The Origin of Pentlandite Loops in Magmatic Sulfide Ores – [publication]

Pentlandite is the dominant Ni-hosting ore mineral in most magmatic sulfide deposits and has conventionally been interpreted as being entirely generated by solid-state exsolution from the high-temperature monosulfide solid solution (MSS) (Fe,Ni)_1–xS. This process gives rise to the development of loops of pentlandite surrounding pyrrhotite grains. Recently it has been recognized that not all pentlandite forms by exsolution. Some may form as the result of peritectic reaction between early formed MSS and residual Ni-Cu–rich sulfide liquid during differentiation of the sulfide melt, such that at least some loop textures may be genuinely magmatic in origin. The spectacular loop textures in the massive sulfide ores at Nova-Bollinger are the result of emplacement of sulfide liquids into country rocks already within the melting temperature range of the sulfides.

Read more about the formation of these common sulfide textures in the full article below:

Stephen J. Barnes, Valentina Taranovic, Louise E. Schoneveld, Eduardo T. Mansur, Margaux Le Vaillant, Sarah Dare, Sebastian Staude, Noreen J. Evans, Daryl Blanks; The Occurrence and Origin of Pentlandite-Chalcopyrite-Pyrrhotite Loop Textures in Magmatic Ni-Cu Sulfide Ores. Economic Geology 2020;; 115 (8): 1777–1798. doi: https://doi.org/10.5382/econgeo.4757