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In this study, we focused on the formation and preservation processes of colluvial sedimentary breccias within an extensional context. The breccias studied in this work (from Crete and the Pyrenees) are characterized by poorly sorted polygenic deposits of highly angular carbonate clasts whose size ranges from pebbles to blocks measuring several millimeters to several meters. This study shows that the colluvial sedimentary breccias were formed during extensional tectonics and are spatially associated with large-throw normal fault. They are related to the creation of a substantial topography in the footwall of the normal fault followed by its collapse on the hanging wall, leading to fast sediment accumulation and preservation. These breccias are organized, with pebble- to cobble-sized clasts near the slope of the fault while the mega-clasts, such as boulders and blocks, are preserved away from the slope. Such a clast size organization is indicative of a dry rockfall process and is opposite to that of alluvial fan systems dominated by gravity process involving water. This study also revealed that the breccias from the NE of the Pyrenees, encountered on both flanks of the Bas Agly syncline and previously attributed to the Lower Cretaceous, are related to a first phase of extension during the Upper Jurassic.

The environment of the Marseille basin in the Early Pleistocene was reconstructed through a multiproxy study of fluvial tufa deposits. Palaeomagnetic measurements revealed the Jaramillo subchron and dated the tufa to within the 0.8–1.5 Ma interval, probably between 0.9 and1.2 Ma. Sedimentological studies show varied depositional environments comprising natural dams formed by accumulations of plants promoting the development of upstream water bodies. The very negative δ13C values indicate that the Marseille tufa is not travertine sensu stricto but tufa deposited by local cold-water rivers. Palynological analyses indicate a semi-forested, diverse, mosaic vegetation landscape dominated by a Mediterranean pine and oak forest. Along the streams, the riparian forest was diverse and included Juglans, Castanea, Platanus and Vitis. The potential diet reconstructed from pollen was varied. The most surprising discovery was the presence of proto-cereals, which could potentially enrich the diet with carbohydrates. The identification of spores of coprophilous fungi seems to indicate the presence in situ of large herbivore herds. It is possible that, as in Anatolia, the disturbance of ecosystems by large herbivores was responsible for the genetic mutation of Poaceae and the appearance of proto-cereals. Climatic reconstructions indicate a slightly cooler and wetter climate than the present. [ABSTRACT FROM AUTHOR]

The integrative analysis of a lacustrine carbonate succession from Butte Iouton hill (Vistrenque basin, SE France) brings new insights into depositional models and stacking patterns of oolitic saline lake margins and provides new details regarding the late Eocene paleogeography of southeast France. Depositional facies analysis and paleoenvironmental reconstructions allow reconstructing an oolitic lacustrine ramp model, displaying from the proximal to the distal areas: (1) shallow marginal saline lake domain with deposition of planar microbial laminites, and molluscan-ostracodal wackestone, (2) a more distal and open lacustrine environments with low to moderate energy characterized by the deposition of peloidal grainstones and (3) a domain of higher energy with accumulation of ooids mixed with peloids in the vicinity of the area of ooid production. Lake margin carbonate sedimentation dominantly occurred during stages of lake transgression while subaerial exposure surfaces developed during periods of negative inflow-evaporation balance (forced regression). Carbon and oxygen isotopes together with vertical trends in salinity inferred from molluscan associations show that lake transgression does not result from increasingly positive freshwater-evaporation balance volume but from the combination of subsidence and outflow from neighbouring saline waterbodies. The Butte Iouton carbonate margin is part of a set of interconnected saline lakes, occupying continental basins from Languedoc and Rhodanian region during the Priabonian, with a siliciclastic-dominated sedimentation in the southern margin, sourced by erosion of Pyrenean reliefs, and a carbonate-dominated northern margin with significant oolitic sedimentation in high-energy nearshore area.

The seaward extension of onshore formations and structures were previously almost unknown in Provence. The interpretation of 2D high-resolution marine seismic profiles together with the integration of sea-bottom rock samples provides new insights into the stratigraphic, structural and paleogeographic framework of pre-Messinian Salinity Crisis (MSC) deposits of the Provence continental shelf. Seven post-Jurassic seismic units have been identified on seismic profiles, mapped throughout the offshore Provence area and correlated with the onshore series. The studied marine surface and sub-surface database provided new insights into the mid and late Cretaceous paleogeography and structural framework as well as into the syn- and post-rift deformation in Provence. Thick (up to 2000 m) Aptian-Albian series whose deposition is controlled by E-W-trending faults are evidenced offshore. The occurrence and location of the Upper Cretaceous South-Provence basin is confirmed by the thick (up to 1500 m) basinal series downlaping the Aptian-Albian unit. This basin was fed in terrigenous sediments by a southern massif (“Massif Méridional”) whose present-day relict is the Paleozoic basement and its sedimentary cover from the Sicié imbricate. In the bay of Marseille, thick syn-rift (Rupelian to Aquitanian) deposition occurred (>1000 m). During the rifting phase, syn-sedimentary deformations consist of dominant N040 to N060 sub-vertical faults with a normal component and N050 drag-synclines and anticlines. The syn-rift and early post-rift units (Rupelian to early Burdigalian) are deformed and form a set of E-W-trending en echelon folds that may result from sinistral strike-slip reactivation of N040 to N060 normal faults during a N-S compressive phase of early-to-mid Burdigalian age (18-20 Ma). Finally, minor fault reactivation and local folding affect post-rift deposits within a N160-trending corridor localized south of La Couronne, and could result from a later, post-Burdigalian and pre-Pliocene compressive phase.