In Beacon Valley surfaces are older than in Victoria Valley and rocks which have been scoured by wind for thousands of years form ventifacts (see below).
Friday, December 26, 2008
Saturday, December 20, 2008
In addition to taking long cores we also use a small rock drill to take samples from the upper 15 to 20 cm of the groundice. The picture below shows Ron and David opening a pit at the shoulder of a polygon from which they retrieve a small ground ice core (see second picture below). The ground ice here occurs in two different forms: as ice cemented sand and pure ice (light part). Ice cemented sand has only small fraction of ice and consits mostly of sand while the pure ice contains only little or no sediment.
The last days we have strong katabatic winds which generate on the Antarctic Ice Sheet. They warm up due to increasing atmospheric pressure from the Ice Sheet (3000 m elevation) to the valley at 400 elevation; temperature increases can be 10 to 20 degrees. The lenticular cloud in the picture below indicats the winds.