 Beryllium-10 (10Be) is also formed from nitrogen and oxygen, and deposited in polar ice.However, 10Be deposition can be strongly related to local weather and shows extreme geographic variability; it is also more difficult to assign dates.Nevertheless, a 10Be increase during the 770s was found in an ice core from the Antarctic, though the signal was less striking because of the lower time resolution (several years); another smaller increase was seen in Greenland.