Low-field magnetic susceptibility of the Bay of Seine seafloor dried grab samples at t0 (i.e. from June to September 2011), t1 (i.e. in March 2013), t2 (i.e. in June 2013) and t3 (i.e. in September 2013)

Low-field magnetic susceptibility of every sample was measured with an MFK1 susceptibilimeter (AGICO; K_LF ). The obtained value was normalized by the weight of the sample to determine the specific low-field magnetic susceptibility, X_LF.