Today, we visited a gypsum quarry in Calatafimi. It is a working quarry, but the owner, Ing. Brescia, was gracious enough to let us look at the quarry walls. The quarry rocks date to the Messinian, a time period about five million years ago. During this time the Straight of Gibraltar was closed and the Mediterranean was closed off from the remainder of the worlds oceans. The hot climate caused water to evaporate and the salinity of the sea water to become dramatically higher than it is today. As the sea water evaporated, the gypsum precipitated out and formed the crystals we can see in the quarry today. It takes a kilometer of sea water to create 14 meters of rock through evaporation.
Working in the quarry was a great treat as many of us had never seen gypsum out of the classroom and the thickness of the rocks as well as the beautiful crystals even amazed the professors.
Our project at the quarry was to describe the layers of rocks in the quarry, and to try to decide what environment was when they formed. Remains of bacteria within the crystals indicate the rocks formed in a shallow environment.
After our field work was done, we were surprised by a lovely treat of an extensive variety of pastries and cool drinks.
Thank you to Ing. Brescia and Signore Mancuso and the rest of the quarry staff for allowing us to join you for the morning.
