RICERCA ITALIANA     

Mesozoic rifting events in the Central Mediterranean: paleogeography and tectonic evolution

Università degli Studi di Camerino

Abstract

The Mesozoic rifting events of the central Mediterranean area will be studied with a combined stratigraphic, petrologic, kinematic, paleotectonic and paleoenvironmental approach. The main goal is the elaboration of a quantitative kinematic model, based on finite eluer rotation, in the framework of Pangea break-up. This important event started in middle-upper Triassic, as shown by the magmatic and stratigraphic record of the Central Atlantic passive margin, and was extended, probably through the Apenninic-Magrebid chain, into the Mediterranean area. The study of the thick Mesozoic succession of the Apenninic-Magrebid chain, as well as the study of the outcropping deep crustal, mantle and oceanic rocks is crucial in order to correlate the rifting events that occurred in the Atlantic and Mediterranean areas.

Stratigraphic, sedimentologic, biostratigraphic, structural and petrologic data will be collected in order to: evaluate the subsidence, date and correlate the tectono-sedimentary events, reconstruct the paleoenvironments, recognize and analyse the basin margins, determine the paleostructures associations, evaluate the paleodomain widths, determine with isotopic geochronology techniques, where possible, the thermal history of the crust.

The objectives of this project are to: i) determine the relative positions of the original continental masses, and to evaluate the mechanism and magnitude of lithospheric stretching due to the rifting events ii >>>

Principal Investigator

Eugenio TURCO Università degli Studi di CAMERINO

Research Objectives

The main goal of this project is to contribute to the study of the Mesozoic rifts of the central Mediterranean region, from the stratigraphic, petrologic, structural, kinematic and paleoecologic perspectives. It should also lead to the formulation of a paleotectonic model of the process of fragmentation of Pangaea during the Triassic and the lower Jurassic. In order to reach this goal within the scheduled time, it is required a strong coordination between research units, which will involve specific themes in selected areas and use of commonly accepted methods. New data and interpretations will be collected in a common database, accessible by all participants. This aim of collaboration and data sharing is fully agreed with all research units.
The initial stage of fragmentation of Pangaea [Ladinic-Carnic] is coeval with an important stratigraphic and magmatic event that affected the whole Central Atlantic region, the Morocco meseta and the Mediterranean region (Veevers, 1989). Starting from this time, a composite system of rifts formed in eastern N. America, in the Atlas and in the western Mediterranean. In this context, the Apenninic-Maghrebian belt, with its important Mesozoic successions, represents the easternmost segment of the rift system. A systematic study of the Mesozoic domains of this belt will contribute to the determination of the relative motions between north and south Pangaea during the rifting event and will constrain boundaries and kinematics of the >>>

First Results

Estimation of bibliographic data availability and usefulness of these. Determination of needed new data and selection of study areas.The expected partial results consist of: stratigraphic sections related to the Triassic-Jurassic sequences of the studied areas; cartographic documents related to the facies distribution and paleoescarps; maps of paleofaults of the central Atlantic area, the Atlas and the Southern Alps; the determination of the relationship between blastesis and deformation; a data base for the data available in literature and the data collected from the Research Units involved in the project.Expected partial results consist of: subsidence curves of the main Triassic-Jurassic sequences; determination of beta factor; balanced cross sections; Adriatic paleomargin width evaluation at the end of Jurassic rifting; map of the continental faunas distribution; synthetic map of the Jurassic and Triassic paleostructures with the directions of extension; P-T-t-D diagrams for two deep crustal and mantle sections of the Calabrian Arc; kinematic model and paleogeographic maps of the rifts evolution.

Timescale

24 months

National and international background

Incipient break-up of Pangea took place in the upper-middle Triassic with a wide stratigraphic and magmatic event (Manspeizer, 1988; Veevers, 1989; Schilische, 1993). This event was extended, probably through the Appeninic-Magrebid chain, in the Mediterranean area. The Apenninic-Magrebid chain is characterized by a thick Mesozoic succession, and the Triassic and Jurassic units of this succession record the rifting events. The knowledge of these events, in the Pangea break-up framework, is crucial in order to reconstruct the paleogeographic and paleotectonic setting of the Central Mediterranean area.

The Apennines-Magrebid domain is considered as part of the southern-eastern margin (African and Adriatic-Apulian margin) of the Ligure-Piemontese oceanic basin opened from middle-upper Jurassic. The restoration of the Adriatic margin, in spite of the wide existing geologic literature, is difficult for the following reasons: i) there is uncertainty on the shortening of the chains; ii) the coincidence between the direction of the neogenic shortening and the direction of the Jurassic extension; iii) the superposition of the recent Tyrrhenian extension; iv) the lack of data, either in outcrops or in wells, concerning the basement of the Mesozoic cover. The latter do not permit to evaluate directly the nature of the basement and its role in the Mesozoic rifting events. In spite of the extensive work led for the realization of the CROP (CROsta Profonda) project, the role >>>