Age of the Fontainebleau sandstones: a tectonic point of view

Yves Missenard,Oriane Parizot,Jocelyn Barbarand

doi:10.1051/bsgf/2017194

Abstract

The age of the cementation of the Fontainebleau sandstones, located in the upper part of the Rupelian Fontainebleau Sand Formation and largely outcropping in the south of the center of the Paris Basin, remains a matter of debate: did the silicification occurred at early times during Miocene, following sedimentation, or did it occurred during Quaternary cold climate episodes? In this work, we determined an orthogonal fracture network (main directions N115° ±5° and N025° ±5°) over an area of ∼6000 km2. The fractures are oblique to the adjacent valley orientation and to the quarry working face orientation, discarding a gravitational origin. This tectonic fracturing is superimposed on regional scale antiforms and synforms that may be at least partly controlled by inherited basement faults reactivation during Alpine episodes. The whole Fontainebleau Sand Formation seems to be folded, including the Fontainebleau sandstones. We establish a relative chronology of the various phenomena and propose that silicification at the origin of the Fontainebleau quartzite occurred during early or middle Miocene. Alpine stresses then induced Fontainebleau sand and quartzite folding and fracturing during late Miocene and Pliocene. Finally, the fracture network facilitated fluid circulations and secondary carbonate sandstones or quartzite precipitation probably during Quaternary cold climate episodes.

Highlights

Widely used for petrophysical, geophysical and sedimentological studies (e.g., Bosch et al, 2016; French and Worden, 2013; Haddad et al, 2006; Nasseri et al, 2014), for the pavement of Paris roads during the 19th century, or even as well-known climbing walls of the Fontainebleau massif, the origin, i.e., the age of silicification of the Fontainebleau sandstones remains a strong matter of debate.These hard consolidated sandstones, sometimes corresponding to quartzites, are mostly located in the upper part of a sandy unit, the Rupelian Fontainebleau Sand Formation, and widely crop out south of the Seine River southward from the centre of the Paris Basin (Fig. 1).They were first described in the mid-18th century by Buffon (1749)
The age of the cementation of the Fontainebleau sandstones, located in the upper part of the Rupelian Fontainebleau Sand Formation and largely outcropping in the south of the center of the Paris Basin, remains a matter of debate: did the silicification occurred at early times during Miocene, following sedimentation, or did it occurred during Quaternary cold climate episodes? In this work, we determined an orthogonal fracture network over an area of ∼6000 km2
We establish a relative chronology of the various phenomena and propose that silicification at the origin of the Fontainebleau quartzite occurred during early or middle Miocene

Summary

Introduction

Widely used for petrophysical, geophysical and sedimentological studies (e.g., Bosch et al, 2016; French and Worden, 2013; Haddad et al, 2006; Nasseri et al, 2014), for the pavement of Paris roads during the 19th century, or even as well-known climbing walls of the Fontainebleau massif, the origin, i.e., the age of silicification of the Fontainebleau sandstones remains a strong matter of debate.These hard consolidated sandstones, sometimes corresponding to quartzites, are mostly located in the upper part of a sandy unit, the Rupelian Fontainebleau Sand Formation (lower Oligocene), and widely crop out south of the Seine River southward from the centre of the Paris Basin (Fig. 1).They were first described in the mid-18th century by Buffon (1749). Widely used for petrophysical, geophysical and sedimentological studies (e.g., Bosch et al, 2016; French and Worden, 2013; Haddad et al, 2006; Nasseri et al, 2014), for the pavement of Paris roads during the 19th century, or even as well-known climbing walls of the Fontainebleau massif, the origin, i.e., the age of silicification of the Fontainebleau sandstones remains a strong matter of debate These hard consolidated sandstones, sometimes corresponding to quartzites, are mostly located in the upper part of a sandy unit, the Rupelian Fontainebleau Sand Formation (lower Oligocene), and widely crop out south of the Seine River southward from the centre of the Paris Basin (Fig. 1).

Results

Discussion

Conclusion