Potential role of strain hardening in the cessation of rifting at constant tectonic force

T. Yamasaki, R.A. Stephenson

    Research output: Contribution to JournalArticleAcademicpeer-review

    Abstract

    In this study the cessation of rifting at constant tectonic force is discussed from the viewpoint of lithospheric rheology using a simple one-dimensional numerical model. The behaviour of the conventionally adopted constant force model re-examined in this study contradicts some general features in the development of sedimentary basins. Strain hardening is implemented to explain the contradictions, in which the viscosity of the mantle is a function of not only the strain rate and temperature but also the total strain. The roles of various strain hardening parameters in rifting dynamics are examined, including the strain required for the onset of hardening, the strain interval required for the completion of hardening and the factor controlling the increase in mantle viscosity. It is shown that a model with strain hardening can explain many characteristic features of sedimentary basin formation better than the conventional constant force model. There are a variety of ways in which rifting can be terminated by the strain hardening model, depending on the initial lithospheric structure, magnitude of tectonic force and the hardening process. One possible strain hardening mechanism involves the switch from wet to dry rheology associated with decompressional melting, though the implemented strain hardening formula could be generally applicable to any hardening phenomenon and could therefore be physically interpreted as such. The results of this study also provide important insights into sedimentary basin subsidence in relation to rifting dynamics. The end of an initial rapid ("syn-rift" like) subsidence phase is not necessarily equivalent to the end of actual rifting as in the constant force model. The transition from initial rapid subsidence to long-term, more subdued ("post-rift" like), subsidence is actually marked by the onset of deceleration of rifting. Since significant extension still continues for some time thereafter, the subsequent long-term subsidence includes some mechanical effect of crustal thinning. © 2008 Elsevier Ltd. All rights reserved.
    Original languageEnglish
    Pages (from-to)47-62
    JournalJournal of Geodynamics
    Volume47
    DOIs
    Publication statusPublished - 2009

    Fingerprint

    strain hardening
    hardening
    subsidence
    rifting
    tectonics
    rheology
    sedimentary basin
    Earth mantle
    viscosity
    deceleration
    strain rate
    mantle
    switches
    lithospheric structure
    crustal thinning
    melting
    intervals
    basin evolution

    Cite this

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    title = "Potential role of strain hardening in the cessation of rifting at constant tectonic force",
    abstract = "In this study the cessation of rifting at constant tectonic force is discussed from the viewpoint of lithospheric rheology using a simple one-dimensional numerical model. The behaviour of the conventionally adopted constant force model re-examined in this study contradicts some general features in the development of sedimentary basins. Strain hardening is implemented to explain the contradictions, in which the viscosity of the mantle is a function of not only the strain rate and temperature but also the total strain. The roles of various strain hardening parameters in rifting dynamics are examined, including the strain required for the onset of hardening, the strain interval required for the completion of hardening and the factor controlling the increase in mantle viscosity. It is shown that a model with strain hardening can explain many characteristic features of sedimentary basin formation better than the conventional constant force model. There are a variety of ways in which rifting can be terminated by the strain hardening model, depending on the initial lithospheric structure, magnitude of tectonic force and the hardening process. One possible strain hardening mechanism involves the switch from wet to dry rheology associated with decompressional melting, though the implemented strain hardening formula could be generally applicable to any hardening phenomenon and could therefore be physically interpreted as such. The results of this study also provide important insights into sedimentary basin subsidence in relation to rifting dynamics. The end of an initial rapid ({"}syn-rift{"} like) subsidence phase is not necessarily equivalent to the end of actual rifting as in the constant force model. The transition from initial rapid subsidence to long-term, more subdued ({"}post-rift{"} like), subsidence is actually marked by the onset of deceleration of rifting. Since significant extension still continues for some time thereafter, the subsequent long-term subsidence includes some mechanical effect of crustal thinning. {\circledC} 2008 Elsevier Ltd. All rights reserved.",
    author = "T. Yamasaki and R.A. Stephenson",
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    Potential role of strain hardening in the cessation of rifting at constant tectonic force. / Yamasaki, T.; Stephenson, R.A.

    In: Journal of Geodynamics, Vol. 47, 2009, p. 47-62.

    Research output: Contribution to JournalArticleAcademicpeer-review

    TY - JOUR

    T1 - Potential role of strain hardening in the cessation of rifting at constant tectonic force

    AU - Yamasaki, T.

    AU - Stephenson, R.A.

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    AB - In this study the cessation of rifting at constant tectonic force is discussed from the viewpoint of lithospheric rheology using a simple one-dimensional numerical model. The behaviour of the conventionally adopted constant force model re-examined in this study contradicts some general features in the development of sedimentary basins. Strain hardening is implemented to explain the contradictions, in which the viscosity of the mantle is a function of not only the strain rate and temperature but also the total strain. The roles of various strain hardening parameters in rifting dynamics are examined, including the strain required for the onset of hardening, the strain interval required for the completion of hardening and the factor controlling the increase in mantle viscosity. It is shown that a model with strain hardening can explain many characteristic features of sedimentary basin formation better than the conventional constant force model. There are a variety of ways in which rifting can be terminated by the strain hardening model, depending on the initial lithospheric structure, magnitude of tectonic force and the hardening process. One possible strain hardening mechanism involves the switch from wet to dry rheology associated with decompressional melting, though the implemented strain hardening formula could be generally applicable to any hardening phenomenon and could therefore be physically interpreted as such. The results of this study also provide important insights into sedimentary basin subsidence in relation to rifting dynamics. The end of an initial rapid ("syn-rift" like) subsidence phase is not necessarily equivalent to the end of actual rifting as in the constant force model. The transition from initial rapid subsidence to long-term, more subdued ("post-rift" like), subsidence is actually marked by the onset of deceleration of rifting. Since significant extension still continues for some time thereafter, the subsequent long-term subsidence includes some mechanical effect of crustal thinning. © 2008 Elsevier Ltd. All rights reserved.

    U2 - 10.1016/j.jog.2008.07.001

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    M3 - Article

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    JO - Journal of Geodynamics

    JF - Journal of Geodynamics

    SN - 0264-3707

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