Unravelling Antarctica's past through the stratigraphy of a deep ice core: an image-analysis study of the EPICA-DML line-scan images

• Published in: Quaternary International
• Main Authors: Morcilloa, Gonzalo, Faria, Sérgio Henrique, Kipfstuhl, Sepp
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eElsevier 2020
• Subjects: Antarctic; The Antarctic; Dronning Maud Land; Antarc*; Antarctica; DML; EPICA; ice core; Ice Sheet
• Online Access: https://epic.awi.de/id/eprint/54248/; https://www.sciencedirect.com/science/article/abs/pii/S1040618220303815?via%3Dihub; https://hdl.handle.net/10013/epic.8e5b7daf-63bb-4a3b-a5da-e6b5c3e83ee4

Polar ice research has undergone great progress in the last six decades. One of its recent technological achievements has been the development of new techniques for digital image recording and analysis of ice-core stratigraphy and microstructure. In this work we investigate one such image records, namely the line-scan image records of the EPICA-DML (European Project for Ice Coring in Antarctica, Dronning Maud Land) deep ice core. These images provide a multiscale depiction of the stratigraphy and structure of the Antarctic Ice Sheet. While previous studies have focused on the ice-core optical stratigraphy on the micro- and mesoscale (<1 mm and 10−3–1 m, respectively), in this work we present several methods to obtain fast and reliable information on the ice-core stratigraphy on the macroscale (1–103 m), including the full ice-sheet thickness. The paleoclimatic relevance of the ice-core optical stratigraphy on the macroscale is demonstrated through the comparison of the line-scan grey-value record of the EPICA-DML deep ice core with its mineral dust record, which is used as a proxy for microinclusions and for several other types of climate proxies. Additionally, we introduce a novel method to estimate the macroscopic air-bubble concentration (including number and size of bubbles) in ice cores, which is simpler, faster, and almost as reliable as painstaking microscopic studies. After a brief excursion on the relation between macroscopic and mesoscopic measures of optical stratigraphy, we close this work by making the case for a multi-measure analysis of ice-core line-scan images, which enables us to obtain a broad perspective of the optical stratigraphy of the whole ice core, with relevance for paleoclimate and ice-sheet-flow studies.