HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.Complex basin development in a wrench-dominated back-arc area: tectonic evolution of the Crati Basin, Calabria, ItalyTo cite this version: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Page 1 (1, *); Tondi, E.( 1) ; Mazzoli, S; 4(1) Dipartimento di Scienze della Terra, Università di Camerino, Italy 5 (2) Dipartimento di Scienze della Terra, Università di Napoli "Federico II", Italy 6 7 (*) corresponding author: e.mail: spinavincenzo@yahoo.it fax. +39 06. 61248020 8 now at: 9(1) Total Exploration and Production Italia, via Cornelia 498; 00166, Rome (Italy) 10 11 Abstract 12Field data and seismic reflection profiles of various resolutions, calibrated by deep well logs, 13 have been used to unravel the tectonic evolution of the Crati Basin (southern Italy). The study 14 area is located in the northern portion of the Calabrian Arc, a well-developed arc-shaped 15 feature of the circum-Mediterranean belts, consisting of a series of ophiolite-bearing tectonic 16 units and overlying basement nappes. NW-SE oriented left-lateral strike-slip faults exerted a 17 major control on the tectonic evolution of northern-central Calabria, from Middle Miocene to 18Lower Pleistocene times. Such faults, arranged in an en-échelon geometry and dissecting the 19 pre-existing Late Oligocene-Early Miocene orogenic belt, led to a structural setting including 20 major N-S striking synforms -as the offshore Paola Basin and the Crati Basin are interpreted 21 based on our results -separated by a broad antiformal ridge. Since the Middle Pleistocene, 22 both E-and W-dipping normal faults developed in the southernmost sector of the Crati Basin, 23 probably as a consequence of both uplift of the orogenic edifice and Tyrrhenian back-arc 24

A comprehensive sedimentological study was undertaken in the Miocene of the subalpine massifs and southern Jura (France) with the aim to constrain the evolution of process changes in third‐order sequences of peripheral foreland basins during the overfilled phase (i.e. sediment supply higher than accommodation space). Fieldwork analyses based on 35 sedimentological sections allowed the identification of four depositional models: wave dominated, mixed wave‐tide, river to tide and river dominated. The sections were dated using chemostratigraphy (i.e. marine strontium isotopic ratios), revealing three‐third‐order sequences between the Upper Aquitanian and the Langhian. Chronostratigraphical and sedimentological results document prominent and recurrent changes in depositional models along third‐order sequences: (i) in the earliest stage of the transgression, mixed‐energy coastal environments influenced by the local coastal morphology prevailed (in palaeo‐highs or incised valleys); (ii) during the course of the transgression, Gilbert delta deposits suggest a prominent steepening linked to a tectonic uplift in the proximal depozone (between the tectonically active frontal part of the orogenic wedge and the proximal foredeep). Instead, in the distal depozone (between the proximal foredeep and the proximal border of the flexural uplifted forebulge), deposits were characterized either by wave‐dominated or mixed wave‐tide environments and are likely eustatically‐driven; (iii) during the maximum flooding stage, water depth remained shallow below the storm‐weather wave base; and (iv) during the regression, the proximal depozone is characterized by the progradation of gravel‐rich fan deltas. In the distal depozone, mixed wave‐tide systems preceded the development of river to tidal depositional environments. These results were integrated and compared with facies models from other basin analogues worldwide. A model tackling the evolution of process changes within third‐order sequences (of the overfilled phase) of foreland basins is proposed, thereby improving sequence stratigraphic predictions in foreland basins.

Abstract. After more than a century of research, the chronology of the deformation of the external part of the Alpine belt is still controversial for the Miocene epoch. In particular, the poor dating of the foreland basin sedimentary succession hampers a comprehensive understanding of the kinematics of the deformation. Here we focus on the Miocene Molasse deposits of the northern subalpine massifs, southern Jura, Royans, Bas-Dauphiné, Crest and La Bresse sedimentary basins through a multidisciplinary approach to build a basin-wide tectono-stratigraphic framework. Based on sequence stratigraphy constrained by biostratigraphical, chemostratigraphical (Sr-isotopes) and magnetostratigraphical data between the late Aquitanian (~21 Ma) and the Tortonian (~8.2 Ma), the Miocene Molasse chronostratigraphy is revised with a precision of ~0.5 Ma. The Miocene Molasse sediments encompass four different palaeogeographical domains: (i) the oriental domain, outlined by depositional sequences S1a to S3 (~21 to ~15 Ma), (ii) the median domain characterized by sequences S2 to S5 (~17.8 to ~12 Ma), (iii) the occidental domain, in which sequences S2a to S8 (~17.8 to ~8.2 Ma) were deposited and, (iv) the Bressan domain, where sedimentation is restricted to sequences S6 to S8 (~12 to ~8.2 Ma). A structural and tectono-sedimentary study is conducted based on new field observations and the reappraisal of regional seismic profiles, thereby allowing the identification of five major faults zones (FZ). The oriental, median and occidental paleogeographical domains are clearly separated by FZ1, FZ2 and FZ3, suggesting strong interactions between tectonics and sedimentation during the Miocene. The evolution in time and space of the paleogeographical domains within a well-constrained structural framework reveals syntectonic deposits and a westward migration of the depocenters, and allows to establish the following chronology of thrust propagation at the western alpine front: (i) A compressive phase (P1) corresponding to thrusting above the Chartreuse Orientale Thrust (FZ1), which was likely initiated during the Oligocene. This tectonic phase generated reliefs that limited the Miocene transgression to the east; (ii) the ~W-WNW/E-ESE-directed compressive phase (P2) involving the Belledonne basal thrust, which activated the Salève thrust (SAL) fault and successively FZ2 to FZ5 from east to west. Phase P2 deeply shaped the Miocene palaeogeographical evolution and most probably corresponded to a prominent compressive phase at the scale of the Alps during the early to middle Miocene (between 18.05 +/- 0.25 Ma and ~12 Ma). In those ~6 Myr, the Miocene sea was forced to regress rapidly westwards in response to westward migration of the active thrusts and exhumation of piggy-back basins atop the fault zones; (iii) the last phase (P3) of Tortonian age (~10 Ma), which likely implied a significant uplift (350 m minimum) of the Bas-Dauphiné basin, whereas horizontal motions prevailed within the Jura Mountains.

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