Sigríður Níelsdóttir is one of my favorite artists over the age of 70. She didn't start recording her music until her early seventies. Despite this, she is one of Iceland's most prolific artists with over 20 albums to her name. Her music has influenced many of Iceland's great musicians including Bjork and Mum. Icelandairways did a 3 part podcast interview with her. I've included the youtube links below.