  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.
