research product . 2020

An 83 000 year old ice core from Roosevelt Island, Ross Sea, Antarctica

Lee, James E.; Brook, Edward J.; Bertler, Nancy A. N.; Buizert, Christo; Baisden, Troy; Blunier, Thomas; Ciobanu, V. Gabriela; Conway, Howard; Dahl-Jensen, Dorthe; Fudge, Tyler J.; ...
Open Access English
  • Published: 02 Sep 2020
Abstract
In 2013, an ice core was recovered from Roosevelt Island in the Ross Sea, Antarctica, as part of the Roosevelt Island Climate Evolution (RICE) project. Roosevelt Island is located between two submarine troughs carved by paleo-ice-streams. The RICE ice core provides new important information about the past configuration of the West Antarctic Ice Sheet and its retreat during the most recent deglaciation. In this work, we present the RICE17 chronology and discuss preliminary observations from the new records of methane, the isotopic composition of atmospheric molecular oxygen (δ18O-Oatm), the isotopic composition of atmospheric molecular nitrogen (δ15N-N2) and total air content (TAC). RICE17 is a composite chronology combining annual layer interpretations, gas synchronization, and firn modeling strategies in different sections of the core. An automated matching algorithm is developed for synchronizing the high-resolution section of the RICE gas records (60–720 m, 1971 CE to 30 ka) to corresponding records from the WAIS Divide ice core, while deeper sections are manually matched. Ice age for the top 343 m (2635 yr BP, before 1950 C.E.) is derived from annual layer interpretations and described in the accompanying paper by Winstrup et al. (2017). For deeper sections, the RICE17 ice age scale is based on the gas age constraints and the ice age-gas age offset estimated by a firn densification model. Novel aspects of this work include: 1) stratigraphic matching of centennial-scale variations in methane for pre-anthropogenic time periods, a strategy which will be applicable for developing precise chronologies for future ice cores, 2) the observation of centennial-scale variability in methane throughout the Holocene which suggests that similar variations during the late preindustrial period need not be anthropogenic, and 3) the observation of continuous climate records dating back to ∼ 65 ka which provide evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.
Communities
  • European Marine Science Marine Environmental Science : Arctic Sea Ice and Greenland Ice Sheet Sensitivity
Funded by
NSF| Collaborative Research: Deglaciation of the Ross Sea Embayment - constraints from Roosevelt Island
Project
  • Funder: National Science Foundation (NSF)
  • Project Code: 0944307
  • Funding stream: Directorate for Geosciences | Division of Polar Programs
,
NSF| Roosevelt Island Climate Evolution Project (RICE): US Deep Ice Core Glaciochemistry Contribution (2011- 2014)
Project
  • Funder: National Science Foundation (NSF)
  • Project Code: 1042883
  • Funding stream: Directorate for Geosciences | Division of Polar Programs
,
EC| ICE2ICE
Project
ICE2ICE
Arctic Sea Ice and Greenland Ice Sheet Sensitivity
  • Funder: European Commission (EC)
  • Project Code: 610055
  • Funding stream: FP7 | SP2 | ERC
,
NSF| Collaborative Research: Antarctic Climate Reconstruction Utilizing the US ITASE Ice Core Array (2009- 2012)
Project
  • Funder: National Science Foundation (NSF)
  • Project Code: 0837883
  • Funding stream: Directorate for Geosciences | Division of Polar Programs
,
NSF| Collaborative Research: Deglaciation of the Ross Sea Embayment - constraints from Roosevelt Island
Project
  • Funder: National Science Foundation (NSF)
  • Project Code: 0944021
  • Funding stream: Directorate for Geosciences | Division of Polar Programs
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