Deposition Patterns of Ice Rafted Debris

Sediment accumulates in ice streams as they scrape along the bedrock and lateral topography and eventually end up in icebergs. This sediment is then slowly deposited along the ocean floor as the iceberg melts. Despite the importance of this process being well understood, throughout much of the literature it is assumed the sediment within an iceberg's structure does not have a significant effect on its melting properties. However, through an experimental investigation we discovered the melting behavior of an iceberg depends heavily on its sediment distribution. In fact, the presence of sediment within an iceberg causes an accelerated melt rate, the formation of unique melt water-sediment plumes, and can lead to the iceberg splitting into multiple pieces. Accounting for this new melt behavior, we designed laboratory experiments to investigate the sediment deposition patterns formed by sediment laden icebergs. The novel results from these experiments differ with those predicted by preexisting theories on sediment deposition, shed new light on Heinreich events, and if included in ocean models they could improve their accuracy.