[1] Univ Atlant, Fac Ciencias Bas, Programa Fis, Km 7 Antigua via Puerto Colombia, Barranquilla, Atlantico, Colombia
[2] Univ Bari Aldo Moro, Dipartimento Sci Terra & Geoambientali, Via Orabona 4, Bari, Italy
[3] Grand Valley State Univ, Dept Geol, Padnos Hall Sci, Allendale, MI USA