Glacier naled evolution and relation to the subglacial drainage system based on water chemistry and GPR surveys (Werenskioldbreen, SW Svalbard)

Abstract

ABSTRACT. Glacier naledi are extrusive ice masses that appear in front of glaciers as a consequence of refreezing of meltwater seepage during the accumulation season. These structures provide a unique opportunity to understand subglacial drainage activity during the accumulation season; however, only few detailed studies have previously focused on their characteristics. Here, we investigated glacierderived naled assemblages in the proglacial zone of the polythermal glacier Werenskioldbreen (27.4 km 2 ) in SW Svalbard. We determined the spatial distribution of naledi using ground penetrating radar surveys. The main subglacial drainage pattern was related to a channel under the medial moraine, and three sources are linked to a distributed subglacial drainage network. The relation between atmospherically-corrected (Ca 2+ + Mg 2+) and (SO 4 2− ) in sub-naled waters was closely related to sulphide oxidation coupled with carbonate dissolution (r = 0.99; slope = 1.6). This is consistent with the local lithology, which is dominated by schist containing carbonates. We also found high carbonate saturation indices in pale white ice layers within the naled. We conclude that sulphide oxidation coupled with carbonate dissolution is the dominant chemical weathering process in the subglacial drainage system of Werenskioldbreen during the accumulation season.

Carbonate and silicate weathering in glacial environments and its relation to atmospheric CO2 cycling in the Himalaya

“…The H 4 SiO 4 concentration was not available for the Dokriani glacier (Hasnain and Thayyen, 1999). We assumed the water temperature to be 0.01°C for the glacial meltwater (Stachnik and others, 2016b). Additionally, water temperature data were not provided in most previous studies from glacierised basins in the Himalaya.…”

Which Drivers Control the Suspended Sediment Flux in a High Arctic Glacierized Basin (Werenskioldbreen, Spitsbergen)?

“…Its hydrological situation, including the location of the main subglacial outflows, largely corresponds to the drainage model described by Pälli et al [22] and improved by Grabiec [32]. Moreover, the ablation season meltwater chemistry of the glacier-fed icings shown by Stachnik et al [33] indicates the existence of several independent subglacial channel systems. Outflows from the Werenskioldbreen take the form of karst springs, geysers, and a type Röthlisberberger (R) subglacial outflow channel.…”

“…In the central part of the glacier foreland, subartesian outflows emerge from inactive glacier ice (called the Black and the Second Black Spring). The Angelisen subglacial drainage system is separate and its outflow is located near the southern margin of the glacier [33]. All streams in the proglacial area are combined and create the Breelva River.…”

Aluminium in glacial meltwater demonstrates an association with nutrient export (Werenskiöldbreen, Svalbard)

“…Spatial differences in silicate weathering are not reflected in spatial difference in Al concentrations in the Werenskiöldbreen basin. Present studies acknowledge that carbonate and silicate weathering in glacierised basins are driven by sulphide oxidation (Equations , ; Tranter et al, ; Stachnik, Yde, Kondracka, Ignatiuk, & Grzesik, ), carbonate and silicate hydrolysis (Equations , ; Yde et al, ) carbonation by CO 2 sourced from organic carbon oxidation (Equation ; Wadham et al, ) or carbonation of carbonate and silicate (Equations , ; Tranter et al, ). At Werenskiöldbreen, the dominant role of sulphide oxidation in carbonate weathering under subglacial conditions was confirmed, but that of sulphide oxidation combined with silicate weathering (SOSW) is less clear (Stachnik et al, ).…”