Absence of West Antarctic-sourced silt at ODP Site 1096 in the Bellingshausen Sea during the last interglaciation: Support for West Antarctic ice-sheet deglaciation

Carlson, Anders E.; Beard, Brian L.; Hatfield, Robert G.; Laffin, Matthew

doi:10.1016/j.quascirev.2021.106939

Cited by 5 publications

(14 citation statements)

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“…Closer investigation of the Amundsen Sea Embayment reveals that the retreating grounding line in this area migrates inland of its present-day position shortly after 130 ka BP and progressively evacuates the interior of WAIS over the subsequent 3-4 kyr (Figure 2). This is consistent with the timing of WAIS retreat inferred from marine sediments at ODP 1096 (Carlson et al, 2021), if uncertainties associated with the bounding tephra age (130.7  1.8 ka; Hillenbrand et al, 2008) are considered. Grounded ice in the Weddell Sea embayment appears to retreat to close to its present-day extent in the millennia just before and just after 130 ka, and then stabilizes.…”

Section: Resultssupporting

confidence: 85%

“…The marine sediment core offshore the WSB at U1361A reveals a clear signal of increased iceberg rafted debris (IBRD) over the site during the LIG, which together with provenance indicators from muds eroded off the continental margin suggests either a retreat of the ice margin in the WSB, or an increase in basal erosion and sediment transport from this area (Wilson et al, 2018). A second marine core, ODP 1096 (Figure 1c), records only sediment sourced from the Antarctic Peninsula during the LIG but deposition of WAIS-derived sediment from 116 ka, suggesting perhaps that WAIS had retreated during the interglaciation and subsequently readvanced (Carlson et al, 2021).…”

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confidence: 98%

“…Ice core studies can be used with climate model simulations to gauge whether changes in ice sheet geometry may have altered climatic conditions at a core site during periods of the past, such as the LIG (Steig et al, 2015). In addition to isotopic evidence of AIS change during the LIG there also exists a horizontal ice core record from the Patriot Hills (Horseshoe Valley, West Antarctica; and marine sediment records from offshore the Wilkes Subglacial Basin (WSB, East Antarctica; Wilson et al, 2018) and the western Antarctic Peninsula (Carlson et al, 2021). The Patriot Hills blue ice record incorporates volcanic glass geochemically correlated with tephra in the Dome Fuji ice core, dated to 130.7  1.8 ka BP (AICC2012 timescale; Hillenbrand et al, 2008), abruptly truncated by a hiatus in ice accumulation until ca.…”

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confidence: 99%

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Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change

Golledge

Clark

et al. 2021

Geophysical Research Letters

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Evidence of ice sheet changes during the last time when global mean sea level (GMSL) was above present is sparse. This period, the Last Interglaciation (LIG; 129-116 ka BP) was most likely characterized by a highstand in GMSL of 6-9 m (Dutton et al., 2015;Masson-Delmotte et al., 2013) or higher (Rohling et al., 2019), but global mean surface temperatures (GMSTs) only slightly elevated (ca. +0.5-1.0°C) with respect to early industrial times (late 19th century;

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Section: Resultssupporting

confidence: 85%

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confidence: 98%

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confidence: 99%

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Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change

Golledge

Clark

et al. 2021

Geophysical Research Letters

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“…The provenance of detrital sediment components was assessed using elemental ratios that are widely varying in source rocks, and using elements that reside in minerals that are typically unaffected by chemical weathering, dissolution in the environment, biogenic uptake or authigenic mineral formation (Carlson et al., 2021; McLennan et al., 1993; Plank, 2005; Santos et al., 2007). Al 2 O 3 /TiO 2 ratios vary widely between source rock types and have been used to determine sediment provenance (Young & Nesbitt, 1998).…”

Section: Methodsmentioning

confidence: 99%

Impact of Eocene‐Oligocene Antarctic Glaciation on the Paleoceanography of the Weddell Sea

Hojnacki

Lepp

Castaldo

et al. 2022

Paleoceanog and Paleoclimatol

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The Eocene‐Oligocene Transition (EOT) at ∼34 Ma marked a climatic shift from greenhouse to icehouse conditions, toward long‐lasting lower global temperatures and a continental ice sheet in the Antarctic. We report on sedimentological and inorganic geochemical results across the EOT at Ocean Drilling Program (ODP) Site 696 in the Weddell Sea, within the Antarctic limb of the Atlantic circulation. The geochemical composition of detrital, authigenic and biogenic marine sediment components, and sortable silt proxies demonstrate the impact of ice growth on high latitude water masses. Sortable silt grain size and Zr/Rb ratios attest to a period of vigorous circulation at ∼36.2–35.8 Ma, coincident with a known warm interval in the Southern Ocean. Across the EOT, detrital provenance suggests that regional ice growth in the western Weddell Sea was stepwise, first expanding in the Antarctic Peninsula, followed by parts of West Antarctica. In conjunction with regional ice growth, high uranium enrichment factors (U EF) in sediments spanning the EOT interval indicate anoxic conditions in the sediment with evidence of carbonate dissolution. Following glacial expansion and sea‐ice formation at ∼33.6 Ma, a return to oxic conditions and carbonate preservation is observed with excess barium and phosphorous indicative of an increase in productivity, and potentially carbon export. Our results highlight the important connections between ice growth and the changing properties of high‐latitude water masses at the EOT with impacts on the global ocean circulation.

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“…Such concerns have motivated some scientists to use ice‐sheet modeling to predict AIS response to future global warming scenarios (DeConto et al., 2021; Golledge et al., 2019). It has also motivated others to examine marine sediment cores from the Southern Ocean for evidence of AIS instability during the last deglaciation (e.g., Weber et al., 2014; Weber, Golledge, et al., 2021) and the warmer than present geological past (e.g., Bertram et al., 2018; Carlson et al., 2021; Carter et al., 2017; Cook et al., 2014, 2013; Gohl et al., 2021; Hansen et al., 2015; Jakob et al., 2020; Mckay et al., 2012; Naish et al., 2009; Passchier, 2011; Patterson et al., 2014; Scherer, 1991; Starr et al., 2021; Tauxe et al., 2015; Williams et al., 2010; Wilson et al., 2018).…”

Section: Introductionmentioning

confidence: 99%

Episodes of Early Pleistocene West Antarctic Ice Sheet Retreat Recorded by Iceberg Alley Sediments

Bailey

Hemming

Reilly

et al. 2022

Paleoceanog and Paleoclimatol

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Ice loss in the Southern Hemisphere has been greatest over the past 30 years in West Antarctica. The high sensitivity of this region to climate change has motivated geologists to examine marine sedimentary records for evidence of past episodes of West Antarctic Ice Sheet (WAIS) instability. Sediments accumulating in the Scotia Sea are useful to examine for this purpose because they receive iceberg‐rafted debris (IBRD) sourced from the Pacific‐ and Atlantic‐facing sectors of West Antarctica. Here we report on the sedimentology and provenance of the oldest of three cm‐scale coarse‐grained layers recovered from this sea at International Ocean Discovery Program Site U1538. These layers are preserved in opal‐rich sediments deposited ∼1.2 Ma during a relatively warm regional climate. Our microCT‐based analysis of the layer's in‐situ fabric confirms its ice‐rafted origin. We further infer that it is the product of an intense but short‐lived episode of IBRD deposition. Based on the petrography of its sand fraction and the Phanerozoic 40Ar/39Ar ages of hornblende and mica it contains, we conclude that the IBRD it contains was likely sourced from the Weddell Sea and/or Amundsen Sea embayment(s) of West Antarctica. We attribute the high concentrations of IBRD in these layers to “dirty” icebergs calved from the WAIS following its retreat inland from its modern grounding line. These layers also sit at the top of a ∼366‐m thick Pliocene and early Pleistocene sequence that is much more dropstone‐rich than its overlying sediments. We speculate this fact may reflect that WAIS mass‐balance was highly dynamic during the ∼41‐kyr (inter)glacial world.

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Absence of West Antarctic-sourced silt at ODP Site 1096 in the Bellingshausen Sea during the last interglaciation: Support for West Antarctic ice-sheet deglaciation

Cited by 5 publications

References 99 publications

Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change

Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change

Impact of Eocene‐Oligocene Antarctic Glaciation on the Paleoceanography of the Weddell Sea

Episodes of Early Pleistocene West Antarctic Ice Sheet Retreat Recorded by Iceberg Alley Sediments

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