Modeling a 200-yr interruption of the Holocene Sapropel S-1

An oceanic general circulation model, previously used to simulate the conditions associated with the Holocene Sapropel S-1, is used to simulate the effects of a climate deterioration (represented as a cooling event) on the sapropelic circulation mode, The enhanced cooling (2 degrees-3 degrees C) induces deep convection in the Adriatic and the Gulf of Lions and intermediate water formation in the Aegean, where in all cases there had previously been only stagnant unventilated waters. The depths of ventilation (to similar to 1250 m) are in agreement with core data from this period, The short decadal timescales involved in modifying the sapropelic circulation suggest that such a climatic deterioration may be associated with the interruption of S-1 between 7100 and 6900 C-14 yr B.P., which divided the sapropel into two subunits. (C) 2000 University of Washington.