Dating of an East Antarctic ice core (GV7) by high resolution chemical stratigraphies

• Main Authors: Nardin, Raffaello, Severi, Mirko, Amore, Alessandra, Becagli, Silvia, Burgay, Francois, Caiazzo, Laura, Ciardini, Virginia, Dreossi, Giuliano, Frezzotti, Massimo, Hong, Sang-Bum, Khan, Ishaq, Narcisi, Bianca Maria, Proposito, Marco, Scarchilli, Claudio, Selmo, Enricomaria, Spolaor, Andrea, Stenni, Barbara, Traversi, Rita
• Format: Text
• Language: English
• Published: 2021
• Subjects: Antarctic; Antarc*; ice core
• Online Access: https://doi.org/10.5194/cp-2021-44; https://cp.copernicus.org/preprints/cp-2021-44/

Ice core dating is the first step for a correct interpretation of climatic and environmental changes. In this work, we release a stratigraphic dating of the uppermost 197 m of the 250 m deep GV7(B) ice core (drilling site, 70°41’S, 158°52’E, 1950 m a.s.l.) with a sub-annual resolution. Chemical stratigraphies of NO 3 − , MSA (methanesulfonic acid), non-sea salt SO 4 2− , sea-salt ions and the oxygen isotopic composition (δ 18 O) were used in the annual layer counting upon the identification of a seasonal profile in their records. Different procedures were tested and thanks to the volcanic history of the core, obtained in previous works, an accurate age-depth correlation was obtained for the period 1179–2009 CE. Once the dating of the core was finalized, the annual mean accumulation rate was evaluated throughout the analyzed 197 m of the core, obtaining an annually resolved history of the snow accumulation on site in the last millennium. A small, yet consistent, rise in accumulation rate was found for the last 830 years since the middle of the 18 th century.