Oceanic core complexes and crustal accretion at slow-spreading ridges

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doi: 10.1130/G23531A.1
Author(s): Ildefonse, Benoit; Blackman, D. K.; John, B. E.; Ohara, Y.; Miller, D. J.; MacLeod, C. J.; Abe, N.; Abratis, M.; Andal, E. S.; Andreani, M.; Awaji, S.; Beard, J. S.; Brunelli, D.; Charney, A. B.; Christie, D. M.; Delacour, A. G.; Delius, H.; Drouin, M.; Einaudi, F.; Escartin, J.; Frost, B. R.; Fryer, P. B.; Gee, J. S.; Godard, M.; Grimes, C. B.; Halfpenny, A.; Hansen, H. E.; Harris, A. C.; Hayman, N. W.; Hellebrand, E.; Hirose, T.; Hirth, J. G.; Ishimaru, S.; Johnson, K. T. M.; Karner, G. D.; Linek, M.; Maeda, J.; Mason, O. U.; McCaig, A. M.; Michibayashi, K.; Morris, A.; Nakagawa, T.; Nozaka, T.; Rosner, M.; Searle, R. C.; Suhr, G.; Tamura, A.; Tominaga, M.; von der Handt, A.; Yamasaki, T.; Zhao, X.
Integrated Ocean Drilling Program, Expedition 304, Shipboard Scientific Parties, College Station, TX
Author Affiliation(s): Primary:
Université de Montpellier II, Géosciences Montpellier, Montpellier, France
Other:
Scripps Institution of Oceanography, United States
University of Wyoming, United States
Ocean Research Laboratory, Japan
Integrated Ocean Drilling Program, United States
Cardiff University, United Kingdom
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 35(7), p.623-626. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2007165. 29 refs.; sects., sketch map
Summary: 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 peridotite: 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-slow-spreading ridges.
Year of Publication: 2007
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 05 Petrology, Igneous and Metamorphic; 18 Geophysics, Solid-Earth; Accretion; Atlantic Ocean; Atlantis Massif; Cores; Crust; Detachment faults; Emplacement; Expeditions 304/305; Faults; Gabbros; IODP Site U1309; Igneous rocks; Integrated Ocean Drilling Program; Intrusions; Lithosphere; Metaigneous rocks; Metamorphic rocks; Metasomatic rocks; Metasomatism; Mid-Atlantic Ridge; Mid-ocean ridges; ODP Site 735; Ocean Drilling Program; Ocean floors; Oceanic core complexes; Oceanic crust; Oceanic lithosphere; Peridotites; Plate tectonics; Plutonic rocks; Plutons; Sea-floor spreading; Serpentinite; Serpentinization; Spreading centers; Strain; Ultramafics
Coordinates: N301000 N301100 W0420600 W0420700
S324327 S324318 E0571618 E0571557
Record ID: 2007075936
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