Petrology and rock magnetism of the gabbro of Troodos ophiolite

Y. Ebert*, R. Kessel, R. Shaar, A. Agnon, H. Ron

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


In order to determine the nature of remanence carriers of the layered gabbro of the Troodos ophiolite, Cyprus, we report optical and electron microscopic observations, together with rock magnetic and paleomagnetic experiments. Above all, the study aims to understand and clarify the time of magnetic acquisition relative to the brittle deformation of the oceanic crust manifested by the ridge-transform intersection (Solea graben and the Arakapas transform). Petrographic examination of pyroxene grains revealed isolated magnetite inclusions ranging in size from single-domain (SD) to multi-domain (MD) and in addition, MD pyrrhotite inclusions residing in veins and cracks. Thermal demagnetization and thermomagnetic procedures indicate two components, low and high temperature. We argue that the low temperature component, <350 °C, and the high component, <580 °C, are the contribution of the pyrrhotite and magnetite, respectively.The SD magnetite inclusions exsolved in pyroxene are the dominant carriers of magnetic remanence in Troodos Gabbro. The initial formation of these inclusions occurred via exsolution reaction at temperatures between 520 and 850 °C, above the Curie temperature of pure magnetite during the solidification of the magma. Therefore, acquisition of remanent magnetization of the Troodos gabbro took place during the earliest stages of crustal accretion, before any brittle deformation associated with the spreading ridge and the transform fault occurred.

Original languageAmerican English
Pages (from-to)413-420
Number of pages8
JournalPhysics of the Earth and Planetary Interiors
Issue number3-4
StatePublished - Dec 2010

Bibliographical note

Funding Information:
In conclusion, the rock magnetic properties of the Troodos gabbro imply that a dominant part of the remanent magnetization reside in SD and PSD grains. This conclusion is independently and mutually supported by the petrographic and rock magnetic characterization. In order to establish the timing of the ChRM acquisition, it is necessary to investigate the petrogenesis of the rock in general and the magnetite inclusions in particular.


  • Gabbro
  • Inclusions
  • Magnetite
  • Pyrrhotite
  • Rock magnetism
  • Troodos


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