Research

The physico-chemical processes that operate at depth in transcrustal magma systems have implications for both volcanism at the Earth’s surface and the formation of critical mineral deposits in the crust. In subduction zones, these processes are poorly constrained, particularly for mantle-derived melts that have experienced little fractionation. The investigation of ancient, exhumed intrusions allows chemical data to be placed in spatial and textural context, providing information on both the architecture and physico-chemical evolution of magmas as they crystallize and evolve. My PhD research is contributing to the developing framework for transcrustal magma systems in subduction zones by investigating the Late Triassic Tulameen Alaskan-type intrusion in the Quesnel terrane of south-central British Columbia through a combined field, petrographic, and geochemical approach.

Teaching

EOSC 223 · Introduction to Geological Map Interpretation & Field Techniques

EOSC 328 · Field Geology

EOSC 220 · Introductory Mineralogy

Education

  • PhD (Candidate) in Geological Sciences: University of British Columbia. Supervisors: Dr. James Scoates; 2021-present
  • BSc in Geology: University of British Columbia

Journal Publications

6.                           Goan, I.R., Scoates, J.S., Milidragovic, D., Spence, D.W., Nott, J.A., and Nixon, G.T. (submitted)Magnetite in arc magmas: Petrochemistry of magnetite from Alaskan-type ultramafic–mafic intrusions in the Canadian Cordillera. Lithos. Estimated publication year: 2026

5.                           Milidragovic, D., Spence, D.W. (2026) Degassing-driven ascent and explosive eruption of picritic slurries in arc settings. Contributions to Mineralogy and Petrology, 181, 10. https://doi.org/10.1007/s00410-025-02292-8

4.                           Nixon, G.T., Manor, M.J., Scoates, J.S., Spence, D.W., Milidragovic, D. (2024) Mineralogical constraints on magma storage conditions in ultramafic arc cumulates and the nature and role of cryptic fugitive melts: Tulameen Alaskan-type intrusion, North American Cordillera. Contributions to Mineralogy and Petrology, 179, 103. https://doi.org/10.1007/s00410-024-02181-6

3.                           Spence, D.W., Scoates, J.S., Milidragovic, D., Nott, J.A., Nixon, G.T. (2024) Olivine in ultramafic rocks from the Polaris Alaskan-type intrusion: A geochemical record of open-system crystallization, diffusional re-equilibration, mantle source, and redox conditions in primitive arc magmas. Lithos, 474–475. https://doi.org/10.1016/j.lithos.2024.107578

2.                           Milidragovic, D., Nott, J.A., Spence, D.W., Schumann, D., Scoates, J.S., Nixon, G.T., Stern, R.A. (2023) Sulfate recycling at subduction zones indicated by sulfur isotope systematics of Mesozoic ultramafic island arc cumulates in the North American Cordillera. Earth and Planetary Science Letters, 620, 118337. https://doi.org/10.1016/j.epsl.2023.118337

1.                           Milidragovic, D., Nixon, G.T., Scoates, J.S., Nott, J.A., Spence, D.W. (2021) Redox-controlled chalcophile element geochemistry of the Polaris Alaskan-type mafic-ultramafic complex, British Columbia, Canada. The Canadian Mineralogist, 59, 1627–1660. https://doi.org/10.3749/canmin.2100006

 

Government Reports

4.                           Goan, I.R., Scoates, J.S., Milidragovic, D., Spence, D.W., Nott, J.A., and Nixon, G.T. (2026) Magnetite petrochemistry in Alaskan-type ultramafic-mafic intrusions of British Columbia: Controls of magmatic, mineralization, subsolidus, and hydrothermal processes. Geofile 2026-04 (poster), British Columbia Ministry of Mining and Critical Minerals, British Columbia Geological Survey (also presented at Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada).https://cmscontent.nrs.gov.bc.ca/geoscience/PublicationCatalogue/GeoFile/BCGS_GF2026-04.pdf

 

3.                  Spence, D.W., Scoates, J.S., Goan, I.R., Nott, J.A., Nixon, G.T., Milidragovic, D. (2024) Dynamic magmatic processes recorded in the Tulameen ultramafic-mafic Alaskan-type intrusion from outcrop-scale structures and mineral-scale textures. Geofile 2024-14 (poster), British Columbia Ministry of Energy, Mines and Low Carbon Innovation, British Columbia Geological Survey (also presented at Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada). https://cmscontent.nrs.gov.bc.ca/geoscience/PublicationCatalogue/GeoFile/BCGS_GF2024-14.pdf

2.                  Spence, D.W., Crawford, H., Scoates, J.S., Nott, J.A., Nixon, G.T., Milidragovic, D. (2022) Mapping ultramafic cumulates at the Tulameen ultramafic-mafic Alaskan-type intrusion, south-central British Columbia, aided by remotely piloted aircraft system photogrammetry. Geological Fieldwork, British Columbia Ministry of Energy, Mines and Low Carbon Innovation, British Columbia Geological Survey Paper 2022-01, 103-122. https://cmscontent.nrs.gov.bc.ca/geoscience/PublicationCatalogue/Paper/BCGS_P2022-01-07_Spence.pdf

1.                           Nixon, G.T., Scoates, J.S., Milidragovic, D., Nott, J., Manor, M.J., Spence, D.W., Kjarsgaard, I.M. (2021) Cu-PGE vs Cr-PGE mineralization in Alaskan-type mafic-ultramafic intrusions. Geofile 2021-07(poster), British Columbia Ministry of Energy, Mines and Low Carbon Innovation, British Columbia Geological Survey (also as a poster at Association of Mineral Exploration (AME) Roundup Conference, Online), https://cmscontent.nrs.gov.bc.ca/geoscience/PublicationCatalogue/GeoFile/BCGS_GF2021-07.pdf

 

Conference Presentations with Abstract                  

21.                        Spence, D.W., Scoates, J.S., Milidragovic, D., Nixon, G.T. (2026) Sr and Y in clinopyroxene as indicators for magma-mush interactions in the ultramafic-mafic Tulameen Alaskan-type intrusion, North American Cordillera. Goldschmidt Conference Montreal, Canada (poster and presentation).

20.                        Milidragovic, D., Spence, D.W. (2025) Volatile-driven melting, ascent, and explosive eruption of picritic slurries in arc settings. Goldschmidt Conference Montreal, Canada (poster and presentation).

19.                        Spence, D.W., Scoates, J.S., Milidragovic, D., Nixon, G.T. (2025) Insights into arc mantle sources and crustal differentiation from olivine and clinopyroxene chemistry in ultramafic rocks of the Tulameen Alaskan-type intrusion. American Geophysical Union (AGU) Annual Meeting, New Orleans, USA (presentation).

18.                        Milidragovic, D., Spence, D.W. (2025) Late Triassic Kamloops picrites, southwestern British Columbia: Degassing-driven ascent and explosive eruption of picritic slurries in arc settings. Cordilleran Tectonic Workshop Vancouver, Canada (presentation).

17.                        Spence, D.W., Scoates, J.S., Goan, I.R., Nott, J.A., Nixon, G.T., Milidragovic, D. (2025) Progress on a large-scale geological map of intermingled ultramafic cumulates in the Tulameen Alaskan-type intrusion, south-central British Columbia: Integrating modern field techniques to inform magmatic processes. Association of Mineral Exploration (AME) Roundup Conference, Vancouver, Canada (poster and presentation).

16.                        Goan, I.R., Scoates, J.S., Milidragovic, D., Spence, D.W., Nott, J.A., Nixon, G.T. (2025) Magnetite chemistry in arc rocks: Insights from Alaskan-type ultramafic-mafic intrusions in the Canadian Cordillera.Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster).

15.                        Spence, D.W., Scoates, J.S., Milidragovic, D., Nixon, G.T. (2024) Clinopyroxene from the Tulameen Alaskan-type ultramafic-mafic Intrusion in the North American Cordillera records mid-crustal magmatic conditions in a Mesozoic island arc. Geological Society of America (GSA) Connects, Anaheim, USA (presentation). https://gsa.confex.com/gsa/2024AM/meetingapp.cgi/Paper/402479

14.                        Goan, I.R., Scoates, J.S., Milidragovic, D., Spence, D.W., Nott, J.A., Nixon, G.T. (2024) Magnetite trace element chemistry in arc rocks: A perspective from Alaskan-type ultramafic-mafic intrusions within the Canadian Cordillera. Geological Society of America (GSA) Connects, Anaheim, USA (poster). https://gsa.confex.com/gsa/2024AM/meetingapp.cgi/Paper/401278

13.                        Milidragovic, D., Nixon, G.T., Spence, D.W., Nott, J.A., Goan, I.R., Scoates, J.S. (2024) Primitive arc magmatism and the development of magmatic Ni-Cu-PGE mineralization in Alaskan-type ultramafic-mafic intrusions. International Ni-Cu Symposium, Thunder Bay, Canada (presentation).

12.                        Goan, I.R., Scoates, J.S., Milidragovic, D., Spence, D.W., Nott, J.A., Moerhuis, N., Nixon, G.T. (2024) A microanalytical study of magnetite within Alaskan-type ultramafic-mafic intrusions in British Columbia. Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster and presentation).

11.                        Scoates, J.S., Hickey, K.A., Moerhuis, N., Spence, D.W., Steiner, A.P., Saylor, J.E. (2023) Geological mapping at field school in the virtual environment. American Geophysical Union (AGU) Fall Meeting, San Francisco, USA (poster). https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1297743

10.                        Spence, D.W., Scoates, J.S., Goan, I., Nott, J.A., Nixon, G.T., Milidragovic, D. (2023) LiDAR-, magnetic susceptibility-, and pXRF-assisted mapping at the Tulameen ultramafic-mafic Alaskan-type intrusion. Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster).

9.                           Goan, I., Scoates, J.S., Moerhuis, N., Spence, D.W., Nott, J.A., Webb, R., Milidragovic, D., Nixon, G.T. (2023) An overview of petrological and geochemical investigations of Fe-Ti oxides within Alaskan-type ultramafic-mafic intrusions in British Columbia. Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster).

8.                           Webb, R., Moerhuis, N., Scoates, J.S., Spence, D.W., Nott, J.A., Goan, I., Milidragovic, D., Nixon, G.T. (2023) Chromite in the Polaris Alaskan-type ultramafic-mafic intrusion of British Columbia: Preliminary petrochemical results. Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster).

7.                           Milidragovic, D., Nott, J.A., Spence, D.W., Scoates, J.S., Stern, R.A. (2022) Sulphur isotope systematics of island arc cumulates: Alaskan-type Polaris intrusion, North American Cordillera. American Geophysical Union (AGU) Annual Meeting, Chicago, USA (presentation). https://agu.confex.com/agu/fm22/meetingapp.cgi/Paper/1077011

6.                           Spence, D.W., Scoates, J.S., Nott, J.A., Milidragovic, D., Nixon, G.T. (2022) Olivine in primitive arc magmas from the Polaris Alaskan-type intrusion in the North American Cordillera. Goldschmidt Conference, Honolulu, USA (poster and presentation). https://doi.org/10.46427/gold2022.11305

5.                           Nott, J.A., Scoates, J.S., Milidragovic, D., Nixon, G.T. Spence, D.W. (2022) Primitive arc magma conduits from the zircon petrochronology perspective in the Polaris Alaskan-type intrusion, North American Cordillera. Goldschmidt Conference, Honolulu, USA (poster and presentation). https://doi.org/10.46427/gold2022.11788

4.                           Spence, D.W., Crawford, H., Scoates, J.S., Nott, J.A., Nixon, G.T., Milidragovic, D. (2022) Mapping ultramafic cumulates at the Tulameen ultramafic-mafic Alaskan-type intrusion, south-central British Columbia. Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster and presentation).

3.                           Milidragovic, D., Nixon, G.T., Scoates, J.S., Nott, J., Spence, D.W. (2021) Petrological controls on PGE mineralization in Alaskan-type intrusions. Association of Mineral Exploration (AME) Roundup Conference, Online (poster).

2.                           Milidragovic, D., Nixon, G.T., Scoates, J.S., Nott, J., Spence, D.W. (2020) Redox controls on Cu-PGE-Au mineralization in the Polaris Alaskan- type intrusion, north-central British Columbia. Geological Society of America (GSA) Abstracts with Programs. https://doi.org/10.1130/abs/2020AM-357971

1.                           Spence, D., Scoates, J.S., Milidragovic, D., Nott, J.A. (2020) Olivine in the Polaris Alaskan-type intrusion of north-central British Columbia: Petrographic variation and preliminary geochemistry. Association of Mineral Exploration (AME) Roundup Conference Vancouver, Canada (poster).