How does the meridional overturning circulation affect sedimentation rates in the North Atlantic?
Downwelling speeds in the deep water formation areas are likely not significant when compared with the settling speeds of most sediment particles. While deep waters have clearly defined oxygen and nutrient characteristics, it does not seem likely that they can have a particular sedimentary character.

The deep water circulation associated with the meridional overturning circulation (MOC), while not very intense (a few cm/s), can transport some of the finer sediment classes along with it. 

The main sedimentary signal is likely associated with calcium carbonate. The shutdown of the MOC could have significant effects on the CaCO3 balance (Chikamoto et al., 2008).