Solute Acquisition in Glacial Melt Waters. I. Fjallsjökull (South-East Iceland): Bulk Melt Waters with Closed-System Characteristics

Abstract

Variations in dissolved cations, total alkalinity, sulphate, and field pH are recorded for samples of precipitation, supraglacial melt, and bulk melt waters (those emerging at the portal) from Fjallsjökull (south-east Iceland). The composition of supraglacial melt indicates derivation from precipitation by the acquisition of solutes from the weathering and dissolution of rock debris, in a system open to atmospheric carbon dioxide. Bulk melt waters have variable compositions, approaching saturation with calcite, which can be derived from supraglacial melt water by continued solute acquisition in a system closed to atmospheric carbon dioxide. Solute–discharge relationships suggest that chemical evolution of the bulk melt waters occurs when aggressive englacial waters are mixed with the solute and sediment-rich subglacial component. Simple mixing behaviour occurs over intermediate discharges as long as variations in the extent of post-mixing evolution are small compared to changes in the mixing ratio.

Glacier hydrochemistry, solute provenance, and chemical denudation at a surge-type glacier in Kuannersuit Kuussuat, Disko Island, West Greenland

“…Calcite dissolution from basaltic weathering has been reported to exert significant influence on glacier hydrochemistry (Raiswell and Thomas, 1984;Fairchild et al, 1999b), thus it is important to emphasize that no trace carbonates have been identified (detection limit is c. 0.2%), either in the pristine rock, the sediment deposits or the suspended sediment in the bulk meltwater.…”

Calculating the balance between atmospheric CO2 drawdown and organic carbon oxidation in subglacial hydrochemical systems

“…Disko, Greenland [ Yde et al ., ], Rhone Glacier, Switzerland [ Hosein et al ., ], South Cascade Glacier, USA [ Reynolds and Johnson , ], Gangorti, Himalaya [ Singh et al ., ], and Satopanth, Himalaya [ Singh and Hasnain , ], all have water chemistries that plot on both sides of the open system line. The chemistry of Fjallsjökull, Iceland [ Raiswell and Thomas , ], diverges substantially from the open system line, implying closed system depletion of CO 2 . But its high alkalinity suggests substantial open system behavior occurred before closure.…”

The hydrochemistry of meltwaters draining a polythermal‐based, high Arctic glacier, south Svalbard: I. The ablation season

“…12, 1825±1849 (1998) Mean ratios of * Ca 2 : * Mg 2 and Na : Cl 7 have been determined for bulk, upwelling and conduit meltwaters and are presented in Table IV. The pCO 2 signature of a solution re¯ects the rate at which CO 2 diuses into or out of solution relative to the rate of other chemical weathering reactions (Raiswell, 1984;Raiswell and Thomas, 1984;Thomas and Raiswell, 1984). The so called``sulfate mass fraction'' (SMF) of meltwater samples has also been derived in the following manner: Table IV.…”