Detrital blue amphiboles from the western Othrys Mountain and their relationship to the blueschist terrains of the Hellenides (Greece)

In contrast to blue amphiboles of the Ossa and Olympos tectonic windows in Thessaly, detrital blue amphiboles in Paleocene flysch deposits in the western Othrys Mountain (Pelagonian Zone s.l.) are chemically comparable with blue amphiboles from the Cyclades. For the detrital material, therefore, a source with "Cycladic" chemical affinities is assumed. The occurrence of these detrital minerals is in line with a Cretaceous onset of blueschist facies metamorphism in parts of the Hellenides, especially in the Cycladic belt. This was in response to Cretaceous subduction of the Pindos oceanic plate along the external margin of the Pelagonian micro-continent. Blueschist complexes were exhumed latest in the Paleocene when the terrigenous flysch sedimentation started in the Pelagonian and Pindos zones.     

Evaluating and comparing Sentinel 2A and Landsat-8 Operational Land Imager (OLI) spectral indices for estimating fire severity in a Mediterranean pine ecosystem of Greece

The main purpose of this study is to explore the relationship between three field-based fire severity indices (Composite Burn Index-CBI, Geometrically structure CBI, weighted CBI) and spectral indices derived from Sentinel 2A and Landsat-8 OLI imagery on a recent large fire in Thasos, Greece. We employed remotely sensed indices previously used from the remote sensing fire community (Normalized Difference Vegetation Index (NDVI), Normalized Burn Ratio (NBR), differenced NDVI, differenced NBR, relative differenced NBR, Relativized Burn Ratio) and seven Sentinel 2A-specific indices considering the availability of spectral information recorded in the red-edge spectral region. The statistical correlation indicated a slightly stronger relationship between the differenced NBR and the GeoCBI for both Sentinel 2A (r = 0.872) and Landsat-8 OLI (r = 0.845) imagery. Predictive local thresholds of dNBR values showed slightly higher classification accuracy for Sentinel 2A (73.33%) than Landsat-8 OLI (71.11%), suggesting the adequacy of Sentinel 2A for forest fire severity assessment and mapping in Mediterranean pine ecosystems. The evaluation of the classification thresholds calculated in this study over other fires with similar pre-fire conditions could contribute in the operational mapping and reconstruction of the historical patterns of fire severity over the Eastern Mediterranean region.