A continuous 55-million-year record of transient mantle plume activity beneath Iceland

Research output: Contribution to journalArticlepeer-review

Authors

  • Ross Parnell-Turner
  • Nicky White
  • Tim Henstock
  • Bramley Murton
  • John Maclennan

Colleges, School and Institutes

External organisations

  • Univ Cambridge
  • National Oceanography Centre Southampton

Abstract

In the North Atlantic Ocean, a mid-ocean ridge bisects the Icelandic mantle plume, and provides a window into its temporal evolution. V-shaped ridges of thick oceanic crust observed south of Iceland are thought to record pulses of upwelling within the plume. Specifically, excess crust is thought to form during the quasi-periodic generation of hot solitary waves triggered by thermal instabilities in the mantle. Here we use seismic reflection data to show that V-shaped ridges have formed over the past 55 million years—providing the longest record of plume periodicity of its kind. We find evidence for minor, but systematic, asymmetric formation of crust, due to migration of the mid-ocean ridge with respect to the underlying plume. We also find changes in periodicity: from 55 to 35 million years ago, the V-shaped ridges form every 3 million years or so and reflect small fluctuations in plume temperature of about 5–10 °C. From 35 million years ago, the periodicity changes to about 8 million years and reflects changes in mantle temperature of 25–30 °C. We suggest that this change in periodicity is probably caused by perturbations in the thermal state at the plume source, either at the mantle-transition zone or core–mantle boundary.

Details

Original languageEnglish
Pages (from-to)914-919
Number of pages6
JournalNature Geoscience
Volume7
Issue number12
Early online date10 Nov 2014
Publication statusPublished - Dec 2014

Keywords

  • geodynamics, structural geology, tectonics, volcanology