Multi-proxy analysis of Late Quaternary ODYSSEA Contourite Depositional System (Ross Sea, Antarctica) and the depositional record of contour current and cold, dense waters

2020 ◽  
Author(s):  
Michele Rebesco ◽  
Renata Giulia Lucchi ◽  
Andrea Caburlotto ◽  
Stefano Miserocchi ◽  
Leonardo Langone ◽  
...  
Keyword(s):  
Ross Sea ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Current Strength ◽  
Global Ocean ◽  
General Assembly ◽  
Geophysical Research ◽  
Dense Water ◽  
Depositional System ◽  
Ice Sheet Dynamics

<p>The Ross Ice Shelf is the Antarctic region that over the last deglaciation experienced the greatest change in areal ice cover. Today, cold, dense and saline water masses (brines) produced in the Ross Sea polynya, flow from the shelf to the deep ocean providing a significant contribution to the propelling of the global ocean circulation regulating the climate. In particular, the Hillary Canyon in the Eastern Ross Sea is the main conduit through which brines descend the slope to reach the deeper ocean and is thus one of the greatest regions of cold, dense water export in the world.</p><p>A Contourite Depositional System (the ODYSSEA CDS) on the western flank of the Hillary Canyon is inferred to have been generated through several hundred-thousand years by along-slope, contour currents that transported and accumulated the sediments brought down the Hillary Canyon by means of brines. A multi-proxy investigation was conducted on the shallowest part of the ODYSSEA CDS depositional sequences, which we expect to contain i) the record of the brine formation, ii) the indication on contour current strength through time, and iii) their interplay and modulation associated to climate change.</p><p>Six gravity cores, collected in both the proximal and distal area of the ODYSSEA CDS, were studied through multi-proxy analyses including sediment physical properties (texture, structures, water content, wet bulk density), compositional characteristics (XRF, geochemistry and detrital apatite, zircon, and rutile U-Pb on ice-rafted debris) (Lucchi et al., 2019; Neofitu et al., 2020) and microfossil content (planktonic and benthic foraminifera, calcareous nannofossils and diatoms). An age model has been reconstructed combining palaeomagnetic record, biostratigraphic content, tephrochronology and AMS radiocarbon dating on planktonic foraminifera tests.</p><p>Inferred variations in dense water formation, contour current strength and <strong>ice sheet dynamics </strong>are discussed in the light of our data interpretation.</p><p> </p><p>Lucchi, R.G., Caburlotto, A., Miserocchi, S., Liu, Y., Morigi, C., Persico, D., Villa, G., Langone, L., Colizza, E., Macrì, P., Sagnotti, L., Conte, R., Rebesco, M., 2019. The depositional record of the Odyssea drift (Ross Sea, Antarctica). Geophysical Research Abstracts, Vol. 21, EGU2019-10409-1, 2019. EGU General Assembly, Vienna (Austria), 7–12, April, 2019 (POSTER).</p><p>Neofitu, R., Mark, C., Rebesco, M., Lucchi, R.G., Douss, N., Morigi, C., Kelley, S., Daly, J.S., 2020. Tracking Late Quaternary ice sheet dynamics by multi-proxy detrital mineral U-Pb analysis: A case study from the Odyssea contourite, Ross Sea, Antarctica. Geophysical Research Abstracts. EGU General Assembly, Vienna (Austria), 3–8, May, 2020 (POSTER for session CL1.11).</p>

Tracking Late Quaternary ice sheet dynamics by multi-proxy detrital mineral U-Pb analysis: A case study from the Odyssea contourite, Ross Sea, Antarctica

2020 ◽  
Author(s):  
Roland Neofitu ◽  
Chris Mark ◽  
Michele Rebesco ◽  
Renata Giulia Lucchi ◽  
Nessim Douss ◽  
...  
Keyword(s):  
Ross Sea ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Source Area ◽  
Coarse Sand ◽  
Turbidity Currents ◽  
Provenance Analysis ◽  
Geophysical Research ◽  
Antarctic Ice Sheet ◽  
Volcanic Material

<p>Late Quaternary Antarctic ice-sheet instability is recorded by ice-rafted debris (IRD) in mid- to high-latitude marine sediment, especially during marine isotope stages (MIS) 2-3, but drivers of this instability remain enigmatic (Labeyrie et al., 1986). A key step in resolving this puzzle is to determine the location of iceberg calving sites, thus highlighting ice sheet sectors exhibiting repeated instability. Single-grain U-Pb provenance analysis applied to clastic IRD provides a suitable high-resolution tool for this task, and also permits discrimination of continental IRD from volcanic material. The application of multiple proxies (apatite, rutile, and zircon) is critical in order to reduce source area fertility biases: for example, the near exclusive occurrence of zircon in felsic-intermediate igneous rocks (e.g., Hietpas et al., 2010).</p><p>Here, we present detrital apatite, zircon, and rutile U-Pb data from samples taken from a gravity core from the Odyssea contourite drift system, located on the margin of the Ross Sea (Rebesco et al., 2018) and deposited during MIS2-3. Contourites are marine clastic sediment deposits forming by along-slope, bottom currents reworking of fine-grained (clay-silt) sediments delivered by down-slope sedimentary processes (e.g. meltwaters, turbidity currents, debris flows). Crucially, contourite targetting eliminates the challenge of distinguishing IRD from coarse (sand-gravel) turbidite material in basin deposits, as ice-sheet instability is also associated with turbidite production at glaciated shelf margins (e.g., Bart et al., 1999).</p><p>We couple our analysis with the multi-proxy sediment analyses previously performed by Lucchi et al. (2019). We consider the implications of our data for the advance and retreat of the Antarctic Ice Sheet during MIS 2-3, and discuss the further applicability of our multi-proxy approach around Antarctica.</p><p>Bart, P.J, et al., 1999, Journal of Sedimentary Research, v. 69, p. 1276–1289, doi:10.2110/jsr.69.1276.</p><p>Hietpas, J, et al., 2010, Geology, v. 38, p. 167–170, doi:10.1130/G30265.1.</p><p>Lucchi, R.G, et al., 2019. EGU General Assembly 2019, Vienna April 7<sup>th</sup>–12<sup>th</sup>, Geophysical Research Abstracts Vol. 21, EGU2019-10409-1</p><p>Rebesco, M, et al., 2018, preliminary results, in POLAR 2018 SCAR/IASC Open Science Conference, v. GG2 Arctic, p. 14133.</p><p>Labeyrie, L, et al., 1986, Nature, v. 322, p. 701–706.</p>

scholarly journals Late Quaternary paleoenvironment of the Ross Sea continental shelf, Antarctica

1998 ◽  
Vol 27 ◽  
pp. 275-280 ◽  
Author(s):  
Akira Nishimura ◽  
Toru Nakasone ◽  
Chikara Hiramatsu ◽  
Manabu Tanahashi
Keyword(s):  
Organic Carbon ◽  
Marine Environment ◽  
Environmental Changes ◽  
Ross Sea ◽  
Late Quaternary ◽  
Sedimentary Environment ◽  
Sediment Cores ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Accelerator Mass Spectrometer

Based on sedimenlological and micropaleontological work on three sediment cores collected at about 167° Ε in the western Ross Sea, Antarctica, and accelerator mass spectrometer l4C ages of organic carbon, we have reconstructed environmental changes in the area during the late Quaternary. Since 38 ka BP at latest, this area was a marine environment with low productivity. A grounded ice sheet advanced and loaded the sediments before about 30-25 ka BP. After 25 ka BP, the southernmost site (76°46'S) was covered by floating ice (shelf ice), preventing deposition of coarse terrigenous materials and maintaining a supply of diatom tests and organic carbon until 20 ka BP. The northernmost site (74°33'S) was in a marine environment with a moderate productivity influenced by shelf ice/ice sheet after about 20 ka BP. Since about 10 ka BP, a sedimentary environment similar to the present-day one has prevailed over this area.

scholarly journals Monsoonal Forcing of European Ice‐Sheet Dynamics During the Late Quaternary

2018 ◽  
Vol 45 (14) ◽  
pp. 7066-7074 ◽  
Author(s):  
Stefanie Kaboth‐Bahr ◽  
André Bahr ◽  
Christian Zeeden ◽  
Samuel Toucanne ◽  
Frédérique Eynaud ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Ice Sheet Dynamics

Past ice flow in Wahlenbergfjorden and its implications for late Quaternary ice sheet dynamics in northeastern Svalbard

2017 ◽  
Vol 163 ◽  
pp. 162-179 ◽  
Author(s):  
Anne E. Flink ◽  
Riko Noormets ◽  
Oscar Fransner ◽  
Kelly A. Hogan ◽  
Matthew ÓRegan ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Ice Flow ◽  
Ice Sheet Dynamics

Surface exposure dating of the Pierre Sublobe of the James Lobe, Laurentide Ice Sheet

2020 ◽  
Vol 97 ◽  
pp. 88-98
Author(s):  
Stephanie L. Heath ◽  
Thomas V. Lowell ◽  
Brenda L. Hall
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Age Dating ◽  
Laurentide Ice Sheet ◽  
Des Moines Lobe ◽  
Exposure Dating ◽  
Des Moines ◽  
Contrast Exposure ◽  
Ice Sheet Dynamics ◽  
Exposure Ages

AbstractThe Laurentide Ice Sheet of the last glacial period terminated in several lobes along its southern margin. The timing of maximum extent may have varied among the terminal lobes owing to internal ice sheet dynamics and spatially variable external controls. Some terminal ice lobes, such as the westernmost James Lobe, remain poorly dated. To determine the timing of maximum ice extent in this key location, we have mapped glacial deposits left by the Pierre Sublobe in South Dakota and applied 10Be surface exposure age dating on boulders on moraine ridges associated with three distinct late Quaternary glacial drifts. The oldest and most extensive “Tazewell” drift produced variable 10Be surface exposure ages spanning 20–7 ka; the large range is likely attributable to moraine degradation and subsequent boulder exhumation. The oldest ages of about 20 ka are probably limiting minimum ages for the Tazewell moraine surfaces. By contrast, exposure ages of the youngest “Mankato” drift of the easternmost Pierre Sublobe tightly cluster at about 16 ka. This age for the Pierre Sublobe is consistent with the nearby Des Moines Lobe, suggesting both acted together.

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

2013 ◽  
Vol 25 (6) ◽  
pp. 804-820 ◽  
Author(s):  
R. Tolotti ◽  
C. Salvi ◽  
G. Salvi ◽  
M.C. Bonci
Keyword(s):  
Continental Slope ◽  
Ross Sea ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Geochemical Data ◽  
Flow Paths ◽  
Ice Flow ◽  
Quaternary Climate ◽  
History Of ◽  
Geochemical Analyses

AbstractCores 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 multi-proxy 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 palaeo-sub-bottom currents in this sector of the Ross embayment.

INSIGHTS INTO ROSS SEA WEST ANTARCTIC ICE SHEET DYNAMICS FROM IN SITU 14C

2016 ◽  
Author(s):  
Brent M. Goehring ◽  
◽  
Keir Nichols ◽  
Greg Balco ◽  
Claire Todd
Keyword(s):  
Ross Sea ◽  
Ice Sheet ◽  
Antarctic Ice Sheet ◽  
West Antarctic Ice Sheet ◽  
West Antarctic ◽  
Ice Sheet Dynamics

Late Quaternary Stratigraphy, Glacial Limits, and Paleoenvironments of the Marresale Area, Western Yamal Peninsula, Russia

2002 ◽  
Vol 57 (3) ◽  
pp. 355-370 ◽  
Author(s):  
Steven L. Forman ◽  
Ólafur Ingólfsson ◽  
Valery Gataullin ◽  
William Manley ◽  
Hanna Lokrantz
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Field Studies ◽  
Yamal Peninsula ◽  
Northern Eurasia ◽  
Terrestrial Environment ◽  
Quaternary Stratigraphy ◽  
Ice Sheet Dynamics ◽  
Late Weichselian ◽  
The Yamal Peninsula

AbstractStratigraphic records from coastal cliff sections near the Marresale Station on the Yamal Peninsula, Russia, yield new insight on ice-sheet dynamics and paleoenvironments for northern Eurasia. Field studies identify nine informal stratigraphic units from oldest to youngest (the Marresale formation, Labsuyakha sand, Kara diamicton, Varjakha peat and silt, Oleny sand, Baidarata sand, Betula horizon, Nenets peat, and Chum sand) that show a single glaciation and a varied terrestrial environment during the late Pleistocene. The Kara diamicton reflects regional glaciation and is associated with glaciotectonic deformation from the southwest of the underlying Labsuyakha sand and Marresale formation. Finite radiocarbon and luminescence ages of ca. 35,000 to 45,000 yr from Varjakha peat and silt that immediately overlies Kara diamicton place the glaciation >40,000 yr ago. Eolian and fluvial deposition ensued with concomitant cryogenesis between ca. 35,000 and 12,000 cal yr B.P. associated with the Oleny and the Baidarata sands. There is no geomorphic or stratigraphic evidence of coverage or proximity of the Yamal Peninsula to a Late Weichselian ice sheet. The Nenets peat accumulated over the Baidarata sand during much of the past 10,000 yr, with local additions of the eolian Chum sand starting ca. 1000 yr ago. A prominent Betula horizon at the base of the Nenets peat contains rooted birch trees ca. 10,000 to 9000 cal yr old and indicates a >200-km shift northward of the treeline from the present limits, corresponding to a 2° to 4°C summer warming across northern Eurasia.

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