Dust in ice cores
Antarctic ice cores are an archive of the climate – and of the dust that has been blown from various sources to Antarctica throughout thousands of years. Now this dust provides valuable information both on the wind in the past as well as on the dust sources.
There are several ways to measure what kind of insoluble dust particles are enclosed in the ice core, and how much dust has accumulated.
One of them uses a laser beam which is passed by a meltwater flow. Particles in the meltwater flow cause a shadowing, which is detected by a detector mounted on the opposite site. Another technique detects changes in impedance caused by particles, when the sample is pumped through a small orifice. These two techniques give beside the dust concentration also the dust size distribution.
An easy way to determine the soluble mineral dust content in ice cores is to measure the non.sea-salt Calcium concentration (nss-Ca), by standard ion chromatography. More advanced measurements of the dust concentration and the chemichal composition can be performed by using inductively coupled plasma mass spectrmetry (ICP-MS).
Research shows that the dust concentration in ice cores is up to 2 orders of magnitude higher during glacial stages than during interglacials. This is thought to be due to higher aridity and storminess during colder climate. By comparing the chemical composition of the ice core dust with samples from the potential source areas, southern South America could be determined as the source for dust on the East Antarctic plateau during Glacial times.
