Effect of periodic melting on geochemical and isotopic signals in an ice core from Lomonosovfonna, Svalbard

• In this work we examine the quality of the atmospherically deposited signals in an ice core taken from a periodically melting ice field, Lomonosovfonna on central Spitsbergen, Svalbard. The aim is to investigate how much the atmospheric deposited signals in the stratigraphy of ice pack are changed by periodic melting of the ice. To determine the impact of this melting on the stratigraphy found in the ice core, we use three diagnostics: 1) Association between peak values in the ice chemical and isotopic record and ice facies type; 2) Number of “annual” cycles in these records compared with independently-determined number of years represented in the ice core; 3) Statistical comparison between the isotopic record in the ice core and the isotope records from coastal stations from the same region. We find that during warm summers as much as 50% of the annual accumulation may melt and percolate into the firn, and in a median year this decreases to ca. 25 %. As a consequence of percolation the most mobile acids show upto 50 % higher concentrations in bubble poor ice facies compared with facies that are less affected by melt. Most of the other chemical species are less affected than the strong acids, and the stable water isotopes show little evidence of mobility Annual, or bi-annual cycles are detected in most parameters, and the water isotope record has a comparable statistical distribution to isotopic records from coastal stations. We conclude that ice cores from sites like Lomonosovfonna preserve an useful environmental record despite melt events and percolation, where most parameters displays an annual, or in poor cases a bi-annual atmospheric signal.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Naturgeografi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Physical Geography (hsv//eng)

Nyckelord

Physical geography

Naturgeografi

Publikations- och innehållstyp

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