Minor and trace elements as indicators of solute provenance and flow routing in a subglacial hydrological system

The utility of minor and trace elements for subglacial solute-provenance and hydrological flow-routing studies is investigated at Haut Glacier d'Arolla (HGA), Switzerland. Principal component analysis (PCA) applied to the bulk meltwater chemistry indicates the concentration of most major ions, and some minor and trace elements (Sr, Mo, Ti) are inversely related to bulk meltwater discharge and have a clear hydrological control. Conversely, many other minor and trace elements have no clear relationship with meltwater discharge. This suggests that such solutes are affected by physico-chemical controls such as sorption, (oxy)hydroxide formation and co-precipitation reactions, in addition to any simple hydrological influence. PCA applied to rock digests and water-rock interaction experiments indicates the complexity of determining the lithogenic source of minor and trace elements from subglacial chemical weathering processes. This reflects the complex aqueous mobility of many minor and trace elements and the heterogeneous geology of the HGA catchment. However, the study suggests that there is potential in minor and trace elements for solute-provenance and flow-routing studies in glacierized catchments underlain by a more homogeneous geology.