Permafrost environment during the last glacial in east and north hokkaido, northernmost japan

• Main Author: Hirakawa Kazuomi
• Format: Report
• Language: English
• Published: Department of Geography, Tokyo Metropolitan University 1990
• Subjects: permafrost environment; periglacial phenomena; pollen analysis; freezing and thawing indicies; forest tundra; Ice; permafrost; Tundra; wedge*
• Online Access: https://tokyo-metro-u.repo.nii.ac.jp/?action=repository_uri&item_id=2871; http://hdl.handle.net/10748/3605; https://tokyo-metro-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2871&item_no=1&attribute_id=18&file_no=1

Permafrost environment during the Last Glacial in East and North Hokkaido was examined on the basis of monthly air temperature, the freezing and thawing indicies, and ice wedge casts, comparing them with fossil pollen evidence. The assumed annual mean temperature -8℃ is in great disagreement with field evidence in East Hokkaido. The annual mean temperature ca. -2℃ appears to be more reasonable. Continuous permafrost environment seems to have never occurred in East and North Hokkaido, or northernmost Japan, but discontinuous permafrost under the forest tundra occurred even in the coldest period of the Last Glacial. Ice wedge polygons could be formed under the discontinuous permafrost environment with extraordinarily cold winter, which characterized the climate of northernmost Japan.