7 results on '"Wardell N."'
Search Results
2. First results from the CROP- 11 deep seismic profile, central Apennines, Italy: evidence of mid-crustal folding
- Author
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BILLI A., TIBERTI, M. M, CAVINATO, COSENTINO D., DI LUZIO E, KELLER JVA, KLUTH C, ORLANDO L, PAROTTO M, PRATURLON A, ROMANELLI M, STORTI F, WARDELL N*******., Billi, A, TIBERTI M., M, CAVINATO G., P, Cosentino, D, DI LUZIO, Emiliano, KELLER J. V., A, Kluth, C, Orlando, L, Parotto, M, Praturlon, A, Romanelli, M, Storti, F., and Wardell, N
- Subjects
Tectonics ,Sequence (geology) ,Paleontology ,Stage (stratigraphy) ,Metamorphic rock ,Phanerozoic ,Anticline ,Geology ,Crust ,Neogene ,Seismology - Abstract
The CROP-11 deep seismic profile across the central Apennines, Italy, reveals a previously unknown, mid-crustal antiform here interpreted as a fault-bend fold-like structure. The seismic facies and gravity signature suggest that this structure consists of low-grade metamorphic rocks. Geomorphological, stratigraphic and tectonic evidence in the overlying shallow thrusts suggests that this structure developed in early to mid- Messinian time and grew out of sequence in late Messinian– Pliocene time. The out-of-sequence growth may reflect a taper subcriticality stage of the Apenninic thrust wedge, which induced renewed contraction in the rear.
- Published
- 2006
3. The structural framework of the Peloponnese continental margin from Zakynthos to Pylos from seismic reflection and morpho-bathymetric data.
- Author
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WARDELL, N., CAMERA, L., MASCLE, J., NICOLICH, R., MARCHI, M., and BARISON, E.
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EARTHQUAKE zones , *TSUNAMIS , *THRUST faults (Geology) , *EARTHQUAKE aftershocks - Abstract
One of the objectives of the European project SEAHELLARC (SEismic and tsunami risk Assessment and mitigation scenarios in the western HELLenic ARC) was to identify the key elements controlling the geological structure of the Peloponnese continental margin in order to better understand the distribution of earthquakes in the area. Vintage multichannel seismic lines were reprocessed, interpreted and integrated with detailed morpho-bathymetric data and high-resolution single channel seismic data. According to the interpretation, most of the upper continental margin has been created within the former Alpine Gavrovo, Ionian and Apulian thrust units, including their Miocene to Quaternary cover and their Triassic salt-bearing formations. The Ionian thrust complex seems to have been continuously overthrusting the Apulian Ridge, itself characterised by strongly fractured acoustic basement features. Ductile and mobile Triassic evaporitic sequences are present in most of the major Ionian zone morpho-structures. The westward directed thrusts of the Ionian zone reached their final positions in Lower Pliocene and were followed by uplift of the ridges that is continuing in the present time. Previous compressional structures are being reactivated as normal faults with associated diapirism in the Triassic evaporites. NNE-SSW shear displacements related to trans-extensional motion may have activated "pull apart" basins with ENE-WSW normal faulting at their heads. This NNE-SSW dextral strikeslip motion agrees with the present anticlockwise rotation of the Peloponnese. The focal mechanism and the NNE-SSW distribution of aftershocks of a major earthquake in June 2008 along the Andravida fault define a major lineament that can be followed past the Katakolo Peninsula to the diapiric morpho-structures defining the eastern boundary of the Strophades basin. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
4. A new seismogenic model for the Kyparissiakos Gulf and western Peloponnese (SW Hellenic Arc).
- Author
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PAPOULIA, J., NICOLICH, R., MAKRIS, J., SLEJKO, D., MASCLE, J., PAPADOPOULOS, G., ANAGNOSTOU, CH., CAMERA, L., DASKALAKI, E., FASOULAKA, CH., FOKAEFS, A., FOUNTOULIS, I., GARCIA, J., GÜLKAN, P., MARIOLAKOS, I., POMONIS, A., SANTULIN, M., TSAMBAS, A., WARDELL, N., and YALÇINER, A.
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EARTHQUAKE hazard analysis , *SLOPES (Physical geography) , *GEOLOGICAL mapping , *EARTHQUAKE zones - Abstract
In order to define seismic hazard with sufficient accuracy required for engineering applications, we initiated a multidisciplinary geoscientific study offshore western Peloponnese, focusing on the Kyparissiakos Gulf. Multibeam swath bathymetry localised unstable coastal slopes, which were later investigated by high resolution seismic profiles. Sediments and crustal structures were studied by multi-channel seismic recordings and active larse-offsets seismic profiling. We established an onshore/offshore local seismic array that recorded 3500 micro-earthquakes in two months, and combined the results with historical and digital seismicity data in order to understand the active crustal deformation. These findings were further combined with geological mapping and tectonic observations from onshore Peloponnese and available offshore data. All this geologic and tectonic information was coupled with evidence from the analysis of historical and recent seismicity with the aim of identifying the seismogenic sources. We have defined nine seismogenic zones in western Peloponnese that are significantly different from those published in the literature. The new zonation addresses more accurately the deformation of the crust and sediments, and is the basis for a reliable seismic hazard analysis and seismic risk assessment. We identified a large area of the northern Peloponnese and the Ionian islands of Lefkas, Cephalonia, Zakynthos and Strophades, to be involved in a SW-ward oriented crustal extrusion, dominated by two major dextral deforming strike slip faults: Cephalonia and Andravida with their offshore prolongation. Some changes with respect to the Greek zonation in the literature have been introduced in the region surrounding the new nine seismogenic zones to reach a homogeneous cover of the whole Peloponnese. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
5. Seismic imaging of Late Miocene (Messinian) evaporites from Western Mediterranean back-arc basins
- Author
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Flavio Accaino, Nigel Wardell, Riccardo Geletti, A. Del Ben, M. Dal Cin, Angelo Camerlenghi, Arianna Mocnik, F. Zgur, DAL CIN, Michela, DEL BEN, Anna, Mocnik, Arianna, Accaino, Flavio, Geletti, Riccardo, Wardell, N., Zgur, Fabrizio, and Camerlenghi, Angelo
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010504 meteorology & atmospheric sciences ,Evaporite ,Geology ,Late Miocene ,010502 geochemistry & geophysics ,01 natural sciences ,Fuel Technology ,Geochemistry and Petrology ,Economic Geology ,Earth and Planetary Sciences (miscellaneous) ,Salt tectonics ,Tectonics ,Paleontology ,Stratigraphy ,Back-arc basin ,Magmatism ,Palaeogeography ,0105 earth and related environmental sciences - Abstract
An analysis of multichannel seismic reflection data was conducted focusing on the comparison between the Messinian Salinity Crisis (MSC) and Plio-Quaternary (PQ) evolution of the eastern Sardo-Provençal and northern Algero- Balearic basins and related margins in the West Mediterranean Sea. Both basins were completely opened during the MSC and their well-defined seismic stratigraphy is very similar in the deep parts. The primary difference between these two basins is due to their different pre-MSC extensional history, including the opening age and the stretching factors. These factors influenced the occurrence of post-MSC salt tectonics on these margins.
- Published
- 2016
6. The Messinian Salinity Crisis in the Westmediterranean Sea - Some Previous Results about the Messinian Events
- Author
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Flavio Accaino, Nigel Wardell, Arianna Mocnik, A. Del Ben, F. Zgur, R. Geletti, M. Dal Cin, Angelo Camerlenghi, EAGE, DAL CIN, Michela, Accaino, F., Camerlenghi, Angelo, DEL BEN, Anna, Geletti, R., Mocnik, Arianna, Wardell, N., and Zgur, F.
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Volcanism ,Diapir ,Messinian Salinity Crisis ,Tectonics ,Paleontology ,Mediterranean sea ,Continental margin ,West-Medterranean Sea ,Magmatism ,halokinesis ,Messinian Salinity Crisis, West-Medterranean Sea, halokinesis ,Geomorphology ,Palaeogeography ,Geology ,Sea level - Abstract
A large seismic dataset has allowed us to regionally study the West Mediterranean Sea with particular focus on the West Sardinia and South Balearic continental margins and adjacent oceanic basins. The main seismic and geological evidences are related to the presence of the Messinian Trilogy in the deep basins and lower slopes, and coeval erosional truncation on the intermediate and upper margins. During the deposition of the upper Messinian sequence (UU), a thin salt layer has been highlighted, thanks to the high resolution of recent profiles. This salt layer, precipitated during the initial re-filling of the Mediterranean Sea, has been correlated to an erosional surface on the lower slope inner the UU and interpreted as the effect of a temporary sea level drop. The underlying salt layer (MU) shows halokinetic deformations in the deep basins which started since the Upper Messinian and developed principally during the Pliocene, sometimes until the Present, as testified by sea bottom piercings. The halokinetics has affected by different intensity, on the base of its original thickness, of the sediments and water load, and of the proximity of the lower slopes, where the sliding of salt toward the deep basin determined compressive stress and enhancing diapirism.
- Published
- 2015
7. A structural and geophysical approach to the study of fractured aquifers in the Scansano-Magliano in Toscana Ridge, southern Tuscany, Italy
- Author
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Nicola Praticelli, A. Zaja, Andrea Bistacchi, Henry Robain, Nigel Wardell, R. Francese, G. Pasquare, Gianfranco Morelli, Francesco Mazzarini, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Francese, R, Mazzarini, F, Bistacchi, A, Morelli, G, Pasquarè, G, Praticelli, N, Robain, H, Wardell, N, Zaja, A, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,Geophysical imaging ,[SDE.MCG]Environmental Sciences/Global Changes ,Aquifer ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Groundwater exploration ,GEO/03 - GEOLOGIA STRUTTURALE ,Fractured rocks ,Earth and Planetary Sciences (miscellaneous) ,Geomorphology ,0105 earth and related environmental sciences ,Water Science and Technology ,Hydrology ,geography ,Hydrogeology ,geography.geographical_feature_category ,Geophysical methods ,Tectonics ,Tectonic ,6. Clean water ,Italy ,Ridge ,Geophysical method ,Fracture (geology) ,Fractured rock ,Groundwater ,Geology - Abstract
Fresh water availability has recently become a serious concern in the Italian Apennines, as various activities rely on a predictable supply. Along the ridge between Scansano and Magliano in Toscana, in southern Tuscany, the situation is further complicated by contamination of the nearby alluvial aquifers. Aquifers locally consist of thin fractured reservoirs, generally within low-permeability formations, and it can be difficult to plan the exploitation of resources based on conventional techniques. An integrated study based on geological data investigated the link between tectonics and groundwater circulation, to better define the hydrological model. After the regional identification of fault and fracture patterns, a major structure was investigated in detail to accurately map its spatial position and to understand the geometry and properties of the associated aquifer and assess its exploitation potential. The subsurface around the fault zone was clearly imaged using ground probing radar, two-dimensional and three-dimensional resistivity tomography, and three-dimensional shallow seismic surveys. The vertical and horizontal contacts between the different geological units of the Ligurian and Tuscan series were resolved with a high degree of spatial accuracy. Three-dimensional high-resolution geophysical imaging proved to be a very effective means of characterising small-scale fractured reservoirs.
- Published
- 2009
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