Mark Wilson June 7th, 2013
MARSALA, SICILY, ITALY–This morning the pre-conference field trip of the International Bryozoology Association headed into the mountains of central Sicily. The roads were steep and windy, as one would imagine, and the views of mountainsides, villages and fields spectacular. We were high enough to be in some small woods and scrub forests. Our goal was to see some mysterious blocks of Permian limestone seemingly out of place on an island dominated by Cenozoic sediments.
We met a team of friendly geologists from the University of Palermo in the Sosio Valley near Palazzo Adriano. They were well prepared to tell a complicated story of tectonics in the classic geological manner: maps and charts held by students as a professor lectures. It was very effective, aided by the superb weather and amazing views.
In this geological cross-section, the Permian rocks are shown as blue. Already you see something odd with the same color of rock above and below the blue, showing that it is tectonically bounded. It is part of a melange (in the geological sense) of blocks of rock broken and thrust about during the tectonism of the Miocene. The Permian rock was recognized as such by its fossil content, which includes distinctive conodonts, fusulinids, brachiopods, bryozoans and corals. It sits surrounded by much younger Miocene sediments, demonstrating the complex tectonics leading to this unusual setting.
Above is the Permian outcrop in the Sosio Valley. It stands out as very different from its surroundings by its lithology alone. I admire the geologists, though, who found diagnostic fossils within it — I saw just a very few highly recrystallized fusulinids and corals.
For lunch we went to the city museum in Palazzo Adriano and had delicious sandwiches and cakes. There we saw some of the best fossils from the Permian outcrops on display.
This is one of the churches in Palazzo Adriano on the city square. It looks to be neglected on the exterior, but inside …
… it is elaborate and well-maintained.