Holocene glacier advances in the headwaters of Sredniaya Avacha, Kamchatka, Russia

Holocene glacial deposits in Sredniya Avacha headwaters are subdivided into three age groups (events A, B, and C) based upon geomorphic features, tephrochronology, and lichenometry. Tephras of Opala volcano (1400-1500 yr B.P.), Ksudach volcano (1700-1800 and 6000 yr B.P.), and Zavaritskiy volcano (2800 yr B.P.) are used as stratigraphic markers. Rhizocarpon geographicum (L.) DC and Rhizocarpon section Alpicola growth curves are established using tephrochronologically dated and historical surfaces. The age of event A (pre-Hypsitermal?) moraines is constrained by an age of 6000 yr B.P. for overlying Ksudach-2 tephra and an age of 7200 (?) lichenometric (L) yr B.P. Event B (Neoglaciation) had a multiple nature, with the most prominent advances at 4300-3500, 3300-2800, 2600-2100, 1800-1400, and 1300-1100 (L) yr B.P.; the culmination occurred before 2800 yr B.P., as suggested by a date for Zavaritskiy volcano tephra found on the glacial and outwash deposits. Less-extensive glacier advances of event C ("Little Ice Age"), occurred at 800-600, 500-200, 180-110, and 90-40 L yr B.P. The ELA depression was 200-250, 100-150, 30-70 m during the culmination of events A, B, and C, respectively. (C) 1999 University of Washington.