OSL Dating of the Sukor Earthquake-induced Rockslide in Gorny Altai: Paleoseismological and Paleogeographic Implications

Abstract —Lacustrine sediments, related subaerial aeolian sands, as well fluvioglacial sands enclosed in ablation moraines the Chuya River valley between and Kurai basins Gorny Altai, have been dated by optically stimulated (OSL) infrared (IRSL) luminescence. The OSL IRSL ages indicate that formation of lake, which spread into Basin, was caused Sukor rockslide dammed Valley. triggered a large earthquake (shaking intensity at least IX-X) generated an active fault Fault Zone about 16 ka, is oldest known date for its activity. Thus, landslides or rockslides can remain geomorphically expressed ka climate landscape conditions basins. lake existed till ~10 BP then gradually drained. Kuyuktanar glacier reached greatest extent early marine isotope stage (MIS) 2, formed 25 ka. Judging age good preservation left glacier, hilly terrain area rockslide, presence lacustrine vicinity dam, no catastrophic flooding events Katun valleys occurred since Last Glacial Maximum (LGM; ~20 kyr BP). water table glacier-dammed occupied Basin around LGM could not exceeded 1750 m above sea level (a.s.l.). Higher terraces traceable elevations 2100–2200 a.s.l. should be attributed to more ancient stages. Archaeological sites junction were post-lake period, dating back latest Late Paleolithic time.