Sedimentary processes and Quaternary stratigraphy of the Old Harry area, Gulf of St. Lawrence

NAÏS SIRDEYS; GUILLAUME ST-ONGE; JEAN-CARLOS MONTERO-SERRANO; NOELA SÁNCHEZ CARNERO; PIERRE-ARNAUD DESIAGE

Forêt Montmorency

Congreso; GEOTOP 2017; 2017

Fonds de Recherche du Québec - Nature et Technologies

The Old Harry (OH) offshore oil and gas prospect is a geological structure subject to numerous estimates of its volume, extractable quantities, and environmental hazards associated with its possible exploitation, butremains scarcely documented. In this context, we present here a multi-proxy record, including geophysics, sedimentological, mineralogical,geochemical, geochronological ( 210 Pb and 14 C) and paleomagnetic analyses (inclination, declination and relative paleointensity), in order to i) improve the geological characterization of this area since the last glaciation (2) reconstruct of post-glacial evolution of sedimentary environments and processe. Sediments are homogenous post-glacial muddy silts corresponding to units 1 and 2 described by Josenhans and Lehman (1999). 230 km 2 of multibeam coverage highlights the bathymetry where 3066 pockmarks were counted (~ 13 pockmarks/km 2 ). Their NW-SE alignment and orientation could be interpreted as bedrock topography deformations and/or due to the interaction between gas/fluid expulsion and currents.