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Evidence for focused magmatic accretion at segment centers from lateral dike injections captured beneath the Red Sea rift in Afar

Keir, D., Hamling, I.J., Ayele, A., Calais, E., Ebinger, C., Wright, T.J., Jacques, E., Mohamed, K., Hammond, J.O.S., Belachew, M., Baker, E., Rowland, J.V., Lewi, E. and Bennati, L. (2009) Evidence for focused magmatic accretion at segment centers from lateral dike injections captured beneath the Red Sea rift in Afar. Geology, 37 (1). pp. 59-62. ISSN 0091-7613

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Abstract

Continental breakup occurs through repeated episodes of mechanical stretching and dike injection within discrete, narrow rift segments. However, the time and length scales of the dike intrusions, along with the source regions of melt within continental and oceanic rifts, are poorly constrained. We present measurements of spatial and temporal variability in deformation from the currently active 60-km-long Dabbahu segment of the Red Sea rift in Afar, using satellite radar, global positioning system, and seismicity data sets, that capture emplacement of two ~10-km-long, ~1–2-m-wide dike intrusions in June and July 2006. Our observations show that the majority of strain is accommodated by dikes that propagate laterally over ~4–5 h time scales along the rift axis and are sourced from a reservoir in the middle to lower crust, or upper mantle, beneath the center of the rift segment. New intrusions during the ongoing rifting episode in Afar show that the injection of lateral dikes fed from magma reservoirs beneath rift segment centers is a key component in creating and maintaining regular along-axis rift segmentation during the final stages of continental breakup. Our observations also provide evidence that the focused magmatic accretion at segment centers observed in slow-spreading mid-ocean ridges occurs prior to the onset of seafloor spreading.

Item Type: Article
Copyright, Publisher and Additional Information: © 2009 Geological Society of America. This is an author produced version of a paper published in Geology . Uploaded in accordance with the publisher's self archiving policy.
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds)
Depositing User: Sherpa Assistant
Date Deposited: 30 Jan 2009 14:39
Last Modified: 08 Feb 2013 17:05
Published Version: http://dx.doi.org/10.1130/G25147A.1
Status: Published
Publisher: Geological Society of America
Identification Number: 10.1130/G25147A.1
URI: http://eprints.whiterose.ac.uk/id/eprint/5434

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