Srinath Krishnan (a), Matthew Huber (b) & Mark Pagani (a)
(a) Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, Connecticut 06520, USA. E-mail: srinath.krishnan@yale.edu
(b) Institute for the Study of Earth, Oceans, and Space, Morse Hall, University of New Hampshire, 8 College Road, Durham, NH 03824-3525, USA.