1,354,128 research outputs found
Autoecology of Verrucaria baldensis, a shade-adapted, endolithic lichen from the Trieste Karst (NE Italy).
No full textAdvanced processing of seismic data in Central Adriatic Basin to highlight Plio-Quaternary features
No full textThe geological setting of the Central Adriatic Basin is characterized by the presence of several sedimentary features originated during the growing up of the Dinaric and Apennine Chains. The migration of these fronts towards the axis of the Adriatic Sea, determined the Plio-Quaternary clastic sequence (Channel et al., 1979). During the Lower Pliocene, the migration of the Apennine Chain produced the west-ward tilting of the Adriatic foreland, causing a sedimentary wedge and a thickness of sub-horizontal Pliocene deposits, covered by the Quaternary prograding sequence.
These last are visible on the seismic profile ADRIA 95 located in the western portion of the Central Adriatic Basin. The profile was partially processed by Geletti et al. (2008) and now we decided to improve the elaboration of the seismic signal to better define the reflectors characterizing the Plio-Quaternary sequence, the recent deformation of the shallower layers and some bright spots, probably associated to gas presence.
We applied a standard processing flow, testing in particular multiple reflections attenuation methods, pre-stack deconvolution techniques, stacking velocity analysis and depth migration within the first 2 sec TWT of the recording trace. The bright spots have been focused by seismic attributes analysis
RELATION BETWEEN RECENT TECTONICS AND MESOZOIC INHERITED STRUCTURES OF THE CENTRAL-SOUTHERN ADRIA PLATE
No full textRecent tectonics and Mesozoic inherited structures in the offshore of the Central-Southern Adria Plate
No full textGeophysical exploration of the West Sardinian continental margin and Sardo-Provençal oceanic basin (West Mediterranean Sea)
No full textGeophysical exploration of the West Sardinian continental margin and Sardo-Provencal oceanic basin (West Mediterranean Sea).
Del Ben A.1, Geletti, R.2, Zgur F.2, Brancatelli G.2, Camerlenghi A.2, Dal Cin M.2, Fais S. 3,
Forlin E.2, Lanzoni A.1, Romeo R.2
1 Dipartimento di Matematica e Geoscienze, Università di Trieste.
2 Istituto Nazionale do Oceanografia e di Geofisica Sperimentale OGS, Trieste.
3 Dipartimento di Ingegnaria Civile, Ambientale e Architettura, University of Cagliari
Corresponding author: [email protected]
Keywords: West-Sardinian margin, Sardo-Provencal Basin, Seismic reflection, Messinian, Evaporites
The Sardo-Provencal Basin and its eastern continental West Sardinian margin represents one of the less explored Italian sea. During the year 2010 the Explora acquired a new geophysical dataset (W-Sardinia_2010) represented by seismic reflection and chirp profiles and Multibeam and Magnetic data. The dataset acquisition was designed on the base of results provided by previous seismic profiles of the MS (Mediterranean Sea), CROP (CROsta Profonda) and ViDEPI (Visibility of Petroleum Exploration Data, public data available in the Sardinian offshore, near the shoreline) projects. Integration of all the different dataset allowed us to interpret the main geological structures produced during the Upper Oligocene-Lower Miocene, when the rifting phase was followed by the oceanic opening of the West Mediterranean Sea. On the continental margin seismic waves have explored the whole sedimentary sequence, reaching the geological basement and showing the horst and graben system produced by the extensional tectonics (Geletti et al., 2014; Dal Cin et al., 2016; Del Ben et al., 2018).
On the oceanic abyssal plain the MS and CROP profiles depicted some deep reflectors, generally ascribed to the top of the basaltic basement, while not good information is available about the Moho reflector. The new W-Sardinia_2010 dataset, due to its higher resolution, highlights very clearly the Messinian evaporate sequence, characterized by the typical Messinian trilogy (Rehault et al., 2004).
The evaporate sequence is represented by i) a high amplitude stratified upper unit (UU), of mainly gypsum lithology, ii) a transparent salt unit (MU for Mobile Unit), characterized by strong halocinetic tectonics, and iii) a stratified lower unit (LU), never crossed by boreholes, probably also represented by gypsum. This trilogy gradually onlaps the lower continental slope, disappearing toward east, substituted by a marked erosional truncation (MES, for Margin Erosional Surface: Lofi et al., 2011) representing a variable hiatus, locally evident also in the Sardinia onshore.
The Plio-Quaternary sequence, clearly depicted by the seismic reflection, was highly deformed, especially during the Lower Pliocene, by halocinetics. Sometimes this process is still active, producing some circular structures in the sea bottom, which are well imaged in detail by the chirp and multibeam data.
The different resolution of the available data represents the best condition to study the whole sedimentary sequence and to correlate deep structures with their local effect on shallow youngest sediments.
References
Dal Cin M., Del Ben A., Mocnik A., Accaino F., Geletti R., Wardell N., Zgur F. & Camerlenghi A. (2016) - Seismic imaging of Late Miocene (Messinian) evaporites from Western Mediterranean back-arc basins. Petr. Geosci. 22, 297–308.
Del Ben, A., Mocnik A., Camerlenghi A., Geletti R., Zgur F., 2018. – 9.A-D- Western Sardinia. In: J. Lofi, Ed., Seismic atlas of the Messinian Salinity Crisis markers in the Mediterranean sea. Volume 2. - Mem. Soc. geol. fr., n.s., 2018, t. 181, and Commission for the Geological Map of the World, 32-35.
Geletti R., Zgur F, Del Ben A. , Buriola F. , Fais S., Fedi M., Forte E., Mocnik A., Paoletti V., Pipan M., Ramella R.,. Romeo R., Romi A. (2014) - The Messinian Salinity Crisis: new seismic evidence in the West-Sardinian Margin and Eastern Sardo-Provençal Basin (West Mediterranean Sea). Marine Geology, 351, 76–90.
Lofi, J., Deverchère, J., Gaullier, V., Gillet, H., Gorini, C., Guennoc, P., Loncke, L., Maillard, A., Sage, F., Thinon, I. (2011). Atlas of the Messinian seismic markers in the Mediterranean and Black Seas. Memoir Societe Geologique de France n.s. 179 and World Geological Map Commission (72 pp.).
Rehault, J.P., Boillot, G., Mauffret, A., 1984. The Western Mediterranean Basin geological evolution. Marine Geology 55, 447–477
THE MESSINIAN SALINITY CRISIS IN THE WEST-MEDITERRANEAN BASINS: COMPARISON BETWEEN TWO RIFTED MARGINS
No full textIn this work we present a comparison between two seismic datasets acquired by the oceanographyc research vessel OGS-Explora through the passive margins of the West Mediterranean sea: the West Sardinia continental margin of the Sardo-Provencal basin (WS10 dataset acquired in 2010) and the South Balearic continental margin of the Algerian basin (SF2012 dataset, acquired in 2012 within SALTFLU project).
The West Sardinia margin was originated by the Oligocene-Early Miocene breakup of European plate followed by the drift of the Sardinian block and the southern French margin; the Algero-Balearic basin opened later respect the Balearic basin, dating its oldest oceanic crust 16My following the rift of the Kabylide thrust belt (Muffret et al., 2004 and cited literaure).
Although the margins are different in age and geodynamic histories, here we intend to focus on differences and analogies concerning the geological features that characterize the Messinian and Post Messinian period, starting from the availability of already processed and interpreted seismic dataset of Western Sardinia (Geletti et al., 2014) and of processed by OGS and partly interpreted profiles of South Balearic margin.
In particular this approach should allow us to correlate the Messinian and Plio-Quaternary units that deposited in the West Mediterranean.
The comparison let to make considerations about the seismic facies of the Messinian sedimentary sequence that characterize the basinal domain and the slope of the North Algerian margin; analogies with the seismic facies of the Upper evaporite Unit recognized in the Sardo Provencal basin have been observed, represented by a thick well stratified package of high amplitude reflectors and intercalation of transparent layers. Observation about deformation structures mainly due to salt tectonic activity will be presented, basing on the already identification by Camerlenghi et al., (2009), of different kind of salt-induced abyssal plain sediment deformation.
Basing on the fact that there are lack of information in this sector of Western Mediterranean due to the absence of calibrating boreholes, this work could be a starting point to a major comprehension of the distribution of the Messinian Salinity Crisis processes within the basins of the Mediterranean sea
Seismic signature of Messinian event in the Mediterranean basins
No full textThe MSC, even if it is well documented in the whole Mediterranean Sea by several different seismic markers, is a still open question. The interpretation of the seismic signatures let to distinguish alternated phases of exposure and flooding of the different basins which often result to be hardly correlated to one another.
In the Adriatic basin and in the Sicily Channel the Messinian layer, where it is not replaced by an erosional surface, is present as a thin evaporate layer mainly constituted by Gessoso Solfifera formation. The Messinian trilogy has been observed only in the deep Balearic Basin, while in the Ionian and Levantine Basins it shows a mainly salt seismic facies.
The presented seismic data aim to contribute to the recognition of the different seismic facies which characterize the different units; their comparison could improve the comprehension of the processes that affected the Messinian events in the Mediterranean region, specially because of the critical lacking of boreholes
Seismic Analysis of Gas Accumulation in the Italian Offshore
No full textThe Apennine-Maghrebides foreland offers very different geological settings favouring gas accumulation within permeable horizons, depending by lithology and tectonic structures. In this paper we analyze the different relationships that may exist between the deep structures and the presence of gas in the Plio-
Quaternary sediments. Processing techniques (AVO and complex attributes analysis) and geological interpretation of some deep crustal seismic profiles in the Italian offshore, let us to make a qualitative study of gas presences finding their correlations with deep structures
Satellite imagery elaboration (aster sensor, terra satellite), in order to map rock distribution in extreme areas. the Prince Albert mountain chain (Victoria land - Antartica)
No full textThe present paper is a first attempt to use Remote Sensing and GIS methodologies in order to draw a rock distribution map in a extreme land as Antarctica. To this aim we elaborated an ASTER sensor image (Terra satellite). This sensor records medium resolution satellite images (from 15 m to 90 m pixels) in 14 different bands (from visible to thermal infrared). In the scientific community ASTER data represent a new tool in order to create land use maps, thermal distribution maps and 3d models of the territory. The adopted methodology is applied to a training area in Prince Albert mountain chain (Trans Antarctica Ridge – Victoria Land – Antarctica). We checked the spectral response of the satellite image pixels; then we estimated the kind of rock by the presence of different minerals in it. We did this comparing the reflectance values of the satellite image pixels with the one recorded in laboratory on each mineral in the different wavelengths corresponding to the ASTER sensor 14 bands.
In order to control our estimation, we used a geologic map of the same area. This one was drawn within the framework of the Italian National Research Program in Antarctica (PNRA). We choose a ASTER sensor satellite scene recorded in the period of maximum ice cover on the land, in order to grant a minimum outcrop in the case of an eventual manual check in Antarctica
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