Destructive and non-destructive density determination: method comparison and evaluation from the Laguna Potrok Aike sedimentary record

Fortin, David; Francus, Pierre; Gebhardt, Catalina; Hahn, Annette; Kliem, P.; Lisé-Pronovost, Agathe; Roychowdhury, Rajarshi; Labrie, Jacques; St‐Onge, Guillaume

doi:10.1016/j.quascirev.2012.08.024

Cited by 57 publications

(45 citation statements)

References 17 publications

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“…The resulting images are displayed in a greyscale with the darker grey representing a lower X-ray attenuation (Boespflug et al 1995;Guyard et al 2007a). Greyscale values are expressed as CT numbers, which are complex units related to the mineralogy, organic matter content, grain size, and bulk density (e.g., Fortin et al 2013).…”

Section: Methodsmentioning

confidence: 99%

Microfacies and microstructures of subglacial and deglacial sediments from the Pingualuit Crater Lake (Ungava Peninsula, Canada)

et al. 2014

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International audienceAbstract: The Pingualuit Crater (Ungava Peninsula, Canada) hosts a freshwater basin in which a subglacial lake subsisted under the Laurentide Ice Sheet during the last glacial period. Microfacies and microstructures of a 9mlong sediment core are presented to discuss the depositional environment of deformed glacigenic and postglacial sequences deposited in the deep basin of the lake. Five distinct lithofacies are characterized. The range of glacial microstructures observed in the lower facies (Facies IV) reveals that high stress level occurred outside the crater during the formation of this diamicton released by the ablation of debris-rich basal glacier ice in an ice contact subglacial–proglacial lacustrine environment. The overlying subaqueous and glacigenic sediment gravity flow (Facies IIIb) is associated with a temporary absence of ice cover over the coring site, and likely results from the efflux plume and the associated suspension sedimentation produced during the retreat of the ice margin. Then, the finely laminated (<1–2 mm) and normally graded meltout silts (Facies IIIa) containing dropstones and load cast featuressuggest underflows in an unstable ice marginal lacustrine environment hydrologically separated from the retreating glacier but containing floating glacial ice blocks. Microstructures within occasional diamictic layers indicate sudden meltout deposits from these drifting ice blocks. The above finer-grained sediments (Facies Ib) lack typical glacial microstructures, marking the onset of postglacial organic sedimentation. These postglacial sediments are affected by post-depositional deformations due to an overlying rotational slide (Facies II) that may have perturbed the associated environmental record

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Section: Methodsmentioning

confidence: 99%

Microfacies and microstructures of subglacial and deglacial sediments from the Pingualuit Crater Lake (Ungava Peninsula, Canada)

et al. 2014

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“…Incident X-rays are attenuated by a wide range of phenomena, with grey levels acting as a measure of attenuation. Fortin et al (2013) show that sediment density may be calculated using radiographic data for each pixel. The latter is influenced by various factors such as sediment porosity, water content, composition (OM, biogenic silica, mineralogy), and grain size (St-Onge et al, 2007).…”

Section: Carbon Stock Calculationmentioning

confidence: 99%

Geomorphological controls on fluvial carbon storage in headwater peatlands

Alderson

Evans

Rothwell

et al. 2019

Earth Surf Processes Landf

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Geomorphological controls and catchment sediment characteristics control the formation of floodplains and affect their capacity to sequester carbon. Organic carbon stored in floodplains is typically a product of pedogenic development between periods of mineral sediment deposition. However, in organically‐dominated upland catchments with a high sediment load, eroded particulate organics may also be fluvially deposited with potential for storage and/or oxidation. Understanding the redistribution of terrestrial carbon laterally, beyond the bounds of river channels is important, especially in eroding peatland systems where fluvial particulate organic carbon exports are often assumed to be oxidised. Floodplains have the potential to be both carbon cycling hotspots and areas of sequestration. Understanding of the interaction of carbon cycling and the sediment cascade through floodplain systems is limited. This paper examines the formation of highly organic floodplains downstream of heavily eroded peatlands in the Peak District, UK. Reconstruction of the history of the floodplains suggests that they have formed in response to periods of erosion of organic soils upstream. We present a novel approach to calculating a carbon stock within a floodplain, using XRF and radiograph data recorded during Itrax core scanning of sediment cores. This carbon stock is extrapolated to the catchment scale, to assess the importance of these floodplains in the storage and cycling of organic carbon in this area. The carbon stock estimate for the floodplains across the contributing catchments is between 3482‐13460 tonnes, equating on an annualised basis to 0.8‐4.5% of the modern‐day POC flux. Radiocarbon analyses of bulk organic matter in floodplain sediments revealed that a substantial proportion of organic carbon was associated with re‐deposited peat and has been used as a tool for organic matter source determination. The average age of these samples (3010 years BP) is substantially older than Infrared Stimulated Luminesence dating which demonstrated that the floodplains formed between 430 and 1060 years ago. Our data suggest that floodplains are an integral part of eroding peatland systems, acting as both significant stores of aged and eroded organic carbon and as hotspots of carbon turnover. © 2019 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.

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“…The density of the sediment is partly dependent on the carbonate content, but carbonate content influence on the density depends also on the density of the other components of the sediment (Reghellin et al, 2013), so that it was not possible to accurately infer density variations from the changes in the 15 carbonate content alone. Attempts to estimate density from other sedimentary variables based on existing calibrations (Dadey et al, 1992;Weber et al, 1997;Fortin et al, 2013) were not successful. Unassessed changes of sediment density are therefore likely to introduce uncertainty for many records, although the largest and most systematic change is likely to be the long-term increasing trend caused by compaction, which is addressed by the long-term trend correction.…”

Section: Bmentioning

confidence: 99%

Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle

Cartapanis¹,

Galbraith²,

Bianchi³

et al. 2018

Preprint

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Abstract. Although long assumed that the glacial-interglacial cycles of atmospheric CO 2 occurred despite a constant 'active' carbon inventory, there are signs that the geological CO 2 supply rates varied. However, changes of the carbon inventory cannot be assessed without constraining the removal rates from the system, which mainly occurs in marine sediments. Here, 15we present the first global reconstruction of carbon and alkalinity burial in deep-sea sediments over the last glacial cycle.Although subject to large uncertainties, the reconstruction provides a first order constraint on changes in carbon and alkalinity inventories over the last glacial cycle. The results suggest that reduced burial of carbonate in the Atlantic Ocean was not entirely compensated by the increased burial in the Pacific basin during the last glacial period. The burial-driven inventory variations are likely to have significantly altered the δ 13 C of the ocean-atmosphere carbon, as well as the DIC and 20 alkalinity budget, confirming that the active carbon inventory was a dynamic, interactive component of the glacial cycles.Clim. Past Discuss., https://doi

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Destructive and non-destructive density determination: method comparison and evaluation from the Laguna Potrok Aike sedimentary record

Cited by 57 publications

References 17 publications

Microfacies and microstructures of subglacial and deglacial sediments from the Pingualuit Crater Lake (Ungava Peninsula, Canada)

Microfacies and microstructures of subglacial and deglacial sediments from the Pingualuit Crater Lake (Ungava Peninsula, Canada)

Geomorphological controls on fluvial carbon storage in headwater peatlands

Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle

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