Probing neutrino mixing angles with ultrahigh energy neutrino telescopes

We point out that detecting $\nuebar$'s from distant astrophysical sources with the up-coming and future neutrino telescopes using the Glashow resonance channel $\nuebar e^{-}\to W^{-} \to$ anything, which occurs over a small energy window around the $\nuebar$ energy of $\sim6.3\pev$, offers a new way of measuring or setting limits on neutrino mixing angles, in particular the angle $\theta_{12}$, thereby providing an independent experimental probe of neutrino mixing angles. We also discuss how this exercise may throw light on the nature of the neutrino production mechanism in individual astrophysical sources.