Ice cores are recovered using a spectrum of ice core drills. The most portable and convenient drill is the hand-auger which has a depth range of 30 to 40 meters.
For deeper cores, a power source is necessary and the down-hole portion which actually extracts the core from the ice sheet or ice cap may be of several types. The electro-mechanical drill like that shown to the right which was used for the Antarctica - Plateau Remote site is very efficient for retrieving cores to about 200 meters depth on cold glaciers (temperatures well below freezing). Also electro-mechanical drills have been used by various countries (Australia, Denmark, France, Russia and the U.S.) to drill several kilometers through the major ice sheets of Antarctica and Greenland. For extracting cores in 'warmer' ice caps and glaciers (photo below) where temperatures may be only slightly below freezing, the conventional thermal electric drill may be the best tool.
Ice core drills may be powered by various sources, but the two most common are fuel-powered generators and solar panels.
Solar panels are a reliable, pollution-free and light-weight source of power. The use of solar powered drills for ice core recovery was pioneered by the Ice Core Paleoclimatology Group at OSU and Bruce Koci of the Polar Ice Coring Office in the early 1980s.
The superiority of solar power for ice core drilling (where adequate solar insolation is available) was first demonstrated by the recovery of two cores the bedrock on the Quelccaya Ice Cap in 1983. The ice cap margin is shown on the left. The solar powered drill system is shown to the right.
Since then, several ice cores have been obtained from glaciers at high elevation (>5,000 meters above sea level) using special, portable drills powered with solar panels. The photo to the left done shows the solar powered system used on Huascarán.
A new ethanol thermal electric drilling system has been developed for intermediate (1,000 meters) ice coring in cold glaciers. The system is light-weight (about 1,000 kg including a 6 kw diesel generator and a 6.6 meter diameter shelter), environmentally safe and capable of recovering a 100 mm diameter ice core at the rate of 400-500 meters per week. The system can be installed easily in 16 hours, and currently is ready for use in the Franz Josef Land area.
A cold storage building (shown in photo on the right) contains two 30' by 35' freezer compartments with rack-type storage units which are maintained at -30o to -40oC and can hold about 3,000 meters of frozen ice cores.
The freezer facility has three main compressors and a backup compressor and a gas-powered system consisting of a generator (shown in photo on the left).
Ice core processing such as the cutting and pre-preparation of samples for lab analyses as well as various analytical measurements on solid ice such as stratigraphy and structure studies (photos below), are conducted in the two cold labs (-10oC) attached to the deep(-30oF) storage unit.
The Ice Core Paleoclimatology Group is equipped with state-of-the-art instruments which perform multi-parameter analyses on melted ice samples. Stable isotopic ratios of oxygen and hydrogen are determined with a Finnigan-MAT mass spectrometer (shown in photo on the right) at a rate of 200 samples per week. Radioactivity of particulates filtered from meltwater samples is measured on a Tennelec Alpha/Beta counting system.
The rest of the analyses are performed in the large Class 100 Clean Room facility (shown above). Class 100 means there are less than 100 particles (diameter > 0.5 µm) per cubic foot of air. Inside the clean room, pre-cut ice samples are cleaned using highly purified deionized water from several Millipore water systems and prepared for dust and chemical studies. Microparticle concentrations in melted samples are determined in 16 size ranges using Model TAII Coulter Counters and in 256 size ranges using the Coulter Multisizer. Inorganic species in melted samples are measured using an atomic absorption spectrophotometer and
several ion chromatographs, one of which is equipped with an autosampler (shown below).
There are other facilities available on campus for specialized analyses such as scanning electron microscopy (SEM), microprobe, gas chromatography/mass spectrometry (GC/MS) and inductively coupled plasma mass spectrometry (ICP-MS).
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Last Updated: 08/29/96