O EOL GIC G A D D A E D C E I H C I L E O S F u n 2 d 6 la serena octubre 2015 ada en 19 Detrital zircon geochronology of Palaeozoic siliciclastic rocks from the Ellsworth Mountains, West Antarctica Paula Castillo* and C. Mark Fanning Research School of Earth Sciences, The Australian National University, Canberra, Australia. Rodrigo Fernández University of Texas Institute for Geophysics, The University of Texas at Austin, Austin, Texas, USA. Fernando Poblete Geosciences Rennes, Université de Rennes 1, Rennes, France. Departamento de Geología, Universidad de Chile, Santiago, Chile. *Contact email:
[email protected] Abstract. In the Ellsworth Mountains there is an extensive record of sedimentation from early Cambrian to Permian times. However, the tectonic history and the palaeogeographic significance remain enigmatic. Nine sandstone samples were analysed for their U-Pb detrital zircon age spectra using SHRIMPII and RG. They belong to the early Cambrian to Carboniferous-Permian sequences and record typical Gondwana margin signatures. Variations up section/sequence in zircon provenance suggest restricted basinal deposition during the Cambrian,! with likely sources in the Namaqua-Natal and Mozambique/Maud Belts. There are little or no contributions from older cratons and so the Ellsworth basin evolved as a separate basin to that in the Transantarctic Mountains.! This basin configuration changed after the Devonian and deposition continued Figure 1. Reconstruction of part of Gondwana at ca. 500 Ma. during the late Palaeozoic, when the Ellsworth Mountains South America: SFC - Sao Francisco craton; PPC - basin only received detritus from the Ross/Pan-African Paranapanema craton; RPC - Río de la Plata craton.