Insights into the geology of the Cyclades, Greece: an excursion to the island of Tinos

The Attic-Cycladic Crystalline Belt in the central Aegean region represents an important tectono-stratigraphic unit of the Hellenides, illustrating many aspects of subduction zone processes and the exhumation of high-pressure/low-temperature (HP/LT) rocks. Many of its main features can be studied excellently on the island of Tinos. The five-day excursion presented here provides an overview of the principal geological, magmatic, and tectonic-metamorphic relationships on this island and introduces characteristic features of the regional geology. The main topics are (a) the structural architecture of Tinos, which comprises at least three tectonic subunits with different geological and metamorphic histories, (b) the metamorphic conditions in the various subunits, which include a variety of different P–T regimes (amphibolite facies, greenschist facies, eclogite to epidote-blueschist facies, contact metamorphism) and the associated ages, (c) the origin and significance of block-in-matrix structures in the marbleschist sequences that dominate most of the island, (d) the main features of a Jurassic ophiolite, (e) the formation of ophicalcite and listvenite, (f) the intrusion of Miocene granitoids (I- and S-type), and (g) mining activities. The excursion is based on a field course that was regularly held as part of the MSc program in Geosciences at the University of Münster.