Timing of Contractional Tectonics in the Miocene Foreland Basin System of the Umbria Pre-Apennines (Italy): An Updated Overview

Francesco Brozzetti,Lucina Luchetti,Daniele Cirillo

doi:10.3390/geosciences11020097

Francesco Brozzetti, Lucina Luchetti + Show 1 more

Open Access

https://doi.org/10.3390/geosciences11020097

Copy DOI

Abstract

A large dataset of lithostratigraphic and biostratigraphic data, concerning the Early-Late Miocene turbidite succession of the Umbria pre-Apennines, is presented and analyzed. The data come from the study of 24 sections that are representative of all the main tectonic units cropping out between the front of the Tuscan allochthon and the Umbria-Marche calcareous chain. The sections have been dated using quantitative calcareous nannofossil biostratigraphy and, wherever possible, they were correlated through key-beds recognition. Such a multidisciplinary approach allowed us to reconstruct the evolution of the Umbria foredeep over time and to unveil the chronology of compressive deformations by defining: (i) the onset of the foredeep stage in each structural unit, (ii) the age of depocenter-shifting from a unit to the adjacent one, (iii) the progressive deactivation of the western sector of the foredeep due to the emplacement of allochthon units, and (iv) the internal subdivisions of the basin due to the presence of foreland ramp faults or thrust-related structures. A further original outcome of our study is having brought to light the Late Burdigalian “out-of-sequence” reactivation of the Tuscan allochthon which bounded westward the foredeep, and the subsequent protracted period of tectonic stasis that preceded the deformations of the Umbrian parautochthon.

Highlights

It is widely recognized that, in a foreland basin system, the spatial-temporal distribution of sedimentary processes reflects the tectonic deformations which drove its structuring [1,2]
This paper aims to provide an overview of all turbidite successions referred, in the literature, to the Umbrian domain, giving useful chronological constraints to future research on the tectonics and geodynamics of the Tyrrhenian-Apennines system, focusing on the Miocene deformational stages
These data, which had already been calibrated by nannofossils biostratigraphy [26], were subsequently homogenized with the datasets reported in previous works dealing with the tectono-stratigraphic setting of the Mt Rentella [15], M

Summary

Introduction

It is widely recognized that, in a foreland basin system, the spatial-temporal distribution of sedimentary processes reflects the tectonic deformations which drove its structuring [1,2]. Such a close link between the evolution of the chain and the depositional events that occurred in the foredeep and the associated satellite basins is well documented in any stage of the Apennines orogenic system [3,4,5,6,7]. Within the pre-Apennine, the Meso-Cenozoic Umbria-Marche multilayer crops out only in correspondence of narrow culminations located in the Perugia Mts ridge (west of the Tiber river) and in the Gubbio and Mt Subasio doubly plunging anticlines (eastern Umbria, Figure 1)

Objectives

Methods

Conclusion