Table Of Content

mbri eseart > y) http://www.elsevier.com/locate/precamres ELSEVIER Volumes 204-205 CONTENTS May 2012 (Abstracts/contents lists published in Am. Geol. Inst. Bibliogr.; Abstr. Bull. Signaletique; Chem. Abstr.; Curr. Contents; Phys Chem. Earth Sci., Geo Abstr.; Mineral Abstr.) U-Pb dating and Sm-Nd isotopic analysis of granitic rocks from the Tiris Complex: New constaints on key events in the evolution of the Reguibat Shield, Mauritania D.1. Schofield, M.S.A. Horstwood, PE.J. Pitfield, M. Gillespie, F Darbyshire, E.A. O'Connor andT.B. Abdouloye ... Revised Eburnean geodynamic evolution of the gold-rich southern Ashanti Belt, Ghana, with new field and geophysical evidence of pre-Tarkwaian deformations S. Perrouty, L. Ailleres, M.W. Jessell, L. Baratoux, Y.B ourassa and B. Crawford Dating the Itabira iron formation, Quadrilatero Ferrifero of Minas Gerais, Brazil, at 2.65 Ga: Depositional U-Pb age of zircon from a metavolcanic layer A.R. Cabral, A. Zeh, N. Koglin, A.A. Seabra Gomes, D.J. Viana and B. Lehmann U-Pb and Hf isotope record of detrital zircons from gold-bearing sediments of the Pietersburg Greenstone Belt (South Africa)-ls there a common provenance with the Witwatersrand Basin? A. Zeh and A. Gerdes Constraining the timing and provenance of the Neoproterozoic Little Willow and Big Cottonwood Formations, Utah: Expanding the sedimentary record for early rifting of Rodinia C.J. Spencer, C.W. Hoiland, R.A. Harris, PK. Link and E.A. Balgord New SHRIMP U-Pb zircon ages from the Hartswater Group, South Africa: Implications for correlations of the Neoarchean Ventersdorp Supergroup on the Kaapvaal craton and with the Fortescue Group on the Pilbara craton M.O. de Kock, N.J. Beukes and R.A. Armstrong Neoproterozoic and Palaeozoic evolution of SW Scandinavia based on integrated seismic interpretation A. Lassen and H. Thybo CAPTION FOR COVER PHOTOGRAPH 3,243 million-year-old spherules in the Fig Tree Group, Barberton Greenstone Belt, South Africa, formed as a result of large meteorite impacts on the early Earth. The 35-cm-thick spherule bed (S3) is composed of nearly pure spherules produced during the condensation of an impact-produced rock vapor cloud. The estimated diameter of the bolide was 20-50 km. The spherules, 0.5-1.5 mm in diameter in the photo, include silica-(clear), phyllosilicate- (gray), and rutile/anatase-rich (black) varieties; massive and layered types; and a few originally hollow spherules. This is one of four spherule layers in the Barderton Belt, ranging from 3,470-3,243 Ma, that represent the oldest known impact deposits and provide direct evidence for a significant flux of large impactors as late as 3.2 Ga. Photograph: D.R. Lowe Available online at www.sciencedirect.com AM | SciVerse ScienceDirect