The mechanisms of overlapping of the Bresse graben by the Jura formations in the Vignoble area (France)

Abstract This paper aims to underline how powerful and important the balanced cross-section constructions are for understanding structural mechanisms, especially when several interpretations are possible. In the Vignoble area, between Lons le Saulnier and Arbois — French foothills of Jura, the frontal overlapping is proved by several drillholes. The classical interpretation is a thrusting through listric reverse faults and continuation of the decollement level underlying the Jura at the cover—basement interface. The balanced cross-section construction demonstrates that this assumption is not valid due to the necessary thinning and stretching of the overlapping formations in this region. This paper proposes a new solution where the overlapping, through listric normal faults, is like a huge gravity landslide, without any relation to the shortening and decollement of the internal Jura. The new interpretation is supported by the very consistent balanced crosssection of the displaced cover and by the extension structures observed in the field.