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The Saronikos Gulf hosts the northwestern end of the South Aegean Active Volcanic Arc. It is affected by extensional back-arc tectonism in a prominent N-S direction, while older E-W rifting is also manifested. Recently acquired swath bathymetry and high-resolution seismic profiles led to the precise morphological mapping of five Quaternary continental shelf basins, along with their neotectonic delineations and their cross-correlation to the onshore active fault zones. Aegina and Methana basins, in the southeast Saronikos Gulf, display subsidence along ENE-WSW and NW-SE axes, and continuous marine sedimentation throughout the Upper Quaternary. Salamina basin in the northeast Saronikos Gulf is a shallow, relatively stable sedimentary basin, intermittently connected to the SE and NW Saronikos Gulf through the Aegina-Fleves and the Aegina-Salamina plateau respectively. In the western and most active region of Saronikos Gulf, the onshore E-W–trending faults of Kechrees and Agios Vassileios extend eastwards until the Salamina-Aegina plateau. The Megara basin is WNW-ESE oriented, possibly affected by the N-S Korfos fault valley, which connects the Megara and Epidavros basins. E-W–trending faults tilt the Quaternary sedimentary blocks, in compatibility to the N-S extensional tectonic regime of the adjacent Gulf of Corinth. Prograding clinoforms in the Megara and Epidavros basins reveal an Upper Quaternary-age intermittent connection to the open sea. Mass transport deposits and volcanic flows in-between the Upper Quaternary sediments of the Epidavros basin manifest the 500–400 ka tectonic phase that affected both the NE Peloponnese coast and the active N-S and NW-SE to WNW-ESE striking faults of the Epidavros basin margin.

Sediment transport processes from the slopes to the deep basins were studied in the southern Cretan margin (Eastern Mediterranean) by means of swath bathymetry, seismic reflection (airgun) profiling, and gravity coring. Mud/silt turbidites, developed in structureless or laminated patterns, appear to dominate the continental slope and the 2700–3600-m deep depressions of Samaria, Messara, and Gortys. These deposits are the result of successive mass transport events and turbidity currents. Over-steepening caused by strike–slip shearing associated with extensional tectonic activity in the shallow crustal levels, shaking due to significant seismic activity, and the presence of weak sediment layers are responsible for frequent triggering of slope failures and the subsequent formation of turbidity currents on the Gavdos slope. On the Cretan slope, sediments channeled as turbidity currents through canyons proved to be the major delivery mechanism, together with debris flows. Subordinate contributions of hemipelagic sediments occur only in the Messara basin. Moreover, steep non-incised slope areas and slope-confined canyons of the Gavdos slope were found to provide comparable sediment contribution with the fluvially connected canyons of the Cretan slope.

Nisyros volcanic island, at the eastern end of the Aegean Volcanic Arc, was mainly constructed after the ultra-Plinian Kos Plateau Tuff (KPT) eruption at 161 ka. The surrounding submarine area consists mostly of marginal mass-transport deposits that commonly characterize insular stratovolcanoes. This study aims at providing insights into the deposition and volume of such deposits by elucidating the products of a mega-eruption and subsequent paroxysmal volcanicity, typical of subduction zone-island arc systems. Seismic reflection and multibeam bathymetry around Nisyros identify pyroclastic and debris flow deposits covering areas several orders of magnitude greater than the island. The entire seabed between the basins of East Kos and Tilos is underlain by a ~7 km3 volcaniclastic unit that defines a ubiquitous basal unconformity at an average depth of 30 m below the seafloor. Southwest of Nisyros, two groups of avalanche deposits from the same unit are bathymetrically identified on the slopes of the northernmost Karpathos basin apron. Seismic stratigraphic markers that trace the unit on the shelf of Tilos suggest it is concomitant with the KPT eruption. This formerly unknown submarine expansion of the KPT deposits into three neighboring basins, when added to the volume of this massive unit to the rest of the Nisyros surroundings, gives it an explosivity index (VEI) >6. As such, it represents the largest Quaternary subaqueous volcanogenic mass flow deposit of the eastern Mediterranean. From this dataset, it can be inferred that the submarine advance of the erupted material occurred mainly through erosive gravity flows, envisioned as the main dispersion mechanism of large-scale subaqueous pyroclastic deposits of Plinian eruptions. East of Nisyros, unique small-scale diapiric domes and seafloor mounds are attributed to loading by the KPT in combination with regional faulting. Subsequent Nisyros effusive activity produced pyroclastic units around the northeast as well as debris avalanche and lava flows south of the island. These have been correlated to known onshore formations. The present study documents the intensity and impacts of a volcanic island mega-eruption and paroxysmal epilogue over a cycle of 100 kyr.

The early Miocene Sigri Pyroclastic Formation in western Lesbos Island hosts the famous petrified forest of silicified tree fossils, protected as a UNESCO Geopark. The formation consists primarily of flow tuffs, mud flow deposits and stream conglomerate. Hydrothermal veins rich in silica, iron, and manganese are preferentially developed in major fault zones and along paleosols. The purpose of this study is to understand the nature of the hydrothermal system and its relationship to the preservation of tree fossils. Samples were collected from fresh and altered pyroclastic rocks, hydrothermal veins and petrified wood. Rock mineralogy and chemistry were investigated using a petrographic microscope, scanning electron microscope, electron microprobe, Laser Raman spectroscopy, and X-ray powder diffraction. Early devitrification of volcanic glass in tuffs formed opaline silica and locally resulted in smectite. At the same time, fossil trees were partly replaced by amorphous silica. Epithermal alteration and hydrothermal veins include (1) adularia + silica + kaolinite; (2) jarosite + hematite + amorphous silica; and (3) “Fe-oxide” and/or “Mn-oxide” + amorphous silica. The MnSi mixture and Mn-oxides comprise structurally amorphous romanechite with some more crystalline grains of todorokite, ramsdellite and/or nsutite. The mixtures of Fe-oxides and silica are also largely amorphous and include α-cristobalite. Such mixtures replace parts of the petrified wood including cell walls. The various colors observed from the petrified wood are principally related to the abundance of iron and organic matter. Faulting and complex hydrothermal alteration was related to the emplacement of laccoliths and dykes around 18 Ma, 1–3 Ma after deposition of the Sigri Pyroclastic Formation. The observed types of low temperature epithermal alteration are compared with that produced by different circulating waters in the modern Taupo volcanic zone of New Zealand. Hydrothermal deposition of Fe-oxides and silica played an important role in the preservation of the petrified forest.

The Kos-Nisyros-Yali volcanic region is one of the centers in the South Aegean Volcanic Arc to exhibit Holocene volcanic activity, with poorly dated thin tephra layers on Yali associated with Neolithic artifacts. This paper helps to resolve the age and character of early to mid - Holocene volcanism in the South Aegean Sea. It presents the lithostratigraphic record of seven newly recovered cores from this region at the SE termination of the South Aegean Volcanic Arc. The cores were scanned for magnetic susceptibility, split, logged and sampled at one centimeter resolution for carbonate content. Selected intervals were analyzed for grain size, organic carbon content, and feldspar content by XRD, in order to identify lithostratigraphic levels with enhanced volcanic minerals. Subsequently, textural and electron microprobe analyses of volcanic glass shards and pumice fragments were carried out on 20 samples. Chronology was inferred from the upper and lower limits of the S1 sapropel and from five AMS 14C dates on foraminifera. In several cores in the S1 interval, mixed volcanic glass types that compositionally correlate with the Nisyros Lower and Upper Pumice, Yali pumices and KPT suggest that the volcanic glass is reworked from previous deposits and transported by turbidity currents. Cores from deep water northeast and northwest of Yali have a single population of tephra at two or more horizons within S1 that geochemically resembles Holocene Yali–4 pumice on land. These beds likely represent air-fall ash that was dispersed at least 10 km from Yali, with ages of 8 and 10 ka. Moreover we report two or more tephra layers within S1 from the Kalymnos Basin that are not reworked and geochemically resemble Santorini tephra. This study thus confirms the occurrence of small early Holocene eruptions at Yali and provides possible evidence for early Holocene eruptions at Santorini.

Methana peninsula shows the longest recorded volcanic history at the western end of the South Aegean Active Volcanic Arc, including volcanic products from the Upper Pliocene to recent times. The volcanic rocks comprise widespread dacite domes and andesite lava flows from several small volcanic centers and are only imprecisely dated. In this paper, the integrated analysis of swath bathymetry, side scan sonar data, and high resolution seismic reflection profiles correlated with core samples, has allowed detailed mapping, characterization and precise chronological identification of the Pausanias submarine volcanic field activity offshore northern Methana. Six volcanic cones or domes are recognized, typically 1–3 km in diameter, some elongated NE–SW and some with a small central crater. On their flanks, the acoustically reflective volcanic rocks pass laterally into incoherent transparent seismic facies interpreted as volcaniclastic deposits, possibly including hyaloclastites, that interfinger with the regional basin sediments. A sea-bottom hummocky field, is interpreted as volcanic avalanche and appears to be the submarine continuation of the volcaniclastic apron of northern Methana peninsula. A robust chronostratigraphic framework has been established, based on the recognition of shoreline progradational units and their connection with Quaternary eustatic sea level cycles. Relative dating of the different phases of submarine volcanic activity during the Upper Quaternary has been achieved by correlating the imaged volcaniclastic flows, interlayered within the chronostratigraphically dated sediments. Dating by stratigraphic position, relative to 2D imaged eustatic sea level clinoform wedges appears to be more precise than radiometric methods on land. Three main submarine Volcanic Events (VE) are recognized: VE3 at ~450 ka, a less precisely dated interval at 200–130 ka (VE2), and VE1 at ~14 ka. Based on chronostratigraphic constraints, subsidence rates of 0.16 (±0.008) m/ka in-between Marine Isotopic Stages 6 and 12 and 0.19 (±0.009) m/ka in-between Marine Isotopic Stages 12 and 16 were estimated for the marine basin north of Methana. The morphological similarity to the onshore volcanoes of Methana Peninsula implies that magmatic constructive processes were dominant, regardless of whether in air or in water. The Upper Quaternary submarine volcanic rocks of Methana differ from those known from stratovolcanoes elsewhere in the Mediterranean, (e.g. Kos-Nisyros, Stromboli) and in other volcanic arcs (e.g., Montserrat, St Vincent), in the submarine development of domes or small cones, the paucity of volcano flank failure deposits and the lack of explosive events. Pausanias volcanic products date the onset of NE–SW faulting as well as the following tectonic phase of E-W striking faults, possibly related to basin inversion, caused by a major rifting phase that also affected most of the South Aegean Arc and the adjacent Gulfs of Corinth and Argolikos.

Marine environmental status can be assessed through the study of bio-indicator species. Here, we monitor natural environmental stress by the occurrence of morphologically abnormal planktonic foraminiferal specimens from a suite of surface sediments in the eastern Mediterranean Sea. We also compare Scanning Electron Microscopy (SEM) abnormality observations from sapropel S1-derived sediments in the Aegean, Libyan and Levantine basins, since they provide a direct record of a natural stress experiment that took place over past time scales. At initial sapropel deposition levels, we observe increased growth asymmetry in Globigerinoides ruber twinned and twisted individuals, possibly associated with eutrophication and anoxia. In modern material, a range of malformations and aberrant morphologies from slight deformity with smaller or overdeveloped chambers to more severe deformity with abnormally protruding or misplaced chambers, distorted spirals, and double tests is also observed, as a result of the hypersaline, oligotrophic and oxygen-depleted nature of the Mediterranean Sea water column. Overall, we highlight the current use of the relative abundance of abnormal tests as a bio-indicator for monitoring natural stress, especially the occurrence of twin specimens as indicative of high-salinity stress conditions, and further illustrate the necessity to map both their spatial and temporal distribution for accurate paleoenvironmental reconstructions. Such an approach presents the advantage to rapidly provide information over wide spatial and temporal scales, extending our ability to monitor a wide variety of environments (from coastal to the open-sea). However, further investigations should extend this approach to test the robustness of our findings in a number of similar oceanic settings.

Planktonic foraminiferal geochemistry presents a valuable archive for paleoceanographic reconstructions. However in high salinity and carbonate super-saturated settings, precipitation of inorganic calcite onto foraminiferal tests can potentially alter the primary geochemical signal, biasing Mg/Ca ratios and ensuing paleoceanographic reconstructions. Here we utilize test biometrics (specifically related to the compression and elongation of the last chambers) to identify four distinct morphotypes (labelled A-D) of the paleoceanographically important planktonic foraminifer species Globigerinoides ruber, and further evaluate their susceptibility to diagenetic alteration from a suite of surface sediments in the eastern Mediterranean Sea. The three distinguished morphotypes (A–C) correspond to previously recognized morphotypes (“Normal”, “Platys”, “Elongate” respectively) in the Mediterranean Sea, while the remaining (D or “Twin”) was designated for the first time. We also compare Scanning Electron Microscopy (SEM) observations performed on four distinguished morphotypes, indicative of potential diagenetic alteration influence. We identified 3 different overgrowth stages (OGA1–OGA3), as a function of geography in the study area. The early diagenesis degrees (involving all the morphotypes) are only geographically distinct along the eastern Mediterranean (increasing to the south), since the morphology does not play a role in the likelihood of diagenetic alteration. Particularly, in the north Aegean Sea, SEM analyses reveal the absence or limited presence of an overgrowth imprint in all recognized morphotypes, while in the central-south Aegean and Levantine Seas they show higher amplitudes of diagenetic overprint supporting the general trend to advanced diagenetic alteration. The semi-enclosed oligotrophic nature and high salinity of this setting, in combination with the different degree of carbonate precipitation and calcite super-saturation between the sub-basins, could be the most plausible explanation for the observed diagenetic stages. The ecological divergence between the morphotypes, determined by different controlling factors (depth habitats, growth optimum/stressed conditions, productivity, stratification, near-/offshore-conditions), in combination with their different test morphologies (related to shell porosity), control directly their distribution pattern. Regardless of the exact mechanism of early diagenetic processes, our results remove one potential source of uncertainty in Mg/Ca-T reconstructions in such highly evaporitive basins of the (sub)tropics, and potentially open the door to the calculation of a multivariate calibration with greater accuracy. However, further investigations should extend this approach to test the robustness of our findings in a number of similar oceanic settings.

International audience; New sedimentological, micropaleontological and geochemical data from the Upper Miocene pre-evaporitic sedimentary sequence of the Faneromeni section (Crete Island, eastern Mediterranean) revealed a stepwise restriction of the Mediterranean Sea preceding the Messinian Salinity Crisis (MSC), which was modulated by a sedimentary cyclicity responding to orbital parameters. This cyclicity is manifested by lithological alternations from laminated to indurated homogeneous marls and clayey limestones, and covers the Tortonian-Messinian Transition (TMT; 7.6–6.7 Ma). This time window covers the successive closure of the marine Mediterranean-Atlantic gateways, which culminated in the onset of the MSC. In the present study, we present the first evidence for changes in the upper water column reflected by sea surface temperature (SST) and salinity (SSS) variations that correlate with pronounced paleoclimatic fluctuations. Planktonic foraminiferal isotopes, in combination with paired mixed layer Sr/Ca-derived SST data, reveal that the very warm late Tortonian interval has been followed by a strong long-term cooling (~10 °C) and desalination (~10‰) trend during the earliest Messinian, attributed to the paroxysmal phase of the so-called “siphon” event. In particular, the climate shift that occurred at the end of a global carbon isotope (δ13C) decrease suggests that changes in the carbon cycle were instrumental in driving late Miocene climate dynamics (cooling and aridity) in the progressively isolated eastern Mediterranean Sea. The observed salinity variability during this time interval also provides further insights about seasonal freshwater inputs and gives new support to the much-debated hydrologic regime (linear salinity increase vs step-function evolution with strong salinity fluctuations) preceding the deposition of evaporites. The novel methodology of foraminiferal Sr/Ca paleothermometry and results of this study could have numerous potential applications to other regions and relevant extreme geological events. Therefore, in the near future we expect this approach to add important new information to our understanding of Neogene climates.

The islet of Pyrgousa, 8 km west of Nisyros, has andesites overlain by proximal deposits of the Kos Plateau Tuff (KPT). These andesites record the evolution of the Kos-Nisyros volcanic centre prior to the large KPT eruption at 161 ka. This precursory activity had previously been recorded only in dacites and rhyolites in the Kefalos Peninsula, farther from the volcanic centre. This study investigated the age, geochemistry, mineralogy, and petrogenesis of the andesite domes, probable flows, and associated talus breccias on Pyrgousa. Analysed samples are basaltic andesite and andesite, with strong enrichment in Ba and Sr and low values of Ti and Zr. An 40Ar/39Ar date of 1.9 ± 0.1 Ma on biotite is similar to dates from dacite and rhyolite stocks and domes in the Kefalos Peninsula, and like those dates is the maximum age due to excess 40Ar. There is no evidence on Pyrgousa for a stratovolcano precursor of the KPT eruption. The andesite domes geochemically resemble Pliocene domes in Methana and Aegina that mark the onset of magmatism in the northwestern South Aegean Arc, with an important magma component derived from subcontinental lithospheric mantle. These early andesites heated the upper crust, thus facilitating the growth of upper crustal magma chambers, which were filled by felsic crystal mush derived by differentiation of hydrous intermediate magmas with a more asthenospheric signature.

This study investigates the interplay of evolving tectonic and submarine sedimentation processes in the northwest Aegean Sea using marine multichannel seismic profiles. We identify an extensive basin developing in the Thermaikos Gulf inner shelf, outer shelf, and slope leading to the 1500 m deep West North Aegean Trough (NAT). We establish the unconformable extent of Eocene and Oligocene sequences on the upper shelf and trace their continuation in the deeper shelf and slope of Thermaikos Gulf. The start of the Miocene and Middle Miocene developed below the well-established Messinian bounding reflectors that are mostly erosional. Important lateral variations are observed within the Messinian sequence, which is up to 0.8 s thick. Messinian prograding clinoforms are identified on the Thermaikos Gulf shelf and southeast of Chalkidiki, and a zone of irregular reflectors is attributed to the Messinian salt layer. The transpressional deformation of the Messinian in the southwestern margin constrains the timing of westward progradation of the North Anatolian Fault during Messinian. The Pliocene-Quaternary sediments are 0.6–1.8 s thick, showing the overwhelming effect of tectonics on sedimentation plus the northwards Quaternary activation at the Thermaikos apron.

One of the most enigmatic features of long-term Cenozoic climatic evolution, with some analog potential for present/future global climate change, is the last sustained warm and high-atmospheric CO 2 interval in Earth's history, which started after the end of the Messinian Salinity Crisis (5.971–5.332 Ma) in the Mediterranean Sea. We present high-resolution, astronomically-tuned climate (Mg/Ca, δ 18 O) and productivity (Ba/Ca, δ 13 C) proxy records from the planktonic foraminifera Globigerinoides obliquus in the Kalamaki section (Zakynthos Island, Greece), which sheds new light on the early Pliocene Mediterranean hydrographic dynamics, and the associated climatic transition from 5.33 to 5.11 Ma. We recognized four distinct climatic phases with variable amplitude changes: (1) very warm climate interval prior to 5.28 Ma characterized by minimum ice volume, large salinity fluctuations, enhanced productivity, and intense river runoff, (2) stable paleoceanographic conditions from 5.28 to 5.23 Ma, which reflect a relatively warm and mesotrophic to eutrophic open-marine environment with improved ventilation, (3) a brief interval (20 ky) characterized by the most pronounced ice growth and intense cooling (∼ 5 °C) coupled with the abrupt decrease of ventilation and primary productivity, and (4) reinstatement of relatively stable conditions (warm and well-ventilated mesotrophic upper water column) in conjunction with relatively stable sea-level after 5.21 Ma. Overall, the succession of these phases provides an explanation for the more variable Mediterranean climate and stronger hydrographic variability with respect to other regions during the early Pliocene.

The South Evoikos Basin is a marginal basin in the Aegean Sea which receives little terrigenous supply and its sedimentation is dominated by hemipelagic processes. Late Quaternary benthic and planktonic foraminifera from core PAG-155 are investigated in order to understand their response to the glacial-interglacial cycles in this region. The quantitative analysis of planktonic foraminifera, coupled with accelerator mass spectrometry (14C-AMS) radiocarbon date measurements, provide an integrated chrono-stratigraphic time framework over the last 90 ka (time interval between late Marine Isotopic Stages 5 and 1; MIS5-MIS1). The temporary appearance and disappearance as well as several abundance peaks in the quantitative distribution of selected climate-sensitive planktonic species allowed the identification of several eco-bioevents, useful to accurately mark the boundaries of the eco-biozones widely recognized in the Mediterranean records and used for large-scale correlations. The established bio-ecozonation scheme allows a detailed palaecological reconstruction for the late Pleistocene archive in the central Aegean, and furthermore provides a notable contribution for palaeoclimatic studies, facilitating intercorrelations between various oceanographic basins. The quantitative analyses of benthic foraminifera identify four distinct assemblages, namely Biofacies: Elphidium spp., Haynesina spp. Biofacies, characterized by neritic species, dominated during the transition from MIS 5 to MIS 4; Cassidulina laevigata/carinata Biofacies dominated till 42 ka (transgressive trend from MIS 4 to MIS 3); Bulimina gibba Biofacies dominated from 42 ka to 9.5 ka (extensive regression MIS 3,2 through lowstand and early transgression; beginning of MIS 1); Bulimina marginata, Uvigerina spp. Biofacies dominated from 9.5 ka to the present (late transgression through early highstand; MIS 1)., This study showed that the South Evoikos Basin which is characterized by its critical depths and connections to the open sea, and its small volume water masses that nourished foraminiferal assemblages, accurately records 5th−4th order sea level and climatic fluctuations. Especially, the basin's limited communication with the open ocean implies that any climatic signals will be recorded in an amplified fashion, and therefore this heightened sensitivity to the effects of climate variability further underlies the prominent role of such marginal basins in the understanding of the global climatic evolution.

The stacking pattern of shoreline progradational sequences in subsiding basins have been used as a chronologic tool in the Mediterranean region. Most previous studies have used a few key seismic lines seaward of deltas, where the record is complicated by deltaic distributary switching. Southeastern Saronikos Gulf, in the western Aegean Sea at the northwestern end of the South Aegean Arc, lacks large river input of sediment. The ENE-WSW and NW-SE trending neotectonic Aegina and Methana basins lie between the tectonically active Gulf of Corinth and the relatively stable Cyclades plateau. New high-resolution seismic profiles from southeastern Saronikos Gulf have been interpreted according to the principles of seismic and sequence stratigraphy. Alpine basement and marine Pliocene sediments have been recognized in the surrounding basin margins and more than 300 m and 150 m of unconsolidated sediments have been mapped in Aegina and Methana basin respectively. Progradational clinoforms that toplap against transgressive surfaces, have been traced along strike, leading to the establishment of a robust chronostratigraphic framework further controlled by sedimentation rates as extracted from cores. Southeastern Saronikos Gulf poses an outstanding example of development of progradational wedges formed within a microtidal, wave dominated regime of low sedimentation rates, between 2.8 cm/ka and 3.2 cm/ka, within the framework of low subsiding basins with rates between 0.03 and 0.31 m/ka. In this environment, more than 180 well preserved shoreline progradational units, with attributes similar to the ones reported from the Aegean and Eastern Mediterranean seas, have been mapped and correlated to sea level lowstands back to 866 ka. Deeper Mid-Pleistocene progradational units are also recognized, tentatively back to 1.4 Ma. Subsidence rate shows a dramatic decrease in the last 1 Ma and significant numbers of faults became inactive during the last 130 ka. In Early-Middle Quaternary, Methana basin was an isolated lake and extended terrestrial areas were shaped in the Poros-Agios Georgios plateau during sea level lowstands. Aegina basin was continuously connected to the Aegean through the Agios Georgios fault valley. This study demonstrates the robustness of chronology based on stacked shoreline progradational sequences and its applicability to determining rates of tectonic subsidence.

A high-resolution palaeoenvironmental investigation was conducted on the benthic foraminiferal record of two continuous sediment cores (DEH 5, DEH 1) in order to reconstruct the latest-Pleistocene to Holocene history of the South Evoikos Gulf (central Aegean Sea). This shallow (max. depth ~75 m), semi-enclosed continental shelf setting has been heavily affected by the latest-glacial to modern-interglacial relative sea-level and climate oscillations that strongly affected the benthic foraminiferal community. The identified meiofaunal biofacies associated with the chronological framework allowed the recognition of four main time phases in the palaeoenvironmental and palaeobathymetric evolution of the gulf: (i) During the latest glacial-interglacial transition (>15.17 ka BP), highly-stressed confined shallow lagoonal conditions correspond to the Last Glacial Maximum (LGM) sea-level lowstand. During that time, a natural barrier located at the mouth of the gulf effectively prevented communication with the open Aegean Sea and amplified the contribution of the local aquifers. (ii) The early post-LGM sea-level rise was initially marked by a weak marine connection, dominated by a pronounced seaward river progradation of local aquifers. However, immediately after (~14.7 ka BP), an enhanced rate of sea-level rise, synchronous with the Meltwater Pulse 1A (MWP-1A), is observed. At the end of the Pleistocene, the sedimentation rates decreased dramatically, as a result of the Younger Dryas (YD) cooling event. (iii) The Holocene sea-level rise was characterized by an extremely abrupt marine transgression (~11.29 ka BP), during which the sea-level in the Aegean Sea reached 55 m below present sea level (b.p.s.l) and forcedly overcame the barrier that previously separated the gulf from the open sea. At ~8.67–7.77 ka BP, an upper circalittoral eutrophic environment emerged, which coincided with the coeval deposition of the sapropel S1 in the Eastern Mediterranean Sea. Immediately after, re-ventilation conditions were reinstated. (iv) The Holocene sea-level high-stand is characterized by upper circalittoral high-energy and vegetated conditions on the sea floor. Regional index terms Eastern Mediterranean; Central Aegean Sea; Greece; South Evoikos Gulf.

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High-resolution swath-bathymetry has been acquired during recent surveys in Saronikos Gulf, near the densely populated city of Athens. This paper presents the first detailed bathymetric map, at a scale of 1:12,000, of the active Submarine Pausanias Volcanic Field located offshore NW Methana Peninsula in Saronikos Gulf, Aegean Sea (Main Map). Rugged morphology characterizes the volcanic field that includes mainly cone-shaped features. Six volcanic outcrops, covering an area of about 12 km2, have been morpho-bathymetrically outlined, and their sub-bottom character has been described by the integration of 2D seismic reflection profiles. Two groups of outcrops have been distinguished. An older group comprising more complex, erosional-shaped outcrops, and a younger group consisting of sub-conical outcrops. Both groups have been morphologically correlated to their onshore equivalents in the adjacent peninsula of Methana. Despite the active tectonic regime of the region, no evidence of mass transport-related features have been observed.

The purpose of this study is to collect micropalaeontological evidence concerning the palaeoenvironmental changes that took place at Southern Evoikos Gulf during the Holocene. Southern Evoikos Gulf is a shallow epicontinental basin, at the northern prolongation of the Cycladic Platform (Western Aegean Sea, Greece). The study area of the present research is located at the northern part of this gulf. Two cores, DEH 1 and DEH 5, the sedimentary record of which covers the last 13910 cal. yr B.P., were recovered from 70m and 75.5m water depth respectively and a detailed quantitative and qualitative ostracod analysis is performed in 88 samples of DEH 5 and 56 samples of DEH1. Atotal of 45 ostracod species were identified from DEH1 and 52 species from DEH5. The distribution of ostracod assemblages in the investigated cores indicates that a restricted shallow oligohaline lagoon was formed sometime before 13540 cal yr BP at the northern basin of the Southern Evoikos Gulf. This closed lagoon existed in the area until 11065 cal yr BP. Subsequently, during the Holocene, an unrestricted communication with the sea was established and a marine coastal environment was formed, with a gradual transition (the beginning of which is estimated at about 8000 cal yr BP in DEH 1) from an infralittoral to a circalittoral one.

North Evoikos Gulf constitutes a deep (450 m) semi-enclosed basin in east-central Greece connected to the Aegean Sea via a 42-m sill to the north and a 40-m wide, 8-m deep channel to the south. Six gravity cores retrieved from different physiographic settings of the Gulf were analyzed for their benthic foraminiferal content, in order to reconstruct the local and regional palaeoenvironmental changes. Species Correspondence Analysis separates the foraminifera into 4 clusters: Cluster 1 is composed of Agglutinated species, Elphidium spp. and Ammonia beccarii ; Cluster 2 is exclusively composed of Bulimina marginata ; Cluster 3 consists of Bolivina spathulata and Bulimina costata and finally Cluster 4 comprises the 10 remaining species: Cibicides lobatulus , Cibicidoides pachyderma , Bulimina aculeata , Cancris oblonga , Melonis barleeanum , Chilostomella oolina , Cassidulina laevigata , Hyalinea balthica and Miliolidae. These clusters represent four distinct foraminiferal biofacies and are interpreted as reflecting different ecological conditions: Biofacies p-H corresponds to the proximal part of the shelf and it is characterised by the absence of foraminifera, skeletal debris and abundant peloids. Its topmost part shows an erosional surface, aged 32.4 ka, characterised by shell debris, and the appearance of few shallow marine benthic foraminifera. Biofacies Ia and Ib consist of a low-diversity Holocene assemblage which is mainly dominated by Textularia spp. and Elphidium spp., reflecting a low-energy restricted lagoon and the deeper water assemblage of B. marginata and H. balthica (Biofacies Ib) as well as by a mollusc assemblage dominated by Corbula gibba . These biofacies are only present in the mid-shelf setting. Biofacies II (Cluster 3: B. spathulata – B. costata ) shows a possible positive correlation with nutrient contents and it exhibits a complementary pattern of distribution with Biofacies III (Cluster 4: B. marginata ). Two main palaeoenvironmental settings were recognized: a) In the first setting dominated by Biofacies Ia and Ib, the succession of the benthic faunas is mainly controlled by the ongoing sea level rise; b) in the second setting, the species typical of shelf environment ( C. laevigata – H. balthica ) give way to opportunistic species ( B. spathulata ) and species that are more resistant to bottom water changes ( B. marginata ). This pattern is attributed to variations in the food chain and oxygenation. North Evoikos Gulf during the Uppermost Quaternary reflects a passive response to a globally fluctuating sea level that was not significantly modified by dramatic tectonic processes. Therefore, its palaeoceanographic evolution is primarily driven by climatic (eustatic) processes and accurately depicts local conditions.

On subsiding continental shelves, the style of stacked coastal and deltaic progradational packages is directly dependent on relative sea-level changes. In the past ∼0.6 Ma, sea-level change has been dominated by asymmetric 100 ka eustatic sea-level cycles, whereas the record of sea-level changes in earlier Pleistocene progradational sequences is less clear. In a steadily subsiding basin in which accommodation balances sediment flux, the depth of a eustatic lowstand determines the paleo-depth of the deepest clinoform inflection point and the seaward limit of the erosional transgressive surface, whereas the duration of a lowstand controls the amount of progradation that takes place. We report high-resolution seismic profiles of an exceptionally preserved coastal progradational sequence from a coastal embayment in the Aegean Sea that is subsiding at ∼100 m/Ma. The seismic profiles show clinoforms of smaller amplitude and volume that were deposited before the 100 ka cyclic progradational units. This contrasts with literature reports of complexity in progradational sequences at that time. We assume that published stacked benthic foram O-isotope records are a good proxy for the duration and a reasonable proxy for the amplitude of Pleistocene eustatic sea-level cycles. The MIS 6–5 eustatic sea-level rise is recognised based on sedimentation rates from cores. The underlying major progradational units are correlated with the long-duration, extreme lowstand 100 ka cycles of MIS 6, 12 and 16. Changes in the elevation of lowstand inflection points in clinoforms are used to tentatively extend the record back to MIS 38, by comparison with the benthic foram proxy. The deposits of the higher and longer highstands of MIS 25, 31 and 37 are also recognised. This record provides a testable template for future studies of short early Pleistocene sections on land and raises questions of detail about parts of the published δ 18 O records. It independently supports the recent evidence that the Mid-Pleistocene transition was an abrupt event, with an extreme lowstand in MIS 22.

North Evoikos Gulf, Greece, constitutes a landlocked, epicontinental and semi-enclosed basin, connected to the central-west Aegean Sea through a strait, probably not allowing full exchange of intermediate and deep water masses. Benthic foraminifer analyses were carried out on a Late Quaternary core from the outer shelf of the basin with the aim of tracing palaeoceanographic changes. The benthic foraminifer species percentage per sample was used to calculate two main biological proxies: the Benthic Foraminifer Oxygen Index (BFOI) and Benthic Foraminifer High Productivity (BFHP) proxy estimated by grouping benthic foraminifer taxa which are known to flourish under high Corg flux. The estimated values of BFHP and BFOI were controlled mainly by the abundance of bolivinid species which are generally considered as opportunistic and shallow infaunal species, tolerant to low oxygen conditions. The statistical analysis (Q-mode cluster analysis) singled out four time intervals, each characterized by certain levels of oxygenation and food availability. Time interval 1 (8513–8300 cal BP) is characterized by a mixed fauna of oxyphilic taxa and taxa that live in suboxic environment, indicating the existence of a relatively eutrophic system with a well-oxygenated sediment–water interface. Time interval 2 (8300–8100 cal BP) records a deterioration of conditions on sea floor, testified by significant oxygen and biotic diversity decrease. Benthic foraminifer composition in Time interval 3 (8100–7000 cal BP) depicts environmental conditions still highly variable, yet with faunal indication of more stable conditions than during the previous interval. Finally, the benthic foraminifer assemblage of Time interval 4 (7000–3500 cal BP) is related to the high food supply and good bottom circulation. The data suggest a strong linkage between the quantity and quality of the organic matter supplies, and the diversity and composition of the benthic foraminifer faunas. Moreover, this study clearly demonstrates that vertical tectonic movements need to be taken into account when reconstructing the late Quaternary palaeoceanography of this region.

Santorini volcano has been the largest source of volcaniclastic sediment in the Eastern Mediterranean during the late Quaternary. A dozen cores from the Cretan Basin, south of Santorini, have sampled two megabeds that consist of gravity emplaced volcaniclastic sequences. The uppermost megabed U consists of a succession of five (U5-U1) base cut out turbiditic units. Lower megabed A is a single turbiditic event. Only the uppermost U2 and U1 turbidites are separated from the underlying beds by hemipelagic marls. The texture and composition of the U and A megabeds closely match the texture and composition of the fine, vitric ash of the "Minoan" deposits on Santorini islands, dating from about 3500 yr BP. These megabeds are therefore attributed to rapid accumulation of separate gravity flows fed by the "Minoan" eruption, except for the upper U2 and U1 turbidites deposited from subsequent gravity flows transporting eroded volcaniclastic sediments. With the exception of the margin south of Santorini, dozens of cores retrieved around the margins of the Cretan Basin have a continuous late Quaternary succession that shows no evidence for massive sediment remobilization into the deeper basin, including the passage of the "Minoan" tsunami. Extensive high-resolution 3.5 kHz records revealed the acoustic character, architecture and distribution of the U and A megabeds and four underlying late Quaternary volcanogenic megabeds in the Cretan Basin. The acoustic facies of megabeds are typical of megaturbidites and consist of an upper, transparent, lower velocity layer that corresponds to the fine-grained upper turbiditic silt and clay section and a lower, strongly reflective higher velocity section that corresponds to the lowest, coarser-grained base of the turbidite that is developed over a sharp erosional surface. Penetration of the high-resolution records reveals the existence of at least six megabeds. Correlation with core lithology and the physical properties of the various lithofacies, including down-core velocity profiles, has allowed us to determine the thickness and volumes of the upper four megabeds which are: U ≤ 9 m thick, volume 3.7 km3; A ≤ 25 m thick, volume 12.2 km3; B ≤ 22 m thick, volume 10.3 km3; C ≤ 15 m thick, volume 8 km3. These thick megabeds are the uppermost products of repeated explosive eruption of Santorini in the late Quaternary. Calculated sedimentation rates from and after the "Minoan" eruption are 9.4 m/1000 yr that rise to over 15.7 m/1000 yr if megabed B was also deposited during this eruption. © 2007 Elsevier B.V. All rights reserved.

The Gulf of Amvrakikos is one of several E–W grabens developed in the Middle Quaternary almost orthogonal to the tectonic grain of the external Hellenides in western Greece and is critically located at the termination of the Kefallinia transform fault linking the Hellenic subduction zone to the Adriatic-Dinaride collision lineament. The tectonic evolution of the Gulf and the response of sedimentation have been investigated based on 3.5 kHz and sparker profiles. The Holocene stratigraphy results from rising eustatic sea-level breaching the tectonic sill north of Preveza and inundating the braid plain of the Arachthos river, which then prograded across the northern Gulf following the formation of the maximum flooding surface. Older major transgressive surfaces are recognised in sparker profiles. Interpretation of these transgressions in terms of eustatic sea-level changes allows a chronology to be established and estimates to be made of neotectonic rates of subsidence. Two sets of neotectonic faults are present: reactivated NNE-trending mid-Tertiary thrusts of the Ionian zone and more active E–W trending faults. The sedimentary succession in the Gulf of Amvrakikos is the result of a complex interplay between eustatic sea level changes, the neotectonic creation of accommodation, and autocyclic delta distributary switching. The details of this process are resolved for the Holocene and the general sedimentation pattern established back to marine isotope stage (MIS) 8 (245–300 ka). In general, MIS 8 shows greater evidence of terrestrial deposition, compared with MIS 6 (130–190 ka) and especially MIS 2–4 (10–80 ka), when there was lacustrine deposition and some marine incursions at intermediate eustatic sea levels. This implies that regional subsidence has been taking place at least since MIS 8. In addition, changing sediment supply plays a role in overall sediment architecture, but is only well resolved for the Holocene, with higher rates of fluvial supply recognised in the mid Holocene.

A 30-m long piston core from the floor of Pantelleria Trough penetrated an 18 m thick volcaniclastic interval under- and overlain by hemipelagic sediments. The distribution and thickness of the interval is mapped in 3.5 kHz profiles across the trough. Core sediments have been analysed for grain size, carbonate content, detrital petrology, and physical properties such as bulk density and magnetic susceptibility. Chemical analyses of tephra and included minerals have been made by electron microprobe. The volcaniclastic interval is correlated with the youngest large explosive eruption on Pantelleria, the 50 ka Green Tuff ignimbrite eruption, on the basis of the sedimentation rate of overlying sediment, calcareous nannofossil and foraminiferal biostratigraphy, a calibrated radiocarbon age of 43–47 ± 2 ka (possibly infinite) in the underlying marls, and many similarities in tephra and mineral chemistry and abundance. The lower 8 m of the volcaniclastic interval consists of poorly sorted massive units of lapilli tuff, interpreted as resulting from the direct flow of a pyroclastic flow into the sea, with the energetic hyperconcentrated flows crossing the length of Pantelleria Trough and eventually “freezing” on the low gradients. The overlying 10 m thick turbidite probably developed from the dilute turbulent pyroclastic flow of the co-ignimbrite cloud and the resulting turbulent subaqueous flow eroded bioclastic material from the shelf and deposited a well-graded bed from sand through silt to mud. The poorer sorting of the volcaniclastic interval compared with the Green Tuff ignimbrite on land supports the concept that ignimbrite deposits are sorted by aggrading bed processes.

The southern Aegean Sea has undergone major subsidence as a result of back-arc extension during the Neogene. The details of this subsidence and the resulting sedimentation patterns have been examined in the Myrtoon basin and adjacent areas, including the south Evoikos, Saronikos and Argolikos gulfs, by comparing seismic stratigraphy and facies interpretation from multichannel seismic profiles with the stratigraphic and sedimentologic history of adjacent land areas. A detailed seismostratigraphy has been developed for the whole area in the late Neogene. The Messinian erosion surface is an important regional marker. Pliocene and early Quaternary markers are dated by comparison of marine transgressions with dated sections along the coast and dated volcanic rocks on islands. The region appears to have progressively subsided since the Miocene. Myrtoon basin and Saronikos Gulf were lake basins in the Messinian that were flooded to form deep-water marine basins during the basal Pliocene transgression. South Evoikos and Argolikos basins were progressively flooded during the Pliocene and early Quaternary. In most areas, deep-marine basins filled principally with hemipelagic sediment, but a submarine fan developed in the early Pliocene in the northern Myrtoon basin and fan deltas built into the basin from the east and southwest. Opening of marine ‘gateways’ as a result of subsidence led to enhanced oceanographic circulation and the formation of regional erosion surfaces at basin margins.

The distribution and stratigraphy of volcanic rocks around the island of Milos has been interpreted from seismic reflection profiles. A consistent seismic stratigraphy can be recognised in the major basins, which contain mostly hemipelagic to low-energy gravitative sedimentation interrupted only locally by mass-transport deposits, despite the proximity to volcanic islands. Volcanic rocks have a distinctive rather incoherent acoustic signature and in places overlie stratified marine sediment. Their age is inferred from position relative to the Messinian seismic marker and by correlation with volcanic episodes dated on land. Volcanic rocks underlie an area five times larger than the present outcrops of volcanic rocks on Milos and adjacent islands. The main phase of volcanism was of late Pliocene age. It locally overlies folded lower Pliocene strata. In places the volcanic rocks have been planed off by Quaternary coastal erosion surfaces and have subsequently subsided, at rates of 0.2–0.35 mm/yr. Basin margins appear to have been generally stable, probably as a consequence of the relatively shallow water depths. Volcano flank failure deposits do not appear to be a major component of the sedimentary architecture.

Piston cores from the Balearic and Herodotus Abyssal Plains in the Mediterranean Sea show that the Late Pleistocene to Holocene sedimentary sequence is dominated by turbidite muds. On each plain, one turbidite bed is conspicuous by its thickness, and this bed can be correlated basinwide on the basis of geochemical compositional analysis and its apparent correspondence with a distinct acoustically transparent layer on high-resolution seismic records. These megabeds on the two plains represent megaturbidites of very large volume (300–600 km3 each) and are shown by AMS radiocarbon dating to have been emplaced during the last low stand of sea-level at the height of the last glacial maximum. The megabed on the Balearic Abyssal Plain is derived from the southern European margin and is the main sedimentation event over the last 120 ka. It emplaced as much material as was deposited by smaller flows during the previous 25 ka. Sedimentation rate curves for the Balearic Abyssal Plain show that falling sea-level correlates with increased terrigenous deposition, and that gross sedimentation rates in the basin increased as sea level fell from 120–18 ka due to more frequent emplacement of distal turbidites. The Herodotus Abyssal Plain megabed is derived from the Libyan–Egyptian continental shelf west of the Nile Delta and was the dominant sedimentation event in this basin during the past 60 kyr. High-resolution seismic profiles from the Ionian and Sirte Abyssal Plains in the central Mediterranean also suggest possible low sea-level emplacement of megabeds in these regions. Available evidence suggests widespread emplacement of megaturbidites throughout the Mediterranean at the last glacial maximum. Although the triggering mechanisms for these events remain speculative, catastrophic destabilisation of the margin after a long period of accumulation with an increased rate of sediment supply is suggested.

Naxos disease is a recessively inherited stereotype association of arrhythmogenic cardiomyopathy with a cutaneous phenotype, characterized by peculiar woolly hair and palmoplantar keratoderma. The cardiomyopathy clinically manifests by adolescence and the symptomatic presentation is usually with syncope and/or sustained ventricular tachycardia of left bundle branch block configuration. We report the case of a 43-year-old man without any history of heart disease who was admitted to the hospital because of an episode of sustained ventricular tachycardia and troponin I elevation, in the absence of coronary artery disease. Diagnostic workup, including genetic assessment, revealed Naxos disease as the underlying cause. In this case, acute myocarditis seems to be the most plausible explanation for the nonischemic myocardial injury.

The early Holocene S-1 sapropelic sequence in the northwest Hellenic Trench has been studied in six piston cores from the Zakinthos and Strofadhes basins. The S-1 sequence, 0.7-3.5 m thick, consists principally of silt to mud turbidites, with rare, thick, disorganized, sandy turbidites. These lithofacies are described and compared with fine-grained turbidites from the literature. Petrographical data, including the abundance of organic carbon and planktonic microfossils, indicate that the principal source of sediment to the turbidites was from the continental slope. On the basis of composition and texture, five turbidite units can be correlated between the two basins. These basins are fed by separate but adjacent drainage systems. The apparently synchronous occurrence of turbidites in the two drainage systems suggests that the turbidity currents were seismically triggered. Some of the turbidites show poorly organized beds which may reflect the slump origin and the short (30 km) distances of travel. Turbidites were deposited more frequently in the S-1 sapropelic interval than in the over- and underlying sediments. Application of slope stability analysis shows that on the 8° slopes above the basins, a 10-cm-thick sapropel would have a factor of safety of about 2, and would fail with earthquake accelerations in excess of 0.08 g. The frequency of earthquakes likely to produce such accelerations is similar to the observed frequency of turbidites. The low strength of the sapropelic sediment makes it particularly susceptible to such failure. Similar thin-skinned slumping may be an important process for the initiation of turbidity currents in other environments where there are steep slopes or high sedimentation rates.

The Cyprus Arc System forms part of a well-defined, presently active, plate boundary and is a critical area for understanding the evolution of the Eastern Mediterranean Sea. The available seismic reflection profiles are utilised in order to establish the nature and origin of the main tectonic features of the arc, which include: 1. (a) The Cyprus Trench, displaying evidence of underthrusting and morphostructural features typical of subduction zones. 2. (b) The Pytheus Trench, associated with right-lateral strike-slip movement and connecting the western end of the Cyprus Trench to the Strabo Trench sector of the Hellenic Trench System. 3. (c) A predominantly transtensional fault zone connecting the easternmost part of the Cyprus Trench via the Baer Bassit overthrust zone in Syria to the Dead Sea Transform Fault System. 4. (d) A zone of complex deformation, involving thrust and transform elements, running from the Misis Mountains of southeast Turkey through the Kyrenia Range in Cyprus to the Gulf of Antalya and transected by roughly N-S major shears (notably the Cape Gelidonya-Anaximander Mountains strike-slip zone), which appears to form the western boundary of the present active system of the Cyprus Arc. The nature of the shallow structures associated with the Cyprus Arc is consistent with a geotectonic model involving some post-Miocene rotation of the South Anatolian-Cyprus Block, probably induced by “escape dynamics” resulting from continent-continent collision in eastern Turkey and the development of the Maras triple junction in southeastern Turkey. The alternation of plate boundary sectors respectively characterised by thrusting and strike-slip displacement suggests that the shallow crust in this part of the eastern Mediterranean is in a compartmented and relatively brittle state, allowing accumulated boundary stresses to be accommodated largely by displacements and deformation along secondary features.

Autonomy is a fundamental property for an intelligent virtual agent. The problem in the design of an autonomous IVA is that the respective models approach the interactive, environmental and representational aspects of the agent as separate to each other, while the situation in biological agents is quite different. A theoretical framework indicating the fundamental properties and characteristics of an autonomous biological agent is briefly presented and the interactivist model of representations combined with the concept of a semiotic process are used as a way to provide a detailed architecture of an autonomous agent and its fundamental characteristics. A part of the architecture is implemented as a case study and the results are critically discussed showing that such architecture may provide grounded representational structures, while issues of scaling are more difficult to be tackled.

Background. All cases of obstetric hysterectomies that were performed in our hospital during a seven-year study period were reviewed in order to evaluate the incidence, indications, risk factors, and complications associated with emergency obstetric hysterectomy. Methods. Medical records of 45 patients who had undergone emergency hysterectomy were scrutinized and evaluated retrospectively. Maternal age, parity, gestational age, indication for hysterectomy, the type of operation performed, estimated blood loss, amount of blood transfused, complications, and hospitalization period were noted and evaluated. The main outcome measures were the factors associated with obstetric hysterectomy as well as the indications for the procedure. Results. During the study period there were 32,338 deliveries and 9,601 of them (29.7%) were by cesarean section. In this period, 45 emergency hysterectomies were performed, with an incidence of 1 in 2,526 vaginal deliveries and 1 in 267 cesarean sections. All of them were due to massive postpartum hemorrhage. The most common underlying pathologies was placenta accreta (51.1%) and placenta previa (26.7%). There was no maternal mortality. Conclusions. Obstetric hysterectomy is a necessary life-saving procedure. Abnormal placentation is the leading cause of emergency hysterectomy when obstetric practice is characterized by a high cesarean section rate. Therefore, every attempt should be made to reduce the cesarean section rate by performing this procedure only for valid clinical indications.

Not only the occurrence of distinct organic-rich intervals (sapropels), but also the relative contents of key major and minor elements and isotopes in the sediments of the eastern Mediterranean, appear to be cyclic and to be astronomically associated. Interpretations of the environmental conditions leading to sapropel formation are based on results from sedimentological, micropalaeontological and geochemical studies of the dark-coloured layers and the cream/brownish sediments that occur above and below them. Part of the signal may be removed by early diagenetic processes. The extent and direction of these processes are ultimately controled by the amount and reactivity of organic matter. The interval of dark colour associated with a sapropel is often somewhat thicker than that defined by the >2% C org definition and usually has a sharp colour change at upper and lower boundaries. A grey so-called ‘proto-sapropel’ layer of variable thickness underlies most sapropel layers. A few centimeters above the most recent sapropel S1, is usually found a clear dark-brown layer 2–3 cm thickness is usually found, which has a diffuse, often mottled, upper boundary and a relatively abrupt colour transition at its lower boundary. The colour is characteristic of Mn oxyhydroxide enrichments. In the interval from the dark-brown layer to the visible upper S1 boundary, there is usually an increasingly red-brownish colour. The distinct upper manganese Marker-Bed has been related to the Santorini (Minoan) eruption in 3356±18 BP ( Bruins, H. J., & Van Der Plicht, J. (1996). The Exodus enigma. Nature, London , 382 , 213–214 ), but is more likely to be associated with a Basin-wide re-ventilation event induced by changing climatic (humidity) conditions. Using barite-Ba as a paleo-productivity indicator, enhanced fluxes, and hence increases in accumulation rates of organic carbon to the seafloor, must have occurred from approximately 9 to 5 ky BP. The perfect correlations between observed C org and calculated C org from the C org /Ba relation in the visible S1 interval, and the total lack of such correlation in the interval between the darkbrown layer and the visible S1 layer are remarkable. It seems, therefore, that S1 deposition lasted from 9 to 5 ky BP but the organic carbon for the upper part has been removed. The double barium peak visible in a number of sediments studied in high-resolution, may be related to the ‘Flooding’ of the Black Sea that occurred around 7150 BP (Ryan, W. B. F., Pittman, W. C., Major, C. O., Shimkus, K., Moskalenko, V., Jones, G. A., Dimitrov, P., Gorur, N., Sakinc, M., & Yuce, H. (1997). An abrupt drowning of the Black Sea shelf. Marine Geology, 138 , 119–126). Using various ‘proxies’, the (initial) occurrence of eastern Mediterranean sapropels appears cyclic and to be strongly related to the Monsoonal/Insolation Index. However, the relative value of an insolation maximum and initial C org content of the corresponding sapropel are not always related in a simple way. This again points to additional (possibly hydrographic) factors determining (the intensity of) sapropel formation. Understanding the mechanisms of sapropel formation and their subsequent preservation is not only necessary if our reconstructions of palaeoenvironmental conditions in the Eastern Mediterranean are to be improved, but may also assist in understanding the present-day situation and in forecasting possible future developments. The observed paleoenvironmental variations are discussed in a geochemical and environmental context, and are illustrated using typical examples from the eastern Mediteranean.

The central Hellenic Trench system, south of Crete, is a tectonically active region forming part of a complex geotectonic regime involving continental plate collision and convergence. Gravity and piston cores, together with seismic reflection profiles, provide evidence of significant variations in Plio-Quaternary lithology and sediment geometry that broadly reflect the morphologic diversity of this area and yield data important in the elucidation of analogous ancient sequences. Gravitite sediments are typically found in the trenches and deep basins, while suspensite sediments predominate on highs and in some perched basins. In detail, the trench floors are characterized by cyclic repetitions of gravitite sediments (in high proportions, comparable only to submarine fans elsewhere in the Mediterranean), thick diluted sapropels and hemipelagic calcareous oozes. The substantial core-to-core variations in this and other facies assemblages are attributed to the variety of sub-environments present within each depositional province. The Late Quaternary sediment sequences present in cores are well organized and display a cyclic stratigraphy that can be correlated with other eastern Mediterranean areas. Sedimentation rates deduced on the basis of this correlation are noticeably lower than in the western Hellenic Trench or the Nile Cone, probably because of the reduced supply of fine-grained terrigenous material to this area. Although there is a marked correlation between the Late Quaternary climatic-eustatic oscillations and the sediment types and rates, some of the overall variations in lithofacies patterns are best attributed to the tectonic mobility of the area. Seismic profiles reveal substantial regional variations in the geometry and organization of the Plio-Quaternary sedimentary fill in adjacent sectors of the trenches. The thickness of unconsolidated, undeformed sediment below the trench floor is also much smaller than that extrapolated from the Late Quaternary sedimentation rates computed from the cores. It is concluded that these variations in geometry and thickness of the sedimentary infill reflect different stages in the process of convergence and plate consumption. The differential removal of sediments from adjacent sectors of the trench floor is further interpreted as a discontinuous and diachronous process. The geometry, thickness and lithofacies represented in the central Hellenic Trench sequences appear more varied and complex than those reported from modern Pacific trenches and it is suggested that the Quaternary sediments of this region may furnish more appropriate examples of the deposition associated with alpine-type compressional settings than the sedimentary fill of Pacific-type trenches.