Ice composition evidence for the formation of basal ice from lake water beneath a cold-based Antarctic glacier

• Published in: Annals of Glaciology
• Main Authors: Lorrain, R., Fitzsimons, S., Vandergoes, M., Stiévenard, M.
• Other Authors: Université libre de Bruxelles (ULB), University of Otago Dunedin, Nouvelle-Zélande, Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Géochrononologie Traceurs Archéométrie (GEOTRAC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1999
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Annals of Glaciology; Antarc*; Antarctic; Suess Glacier
• Online Access: https://hal.science/hal-03120935; https://hal.science/hal-03120935/document; https://hal.science/hal-03120935/file/fichier10.pdf; https://doi.org/10.3189/172756499781822011

International audience Entrainment of debris by cold-based glaciers having basal temperatures as low as^17³C can be observed in the DryValleys of southVictoria Land, Antarctica.The classical models developed to explain debris incorporation at the glacier base are inappropriate in such cases, since the basal temperature is well below the freezing point. An alternative model, based on the presence of ice-marginal lakes, has recently been proposed by one of the authors (S.F.). In this model, transient wet-base conditions can occur as ice flows onto the unfrozen sediments of the lake bottom, creating conditions favorable to the entrainment of sediments and to ice accretion by water freezing. Here we describe a situation where this model is consistent with an ice-composition study of the basal part of Suess Glacier, Taylor Valley. The stable isotope composition indicates that water freezing, most probably lake water, plays a major role in the formation of the basal ice layers. Total gas content of this basal ice is considerably depleted when compared to meteoric glacier ice, in accordance with a rejection mechanism during freezing. Its gas composition, strongly enriched in CO 2 , is also indicative of the presence of a former liquid phase.