Previous   |   Next

doi:10.2204/iodp.proc.323.111.2011

Introduction

The paucity of data in critical regions of the Pacific such as the Bering and Okhotsk Seas has prevented an evaluation of the role of North Pacific processes in global climate change. The Bering and Okhotsk Seas are marginal North Pacific basins that store in their thick sedimentary sequences a record of major past climate changes. Because Pacific intermediate water is formed in these basins, they are not just recorders of but are potentially critically involved in causing major climate changes. Thus, drilling in these two marginal backarc seas will answer questions not just about the global extent of climate trends and oscillations but also about the mechanisms that produce them.

Integrated Ocean Drilling Program (IODP) Proposal 477 proposed to drill sediment appropriate for a detailed study of the Pliocene–Pleistocene evolution of millennial- to orbital-scale climatic oscillations recorded in the Bering and Okhotsk Seas. Biological, chemical, and physical oceanography as well as adjacent continental climate are highly sensitive to global climate conditions and are recorded by variations in the sedimentary composition of diatoms and other microfossil groups, as well as many other paleoclimatic indicators. Intermediate water formation in these regions can be tracked using paleoceanographic proxies of subsurface water that can be related to open Pacific records. Sediments can be used not only to extract records of climate and intermediate water ventilation in these high-latitude marginal seas but they can also be applied to interrogate the effect of oceanographic changes imposed at the Bering Strait Gateway (through the Arctic) on heat and nutrient partitioning between the Atlantic and Pacific Oceans. The proposed drilling would, for the first time, provide continuous and high-resolution paleoenvironmental records from these subboreal seas. These new records would reveal and test our understanding of the processes that influence intermediate water ventilation and its role in global climate change over the past 5 m.y.

IODP Proposal 477 was first submitted in June 1995 to the Ocean Drilling Program (ODP). The proposal was transferred to IODP and subsequently approved for drilling by the IODP–Science Advisory Structure–Science Steering and Evaluation Panel (IODP-SAS-SSEP) in May 2004. The IODP-SAS-Science Planning Committee (SPC) recommended the proposal for ranking in June 2004 and forwarded it to Operations Committee/Operations Task Force (OPCOM/OTF). The proposal was initially reviewed by the Environmental Protection and Safety Panel (EPSP) on June 2005 (in Edinburgh, Scotland) and approved in December 2005 (in Hawaii, USA). Taking into account discussions with IODP-SAS-Site Survey Panel (SSP) and EPSP, all the available site survey data sets were processed. These included original site survey data (navigation, subbottom profile, and seismic reflection) of Cruise KH99-03 (R/V Hakuhou-maru) responding to the request by the EPSP (in 2005 and 2006) to provide them using consistent procedures for proposed sites in the Bering Sea. We updated corrected data sets of navigation, swath bathymetry map by narrow-beam bathymetric operations, 3.5 kHz subbottom profiles, and reprocessed multichannel seismic (MCS) reflection profiles of site-specific cross-line surveys. All advance-processed data sets were uploaded to the IODP Site Survey Database (SSDB).

This document contains information about all processed data sets submitted in support of proposed drilling sites in the Bering Sea, some of which were drilled during IODP Expedition 323 (Table T1; Fig. F1).

Top of page   |   Previous   |   Next