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Noble gas signatures in Greenland: Tracing glacial meltwater sources
Author(s) -
Niu Yi,
Castro M. Clara,
Aciego Sarah M.,
Hall Chris M.,
Stevenson Emily I.,
Arendt Carli A.,
Das Sarah B.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065778
Subject(s) - meltwater , glacial period , geology , greenland ice sheet , ice sheet , glacier , noble gas , atmosphere (unit) , atmospheric sciences , geomorphology , meteorology , chemistry , physics , organic chemistry
This study represents the first comprehensive noble gas study in glacial meltwater from the Greenland Ice Sheet. It shows that most samples are in disequilibrium with surface collection conditions. A preliminary Ne and Xe analysis suggests that about half of the samples equilibrated at a temperature of ~0°C and altitudes between 1000 m and 2000 m, with a few samples pointing to lower equilibration altitudes and temperatures between 2°C and 5°C. Two samples suggest an origin as melted ice and complete lack of equilibration with surface conditions. A helium component analysis suggests that this glacial meltwater was isolated from the atmosphere prior to the 1950s, with most samples yielding residence times ≤ 420 years. Most samples represent a mixture between a dominant atmospheric component originating as precipitation and basal meltwater or groundwater, which has accumulated crustal 4 He over time.