We have already examples of glassy ground on Earth: volcanic eruptions can give as an outcome obsidian ground, which is basically basaltic glass.

Weathering and erosion make it possible for vegetation to grow back on this soil after few years, following a well established sequence: first pioneer plants, followed by more diverse vegetation.

After 1300 years is very likely you will have to dig dip to find traces of the vitrified soil (look at Pompei)

We already have examples of glassy ground on Earth: volcanic eruptions can give as an outcome obsidian ground, which is basically basaltic glass.

Weathering and erosion makes it possible for vegetation to grow back on this soil after a few years, following a well established sequence: first pioneer plants, followed by more diverse flora.

After 1300 years is very likely you will have to dig deep to find traces of the vitrified soil (look at Pompei).