Résumés des présentations > By speaker > Baltzer Agnès

Haploops have been studied in the Bay of Concarneau from 1964 to the end of 1990 by Glemarec et Graal, (2003). Their expansion to the north has been observed along ten years but not to the north west due to the presence of Amphiura filiformi who destabilizes the sedimentary cover (Glémarec et al., 1987). The pockmarks field in the Bay of Concarneau has been reported by Ehrhold et al., (2006) in the frame of the REBENT program and eventually, the superimposition of the the pockmarks field and the Haploops settlement by Souron et al., 2009 and confirmed by Baltzer et al., 2014. Thus, it almost took 25 years to observe this spatial link. This overlapping has been observed in the Vilaine Bay, on the “Research Plateau” and since 2016 in the Loire estuary (Champilou et al., 2019). In each case, there are no Haploops outside the pockmarks fields and the densities of pockmarks and Haploops tubes are particularly high. The pockmarks are active ones and are superimposed, in the 3 areas to faulted eocene calcareous outcrops. New results from geochemistry and microbiology should help us to understand the links between pockmarks and Haploops. In another way, Haploops settlement may indicate active pockmarks and their extension should follow the gas/fluid expulsion pathways. An integrate study of this specific relationship in different areas along the world, may helps us to better constrain the time-scale duration of these shallow pockmarks fields activity.