Stratigraphic templates for ice core records of the past 1.5 Myr

• Published in: Climate of the Past
• Main Authors: Wolff, Eric W., Fischer, Hubertus, Ommen, Tas, Hodell, David A.
• Format: Text
• Language: English
• Published: 2022
• Subjects: Antarctic; New Zealand; Antarc*; Antarctica; EPICA; ice core
• Online Access: https://doi.org/10.5194/cp-18-1563-2022; https://cp.copernicus.org/articles/18/1563/2022/

The international ice core community has a target to obtain continuous ice cores stretching back as far as 1.5 Myr. This would provide vital data (including a CO 2 profile) allowing us to assess ideas about the cause of the Mid-Pleistocene Transition (MPT). The European Beyond EPICA project and the Australian Million Year Ice Core project each plan to drill such a core in the region known as Little Dome C. Dating the cores will be challenging, and one approach will be to match some of the records obtained with existing marine sediment datasets, informed by similarities in the existing 800 kyr period. Water isotopes in Antarctica have been shown to closely mirror deepwater temperature, estimated from <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">Mg</mi><mo>/</mo><mi mathvariant="normal">Ca</mi></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="37pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="6a49333f4c0062578a4b6eb2e474aab0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-18-1563-2022-ie00001.svg" width="37pt" height="14pt" src="cp-18-1563-2022-ie00001.png"/></svg:svg> ratios of benthic foraminifera, in a marine core on the Chatham Rise near to New Zealand. The dust record in ice cores resembles very closely a South Atlantic marine record of iron accumulation rate. By assuming these relationships continue beyond 800 ka, our ice core record could be synchronised to dated marine sediments. This could be supplemented, and allow synchronisation at higher resolution, by the identification of rapid millennial-scale events that are observed both in Antarctic methane records and in emerging records of planktic oxygen isotopes and alkenone sea surface temperature (SST) from the Portuguese Margin. Although published data remain quite sparse, it should also be possible to match 10 Be ...