Mesozoic halokinesis and basement inheritance in the eastern Provence fold-thrust belt, SE France

Abstract

The Provence Chain incorporated preexisting halokinetic and basement features which have played a key role in the structural evolution of the thrust systems. Field structural data, previously published geological maps and exploration well data have been used to interpret a new ~80 km-long balanced and restored cross section across the eastern Provence fold-thrust Diapiric structures were mainly eroded during and after the Pyrenean-Provence compression then reactivated during Oligocene extension and Miocene to present-day Alpine compression. Cross section balancing shows a total horizontal shortening of 28.5 km related to the Pyrenean-Provence and Alpine compressions. The eastern Provence fold-thrust belt integrates preexisting halokinetic folding which can be misinterpreted as resulting to compression. This suggests that a significant amount of folding in fold-thrust belts can results from an early halokinetic fold system developed during the pre-contractional passive margin evolution.

Evolution of a salt-rich transtensional rifted margin, eastern North Pyrenees, France

“…Although our area provides limited data on Jurassic stratal geometries, we propose that diapirs began to grow gently from the Early Jurassic onward. This hypothesis is consistent with recent studies in adjacent Pyrenean, Iberian and Alpine domains that document gentle Jurassic growth synclines developing between passive salt pillows with little evidence of initial reactive diapirism (Graham et al 2012;Espurt et al 2019;Labaume and Teixell 2020;Vergés et al 2020).…”

“…This three-step history of halokinetic activity is very similar to that established further west in the North Pyrenean Zone by Canérot et al (2005) and Labaume and Teixell (2020). In the Pyrenean-Provençal belt of SE France, Espurt et al (2019) document diapiric activity throughout the Jurassic and during the Albian and Late Cretaceous, with reactivation during the latest Cretaceous-Paleogene compression phase and then during backarc opening of the Gulf of Lion (Fig. 14).…”

“…This new knowledge is now stimulating a reassessment of the evolution of inverted salt-rich margins preserved in fold-and-thrust belts (e.g. Graham et al 2012;Espurt et al 2019;. The challenge is to recognize the imprint of the presence of salt and its influence in both rift and subsequent fold belt evolution.…”

Assessing post-pliocene deformation in a context of slow tectonic deformation: insights from paleoseismology, remote sensing and shallow geophysics in Provence, France

“…In Provence, it is proposed that the deformation of the sediment cover east of the MDFS results from deep-seated basement thrusts associated with cover décollements and salt tectonics (Tempier, 1987;Rangin et al, 2010;Espurt et al, 2012Espurt et al, , 2019Bestani et al, 2015Bestani et al, , 2016. local landslide phenomena on the borders of Quaternary hydrological re-incisions.…”

Jurassic Salt Tectonics in the SW Sub‐Alpine Fold‐and‐Thrust Belt

“…Salt tectonics has been known in this area since the 1930s (e.g., Goguel, 1939; Lapparent, 1940). At the scale of the SW Alps (Figure 1), salt structures have been recognized in the Vocontian domain, in Provence, in the sub‐Alpine fold‐and‐thrust belts, in the Alpes‐Maritimes, and in the Briançonnais (Figure 1) (Arnaud et al, 1977; Bestani et al, 2016; Casagrande et al, 1989; Dardeau et al, 1990; Dardeau & de Graciansky, 1990; de Graciansky et al, 1986; Delpech, 1988; Desmaison & Guilhaumou, 1988; Edon et al, 1994; Ehtechamzadeh Afchar & Gidon, 1974; Emre, 1977; Emre & Truc, 1978; Espurt et al, 2019; Gidon, 1997; Gigot et al, 2013; Goguel, 1939; Graham et al, 2012; Huyghe & Mascle, 1999; Kerckhove & Lereus, 1986, 1987; Lapparent, 1940; Mascle et al, 1986, 1988; Perthuisot & Guilhaumou, 1983). Even though authors tried to introduce salt activity as having played an important role in the structural inheritance of later compressional structures (Dardeau et al, 1990; Dardeau & de Graciansky, 1990; de Graciansky et al, 1986), its involvement in the structuration has mostly been underestimated and limited either to the role of décollement level for thrusts, or to the formation of local complexities such as the Laus diapir next to Remollon (Figure 3) which was considered to be the result of an extensional event on the Digne Nappe during the Oligocene (Emre, 1977).…”