoic zircons from basaltic beach sands. Here we document the first U-Pb zircon ages recovered directly from 5.7 Ma Mauritian trachytic rocks. We identified concordant Archaean xenocrystic zircons ranging in age between 2.5 and 3.0 Ga within a trachyte plug that crosscuts Older Series plume-related basalts of Mauritius. Our results demonstrate the existence of ancient continental crust beneath Mauritius; based on the entire spectrum of U-Pb ages for old Mauritian zircons, we demonstrate that this ancient crust is of central-east Madagascar affinity, which is presently located ∼700 km west of Mauritius. This makes possible a detailed reconstruction of Mauritius and other Mauritian continental fragments, which once formed part of the ancient nucleus of Madagascar and southern India.
authors.affiliation: School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg 2050, South Africa.
authors.forename: Lewis D
authors.initials: LD
authors.lastname: Ashwal
authors.affiliation: School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg 2050, South Africa.|Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, D14473 Potsdam, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Wiedenbeck
authors.affiliation: School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg 2050, South Africa.|Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, D14473 Potsdam, Germany.|Center for Earth Evolution and Dynamics (CEED), University of Oslo, 0316 Oslo, Norway.|Geodynamics, Norges Geologiske Undersøkelse (NGU), N-7491 Trondheim, Norway.
authors.forename: Trond H
authors.initials: TH
authors.lastname: Torsvik