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Το βιβλίο επικεντρώνεται στην πιο πρόσφατη γεωλογική περίοδο, του Τεταρτογενούς, στις φυσικές διεργασίες που διαμόρφωσαν το ανάγλυφο και την αλληλεπίδρασή τους με την αρχαιολογία. Αναλύει τις κλιματικές μεταβολές κατά το Τεταρτογενές και τις συνέπειες τους στο ανάγλυφο, τις παγετώδεις-μεσοπαγετώδεις περιόδους, τις μεταβολές θαλάσσιας στάθμης, την Ολοκαινική επίκλυση, τις επιπτώσεις στο παράκτιο περιβάλλον, ενώ αναφέρονται οι σύγχρονες τάσεις μεταβολής της θαλάσσιας στάθμης. Αναλύεται η συμβολή της γεωμορφολογίας στην κατανόηση της εξέλιξης του γήινου αναγλύφου της ευρύτερης περιοχής αρχαιολογικών χώρων και ο προσδιορισμός των περιβαλλοντικών-μορφολογικών αλλαγών σε διάφορα γεωμορφολογικά περιβάλλοντα. Περιγράφεται η αλληλεπίδραση του προϊστορικού ανθρώπου με το παλαιοπεριβάλλον, ως προς την εξέλιξη του αναγλύφου ως παράγοντα επιλογής αρχαιολογικών θέσεων, αλλά και ως προς τις ανθρωπογενείς επιπτώσεις στην εξέλιξη του αναγλύφου. Δίνεται παράλληλα έμφαση σε μεθόδους και τεχνικές έρευνας με έμφαση στις νέες τεχνολογίες. Τέλος, αναλύονται χαρακτηριστικές μελέτες περιπτώσεων από τον Ελλαδικό και ευρύτερο Μεσογειακό χώρο σε θέματα αρχαιογεωμορφολογίας. Χρησιμότητα του βιβλίου: Το Τεταρτογενές, παρότι αποτελεί μόνο μια «στιγμή» (2,6 εκ. χρ.) στην ιστορία της Γης, είναι ιδιαίτερα σημαντικό, καθώς κατά τη διάρκειά του εξελίχθηκε ο άνθρωπος ενώ περιλαμβάνει το παρόν. Τα γεγονότα του Τεταρτογενούς αποτυπώθηκαν στα ιζήματα, τα παγοκαλλύματα, τις γεωμορφές και το ανάγλυφο, με μεγαλύτερο βαθμό πληρότητας και χρονικής ανάλυσης, σε σύγκριση με άλλες περιόδους ανάλογης διάρκειας. Η κατανόηση των περιβαλλοντικών μεταβολών, πώς συνέβαλαν στην εξέλιξη του ανθρώπου και στην εξέλιξη αρχαιολογικών θέσεων, έχει ιδιαίτερη σημασία για την επιστημονική κοινότητα και για την κοινωνία. Η μελέτη του Τεταρτογενούς δίνει την δύναμη στους επιστήμονες να κατανοήσουν τις σύγχρονες μεταβολές και να προβλέψουν τις μελλοντικές τάσεις, συμβάλλοντας στην αξιολόγηση των επιπτώσεων στο γεωπεριβάλλον.

This paper examines the remains of ancient quarries located in the western coastal zone of Naxos and presents the evidence they provide for the changing paleogeography of the area for the last 1500 years. On Manto island of Laguna, an aeolianite quarry was located on the coastal zone of the island reaching down to a depth of 2 m. In the area of Plaka, quarrying traces were found on beachrocks at 2 m depth. Based on the geoarchaeological evidence, the sea level 1500 years ago was 2 m lower than today and the shoreline of that time may be traced from the beachrocks protecting both the Laguna and Plaka. Taking into consideration the relative chronology provided by available geological evidence the exploitation of the beachrock quarries at both sites should be linked to the flourishing economy of Naxos during the late antiquity (4th-6th centuries AD) and through the Middle Byzantine period (7th-9th centuries AD).

Beachrocks are a window to the past environmental, geological, sedimentological and morphological conditions that were dominant in the coastal zone during their formation. Furthermore, beachrocks have the ability to reduce coastal erosion impact on sandy beaches. This study focuses on the beachrock formation mechanism through the comparison of cement characteristics, mineral chemistry and sedimentology of beachrock occurrences from two different geological and geographical localities: Diolkos, Corinth, Greece and Sumuide, Okinawa, Japan. In addition, in order to investigate a potential soft engineering method to protect coasts from erosion, artificial beachrock samples were created in vitro using sand samples and ureolytic bacteria from both areas under accelerating conditions. For Okinawa artificial beachrock experiments, the bacteria Pararhodobacter sp. was used, and for Diolkos, it was the bacteria Micrococcus yunnainensis sp. For the natural beachrocks, a multi-analytical approach was accomplished with the use of microscopic investigation, a scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray fluorescence. Correlations were made between natural and artificial beachrocks. Results have shown that Diolkos beachrock was formed in the upper part of the intertidal zone, consisting of detrital material originating from the local bedrock, while Sumuide beachrock formed in the low intertidal-upper subtidal zone, consisting of coral sand and foraminifera fragments. For the artificial beachrocks, three samples were created using the microbial-induced carbonate precipitation (MICP) method, one from Diolkos (Corinth, Greece) and two from Sumuide (Okinawa, Japan). Diolkos artificial beachrock was better consolidated in comparison to Sumuide. Our investigation has shown that bacterial density was the key factor for the creation of the artificial beachrocks, while the samples' granulometry played a secondary role in the process. The laboratory artificial beachrocks show encouraging results for a new soft engineering method to encounter beach erosion while keeping an ecofriendly character by saving energy, material resources and gas emissions. Artificial beachrocks can share the same properties of a natural beachrock and can contribute positively to marine biodiversity as a natural rocky habitat.

The wildfires of summer 2021 in Greece were among the most severe forest fire events that have occurred in the country over the past decade. The conflagration period lasted for 20 days (i.e., from 27 July to 16 August 2021) and resulted in the devastation of an area of more than 3600 Km(2). Forest fire events of similar severity also struck other Mediterranean countries during this period. Apart from their direct impacts, forest fires also render an area more susceptible to runoff erosion by massively removing its vegetation, among other factors. It is clear that immediately after a forest fire, most areas are much more susceptible to erosion. In this paper, we evaluate the erosion hazard of Attica, Northern Euboea, and the Peloponnese that were devastated by forest fires during the summer of 2021 in Greece, in comparison with their geological and geomorphological structures, as well as land cover and management. Given that a very significant part of these areas were burnt during the major conflagrations of this summer, erosion risk, as well as flood risk, are expected to be very high, especially for the coming autumn and winter. For the evaluation of erosion risk, the burnt areas were mapped, and the final erosion-risk maps were constructed through GIS software. The final maps suggest that most of the burnt areas are highly susceptible to future surface runoff erosion events.

The Greek region is known as one of the most seismically and tectonically active areas and it has been struck by some devastating tsunamis, with the most prominent one being the 365 AD event. During the past decade significant research efforts have been made in search of geological and geomorphological evidence of palaeotsunamis along the Greek coasts, primarily through the examination of sediment corings (72% of studies) and secondarily through boulders (i.e., 18%). The published data show that some deposits have been correlated with well-known events such as 365 AD, 1303 AD, the Minoan Santorini Eruption and the 1956 Amorgos earthquake and tsunami, while coastal studies from western Greece have also reported up to five tsunami events, dating as far back as the 6th millennium BC. Although the Ionian Islands, Peloponnese and Crete has been significantly studied, in the Aegean region research efforts are still scarce. Recent events such as the 1956 earthquake and tsunami and the 2020 Samos earthquake and tsunami highlight the need for further studies in this region, to better assess the impact of past events and for improving our knowledge of tsunami history. As Greece is amongst the most seismically active regions globally and has suffered from devastating tsunamis in the past, the identification of tsunami prone areas is essential not only for the scientific community but also for public authorities to design appropriate mitigation measures and prevent tsunami losses in the future.

Coastal lagoons and dunes are of great ecological importance, not only for providing habitats for rare flora and fauna, but also for protecting coastal areas from rising sea levels and storms, etc. Even though these features are unique for sustainable development and are extremely important to the natural environment and economy, they are one of the most vulnerable and threatened ecosystems due to their small size. The western coasts of Naxos (central Aegean Sea) represent an example of such phenomena, with various wetlands bordered by low-lying sand dunes. The aim of our study is to assess the vulnerability and pressures of the western coasts of Naxos Isl. by taking into consideration both natural and anthropogenic factors. We used a variety of approaches for the environmental and geomorphological study of the coastal zone to achieve this goal, including: (a) study of aerial photography from 1960 until today, (b) systematic seasonal aerial monitoring by drone, since 2015, (c) use of DGPS for the mapping of the coastal zone and for obtaining detailed topographic sections, and (d) dune mapping. Our findings reveal the vulnerability of the western coasts of Naxos due to sea level rise, tectonic subsidence, and a variety of anthropogenic pressures, such as uncontrolled parking, vegetation uprooting, sand extractions, and heavy touristic traffic. Therefore, the protection of the sand dunes, their restoration where they have been eroded, the definition of a zone of control, and restriction of human activities must be a key priority.

The Cycladic landscape is characterized by landforms of natural beauty and rarity. Landforms resulting from differential erosion, weathering, tectonics, drainage network, sea level changes, and depositional processes can contribute to the development of geotourism in the area. This can be achieved by supporting conservation, protection and promotion of the geo-environment and nature, educating students, residents, and visitors. The aim of this work is to develop an inventory of the main geomorphosites of Paros and Naxos islands by assessing their scientific and additional values, using qualitative and quantitative criteria. Our results show that, besides the high scientific interest of the 75 geomorphosites, most are also characterized by a high ecological value and can potentially lead to a significant increase in the islands' tourism. The results of this work aim at raise awareness on the geomorphological heritage of central Cyclades and provide a basis for their promotion, protection, and management.

Sea level indicators, such as tidal notches and beachrocks, may pro- vide valuable information for the relative sea level (RSL) changes of an area. The study area, Okinawa, belongs to the Ryukyu Islands, Japan (Pacific Ocean), forming the emerged part of an active island arc, where the Philippine Sea plate is subducting beneath the Asian continent. Evi- dence of emergence has been noted by various studies. Beachrocks have also been studied, however, detailed examinations of their spatial extent and cement characteristics has not been accomplished. The purpose of this study is to discuss the RSL evolution in Okinawa through the re-eval- uation of reported sea level indicators, with additional observations of beachrocks and notches and RSL predictions. Our findings suggest that the majority of Okinawa beachrocks have formed in the intertidal zone. Although the vertical uncertainty of the produced SLIPs is relatively large, there is a good agreement between the different types of sea level indicators. Comparisons with RSL predictions as well as the presence of uplifted notches further suggest that Okinawa island is generally charac- terized by an uplift trend, which is larger in its southern part.