Manon Juliette Andree Bajard

• Zhang, Xu (Yvon); Bajard, Manon Juliette Andree; Bouchez, Julien; Sabatier, Pierre; Poulenard, Jérôme & Arnaud, Fabien [Show all 10 contributors for this article] (2023). Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments. Earth and Planetary Science Letters. ISSN 0012-821X. 624. doi: 10.1016/j.epsl.2023.118463. Full text in Research Archive
• Giguet-Covex, Charline; Bajard, Manon Juliette Andree; Chen, Wentao; Walsh, Kevin James; Pierre-Jerome, Rey & Messager, Erwan [Show all 15 contributors for this article] (2023). Long-term trajectories of mountain agro-ecosystems in the North-Western Alps. Regional Environmental Change. ISSN 1436-3798. 23(58). doi: 10.1007/s10113-023-02030-5.
• Ballo, Eirik Gottschalk; Bajard, Manon Juliette Andree; Støren, Eivind & Bakke, Jostein (2023). Using microcomputed tomography (μCT) to count varves in lake sediment sequences: Application to Lake Sagtjernet, Eastern Norway. Quaternary Geochronology. ISSN 1871-1014. 75. doi: 10.1016/j.quageo.2023.101432. Full text in Research Archive
• Banjan, Mathilde; Christian, Crouzet; Pierre, Sabatier; Hervé, Jomard; Bajard, Manon Juliette Andree & Francois, Demory [Show all 16 contributors for this article] (2022). Did the Younger Dryas to Holocene climate transition favour high seismicity rates in the north-western Alps? Sedimentology. ISSN 0037-0746. 70(2), p. 538–568. doi: 10.1111/sed.13050. Full text in Research Archive
• Bajard, Manon Juliette Andree; Ballo, Eirik Gottschalk; Høeg, Helge Irgens; Bakke, Jostein; Støren, Eivind Wilhelm Nagel & Loftsgarden, Kjetil [Show all 11 contributors for this article] (2022). Climate adaptation of pre-Viking societies. Quaternary Science Reviews. ISSN 0277-3791. 278. doi: 10.1016/j.quascirev.2022.107374. Full text in Research Archive Show summary

  Understanding how the Viking societies were impacted by past climate variability and how they adapted to it has hardly been investigated. Here, we have carried out a new multi-proxy investigation of lake sediments, including geochemical and palynological analyses, to reconstruct past changes in temperature and agricultural practices of pre-Viking and Viking societies in Southeastern Norway during the period between 200 and 1300 CE. The periods 200–300 and 800–1300 CE were warmer than the 300–800 CE period, which is known as the “Dark Ages Cold Period”. This cold period was punctuated by century-scale more temperate intervals, which were dominated by the cultivation of cereals and hemp (before 280 CE, 420–480 CE, 580–700 CE, and after 800 CE). In between, cold intervals were dominated by livestock farming. Our results demonstrate that the pre-Viking societies changed their agricultural strategy in response to climate variability during the Late Antiquity.

• ter Schure, Anneke Theresia Maria; Bajard, Manon Juliette Andree; Loftsgarden, Kjetil; Høeg, Helge Irgens; Ballo, Eirik Gottschalk & Bakke, Jostein [Show all 12 contributors for this article] (2021). Anthropogenic and environmental drivers of vegetation change in southeastern Norway during the Holocene. Quaternary Science Reviews. ISSN 0277-3791. 270. doi: 10.1016/j.quascirev.2021.107175. Full text in Research Archive Show summary

  Uncovering anthropogenic and environmental drivers behind past biological change requires integrated analyses of long-term records from a diversity of disciplines. We applied an interdisciplinary approach exploring effects of human land-use and environmental changes on vegetation dynamics at Lake Ljøgottjern in southeastern Norway during the Holocene. Combined analysis of pollen and sedimentary ancient DNA (sedaDNA) metabarcoding of the sedimentary sequence of the lake describes the vegetation dynamics at different scales, and establishes a timeline for pastoral farming activities. We integrate this reconstruction with geochemical analysis of the sediments, climate data, archaeological evidence of local human settlement and regional human population dynamics. Our data covering the last 10,000 years reveals consistent vegetation signals from pollen and sedaDNA indicating periods of deforestation connected to cultivation, matching the archaeological evidence. Multivariate analysis integrating the environmental data from geochemical and archaeological reconstructions with the vegetation composition indicates that the vegetation dynamics at Lake Ljøgottjern were primarily related to natural processes from the base of the core (in ca. 8000 BCE, Mesolithic) up to the Early Iron Age (ca. 500 BCE–550 CE), when agricultural activities in the region intensified. The pollen signal reflects the establishment of a Bronze Age (ca. 1800–500 BCE) farm in the area, while subsequent intensification of pollen concentrations of cultivated plants combined with the first sedaDNA signals of cultivation and pastoralism are consistent with evidence of the establishment of farming closer to the lake at around 300 BCE. These signals also correspond to the intensification of agriculture in southeastern Norway in the first centuries of the Early Iron Age. Applying an interdisciplinary approach allows us to reconstruct anthropogenic and environmental dynamics, and untangle effects of human land-use and environmental changes on vegetation dynamics in southeastern Norway during the Holocene.

• Bajard, Manon Julietto Andree; Jérôme, Poulenard; Pierre, Sabatier; Yann, Bertrand; Christian, Crouzet & Francesco, Ficetola [Show all 15 contributors for this article] (2019). Pastoralism increased vulnerability of a subalpine catchment to flood hazard through changing soil properties. Palaeogeography, Palaeoclimatology, Palaeoecology. ISSN 0031-0182. 538. doi: 10.1016/j.palaeo.2019.109462. Full text in Research Archive Show summary

  Soil erosion is strongly linked to both precipitation patterns and land-use. We examine the effects of erosion and its drivers (i.e. human or/and climate) on soil evolution from the study of lacustrine archives in the northern French Alps. Multi-proxy analyses of the Lake Gers sediment sequence combined with the study of soils and rocks of its catchment allowed to reconstruct its evolution over the past 4.6 kyr. This included 14C dating, short-lived radionuclides, geochemistry, loss on ignition, grain-size analyses, as well as plant and mammal DNA analyses. A total of 127 instantaneous deposits were identified among the continuous sedimentation in the lake and 93 were interpreted as flood deposits. Erosion was quantified for the whole catchment considering both the continuous sedimentation and the flood deposit thicknesses. The catchment is mainly formed by andesitic sandstones over which Andosols and Podzols can develop. However, low weathered materials from colluviation constitute the main input to the lake. Four main phases of changes in soil weathering were recorded by increases in K2O/TiO2 ratios, associated with an increase in both erosion and flood-frequency. Two phases were associated with climate cooling in the Western Alps, from 2.65 to 2.5 and from 1.45 to 1.3 cal kyr BP. The two others (1.9–1.75 and 0.9–0.4 cal kyr BP) were triggered with deforestation, with cow grazing during the Roman period, and with grazing of cows, sheep and goats during the Medieval period, amplified by the onset of the Little Ice Age. The increase in erosion and flood frequency after 950 cal yr BP indicates substantial damages to soils of the catchment including increase of their erodibility over the last millennia.

• Giguet-Covex, Charline; Ficetola, Francesco; Walsh, Kevin; Poulenard, Jerome; Bajard, Manon Julietto Andree & Fouinat, Laurent [Show all 16 contributors for this article] (2019). New insights on lake sediment DNA from the catchment: importance of taphonomic and analytical issues on the record quality. Scientific Reports. ISSN 2045-2322. 9(1). doi: 10.1038/s41598-019-50339-1.
• Christian, Crouzet; Bruno, Wilhelm; Pierre, Sabatier; Francois, Demory; Nicolas, Thouveny & Cecile, Pignol [Show all 12 contributors for this article] (2019). Palaeomagnetism for chronologies of recent alpine lake sediments: successes and limits. Journal of Paleolimnology. ISSN 0921-2728. 62(3), p. 259–278. doi: 10.1007/s10933-019-00087-z.
• Bajard, Manon Julietto Andree; David, Etienne; Sebastien, Quinsac; Etienne, Dambrine; Pierre, Sabatier & Victor, Frossard [Show all 11 contributors for this article] (2018). Legacy of early anthropogenic effects on recent lake eutrophication (Lake Bénit, northern French Alps). Anthropocene. ISSN 2213-3054. 24, p. 72–87. doi: 10.1016/j.ancene.2018.11.005.

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• Bajard, Manon Juliette Andree (2022). Agricultural and climatic contexts associated to the Fimbulwinter in the area of Gardermoen: when pre-Viking societies adapted to the climate.
• Ballo, Eirik Gottschalk; Bajard, Manon Juliette Andree; Bakke, Jostein; Støren, Eivind Wilhelm Nagel; D'Andrea, William J. & Høeg, Helge Irgens (2022). Lake Sagtjernet hydrogen isotopes and pollen .
• Ballo, Eirik Gottschalk; Bajard, Manon Juliette Andree; Bakke, Jostein & Støren, Eivind Wilhelm Nagel (2021). Using CT scans to count varves: Application to Lake Sagtjernet.
• Ballo, Eirik Gottschalk; Bajard, Manon Juliette Andree; Bakke, Jostein & Støren, Eivind Wilhelm Nagel (2021). Using CT scans to count varves in Lake Sagtjernet.
• Bajard, Manon Juliette Andree (2021). PC1. Improving food security: new techniques. [Internet]. Press conference/EGU General Assembly 2021. Show summary

  "In 2019, nearly 750 million people were exposed to severe levels of food insecurity. Conservative estimates indicate that more than 3 billion people can’t afford healthy diets, and that the social costs of greenhouse gas emissions associated with current food-consumption patterns will top $1.7 trillion per year within the next decade. This press conference will introduce journalists to some of the latest geoscience research being conducted to help improve global food security, including two types of forecasting that support early warnings in Africa. Additional research strives to improve agricultural management strategies with respect to greenhouse gas emissions and to balance food and water security in cities. Lastly, we will hear how one group of scientists is researching how pre-Viking and Viking societies adapted their agricultural practices to a changing climate to glean fresh insights into how we can improve our future food security." (EGU: 2021)

• Bajard, Manon Juliette Andree & Dacey, James (2021). Food Security Lessons from the Vikings. [Journal]. EOS Science News by AGU. Show summary

  Scandinavian societies of the first millennium adapted their farming practices to volcano-driven climate changes.

• Bajard, Manon Juliette Andree (2021). PC1. Improving food security: new techniques. [Journal]. Press conference/EGU General Assembly 2021.
• ter Schure, Anneke; Bajard, Manon Julietto Andree; Loftsgarden, Kjetil; Høeg, Helge Irgens; Ballo, Eirik Magnus Gottschalk & Bakke, Jostein [Show all 12 contributors for this article] (2021). Disentangling anthropogenic and environmental drivers of biological change in southeastern Norway during the Holocene.
• ter Schure, Anneke; Bajard, Manon Julietto Andree; Loftsgarden, Kjetil; Høeg, Helge Irgens; Ballo, Eirik Magnus Gottschalk & Bakke, Jostein [Show all 12 contributors for this article] (2021). Anthropogenic and environmental drivers of biological change in southeastern Norway during the Holocene.
• Bajard, Manon Julietto Andree; Ballo, Eirik Magnus Gottschalk; Høeg, Helge I.; Bakke, Jostein; Støren, Eivind N. & Loftsgarden, Kjetil [Show all 11 contributors for this article] (2021). Instability or adaptation of the pre-Viking society to the climate variability of the Late Antiquity? Show summary

  Understanding how agricultural societies were impacted and adapted to past climate variations is critical to adapt to contemporary climate change and guaranty the food security. However, linking climate and change in the behaviour of a population are difficult to evidence. Here, we studied the climate variations of the period between 200 and 1300 CE and its impact on the pre-Viking and Viking societies in south Norway. We used a retrospective approach combining a multi-proxy analysis of lake sediments, including geochemical and palynological analyses, to reconstruct past changes in temperature and agricultural practices during the period 200-1300 CE. We associated variations in Ca/Ti ratio as a result of change in lake productivity with the temperature. The periods 200-300 and 800-1300 CE were warmer than the period between 300 and 800 CE, which is known as the “Dark Ages Cold Period” in the Northern Hemisphere. During this colder period, phases dominated by grazing activities (280-420 CE, 480-580 CE, 700-780 CE) alternated with phases dominated by the cultivation of cereals and hemp (before 280 CE, 420-480 CE, 580-700 CE, and after 800 CE). The alternation of these phases is synchronous of temperature changes. Cold periods are associated to livestock farming, and warmer periods to crop farming. This result suggests that when temperature no longer allowed crop farming, the food production specialized in animal breeding. The development of activities reached a maximum between 400 and 550 CE and a minimum between 680 and 800 CE, in agreement with archaeological findings. The Viking Age (800-1000 CE) started with an increase in temperature and corresponds to the warmest period between 200 and 1300 CE, allowing a larger development of the agriculture practices and society. Our results prove that the pre-Viking society adapted their agricultural practices to the climate variability of the Late Antiquity and that the Vikings expanded with climate warming.

• Bajard, Manon Julietto Andree (2020). The hidden face of lakes: how natural archives bring us back to the Viking Age and beyond. Show summary

  Since 10,000 years, lakes have continuously accumulated sediments. These sediments contain particles of soil, plant, pollen and DNA from the surrounding environment, brought by rivers, runoff and the wind. They allow us to reconstruct the past evolution of the landscapes, the vegetation and agricultural practices, but also climate changes. By studying and dating cores of lake sediments in Norway, we can reconstruct the history of the environment throughout the last 10 000 years and explore the Viking Age.

• Bajard, Manon Julietto Andree; Ballo, Eirik Magnus Gottschalk; Støren, Eivind Wilhelm Nagel; Bakke, Jostein; Høeg, Helge Irgens & Loftsgarden, Kjetil [Show all 8 contributors for this article] (2020). Volcanic Eruptions and their Impacts on Climate, Environment, and Viking Society in 500-1250 CE .
• Bajard, Manon Julietto Andree; Ballo, Eirik Magnus Gottschalk; Støren, Eivind Wilhelm Nagel; Bakke, Jostein; Høeg, Helge Irgens & Loftsgarden, Kjetil [Show all 9 contributors for this article] (2020). Record of climate and environmental changes in a dead-ice lake close to Gardermoen told by a 10 000 years old freshwater fish and a Viking King. Show summary

  We studied a six-meter long sediment sequence retrieved from the kettle lake Ljøgottjern, close to Oslo-Gardermoen Airport, to reconstruct environmental and climate changes during the last millennia. The lake is 18 m depth and located at 185 m a.s.l., under the maximum postglacial sea level. The largest burial mound of Northern Europe was built in the mid-6th century on the shore of this lake allegedly for King Rakni and makes this place ideal to study human-environment interactions in a paleo-perspective approach. Using a multi-proxy sedimentological analysis of this record, including 14C dating, paleo-secular variations, XRF and CT scans, and pollen, this study highlights different climate patterns throughout the Holocene. At the bottom of the core, a carbonated sandy-clayey layer with centimetric twigs overlays an organic rich black peaty-type layer, suggesting a continental environment. On top of that, a disturbed clay layer containing fish bones from a freshwater Carpinidae species was found. The fish could have been buried by the massive (70 cm) sandy carbonated deposit covering it. A sharp transition separates a clay cap on top of the deposit and the start of a finely laminated lacustrine sedimentation dated 9.3 ka cal. BP. The massive deposit could be associated to the outburst flood from the glacial lake Nedre Glomsjø dated 10-10.4 ka cal BP (Longva, 1984; Høgaas and Longva, 2016). A major change in the sedimentation occurred around 8 ka cal. BP, with darker sediments and a lower sedimentation rate. This change could be related to a warming climate and stabilization of the catchment by soil and forest development around the lake in the mid-Holocene. The sedimentation rate increased again between 2000 and 3000 years cal. BP as a result of the development of first human activities and major change in the vegetation (Høeg, 1997). We reconstructed temperature changes during the first millennia and compared it to societal dynamics. The period between 300 and 800 years cal. CE is colder than the period 800-1300 years cal. CE. After 1600 years cal. CE, an increase in erosion could be associated to the extension of the population and agriculture in Scandinavia and revealed a chronicle of the major floods in this area. The presence of freshwater fish older than 9,3 ka attests of their early and natural colonization of Scandinavian lakes. The comparison of this record with archaeological data will allow us to discuss socio-environmental dynamics following the deglaciation in the area. References: Smith, A.A. 2010. CO2 stor¬age. Journal of Sciences 32, 10-20. Høeg, H.I., 1997. Pollenanalytiske undersøkelser på Øvre Romerike : Ullensaker og Nannestad, Akershus fylke : Gardermoprosjektet, Varia (Universitetets oldsaksamling : trykt utg.). Universitetets oldsaksamling, Oslo. Høgaas, F., Longva, O., 2016. Mega deposits and erosive features related to the glacial lake Nedre Glomsjø outburst flood, southeastern Norway. Quat. Sci. Rev. 151, 273–291. https://doi.org/10.1016/j.quascirev.2016.09.015 Longva, O., 1984. Romeriksmjelen danna ved ein storflaum på Austlandet for vel 9000 år siden. Norges geologiske undersøkelse, Årsmelding 1984 8–11.

• Bajard, Manon Julietto Andree; Ballo, Eirik Magnus Gottschalk; Støren, Eivind Wilhelm Nagel; Bakke, Jostein; Høeg, Helge Irgens & Loftsgarden, Kjetil [Show all 9 contributors for this article] (2020). Tracing socio-environmental dynamics and climate changes in the period 300-1300 CE in Scandinavia from lake sediments. Show summary

  Understanding large volcanic eruptions impacts on environments and societies is necessary to consider future climate and socio-environmental interactions. Lake sediments can record these dynamics on a continuous long time scale and include at the same time footprints from volcanic eruptions, climate changes and human activities. We analysed the sediments of Lake Ljøgottjern, located southeastern Norway. The largest burial mound of Northern Europe was built in the mid-6th century on the shore of this lake and makes this place an ideal site to study human-environmental interactions throughout the last millennia. Using a multi-proxy analysis of this sedimentary record, including 14C dating, geochemistry, as well as palynological data, we reconstructed temperature and socio-environmental changes in this area between 300 and 1300 CE (Common Era). We associated changes in Ca/Ti ratio with changes in temperature. The period between 300 and 800 CE was colder than the periods 200-300 and 800-1300 CE. Five abrupt cooling events seem to be linked to weakened positive NAO (North Atlantic Oscillation) phases, and two of them can also be linked to the two largest volcanic events of the period (i.e. the 536/540 CE double event, and 1257 CE eruption of Samalas). Palynological data indicate a decrease of the human activities and reforestation of the area in the 6th century. This abandonment is consistent with archaeological findings and could be related to the 536/540 cooling event. Very little activities are then recorded between 700 and 850 CE. Agricultural activities start again strongly in the Viking age with increase in temperature.

• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Bakke, Jostein & Støren, Eivind Wilhelm Nagel (2019). Reconstructing climate and socio-environmental changes using lake sediments .
• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Bakke, Jostein & Støren, Eivind Wilhelm Nagel (2019). Reconstructing climate and socio-environmental changes using lake sediments .
• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Bakke, Jostein & Støren, Eivind Wilhelm Nagel (2019). Reconstructing climate and socio-environmental changes using lake sediments .
• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Støren, Eivind Wilhelm Nagel; Bakke, Jostein & Svensen, Henrik (2019). High-resolution lacustrine records of environmental changes in Scandinavia: a focus on the Migration period and Viking age.
• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Støren, Eivind Wilhelm Nagel; Bakke, Jostein & Svensen, Henrik (2019). High-resolution lacustrine records of environmental changes in Scandinavia: a focus on the Migration period and Viking age.
• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Støren, Eivind Wilhelm Nagel; Bakke, Jostein & Svensen, Henrik (2019). High-resolution lacustrine records of environmental changes in Scandinavia: a focus on the Migration period and Viking age.
• Ballo, Eirik Magnus Gottschalk; Bajard, Manon Julietto Andree; Støren, Eivind Wilhelm Nagel; Bakke, Jostein & Svensen, Henrik (2019). High-resolution lacustrine records of environmental changes in Scandinavia: a focus on the Migration period and the Viking age.
• Bajard, Manon Julietto Andree; Støren, Eivind Wilhelm Nagel; Bakke, Jostein & Svensen, Henrik (2019). High-resolution lacustrine records of environmental changes in Scandinavia: a focus on the Migration period and Viking age.
• Bajard, Manon Julietto Andree & Eirik, Ballo (2019). First insight in Norwegian sedimentary archives .
• Bajard, Manon Julietto Andree; Jérôme, Poulenard; Pierre, Sabatier; Anne-Lise, Develle; Fernand, David & Jacques-Louis, De Beaulieu [Show all 17 contributors for this article] (2019). Non-linear soil evolution trajectories from the Holocene to the Anthropocene. Show summary

  Soils have a substantial role in the environment as they give back several ecosystem services as food supply and carbon storage. But agricultural practices can modify soil properties and soil evolution processes, threatening these services. These modifications are poorly studied and resilience/adaptation times of soils to disruptions are unknown on pedogenesis time scale. Lake sediment sequences can be used as continuous archives of long soil evolution. The study of four lake-catchment systems from the western North Alps inquires both soil evolution and the development of human activities throughout the Holocene. The compared multiproxy analysis of sedimentary sequences of Lake La Thuile (875 m, Bauges), Lake Bénit (1450 m, Bargy), Lake Gers (1540 m, Giffre), Lake Verney (2088 m, Italy, Petit Saint-Bernard Pass) and the soils of their catchment, allowed to decipher the interactions between agro-pastoral system, erosion and soils. Our main objective is to determine whether human became, over the Holocene, the overriding factor of the pedogenesis and what are the ecosystem responses to disruptions, in terms of resilience and sustainability. The comparison of paleoenvironmental reconstructions, derived from lacustrine archives evidenced a progressive development of soils during the first part of the Holocene, associated with substrate decarbonatation, acidification then podzolization of soils in the Holocene Climate Optimum. The second part of the Holocene is characterized by regressive pedogenesis, in response to agro-pastoral activities development, mainly around the Roman and Medieval periods, along with erosion increases. Environmental disruptions triggered colluviation movements and a regression of soil weathering, leading to a multiplication of (non-linear) soil evolution trajectories and a higher soil diversity in the Anthropocene.

• Bajard, Manon Julietto Andree; Eirik, Ballo; Jostein, Bakke; Eivind, Støren; Helge, Høeg & Frode, Iversen [Show all 8 contributors for this article] (2019). Socio-environmental dynamics and volcanic eruptions in the 500-1250 CE period in Scandinavia: new sight in Lake Ljøgottjern sediment sequence. Show summary

  Large volcanic eruptions are the major drivers of climate variability in the pre-industrial era of the last two millennia. Understanding their impacts on societies is necessary to consider future climate and socio-environmental interactions. Lake sediments can record these dynamics on a continuous time scale and include at the same time footprints from volcanic eruptions, climate changes and human activities associated to vegetation changes. Lake Ljøgottjern is located in southeastern Norway and is of glacial origin. The lake is 18 m depth, groundwater-fed and provide a sediment sequence covering the last 8000 years. The largest burial mound of Norway was built in the mid-6th century on the shore of this lake for King Rakni and makes this place an ideal site to study human-environmental interactions throughout the last millennia, confronting them to archaeological evidences. Using a high-resolution multi-proxy analysis of this record, including 14C dating, sedimentological and both mineral and organic geochemical analyses as well as palynological data, this study will allow reconstructing climate and socio-environmental changes in this area, with a focus on the 500-1250 CE (Common Era) period. A previous palynological study evidenced the first openings of the environment linked to the development of agriculture between 3000 and 3500 yrs cal. BP. This change in land use was associated with changes in the geochemistry of the sediment. Maximum anthropogenic impacts were recorded in ca. 600 CE, when the mound was raised, and in the Little Ice Age, between the 13th and 17th centuries. The pollen diagram of Lake Ljøgottjern presents also three substantial decreases in charcoal particles between 500 and 1250 CE. An updated and high resolution dating of the new sequence will allow to associate or not these changes in fire regimes to major volcanic events (i.e., 536-540 unknown, 939 Eldgjà and 1257 Samalas). The comparison of this record with other environmental archives from Norway, as well as climate reconstructions from ice cores and tree rings will allow us to discuss resilience times and adaptation of the Viking society in a changing Scandinavian environment.

• Bajard, Manon Julietto Andree; Eirik, Ballo; Jostein, Bakke; Eivind, Støren; Helge, Høeg & Frode, Iversen [Show all 8 contributors for this article] (2019). Socio-environmental dynamics and volcanic eruptions in the 500-1250 CE period in Scandinavia: new sight in Lake Ljøgottjern sediment sequence. Show summary

  Large volcanic eruptions are the major drivers of climate variability in the pre-industrial era of the last two millennia. Understanding their impacts on societies is necessary to consider future climate and socio-environmental interactions. Lake sediments can record these dynamics on a continuous time scale and include at the same time footprints from volcanic eruptions, climate changes and human activities associated to vegetation changes. Lake Ljøgottjern is located in southeastern Norway and is of glacial origin. The lake is 14 m depth, groundwater-fed and provide a sediment sequence covering the last 8000 years. The largest burial mound of Norway was built in the mid-6th century on the shore of this lake for King Rakni and makes this place an ideal site to study human-environmental interactions throughout the last millennia, confronting them to archaeological evidences. Using a high-resolution multi-proxy analysis of this record, including 14C dating, sedimentological and both mineral and organic geochemical analyses as well as palynological data, this study will allow reconstructing climate and socio-environmental changes in this area, with a focus on the 500-1250 CE (Common Era) period. A previous palynological study evidenced the first openings of the environment linked to the development of agriculture between 3000 and 3500 yrs cal. BP. This change in land use was associated with changes in the geochemistry of the sediment. Maximum anthropogenic impacts were recorded in ca. 600 CE, when the mound was raised, and in the Little Ice Age, between the 13th and 17th centuries. The pollen diagram of Lake Ljøgottjern presents also three substantial decreases in charcoal particles between 500 and 1250 CE. An updated and high resolution dating of the new sequence will allow to associate or not these changes in fire regimes to major volcanic events (i.e., 536-540 unknown, 939 Eldgjà and 1257 Samalas). The comparison of this record with other environmental archives from Norway, as well as climate reconstructions from ice cores and tree rings will allow us to discuss resilience times and adaptation of the Viking society in a changing Scandinavian environment.

• Svensen, Henrik; John, Timm; Weyer, Stefan; Fristad, Kirsten; Polozov, Alexander & Bajard, Manon Julietto Andree [Show all 8 contributors for this article] (2019). Bacterial sulphate- and iron reduction in a Siberian Traps crater lake during the end-Permian crisis .
• Krüger, Kirstin & Bajard, Manon Julietto Andree (2019). Volcanic Eruptions and their Impacts on Climate, Environment, and Viking Society in 500-1250 CE . Show summary

  VIKINGS(NFR) TACCO(Notur/NorStore)

• Bajard, Manon Julietto Andree; Eirik, Ballo; Henrik, Svensen; Helge, Høeg; Frode, Iversen & Jostein, Bakke [Show all 7 contributors for this article] (2018). Norwegian lakes and what they can tell us about the Vikings .
• Bajard, Manon Julietto Andree & Kirstin, Krüger (2018). VIKINGS Project Volcanic Eruptions and their Impacts on Climate, Environment, and Viking Society in 500-1250 CE .

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