Pre-LGM open-water conditions south of the Drygalski Ice Tongue, Ross Sea, Antarctica

Finocchiaro, Furio; Baroni, Carlo; Colizza, Ester; Ivaldi, Roberta

doi:10.1017/s0954102007000430

Cited by 5 publications

(4 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results agree with Finocchiaro et al . (2007) and Bart & Cone (2011), who assumed that the central sector of the Ross Sea and part of its coast (south of the Drygalski Ice Tongue) enjoyed open marine conditions in the pre-LGM era (27 500–24 000 yr bp ). This assumption is based on evidence from marine sediments, terrestrial geomorphology and 14 C dating analyses on raised marine beach deposits of penguin bones.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…These results agree with Finocchiaro et al . (2007) and Bart & Cone (2011), who assumed that the centre of the Ross Sea and part of its coast (south of the Drygalski Ice Tongue) enjoyed open-marine conditions (during a pause in the advance of the West Antarctic Ice Sheet) in the pre-LGM era (27 500–24 000 bp ). An advanced glacial phase (LGM) with total coverage by the ice shelf, grounded on the basin flanks. Palaeoproductivity is null and both gravity flows and turbidity currents are present (shaded arrows in Fig.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Late Quaternary climate variability as recorded by micropalaeontological diatom data and geochemical data in the western Ross Sea, Antarctica

Tolotti¹,

Salvi²,

Salvi³

et al. 2013

Antartic science

View full text Add to dashboard Cite

Cores acquired from the Ross Sea continental shelf and continental slope during the XXX Italian Programma Nazionale di Ricerche in Antartide (PNRA) were analysed and yielded interesting micropalaeontological, biostratigraphic diatom results and palaeoceanographic implications. These multiproxy analyses enabled us to reconstruct the glacial/deglacial history of this sector of the Ross embayment over the last 40 000 years, advancing our understanding of the Last Glacial Maximum (LGM) environmental and sedimentological processes linked to the Ross Sea ice sheet/ice shelf fluctuations in a basin and continental-slope environment, and allowed us to measure some of the palaeoceanographic dynamics. The central sector of the Ross Sea and part of its coast (south of the Drygalski Ice Tongue) enjoyed open marine conditions in the pre-LGM era (27 500-24 000 years BP). The retreat of the ice sheet could have been influenced by a southward shift of a branch of the Ross gyre, which triggered early deglaciation at c. 18 600 cal BP with a significant Modified Circumpolar Deep Water inflow over the continental slope at c. 14 380 cal BP. We assume that a lack of depositional material in each core, although at different times, represents a hiatus. Other than problems in core collection, this could be due to the onset of modern oceanographic conditions, with strong gravity currents and strong High Salinity Shelf Water exportation. Moreover, we presume that improvements in biostratigraphy, study of reworked diatom taxa, and lithological and geochemical analyses will provide important constraints for the reconstruction of the LGM grounding line, ice-flow lines and ice-flow paths and an interesting tool for reconstructing palaeosub-bottom currents in this sector of the Ross embayment.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Late Quaternary climate variability as recorded by micropalaeontological diatom data and geochemical data in the western Ross Sea, Antarctica

Tolotti¹,

Salvi²,

Salvi³

et al. 2013

Antartic science

View full text Add to dashboard Cite

show abstract

“…Widespread and varied terrestrial and marine datasets from the Scott Coast (Hall et al 2004;Baroni and Hall, 2004;Jackson et al, 2018;Anderson et al, 2017;Parker, 2017;Jones et al,2015;MaKay et al, 2015;MaKay et al, 2007, Lee et al, 2017, Greenwood et al, 2018Finocchiaro et al, 2007;this study) show that grounded ice was maintained in the western Ross Sea until ~6.5 kya which is ~2.5 ky to 3.5 ky after grounded ice in the Ross Sea region had retreated to Beardmore Glacier and the Siple Coast ~700 km to ~1000 km to the south (Spector et al 2017;Kingslake et al, 2018). Grounded ice in the southwestern Ross Sea must Additionally, the Scott Coast system must have been significantly decoupled from the influence of grounded ice in the Ross Sea Region between 10.1 kya and 8.6 kya in accordance with facies transitions from marine sediment cores with a significant episode of collapse documented by outlet glacier thinning.…”

Section: Regional Significance Of Thinning Histories At Mawson and Tucker Glaciersmentioning

confidence: 99%

Outlet Glacier and Landscape Evolution of Victoria Land, Antarctica

Whitmore¹

View full text Add to dashboard Cite

<p>Terrestrial cosmogenic exposure studies are an established and rapidly evolving tool for landscapes in both polar and non-polar regions. This thesis takes a multifaceted approach to utilizing and enhancing terrestrial cosmogenic methods. The three main components of this work address method development, reconstructing surface-elevation-changes in two large Antarctic outlet glaciers, and evaluating bedrock erosion rates in Victoria Land, Antarctica. Each facet of this work is intended to enhance its respective field, as well as benefit the other sections of this thesis. Quartz purification is a necessary and critical step to producing robust and reproducible results in terrestrial cosmogenic nuclide studies. Previous quartz purification work has centred on relatively coarse sample material (1 mm-500 μm) and is effective down to 125 μm. However, sample material finer than that poses significant purification challenges and this material is usually discarded. The new purification procedure outlined in this thesis shows that very fine sand size material (125-63 μm) can be reliably cleaned for use in terrestrial cosmogenic nuclide studies. The results below show that 35% mass loss in very fine-grained quartz is sufficient to remove major elements (Al, Ti, Na, K, Fe, Mg, Ca, Mn,) and trace elements (9Be, and 10B) along with meteoric 10Be. Insufficient leaching is most detrimental to Al concentration, however errors up to 27% in exposure age and up to 29% in erosion rate are possible if meteoric 10Be is not fully removed from quartz during the HF leaching stages. Outlet glaciers have been well observed since the beginning of the satellite era, approximately 60 years ago. However, we do not currently know how these important glaciers, which drain a significant portion of the Antarctic Ice Sheet, have behaved on centennial to millennial timescales. Dating glacial erratics deposited by a thinning outlet glacier provides a window into the long-term outlet glacier and ice sheet response to climatic forcing. New results in this thesis constrain the thinning history of Mawson and Tucker glaciers over the last several thousand years. Mawson Glacier undergoes rapid thinning from at least ~6.5 kya to ~4.9 kya then transitions to slower thinning until ~1 kya, with a minimum of 250 m of ice-surface-lowering. While Tucker Glacier ~450 km north undergoes gradual thinning from ~19 kya to ~5 kya with ~300 m of ice-surface-lowering. The results of this work show that either the Tucker Glacier was not significantly affected by the Ross Ice Shelf grounding line, or that Antarctic mountain glaciers respond differently to the outlet glaciers connected to the Easty Antarctic Ice Sheet. The style, rate, magnitude, and duration of thinning is unique to each outlet glacier, even with similar climate forcing. The results of this work shed light on the style and duration of outlet glacier thinning and retreat that is possible following a climate perturbation. Antarctica’s average bedrock erosion rate is consistently lower than 4.5 m/Myr, the lowest bedrock erosion rates for any region on Earth. Therefore, many cosmogenic dating studies assume zero erosion when calculating exposure ages. However, previous erosion rate work in Antarctica is biased to arid high-elevation inland sites (~60% of work) and the hyperarid ice-free McMurdo Dry Valleys (~40% of work). These studies do not capture the effects of coastal maritime climates, where many outlet glacier studies are conducted, on the rate of bedrock erosion. New results presented in this thesis show that the Northern Victoria Land coast has the highest known erosion rate in Antarctica. Two sample sites were selected, one coastal and one in the interior. The coastal bedrock erosion rates are 8.86±0.78 m/Myr and 7.15±0.6 m/Myr while the interior bedrock erosion rates are 1.07±0.08 m/Myr and 0.42±0.03 m/Myr. The coastal erosion rates are average for non-polar cold climates while the inland sites are below average for polar erosion rates. The results suggest a strong gradient in the rate of erosion is present from the Antarctic coastline inland. If exposure ages are not calculated with an appropriate erosion rate the apparent age may under-estimate the actual age by as much as 12%, which is thousands of years for Holocene thinning histories like those found in this thesis.</p>

show abstract

Antarctic palaeo-ice streams

Livingstone

Cofaigh

Stokes

et al. 2012

Earth-Science Reviews

180

183

View full text Add to dashboard Cite

We review the geomorphological, sedimentological and chronological evidence for palaeo- palaeo-ice streams to be classified into discrete retreat styles and the controls on grounding-21 line retreat to be investigated. Such analysis highlights the important impact of internal 22 factors on ice stream dynamics, such as bed characteristics and slope, and drainage basin size. 23Whilst grounding-line retreat may be triggered, and to some extent paced, by external 24 (atmospheric and oceanic) forcing, the individual characteristics of each ice stream will 25 modulate the precise timing and rate of retreat through time. ). The ability to directly observe the beds of palaeo-ice streams has also allowed 65 scientists to glean important spatial and temporal information on the processes that occurred 66 at the ice-bed interface and on the evolution of palaeo-ice streams throughout their glacial 67 history. 68Over the last two decades, there has been a burgeoning interest in marine palaeo-ice streams, and the timing and rate of deglaciation (e.g. Wellner et al. 2001;Canals et al., 2000; Lowe & 73 Anderson, 2002;Ó Cofaigh et al. 2002;Graham et al. 2009 115The first glacimarine investigations in Antarctica utilised echosounder data, till petrographic 116 studies and seismic data to reconstruct the expansion of grounded ice across the continental 117 shelf during the last glaciation (e.g. Kellogg et al. 1979; Anderson et al. 1980; Orheim & 118 Elverhøi, 1981;Domack, 1982;Haase, 1986;Kennedy & Anderson, 1989 Pudsey et al. 1994;Larter & Vanneste, 1995;O'Brien et al. 1999;Shipp et al. 1999; Canals 123 et al. 2000 Canals 123 et al. , 2002 Canals 123 et al. , 2003Anderson & Shipp, 2001;Wellner et al. 2001;Ó Cofaigh et al. 2002 Ó Cofaigh et al. , 124 2003 Ó Cofaigh et al. , 2005a Lowe & Anderson, 2003; Dowdeswell et al. 2004a,b;Evans et al. 2004Evans et al. , 2005 recently been demonstrated (Padman et al., 2010). 132In O'Brien et al. 1999O'Brien et al. , 2007 Table 2 provides a synthesis of the key physiographic data of each palaeo-ice stream in our 215 new inventory (see Fig. 1 and (ten Brink & Schneider, 1995). 228It is also apparent from 248The majority of the Antarctic palaeo-ice streams retreated across reverse slopes ( 2010) is suggested to relate to the much smaller size of its drainage basin (10,000-100,000 269 km 2 ), which is likely to have been much more sensitive to external and internal forcing. East Antarctic Peninsula, has also been associated with a change in basal processes (from 327 9 basal sliding to deformation) and an increase in ice velocity (Reinardy et al. 2011b The geometry of the basal reflector underlying the acoustically transparent unit ranges from 363 smooth and flat to irregular and undulating ( shelf (Pudsey et al. 1994Licht et al. 1996Licht et al. , 1998Licht et al. , 1999 between this bedrock and unconsolidated sediment further out on the shelf (Fig. 4c and Table 493 3) (Anderson et al. 2001; Camerlenghi et al. 2001;Wellner et al. 2001Wellner et al. , 2006...

show abstract

Pre-LGM open-water conditions south of the Drygalski Ice Tongue, Ross Sea, Antarctica

Cited by 5 publications

References 26 publications

Late Quaternary climate variability as recorded by micropalaeontological diatom data and geochemical data in the western Ross Sea, Antarctica

Late Quaternary climate variability as recorded by micropalaeontological diatom data and geochemical data in the western Ross Sea, Antarctica

Outlet Glacier and Landscape Evolution of Victoria Land, Antarctica

Antarctic palaeo-ice streams

Contact Info

Product

Resources

About