Tracing the fluid evolution of the Kiruna iron oxide apatite deposits using zircon, monazite, and whole rock trace elements and isotopic studies

Stark contrasts are visible between the ore (depleted mantle influence) and host rocks (crustal influence) in the whole rock Lu-Hf and Sm-Nd data. The depleted mantle signature of the ore could be related to the Kiruna greenstone group as a potential source region for the iron. The Sm-Nd isotopic composition of monazite from the ore shows a crustal influence, and indicates that the younger event has not disturbed the whole rock Sm-Nd signature of the ore. The hydrothermal nature of the ore zircon grains and the isotopic signatures point to a hydrothermal influence on the ore formation, with a high temperature magmatic fluid related to the intrusions as most likely heat and fluid source.