1. G. H. Miller and B. J. Johnson, Center for Geochronical Research, Institute of Arctic and Alpine Research (INSTAAR), and Department of Geological Sciences, University of Colorado, Boulder, CO 80309–0450, USA. J. W. Magee, Department of Geology, Australian National University, Canberra ACT 0200, Australia. M. L. Fogel, Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, USA. N. A. Spooner, M. T. McCulloch, L. K. Ayliffe, Research School of...