Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation

Deformation of continental lithosphere leading to breakup and the initiation of seafloor spreading can be described in terms of an upwelling divergent flow field within the continental lithosphere and asthenosphere. A new model (SfMargin) of rifted continental margin formation using this upwellin...

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Main Authors: Healy, David, Kusznir, N.
Format: Book Chapter
Published: Geological Society of London 2007
Online Access:http://hdl.handle.net/20.500.11937/35280
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author Healy, David
Kusznir, N.
author_facet Healy, David
Kusznir, N.
author_sort Healy, David
building Curtin Institutional Repository
collection Online Access
description Deformation of continental lithosphere leading to breakup and the initiation of seafloor spreading can be described in terms of an upwelling divergent flow field within the continental lithosphere and asthenosphere. A new model (SfMargin) of rifted continental margin formation using this upwelling divergent flow field has been developed that successfully predicts lithosphere depth-dependent stretching and mantle exhumation at rifted margins. The kinematics of this flow field has important consequences for the bathymetric (subsidence) and thermal history of continental margin lithosphere. We apply the new model to a profile through the Goban Spur on the eastern Atlantic continental margin. Forward modelling yields parameter values describing the kinematics of the flow field leading to continental breakup and sea-floor spreading initiation that are consistent with the known amagmatic history of this margin. We employ a grid search method to systematically explore model parameter space and provide an assessment of the sensitivity of the model to the kinematic flow field parameter values. The preferred forward model parameters coincide with low values of misfit with respect to observed present-day bathymetry and free air gravity anomalies. Our results reveal the early kinematic history of the Goban Spur margin as characterized by a ratio of upwelling rate to half-spreading rate of unity, consistent with that expected for the initiation of sea-floor spreading at a non-volcanic rifted margin and only a modest amount of prebreakup lithospheric stretching (b ¼ 1.5). These results conform with recent observations of depth-dependent stretching and serpentinized mantle exhumation at this amagmatic rifted continental margin.
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spelling curtin-20.500.11937-352802017-02-28T01:41:36Z Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation Healy, David Kusznir, N. Deformation of continental lithosphere leading to breakup and the initiation of seafloor spreading can be described in terms of an upwelling divergent flow field within the continental lithosphere and asthenosphere. A new model (SfMargin) of rifted continental margin formation using this upwelling divergent flow field has been developed that successfully predicts lithosphere depth-dependent stretching and mantle exhumation at rifted margins. The kinematics of this flow field has important consequences for the bathymetric (subsidence) and thermal history of continental margin lithosphere. We apply the new model to a profile through the Goban Spur on the eastern Atlantic continental margin. Forward modelling yields parameter values describing the kinematics of the flow field leading to continental breakup and sea-floor spreading initiation that are consistent with the known amagmatic history of this margin. We employ a grid search method to systematically explore model parameter space and provide an assessment of the sensitivity of the model to the kinematic flow field parameter values. The preferred forward model parameters coincide with low values of misfit with respect to observed present-day bathymetry and free air gravity anomalies. Our results reveal the early kinematic history of the Goban Spur margin as characterized by a ratio of upwelling rate to half-spreading rate of unity, consistent with that expected for the initiation of sea-floor spreading at a non-volcanic rifted margin and only a modest amount of prebreakup lithospheric stretching (b ¼ 1.5). These results conform with recent observations of depth-dependent stretching and serpentinized mantle exhumation at this amagmatic rifted continental margin. 2007 Book Chapter http://hdl.handle.net/20.500.11937/35280 Geological Society of London restricted
spellingShingle Healy, David
Kusznir, N.
Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
title Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
title_full Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
title_fullStr Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
title_full_unstemmed Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
title_short Early kinematic history of the Goban Spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
title_sort early kinematic history of the goban spur rifted margin derived from a new model of continental breakup and sea floor spreading initiation
url http://hdl.handle.net/20.500.11937/35280