Supporting other calendars and temporal coordinate-systems (e.g. geological timescale) was one of the primary issues that led to the revision of OWL-Time in 2017, and updated once since. In fact I wrote a whole paper about it published in SWJ. Of course this solution is not compatible with ISO 8601 - which only deals with the conventional calendar.
There has been a comment in https://github.com/ESIPFed/science-on-schema.org/issues/159 regarding non-gregorian time.
Supporting other calendars and temporal coordinate-systems (e.g. geological timescale) was one of the primary issues that led to the revision of OWL-Time in 2017, and updated once since. In fact I wrote a whole paper about it published in SWJ. Of course this solution is not compatible with ISO 8601 - which only deals with the conventional calendar.