The Roussillon Basin (S. France): A case-study to distinguish local and regional events between 6 and 3 Ma

Abstract

The Roussillon Basin is a non-silled Miocene sedimentary basin filling a late Oligocene-early Miocene graben. The basin was intensively impacted by the 2 Messinian fluvial erosion, as evidenced in exposed sections, in seismic profiles and in deep boreholes drilled for hydrocarbon exploration. As the basin was open to the Mediterranean Sea, the huge drop in sea level at the peak of the Messinian Salinity Crisis is clearly recorded, along with the subsequent sudden marine reflooding and the resulting prograding sedimentary filling, particularly in Gilbert-type fan deltas. Here, the Messinian Erosional Surface (MES) is accurately mapped in a high-resolution document, which corrects the confusion resulting from the set of 1:50,000 scale regional maps. Aim of the 3D reconstruction of the MES is to modernize geological mapping, a crucial challenge for Mediterranean and peripheral areas. Thanks to a reliable chronostratigraphy provided by planktonic foraminifers, calcareous nannofossils, micro-and macro-mammal remains, paleomagnetism and a 10 Be cosmogenic nuclide-derived study, our reconstruction is one of the most comprehensive models of changes in sea level from 6 to 3 Ma. After the marine reflooding of the Mediterranean Basin at 5.46 Ma, the fluctuations in sea level recorded in the Roussillon Basin were forced by global changes. Following reflooding, the Prades large olistostrome collapsed prepared by the previous exhumation along the Canigou fault. The olistostrome is a good example of a local accident resulting from Messinian events. The exceptional changes in sea level at the peak of the Messinian Salinity Crisis deeply marked the Roussillon Basin, momentarily overprinting the Pyrenean orogenesis.

Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

“…The Late Miocene reactivation of the Têt Fault as a right-lateral strike-slip fault 40 was contemporaneous with the deposition of 400-800 m of non-marine sediments in the Cerdanya Basin 41 . In the Roussillon Basin, a maximum of 800-900 m of post-Messinian sediments is preserved 42 . The formation of the Cerdanya Basin was synchronous with normal faulting along the oblique NNW-trending Transverse Fault system in the Sierras Transversales 43 , volcanism in Emporda (10-9 Ma) and Selva (7-2 Ma) region, North-East Catalonia.…”

High‐resolution evolution of terrigenous sediment yields in the Provence Basin during the last 6 Ma: relation with climate and tectonics

“…The erosion created two main incised valleys onshore: (1) to the East, the first one corresponds to the Rhône system together with a network from the region of Montpellier, both joining downstream into a single valley (Clauzon, ). (2) The other to the West corresponds to the Orb‐Hérault system with headwards extending from the Languedoc and Roussillon region (Clauzon et al ., ). A smaller incised valley to the South‐West corresponds to the Têt‐Tech system.…”

“…Assuming a downstream limit of these incisions that corresponds to the present‐day coast‐line and a mean denudation thickness up to 50 m (estimated from the Pliocene abandonment surface), the isobath map of the MES onland allows calculating the onshore volume incised by these two main valleys. They are respectively estimated to 1500 km 3 and 400 km 3 (Clauzon et al ., ). The recycled shelf material has been estimated to ~3000 km 3 in the Languedoc and Roussillon areas (Mauffret et al ., ; Lofi et al ., ) and extrapolated to ~10 000 km 3 in the whole Rhône Valley and on the entire shelf of the Gulf of Lions where the MES has been observed (>20 000 km 2 ) (Bache et al ., ).…”

Tracking geothermal anomalies along a crustal fault using (U-Th)/He apatite thermochronology and REE analyses, the example of the Têt fault (Pyrenees, France)

“…Later, ) two minor tectonic events were recorded on these faults: a Miocene dextral strike-slip phase along the Têt fault leads to the formation of pull-apart basins (Fig. 1B) such as Cerdagne and Roussillon basins (Cabrera et al, 1988;Gibert et al, 2007) and a second extensional tectonic event during the Plio-Quaternary (Carozza and Baize, 2004;Lacan and Ortuno, 2012;Petit and Mouthereau, 2012;Clauzon et al, 2015). https://doi.org/10.5194/se-2020-54 Preprint.…”

“…massifs is estimated at about 2000 m from a large consensus but last period of relief edification and Têt fault activity is still debated. The last vertical movements are related either to the Miocene tectonic phase with a maximum of m of footwall uplift (Cabrera et al, 1988;Mauffret et al, 2001) or to the Plio-Quaternary tectonic phase with up to 500 m of exhumation (Carozza and Baize, 2004;Lacan and Ortuno, 2012;Clauzon et al, 2015). It must be stressed that some authors consider that any vertical displacement occurred during the Plio-Quaternary (Petit and Mouthereau, 2012).…”