The technology needs for the Arctic are outside the capabilities
of the long-termed leased platforms in IODP with the exception
of high latitude gateway drilling, where these platforms could
compliment in areas at about 65° to 78° N. For the Antarctic
fit to mission platforms are needed for scientific drilling in
areas with permanent sea-ice cover and drilling in diamict. Mission
Specific Platforms in the Antarctic will complement JR-type drilling
in more distal parts of the margin.
Three preconditions are required for drilling in both polar areas:
an ice class vessel, a dynamic positioning system and a moon pool.
Beyond that the Arctic and the Antarctic investigation need following
different tools and strategies:
- Improvement of Antarctic core recovery at glaciated shelves
and adjacent slopes
- Arctic multi-ship operations
- An icebreaker with deep drilling capability
- Data collection for target identification and site surveys
Improvement of Antarctic core recovery at glaciated shelves
and adjacent slopes
The circum-Antarctic continental margin has been drilled by ODP,
but scientific results have been hampered by inadequate sediment
recovery in diamict on the continental shelf and slope. The ODP
rotary drilling in diamicton and coarser fraction lithology in
the continental margin setting of circum-Antarctic resulted in
minimal recovery in unconsolidated sediments and less than 30%
recovery in consolidated sediments. Mission Specific Platforms
are needed for Antarctic operations to provide both hydraulic
piston coring and diamond coring with mud circulation in conjunction
with a sensitive active heave compensation system to yield a highest
degree of core recovery.
Arctic multi-ship operations In contrast
to the Antarctic the Arctic is at a vastly different stage of
examination. Here, the permanent pack-ice cover of the polar basin
has prevented almost any kind of investigation. Paleo-environmental
and other studies are very few. For drilling operations in the
central Arctic an ice-class platform is necessary and this has
to be guided by at least two icebreakers to permit ice management
under heavy pack-ice conditions and guarantee stable positioning
during drilling operations. In preparation of the
IODP
proposal 533 (Drilling Lomonosov Ridge) an IODP working group
had approved the logistical and operational feasibility of a multi-ship
operation in the central Arctic. The leg was drilled in autumn 2004
(ACEX -
Arctic Coring Expedition).
An icebreaker with deep drilling capability
A long-term drilling program of 10 to 20 years is necessary to
achieve the open scientific questions concerning Arctic climate
and tectonic evolution. To fulfil this long-term prospectus of
Arctic drilling the European Polar Board of the European Science
Foundation is proposing the construction of a research icebreaker
with a deep drilling capability dedicated to polar research. Delegates
of several European countries have developed a science plan for
Arctic research. The new icebreaker - AURORA
BOREALIS - would be conceived as an optimized science platform
and will allow conducting long, international and interdisciplinary
expeditions into the central Arctic Ocean during all seasons of
the year. Removable drilling equipment should fulfil the needs
of IODP Arctic drilling proposals. It should be equipped with
a modularized mobile laboratory system and two moon pools for
drilling and deployment of Remotely Operated Vehicles (ROV) and
Autonomous Underwater Vehicles (AUV). Preliminary planning envisages
the launching of the new icebreaker in 2006.
Data collection for target identification
and site surveys The necessary data base for definition of
optimum drill sites in ice-covered water is with very few exceptions
limited or non-existent, particularly in the Arctic Ocean. A broad
multi-national effort with dedicated cruises is needed to collect
regional seismic data for identification of target regions. These
areas must in turn be subject to follow-up surveys in order to
satisfy the site requirements for drillable locations.
Scientific
Focus
