Origin of Ilmenite sands in the Thule region

Beach sands along the shores of Steensby Land in North-West Greenland are very rich in ilmenite and a potential source for titanium. Why are the deposits so rich in ilmenite and with little accompanying magnetite?

Recent work by GEUS shows that the source rocks contain two types of ilmenite and very little magnetite. Ilmenite crystallised as a primary phase in basaltic hosts but formed also by exsolution in primary and titanium-rich magnetite. In the host rocks, the remaining and titanium-depleted magnetite recrystallised in iron-bearing silicate minerals and left ilmenite behind. Host rocks were subsequently eroded and ilmenite was easily separated from less dense silicate minerals and concentrated into the ilmenite sand in the dynamic environment along the seashore. 

Our recent and historical work, comprising on- and offshore geological and geophysical surveys, photogrammetry, and petrographic and mineralogical analyses is helping industry to advance exploration projects focused on the placer deposits.

Magnetite and ilmenete

Exsolved titaniferous magnetite (BS-32) and totally recrystallised ilmenite in replaced titaniferous magnetite.

Troels F D Nielsen
Mapping and Mineral Resources