Ice core drilling on Southern Patagonia Icefield -Development of a new portable drill and the field expedition in 1999-

A 45.97m-deep drilling operation was carried out during November/December 1999 on the accumulation area of Tyndall glacier (50°59′05″S, 73°31′12″W, 1756m a. s. l.) at the southern end of the Southern Patagonia Icefield. A portable electromechanical drilling system was developed for ice-coring on temperate glaciers which often have aquifers near the pore-close off depths. The firn-core obtained was subjected to visual stratigraphic observations and bulk-density measurements. Preliminary results suggest an extremely high accumulation rate (about 12-14m a^<-1> w. e.) at the drilling site. The drilling operation was strenuous because of the continuous strong wind and enormous snowfall which forced the members to survive for nearly three weeks in a snow cave before evacuation.