split up vs carve up

split up is a noun but carve up is not a noun.

Word	Noun	Adjective	Verb	Adverb
split up	Yes	No	Yes	No
carve up	No	No	Yes	No

As verbs, split up and carve up are synonyms defined as:

Other synonyms of split up include dissever, divide, separate, split.

split up (noun)	carve up (noun)
an increase in the number of outstanding shares of a corporation without changing the shareholders' equity

split up (verb)	carve up (verb)
become separated into pieces or fragments	separate into parts or portions
get a divorce; formally terminate a marriage
discontinue an association or relation; go different ways
separate into parts or portions