This is kind of interesting to me because there are several absolutely a clear mineralogical change that meets this requirement:
But to merit inclusion on the geological scale, any time interval needs to meet certain criteria, such as having a clear, objective starting point in the mineral record.
With maybe the undoubted introduction of plastics into the earths crust as a mineral. Future scientists will absolutely be able to time this change globally because in geological terms, plastics will have been introduced 'everywhere' at about the same time. It will be a distinct marker that can be used to effectively time mass extinctions and a massive change to the atmospheric concentration of CO2.