Lineke Woelders (a), Robert Speijer (a) & Philippe Claeys (b)
(a) Department of Earth and Environmental Sciences, Division of Geology, KU Leuven, Celestijnenlaan 200E, B-3001 Leuven-Heverlee, Belgium. E-mail: lineke.woelders@ees.kuleuven.be
(b) Department Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.