Paleomagnetism

 was a branch of geology and the main subject of the research that Dr Pam Cutler was involved with near Little Falls Lake, Minnesota in 1986. The discipline was at least partially founded on extremely tricky maths. (PROSE: Iceberg)

Behind the scenes
Unremarked in DWU fiction is the fact that paleomagnetism was, generally, the study of the shifting magnetism of the Earth, as evidenced in the world's oldest rocks.