Recent melting status at the upstream part of the Gangjoe La Glacier, Bhutan Himalayas, determined by pollen analysis of an ice core

Pollen analyses were carried out on samples from a snow pit and an ice core in the saddle of the Gangjoe La Glacier in the Bhutan Himalayas in 2002. The main purpose of this study was to implement an ice core analysis to investigate the recent snow depositional environment at the upstream part, particularly to understand melting status. The total sample length was 6.60 m. Three pollen concentration peaks were observed at the ice core depths of 0.46-0.56, 1.44-1.54, and 2.52-2.56 m. These peaks contained pollen, from various taxa, that had scattered in the study region between March and October. On the other hand, air temperature data showed that the summer melting season on the glacier was from June to September. Therefore, we assumed that snow deposited from approximately March to September over the past three years was lost due to summer melting. The ice layers between the pollen concentration peaks seemed to correspond to snow accumulation from September to March of the following year. These results provided a clue to better understand melting and snow depositional conditions at the study site.