Blocks of Messinian gypsum in western Sicily

From 2009-2012, graduate student Ryan Thress investigated blocks of upper Miocene gypsum in the western Caltanisseta Basin in west-central Sicily. My UW colleague Prof. Charlotte Schreiber co-supervised Ryan's research, which we undertook in collaboration with our Italian colleagues Prof. Stefano Lugli in Modena and Dr. Vinizio Manzi in Parma. In his Master's thesis, "Submarine collapse of an evaporite platform during the Messinian Salinity Crisis: dimensional and spatial patterns of rafted blocks," Ryan used his field work, interpretations of satellite imagery, and shape analysis to infer that this block-in-matrix facies was deposited in the Messinian foredeep as debris flows that originated by the collapse of a wedge-top evaporite platform. See his AGU 2012 poster for details and analysis.

Photo A by Ryan is Monte Banco, near Raffadali, showing ten cycles of Messinan gypsum in a single block. Scale: notice the small stone house, about 3 m high, circled in lower left corner. Cycles identified in Roveri et al., (2006, Acta Naturalia de l'Ateneo Parmense). Photo B by C. Schreiber looking east at the landscape north of Siculiana. Individual blocks of gypsum marked by arrows. Click on the photos for larger images.