The Role of Salt in the Subaqueous Construction of Continental Margins

Lorenz G. Straub Award Ceremony

2015 Award Recipient: Filip Schuurman, dissertation completed at the Universiteit Utrecht, The Netherlands

Keynote speaker: Gary Parker, Professor, Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign 

Every continent is surrounded by a bench-like feature known as the continental margin. It consists of three parts: the near-shore continental shelf, the continental slope which dips toward deep water, and the continental rise which connects the margin to the abyss. The continental shelf has been traditionally interpreted to be drowned coastal plain associated with sea level rise. We show, however, that continental shelves are also presently being actively constructed subaqueously by the action of hypopycnal flows, i.e. sediment-laden rivers flows that are too light to overcome the barrier of dissolved salt and sink to deep water. Our model results show that the combination of hypopycnal flows and wave action gives rise to the seaward-migrating clinoform characteristic of active continental margins. We compare our results with the freshwater Lake Baikal, which is old, deep and has no continuous shelves.