upthrust vs ascension

upthrust and ascension both are nouns.

Word	Noun	Adjective	Verb	Adverb
upthrust	Yes	No	No	No
ascension	Yes	No	No	No

As nouns, ascension is a hypernym of upthrust; that is, ascension is a word with a broader meaning than upthrust:

upthrust: (geology) a rise of land to a higher elevation (as in the process of mountain building)
ascension: a movement upward; rise above the ground

Other hypernyms of upthrust include ascent, rise, rising.

upthrust (noun)	ascension (noun)
(geology) a rise of land to a higher elevation (as in the process of mountain building)	the act of changing location in an upward direction
	a movement upward; rise above the ground
	(astronomy) the rising of a star above the horizon