Now showing 1 - 3 of 3
  • Publication
    Geomorphological changes in the coastal area of Farasan Al-Kabir Island (Saudi Arabia) since mid Holocene based on a multi-proxy approach
    (Elsevier Ltd, 2018) ; ;
    Koukousioura, O.
    ;
    Triantaphyllou, M.
    ;
    Vandarakis, D.
    ;
    Marion de Procé, S.
    ;
    Chondraki, V.
    ;
    Kapsimalis, V.
    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 INQUA
    Scopus© Citations 5  191
  • Publication
    Geomorphological evolution and paleoenveronment reconstruction in the northeastern part of lemnos Island (North Aegean Sea)
    (Universite de Liege, 2014) ; ;
    Sidiropoulou, M.
    ;
    Triantaphyllou, M.
    ;
    Vouvalidis, K.
    ;
    Syrides, G.
    ;
    Greco, E.
    The area where the study was made is located in the northeastern coast of Lemnos Island (Greece- North Aegean Sea). This area covers the archaeological settlement of Hephestia which is located in the north part of Purnia Gulf and the coastal area of Alyki Lagoon, which is located in the southeast part of Lemnos coast. The archaeological importance of this area is pointed out not only by its archaeological remains but also by its significant location. The most important site which has been discovered close Hephestia is Poliochni. This is an ancient city considered to have the same date with Troy. The excavations of archaeological site of Hephestia indicate continuous human presence from Late Bronze Age till Byzantine time. The study of the eustatic sea level oscillation in correlation with the neotectonic regimes and die geomorphological observadons, and also the analyses of the deposed sediments, helps us to make a palaeogeographycal reconstruction of the landscape and its impotence to human societies. Therefore, detailed geomorphological mapping, micromorphological, sedimentological and micropaleontological studies of the Holocene coastal deposits have been accomplished. Six boreholes at Alyki lagoon were drilled at selected locations, the deepest one reaches a depth of 11m, and two other boreholes were drilled in Hephestia. The stratigraphy of the late Holocene sediments was studied in detail and samples collected from selected sedimentary layers, were analysed by using micropaleontological techniques. The calculated age from the boreholes gives dates between 5100 B.C. till 820 A.D. Twenty samples of shells and roots were dated using the AMS radiocarbon method in Lyon C14 Laboratory. Geomorphological mapping was carried out using topographic maps at scale of 1:50.000, geological map at a scale of 1:50.000 and observations on the field. Landforms of the coastal alluvial plain, in die shoreline and in die inland were marked and recorded at a scale of 1:50.000. Sea level rise along the interaction of landscape evolution and the impact of human civilization were concluded.
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  • Publication
    Palaeoenvironmental evolution and sea-level changes in the coastal area of NE Lemnos Island (Greece) during the Holocene
    ( 2013) ; ;
    Sidiropoulou, M.
    ;
    Triantaphyllou, M.
    ;
    Vouvalidis, K.
    ;
    Syrides, G.
    ;
    Gonnet, A.
    ;
    Greco, E.
    The study area is located on the northeastern coast of Lemnos Island (North Aegean Sea, 40°2'30N, 25°00'00E). It covers the archaeological settlement of Hephestia located in the Purnia Gulf and the coastal area of Alyki Lagoon. Reconstruction of the palaeogeography used palaeoenvironment data delivered from foraminifera and sea-level changes, providing archeological data about the presence of a potential harbour in the area.Geomorphological mapping as well as sedimentological and micropalaeontological studies of the Holocene coastal deposits were conducted. Four boreholes were drilled from the Alyki Lagoon, reaching 2.5m to 11m at the deepest and two from Hephestia area, reaching a depth of 6m. Twenty-four samples were dated using the AMS radiocarbon method, providing a chronology of the sedimentary units.The calculated age from the boreholes provides dates from 7050calBP to 990calBP There was a constant sea-level rise during the last 7000calBP in the study area. Results from the model of Lambeck sea level curve and sea level index point from Hephestia and Alyki show a vertical difference of 0.5-1.5m below sea level. The foraminiferal fauna analysis shows the development of shallow marine conditions with fresh water influx during 7000-4000calBP and a temporary lagoon environment with fluctuations to shallow bay environment from 4000 to 990calBP. © 2012 Elsevier Ltd and INQUA.
    Scopus© Citations 19  46