Paleoenvironmental evolution of Istron (N.E Crete), during the last 6000 years: Depositional environment, climate and sea level changes

The Istron area is located in northeastern Crete, Gulf of Mirabello, on an alluvial fan of Holocene age. The archaeological importance of this area is suggested not only by its archaeological remains, but also by its significant location. Many important Minoan sites, like Gournia, Kavousi, Pseira, have been discovered near Istro. There are indications of human installations from the Neolithic to the Roman period, proving the continuous human activity in this area. The significant geological location- it represents an area with intense tectonic activity-, geomorphological regime and climatic changes, have influenced regional settlement and the overall cultural development of the area. The study of sea-land interactions during the last seven millennia in relation to the eustatic sea level oscillations and the regional neotectonic regime, as well as the geomorphologic observations and analyses on deposited sediments, aims to reveal the paleogeographic evolution of the landscape and its impact on prehistoric, classical and Roman establishments. A geomorphological mapping of the coastal area along with the drilling of five boreholes and the excavation of six trenches, have therefore been accomplished. Moreover, pollen and microfaunal (benthic foraminifera and ostracodes) analyses have been performed. Six samples were dated using AMS and Conventional radiocarbon techniques providing temporal control of the sediments. Sea level rise along with sea-land interactions to the landscape evolution and the transgression of sea in 5000BP have been verified. Additionally, several implications for the use of land and human impact civilization have been made. © 2007 Lavoisier SAS. All rights reserved

Last glacial geomorphologic records in Mt Chelmos, North Peloponnesus, Greece

This study deals with the analysis of the glacial processes that have affected the relief of Mt Chelmos in northern Peloponnesus, Greece during middle and Late Pleistocene. The goal was to compile a combined geomorphological-geological map of the study area which would enable the chronological stratification of the glacial landforms cropping up on Mt. Chelmos. Chronological stratification was further aided by optically stimulated luminescence (OSL) dating. The map served as the basis upon which the reconstruction and discussion on the phases of the Middle-Late Quaternary paleoclimatic history of Mt. Chelmos have been made. A sophisticated semiautomated method was first used to analyze the Digital Elevation Model (DEM), combined with Aster, Quickbird and ALOS imagery in order to identify glacial and periglacial, as well as karstic features. Then, these features along with other nonrecognizable features from the remote-sensing images were documented in the field. In this way, several glacial landforms were identified, such as moraines and cirques, indicating extended glaciation phases during the middle and Late Pleistocene. Additionally, a ground moraine located at an altitude of 1900-2050 m, within the Spanolakos glacial valley, was dated using the OSL-dating method. The resulting ages indicate a phase of glacier advance/stabilization during MIS-5b (89-86 ka), which is in consistence with pollenrecord evidence from Greece and the Mediterranean. © 2018, Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag GmbH Germany, part of Springer Nature

Geomorphological changes in the coastal area of Farasan Al-Kabir Island (Saudi Arabia) since mid Holocene based on a multi-proxy approach

The geomorphological evolution of the southeastern coastal area of Farasan Al-Kabir Island (Saudi Arabia) is revealed by the mapping of modern landforms and a multi-proxy and high spatial resolution study including grain size, particulate organic carbon, mineralogy, element geochemistry, benthic foraminifera analysis and radiocarbon dating of a 3.3-m long sediment core. The modern geomorphological features comprise a variety of arid landforms, such as plateau, cliffs and pediments of Pleistocene coral limestones, playa depressions located on plateau surfaces, alluvial fans, butte and sandy beaches. The mid Holocene evolution of the borehole area is resulted from the detailed analysis of five sedimentary units detected along the core Matar-1, and includes three distinct stages: (a) from 5253 ± 223 y cal BP to 3138 ± 223 y cal BP, carbonate coarse-grained material consisting of coral fragments, molluscs, calcareous algae and benthic foraminifera are deposited on a shallow marine fringing reefal platform, which becomes progressively a nearshore backreef (around 3675 ± 215 y cal BP), and later (around 3138 ± 223 y cal BP) a reef ramp; (b) since 3040 ± 220 y cal BP the borehole area obtains the characteristics of a high-energy beach that receives increasing inputs of terrigenous material; (c) subsequently, a supratidal backshore setting is established influenced mostly by terrestrial processes and occasionally by marine processes, as it is indicated by the decreasing and sometimes sporadic presence of benthic foraminifera, and recently, a sedimentary veneer consisting of terrigenous, carbonate and evaporite material is formed by terrestrial, mainly wadi and aeolian, processes. © 2018 Elsevier Ltd and INQU

Assessment of the physical impact of a short-term dredging operation on a semi-enclosed environment: South Euboean Gulf, Greece

The potential influence of short-period (May-June 2012) dredging activities (for the installation of a submarine gas pipeline) on physical properties of the marine environment of two shallow-water sites in the Aliveri and Varnavas areas of South Euboean Gulf (Greece) has been evaluated. During the dredging operation in Varnavas, the induced dredge plume traveled up to 750 m from the shoreline, featured by light attenuation coefficient (c(p)) maxima of 4.01-4.61 m(-1) and suspended particulate matter (SPM) concentrations up to 6.01 mg L-1. After dredging the previous parameters reduced to the ambient seawater condition, 0.45 m(-1) and < 2.8 mg L-1 on average, respectively. Likewise in Aliveri, the dredging-associated sediment plume drifted offshore up to 400 m from the shoreline, characterized by c(p) maxima of 2.11-4.86 m(-1) and SPM concentrations up to 13.07 mg L-1. After the completion of the excavation and trenching activities, the c(p) and SPM values were restored to the pre-disturbance condition, 0.6 m(-1) and < 2.2 mg L-1 on average, respectively. The migration of the dredge plume in both dredging sites was accomplished through the formation of intermediate and benthic nepheloid layers, whose development and evolution were governed by seawater stratification and flow regime. The dredging-derived SPM levels appeared to increase within a distance of no more than 300 m from the shoreline (near-field zone). Based on data from the literature, this SPM enhancement together with the deposition of a post-dredging residual mud veneer in the near-field zone could deteriorate local marine biota, but in a reversible way

Assessment of the Coastal Vulnerability to the Ongoing Sea Level Rise for the Exquisite Rhodes Island (SE Aegean Sea, Greece)

The foreseeable acceleration of global sea level rise could potentially pose a major threat to the natural charm and functional integrity of the world-renowned tourist coastal attractions of Rhodes Island, as a result of the anticipated increasing frequency of flooding and erosion events. Hence, this study aims to determine the most vulnerable segments (in terms of physical impact) of the Rhodes coastline through the widely accepted coastal vulnerability index (CVI), applying a combination of well-known, broadly used approaches and methods. The frequency distribution of the current CVI along the island’s coastline suggests a rather worrying high to very high vulnerability of 40%. In addition, a CVI projection to the end of the 21st century (based on the Intergovernmental Panel on Climate Change predictive scenarios) indicates an enhancement of the total vulnerability by 48%, mainly focused on the majority of the western coastline. Hence, a considerable number of popular coastal destinations in the island shall remain under unignorable threat and, therefore, coastal managers and decision-makers need to hatch an integrated plan to minimize economic and natural losses, private property damage and tourism infrastructure deterioration from flooding and erosion episodes, which will most likely be intensified in the future

Paleoenvironmental evolution and sea level change in Saronikos gulf (Aegean sea, Greece): Evidence from the Piraeus coastal plain and elefsis bay sedimentary records

Thorough faunal (benthic foraminifera, ostracods, molluscs) and palynomorph analyses as well as magnetic susceptibility measurements performed on the Piraeus coastal plain sedimentary sequences have shed light on the paleoenvironmental evolution of the area since ca. 9000 cal BP. Benthic and palynomorph assemblages along with magnetic susceptibility suggest a typical lagoonal environment with significant freshwater inputs at the eastern part of the plain after 8700 cal BP. Between 7500 and 5400 cal BP, microfaunal assemblages, mollusc fauna and magnetic susceptibility suggest a shallow marine paleoenvironment, with Piraeus forming a tied island in the center of the bay. Since ca. 4800 cal BP a closed oligohaline lagoon is evidenced in the western part of the Piraeus plain further developed to a marsh after 2800 cal BP, while a coastal environment associated with the fluvio-deltaic system of Kifissos and Korydallos Rivers is continually developing to the west. Signs of cultivation and grazing activities in the area are evidenced since the Early Bronze Age, culminating during the Classical Period. A comparison with a well-dated marine record, recovered from the nearby shallow Elefsis Bay, provides a reasonable estimation of ~5 mm/yr for the absolute sea level rise rate in the inner Saronikos Gulf during the Mid-Holocene. © 2021 by the authors. Licensee MDPI, Basel, Switzerland