Deglaciation history of Lake Ladoga (northwestern Russia) based on varved sediments

Abstract

Lake Ladoga in northwestern Russia is Europe's largest lake. The postglacial historyof the Ladogabasin is for the first time documented continuously with high temporal resolution in the upper 13.3 m of a sediment core (Co1309) from the northwestern part of the lake. We applied a multiproxy approach including radiographic imaging, (bio-) geochemical and granulometric analyses. Age control was established combining radiocarbon dating with varve chronology, the latter anchored to a correlated radiocarbon age from a lake close by. The age-depth model reveals the onset of glacial varve sedimentation at 13 910AE140 cal. a BP, when Lake Ladoga was part of the Baltic Ice Lake. Linear extrapolation of published retreat rates of the Scandinavian Ice Sheet provides a formation age of the Luga moraine close to Lake Ladoga's southern shore of 14.5-15.9 cal. ka BP, older than previously assumed. Varve sedimentation covers the Bølling/Allerød interstadial, the Younger Dryas stadial and the Early Holocene. Varvethickness variations, conjoined with grain-size and geochemical variations, inform about the relative position of the Scandinavian Ice Sheet and the climate during the deglaciation phase. The upper limit of the varved succession marks the change from glaciolacustrine to normal lacustrine sedimentation and post-dates the drainage of the Baltic Ice Lake aswell as the formation of the Salpausselk€ a II moraine north of Lake Ladoga, by c. 250 years. The Holocene sediment record is divided into three periods in the following order: (i) a lower transition zone between the Holocene boundary and c. 9.5 cal. ka BP, characterized by mostly massive sediments with low organic content, (ii) a phase with increased organic content from c. 9.5 to 4.5 cal. ka BP corresponding to the Holocene Thermal Maximum, and (iii) a phase with relatively stable sedimentation in a lacustrine environment from c. 4.5 cal. ka BP until present.

Seismic stratigraphical record of Lake Levinson‐Lessing, Taymyr Peninsula: evidence for ice‐sheet dynamics and lake‐level fluctuations since the Early Weichselian

“…In the framework of the joint Russian-German project PLOT (Paleolimnological Transect), extensive fieldwork, including seismic surveys, coring, and hydrological investigations, was carried out, between 2013 and 2017, at lakes Ladoga (NW Russia, Andreev et al 2019;Gromig et al 2019), Bolshoye-Shuchye (Polar Urals), Emanda (Verkhoyansk Range), and Levinson-Lessing (this paper) and Taymyr (both Taymyr Peninsula). The project aims at recovering lacustrine sediment successions along a >6000km-long longitudinal transect across the Russian Arctic to investigate the late Quaternary climatic and environmental history, with a special emphasis on recovering preglacial sediments.…”

Vegetation and climate changes in northwestern Russia during the Lateglacial and Holocene inferred from the Lake Ladoga pollen record

“…Four OSL dates and two 14 C dates were excluded from the interpretation, as they are much older than suggested by the varve and pollen stratigraphy. We confidently conclude that these dates are incorrect and assume that they overestimate the real ages due to insufficient bleaching of the quartz grains and redeposition of older organic matter, respectively (for details see Gromig et al 2019). In the Holocene part of the record, one OSL date (7.0AE0.3 ka BP) and two 14 C dates (7559AE70 and 2547AE171 cal.…”

“…a BP). For more details concerning the dating techniques and for the age-depth model see Gromig et al (2019).…”

“…The sediment succession Co1309 (22.75 m) was subdivided into five main lithological zones (LZs), which are described in detail in Gromig et al (2019) and Andreev et al (2019;Fig. 2).…”

“…ka BP, shortly after Lake Ladoga became permanently ice free (13.3 m b.l.f. ; Gromig et al 2019). The lowermost part of LZ IV (13.3-12.75 m b.l.f.…”