Tom Ver Hoeve
University of British Columbia
Mafic layered intrusions (MLI) occur in the Earth’s crust on all continents spanning geologic time and are host to the planet’s most significant known deposits of platinum group elements (PGE), chromium, and vanadium. Tiny accessory minerals like zircon (ZrSiO4) and rutile (TiO2) can be recovered from these intrusions to reveal information about their parental magmas. While widely known for its applications in U-Th-Pb geochronology, zircon incorporates other trace elements (e.g. U, Th, Ti, Hf, Y+REE, Nb, Ta, Li) into its crystal structure that provide a geochemical fingerprint of chemical and thermal evolution of the melt.
I became interested in mafic layered intrusions through my honours thesis under Dr. James Scoates during my BSc in Honours Geological Sciences at UBC (graduated 2013). My thesis looked at the peculiar geochemistry of altered metamict zircon from a suite of granophyres from the Stillwater Complex, a massive MLI in southwestern Montana. I used the spatial capabilities of laser ablation ICP-MS (LA-ICP-MS) to document the mobility of trace elements in these metamict zircon during hydrothermal alteration.
At the end of my undergraduate thesis, with a budding interest in zircon, laser ablation, and layered intrusions, I was presented with an opportunity to embark on a new project on the Bushveld Complex in South Africa, the world’s largest MLI. This project, under the supervision of Dr. James Scoates and Dr. Dominique Weis, analyzes the trace element systematics of zircon and rutile spanning the 8-km thick intrusion using LA-ICP-MS and aims to develop a better concept of the magmatic evolution of the parental magmas to the Bushveld Complex.