Oceanic core complexes and crustal accretion at slow-speading ridges

Benoit Ildefonse, D. K. Blackman, B. E. John, Y. Ohara, D. J. Miller, C. J. MacLeod, N. Abe, M. Abratis, E. S. Andal, M. Andréani, S. Awaji, J. S. Beard, D. Brunelli, A. B. Charney, D. M. Christie, A. G. Delacour, H. Delius, M. Drouin, F. Einaudi, J. EscartinB. R. Frost, P. B. Fryer, J. S. Gee, M. Godard, C. B. Grimes, A. Halfpenny, H. E. Hansen, A. C. Harris, N. W. Hayman, E. Hellebrand, T. Hirose, J. G. Hirth, S. Ishimaru, K. T M Johnson, G. D. Karner, M. Linek, J. Maeda, O. U. Mason, A. M. McCaig, K. Michibayashi, A. Morris, T. Nakagawa, Toshio Nozaka, M. Rosner, R. C. Searle, G. Suhr, A. Tamura, M. Tominaga, A. von der Handt, T. Yamasaki, X. Zhao

Research output: Contribution to journalArticle

224 Citations (Scopus)

Abstract

Oceanic core complexes expose gabbroic rocks on the seafloor via detachment faulting, often associated with serpentinized peridotite. The thickness of these serpentinite units is unknown. Assuming that the steep slopes that typically surround these core complexes provide a cross section through the structure, it has been inferred that serpentinites compose much of the section to depths of at least several hundred meters. However, deep drilling at oceanic core complexes has recovered gabbroic sequences with virtually no serpentinized peridotite. We propose a revised model for oceanic core complex development based on consideration of the rheological differences between gabbro and serpentinized peridobte: emplacement of a large intrusive gabbro body into a predominantly peridotite host is followed by localization of strain around the margins of the pluton, eventually resulting in an uplifted gabbroic core surrounded by deformed serpentinite. Oceanic core complexes may therefore reflect processes associated with relatively enhanced periods of mafic intrusion within overall magma-poor regions of slow- and ultra-dow-spreading ridges.

Original languageEnglish
Pages (from-to)623-626
Number of pages4
JournalGeology
Volume35
Issue number7
DOIs
Publication statusPublished - Jul 2007
Externally publishedYes

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Keywords

  • Gabbro
  • Integrated Ocean Dilling Program
  • Mid-Atlantic Ridge
  • Mid-ocean ridges
  • Ocean Drilling Program
  • Oceanic core complex
  • Oceanic lithosphere
  • Serpentinite

ASJC Scopus subject areas

  • Geology

Cite this

Ildefonse, B., Blackman, D. K., John, B. E., Ohara, Y., Miller, D. J., MacLeod, C. J., Abe, N., Abratis, M., Andal, E. S., Andréani, M., Awaji, S., Beard, J. S., Brunelli, D., Charney, A. B., Christie, D. M., Delacour, A. G., Delius, H., Drouin, M., Einaudi, F., ... Zhao, X. (2007). Oceanic core complexes and crustal accretion at slow-speading ridges. Geology, 35(7), 623-626. https://doi.org/10.1130/G23531A.1