The horizon classification is as follows:
Lithologicaldiscontinuity Horizon Subdivsionofhorizon Horizonsuffix
There is one exception to this format, when horizon suffix p is present then Horizonsuffix precedes Subdivsionofhorizon (e.g Ap2). note: Horizonsuffix p can only be present in the A horizon.
Lithologicaldiscontinuity: Is a digit prefixed to the horizon starting from 2 onwards.
Examples: 2B, 3B, 4B, …
Horizon: can only include one or two capital letters, the / character and a single digit. When two letters are present they can can be contiguous or separated by /.
Examples: A, AB, A/B, A1
Subdivsionofhorizon: single digit that follows after an alphanumeric combination for horizon (e.g A24, where A2 is the horizon and 4 is the subdivision). Subdivision can only be present when a single digit is already present in the horizon.
Horizonsuffix: minor case letter or ? prefix to the horizon after the numeric suffix, except for the p prefix which follows immediately Horizon and only applies to the A horizon (Ap2).
Examples: B2b, O2a, Ap1