The Igoumenitsa area, in northwestern Greece, is composed of organic-rich clay evaporitic formations, of the Ionian zone. They have undergone diagenetic processes, which effect the mineralogical transformations. The purpose of this paper is the study of the mineralogical diagenesis and the possible implications to the geotechnical behavior of these organic-rich clay evaporitic sedimentary rocks. The diagenetic minerals reported in this study are: A: The authigenic swelling clay minerals, smectite and mixed layers of smectite. B. The two characteristic minerals phases of the sulfate diagenesis: I. Bassanite (semi hydrated gypsum-Ca04.l/2H20) and 2. Celestite (SrS04) that can be considered as an indicator of bacterial sulphate reduction, fluid flow and recycling ofevaporites. The two authigenic minerals have derived from the evaporites, mostly by the dehydration of gypsum and by the action of pore water that is charged with the ions derived from the dissolution of preexistent sulfates, halite and carbonates. C. The neoformation of the carbonate minerals aragonite and dolomite, due to probably bacterial sulfate reduction. When organic-clay rich sediments, are associated to evaporites, the diagenetic processes become more complex and interacted. The diagenetic alterations of the gypsum/anhydrite rocks are related to the geotechnical behavior of the formation and may lead to possible karstiflcation. That may cause problems in roads and tunnels construction on or through these evaporitic series

This paper is aimed to study the petrographic characters of the Boeothian Flysch, an Early Cretaceous turbidite deposit which marks the boundary between the External/Internal Hellenides in central-southern Greece, in order to define a preliminary palaeogeographic reconstruction of the Pindos segment of the Alpine Tethys. The Boeothian Flysch is mainly made up by basal conglomerates and arenaceous-pelitic lithofacies, locally interlayered with Calpionellid micrite limestones. This formation is here supposed to belong to the Early Cretaceous flysch family, which marks the contact between the internal and external areas along all the western and central European Alpine Chains for more than 7,000 km, from the Gibraltar Arc to the Balkans via the Calabria-Peloritani Arc. Provenance of these flysch is commonly connected to internal areas, mainly made up by Hercynian crystalline basements and, locally, by ophiolitic complexes. The petrographic data obtained from representative sandstones of the Boeothian Flysch suggest a provenance from internal sources, formed by a Jurassic carbonate platform, metamorphic basements and by ophiolitic complexes, which can be identified with the Pelagonian Terranes (Auct.). An Early Cretaceous uplift and rejuvenation processes, probably related to the late Cretaceous tectogenesis, widely recorded in almost all the central-western Alpine Tethis, affected these internal domains with consequent production of abundant detrital supply in the innermost sector of the Pindos Ocean, whose external margin was bounded by the Parnassos microcontinent.

At Brauron (Vraona or Vravrona) area, E. Attica, near the Brauron bay, by the Erasinos river there is an ancient monument of 415 B.C., dedicated to Artemis. The building material used for the construction of the monument is sandstone originated from Neogene sedimentary deposits. The ancient quarries are located 500m away from the monument and traces of quarring are still visible. Monument ruins had been buried under the mud load curried by Erasinos river for many centuries. During the restoration works of the Temple of Artemis besides the stone found in situ, new material provided by the same formation was as well, used. The restored monument stones display intensive deterioration. The purpose of this paper is to study of the decay forms and investigate the decay causes of the building stone in the monument. The decay forms result from intrinsic (endogenic) and environmental factors. The main endogenic factors of decay of the sandstone used as building material, are: a) the high porosity, and the pore size distribution, b) the calcite cement of the stone c) the mineralogical composition, especially the presence of swelling clay minerals. The main environmental factors of decay that result to the calcite and salt crystallization are a) the burial of the ancient building stones, in the brackish water-mud, for centuries b) the frequent floods and possible pollution of the nearby Erasinos river c) the acid rain and aerosol attack d) the bioteterioration. The conclusions of this case study may have application on other monuments of historical interest, in similar environment