Correlation of Swedish glacial varves with the Greenland (GRIP) oxygen isotope record

Andrén, Thomas; Björck, Jonas; Johnsen, S. J.

doi:10.1002/(sici)1099-1417(199907)14:4<361::aid-jqs446>3.0.co;2-r

Cited by 85 publications

(80 citation statements)

References 24 publications

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“…1a,c). Isochrons ( ± 150 y uncertainty) are tied to the Swedish clay-varve chronology and correlated with the Greenland Ice Core Project (GRIP) chronology 43 , and the timing of final deglaciation is independently confirmed by cosmogenic exposure dating. The isochron map (Fig.…”

Section: Methodsmentioning

confidence: 99%

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Inner gorges cut by subglacial meltwater during Fennoscandian ice sheet decay

et al. 2014

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The century-long debate over the origins of inner gorges that were repeatedly covered by Quaternary glaciers hinges upon whether the gorges are fluvial forms eroded by subaerial rivers, or subglacial forms cut beneath ice. Here we apply cosmogenic nuclide exposure dating to seven inner gorges along B500 km of the former Fennoscandian ice sheet margin in combination with a new deglaciation map. We show that the timing of exposure matches the advent of ice-free conditions, strongly suggesting that gorges were cut by channelized subglacial meltwater while simultaneously being shielded from cosmic rays by overlying ice. Given the exceptional hydraulic efficiency required for meltwater channels to erode bedrock and evacuate debris, we deduce that inner gorges are the product of ice sheets undergoing intense surface melting. The lack of postglacial river erosion in our seven gorges implicates subglacial meltwater as a key driver of valley deepening on the Baltic Shield over multiple glacial cycles.

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Section: Methodsmentioning

confidence: 99%

“…yr BP for the ice margin at Pauträsk; to this we add 875 cal. yr according to the latest correlation of the clay-varve chronology with the GRIP chronology 43 , thereby giving a deglaciation age of 10,015 cal. yr BP at Pauträsk.…”

Section: Methodsmentioning

confidence: 99%

Inner gorges cut by subglacial meltwater during Fennoscandian ice sheet decay

et al. 2014

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“…The next Baltic Sea stage, the Yoldia Sea, coincided with the onset of the Holocene epoch (Walker et al, 2009) and the associated rapid warming. In fact, the thicknesses of glacial varves in the northwestern Baltic proper and δ 18 O values in ice cores from the Greenland Ice Core Project (GRIP) display a noticeably similar pattern over a 150-year-long tran-sition period from Younger Dryas to pre-Boreal (Andrén et al, 1999. These records show a distinct increase in sedimentation rate as the ice sheet began to melt and rapidly retreat.…”

Section: Glacial-interglacial History Of the Baltic Sea Basinmentioning

confidence: 97%

“…This uniquely long varve sequence may enable a correlation to the Greenland ice core record (cf. Andrén et al, 1999Andrén et al, , 2002. The varves can possibly comprise as much as 2,000 years in one continuous sedimentary record and may have recorded, with annual resolution, the entire Younger Dryas as well as its onset and termination (Fig.…”

Section: Landsort Deep (Site M0063)mentioning

confidence: 99%

The Global Burden of Anemia

Kassebaum

2016

Hematology/Oncology Clinics of North America

585

520

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Abstract. The Integrated Ocean Drilling Program (IODP) expedition 347 cored sediments from different settings of the Baltic Sea covering the last glacial-interglacial cycle. The main aim was to study the geological development of the Baltic Sea in relation to the extreme climate variability of the region with changing ice cover and major shifts in temperature, salinity, and biological communities. Using the Greatship Manisha as a European Consortium for Ocean Research Drilling (ECORD) mission-specific platform, we recovered 1.6 km of core from nine sites of which four were additionally cored for microbiology. The sites covered the gateway to the North Sea and Atlantic Ocean, several sub-basins in the southern Baltic Sea, a deep basin in the central Baltic Sea, and a river estuary in the north.The waxing and waning of the Scandinavian ice sheet has profoundly affected the Baltic Sea sediments. During the Weichselian, progressing glaciers reshaped the submarine landscape and displaced sedimentary deposits from earlier Quaternary time. As the glaciers retreated they left a complex pattern of till, sand, and lacustrine clay, which in the basins has since been covered by a thick deposit of Holocene, organic-rich clay. Due to the stratified water column of the brackish Baltic Sea and the recurrent and widespread anoxia, the deeper basins harbor laminated sediments that provide a unique opportunity for high-resolution chronological studies.The Baltic Sea is a eutrophic intra-continental sea that is strongly impacted by terrestrial runoff and nutrient fluxes. The Holocene deposits are recorded today to be up to 50 m deep and geochemically affected by diagenetic alterations driven by organic matter degradation. Many of the cored sequences were highly supersaturated with respect to methane, which caused strong degassing upon core recovery. The depth distributions of conservative sea water ions still reflected the transition at the end of the last glaciation from fresh-water clays to Holocene brackish mud. High-resolution sampling and analyses of interstitial water chemistry revealed the intensive mineralization and zonation of the predominant biogeochemical processes. Quantification of microbial cells in the sediments yielded some of the highest cell densities yet recorded by scientific drilling.

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“…As no plant macrofossils for radiocarbon dating were found below 320 cm depth, the age model was extrapolated below this point. Sediment facies like the finely laminated sediments found in Unit II are commonly interpreted as glaciolacustrine varves in Scandinavian lakes, with couplets of light and dark layers defined as one annual sedimentation cycle reflecting the seasonally varying glaciofluvial discharge in ice-proximal settings [65,66] (see also Section 4.1). Repeated counts of the dark-light couplets in Unit II yielded 250 (±5) varves and a mean annual sedimentation of 1.8 mm.…”

Section: Age Model and Accumulation Ratesmentioning

confidence: 99%

Holocene Hydroclimate Variability in Central Scandinavia Inferred from Flood Layers in Contourite Drift Deposits in Lake Storsjön

et al. 2018

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Despite the societal importance of extreme hydroclimate events, few palaeoenvironmental studies of Scandinavian lake sediments have investigated flood occurrences. Here we present a flood history based on lithological, geochemical and mineral magnetic records of a Holocene sediment sequence collected from contourite drift deposits in Lake Storsjön (63.12 • N, 14.37 • E). After the last deglaciation, the lake began to form around 9800 cal yr BP, but glacial activity persisted in the catchment for~250 years. Element concentrations and mineral magnetic properties of the sediments indicate relatively stable sedimentation conditions during the Holocene. However, human impact in the form of expanding agriculture is evident from about 1100 cal yr BP, and intensified in the 20th century. Black layers containing iron sulphide appear irregularly throughout the sequence. The increased influx of organic matter during flood events led to decomposition and oxygen consumption, and eventually to anoxic conditions in the interstitial water preserving these layers. Elevated frequencies of black layer occurrence between 3600 and 1800 cal yr BP reflect vegetation changes in the catchment as well as large-scale climatic change. Soil erosion during snowmelt flood events increased with a tree line descent since the onset of the neoglacial period (~4000 cal yr BP). The peak in black layer occurrence coincides with a prominent solar minimum~2600 cal yr BP, which may have accentuated the observed pattern due to the prevalence of a negative NAO index, a longer snow accumulation period and consequently stronger snowmelt floods.

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Correlation of Swedish glacial varves with the Greenland (GRIP) oxygen isotope record

Cited by 85 publications

References 24 publications

Inner gorges cut by subglacial meltwater during Fennoscandian ice sheet decay

Inner gorges cut by subglacial meltwater during Fennoscandian ice sheet decay

The Global Burden of Anemia

Holocene Hydroclimate Variability in Central Scandinavia Inferred from Flood Layers in Contourite Drift Deposits in Lake Storsjön

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