A burnt layer or burned layer in archaeology is a

stratum In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

of earth that was formed primarily by the burning of objects or buildings. The extent of the layer is irrelevant. It can be the remains of a campfire as well as the remains of a burned down settlement. Burnt layers are recorded in event stratigraphy, a sub-area of stratigraphy.''Event stratigraphy''
at quaternary.stratigraphy.org. Retrieved 10 December 2021.

References

Methods in archaeology {{archaeology-stub