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Professor Madeleine Humphreys' Outputs (63)

Magmatic initial and saturated water thresholds determine copper endowments: Insights from apatite F-Cl-OH compositions (2024)
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

Magmatic volatiles (H2O, F, Cl), especially water, are critical in the formation of porphyry copper deposit, for its significance as a carrier for metals. However, accurately quantifying the water contents of deep ore-forming magma remain a challenge... Read More about Magmatic initial and saturated water thresholds determine copper endowments: Insights from apatite F-Cl-OH compositions.

Crystal resorption as a driver for mush maturation: an experimental investigation (2024)
Journal Article
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

The thermal state of a magma reservoir controls its physical and rheological properties: at storage temperatures close to the liquidus, magmas are dominated by melt and therefore mobile, while at lower temperatures, magmas are stored as a rheological... Read More about Crystal resorption as a driver for mush maturation: an experimental investigation.

Vanadium isotope fractionation during plutonic differentiation and implications for the isotopic composition of the upper continental crust (2024)
Journal Article
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

The analysis of emerging stable isotopic systems in clastic sedimentary rocks is increasingly used to determine the average composition of the upper continental crust through geological time. Any temporal variations can then be linked to global-scale... Read More about Vanadium isotope fractionation during plutonic differentiation and implications for the isotopic composition of the upper continental crust.

Abrupt climate change at the MIS 5/4 transition recorded in a speleothem from the Eastern Mediterranean (2024)
Journal Article
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

The marine isotope stage (MIS) 5a to 4 transition (∼74 ka) was associated with rapid ice sheet expansion, declining moisture availability globally, and significant upheaval of terrestrial ecosystems across the northern hemisphere. Here, we present pr... Read More about Abrupt climate change at the MIS 5/4 transition recorded in a speleothem from the Eastern Mediterranean.

Evidence for the formation of silicic lava by pyroclast sintering (2024)
Journal Article
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

Silicic lavas can be produced by the sintering of pyroclasts in the volcanic sub-surface, and then advected out of the vent. Here, we provide evidence for this mechanism preserved in the exposed post-glacial remnants of a silicic volcanic conduit at... Read More about Evidence for the formation of silicic lava by pyroclast sintering.

Volatile budgets and evolution in porphyry-related magma systems, determined using apatite (2024)
Journal Article
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

Volatile-bearing minerals, such as apatite, Ca5(PO4)3(OH,F,Cl), can record changes in dissolved magmatic volatile species during differentiation and, unlike melt inclusions, are sensitive to the presence of an exsolved fluid phase. Populations of apa... Read More about Volatile budgets and evolution in porphyry-related magma systems, determined using apatite.

Banding in the Margins of Basaltic Dykes Indicates Pulsatory Propagation During Emplacement (2024)
Journal Article
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

Basaltic fissure eruptions, which are the most common type of eruption on Earth, are fed by dykes which mediate magma transport through the crust. Dyke propagation processes are important because they determine the geometry of the transport pathway a... Read More about Banding in the Margins of Basaltic Dykes Indicates Pulsatory Propagation During Emplacement.

Melt diffusion-moderated crystal growth and its effect on euhedral crystal shapes (2023)
Journal Article
Mangler, M. F., Humphreys, M. C. S., Geifman, E., Iveson, A. A., Wadsworth, F. B., Brooker, R. 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

Crystal growth is often described as either interface-controlled or diffusion-controlled. Here, we study crystal growth in an intermediate scenario where reaction rates at the crystal-melt interface are similar to the rates of diffusive transport of... Read More about Melt diffusion-moderated crystal growth and its effect on euhedral crystal shapes.

The permeability of loose magma mush (2023)
Journal Article
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

Models for the evolution of magma mush zones are of fundamental importance for understanding magma storage, differentiation in the crust, and melt extraction processes that prime eruptions. These models require calculations of the permeability of the... Read More about The permeability of loose magma mush.

Tracing Volatiles, Halogens, and Chalcophile Metals during Melt Evolution at the Tolbachik Monogenetic Field, Kamchatka (2022)
Journal Article
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

Melt storage and supply beneath arc volcanoes may be distributed between a central stratovolcano and wider fields of monogenetic cones, indicating complex shallow plumbing systems. However, the impact of such spatially variable magma storage conditio... Read More about Tracing Volatiles, Halogens, and Chalcophile Metals during Melt Evolution at the Tolbachik Monogenetic Field, Kamchatka.

Variation of plagioclase shape with size in intermediate magmas: a window into incipient plagioclase crystallisation (2022)
Journal Article
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

Volcanic rocks commonly display complex textures acquired both in the magma reservoir and during ascent to the surface. While variations in mineral compositions, sizes and number densities are routinely analysed to reconstruct pre-eruptive magmatic h... Read More about Variation of plagioclase shape with size in intermediate magmas: a window into incipient plagioclase crystallisation.

Integrated Petrological and Fe-Zn Isotopic Modelling of Plutonic Differentiation (2021)
Journal Article
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

The upper continental crust is formed from chemically diverse granitic plutons. Active debate surrounds the range of physical conditions (P-T-X-fO2) and differentiation processes which occur in mush bodies that solidify to form plutons. Transition me... Read More about Integrated Petrological and Fe-Zn Isotopic Modelling of Plutonic Differentiation.

Crystal mush growth and collapse on a steep wall: the Marginal Border Series of the Skaergaard Intrusion, East Greenland (2021)
Journal Article
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

The Skaergaard Intrusion of East Greenland solidified as a closed system, with the development of progressively more fractionated material at the roof, floor and vertical walls of the magma chamber. We argue, using field observations of the exposed w... Read More about Crystal mush growth and collapse on a steep wall: the Marginal Border Series of the Skaergaard Intrusion, East Greenland.

Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas (2021)
Journal Article
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

Alkaline igneous rocks host many global high-field-strength element (HFSE) and rare-earth element (REE) deposits. While HFSEs are commonly assumed to be immobile in hydrothermal systems, transport by late-stage hydrothermal fluids associated with alk... Read More about Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas.

Rapid pre-eruptive mush reorganisation and atmospheric volatile emissions from the 12.9 ka Laacher See eruption, determined using apatite (2021)
Journal Article
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

Magma is commonly thought to be stored as a crystal-rich mush within vertically extensive, crustal storage regions. A key unknown is how to remobilise and erupt such crystal-rich material, and whether the growth of gas bubbles within the mush could p... Read More about Rapid pre-eruptive mush reorganisation and atmospheric volatile emissions from the 12.9 ka Laacher See eruption, determined using apatite.

Deciphering variable mantle sources and hydrous inputs to arc magmas in Kamchatka (2021)
Journal Article
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

The chemistry of primitive arc rocks provides a window into compositional variability in the mantle wedge, as well as slab-derived inputs to subduction-related magmatism. However, in the long-term cycling of elements between Earth's internal and exte... Read More about Deciphering variable mantle sources and hydrous inputs to arc magmas in Kamchatka.

Effect of redox on Fe–Mg–Mn exchange between olivine and melt and an oxybarometer for basalts (2020)
Journal Article
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

The Fe–Mg exchange coefficient between olivine (ol) and melt (m), defined as KdFeT −Mg = (Feol/Fem)·(Mgm/Mgol), with all FeT expressed as Fe2+, is one of the most widely used parameters in petrology. We explore the effect of redox conditions on KdFeT... Read More about Effect of redox on Fe–Mg–Mn exchange between olivine and melt and an oxybarometer for basalts.

An experimentally validated numerical model for bubble growth in magma (2020)
Journal Article
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

Volcanic eruptions are driven by the growth of gas bubbles in magma. The timing and rate of bubble growth are important because they determine whether enough gas pressure can develop to fragment the melt. Bubbles grow in response to decompression and... Read More about An experimentally validated numerical model for bubble growth in magma.

An experimentally-validated numerical model of diffusion and speciation of water in rhyolitic silicate melt (2020)
Journal Article
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

The diffusion of water through silicate melts is a key process in volcanic systems. Diffusion controls the growth of the bubbles that drive volcanic eruptions and determines the evolution of the spatial distribution of dissolved water during and afte... Read More about An experimentally-validated numerical model of diffusion and speciation of water in rhyolitic silicate melt.