Northern Eurasian large lakes history: sediment records obtained in the frame of Russian-German research project PLOT

Russian-German project PLOT (Paleolimnological Transect) aims at investigating the regional responses of the quaternary climate and environment on external forcing and feedback mechanisms along a more than 6000 km long longitudinal transect crossing Northern Eurasia. The well-dated record from Lake El´gygytgyn used as reference site for comparison the local climatic and environmental histories. Seismic surveys and sediment coring up to 54 m below lake floor performed in the frame of the project on Ladoga Lake (North-West of Russia; 2013), Lake Bolshoye Shchuchye (Polar Ural; 2016), Lake Levinson-Lessing and Lake Taymyr (Taymyr Peninsula; 2016-2017), Lake Emanda (Verkhoyansk Range; 2017). Fieldwork at Polar Ural and Taymyr Peninsula was conducted in collaboration with the Russian-Norwegian CHASE (Climate History along the Arctic Seaboard of Eurasia) project. Here, we present the major results of the project obtained so far

Lateglacial and Holocene environmental history of the central Kola region, northwestern Russia revealed by a sediment succession from Lake Imandra

Bolshaya Imandra, the northern sub-basin of Lake Imandra, was investigated by a hydro-acoustic survey followed by sediment coring down to the acoustic basement. The sediment record was analysed by a combined physical, biogeochemical, sedimentological, granulometrical and micropalaeontological approach to reconstruct the regional climatic and environmental history. Chronological control was obtained by 14C dating, 137Cs, and Hg markers as well as pollen stratigraphy and revealed that the sediment succession offers the first continuous record spanning the Lateglacial and Holocene. Following the deglaciation prior to c. 13 200 cal. a BP, the lake's sub-basin initially was occupied by a glacifluvial river system, before a proglacial lake with glaciolacustrine sedimentation established. Rather mild climate, a sparse vegetation cover and successive retreat of the Scandinavian Ice Sheet (SIS) from the lake catchment characterized the Bølling/Allerød interstadial, lasting until 12 710 cal. a BP. During the subsequent Younger Dryas chronozone, until 11 550 cal. a BP, climate cooling led to a decrease in vegetation cover and a re-advance of the SIS. The SIS disappeared from the catchment at the Holocene transition, but small glaciers persisted in the mountains at the eastern lake shore. During the Early Holocene, until 8400 cal. a BP, sedimentation changed from glaciolacustrine to lacustrine and rising temperatures caused the spread of thermophilous vegetation. The Middle Holocene, until 3700 cal. a BP, comprises the regional Holocene Thermal Maximum (8000–4600 cal. a BP) with relatively stable temperatures, denser vegetation cover and absence of mountain glaciers. Reoccurrence of mountain glaciers during the Late Holocene, until 30 cal. a BP, presumably results from a slight cooling and increased humidity. Since c. 30 cal. a BP Lake Imandra has been strongly influenced by human impact, originating in industrial and mining activities. Our results are in overall agreement with vegetation and climate reconstructions in the Kola region

Multi-proxy data set of the sediment core Co1410 from Lake Imandra, NW Russia

The sediment succession of Lake Imandra in the central Kola region was investigated by a hydro-acoustic survey followed by sediment coring of site Co1410 (67°42'56.76"N, 33°5'6.42"E) down to the acoustic basement. We reconstructed the environmental history of Lake Imandra after the last deglaciation based on physical, biogeochemical, sedimentological, granulometrical, and micropalaeontological proxies. Our findings reveal the timing of the onset of lacustrine sediment deposition in the lake basin during the Late Glacial and the variability of climatic signals throughout the Holocene. All datasets comprise a depth and age column and: 1. S = Sulfur (%); TOC = Total Organic Content (%); TOC/TN = Total Organic Content / Total Nitrogen; Water Content (%); Grain Size d50 (µm); EM1 =Endmember 1 (%); EM2 =Endmember 2 (%); EM3 = Endmember 3 (%) 2. Acroperus harpae; Alona affinis; Alona guttata/Coronatella rectangula; Alona intermedia; Alona quadrangularis; Alona rustica; Alonella excisa; Alonella exigua; Alonella nana; Alonopsis elongata; Bosmina (Bosmina) longirostris; Bosmina (Eubosmina) cf. longispina/cf. coregoni; Chydorus cf. sphaericus; Daphnia longispina agg.; Eurycercus sp. Leptodora kindtii; Monospilus dispar; Paralona pigra; Pleuroxus truncatus; Rhynchotalona falcata; Planktonic; Littoral-benthic ; (%) Acroperus harpae; (%) Alona affinis; (%) Alona guttata/Coronatella rectangula; (%) Alona intermedia; (%) Alona quadrangularis; (%) Alona rustica; (%) Alonella excisa; (%) Alonella exigua; (%) Alonella nana; (%) Alonopsis elongata; (%) Bosmina (Bosmina) longirostris; (%) Bosmina (Eubosmina) cf. longispina/cf. coregoni; (%) Chydorus cf. sphaericus; (%) Daphnia longispina agg.; (%) Eurycercus sp.; (%) Leptodora kindtii; (%) Monospilus dispar; (%) Paralona pigra; (%) Pleuroxus truncatus; (%) Rhynchotalona falcata 3. magnetic susceptibility (SI * 10^-5) 4. Pinus(%); Artemisia (%); Total Pollen Concentration /1000; AP/NAP; Arboreale Pollen (%); Non-Arboreale Pollen (%) 5. Zr/Rb (log); Rb/Sr; Zr/Al; K/Al; Ti (cps); Ti/Al; Si (cps); Si/Ti; Br/Al; Fe (cps); Fe/M

Lateglacial and Holocene environmental history of the central Kola region, northwestern Russia revealed by a sediment succession from Lake Imandra

Bolshaya Imandra, the northern sub-basin of Lake Imandra, was investigated by a hydro-acoustic survey followed by sediment coring down to the acoustic basement. The sediment record was analysed by a combined physical, biogeochemical, sedimentological, granulometrical and micropalaeontological approach to reconstruct the regional climatic and environmental history. Chronological control was obtained by(14)C dating,Cs-137, and Hg markers as well as pollen stratigraphy and revealed that the sediment succession offers the first continuous record spanning the Lateglacial and Holocene. Following the deglaciation prior toc. 13 200 cal. aBP, the lake's sub-basin initially was occupied by a glacifluvial river system, before a proglacial lake with glaciolacustrine sedimentation established. Rather mild climate, a sparse vegetation cover and successive retreat of the Scandinavian Ice Sheet (SIS) from the lake catchment characterized the Bolling/Allerod interstadial, lasting until 12 710 cal. aBP. During the subsequent Younger Dryas chronozone, until 11 550 cal. aBP, climate cooling led to a decrease in vegetation cover and a re-advance of theSIS. TheSISdisappeared from the catchment at the Holocene transition, but small glaciers persisted in the mountains at the eastern lake shore. During the Early Holocene, until 8400 cal. aBP, sedimentation changed from glaciolacustrine to lacustrine and rising temperatures caused the spread of thermophilous vegetation. The Middle Holocene, until 3700 cal. aBP, comprises the regional Holocene Thermal Maximum (8000-4600 cal. aBP) with relatively stable temperatures, denser vegetation cover and absence of mountain glaciers. Reoccurrence of mountain glaciers during the Late Holocene, until 30 cal. aBP, presumably results from a slight cooling and increased humidity. Sincec. 30 cal. aBPLake Imandra has been strongly influenced by human impact, originating in industrial and mining activities. Our results are in overall agreement with vegetation and climate reconstructions in the Kola region