Sea-ice ploughmarks in the eastern Laptev Sea, East Siberian Arctic shelf

Ananyev, R. A.; Dmitrevskiy, N. N.; Lobkovsky, L. I.; Nikiforov, S. L.; Roslyakov, A. G.; Semiletov, I. P.

doi:10.1144/m46.109

Cited by 10 publications

(13 citation statements)

References 4 publications

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“…An actual sediment transport process giving rise to such a putative total halt in the sedimentation rate is rather elusive and unlikely. Since the whole ESAS is a very shallow shelf where sea ice is formed (Conlan et al, 1998;Jakobsson, 2002), another explanation for an age gap is ice scouring as observed in the Laptev Sea (Ananyev et al, 2016), especially at ∼ 8500 cal yrs BP when the sea level was around 18 m lower (Lambeck et al, 2014) than today and the water depth at the coring site was around 32 m. At the time of the second age gap (∼ 1700 cal yrs BP), the water depth at the coring site was approximately 52 m. An ice scouring event could have formed a gouge at the sea bottom that was later refilled with sediment (Barnes et al, 1984). Table 1) and 210 Pb (base of a multicore collected at the same location; see Table S2 in the Supplement).…”

Section: Age Chronology Of the Corementioning

confidence: 99%

Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

et al. 2017

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Abstract. Thawing of permafrost carbon (PF-C) due to climate warming can remobilise considerable amounts of terrestrial carbon from its long-term storage to the marine environment. PF-C can be then be buried in sediments or remineralised to CO 2 with implications for the carbon-climate feedback. Studying historical sediment records during past natural climate changes can help us to understand the response of permafrost to current climate warming. In this study, two sediment cores collected from the East Siberian Sea were used to study terrestrial organic carbon sources, composition and degradation during the past ∼ 9500 cal yrs BP. CuO-derived lignin and cutin products (i.e., compounds solely biosynthesised in terrestrial plants) combined with δ 13 C suggest that there was a higher input of terrestrial organic carbon to the East Siberian Sea between ∼ 9500 and 8200 cal yrs BP than in all later periods. This high input was likely caused by marine transgression and permafrost destabilisation in the early Holocene climatic optimum. Based on source apportionment modelling using dual-carbon isotope ( 14 C, δ 13 C) data, coastal erosion releasing old Pleistocene permafrost carbon was identified as a significant source of organic matter translocated to the East Siberian Sea during the Holocene.

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Section: Age Chronology Of the Corementioning

confidence: 99%

Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

et al. 2017

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“…Large numbers of sea-ice-derived ploughmarks are, therefore, found only on shallow continental shelves such as those of the Beaufort and Laptev seas (e.g. Héquette et al 1995;Ananyev et al 2016) where water depths are only a few tens of metres over very large areas.…”

Section: Glacimarine Landformsmentioning

confidence: 99%

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Dowdeswell

Canals

Jakobsson

et al. 2016

Memoirs

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Glacimarine processes affect about 20% of the global ocean today, and this area expanded considerably under cyclical full-glacial conditions during the Quaternary (Fig. 1) . Many of the submarine landforms produced at the base and margin of past ice sheets remain well preserved on the seafloor in fjords and on high-latitude continental shelves after the retreat of the ice that produced them. These glacial landforms, protected from subaerial erosion and beneath wave-base and tidal currents in water that is often hundreds of metres deep, are gradually buried by both hemipelagic and glacimarine sedimentation; they may be preserved over long periods in the geological record if palaeocontinental shelves are not reworked by subsequent glacier advances or bottom currents ). This means that, first, submarine glacial landforms can be observed at or close to the modern seafloor after retreat of the last great ice sheets from their most recent Quaternary maximum about 18-20 000 years ago using swath-bathymetric mapping systems and, secondly, buried glacial landforms may also be identified and examined within glacial-sedimentary sequences from Quaternary and earlier ice ages using seismic-reflection methods.The development of multibeam echo sounding over the past two decades, coupled with high-accuracy GPS positioning, has allowed morphological mapping of the seafloor at an unprecedented level of detail. In this paper, the variety of submarine glacial landforms observed in modern, Quaternary and more ancient sediments is described. Landforms produced subglacially, those formed at and beyond marine ice-sheet margins, together with the slope processes and bottom currents likely to result in their reworking, are considered along with the sediment volumes of these landforms and the time they take to develop. This is followed by discussion of the significance of submarine glacial landforms and landform-assemblages for reconstruction of the form and flow of past ice sheets, including the former extent and flow direction of ice sheets, whether they are flowing fast as ice streams or slowly in inter-ice stream areas, the nature and rate of ice-sheet deglaciation, conditions at past ice-sheet beds, and inferences on the characteristics of the basal hydrological system and past climatic conditions.

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“…Secondly, geophysical observations have repeatedly detected the ice scours both in the coastal zone, and on the outer part of ESAS [58][59][60][61]. Age of these scours is still under debate [62,63]. Jakobsson and coauthors provide evidence of a kilometer-thick ice shelf covering the entire central Arctic Ocean and extending up to present-day New Siberian Islands during the glacial maximum (Marine Isotope Stage 6, 140 ka BP) [62].…”

Section: Grain Size Distribution Along the Studied Profilementioning

confidence: 99%

Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators

Gershelis

Гринько

Oberemok

et al. 2020

Water

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Global warming in high latitudes causes destabilization of vulnerable permafrost deposits followed by massive thaw-release of organic carbon. Permafrost-derived carbon may be buried in the nearshore sediments, transported towards the deeper basins or degraded into the greenhouse gases, potentially initiating a positive feedback to climate change. In the present study, we aim to identify the sources, distribution and degradation state of organic matter (OM) stored in the surface sediments of the Laptev Sea (LS), which receives a large input of terrestrial carbon from both Lena River discharge and intense coastal erosion. We applied a suite of geochemical indicators including the Rock Eval parameters, traditionally used for the matured OM characterization, and terrestrial lipid biomarkers. In addition, we analyzed a comprehensive grain size data in order to assess hydrodynamic sedimentation regime across the LS shelf. Rock-Eval (RE) data characterize LS sedimentary OM with generally low hydrogen index (100–200 mg HC/g TOC) and oxygen index (200 and 300 CO2/g TOC) both increasing off to the continental slope. According to Tpeak values, there is a clear regional distinction between two groups (369–401 °C for the inner and mid shelf; 451–464 °C for the outer shelf). We suggest that permafrost-derived OM is traced across the shallow and mid depths with high Tpeak and slightly elevated HI values if compared to other Arctic continental margins. Molecular-based degradation indicators show a trend to more degraded terrestrial OC with increasing distance from the coast corroborating with RE results. However, we observed much less variation of the degradation markers down to the deeper sampling horizons, which supports the notion that the most active OM degradation in LS land-shelf system takes part during the cross-shelf transport, not while getting buried deeper.

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Sea-ice ploughmarks in the eastern Laptev Sea, East Siberian Arctic shelf

Cited by 10 publications

References 4 publications

Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators

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