Marzie is one of two 'treasure hunters' who attempted to go north through the primal area prior to Lacie's arrival. However, unlike her partner, whose corpse can likely be found strewn about an area within the area containing the primals where the trail of petals ends, Marzie's fate remains a mystery for the most part.
Marzie and her partner are only mentioned through the notes which the partner leaves for Marzie (labeled treasure hunter's notes 1-4 and treasure hunter's letter which detail serve to clue Lacie into one way of heading north through the Primal paddock).