Boron and Molybdenum Isotope Evidence for Source‐Controlled Compositional Diversity of Cenozoic Granites in the Eastern Tethyan Himalaya

The origins of Cenozoic granites in the Himalaya are key to understanding evolution Himalayan orogen. However, it is unclear whether these represent primary melts, and nature their magma source controversial. Here, we present a systematic element Sr–Nd–B–Mo isotope study from Yardoi area eastern Tethyan Himalaya, China. These can be divided into two groups: mid-Eocene porphyritic two-mica with low SiO2 contents (65.9−69.6 wt.%) adakitic geochemical signatures, Miocene equigranular high (71.6−75.5 wt.%). high-SiO2 (HSG) have similar Sr−Nd compositions low-SiO2 (LSG), but they distinct δ11B values −19.4‰ −11.4‰ −10.6‰ −6.89‰. This indicates that groups different sources, LSG derived by partial melting dominantly metamafic rocks at thickened lower crustal conditions, HSG generated mid-crust metasedimentary less enriched Nd compositions. δ98/95Mo highly variable −0.68‰ 0.12‰ −1.13‰ 0.46‰, respectively. correlate positively Sr/Y negatively K2O, Rb, Zr, Rb/Sr, reflecting addition external metamorphic fluids during anatexis metapelites. B–Mo data robustly suggest source-controlled compositional diversity granites, which could provide clues physical responses large