Open Session - SWISS GEOSCIENCE MEETINGs

110
Symposium 2: Mineralogy-Petrology-Geochemistry
Figure.1 Chemical classification of samples from the sediments based on (A) log (SiO 2 /Al 2 O 3 ) vs. log (Na 2 O/K 2 O) diagram of Pettijohn et al.
(1972), and (B) the SiO 2 vs. (Na 2 O/K 2 O) diagram of Roser and Korsch (1988) and (C) Ternary diagram of the parent rock of the sediments by
Nesbitt and Young, 1982.
2.3
Surface water in the Zermatt—Matterhorn area, Switzerland,
a hydrogeochemical study
Zhou Wei*, Stober Ingrid & Bucher Kurt
Institute of Mineralogy and Geochemistry University of Freiburg, D-79104, Freiburg, Germany
*wei.zhou@minpet.uni-freiburg.de
The chemical characteristics of surface runoff have been used to infer the mechanisms of solute acquisition in open system
environments. We studied the chemical evolution of surface waters in geologically diverse Alpine catchments of the Zermatt-
Matterhorn area. Two hydrogeochemical models have been set up for interpreting the water-rock interaction.
Water samples were collected mainly from small water bodies located in the Findeln glacier area and two river systems,
Mattervispa (Theodul) and Mellichenbach (Täsch valley) representing the geographical and lithological diversity. Altitudes of
sampling locations were around 1600m to 3200m. Since water samples were from water bodies at high elevation, water-rock
interaction was little affected by anthropogenic or biologic contributions.
Temperature, pH, and electric conductivity were measured on site. Charge balance of the analysis was better than 8%. Total
dissolved solids was relatively low and varies from 6 to 244 mg/l. Dominant solutes are Ca, Mg, HCO 3 , SO 4 and minor components
are Na, K, NO 3 , Cl and Si, while F and B occur in traces only.