Isotopic composition and origin of lacustrine brines in the Arctic

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Pagé, P., Michaud, J., Ouellet, M., Dickman, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1987
• Subjects: General Earth and Planetary Sciences; Arctic; Cornwallis; Little Cornwallis Island; Cornwallis Island; Arctic Archipelago
• Online Access: http://dx.doi.org/10.1139/e87-023; http://www.nrcresearchpress.com/doi/pdf/10.1139/e87-023

Meromictic lakes in the Arctic Archipelago were analyzed to determine whether the isotope content of the water molecule might confirm their oceanic origin. The 25 m bottom layer of Lake Garrow, on Little Cornwallis Island, is filled with a homogeneous sodium chloride solution with 2.6 times the chloride concentration of seawater (52 g L −1 ). Its δ 18 O value is around −10‰ with respect to V-SMOW, and its δ 2 H is eight times the oxygen value (~ −85‰). In Lake Sophia on Cornwallis Island, the deep stratum (25 m thick) is less concentrated (35 g L −1 Cl −1 ) and shows slightly higher δ 18 O and δ 2 H values (−9 and −75‰, respectively).Chemocline and surficial waters result from mixing between bottom waters and meteoric waters. The chemical and isotopic signals are interpreted as evidence of diagenesis through subpermafrost or intrapermafrost freezing of aquifers once filled with seawater, at some time during postglacial emergence.