This record reflects slow buildup of global glaciers and gradually colder air temperature followed by sudden collapse of ice sheets, return of glacier melt water to the sea, and warming of the atmosphere. Map of the Greenland Ice Sheet showing the Summit. GRIP and GISP2 ice cores have been drilled there, an area of thickest ice with minimal ice movement. The GISP2 drilling dome on the ice surface. The dome is connected to nearby surface and buried workshops and living quarters.
Technician cleans the cutting head of the drill.
Just above the cutting head, a drill barrel will hold the ice core. The equipment shown here is for cores 10 cm in diameter, the standard for most ice drilling. At GISP2, 13.2 cm cores were drilled. Photomicrograph in cross-polarized light of ice sample from 333 m depth in the GISP2 core. Mid-sized crystals show homogeneous ice that has not been sheared by ice flow.