supersedure vs supersession

supersedure and supersession both are nouns.

Word	Noun	Adjective	Verb	Adverb
supersedure	Yes	No	No	No
supersession	Yes	No	No	No

As nouns, supersedure and supersession are synonyms defined as:

supersedure and supersession: act of replacing one person or thing by another especially one held to be superior

supersedure (noun)	supersession (noun)
act of replacing one person or thing by another especially one held to be superior	act of replacing one person or thing by another especially one held to be superior