Structural changes in silicate melt: A record from high-field strength elements in the Himalayan Cenozoic leucogranites

Most Himalayan Cenozoic leucogranites are peraluminous magmas that have experienced various degrees of fractional crystallization. These characterized by relatively high heterogeneity in their elemental compositions. As the melt’s Zr/Hf ratio passes ∼20, there is an apparent change from positive to negative correlation between Zr (or Hf) and ratio. Nb/Ta ∼5, Nb first decreases then increases, but Ta slowly increases drastically increases. Such systematic geochemical variations related changes dissolution behavior key accessory phases, which consequence silicate melt structural associated with crystallization and. a granitic magma evolves, structure as shown compositional parameters (e.g., NBO/T, A/CNK, M/F) well ratios. When 20 5, respectively, M/F, A/CNK decrease increase; A/NK C/NK become nearly constant; Na/K becomes constant Moreover, substantial leads viscosity, turn melts. Finally, such result mineralization economically relevant rare elements leucogranites.