Hi
Andrew,
Karrianne reminds me of Karianne which is a Norwegian and Danish combination of
Kari and
Anne.
http://www.nordicnames.de/flick_k/Katharina.html (scroll down to "combinations")
So I'd guess Karrianne is a combination of Karri (
Carrie) and
Anne,
/
Satu
http://www.nordicnames.de/