EUROCOLD LAB - TALDICE

TALDICE

The TALos Dome Ice CorE (TALDICE) is a European ice core research project (Italy, France, Germany, Switzerland, United Kingdom) aimed at retrieving an ice core reaching back through the previous two interglacials (about 250,000 years), from a peripheral dome of East Antarctica. Logistical support was provided by the Italian Antarctic Programme (Programma Nazionale di Ricerche in Antartide). TALDICE ice core analysis will contribute to decipher climate change mechanisms and will help to explain past, present and future climate trends. The results obtained at Talos Dome will complement, verify, and augment the palaeorecords collected at the "near-coastal sites" EPICA-DML, Berkner Island, Taylor Dome, Siple Domeand Law Dome DSS etc., and at other Antarctic deep drilling sites (EPICA-Dome C, Vostok, Dome Fuji). As such, it would be a significant contribution to the International Partnerships in Ice Core Sciences 40,000 years network: a bipolar record of climate forcing and response.

The main science objectives of the TALDICE project

Determine temporal/spatial patterns in environmental parameters that relate to the ocean surface conditions (e.g., sea ice, marine biological productivity, storm activity) in the Southern Ocean/Ross Sea region;
Reconstruct the sequence of events (including forcings and responses) through the last two glacial-interglacial transitions across Antarctica at high resolution;
Synchronise the TALDICE records using high-resolution measurements of CH4, CO2, volcanic and dust stratigraphies, and isotopic compositions of air components, as well as absolute dating of volcanic layers;
Identify climate modes and teleconnection patterns under different climate boundary conditions (orbital forcing, greenhouse gas concentration, land ice masses);
Compile high-sensitivity evidence of subdued rapid climate/environmental transitions throughout the Holocene;
Reconstruct snow accumulation changes at inland and coastal sites and identify changes in ice volume and local ice sheet altitude, from the Last Glacial Maximum through the Holocene to the present.

Drilling an ice core

Drilling was performed with electro-mechanical drilling equipment, using a drilling fluid to balance the overburden of pressure and to prevent ice flow closure of the borehole. During the 2004-2005 season, a 4 m deep trench was dug using vehicle (PB330), and an initial pilot hole and reaming were drilled using the James Ross drilling system available at LGGE (drilling capacity of 400 m) to a depth of approx 128 m. The first 96 m was lined with a fibre reinforced plastic casing to prevent the borehole from collapsing in on itself and to prevent the drilling fluids from seeping out of the bore hole. At the end of drilling operations, 10 metres of casing (including up to 5 m above the surface) were added to the original casing to allow access to the hole later on. The hole can thus be used for decade for temperature or ice dynamics studies. During the 2005-06, 2006-07 and 2007-08 austral summer seasons, the initial pilot hole was filled with drilling fluid, and drilling continued down to 1620 m using a Berkner drill system provided by LGGE and BAS. An Italian IDRA drill system was tested during the 2007-08 season, but only over a few runs. This drill tries to combine the "Russian pumping system" and the more classical lower part of the EPICA drill. The chip compaction in the chip chamber did not work properly, which did not allow the drill to produce a long enough core.

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