Million year ice core
Australia is gearing up to lead an international project to drill an ice core in Antarctica containing a one million year record of the Earth’s climate.
Antarctic ice cores contain chemical constituents such as carbon dioxide, sulphur, sea-salt and dust, which provide crucial information on past climate and climate processes. This information is key to understanding current climate and predicting future change.
A one million year record is significant because it spans a time in Earth’s history when ice age cycles shifted their pacing from 41 000 years duration to 100 000 years duration. While we don’t know what caused this shift, an ice core covering this period would allow scientists to extract a direct record of carbon dioxide and see what role, if any, it may have played.
Australia’s contribution to international geophysical surveys across the region has helped narrow the location of ice that is likely to contain a one million year climate record – with a leading prospect near Dome C. This location needs to have thick ice with fine annual layers and be free from melting at the base from geothermal heat.
Australian Antarctic Division Deep Ice Coring Systems Lead Project Officer, Mr Al Elcheikh, said it was likely Australia and a European team would lead two drill operations near this location.
“We’re working with our European collaborators to model the best locations for drill sites and to build the drills required,” he said.
The first traverse in support of the Australian component of the project is expected to occur in the 2019–20 season, with delivery of much of the mobile station and drill camp infrastructure and equipment (see main story). This will include an ice core drilling shelter, core storage and drill workshop facilities, and accommodation for up to 16 people, about half of which will be ice core drilling personnel.
In 2020–21, science personnel will set up the drill and associated infrastructure in preparation for the start of a three to four year drilling program the following year.
“We anticipate there will be seven or eight people working two 8–9 hour shifts on the drill,” Mr Elcheikh said.
“We aim to drill about 150 metres per week, so over a field season of 6–8 weeks, depending on logistical factors, we hope to drill between 900 and 1200 metres of ice core in each full season. This will produce between 6.5 and 8.5 tonnes of ice core a year, which we’ll transport to the ship using the traverse.”
Australian Antarctic Division