NEOTECTONIC IN CONFLUENCE AUBE AND SEINE. HYPOTHESIS OR REALITY?

Néotectonique dans la confluence de l'Aube et de la Seine Hypothèse ou réalité ?

Pierre Benoit (1)

1 Laboratoire Aquanalyse

During the 1970s, some flexible and brittle deformations are described, mainly in the alluvial terraces of Aube, Marne and Seine. The exploitation since 2010, at the confluence of the Aube and the Seine, of a Weichselian terrace eut during Holocene, presents a large number of deformations, flexible and brittle. The possible or igins are multiple: meteorite shock, ejection of biogas, fusion of buried periglacial ice, gravitational slips in channels, earthquakes ... Several origins can also be juxtaposed. Two orthogonal trenches, 30 m long and 2 m high, provide data on the relationships between deformations, most often associating inverse faults; gravitational collapses and extension. Six other trenches of 15m long complete the observations. The last faulted lands are from the base of the Holocene. There are also inject ions of brecciated chalky domes sometimes affecting the base of the Holocene . Finally, the decrease of the deformations, both in intensity and number, moving away from our study area at the crossroads of two important geological Paris Basin (faults of Bray and Saint Martin) militate for a mainlyseismic origin. Two low intensity earthquakes have occurred in this area since 1966. Key words: Paris Basin, Weichselien, ssds, seismites.

Domaines: Géologie appliquée

Pierre Benoit. Néotectonique dans la confluence de l'Aube et de la Seine Hypothèse ou réalité ?. 2018. ⟨hal-01666067v2⟩