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Temporal and spatial cyclicity of accretion at slow-spreading ridges - evidence from the Reykjanes Ridge

Peirce, C.; Gardiner, A.; Sinha, M.C.

Temporal and spatial cyclicity of accretion at slow-spreading ridges - evidence from the Reykjanes Ridge Thumbnail


Authors

A. Gardiner

M.C. Sinha



Abstract

A unifying model of oceanic crustal development at slow spreading rates is presented in which accretion follows a cyclic pattern of magmatic construction and tectonic destruction, controlled by along-axis variation in melt supply and coupled to along-axis variation in spreading rate and across-axis asymmetry in spreading. This study focuses on the Reykjanes Ridge, Mid-Atlantic Ridge south of Iceland, which is divided along its entire length into numerous axial volcanic ridges (AVR). Five adjacent AVRs have been analysed, located between 57°30'N and 58°30'N and south of any strong Iceland hotspot influence. The seabed morphology of each AVR is investigated using sidescan sonar data to determine relative age and eruptive history. Along-axis gravity profiles for each AVR are modelled relative to a seismically derived crustal reference model, to reveal the underlying crustal thickness and density structure. Correlating these models with seabed features, crustal structure, ridge segment morphology and relative ages, a model of cyclic ridge segmentation is developed in which accretion results in adjacent AVRs with a range of crustal features which, when viewed collectively, reveal that second-order segments on the Reykjanes Ridge have an along-axis length of 70 km and comprise several adjacent AVRs which, in turn, reflect the pattern of third-order segmentation. Tectono-magmatic accretion is shown to operate on the scale of individual AVRs, as well as on the scale of the second-order segment as a whole.

Citation

Peirce, C., Gardiner, A., & Sinha, M. (2005). Temporal and spatial cyclicity of accretion at slow-spreading ridges - evidence from the Reykjanes Ridge. Geophysical Journal International, 163(1), 56-78. https://doi.org/10.1111/j.1365-246x.2005.02738.x

Journal Article Type Article
Publication Date 2005-10
Deposit Date Jul 9, 2007
Publicly Available Date Jul 30, 2010
Journal Geophysical Journal International
Print ISSN 0956-540X
Electronic ISSN 1365-246X
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 163
Issue 1
Pages 56-78
DOI https://doi.org/10.1111/j.1365-246x.2005.02738.x
Keywords Crustal accretion, Crustal structure, Gravity anomalies, Mid-ocean ridges, Oceanic crust, Residual mantle Bouguer anomaly.

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The definitive version is available at www.blackwell-synergy.com.





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