In most of Glorantha, there are not regular solar eclipses (only if you are directly under the Red Moon), but there has been one solar eclipse in Time – the Sunstop. Here’s a little more information:
The Black Sun
It is unknown if this is an actual celestial object, or if it is humans’ and other races’ misunderstanding cosmic events far beyond their ken. It appeared at the Sunstop, where it eclipsed the sun for an unknowable period of time, then disappeared when the Sun began moving again. It has not been seen since except in fevered anti-solar dreams. However, a large number of trolls and humans in Chen Durel (the Kingdom of Ignorance) worship a deity named Basko, who they claim inhabits this dark body.