Bubble observations and analysis of the Renland ice core
Bubbles in ice cores store various information about climate conditions during densification and pore close-off in former times. Very recently it was shown that bubbles can additionally be used as marker for cumulated strain within the ice. Bubble studies on the Renland ice core are from particular interest: the Renland ice core includes the oldest bubbly ice retrieved so far in ice core drilling projects and it contains bubbly ice that has been exposed to tremendous deformation and thinning. The Renland ice core of 584 m length was drilled through the ice cap during May-June 2015 in the framework of RECAP (Renland ice cap drilling project). The ice shows no clathrate formation. Preliminary considerations suggest Holocene and Glacial ice with Eemian ice close to bedrock. Core sections of the Renland ice core from selected depth intervals are measured with the means of X-ray computer tomography using the core-scale AWI-ICE CT. The measurements are performed with a spatial resolution of 15µm and provide 3d- bubble arrangements. Different bubble shape factors, bubble volume (porosity), bubble centre distributions and bubble next neighbor functions are derived. We present first depth profiles of these parameters and discuss the results in context of deformation mechanism and paleo climate. It will contribute to reconstruct the complex deformation history of the Renland ice cap.
Helmholtz Research Programs > PACES II (2014-2020) > TOPIC 3: The earth system from a polar perspective > WP 3.1: Circumpolar climate variability and global teleconnections at seasonal to orbital time scales