Unveiling the anatomy of Termination 3 using water and air isotopes in the Dome C ice core, East Antarctica

• Published in: Quaternary Science Reviews
• Main Authors: Bréant, Camille, Landais, Amaëlle, Orsi, Anaïs, Martinerie, Patricia, Extier, Thomas, Prié, Frédéric, Stenni, Barbara, Jouzel, Jean, Masson-Delmotte, Valérie, Leuenberger, Markus
• Other Authors: Orsi, Anaï, Extier, Thoma
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Antarctic temperature; Bipolar seesaw; Deglaciation; Firn densification model; Heinrich like event; Ice core; Termination 3; Water and air isotope; Settore GEO/08 - Geochimica e Vulcanologia; Antarctic; East Antarctica; Antarc*; Antarctica; EPICA; ice core
• Online Access: http://hdl.handle.net/10278/3711754; https://doi.org/10.1016/j.quascirev.2019.03.025

Each glacial –interglacialtransition of the Quaternary occurs in a differentorbitalcontext leading to various timing for thedeglaciationand sequence of high vs low latitudes events. Termination 3, 250 kyears before present (ka), is an unusual deglaciation in the context of the last 9 deglaciations recorded in the old EPICA Dome C (EDC) Antarctic ice core: it exhibits a three-phase sequence, two warming phases separated by a small cooling, the last phase suggesting a particularly rapid temperature increase. We present here new high resolution δ15N anddeuteriumexcess (d-excess) data from the EDC ice core to provide a detailed temperature change estimate during this termination. Then, we combined the δD and δ18O to discuss the relationship betweenhigh and low latitudechanges through the d-excess. We also provide the high vs low latitude sequence of events over this deglaciation without chronological uncertainty using low latitude ice core proxies. In agreement with previous studies based onspeleothemanalyses, we show that the first phase of Termination 3 (256–249 ka) is associated with small Heinrich like events linked to changes inITCZposition,monsoonactivity andteleconnectionswith Antarctica. In a context of minimumNorthern Hemisphereinsolation, this leads to a rather strong Antarctic warming, as observed in the δ15N record in contrast to the relatively small δD increase. The second warming phase occurs during the rise of the Northern hemisphere insolation, with a large Heinrich like event leading to the characteristic Antarctic warming observed in the δ15N and δD increase as for the more recent terminations.