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


Peirce, C., Gardiner, A. and 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. (doi:10.1111/j.1365-246X.2005.02738.x).

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Description/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.

Item Type: Article
ISSNs: 0956-540X (print)
Related URLs:
Keywords: crustal accretion, crustal structure, gravity anomalies, mid-ocean ridges, oceanic crust, residual mantle bouguer anomaly
Subjects: Q Science > QE Geology
G Geography. Anthropology. Recreation > GC Oceanography
Divisions: University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
ePrint ID: 17443
Date Deposited: 28 Sep 2005
Last Modified: 27 Mar 2014 18:07
URI: http://eprints.soton.ac.uk/id/eprint/17443

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