Open AccessOrigin of stratified basal ice in outlet glaciers of Vatnajökull and Öræfajökull, Iceland
Author(s) -
LARSON GRAHAME J.,
LAWSON DANIEL E.,
EVENSON EDWARD B.,
KNUDSEN ÓSKAR,
ALLEY RICHARD B.,
PHANIKUMAR MANTHA S.
Publication year - 2010
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/j.1502-3885.2009.00134.x
Subject(s) - geology , glacier , geomorphology , ice stream , ice shelf , oceanography , cryosphere , sea ice
Larson, G.J., Lawson, D.E., Evenson, E.B., Knudsen, Ó., Alley, R.B. & Phanikumar, M.S. 2010: Origin of stratified basal ice in outlet glaciers of Vatnajökull and Öræfajökull, Iceland. Boreas , Vol. 39, pp. 457–470. 10.1111/j.1502‐3885.2009.00134.x. ISSN 0300‐9483. During the period 2000–2005, we collected samples of englacial ice, vent water, frazil/anchor ice and stratified basal ice from warm‐based outlet glaciers of Vatnajökull and Öræfajökull, Iceland, and analysed them for 3 H, 18 O and D. Results of 3 H analyses show that the stratified basal ice contains 3 H from atmospheric thermonuclear testing and is younger than the englacial ice. Results of the 18 O and D analyses show that frazil/anchor and stratified basal ice are both enriched by an average of 2.4‰ in 18 O and 11‰ in D relative to vent water. These values are consistent with fractionation during partial freezing of supercooled subglacial water in an open system, one in which the remaining water is continuously removed and replenished by water of similar composition. The isotopic data and field observations do not support either a regelation or a thermal ad‐freeze‐on origin for the stratified basal ice.