Hydrology of Ikka Fjord, Greenland
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Hydrology of Ikka Fjord, Greenland

Photo above: Florian Huber, SUBMARIS. River running into Ikka Fjord with musk oxen on the beach, 2021


Over 27 years, we have been collecting water samples from Ikka Fjord in SW Greenland on various expeditions between 1995 and 2022. These encompass samples of springs, rivers, lakes, seawater, and water extracted from the ikaite columns (referred to as ‘column water’). For a majority of the samples, stable isotope analysis have been performed. It’s this data that my former Masters supervisor Bjørn Buchardt from the University of Copenhagen have spent time on compiling and interpreting. This has led to this very nice article in the Bulletin of the Geological Society of Denmark:


Isotope hydrology (2H and 18O) of Ikka fjord and its tufa columns, SW Greenland

by

Buchardt, B., Stockmann, G., Hansen, M.O. & Sveinbjörnsdóttir, Á. 2024.
Bulletin of the Geological Society of Denmark, Vol. 73, pp. 135–156.
ISSN 2245-7070. https://doi.org/10.37570/bgsd-2024-73-08

Abstract: From 1995 to 2022, several expeditions have visited the small Ikka fjord in SW Greenland to study growth and stability of the more than 1000 submarine tufa columns build of the metastable, cold-water carbonate ikaite (CaCO3·6H2O). The different water types in the area have been sampled for geochemical and stable isotope (2H and 18O) investigations. Here we present the results of more than 300 isotope analyses of water from the fjord and from streams, lakes, springs and tufa columns. Fjord water samples identify a two-component mixing system (R2 > 0.99) between freshwater runoff and sea water entering from the Davis Strait. The fresh water samples have an average composition of –95.4‰ δ2H and –13.1‰ δ18O. We f ind both seasonal and altitude effects in fresh water related to early (June–July) or late (August) sampling time. All freshwater samples excluding lakes but including previous precipitation data (GNIP, 1963–1974) can be described by a Local Meteoric Water Line with slope of 6.43 ± 0.12 and offsets between 6.34 and 6.56. Column water samples are mixed with fjord water but extrapolation to a chlorine-free composition defines an endmember composition of –102‰ δ2H and –14.2‰ δ18O. These composi tions identify precipitation on top of the igneous plateau at ~ 500 m altitude as the source for the column water.

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Keywords: Hydrogen and oxygen isotopes, meteoric water, fjord water, tufa columns, Ikka fjord, SW Greenland.

Photo: Eemu Ranta, 2018. Gabrielle taking water samples of springs in Ikka Fjord.
Photo: Erik Sturkell, 2014. Gabrielle measuring the pH of the water running down the Skrå Kløft gully.