Detailed mapping and structural observations on the Cycladic Blueschist Unit (CBU) on Iraklia Island integrated with detrital zircon (DZ) U-Pb ages elucidate the Mesozoic pre-subduction and the Cenozoic orogenic evolution. Iraklia tectonostratigraphy includes a heterogeneous Lower Schist Fm., juxtaposed against a Marble Fm. and an overlying Upper Schist Fm. The contact is an extensional ductile-to-brittle-ductile, top-to-N shear zone, kinematically associated with the Oligo-Miocene exhumation. The DZ spectra of the Lower Schist have Gondwanan/peri-Gondwanan provenance signatures and point to Late Triassic Maximum Depositional Ages (MDAs). A quartz-rich schist lens yielded Precambrian DZ ages exclusively and is interpreted as part of the pre-Variscan metasedimentary Cycladic Basement, equivalent to schists of the Ios Island core. The Upper Schist represents a distinctly different stratigraphic package with late Cretaceous MDAs and dominance of Late Paleozoic DZ ages, suggestive of a more internal Pelagonian source. The contrast in the DZ U-Pb record between Lower and Upper Schist likely reflects the difference between a Paleotethyan and Neotethyan geodynamic imprint. The Triassic DZ input from eroded volcanic material is related to the final Paleotethys closure and Pindos/CBU rift basin opening, while late Cretaceous metamorphic/magmatic zircons and ~48–56 Ma zircon rims constrain the onset of Neotethyan convergence and high-pressure subduction metamorphism.

This manuscript presents a multidisciplinary study that proposes a methodology for delineating and categorizing vulnerability at rockfall risk areas to avoid human injuries and infrastructure damage caused by rockfalls. The presented workflow includes (i) classical geological mapping, (ii) the interpretation of high-resolution satellite data for observing the spatial distribution of fallen boulders, (iii) analytical hierarchy processing of spatial information within a Geographical Information System (GIS) platform, (iv) close-range remote sensing campaigns with Unmanned Aerial Systems (UASs), and (v) integrated simulation of rockfall events. This methodology was applied to Kalymnos Island, which belongs to the Dodecanese Islands complex of the southeastern Aegean Sea in Greece. It is characterized by unique geomorphological features, including extensive vertical limestone cliffs that span the island. These cliffs make it one of the world’s most densely concentrated areas for sport climbing. The results highlighted the areas that the local authorities need to focus on and suggested measures for increasing the safety of climbers and infrastructure.