Magneto-biostratigraphic age models for Pleistocene sedimentary records from the Ross Sea

Ohneiser, Christian; Yoo, Kyu‐Cheul; Albot, Olga; Cortese, Giuseppe; Riesselman, C. R.; Lee, Jae Il; McKay, Robert; Bollen, Michael; Lee, Min Kyung; Moon, Heung Soo; Kim, Sunghan; Beltran, Catherine; Levy, R. H.; Wilson, Gary

doi:10.1016/j.gloplacha.2019.02.013

Cited by 14 publications

(9 citation statements)

References 59 publications

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“…While the units consisting of low MS, low NGR, and high biogenic character inferred from high Ba/Al, high silt and high diatom abundance correspond to interglacial periods MIS 1, 5, 7, and 9. The variations in these properties between glacial and interglacial phases have been previously recognized in other records spanning the middle Pleistocene to Holocene in various of the Antarctic slope sectors including Wilkes Land (Escutia et al, 2003, 2011; Jimenez‐Espejo et al, 2020; Presti et al, 2011; Wilson et al, 2018), Dronning Maud Land (Bonn et al, 1998), the Ross Sea (Kim et al, 2020; Ohneiser et al, 2019), Prydz Bay (Passchier et al, 2003; Theissen et al, 2003), and the Antarctic Peninsula (Grobe & Mackensen, 1992; Hillenbrand et al, 2009; Lucchi et al, 2002; Pudsey, 2000).…”

Section: Resultsmentioning

confidence: 61%

Controls Since the mid‐Pleistocene Transition on Sedimentation and Primary Productivity Downslope of Totten Glacier, East Antarctica

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Duffy

Opdyke

et al. 2020

Paleoceanog and Paleoclimatol

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The rapidly thinning Totten Glacier on the Sabrina Coast, East Antarctica, is the primary drainage outlet for ice within the Aurora Subglacial Basin, which could destabilize under the current atmospheric warming trend. There is growing need for direct geological evidence from the Sabrina Coast to frame late twentieth century Totten melting in the context of past warm climate analogs. Addressing this need, sediment archives were recovered from two sites on the Sabrina Coast slope and rise that record changes in terrigenous sedimentation and primary productivity in the region over glacial cycles since the mid‐Pleistocene transition (MPT). This research presents physical properties, grain size, diatom abundance and assemblages, and geochemical analysis from the two sites to determine how the processes that control sedimentation change between glacial and interglacial phases. The stratigraphic sequences in both cores record cyclic variations in physical properties and diatom abundances, which radiocarbon and biostratigraphic chronologies reveal as 100 Kyr glacial‐interglacial cyclicity. During glacials, terrigenous sediment deposition is enhanced by advanced grounded ice on the shelf, while primary productivity is restricted due to permanent summer sea ice extending past the continental slope. During interglacials, pelagic sedimentation suggests high surface productivity associated with contractions of regional sea ice cover. Comparison with post‐MPT slope records from Wilkes Land and the Amundsen Sea shows that this pattern is consistent in slope sediments around the margin. The higher‐amplitude variations in Antarctic ice volume and sea ice extent post‐MPT ensure that these signals are pervasive around the Antarctic margin.

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Section: Resultsmentioning

confidence: 61%

Controls Since the mid‐Pleistocene Transition on Sedimentation and Primary Productivity Downslope of Totten Glacier, East Antarctica

Holder

Duffy

Opdyke

et al. 2020

Paleoceanog and Paleoclimatol

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“…To conduct the comparisons of the three IRD abundance methods, two sediment gravity cores (11 cm diameter) RS15‐LC42 and RS15‐LC48 were obtained by the Korea Polar Research Institute (KOPRI) Icebreaker R/V Araon in 2014/15 (Figure 1) from contourite drifts in 2,084 and 3,167 m water depth, respectively, in the Western Ross Sea. The cores were split, and visual core descriptions were undertaken aided by x‐radiograph imaging (Jung et al., 2019; Ohneiser et al., 2019) and verified by quantitative grain size analysis using LPSA. For x‐radiograph analysis, a 1‐cm‐thick, 8 × 30‐cm slab was removed from the center of each split core section, placed within plastic plates and x‐rayed.…”

Section: Methodsmentioning

confidence: 99%

“…Figure 6. Lithological columns (afterOhneiser et al, 2019), biogenic opal %, coarse fraction grain size analysis, and LPSA grain size measurements from cores RS15-LC42 (top row) and RS15-LC48 (bottom row). Grain size analysis shows number of clasts (>2 mm) counted on x-radiographs (x-ray count), percentages of the terrigenous fraction 250 μm-2 mm obtained by sieving, and volume percentages of the biogenic-free fraction 125 μm-2 mm as determined by LPSA.…”

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confidence: 99%

A Comparison of Methods for Identifying and Quantifying Ice Rafted Debris on the Antarctic Margin

McKay

Albot

Dunbar

et al. 2022

Paleoceanog and Paleoclimatol

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Quantification of ice rafted debris (IRD) abundances in deep‐sea records is often used as a key proxy for identifying links between ice sheet instability and the oceanic overturning circulation. There currently exist multiple methods to determine IRD content in deep‐sea sediment cores. The preference for a given method is often determined by the accessibility to core material and destructive nature of some methods. While many studies have discussed the caveats between linking IRD to ice sheet dynamics, the uncertainties relating to the methodological approaches are often not considered in the interpretation or comparisons between different IRD datasets, particularly in the Antarctic. To address this, we compare three independent methodologies of obtaining IRD abundances and also discuss how different approaches will affect determinations of mass accumulation rates (MARs). The three methodologies we examine include: counting clasts >2 mm in x‐radiographs; the sieved weight percentage of the medium‐to‐coarse sand fraction (250 μm–2 mm); and volumetric estimates of the >125 μm sand fraction using laser diffraction particle size analysis. The x‐radiograph and sieve methods produced comparable results, while the laser particle size analysis, although showing comparable long‐term signals at most locations, in general has lower correlation to the other two methods and therefore a higher potential to obtain a noisy signal. We discuss the caveats associated with all methods, and emphasize that a combination of multiple methods should ideally be employed when assessing if a core is suitable for IRD study, and if sand or gravel fractions are accurately reflecting contents of IRD.

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“…In particular, varved couplets of diatomaceous lamina can form in regions of extremely high primary productivity in the calving bays of the Antarctic ice sheet during the deglaciation (e.g., Leventer et al, 2006). Ohneiser et al (2019) reported the glaciomarine laminated muds in the Central Basin at the upper continental slope of the northwestern Ross Sea. In this study, we reveal, based on the macro-to microscopic observations of sediment texture, componentry, and structure, that the type of these laminated muds is different and previously undocumented.…”

Section: Introductionmentioning

confidence: 99%

Pleistocene glaciomarine laminated muds in the Central Basin of the northwestern Ross Sea and their palaeoceanographic records

Khim,

Sohn,

Lee

et al. 2023

Terra Nova

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Glaciomarine laminated muds around the Antarctic continental margin are important in the marine geological record related to ice sheet dynamics. Microscopic observation and backscattered electron imagery of Pleistocene laminated muds in the Central Basin (Ross Sea) reveal that the light laminae comprise terrigenous angular to subangular silt‐sized particles, scattered diatom fragments, and eroded sand‐sized lumps of fossil‐bearing mud. In contrast, the dark laminae are clayey and biogenic with very tiny pieces of fossils. These laminated muds are interpreted to have been deposited by subglacial meltwater plumes underneath the advancing glaciers that torn off the earlier‐deposited and semi‐consolidated diatom‐rich sediments. Thus, most biogenic components of these laminated muds were recycled from older deposits, indicating that they are not related to enhanced biological production during the mud deposition. Our study suggests that the recycling of biogenic particles should be considered when interpreting the palaeoclimatic and palaeoceanographic implications of Antarctic environmental system.

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Magneto-biostratigraphic age models for Pleistocene sedimentary records from the Ross Sea

Cited by 14 publications

References 59 publications

Controls Since the mid‐Pleistocene Transition on Sedimentation and Primary Productivity Downslope of Totten Glacier, East Antarctica

Controls Since the mid‐Pleistocene Transition on Sedimentation and Primary Productivity Downslope of Totten Glacier, East Antarctica

A Comparison of Methods for Identifying and Quantifying Ice Rafted Debris on the Antarctic Margin

Pleistocene glaciomarine laminated muds in the Central Basin of the northwestern Ross Sea and their palaeoceanographic records

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