The Uppermost Unit of Crete is attributed to the Internal Hellenides and consists of different nappes derived from an Upper Cretaceous arc (Asterrousia), and a late Jurassic to Cretaceous subduction-accretion complex (Vatos, Arvi, Miamoux).
Blueschists of the subduction-accretion complex of central Crete (Preveli nappe, T = ca. 350°C, P= ca. 1.2 GPa) are resting on top of Pindos rocks and are overlain by Cretaceous Vatos flysch, Jurassic ophiolites and a second sequence of blueschist-facies rocks referred to as Mourne nappe.
The Mourne blueschists show a large variety of amphiboles, such as glaucophane, riebeckite, richterite, ferri-winchite, barroisite, magnesio-hornblende, edenite and actinolite. K-Ar dating of barroisite and phengite yielded late Jurassic ages (Seidel et al., 1977).
Top-to-the SW shearing under epidote blueschist-facies conditions led to the dominant foliation of the Mourne metabasites, which is characterized by the shape-preferred orientation of blue amphibole, omphacite (as relics), epidote, rutile and titanite.
Growth of barroisite, magnesio-hornblende and epidote indicate isothermal decompression under epidote-amphibolite facies conditions.
Cooling and further decompression is indicated by several generations of younger veins mineralized with albite, quartz, epidote, actinolite (greenschist facies) and actinolite, epidote, prehnite, calcite (prehnite-actinolite facies).
The youngest deformation led to discrete foliation-parallel shear zones under brittle conditions, related to the emplacement of the Mourne nappe on top of the ophiolites.
Funding by DFG (Zu 73-34) is gratefully acknowledged.
Seidel E et al (1977) Metamorphic rocks of late Jurassic age as components of the ophiolitic mélange on Gavdos and Crete (Greece). Geol. Jb. 28:3–21