Rondeau, Benjamin; Cenki-Tok, Bénédicte; Fritsch, Emmanuel; Mazzero, Francesco; Gauthier, Jean-Pierre; Bodeur, Yves; Bekele, Eyassu; Gaillou, Eloïse; Ayalew, Dereje
(2012)
Gem opals from Wegel Tena, Wollo Province, Ethiopia, occur in Oligocene rhyolitic ignimbrites. They display a unique geochemistry, with some samples yielding the highest Ba concentrations ever recorded. They are generally ...