RICERCA ITALIANA     

Integrated methodologies (organic matter dispersed in sediments, fluid inclusions, clay mineralogy and geochemistry, fission tracks and U-Th/He ages) to unravel the tectonic/sedimentary burial and exhumation in the southern Apennines (Calabria-Lucania border) and eastern Sicily (sedimentary fold-and-thrust belt)

Università degli Studi Roma Tre

Abstract

The aim of this research program is to define the THERMAL EVOLUTION of some of the main tectonic units of the APENNINE-MAGHREBIAN OROGEN. They are exposed in the SOUTHERN APENNINE and EASTERN SICILY, and lie in different structural positions in the orogenic wedge. The investigations will put NEW QUANTITATIVE CONSTRAINTS to define a model of GEODYNAMIC EVOLUTION of the orogen.
The research will be focussed on the study of:
- sedimentary and metamorphic successions that are related to the Ligurian Complex exposed in the Southern Apennine, at the Calabria-Lucania border;
- the sedimentary portion of the fold-and-thrust belt that crops out in Eastern Sicily, from the inner Sicilide Units to the external units, and the related syn-sedimentary successions.
In detail, investigations will concern:
- the area to the North of the Pollino mountain chain (Calabria-Lucania border) on the Frido Unit, belonging to the metamorphic complex, and on the non-metamorphic North-Calabrian Unit; sampling transects will be located in areas comprised in S. Severino Lucano, S. Costantino Albanese, and Viggianello topographic maps.
- a North-South transect through the sedimentary fold-and-thrust belt in Eastern Sicily between S.Agata di Militello and Ramacca villages (from Nebrodi Mts. to the North, to Iblei Mts. to the South).
The proposed methodological approach is multisciplinary and was originally developed for hydrocarbon exploration purposes >>>

Principal Investigator

Sveva CORRADO Università degli Studi ROMA TRE

Research Objectives

This research program's PRIMARY GOAL is reconstructing and comparing the THERMAL EVOLUTION of sedimentary and low/medium metamorphic grade successions of the Liguride complex, exposed at the Calabria-Lucania border in southern Apennine, of the sedimentary portion of Eastern Sicily's fold-and-thrust belt, and of related syn-orogenic successions.
The goal will be achieved by creating THERMO-STRUCTURAL MODELS by means of software applications (e.g., Basin Mod1D, Get1, SEbe3, AFTSolve) that jointly elaborate data from stratigraphic-structural and paleo-thermometric databases. The knowledge from the study of the examined units' thermal evolution will be then integrated with that on the Apennine-Maghrebian orogenic system. This will allow to put new constraints for the definition of a geodynamical evolution model of the orogen.

The achievement of the primary goal will derive from the accomplishment of the following SPECIFIC OBJECTIVES:
1. Quantifying maximum BURIAL hence maximum SEDIMENTARY and/or TECTONIC LOAD the studied successions underwent. This is obtained by using geothermometers based on clay minerals, on maturity indicators of the organic matter dispersed in sediments and on fission tracks. These indicators allow constraining the burial maximum temperatures. In this context we will attempt a direct correlation. The parameters are: vitrinite reflectance (Ro%, Stach et al., 1982); Thermal Alteration Index (Staplin, 1969); composition of >>>

First Results

Assessment of available data; further focusing on:
- open issues;
- major interest areas for the geological-structural investigation and sampling.Expected partial results for this phase of the project are:
• definition of geometric and kinematical features of the main structural elements delimitating the different investigated stratigraphic-structural units;
• preliminary elaboration of new meso-structural data acquired along the tectonic contacts and their integration to available databases;
• construction of preliminary geological-structural sketches and maps and geological sections;
• stratigraphic-structural samples contextualization.At the end of this phase laboratory analysis results will be available. Analytical tables, plots and - when needed - photos will be produced. The following specific papers will be also provided:
- frequency histograms of fluid inclusions microthermometry, subdivided by tectonic unit and deformation event; Tm/Th diagrams for identifying inclusions populations containing different fluids;
- Ro% frequency histograms and correlation table between Ro% and T.A.I. data;
- XRD patterns; illite crystal size distribution frequency diagrams and correlation tables of different mineralogical parameters;
- time-temperature paths and distribution of fission tracks lengths in the different investigated units;
- updates to the sediment's thermal evolution indicators database.In >>>

Timescale

24 months

National and international background

In the last 30 years, the thermal and burial history quantitative reconstruction of sedimentary successions that make up fold-and-thrust belts represents one of the major goals in the interdisciplinary researches of basin analysis (Allen & Allen, 1993 and references therein, Dorè et al., 1993). This type of research includes the integration of stratigraphic, structural, petrographic, and petrophysic data (for example, thickness of sedimentary successions and distribution of lithofacies, style and kinematics of deformation, composition and geotechnical features of lithotypes) (Van Hinte, 1978) with thermal evolution data from both inorganic fraction analysis (e.g., fission tracks, fluid inclusions, clay mineralogy and geochemistry, U-Th/He dating) and of the sediment's organic fraction (e.g., organic matter maturity) (Sholle & Schluger, 1979). Since the early 70s, using multidisciplinary databases of this kind, researchers proposed a number of modelling strategies for sedimentary sequences of undeformed basins; this also encouraged the study of thermal regime perturbations occurring in sedimentary units involved in orogenic processes (Lerche, 1990). In the beginning, these researches produced one-dimensional models (Furlong & Edman, 1984; Oxburgh & Turcotte, 1974); later, more refined two-dimensional models were created (Endignoux & Wolf, 1990; Shi & Wang, 1987; Grigo & Schmalholz, 2003) that also allow defining the entity of the tectonic and sedimentary load and determining >>>