Preprints
https://doi.org/10.5194/cp-2024-38
https://doi.org/10.5194/cp-2024-38
10 Jun 2024
 | 10 Jun 2024
Status: this preprint is currently under review for the journal CP.

Drastic changes in Depositional Environments at the Ross Sea Continental Margin since the Mid-Pleistocene: More evidence for West Antarctic Ice Sheet collapse

Chinmay Dash, Yeong Bae Seong, Ajay Kumar Singh, Min Kyung Lee, Jae Il Lee, Kyu-Cheul Yoo, Hyun Hee Rhee, and Byung Yong Yu

Abstract. This study investigates a sediment core (RS15-LC47) from the Ross Sea continental rise to elucidate the sea-ice interaction and resulting paleodepositional changes over the past 800 ka. By integrating whole-core Magnetic Susceptibility (MS), sediment biogenic components (TOC, CaCO3, and biogenic silica), sedimentological features, and the isotopic ratio of authigenic beryllium (10Be/9Be)reac, we unravel the paleoenvironmental changes and their influence on the sedimentary processes. The lower segment of the investigated interval (750–550 ka) exhibits distinct lithological characteristics, including parallel and cross laminations, along with millimeter-scale faults, suggestive of contourite depositional processes. This section also displays irregular trends in MS values due to poorly sorted sediments, characteristics feature of sediment slumping. The lowest (10Be/9Be)reac ratio in this interval suggests reduced Circumpolar Deep Water (CDW) inflow due to strengthened Antarctic Slope Current (ASC). Although the Total Organic Carbon (TOC) is highest in this interval, high Carbon-to-Nitrogen (C/N) ratio and low Barium excess (Baex) suggests reduced marine productivity due to increased terrestrial input likely from advancing ice sheets. Following the Mid-Pleistocene Transition (MPT), MS values remain consistently low until MIS 8 (~250 ka) and (10Be/9Be)reac relatively increases, indicating persistent lukewarm condition. We hypothesize this timeframe favorable for ice-shelf disintegration and possible collapse of the West Antarctic Ice Sheet (WAIS). Between 550 and 250 ka, TOC/TN levels resemble those observed in the euphotic layer of the Ross Sea, with relatively higher Baex and TOC, indicating higher productivity during an extended lukewarm condition. During the late Pleistocene (> 250 ka), coarser grain size and IRD-rich layers suggest strengthening of bottom currents. The upwelling of CDW facilitated a drastic increase in the (10Be/9Be)reac ratio during the late Pleistocene. OpalMAR and TOC % exhibit positive trends with (10Be/9Be)reac during the late Pleistocene interglacials, suggesting increased productivity during warmer periods.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Chinmay Dash, Yeong Bae Seong, Ajay Kumar Singh, Min Kyung Lee, Jae Il Lee, Kyu-Cheul Yoo, Hyun Hee Rhee, and Byung Yong Yu

Status: open (until 05 Aug 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Chinmay Dash, Yeong Bae Seong, Ajay Kumar Singh, Min Kyung Lee, Jae Il Lee, Kyu-Cheul Yoo, Hyun Hee Rhee, and Byung Yong Yu
Chinmay Dash, Yeong Bae Seong, Ajay Kumar Singh, Min Kyung Lee, Jae Il Lee, Kyu-Cheul Yoo, Hyun Hee Rhee, and Byung Yong Yu

Viewed

Total article views: 131 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
95 30 6 131 4 3
  • HTML: 95
  • PDF: 30
  • XML: 6
  • Total: 131
  • BibTeX: 4
  • EndNote: 3
Views and downloads (calculated since 10 Jun 2024)
Cumulative views and downloads (calculated since 10 Jun 2024)

Viewed (geographical distribution)

Total article views: 125 (including HTML, PDF, and XML) Thereof 125 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 21 Jun 2024
Download
Short summary
This study explores sediment core RS15-LC47 from the Ross Sea over the past 800,000 years, examining changes in sea-ice dynamics and deposition environments. It integrates various data to reveal shifts related to Circumpolar Deep Water influx and Antarctic currents, particularly during significant climate transitions. Results highlight potential West Antarctic Ice Sheet collapses in warmer periods, offering new insights into the area's paleoclimate and sedimentary processes.