The island of Patmos is situated in the southern Aegean Sea (Greece), just north of the present locus of active volcanism. The island is almost entirely built up of volcanic rocks that are 6.6 to 5.2 million years old. We obtain these ages with ⁴⁰Ar / ³⁹Ar dating technique on sanidine and biotite minerals. Our new age data indicate a geologically brief volcanic period (lasting less than 1.5 million years) that can be divided into three volcanic intervals and correlated to tectonics.

About 2 million years ago, rich gold deposits formed at Martabe, on the island of Sumatra in Indonesia. Fluids may have moved as the result of fault dilation caused by changes in stress orientation during the earthquake cycle, so to work out exactly when and how long between cycles, we dated a potassium-bearing mineral, alunite, using argon geochronology in association with diffusion experiments during temperature-controlled furnace step-heating, showing two episodes 250 thousand years apart.

Dating low-grade metamorphic rocks with the ⁴⁰Ar / ³⁹Ar method is difficult because samples are fine-grained mixtures between detrital and newly grown metamorphic minerals. We use a careful step-heating schedule and resolve limits within the complex age spectra thus derived to infer the timing of metamorphism and deformation in the Delamerian Orogen (formerly part of eastern Gondwana). Results suggest detrital mineral from up to 1172 Ma and that metamorphic minerals grew at 470–458 Ma.

This research is part of a PhD thesis examining evaporite detachments characteristics. ⁴⁰Ar/³⁹Ar geochronology is employed to constrain the timing of formation and deformation events. A diagenetic age of ~514 Ma is interpreted from the oldest significant step age. Other step ages may represent a Cambrian–Permian deformation event or a complex mixing age of diagenetic Ar with partially reset Ar during the Cenozoic. We report the first closure temperature for polyhalite between 254 and 277 °C.

High-resolution geochronology is one of the key factors to predict volcanic eruptions. To build up a high-resolution geochronological framework, we reported 21 new high-precision eruption ages (⁴⁰Ar / ³⁹Ar) for a ~ 3.3 × 10⁶-year-old volcanic field: Milos (Greece). In combination with geochemical information and eruption volumes from the volcanoes of Milos, the long-lived volcanic history could provide important clues for the prediction of volcanic eruptions.