Bulletin of the Geological Society of Greece最新文献

{"title":"Study of the coastal sediments of the Loutraki gulf area","authors":"Α. Καραλη-Βουδουρη, Γ. Λειβαδιτησ, A. Μεττοσ","doi":"10.12681/BGSG.17348","DOIUrl":"https://doi.org/10.12681/BGSG.17348","url":null,"abstract":"The study of the sedimentological and mineralogical characteristics of the coastal sediments in the Loutraki gulf, included analyses of a large number of samples, that is granulometry, thin section study and x-ray examination. From these data the granulometry paramètres were assessed such as mean grain size, standard deviation σ, skewness SK, and kurtosis KG of the sediments. The study of the sedimentological parameters based on the mean grain size the offshoreline is covered by coarse grain sand, whereas the tidal zone indicates a high energy environment. The longshoredrift is from Ν to S. Most of the sand is loosely graded in the nearschore area, medium graded in the foreshore area and well graded in the backshore area. Their constant declination indicates a trend for a better gradation of sediments southwards. The latter combined with the mean grain size indicate a reduction of kinetic energy from Ν to S. In addition, the beachrocks, were studied together with their, elevation and their mineral composition .","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84491519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The contribution of the ecozones to the ecostratigraphy. As an example the Plio - Pleistocene basin of Magoula- Karatoulas (Ilia, NE Peloponnesos)","authors":"Α. Σινεκογλου, Α. Μαρκοπούλου-Διακαντώνη, Ο. Dragastan","doi":"10.12681/BGSG.17107","DOIUrl":"https://doi.org/10.12681/BGSG.17107","url":null,"abstract":"In this paper is marked the contribution of the Ecozones to the Ecostratigraphy. As an example we use the drillings (Ml, M2, M3, M4, M6, MIO) coming from the Plio- Pleistocene basin of the Magoula- Karatoulas (Pyrgos, Peloponnesus). Based on the detailed stratigraphical and paleoecological studies of the postalpine sediments (VAGIAS et al. 1995) of the formation of Vounargo (HAGEMAN 1977,1979 & ΚΑΜΠΕΡΗΣ 1987) we attempt to define 15 ecozones, as it is understood the layer or the whole of the layers, which is characterized by an association of fossils (at the level of species, genus or family). The Ecozone reflects the evolution of a sedimentary basin from the bathymetrical point of view as well as the transgressions and the regressions. The Ecozones are often related with the curve of the change of the sea level. The transgression is characterized by the rich fossil associations (species and individuals), while the regression is characterized by a diminution of species and individuals. There are also 11 white spots, which can not be enclosed in Ecozones. They are observed in the drillings M2, M3, M4, M6 and MIO.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89827668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Otoliths from the lower Pliocene of the section Prassies (Rethymnon, ΝW - Crete). Systematics - Paleoecology","authors":"Α. Μαρκοπούλου Διακαντώνη, Γρ. Καγκιουζησ","doi":"10.12681/BGSG.17098","DOIUrl":"https://doi.org/10.12681/BGSG.17098","url":null,"abstract":"","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"83 1","pages":"577"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74520649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stratigraphy and dating of a large slumping event in the Northern Aegean","authors":"V. Lykousis, G. Rousakis, P. Pavlakis, M. Alexandri","doi":"10.12681/BGSG.17132","DOIUrl":"https://doi.org/10.12681/BGSG.17132","url":null,"abstract":"Continuous seismic (Air-Gun) subbotom profiling in the N.Aegean was revealed a large submarine translational slide. The failure zone is extended from about 300m depth down to 800 m and covers an area of 85 Km2. The mean thickness of the slide reaches about 55 m and an estimated total volume of 4 Km3 of Quaternary sediments have been slided along a distance of 6 to 7 Km. Chronostratigraphic analysis of the acoustic reflectors imply that the slide plane is the muddy layer of late Pleistocene age (170-240 Ka BP). AMS dating of sediment cores provided indications that this major slide event occurred 5 to 6 Ka BP.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89310729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surficial mass movements and submarine slope stability analysis between Kerkyra and Paxi slope (Western Greek slope)","authors":"Θ. Χασιώτης, Γ. Παπαθεοδώρου, Γ. Φερεντίνος","doi":"10.12681/bgsg.17127","DOIUrl":"https://doi.org/10.12681/bgsg.17127","url":null,"abstract":"This paper presents the results of a marine geophysical/geotechnical survey, which was carried out between Kerkyra and Paxi slope (part of the western Greek slope). The main bathymorphological features are numerous canyons and intercanyon ridges that exhibit high slope gradients (up to 30Ί). The canyon flanks as well as the ridges are affected by numerous mass movements that include slides, rotated sediment blocks, well-expresed sediment detachment surfaces, mass flows and creeping. Most of the aforementioned movememtns present a retrogressive action of the failure mechanism. The unstable sediment masses are often transported through the canyons and are deposited in the adjacent basin creating a sequence of alternating mass flow deposits and turbiditic/hemipelagic sediments. The gravity cores collected along two ridges, in the Kerkyra and Paxi slopes, revealed a certain sedimentary sequence consisting of calcareous ooze, oxidized mud and a sapropel layer overlaying hemipelagic mud. Along those sediment facies turbiditic muddy to sandy deposits usually appear. The main geotechnical characteristics of these lithofacies are the low undrained shear strength and high water content in the sapropel layer and the inverse relationship of the abovementioned properties in the oxidized mud. The water content of all the sediments is higher than the liquid limit indicating the very soft nature of the deposits and the possible destabilization upon disturbance (i.e. earthquake). The stability of the sedimentary cover was evaluated using the infinite slope, the Bishop and the Janbu methods. The main results that stemmed from the analysis are that (i) the Kerkyra slope is unstable both in static and dynamic conditions and (ii) the Paxi slope is unstable in dynamic conditions, whilst the very surficial layers (<1.5m in thickness) can be also unstable under static conditions. The possible failure planes are located 5-20m under the seabed. The absence of the oxidized mud and sapropel layers in the Kerkyra slope as well as their presence in the Paxi slope, and the presence of an episapropelic layer in the Kerkira-Paxi basin are all indicative of the unstable nature of the seafloor. Cyclic loading by earthquakes, high slope gradients and sediment bedding parallel to the slope are believed to be the predominant slope failure mechanisms in the surveyed area.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76251063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distributed modeling of soil erosion and sediment transport","authors":"V. Hrissanthou, A. Psilovikos","doi":"10.12681/BGSG.17354","DOIUrl":"https://doi.org/10.12681/BGSG.17354","url":null,"abstract":"A mathematical model is used for the estimation of the annual sediment yield resulting from rainfall and runoff at the outlet of Nestos River basin (Toxotes, Thrace, Greece), where the ecologically interesting Nestos delta exists. The model is applied to that part of Nestos River basin (838 km2) which lies downstream of three dams. Two dams (Thissavros and Platanovryssi) have been already constructed, while the third one (Temenos) is under construction. The model consists of three sub-models: a rainfall-runoff sub-model, a surface erosion sub-model and a sediment transport sub-model for streams. This model is also capable of computing the annual erosion amount and sediment yield in the individual sub-basins","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87058239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Consideration of modern sendimentary processes of the Evros river delta front and prodelta, NE Aegean sea","authors":"Θ. Δ. Κανελλοπουλοσ, Β. Καψιμαλησ, Μ. Ο. Αγγελιδησ, Ε. Καμπερη, Α. Καραγεωργησ","doi":"10.12681/BGSG.17305","DOIUrl":"https://doi.org/10.12681/BGSG.17305","url":null,"abstract":"Gravity cores data from the Evros River delta front and prodelta confirm the aspect that the Evros River deltaic deposits tend to west-northwest, along the main direction of the local hydrodynamic regime, preventing the construction of a symmetrical Holocene prism. In the delta front, the terrigenous sediment consists mostly of fine-grained material. Its vertical succession is monotonous with slight differences in grain size or colour, and lack of internal structure or current-produced laminae, indicating almost immutable sedimentary processes as well as long-term discharge fluctuations. The river-borne sand is limited because of its entrapment in the river mouth but sometimes, during extreme conditions (periods of high river discharge, short-lived catastrophic events etc.), can be transported seawards covering an extensive area of the Alexandroupolis Gulf. The negligible biogenic content and the absence of bioturbation effects are attributed to the high rates of deposition. Some bioturbated horizons are produced when sedimentation rates decrease temporarily. The prodelta sediment distribution patterns occur a distinctive zonation along an east-southeast to westnorthwest trend. In the central part, mud dominates, while on both sides of this area, the content of sand gradually increases and becomes the prevalent facies near the coast and in the outer plateau of the gulf. The vertical facies sequences of the upper sedimentary cover are complicated, with many variations in grain size, colour and biogenic content reflecting a complicated manner of deposition. The major feeder of this area is the Evros River providing great amounts of suspended load. Another remarkable source of sand is derived from the coastline, which during storm conditions provides coarse-grained material in the shoreface area. Finally, a sediment supplier of local importance, Loutros River, affects the eastern area of Alexandroupolis building up a small subaqueous fan. In the open sea, the consequences of the modern sedimentation are negligible. The sandy character of the surface and sub-surface sediments, the analysis of biogenic fragments, the long distance from the present-day terrigenous sources are some evidences which lead to the view that the upper sediment body of the southwestern part of the study area has a presumable relict origin. 210Pb profiles are, more of less, consistent showing a sedimentation rate more than 2 cm/yr in the delta front, which decreases to 0.2 cm/yr at about 8 km seaward.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81675410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeoenvironmental significance of a late Miocene benthic foraminifera fauna from Apostoli Formation, Central West Crete, Greece","authors":"H. Drinia","doi":"10.12681/BGSG.17113","DOIUrl":"https://doi.org/10.12681/BGSG.17113","url":null,"abstract":"The palaeoenvironmental and palaeoecological reconstruction of the Apostoli Basin (Crete, Rethymnon Region) during early Late Miocene by means of benthic foraminifers is given. Biologically important factors, such as oxygen and nutrient content of sea-water, played a great role in the evolution of the palaeoecosystem. A gradual deepening took place during the deposition of the Apostoli Formation. The sediments of the lower part of the formation document a shallow-marine environment with vegetation in the neighborhood. In the middle part of the formation sediments are characterized by intermediate oxygenated conditions, whereas the upper part of it is characterized by the establishment of a restricted envrironment, where organic matter accumulates and infaunal opportunistic species capable of surviving in stressed conditions dominate, being favoured by abundant nutrients.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80944395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toe-of-slope facies of the Eocene limestones in Aghioi Pantes sequence (Zakynthos island, Western Greece)","authors":"Μαρία Κατή","doi":"10.12681/BGSG.17304","DOIUrl":"https://doi.org/10.12681/BGSG.17304","url":null,"abstract":"The facies analysis of the Eocene limestones in the Aghioi Pantes section in central Zakynthos, part of the Preapulian carbonate sequence in the greater area, showed three megafacies types: a) graded beds, in which two main subtypes have been recognized, medium- to thin-bedded calcarenites-calcilutites and thick-bedded ruditic calcarenites, consisting mainly of redeposited shallow-water carbonate sands (mostly bioclasts of nummulites and echinoids); based on their sedimentary structures they have been interpreted as low density turbidite and high density turbidite (or sandy debris flows) deposits correspondingly, b) calcareous conglomerates consisting of shallow-water facies lithoclasts and abundant pelagic intraclasts all of which have been interpreted as debris flow deposits and c) folded strata of pelagic-hemipelagic composition that have been interpreted as slumps. Subsequently, the studied limestones constitute exclusively deep-water resedimented facies having been deposited mainly through sediment gravity flows, carrying significant amounts of shallow-water bio- lithoclastic material. The distribution and the organization of this facies association, with the dominance in particular of the base cut-out turbidites, suggest as depositional environment of the studied Eocene limestones a \"low\" in the outer slope connecting the Preapulian platform with the adjacent Ionian basin.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81036226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeocurrent directions as an indicator of Pindos foreland evolution (central and southern part), Western Greece","authors":"J. Vakalas, G. Ananiadis, J. Mpourlokas, D. Poulimenos, K. Getsos, G. Pantopoulos, P. Avramidis, A. Zelilidis, N. Kontopoulos","doi":"10.12681/BGSG.17701","DOIUrl":"https://doi.org/10.12681/BGSG.17701","url":null,"abstract":"In order to estimate the palaeoflow direction of the submarine fans, deposited in the Internal Ionian subbasin of the Pindos Foreland, fifty-one positions along the sub-basin were selected and measurements of palaeocurrents indicators such as flute and groove marks were taken. In the studied area the main palaeoflow direction of turbidites was axial, from south to north in the southern part, and from north to south in the northern part. A minor westward palaeoflow direction is also present. These palaeoflow directions were influenced mainly by the regional tectonic activity, such as internal thrusting (Gavrovo Thrust) and differential activity of the Pindos Thrust which subdivided Pindos foreland into narrow linear sub-basins.","PeriodicalId":9519,"journal":{"name":"Bulletin of the Geological Society of Greece","volume":"101 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74724196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}