title: Building Archean cratons from Hadean mafic crust.
abstract: Geologic processing of Earth's surface has removed most of the evidence concerning the nature of Earth's first crust. One region of ancient crust is the Hudson Bay terrane of northeastern Canada, which is mainly composed of Neoarchean felsic crust and forms the nucleus of the Northeastern Superior Province. New data show these ~2.7-billion-year-old rocks to be the youngest to yield variability in neodymium-142 (142Nd), the decay product of short-lived samarium-146 (146Sm). Combined146-147Sm-142-143Nd data reveal that this large block of Archean crust formed by reworking of much older (>4.2 billion-year-old) mafic crust over a 1.5-billion-year interval of early Earth history. Thus, unlike on modern Earth, mafic crust apparently could survive for more than 1 billion years to form an important source rock for Archean crustal genesis.
authors.affiliation: Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada. jonathan.oneil@uottawa.ca.
authors.forename: Jonathan
authors.identifier: 0000-0002-9869-6661
authors.initials: J
authors.lastname: O'Neil
authors.affiliation: Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015, USA.
authors.forename: Richard W
authors.identifier: 0000-0001-7195-2074
authors.initials: RW
authors.lastname: Carlson