RICERCA ITALIANA     

Synthetic crustal model in Sicily from integration of geological and geophysical data

Università degli Studi di Palermo

Abstract

Main objective of this program is the study of the interaction between the surface and deep crustal structures of the Sicily and its marine extension chain system with the aim to improve the knowledge of the mechanisms that control the geodynamic evolution of the Central Mediterranean.
Mains problems remain still unsolved, among these:
- depth of the decollement plains;
- crustal characters (thickness, density, geodynamic heritage);
- depth of the (African) basement;
- involvements of the basement on the chain;
The three research units involved in the project aim to contribute to the results with a multidisciplinary approach integrating available and/or new geological and geophysical data that will be acquired in different sectors of the Sicily system using different methodologies as:
- Field geology;
- Structural stratigraphic analyses;
- Balanced cross-sections;
- Seismo-stratigraphic analyses;
- Reprocessing of NV seismic profiles;
Reinterpretation of magnetometric, gravimentric and refraction seismic profiles data;
Quantitative analisys of the tectonic (shortening and extension) processes that control crustal subsidence and/or uplift;
Main objectives are:
- To verify the involvement of the crystalline basement in the chain building;
- To determine the depth of the decollement levels of the main carbonatie bodies;
- To verify the crustal meaning of some >>>

Principal Investigator

Raimondo CATALANO Università degli Studi di PALERMO

Research Objectives

The main aim of the project is to improve the knowledge of the mechanisms that control the dynamic evolution of the central Mediterranean area, which is characterise by subduction of both continental and oceanic crust, with the study of the relationships between shallow tectonic units and deep structures of the Sicilian Chain and its marine prolongation. In particular, are essential steps of the project the identification of the most significant crustal characters (basement and Moho deep, thickness and lateral variation and so on), their integrations with stratigraphic and structural data with the aim to construct a synthetic crustal model across Sicily. This model will be of fundamental importance in planning the future acquisition and interpretation of a NV high-penetration seismic profile that will be shot across central Sicily (farther continuation of the Crop project).
In this frame, the single Researches Units aims would be as follows:
1) Palermo. Research unit coordinate by Prof. Raimondo Catalano. Balanced geological cross-section from the southern Tyrrhenian Sea to the Sicily Channel across Sicily mainland, based on the integration of meso-structural and seismostratigraphic data. Quantitative analyses of the kinematic of the tectonic processes (shortening, extension) responsible for subsidence and/or uplift of the different sectors of the collisional system outcropping in Sicily. Backstripping of the geological cross-sections and their palinspastic >>>

First Results

New stratigraphic and structural data in the study area; Seismic profiles reprocessed with advanced tools (i.e. tomographic analyses, 2D velocity and density analyses ). Data base of seismic profiles and drilled wells for oil research. Interpretation of seismic profile; balanced cross-section.Quantitative map of crustal deformation in the northern Sicily offshore. Quantitative paleogeographic maps, assessment of the role of inherited pre-orogenic lithosphere in the Neogene to Recent tectonic evolution in the different zones of the collisional and subduction system. 3D density and velocity models obtained by the tomographic analysis. Reprocessing and bi-dimensional reinterpretation of the low and high sampling frequency-crustal seismic profiles. Geological and geophysical modelling of the study area. Determination of the chain load and/or subduction processes in the Sicilian foredeep evolution.

Timescale

24 months

National and international background

Neogene to Quaternary central Mediterranean tectonics are controlled by a complex interplay of plates within a frame of convergence between Africa and Eurasia. The relative movements of these crustal blocks resulted in the formation of collisional (e.g. Apennine-Maghrebian chain) and subduction systems, which developed close to the extensional areas (e.g. Tyrrhenian Basin). The most accepted geodynamic models for the Central Mediterranean area postulate the formation and evolution of collisional and subduction systems genetically linked to the NW-dipping subduction of the Adria-Ionian plate underneath the Corsica-Sardinia block (Malinverno and Ryan, 1986; Patacca et al., 1990; Faccenna et al., 1996). The roll-back and retreat of this plate is believed to be the cause for the extensional tectonics that lead to the opening of back-arc basins, younger toward the S-E (Gueguen et al., 1998 and references therein). Presently, the seismicity west of the Calabria and southern Apennines (Gasperini et al., 1982) as well as the calc-alkaline affinity of the Aeolian-arc volcanism (de Astis et al., 2003 and references therein) suggest the occurrence of a NW-dipping subduction of the Ionian plate underneath Calabria (Cernobori et al., 1996; Doglioni et al., 1999; Catalano et al., 2002). Subduction and wedge accretion are synchronous with back-are extension in the Tyrrhenian.
The crustal sector extending across Sicily between the Sardinia Block and the Pelagian-Ionian area is a >>>