Southern Alaska margin: interactions of tectonics, climate, and sedimentation (Integrated Ocean Drilling Program Expedition 341)

Projections of future climate change under higher atmospheric carbon dioxide concentrations rely upon our understanding of the relationships and feedbacks that operate between different climate components, either as processes (ocean circulation, ice-sheet behaviour) or regions (e.g. low versus high latitudes). A number of key variables within the modern climate system have been linked to major climate transitions in the past, but whether they drove, amplified, or responded to climate events remains a topic of intense debate.

The focus of this research expedition is to drill a series of marine sediment cores in a transect close to South Alaska, in order to investigate the links between mountain building, ice sheet growth, and climate change. Recent research has shown that the uplift of mountains can affect local and regional climate by affecting the pathways and intensities of precipitation. It can also lead to ice sheet growth, and to increased erosion of the land surface. The increase delivery of sediments and freshwater from the mountains to the ocean can affect biological productivity and the patterns of ocean circulation in areas proximal to the mountains. In contrast, it has also been proposed that cooling and changes in ocean circulation at a regional scale (e.g. across the North Pacific Ocean) could be important for allowing or encouraging the growth of ice sheets, and regional warming might be important for driving ice-sheet retreat.

This complex set of interactions has been difficult to assess because there has rarely been an opportunity to recover long sequences of sediments which contain both climate signals and evidence for erosion and ice sheet growth/decay. In this expedition we will recover a series of cores which are progressively closer to shore, which span millions of years but which also preserve evidence for rapid climate events and the response of the environmental conditions onshore. The results will be important for a wide range of academic interests, spanning climate change, tectonics, biogeochemical cycling, glaciology and catchment dynamics.

The PI will actively participate in the centrally-organised outreach and educational events which are planned for the expedition through IODP. These are organised by the two shipboard education officers (Alison Mote, Carol Larson). Regular updates and blogs will be posted at the dedicated website for the expedition (via http://joidesresolution.org/), and ship-to-shore broadcasts will occur throughout the expedition (via http://joidesresolution.org/node/2742). The Department of Geography in Durham will also host links to the expedition webpages, and existing Outreach programmes at the University will be utilised to promote the expedition and its findings through the IODP resources. There are no direct cost implications associated with participation in these activities since they will be driven by pre-planned shipboard programmes.