Holocene pollen record from Lake Sokoch, interior Kamchatka (Russia), and its paleobotanical and paleoclimatic interpretation

• Published in: Global and Planetary Change
• Main Authors: Dirksen, Veronika, Dirksen, Oleg, van den Bogaard, Christel, Diekmann, Bernhard
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2015
• Subjects: Kamchatka Peninsula; Sokoch; Kamchatka; Tundra
• Online Access: https://oceanrep.geomar.de/id/eprint/29840/; https://oceanrep.geomar.de/id/eprint/29840/1/Dirksen.pdf; https://oceanrep.geomar.de/id/eprint/29840/7/mmc1.kml; https://doi.org/10.1016/j.gloplacha.2015.07.010

A pollen record, obtained from sediments of Lake Sokoch in mountain interior of the Kamchatka Peninsula, covers the last ca. 9600. years (all ages are given in calibrated years BP). Variations in local components, including pollen, spores and non-pollen palynomorphs, and related changes in sedimentation document the lake development from initially seepage and shallow basin to deeper lake during the mid Holocene and then to the hydrologically open system during the late Holocene. The studies of volcanic ashes from the lake sediment core show their complex depositional histories.Lake Sokoch occupies a former proglacial basin between two terminal moraines of the LGM time. The undated basal part of record before ca. 9600. year BP, however, does not reflect properly cold conditions. At that time, although shrublands and tundra dominated, stone birch and white birch forests have already settled in surroundings; the presence of alder woodland indicates wet and maritime-like climate. The subsequent forest advance suggesting warmer conditions was interrupted by the ca. 8000-7600. year BP spell of cooler climate. The following culmination of warmth is bracketed by the evidence of the first maximal forest extent between ca. 7400 and 5100. year BP. During that time, dramatic retreat of alder forest suggests a turn from maritime-like to more continental climate conditions. The cool and wet pulse after ca. 5100. year BP was pronounced as forests retreat while shrublands, meadows and bogs extended. An expansion of white birch forest since ca. 3500. year BP reflected the onset of drier climate, strengthening continentality and seasonal contrast. The second maximum of forests dominated by both stone and white birches occurred between ca. 2200 and 1700. year BP and indicated warming in association with relatively dry and increasingly continental climate. The following period was wetter and cooler, and minor outbreak of alder forest around ca. 1500. year BP suggests a short-term return of maritime-like conditions. Since ca. 1300. ...