CO2 degassing and melting of metasomatized mantle lithosphere during rifting – Numerical study

Weronika Gorczyk, Christopher M. Gonzalez

    Research output: Contribution to journalArticle

    Abstract

    Reactivation of metasomatized mantle lithosphere may occur during continental extension, which is an important component of plate tectonics. The lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in CO2. Therefore, partial melting of these metasomatized domains may play a crucial role in the global carbon cycle. However, little is known about this process and up until now few numerical constraints are available. Here we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric rifting, CO2 degassing and melting. We test 4 lithospheric thicknesses: 90, 110, 130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.% in the bulk composition. The carbonate enriched layer is stable below ∼3 GPa (>110 km) for a temperature of 1300 °C; therefore, we only observe degassing patterns for lithospheric models that are 130 km and 200 km thick. The metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting, whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during extension. The numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young (shallow) and of the North Atlantic Rift for old (thick) lithosphere.

    Original languageEnglish
    JournalGeoscience Frontiers
    DOIs
    Publication statusE-pub ahead of print - 27 Dec 2018

    Fingerprint

    degassing
    rifting
    lithosphere
    melting
    mantle
    carbonatite
    plate tectonics
    carbon cycle
    reactivation
    partial melting
    melt
    carbonate
    temperature

    Cite this

    @article{52c0ac1fbdcc46fb8b19d054dba42c7f,
    title = "CO2 degassing and melting of metasomatized mantle lithosphere during rifting – Numerical study",
    abstract = "Reactivation of metasomatized mantle lithosphere may occur during continental extension, which is an important component of plate tectonics. The lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in CO2. Therefore, partial melting of these metasomatized domains may play a crucial role in the global carbon cycle. However, little is known about this process and up until now few numerical constraints are available. Here we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric rifting, CO2 degassing and melting. We test 4 lithospheric thicknesses: 90, 110, 130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.{\%} in the bulk composition. The carbonate enriched layer is stable below ∼3 GPa (>110 km) for a temperature of 1300 °C; therefore, we only observe degassing patterns for lithospheric models that are 130 km and 200 km thick. The metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting, whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during extension. The numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young (shallow) and of the North Atlantic Rift for old (thick) lithosphere.",
    keywords = "Carbonate melting, Mantle CO degassing, Rifting",
    author = "Weronika Gorczyk and Gonzalez, {Christopher M.}",
    year = "2018",
    month = "12",
    day = "27",
    doi = "10.1016/j.gsf.2018.11.003",
    language = "English",
    journal = "Geoscience Frontiers",
    issn = "1674-9871",
    publisher = "CHINA UNIV GEOSCIENCES, BEIJING",

    }

    CO2 degassing and melting of metasomatized mantle lithosphere during rifting – Numerical study. / Gorczyk, Weronika; Gonzalez, Christopher M.

    In: Geoscience Frontiers, 27.12.2018.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - CO2 degassing and melting of metasomatized mantle lithosphere during rifting – Numerical study

    AU - Gorczyk, Weronika

    AU - Gonzalez, Christopher M.

    PY - 2018/12/27

    Y1 - 2018/12/27

    N2 - Reactivation of metasomatized mantle lithosphere may occur during continental extension, which is an important component of plate tectonics. The lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in CO2. Therefore, partial melting of these metasomatized domains may play a crucial role in the global carbon cycle. However, little is known about this process and up until now few numerical constraints are available. Here we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric rifting, CO2 degassing and melting. We test 4 lithospheric thicknesses: 90, 110, 130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.% in the bulk composition. The carbonate enriched layer is stable below ∼3 GPa (>110 km) for a temperature of 1300 °C; therefore, we only observe degassing patterns for lithospheric models that are 130 km and 200 km thick. The metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting, whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during extension. The numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young (shallow) and of the North Atlantic Rift for old (thick) lithosphere.

    AB - Reactivation of metasomatized mantle lithosphere may occur during continental extension, which is an important component of plate tectonics. The lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in CO2. Therefore, partial melting of these metasomatized domains may play a crucial role in the global carbon cycle. However, little is known about this process and up until now few numerical constraints are available. Here we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric rifting, CO2 degassing and melting. We test 4 lithospheric thicknesses: 90, 110, 130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.% in the bulk composition. The carbonate enriched layer is stable below ∼3 GPa (>110 km) for a temperature of 1300 °C; therefore, we only observe degassing patterns for lithospheric models that are 130 km and 200 km thick. The metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting, whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during extension. The numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young (shallow) and of the North Atlantic Rift for old (thick) lithosphere.

    KW - Carbonate melting

    KW - Mantle CO degassing

    KW - Rifting

    UR - http://www.scopus.com/inward/record.url?scp=85059052114&partnerID=8YFLogxK

    U2 - 10.1016/j.gsf.2018.11.003

    DO - 10.1016/j.gsf.2018.11.003

    M3 - Article

    JO - Geoscience Frontiers

    JF - Geoscience Frontiers

    SN - 1674-9871

    ER -