MESMERISE
iMpuritiES in the Microstructure of Eemian gReenlandic Ice via laSEr ablation

Plasma torch of a time of flight mass spectrometer to ionize ablated material.

Project

Ice cores drilled at the Greenland ice sheet are unique climate archives enabling the analysis of numerous paleo-proxies at up to seasonal resolution. Characterisation of ice-core impurities in high-temporal resolution is crucial for interpreting past environmental conditions, such as atmospheric chemistry and dust concentration, sea ice extent, volcanic eruptions, and forest fires. To date, only three Greenlandic ice cores cover part of the previous interglacial period – the Eemian (115-130 ka ago) – which was climatically warmer than the pre-industrial period.
A better understanding of the Eemian climate will put our present interglacial period – the Holocene – into an important climatic context and serves as a vital analogue for our current warming climate. Understanding the state of the Greenland ice sheet during the Eemian is thus crucial regarding the imminent socioeconomic and natural consequences of global warming in the Arctic, and future impacts on global sea level rise.

A) Deep ice cores in Greenland, the project ones are marked.
B) Sketch of LA-ICP-MS 2D Imaging on ice below -23°C. Impurity analysis via ICP-MS will be complemented by TOFMS.
C) Visual stratigraphy of large crystals in Eemian NGRIP ice and correlating chemical data displaying annual layers in a pilot study.
D) LA-ICP-MS 2D Imaging of four analytes in EGRIP ice with 20 μm resolution

Overall objective

This project's overall objective is to provide new and detailed climatic information about the Eemian period based on Greenland ice core records. The approach is to analyse Holocene and Eemian ice for soluble and insoluble chemical impurities by fully capitalising on a state-of-the-art experimental method: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). This method allows for ultra-high resolution 2D Imaging and the creation of 2D chemical images that provide information not achievable by conventional analytical techniques. The project thus takes place at the frontiers of analytical methods in ice core analysis. Using the latest advances in LA-ICP-MS, I will reveal to what degree annual layers are preserved and can be detected in Greenland Eemian ice. The systematic comparison to Holocene ice will provide an important baseline, especially for constraining how annual layers are affected by post-depositional processes over time, especially in the oldest ice. 

Procedure

The first part of the project will be carried out on samples from the central Greenland NGRIP and NEEM ice cores that contain the longest continuous sections of Eemian ice. Additional Eemian ice from the RECAP ice core will be analysed afterwards. This East Greenland ice core, drilled on the Renland ice cap, offers an essential complement for a coastal location and has indicated an increase in ice-free areas during the Eemian.
However, its deep ice parts are so far uncharacterised in terms of high-resolution signal preservation. The knowledge gained on signal preservation in deep ice will, among others, have future applications also for interpreting deep Antarctic ice, such as that obtained from the ongoing "Beyond EPICA-Oldest Ice" (BE-OI) ice coring project.

Secondments

  1. Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research with Prof. Pascal Bohleber
  2. Physics of Ice, Climate, and Earth, University of Copenhagen with Assoc. Prof. Anders Svensson
Ice core samples being packed away for analysis after cutting in the cold laboratory.
Horizontal of an ice core resulting in pieces for analysis.
Dust-rich bands ("cloudy bands") in Greenlandic ice made visible with the Visual Stratigraphy Line Scanner.

Team

Nicolas Stoll

Principal Investigator
Ca' Foscari University of Venice, Italy

Carlo Barbante

Supervisor
Ca' Foscari University of Venice, Italy

Pascal Bohleber

Supervisor
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Germany

Anders Svensson

Supervisor
University of Copenhagen, Denmark