Preamble - IODP Workshop

Scientific drilling in the Chukchi Sea: Linking North Pacific and Arctic Ocean history

Introduction and overall objectives

The lack of deep-sea drilling is a huge impediment to our comprehension of the Arctic Ocean, one of the last remaining Earth Science frontiers and a stage for the most dramatic expression of climate change. Because of operational constraints in ice-covered waters, the only drilling in the Arctic Ocean thus far has been the 2006 IODP Leg 302, also known as the ACEX (Arctic Coring Expedition). The fast, climate-forced retreat of Arctic sea ice, which has dramatically accelerated in recent years, opens new prospects for drilling in the Arctic without the high-cost, multi-ship setup used in heavy ice conditions during the ACEX. The two areas of the Arctic, where seasonally ice-free water opens especially quickly are the Barents and Chukchi regions, which are affected by the warming influence of the Atlantic and Pacific oceans, respectively. These regions are therefore especially sensitive to climatic and paleoceanographic changes and constitute priority target areas for scientific drilling.

The Chukchi margin is one of the most sensitive high-latitude areas to both climate variability and sea-level fluctuations. It is in the Chukchi Sea and adjacent areas of the Arctic Ocean that vast expanses of open water now replace summer sea ice at accelerating rates. In addition to global climatic forcings, this dramatic change is related to the effect of Pacific water inflow via the Bering Strait, which influences sedimentary, hydrographic, biological, and ice conditions in and beyond this region. Late Cenozoic climatic, sea-level, and tectonic changes radically impacted the Chukchi shelf, a gateway between the Pacific and Arctic oceans that turns into a Beringian land bridge between America and Eurasia during low sea-level stands.

The significance of the Chukchi margin for studies of the Arctic-Pacific connection, sea-ice and glacial history, and high-latitude shelf-basin interactions makes it a natural attraction for research initiatives ranging from modern processes to geological history and prehistoric archeology. A number of research programs have targeted the Chukchi Sea and adjacent areas in recent years including expeditions with geological/geophysical components, and more are being planned for the coming years. These activities reveal a growing international interest in the Chukchi region, with a widening range of participating countries in addition to those that have traditionally worked in the Arctic in the 20th century. This reality creates incentives for broadening international cooperation, which can greatly increase the overall efficiency of the scientific output. An excellent international research opportunity can be provided by bringing the Integrated Ocean Drilling Program into the western Arctic.

Existing IODP proposals

The previous IODP drilling operation in the Arctic Ocean (ACEX) required a very costly and complex setup involving two icebreakers (one nuclear-powered) and a drilling platform. Ongoing sea-ice retreat makes the Chukchi region much easier to access without the use of ships with high icebreaking capabilities. For example, >5000 km of Multi-Channel Seismic Reflection data were collected at the northern margin of the Chukchi Sea in 2011 using a vessel not reinforced for sea ice.

Four drilling proposals have been developed thus far for the Chukchi Sea and the adjacent Beaufort margin, and another one is being considered for the Chukchi Borderland. Further development of these projects and related new proposals requires intellectual and organizational interaction between research groups involved.

One IODP project is planned for the southern-most Chukchi Sea and adjacent Bering Sea (IODP No. 680, The Bering Strait, Global Climate Change, and Land Bridge Paleoecology, PI’s S. Fowell and D. Scholl). Drilling of Cenozoic sedimentary basins on both sides of the Bering Strait will provide data on the history of the Arctic-Pacific gateway and Beringian land bridge. A broader range of Arctic-related issues will be addressed by drilling proposed further north (IODP No. 750, Chukchi Shelf to Slope Transect: Linking Beringian and Arctic Ocean history, PI’s L. Polyak and J. Brigham-Grette). The main target of this project is drilling extensive sediment accumulations at the mouths of large Herald and Barrow canyons, which carry most of the Pacific water and sediment load across the Chukchi shelf. This drilling is expected to shed light on the major questions of the Plio-Pleistocene paleoceanography and sedimentary evolution in the Chukchi region. Another project with similar objectives and research strategy will target the Beaufort margin off the Mackenzie River (IODP No. 753, Late Quaternary Paleoceanography and Glacial Dynamics in the Beaufort Sea, PI’s M. O’Regan et al). A more specialized proposal focuses on the investigation of gas-hydrates and permafrost on the Alaskan Beaufort margin (Alaskan Beaufort Margin: Investigating the Impact of Warming Since the last Glacial maximum on Climate-Sensitive Sediments in the Arctic, PI’s C. Ruppel et al). Questions related to tectonic evolution and deep-time stratigraphy of the Pacific sector of the Arctic are likely to be addressed by potential drilling at the Chukchi Borderland (prospective PI B. Coakley).

Developing strategy for drilling

This workshop will bring together members of various research groups involved in the existing drilling proposals as well as surveying and investigation of the Chukchi and Beaufort seas and adjacent areas of the Arctic Ocean. The exchange of information and ideas between these groups is critical for outlining the major directions of further research, especially in relation to scientific drilling.

To facilitate drilling development, the workshop will explore the possibilities of linking the existing proposals within the IODP structure and will discuss sites that could be drilled with the Joides Resolution. This will entail discussing a range of issues including:

  • Scientific themes/questions
  • Key sites
  • Site survey data needed
  • Approach/proxies
  • Research coordination and data exchange

This is our opportunity to develop a coordinated approach for scientific drilling in the western Arctic. Bring your results and ideas – let’s make it happen!