Professor emeritus, Rice University

Retired/consultant

Sorbonne University, Paris, and George Mason University, Fairfax Va USA

Libya, Zawia university

Professor of Geology, University of Cincinnati

Professor, Department of Geological Sciences, University of Saskatchewan

Colorado School of Mines

Victoria University of Wellington

Professor of Sedimentology, Facultad de Ciencias Naturales y Museo, University of La Plata

University of Kansas, Department of Geology