Major ion concentrations in spring water across Main Central Thrust in central Nepal

摘要: Thirteen springs were sampled across the Main Central Thrust (MCT) in vicinity of Syaule central Nepal, where schists and gneisses from Higher Himalayan Crystallines are carried over phyllites slates interbedded with calcareous bands Lesser Himalaya. The spring water carbonate units is characterised by a higher electrical conductivity temperature (around 20 °C). geochemistry dominated calcium magnesium carbonates as well calcium, magnesium, sulphate concentrations proportional basically to alkalinity. lower associated (Na+K)/(Ca+Mg) concentration ratio indicating predominance silicate alteration. conductivity, temperature, ion show remarkable spatial distribution an overall decrease south north unambiguous increase when entering Crystallines. at MCT larger than 5. also exhibit increasing trends rising altitude, which could be representative larger-scale patterns controlled geology. In terms its alkalinity ratio, sample clearly separated hot Nepal or other geothermal (e.g., Turkey France), characterized greater ratio. bridges gap between waters gneiss–metasediments contact French Alps various thermal andesitic La Soufriere volcano Guadeloupe. spatially coherent can provide information on large-scale fluid circulation active tectonic settings define baseline for search anomalous signatures geodynamic phenomena, such possible earthquake precursors, might observed. Jour. Nep. Geol. Soc., Vol. 37, 2008, 55-56