@article{2-s2.0-84963967731,

title = {Chemical denudation and the role of sulfide oxidation at Werenskioldbreen, Svalbard},

author = { Ł. Stachnik and E. Majchrowska and J.C. Yde and A.P. Nawrot and K. Cichała-Kamrowska and D. Ignatiuk and A.M. Piechota},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963967731&doi=10.1016%2fj.jhydrol.2016.03.059&partnerID=40&md5=221b35ed0f8ef7fbafa4c907ab3737c0},

doi = {10.1016/j.jhydrol.2016.03.059},

issn = {00221694},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Hydrology},

volume = {538},

pages = {177-193},

publisher = {Elsevier B.V.},

abstract = {This study aims to determine the rate of chemical denudation and the relationships between dominant geochemical reactions operating in the proglacial and subglacial environments of the polythermal glacier Werenskioldbreen (SW Svalbard) during an entire ablation season. Water sampling for major ion chemistry was performed at a proglacial hydrometric station and from subglacial outflows from May to September 2011. These data were combined with measurements of discharge and supraglacial ablation rates. The slopes and intercepts in best-fit regressions of [*Ca2+ + *Mg2+ vs. *SO42-] and [HCO3- vs. *SO42-] in meltwater from ice-marginal subglacial channels were close to the stoichiometric parameters of sulfide oxidation and simple hydrolysis coupled to carbonate dissolution (*concentrations corrected for input of sea-salt). This shows that these relationships predominates the meltwater chemistry. Our findings also show that sulfide oxidation is a better indicator of the configuration of subglacial drainage systems than, for instance, Na+ and K+. In the proglacial area and in sub-artesian outflows, the ion associations represent sulfide oxidation but other processes such as ion exchange and dissolution of Ca and Mg efflorescent salts may also contribute to the solute variations. These processes may cause enhanced fluxes of Ca2+ and HCO3- from glacierized basins during the early ablation and peak flow seasons as the proglacial salts re-dissolve. The overall chemical denudation rate in the basin for 2011 (ranging from 1601 to 1762 meq m-2 yr-1 (121.9 to 132.2 t km-2 yr-1)) was very high when compared to other Svalbard valley glaciers suggesting that the high rate of chemical denudation was mostly caused by the high rates of discharge and ablation. Chemical weathering intensities (876 and 964 meq m-3 yr-1) exceeded previously reported intensities in Svalbard. © 2016 Elsevier B.V..},

note = {35},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-84870752949,

title = {Reconstructing subglacial drainage of Werenskiold Glacier (SW Spitsbergen) based on numerical modelling [Rekonstrukcja drenażu subglacjalnego lodowca Werenskiolda (SW Spitsbergen) na podstawie modelowania numerycznego]},

author = { A.M. Piechota and S.S. Sitek and D. Ignatiuk and J.A. Piotrowski},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870752949&partnerID=40&md5=ffcd586c944f696e7b5046e0e507fffa},

issn = {08676143},

year  = {2012},

date = {2012-01-01},

urldate = {2012-01-01},

journal = {Biuletyn - Panstwowego Instytutu Geologicznego},

number = {451},

pages = {191-202},

abstract = {The paper attempts to describe subglacial drainage of the Werenskiold Glacier based on numerical modelling using FEFLOW software version 6.0. The model covers 36.2 km2 of a polythermal glacier basin, 75% of which is filled with ice (27.1 km2). Numerical modelling was preceded by field research carried out on Werenskiold during the summers of2009-2011. The model illustrates the subglacial drainage in a ground moraine layer and the top of the bedrock. Permafrost and active layer of a maximum thickness of 2 m under the glacier snout and in its forefield were assumed (Replewska-Pȩkalowa; 2004). The aim of this study was to obtain the subglacial groundwater flow field and the spatial distribution of hydraulic pressures beneath the glacier and in its forefield. The spatial distribution of hydraulic pressure and groundwater flow paths beneath the glacier are controlled by its geometry (thickness), thermal conditions, the amount of ablation and rainfall water, and the hydrogeological parameters of the bed. The water flux in the ablation season in the aquifer under the glacier and in its forefield was estimated at 4624 m 3/day, what corresponds to 8% of the seasonal ablation water and rainfall (5% of which drains through the sediments under the glacier). The remaining 92% of the ablation water is evacuated through inand subglacial channel system.},

note = {5},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-66149124906,

title = {Meltwater discharge through the subglacial bed and its land-forming consequences from numerical experiments in the Polish lowland during the last glaciation},

author = { J.A. Piotrowski and P. Hermanowski and A.M. Piechota},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66149124906&doi=10.1002%2fesp.1728&partnerID=40&md5=8402e0ed60a1edc64c81bce51b5b2c79},

doi = {10.1002/esp.1728},

issn = {01979337},

year  = {2009},

date = {2009-01-01},

journal = {Earth Surface Processes and Landforms},

volume = {34},

number = {4},

pages = {481-492},

abstract = {Numerical experiments suggest that the last glaciation severely affected the upper lithosphere groundwater system in NW Poland: primarily its flow pattern, velocities and fluxes. We have simulated subglacial groundwater flow in two and three spatial dimensions using finite difference codes for steady-state and transient conditions. The results show how profoundly the ice sheet modifies groundwater pressure heads beneath and some distance beyond the ice margin. All model runs show water discharge at the ice forefield driven by ice-sheet-thickness-modulated, down-ice-decreasing hydraulic heads. In relation to nonglacial times, the transient 3D model shows significant changes in the groundwater flow directions in a regionally extensive aquifer ca. 90 m below the ice-bed interface and up to 40 km in front of the glacier. Comparison with empirical data suggests that, depending on the model run, only between 5 and 24% of the meltwater formed at the ice sole drained through the bed as groundwater. This is consistent with field observations documenting abundant occurrence of tunnel valleys, indicating that the remaining portion of basal meltwater was evacuated through a channelized subglacial drainage system. Groundwater flow simulation suggests that in areas of very low hydraulic conductivity and adverse subglacial slopes water ponding at the ice sole was likely. In these areas the relief shows distinct palaeo-ice lobes, indicating fast ice flow, possibly triggered by the undrained water at the ice-bed interface. Owing to the abundance of low-permeability strata in the bed, the simulated groundwater flow depth is less than ca. 200 m. Copyright © 2009 John Wiley & Sons, Ltd.},

note = {35},

keywords = {},

pubstate = {published},

tppubtype = {article}

}