According to my sources, the original form is Iracema (with a "c") and Irasema (with an "s")is a variant. It comes from tupí language, means "honey exit" or "bee exit" and is the name of the native novel "Iracema", written by
José de Alencard. Also the name Iracema is anagram for
America.
Hope it helps.
Profe.