The First Deep Coring in the Central Arctic Ocean: The Drilling of the Lomonosov Ridge by the IODP
David McInroy and Robert Gatliff
ECORD Science Operator, British Geological Survey, Edinburgh, United Kingdom.
The ocean geoscience research community has long wished to core deep holes in the Arctic Ocean seabed to start unravelling the geology, resources and environmental changes of the least understood ocean basin in the world.
The Integrated Ocean Drilling Program (IODP) is the most recent version of the ocean research drilling programme which follows the DSDP and the ODP. Under IODP, there is for the first time the option to charter vessels other than the JOIDES Resolution, which opened up the possibility to core in the central Arctic Ocean. In August-September 2004, the Arctic Coring Expedition (ACEX) became both the first IODP mission specific platform Expedition, and the first IODP Expedition to the central Arctic Ocean.
The greatest challenge faced by ACEX was the requirement that the drillship hold position in continuously moving sea-ice while coring. This required the support of two icebreakers, the Oden and the Sovetskiy Soyuz, to break up the sea-ice sheets as far as possible to protect a third ice breaker, the ice-strengthened Vidar Viking, specially converted to undertake the drilling and downhole logging program.
The ice conditions heavily influenced the operation, both en route and at the selected drill sites. Tremendous efforts were devoted to understanding, predicting and possibly controlling the ice conditions near the proposed drill sites. A detailed ice management plan, prepared by the Swedish Polar Research Secretariat (SPRS) and an international panel of experts, was implemented to allow the Vidar Viking to remain on station for up to 10 days at a time whilst the ice was broken up to pass around the drillship. The success of the Expedition is largely attributed to the high quality of the ice management expertise.
The small drillship and the support icebreakers had none of the usual laboratory facilities associated with IODP Expeditions; hence the initial analysis of the cores was undertaken by the Scientific Party at the IODP Bremen Core Repository in Germany. ACEX recovered cores from up to 428 m below the sea floor in waters around 1300 m deep, and thus achieved the first deep coring in the central Arctic Ocean. The results of the Expedition have been spectacular, and have been published in several high impact journals.
The total cost of the Expedition was around US$11M. The budget allowed for an Expedition duration of 38 days, and smooth transits in both directions between Tromsø, Norway, and the sites resulted in 24 days of operations.
In the new phase of IODP (2014-2023), it is hoped that several more Arctic coring expeditions will be undertaken.
AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.����������������������������������������������������