Skip to content

Research at St Andrews

Insights into the compositional evolution of crustal magmatic systems from coupled petrological-geodynamical models

Research output: Contribution to journalArticle

Open Access Status

  • Embargoed (until 19/02/21)

Author(s)

Lisa Rummel, Boris Kaus, Tobias Baumannn, Richard William White, Nicolas Riel

School/Research organisations

Abstract

The evolution of crustal magmatic systems is incompletely understood, as most studies are limited either by their temporal or spatial resolution. Exposed plutonic rocks represent the final stage of a long-term evolution punctuated by several magmatic events with different chemistry and generated under different mechanical conditions. Although the final state can be easily described, the nature of each magmatic pulse is more difficult to retrieve. This study presents a new method to investigate the compositional evolution of plutonic systems while considering thermal and mechanical processes. A thermomechanical code (MVEP2) extended by a semi-analytical dike/sill formation algorithm, is combined with a thermodynamic modelling approach (Perple_X) to investigate the feedback between petrology and mechanics. Melt is extracted to form dikes while depleting the source region. The evolving rock compositions are tracked on markers using a different phase diagram for each discrete bulk-rock composition. The rock compositional evolution is thus tracked with a high precision by means of a database with more than 58,000 phase diagrams. This database describes how density, melt fraction, chemical composition of melt and solid fractions and mineralogical assemblages change over crustal to uppermost mantle P-T conditions for a large range of rock compositions. Each bulk rock composition is composed of the 10 major oxides (SiO2-TiO2-Al2O3-Cr2O3-MgO-FeO-CaO-Na2O-K2O-H2O) including an oxygen buffer. The combined modelling approach is applied to study the chemical evolution of the crust during arc magmatism and related melt extraction and magma mixing processes. Basaltic sills are periodically injected into the crust to model heat/magma influx from the mantle. We find that accumulated sills turn into long-lived mush chambers when using a lower rock cohesion or assuming a higher intrusion depth. Associated partial melting of crustal host rocks occurs around densely distributed dikes and sills. High silica rocks (e.g. granites) are generated by partial melting of the host rocks, melt segregation within dikes, and from fractional crystallization of basalts. Although the volume of these rocks is relatively small in our models compared to rocks with a mafic to intermediate composition, they provide important information about the processes of magma differentiation within arc continental crust.
Close

Details

Original languageEnglish
Article numberegaa029
JournalJournal of Petrology
VolumeIn press
Early online date19 Feb 2020
DOIs
Publication statusE-pub ahead of print - 19 Feb 2020

    Research areas

  • Coupled petrological-geodynamical models, Depletion of rocks through diking, Highly evolved rocks, Large phase diagram database, Long-lived mush chambers

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. The fate of accessory minerals and key trace elements during anatexis and magma extractio

    Schwindinger, M., Weinberg, R. & White, R. W., 19 Feb 2020, In : Journal of Petrology. In press, egaa031.

    Research output: Contribution to journalArticle

  2. The truth and beauty of chemical potentials

    Powell, R., Evans, K. A., Green, E. C. R. & White, R. W., 2 May 2019, In : Journal of Metamorphic Geology. Early View

    Research output: Contribution to journalArticle

  3. Generation of Earth's early continents from a relatively cool Archean mantle

    Piccolo, A., Palin, R. M., Kaus, B. J. P. & White, R. W., Apr 2019, In : Geochemistry, Geophysics, Geosystems. 20, 4, p. 1679-1697 19 p.

    Research output: Contribution to journalArticle

  4. Can we extract ultrahigh-temperature conditions from Fe-rich metapelites? An example from the Khondalite Belt, North China Craton

    Li, X., White, R. W. & Wei, C., Mar 2019, In : Lithos. 328-329, p. 228-243

    Research output: Contribution to journalArticle

Related by journal

  1. Journal of Petrology (Journal)

    Anouk Margaretha Borst (Reviewer)
    12 Jan 2020

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

  2. Journal of Petrology (Journal)

    Anouk Margaretha Borst (Reviewer)
    7 May 2019

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

Related by journal

  1. The fate of accessory minerals and key trace elements during anatexis and magma extractio

    Schwindinger, M., Weinberg, R. & White, R. W., 19 Feb 2020, In : Journal of Petrology. In press, egaa031.

    Research output: Contribution to journalArticle

  2. Modelling the hafnium-neodymium evolution of early Earth: a study from West Greenland

    Gardiner, N. J., Johnson, T. E., Kirkland, C. L. & Szilas, K., Jan 2019, In : Journal of Petrology. 60, 1, p. 177-197 21 p.

    Research output: Contribution to journalArticle

  3. Bulk and mush melt evolution in agpaitic intrusions: insights from compositional zoning in eudialyte, Ilimaussaq complex, South Greenland

    Borst, A. M., Friis, H., Nielsen, T. F. D. & Waight, T. E., 14 Apr 2018, In : Journal of Petrology. 59, 4, p. 589-611 23 p.

    Research output: Contribution to journalArticle

  4. Using zircon isotope compositions to constrain crustal structure and Pluton evolution: the Iapetus Suture Zone granites in Northern Britain

    Miles, A., Graham, C., Hawkesworth, C., Gillespie, M., Dhuime, B. & Hinton, R., Jan 2014, In : Journal of Petrology. 55, 1, p. 181-207 27 p.

    Research output: Contribution to journalArticle

ID: 267128603

Top