Staff profile
Professor Madeleine Humphreys
Professor
Affiliation | Telephone |
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Professor in the Department of Earth Sciences | +44 (0) 191 33 42343 |
Biography
My research is in igneous petrology, volcanology and magmatism, with a focus on understanding processes of magma storage, chemical evolution and migration within the crust using both natural materials and experimental approaches. My current research interests include (i) using crystal textures to understand and quantify magma solidification and the physical behaviour of crystal mushes, and (ii) volatiles in volcanic processes, including the timing of fluid exsolution and the enrichment and migration of metals in volcanic settings.
Current and recent research projects include:
- using crystal textures combined with apatite geochemistry to interpret crystal mush behaviour in the lead-up to big eruptions (ERC Consolidator; PI)
- using plagioclase crystal textures to understand mush processes in arc magmatic systems (NERC; PI)
- effects of sintering on transitions in volcanic eruptive behaviour (NERC; Co-I)
- defining speciation and structural environments for metals and volatiles complexes in silicate melts (in collaboration with Alex Iveson; Leverhulme Early Career Fellowship)
- using apatite volatile geochemistry to interpret the formation conditions for porphyry copper mineralising systems
- metal enrichment and extraction from granites
We have a very active volcanology-petrology group in Durham. Currently working in the group with me are: (i) Dr Amanda Lindoo, who is working on crystal shape in plagioclase, (ii) Dr David Colby, who is working on the behaviour of volatiles in apatite; and (iii) Dr Brenna Halverson, who is investigating porosity, permeability and crystal shape change during magma solidification.
Current PhD students include Annabelle Foster, who is working on sintering textures in obsidian (primary supervisor Fabian Wadsworth); Gemma Brown, who is working on apatite volatile geochemistry in the Canary islands; Katie Schofield, who is working on crystal textures and chemistry in plutonic rocks from the Adamello batholith, and Ella Richmond, who is investigating lithium enrichment and mobilisation in granites. I co-supervise Emily Jones (University of St Andrews, primary supervisor Will McCarthy) working on crystal mush properties at Illimaussaq, Greenland.
Current MScR students (2023-2024) are Rebecca Hughes (crystal textures and magma dynamics at Soufrière Hills volcano), Louis Chambers (zoned pumice falls in southern Tenerife, primary supervisor Rich Brown), and Will Nicholson (lithium and trace metal behaviour in the Metaketake pegmatites, NZ, primary supervisor Catriona Menzies).
Recent postdoctoral researchers include Dr Martin Mangler (now at University of Southampton), Dr Alex Iveson, now at PPNL (USA), and Dr Charline Lormand (now at University of Geneva). Recent graduate students include Dr Ceri Allgood (now at University of Lancaster), who worked on dyke propagation and flow, Dr Madeleine Stow, who worked on transition metal stable isotope fractionation in granites (primary supervisor Julie Prytulak); Dr Kris Sokól (St Andrews) who worked on fenite alteration around alkaline intrusions (primary supervisor Adrian Finch); and Eshbal Geifman (now at Trinity College, Dublin) who recently completed her MScR thesis on high-temperature plagioclase crystallisation experiments using a microscope-mounted heating stage.
I am always happy to hear from potential graduate students or post-docs interested in developing projects at Durham.
Esteem Indicators
- 2020: Associate Editor, Journal of Petrology:
- 2019: Wager Medal, IAVCEI:
- 2017: Editorial board member, Geology:
- 2012: Max Hey medal, Mineralogical Society of Great Britain:
- 2008: President's Award, Geological Society of London:
Publications
Chapter in book
- Edmonds, M., Humphreys, M., Hauri, E., Herd, R., Wadge, G., Rawson, H., Ledden, R., Plail, M., Barclay, J., Aiuppa, A., Christopher, T., Giudice, G., & Guida, R. (2014). Pre-eruptive vapour and its role in controlling eruption style and longevity at Soufriere Hills Volcano. In G. Wadge, R. Robertson, & B. Voight (Eds.), The eruption of Soufrière Hills Volcano, Montserrat from 2000 to 2010 (291-315). The Geological Society. https://doi.org/10.1144/m39.16
- Plail, M., Barclay, J., Humphreys, M., Edmonds, M., Herd, R., & Christopher, T. (2014). Characterization of mafic enclaves in the erupted products of Soufrière Hills Volcano, Montserrat, 2009 to 2010. In G. Wadge, R. Robertson, & B. Voight (Eds.), The eruption of Soufrière Hills Volcano, Montserrat from 2000 to 2010 (343-360). The Geological Society. https://doi.org/10.1144/m39.18
- Christopher, T., Humphreys, M., Barclay, J., Genareau, K., De Angelis, S., Plail, M., & Donovan, A. (2014). Petrological and geochemical variation during the Soufrière Hills eruption, 1995 to 2010. In G. Wadge, R. Robertson, & B. Voight (Eds.), The Eruption of Soufrière Hills Volcano, Montserrat from 2000 to 2010 (317-342). The Geological Society. https://doi.org/10.1144/m39.17
Conference Paper
Journal Article
- Sun, Y., Zhou, Q., Wang, R., & Humphreys, M. C. (2025). Magmatic initial and saturated water thresholds determine copper endowments: Insights from apatite F-Cl-OH compositions. Geoscience Frontiers, 16(1), Article 101962. https://doi.org/10.1016/j.gsf.2024.101962
- Stow, M. A., Prytulak, J., Humphreys, M. C., Hammond, S. J., & Nowell, G. M. (2024). Vanadium isotope fractionation during plutonic differentiation and implications for the isotopic composition of the upper continental crust. Earth and Planetary Science Letters, 643, Article 118825. https://doi.org/10.1016/j.epsl.2024.118825
- Paine, A. R., Baldini, J. U., Ünal-İmer, E., Wadsworth, F. B., Iveson, A. A., Humphreys, M. C., Brown, R. J., Müller, W., & Ottley, C. J. (2024). Abrupt climate change at the MIS 5/4 transition recorded in a speleothem from the Eastern Mediterranean. Quaternary Science Reviews, 339, Article 108841. https://doi.org/10.1016/j.quascirev.2024.108841
- Mangler, M. F., Humphreys, M. C. S., Iveson, A. A., Cooper, K. M., Clynne, M. A., Lindoo, A., Brooker, R. A., & Wadsworth, F. B. (2024). Crystal resorption as a driver for mush maturation: an experimental investigation. Journal of Petrology, 65(9), Article egae088. https://doi.org/10.1093/petrology/egae088
- Foster, A., Wadsworth, F. B., Tuffen, H., Unwin, H. E., & Humphreys, M. C. S. (2024). Evidence for the formation of silicic lava by pyroclast sintering. Nature Communications, 15(1), 5347. https://doi.org/10.1038/s41467-024-49601-6
- Lormand, C., Humphreys, M. C., Colby, D. J., Coumans, J. P., Chelle-Michou, C., & Li, W. (2024). Volatile budgets and evolution in porphyry-related magma systems, determined using apatite. Lithos, 480-481, Article 107623. https://doi.org/10.1016/j.lithos.2024.107623
- Allgood, C., Llewellin, E. W., Humphreys, M. C. S., Mathias, S. A., Brown, R. J., & Vye‐Brown, C. (2024). Banding in the Margins of Basaltic Dykes Indicates Pulsatory Propagation During Emplacement. Journal of Geophysical Research: Solid Earth, 129(4), Article e2023JB028007. https://doi.org/10.1029/2023jb028007
- Bretagne, E., Wadsworth, F. B., Vasseur, J., Humphreys, M. C., Dingwell, D. B., Dobson, K. J., Mangler, M. F., & Rooyakkers, S. M. (2023). The permeability of loose magma mush. Geology, 51(9), 829-832. https://doi.org/10.1130/g51133.1
- Mangler, M. F., Humphreys, M. C. S., Geifman, E., Iveson, A. A., Wadsworth, F. B., Brooker, R. A., Lindoo, A., & Hammond, K. (2023). Melt diffusion-moderated crystal growth and its effect on euhedral crystal shapes. Journal of Petrology, 64(8), https://doi.org/10.1093/petrology/egad054
- Iveson, A. A., Humphreys, M. C., Jenner, F. E., Kunz, B. E., Savov, I. P., De Hoog, J. C., Churikova, T. G., Gordeychik, B. N., Hammond, S. J., Plechov, P. Y., Blundy, J., & Agostini, S. (2022). Tracing Volatiles, Halogens, and Chalcophile Metals during Melt Evolution at the Tolbachik Monogenetic Field, Kamchatka. Journal of Petrology, 63(9), https://doi.org/10.1093/petrology/egac087
- Mangler, M. F., Humphreys, M. C., Wadsowrth, F. B., Iveson, A. A., & Higgins, M. D. (2022). Variation of plagioclase shape with size in intermediate magmas: a window into incipient plagioclase crystallisation. Contributions to Mineralogy and Petrology, 177(6), Article 64. https://doi.org/10.1007/s00410-022-01922-9
- Stow, M. A., Prytulak, J., Humphreys, M. C., & Nowell, G. M. (2022). Integrated Petrological and Fe-Zn Isotopic Modelling of Plutonic Differentiation. Geochimica et Cosmochimica Acta, 320, 366-391. https://doi.org/10.1016/j.gca.2021.12.018
- Cassidy, M., Iveson, A., Humphreys, M., Mather, T., Helo, C., Castro, J., Ruprecht, P., Pyle, D., & EIMF. (2022). Experimentally-derived F, Cl and Br fluid/melt partitioning of intermediate to silicic melts in magmatic systems. American Mineralogist, 107(10), 1825-1839. https://doi.org/10.2138/am-2022-8109
- Holness, M. B., Humphreys, M. C., Namur, O., Andersen, J., Tegner, C., & Nielsen, T. (2022). Crystal mush growth and collapse on a steep wall: the Marginal Border Series of the Skaergaard Intrusion, East Greenland. Journal of Petrology, 63(1), https://doi.org/10.1093/petrology/egab100
- Sokół, K., Finch, A. A., Hutchison, W., Cloutier, J., Borst, A. M., & Humphreys, M. C. (2022). Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas. Geology, 50(3), 305-310. https://doi.org/10.1130/g49471.1
- Humphreys, M. C., Smith, V. C., Coumans, J. P., Riker, J. M., Stock, M. J., de Hoog, J., & Brooker, R. A. (2021). Rapid pre-eruptive mush reorganisation and atmospheric volatile emissions from the 12.9 ka Laacher See eruption, determined using apatite. Earth and Planetary Science Letters, 576, Article 117198. https://doi.org/10.1016/j.epsl.2021.117198
- Iveson, A. A., Humphreys, M. C., Savov, I. P., de Hoog, J. C., Turner, S. J., Churikova, T. G., Macpherson, C. G., Mather, T. A., Gordeychik, B. N., Tomanikova, L., Agostini, S., Hammond, K., Pyle, D. M., & Cooper, G. F. (2021). Deciphering variable mantle sources and hydrous inputs to arc magmas in Kamchatka. Earth and Planetary Science Letters, 562, https://doi.org/10.1016/j.epsl.2021.116848
- Blundy, J., Melekhova, E., Ziberna, L., Humphreys, M. C., Cerantola, V., Brooker, R. A., McCammon, C. A., Pichavant, M., & Ulmer, P. (2020). Effect of redox on Fe–Mg–Mn exchange between olivine and melt and an oxybarometer for basalts. Contributions to Mineralogy and Petrology, 175(11), Article 103. https://doi.org/10.1007/s00410-020-01736-7
- Coumans, J., Llewellin, E., Wadsworth, F., Humphreys, M., Mathias, S., Yelverton, B., & Gardner, J. (2020). An experimentally validated numerical model for bubble growth in magma. Journal of Volcanology and Geothermal Research, 402, Article 107002. https://doi.org/10.1016/j.jvolgeores.2020.107002
- Coumans, J. P., Llewellin, E. W., Humphreys, M. C., Nowak, M., Brooker, R. A., Mathias, S. A., & McIntosh, I. M. (2020). An experimentally-validated numerical model of diffusion and speciation of water in rhyolitic silicate melt. Geochimica et Cosmochimica Acta, 276, 219-238. https://doi.org/10.1016/j.gca.2020.02.026
- Cooper, G. F., Blundy, J. D., Macpherson, C. G., Humphreys, M. C., & Davidson, J. P. (2019). Evidence from plutonic xenoliths for magma differentiation, mixing and storage in a volatile-rich crystal mush beneath St. Eustatius, Lesser Antilles. Contributions to Mineralogy and Petrology, 174(5), Article 39. https://doi.org/10.1007/s00410-019-1576-4
- Humphreys, M., Zhang, J., Cooper, G., Macpherson, C., & Ottley, C. (2019). Identifying the ingredients of hydrous arc magmas: insights from Mt Lamington, Papua New Guinea. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 377(2139), Article 20180018. https://doi.org/10.1098/rsta.2018.0018
- Humphreys, M. C., Cooper, G. F., Zhang, J., Loewen, M., Kent, A. J., Macpherson, C. G., & Davidson, J. P. (2019). Unravelling the complexity of magma plumbing at Mount St. Helens: a new trace element partitioning scheme for amphibole. Contributions to Mineralogy and Petrology, 174(1), Article 9. https://doi.org/10.1007/s00410-018-1543-5
- Stock, M. J., Humphreys, M. C., Smith, V. C., Isaia, R., Brooker, R. A., & Pyle, D. M. (2018). Tracking volatile behaviour in sub-volcanic plumbing systems using apatite and glass: insights into pre-eruptive processes at Campi Flegrei, Italy. Journal of Petrology, 59(12), 2463-2492. https://doi.org/10.1093/petrology/egy020
- Namur, O., & Humphreys, M. C. (2018). Trace element constraints on the differentiation and crystal mush solidification in the Skaergaard intrusion, Greenland. Journal of Petrology, 59(3), 387-418. https://doi.org/10.1093/petrology/egy032
- Plail, M., Edmonds, M., Woods, A., Barclay, J., Humphreys, M. C., Herd, R. A., & Christopher, T. (2018). Mafic enclaves record syn-eruptive basalt intrusion and mixing. Earth and Planetary Science Letters, 484, 30-40. https://doi.org/10.1016/j.epsl.2017.11.033
- Riker, J., Humphreys, M., Brooker, R., de Hoog, J., & EIMF. (2018). First measurements of OH-C exchange and temperature-dependent partitioning of OH and halogens in the system apatite - silicate melt. American Mineralogist, 103(2), 260-270. https://doi.org/10.2138/am-2018-6187ccby
- Zhang, J., Humphreys, M., Cooper, G., Davidson, J., & Macpherson, C. (2017). Magma mush chemistry at subduction zones, revealed by new melt major element inversion from calcic amphiboles. American Mineralogist, 102(6), 1353-1367. https://doi.org/10.2138/am-2017-5928
- Edmonds, M., Kohn, S., Hauri, E., Humphreys, M., & Cassidy, M. (2016). Extensive, water-rich magma reservoir beneath southern Montserrat. Lithos, 252-253, 216-233. https://doi.org/10.1016/j.lithos.2016.02.026
- Humphreys, M., Edmonds, M., & Kloecking, M. (2016). The validity of plagioclase-melt geothermometry for degassing-driven magma crystallization. American Mineralogist, 101(4), 769-779. https://doi.org/10.2138/am-2016-5314
- Stock, M., Humphreys, M., Smith, V., Isaia, R., & Pyle, D. (2016). Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions. Nature Geoscience, 9(3), 249-254. https://doi.org/10.1038/ngeo2639
- Zhang, J., Davidson, J., Humphreys, M., Macpherson, C., & Neill, I. (2015). Magmatic Enclaves and Andesitic Lavas from Mt. Lamington, Papua New Guinea: Implications for Recycling of Earlier-fractionated Minerals through Magma Recharge. Journal of Petrology, 56(11), 2223-2256. https://doi.org/10.1093/petrology/egv071
- Scott, J., Humphreys, M., Mather, T., Pyle, D., & Stock, M. (2015). Insights into the behaviour of S, F, and Cl at Santiaguito Volcano, Guatemala, from apatite and glass. Lithos, 232, 375-394. https://doi.org/10.1016/j.lithos.2015.07.004
- Humphreys, M. C., Edmonds, M., Christopher, T., & Hards, V. (2015). Discussion on ‘Magma storage region processes of the Soufrière Hills Volcano, Montserrat’, Geological Society, London, Memoirs, 39, 361-381. Journal of the Geological Society, 172(4), 533-539. https://doi.org/10.1144/jgs2014-140
- Humphreys, M., Brooker, R., Fraser, D., Burgisser, A., Mangan, M., & McCammon, C. (2015). Coupled interactions between volatile activity and Fe oxidation state during arc crustal processes. Journal of Petrology, 56(4), 795-814. https://doi.org/10.1093/petrology/egv017
- Edmonds, M., Brett, A., Herd, R., Humphreys, M., & Woods, A. (2015). Magnetite-bubble aggregates at mixing interfaces in andesite magma bodies. Geological Society Special Publications, 410(1), 95-121. https://doi.org/10.1144/sp410.7
- Stock, M., Humphreys, M., Smith, V., Johnson, R., Pyle, D., & EIMF. (2015). New constraints on electron-beam induced halogen migration in apatite. American Mineralogist, 100(1), 281-293. https://doi.org/10.2138/am-2015-4949
- Melekhova, E., Blundy, J., Robertson, R., & Humphreys, M. (2015). Experimental evidence for polybaric differentiation of primitive arc basalt beneath St. Vincent, Lesser Antilles. Journal of Petrology, 56(1), 161-192. https://doi.org/10.1093/petrology/egu074
- McIntosh, I., Llewellin, E., Humphreys, M., Nichols, A., Burgisser, A., Schipper, C., & Larsen, J. (2014). Distribution of dissolved water in magmatic glass records growth and resorption of bubbles. Earth and Planetary Science Letters, 401, 1-11. https://doi.org/10.1016/j.epsl.2014.05.037
- Bufe, N. A., Holness, M. B., & Humphreys, M. C. (2014). Contact metamorphism of Precambrian gneiss by the Skaergaard Intrusion. Journal of Petrology, 55(8), 1595-1617. https://doi.org/10.1093/petrology/egu035
- Namur, O., Humphreys, M. C., & Holness, M. B. (2014). Crystallization of interstitial liquid and latent heat buffering in solidifying gabbros: Skaergaard Intrusion, Greenland. Journal of Petrology, 55(7), 1389-1427. https://doi.org/10.1093/petrology/egu028
- Stamper, C., Melekhova, E., Blundy, J., Arculus, R., Humphreys, M., & Brooker, R. (2014). Oxidised phase relations of a primitive basalt from Grenada, Lesser Antilles. Contributions to Mineralogy and Petrology, 167(1), https://doi.org/10.1007/s00410-013-0954-6
- Plail, M., Edmonds, M., Humphreys, M., Barclay, J., & Herd, R. (2014). Geochemical evidence for relict degassing pathways preserved in andesite. Earth and Planetary Science Letters, 386, 21-33. https://doi.org/10.1016/j.epsl.2013.10.044
- Namur, O., Humphreys, M. C., & Holness, M. B. (2013). Lateral Reactive Infiltration in a Vertical Gabbroic Crystal Mush, Skaergaard Intrusion, East Greenland. Journal of Petrology, 54(5), 985-1016. https://doi.org/10.1093/petrology/egt003
- Humphreys, M., Edmonds, M., Plail, M., Barclay, J., Parkes, D., & Christopher, T. (2013). A new method to quantify the real supply of mafic components to a hybrid andesite. Contributions to Mineralogy and Petrology, 165(1), 191-215. https://doi.org/10.1007/s00410-012-0805-x
- Holness, M., Humphreys, M., Sides, R., Helz, R., & Tegner, C. (2012). Toward an understanding of disequilibrium dihedral angles in mafic rocks. Journal of Geophysical Research, 117(B6), https://doi.org/10.1029/2011jb008902
- Holness, M., Stripp, G., Humphreys, M., Veksler, I., Nielsen, T., & Tegner, C. (2011). Silicate Liquid Immiscibility within the Crystal Mush: Late-stage Magmatic Microstructures in the Skaergaard Intrusion, East Greenland. Journal of Petrology, 52(1), 175-222. https://doi.org/10.1093/petrology/egq077
- Humphreys, M. (2011). Silicate liquid immiscibility within the crystal mush: Evidence from Ti in plagioclase from the Skaergaard Intrusion. Journal of Petrology, 52(1), 147-174. https://doi.org/10.1093/petrology/egq076
- Edmonds, M., Aiuppa, A., Humphreys, M., Moretti, R., Giudice, G., Martin, R., Herd, R., & Christopher, T. (2010). Excess volatiles supplied by mingling of mafic magma at an andesite arc volcano. Geochemistry, Geophysics, Geosystems, 11, Article Q04005. https://doi.org/10.1029/2009gc002781
- Humphreys, M., Edmonds, M., Christopher, T., & Hards, V. (2010). Magma hybridisation and diffusive exchange recorded in heterogeneous glasses from Soufriere Hills Volcano, Montserrat. Geophysical Research Letters, 37, Article L00E06. https://doi.org/10.1029/2009gl041926
- Christopher, T., Edmonds, M., Humphreys, M., & Herd, R. (2010). Volcanic gas emissions from Soufriere Hills Volcano, Montserrat 1995-2009, with implications for mafic magma supply and degassing. Geophysical Research Letters, 37(19), Article L00E04. https://doi.org/10.1029/2009gl041325
- Humphreys, M., & Holness, M. (2010). Melt-rich segregations in the Skaergaard Marginal Border Series: Tearing of a vertical silicate mush. Lithos, 119(3-4), 181-192. https://doi.org/10.1016/j.lithos.2010.06.006
- Humphreys, M. (2009). Chemical evolution of intercumulus liquid, as recorded in plagioclase overgrowth rims from the Skaergaard Intrusion. Journal of Petrology, 50(1), 127-145. https://doi.org/10.1093/petrology/egn076
- Humphreys, M., Christoper, T., & Hards, V. (2009). Microlite transfer by disaggregation of mafic inclusions following magma mixing at Soufrière Hills Volcano, Montserrat. Contributions to Mineralogy and Petrology, 157(5), 609-624. https://doi.org/10.1007/s00410-008-0356-3
- Humphreys, M., Edmonds, M., Christopher, T., & Hards, V. (2009). Chlorine variations in the magma of Soufriere Hills Volcano, Montserrat: Insights from Cl in hornblende and melt inclusions. Geochimica et Cosmochimica Acta, 73(19), 5693-5708. https://doi.org/10.1016/j.gca.2009.06.014
- Sparks, R., Folkes, C., Humphreys, M., Barfod, D., Clavero, J., Sunagua, M., McNutt, S., & Pritchard, M. (2008). Uturuncu volcano, Bolivia: Volcanic unrest due to mid-crustal magma intrusion. American journal of science (1880), 308(6), 727-769. https://doi.org/10.2475/06.2008.01
- Humphreys., M., Menand, T., Blundy, J., & Klimm, K. (2008). Magma ascent rates in explosive eruptions:Constraints from H2O diffusion in melt inclusions. Earth and Planetary Science Letters, 270(1-2), 25-40. https://doi.org/10.1016/j.epsl.2008.02.041
- Humphreys, M., Blundy, J., & Sparks, R. (2007). Shallow-level decompression crystallisation and deep magma supply at Shiveluch Volcano. Contributions to Mineralogy and Petrology, 155(1), 45-61. https://doi.org/10.1007/s00410-007-0223-7
- Humphreys, M., Blundy, J., & Sparks, R. (2006). Magma evolution and open-system processes at Shiveluch Volcano: Insights from phenocryst zoning. Journal of Petrology, 47(12), 2303-2334. https://doi.org/10.1093/petrology/egl045
- Humphreys, M., Kearns, S., & Blundy, J. (2006). SIMS investigation of electron-beam damage to hydrous, rhyolitic glasses: Implications for melt inclusion analysis. American Mineralogist, 91(4), 667-679. https://doi.org/10.2138/am.2006.1936
- Dirksen, O., Humphreys, M., Pletchov, P., Melnik, O., Demyanchuk, Y., Sparks, R., & Mahony, S. (2006). The 2001-2004 dome-forming eruption of Shiveluch volcano, Kamchatka: Observation, petrological investigation and numerical modelling. Journal of Volcanology and Geothermal Research, 155(3-4), 201-226
- Blundy, J., Cashman, K., & Humphreys, M. (2006). Magma heating by decompression-driven crystallization beneath andesite volcanoes. Nature, 443(7107), 76-80. https://doi.org/10.1038/nature05100
- Holness, M., & Humphreys, M. (2003). The Traigh Bhan na Sgurra Sill, Isle of Mull: Flow localization in a major magma conduit. Journal of Petrology, 44(11), 1961-1976. https://doi.org/10.1093/petrology/egg066