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Titus, D.D., 1997

Isotopic composition of vent discharge from the Matanuska Glacier, Alaska: Implications for the origin of basal ice

Bibliographic Reference

Titus, D.D., 1997, Isotopic composition of vent discharge from the Matanuska Glacier, Alaska: Implications for the origin of basal ice: East Lansing, Michigan, Michigan State University, M.S. thesis, 35 p.

Abstract

Basal ice at the Matanuska Glacier, Alaska, is characterized by elevated 3H concentrations and less negative Δ18O and ΔD values relative to englacial ice. Recently it has been suggested that basal ice is partially composed of modern meteoric water and forms as subglacial discharge moves out of an overdeepening resulting in supercooling of the discharge and nucleation of ice crystals. Values of Δ18O, ΔD and 3H were measured in subglacial discharge collected during the summer of 1995 from vents along the ice margin at the Matanuska Glacier. Application of a simple open system freezing fractionation model indicates that 18O, D, and 3H in discharge are within the requisite ranges to form basal ice, and that there is a genetic relationship between the two. Additionally, the temporal variability of Δ18O in the basal ice can be attributed to annual deviations in relative amounts of precipitation and meltwater present in subglacial discharge.

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