E. Manoutsoglou

Using Various Guidelines and Approaches for the Assessment of Marine Sediment Quality

The aim of the present study is to explore the implications of using different quality guidelines and approaches for marine sediment characterization. As a case study, the sediments of Souda Port, Crete, Greece, were examined in order to assess heavy metal contamination and to estimate anthropogenic contribution and potential adverse effects to aquatic environment, as well as to indicate feasible future management options. The concentration of six heavy metals (Co, Cr, Cu, Ni, Pb, and Zn) was determined and compared with different sediment quality guidelines (SQGs) and regional/national criteria established for dredged material characterization and management. In addition, the geo-accumulation index (Igeo) was calculated and the sediments toxicity and heavy metals bioavailability were determined. Based on the experimental data, it is deduced that Souda sediments are characterized as moderately polluted only in terms of Co, Ni, and Pb.

Deformation patterns in the southwestern part of the Mediterranean Ridge (South Matapan Trench, Western Greece)

Seismic reflection data and bathymetry analyses, together with geological information, are combined in the present work to identify seabed structural deformation and crustal structure in the Western Mediterranean Ridge (the backstop and the South Matapan Trench). As a first step, we apply bathymetric data and state of art methods of pattern recognition to automatically detect seabed lineaments, which are possibly related to the presence of tectonic structures (faults). The resulting pattern is tied to seismic reflection data, further assisting in the construction of a stratigraphic and structural model for this part of the Mediterranean Ridge. Structural elements and stratigraphic units in the final model are estimated based on: (a) the detected lineaments on the seabed, (b) the distribution of the interval velocities and the presence of velocity inversions, (c) the continuity and the amplitudes of the seismic reflections, the seismic structure of the units and (d) well and stratigraphic data as well as the main tectonic structures from the nearest onshore areas. Seabed morphology in the study area is probably related with the past and recent tectonics movements that result from African and European plates’ convergence. Backthrusts and reverse faults, flower structures and deep normal faults are among the most important extensional/compressional structures interpreted in the study area.

Chemical and physical characteristics in uncultivated soils with different lithology in semiarid Mediterranean clima

The aim of this study is to identify the chemical and physical characteristics in uncultivated soils derived from different parent materials under semiarid Mediterranean climatic conditions which favoured the formation of fragile soils. The current work is of great interest in the agriculture and environmental stakeholders for providing a “benchmark” of undisturbed soil quality regarding organic content and nutrients availability. Principal Component Analysis (PCA) was used as the primary tool to demonstrate the soil quality stage, regarding nutrient availability. The statistical analysis revealed that one of the major physicochemical characteristics such as cation exchange capacity (CEC) is controlled exclusively from mineralogy and not from organic matter. Mineralogy and bulk chemical analysis is directly related to soil parent material lithology. The availability of inorganic nutrients (macro- and micronutrients) is low and relatively identical to most of the soils. PCA shows the unusual correlation of K

Subsurface Structure of Tympaki Basin (Crete, Greece) Based on Well and Geophysical Data

Tympaki basin has been studied in the past years from a hydrogeological point of view. Whatsoever, less are known on the subsurface structure of the plain part of the basin in terms of sediments thicknesses and faults existence. A way of identifying in-ferred faults is the integrated use of geophysical and well-data which finally give an insight of the subsurface within a content of a well-established knowledge of the geo-logical regime of the study area. In this paper the use of 3D geological modelling technique is described as a mean to identify fault structures and horizon depths. The data used include the digital elevation model (DEM) of the area, the boundary sur-face between geologic formations and the litho-stratigraphic data from wells, geo-physical measurements of Vertical Electrical Soundings (VES) and Transient Electro-magnetic Method (TEM). The first step was to develop a 3D stratigraphic model that approximates the subsurface position of the Plio-Quaternary and the Neogene depos-its. The inferred faults came out from this model were cross-checked with the TEM measurements providing an updated subsurface structure. All the newly identified faults and along with the depth of stratigraphic horizons give finally an overall tecton-ic pattern of the Tympaki basin.

Imaging Folegandros Basin by Using Seismic Reflection Data from a Part of Seismic Line AEG-1

Seismic reflection data of the part of seismic line AEG-1 which crosses Folegandros basin in the south-central Aegean has been processed in order to image structures within this basin. The processing sequence included band-pass filtering for noise suppression, velocity analysis, tau-p filtering for multiple attenuation, zero phase deconvolution and post stack migration techniques. The seismic reflection method at Folegandros basin provided information about the geological structures at intermediate depths which is possibly related to tectonic elements and structures at greater depth. The evolution of Folegandros basin is explained by the action of wrench tectonics which can contribute to the understanding of multi - direction crustal- extension in the area.

Imaging of Alpine and Post-Alpine Formations Using ERT at Loutsa- Remeri Open Pit Mine, Scourta, Viotia, Greece

A geophysical survey carried out at Scourta plateau in Central Greece employed the electrical tomography method in order to image the interface between Alpine and Post-Alpine formations and estimate the thickness of Terra Rossa deposits. The later are crucial for TITAN-SA cement company open pit mine. This mine provides row materials for cement production. This survey is related with future extension plan of the existing Loutsa-Remeri open pit mine. Scourta is an active polje and is filled with a thick Terra Rossa deposit which is a row material for cement industry. The geophysical survey revealed two distinct layers, the upper is characterized by lower resistivity values (less than 20 Ωm), minimum thickness to the east (25 m) and maximum thickness at least 50 m and is attributed to Terra Rossa deposits. The underlying layer exhibits higher resistivity values (more than 70 Ωm) and is attributed to karstified carbonate relief. The variation of the polje depth is accosiated with tectonokarstic processes. The E-W direction fault system delineates the karstic structure and the N-S ridge in the east part of the survey area is delineated by N-S direction faults.

Salt Water Intrusion Imaging at Tybaki (Greece) Using Geophysical Methods

A geophysical survey was conducted at Tybaki, Crete, Greece in order to support the geological and hydrogeological studies of the existing phenomenon of seawater intrusion. This survey employed seismic refraction, transient electromagnetic (TEM) and geoelectrical methods. The later, consisted of Vertical Electrical Sounding (VES) and Electrical Resistivity Tomography (ERT). The objective of this survey was to image the saltwater intrusion at this area and map possible favorable sea water pathways. We present the combined interpretation of vintage geophysical data obtained under the research project MEDIS and the ClearWater project data. At Tybaki, the geophysical survey provided images of the saltwater intrusion which is present at the north west of the basin.

Void Detection at Chania Airport by Combining ERT and Borehole Data

A detailed geophysical survey was carried out at Chania airport located at the north-west part of Crete, Greece in order to detect cavities in carbonate rocks. This survey combines electrical tomography and borehole data from Chania airport where new buildings are planned to be constructed. The site mostly consists of recrystallized carbonate rocks belonging to Trypali unit. Electrical resistivity tomography applied in dense grids at Chania airport provided images of the subsurface which conducted a borehole program for the detection of karstic forms in the carbonates. At the area under investigation according to resistivity imaging as well as borehole and surface geological data, the formations are mostly characterized as highly fractured. The size of the existing voids ranges from 0.5m to 6m.

The Role of Geophysical Methods in Salt-water Intrusion Mapping for Strongly Karst Formations, a Case Study at Stylos, Crete

Geophysical methods are useful tools for mapping the boundary between fresh and saline water. A geophysical survey was conducted in order to study the mechanisms of saltwater contamination in a strongly karstic coastal area. The region of interest is located in Western Crete about 3 Κm from the seashore. Seismic and electrical resistivity methods, along with detailed geological mapping have been employed to study the complex geological structure of the area under investigation. Electrical tomography detected a low resistivity zone which is attributed to a saline water layer. From the combination of the geophysical and geological data, a depicted major normal NE-SW fault zone mainly causes the groundwater salinization.