Fig. 1From: Preface: clay mineral diagenesis and very low-grade metamorphic processes. Proceedings of the 2011 Frey–Kübler symposiumBernard Kübler in 1991 (with yellow cap) visiting a piemontite-schist quarry on the South Island of New Zealand during the IGCP project 294 excursion. Photograph by Rafael Ferreiro MählmannBack to article page