[H-CG36] [JJ] Coastal wetlands: geomorphologic, biologic and anthropogenic processes

[HCG36-P04] Vegetation change viewed from pollen analysis around Haven Lake in Adak Island, Central Aleutians, Alaska

*Makoto Noguchi¹, Toshiyuki Fujiki¹, Mitsuru Okuno², Lyn Guiltieri³, Burenn Sarata⁴, Masayuki Torii⁵, Keiji Wada⁶, Toshio Nakamura⁷, Dixie West⁸ (1.Okayama Univ. Science, 2.Fukuoka Univ., 3.Seattle Univ., 4.Fugro NV, The Netherlands, 5.Kumamoto Univ., 6.Hokkaido Univ. Education, 7.Nagoya Univ., 8.Kansas Univ.)

Keywords:tephra, pollen analysis, vegetation change, peaty sediments, charcoal chip

To determine vegetation change in Adak Island (central Aleutians), we collected peaty sediments (ADK13083002 Core) from Haven Lake in the island. We confirmed six apparent tephra layers (Black, 1976), 40 Years (0.4 cal kBP), YBO (3.6 cal kBP), Sandwich (4.7 cal kBP), Intermediate (7.2 cal kBP) and Main (9.5 cal kBP) and Upper and Lower Gritty (ca. 10 kBP). Four major pollen assemblage zones (HL-1 to -4 in descending order) are recognized in the cored sediments. The HL-1 pollen zone is dominated by Ranunclaceae and Empetrum. The HL-2 pollen zone is dominated by Poaseae, Ranunclaceae, and Empetrum. The HL-3 pollen zone is dominated by Poaseae and Empetrum. The HL-4 pollen zone is dominated by Poaseae, Cyperaceae, Empetrum and Lycopodiaceae. The charcoal chips increased above Intermediate Tephra. It's contemplated that the Aleut people arrived at Adak Island and started settling down from ca. 9.5 cal kBP.