Holocene Vegetation History of the Verkhoyansk Mountains Foreland, north-eastern Siberia

• Main Authors: Werner, Kirstin, Andreev, Andrei, Diekmann, Bernhard, Kienast, F., Zech, W.
• Format: Conference Object
• Language: unknown
• Published: 2005
• Subjects: Verkhoyansk; Betula nana; Siberia
• Online Access: https://epic.awi.de/id/eprint/13483/; https://epic.awi.de/id/eprint/13483/1/Wer2005e.pdf; https://hdl.handle.net/10013/epic.23864; https://hdl.handle.net/10013/epic.23864.d001

A studied profile from the western foreland of the Verkhoyansk Mountains (65°N, 125°E) provides a high-resolution record of the Holocene vegetation and climate history in north-eastern Siberia between 12.6 and 6.0 cal ka ago. The organic-rich sediments accumulated in a fluvial depositional environment in an oxbow lake between ca 12.6 and 7 cal ka. Peat accumulation started ca. 7 cal ka. The pollen spectra show that larch (Larix dahurica) with shrubs (Betula sect. Nanae and Alnus fruticosa) dominated the vegetation at about 12.6 cal ka (pollen zone (PZ) 1). Picea obovata was probably also present in the vegetation. Poaceae and Cyperaceae associations dominated open habitats. Macroremains of Larix dahurica (cones, seeds, needles and short shoots) from the lower part of the profile are consistent with the pollen record.An increase in the abundance of Artemisia, Chenopodiaceae and Caryophyllaceae pollen in the upper layer (PZ3) shows that steppe-like plant communities were common in the vegetation during the PZ3 interval. The climate was drier than during the previous intervals but the presence of Larix and Pinus pumila pollen points to relatively warm conditions, possibly related to the late Preboreal period.The decline of Artemisia pollen and the increase of Cyperaceae and Picea pollen contents in the lower part of the PZ4 (probably at the beginning of the Boreal period) indicates climate conditions warmer and wetter than during the earlier interval. Founds of pollen of Myriophyllum (an indicator of nutrient-poor water bodies) in the upper part of PZ3 and in the lower part of PZ4 point to the oxbow lake environment. However, founds of remains of insects (Donacia sp. and Saldidae sp.) preferring open water bodies and lake shore vegetation as well as seeds of Menyanthes trifoliata (an indicator of nutrient-poor mires and forested mires) in the middle part of the PZ4 may reflect the gradual transition from oxbow lake to the mire environment.A remarkable increase of Ericales pollen and Sphagnum spores content in the uppermost peat layer (PZ5) reflects a fully established peatland environment after 7 cal ka also documented by the presence of Sphagnum leaves among the plant macrofossils. Climate was relatively warm and wet during this time. The uppermost peat layer contains numerous charcoal particles and Epilobium pollen evidenced a fire event. After this fire, the peatland surface apparently was destroyed and local accumulation stopped.Today larch forest with few other trees (Betula pendula, Picea obovata) and shrubs (Alnus fruticosa, Pinus pumila, Betula nana) dominate the vegetation of this area.