Skelton, Alsadair SL; Valley, John W (2000): Oxygen and carbon isotope ratios of silicates and carbonates from exhumed peridotites in the Iberian Abyssal Plain [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.711255, Supplement to: Skelton, ASL; Valley, JW (2000): The relative timing of serpentinisation and mantle exhumation at the ocean-continent transition, Iberia: constraints from oxygen isotopes. Earth and Planetary Science Letters, 178(3-4), 327-338, https://doi.org/10.1016/S0012-821X(00)00087-X
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Abstract:
Legs 173 and 149 of the Ocean Drilling Program profiled a zone of exhumed mantle peridotite at the ocean-continent transition (OCT) beneath the Iberia Abyssal Plain. The zone of exhumed peridotite appears to be tens of kilometers wide and is situated between blocks of continental crust and the first products of ocean accretion. Exhumed peridotite is 95-100% serpentinised to probable depths of 2-3 km. Down core oxygen isotope profiles of serpentinised peridotite at Sites 1068 and 1070 (Leg 173) show evidence for two fluid infiltration events. The earlier event involved pervasive infiltration of comparatively warm (>175°C) sea water and accompanied serpentinisation. The later event involved structurally focused infiltration of comparatively cool (650-150°C) sea water and accompanied active mantle exhumation. We therefore conclude that the uppermost mantle was serpentinised before it was exhumed at the Iberian OCT. Implicit to this conclusion is that a sizeable region of serpentinised mantle existed directly beneath thinned but intact continental crust. Serpentinite has comparatively low density, low frictional strength and low permeability. The presence of such a "soft" layer may have localised deformation and consequently promoted detachment-style exhumation of the uppermost mantle. The low permeability of a serpentinite 'cap' layer might help to explain the lack of observed melt at the Iberian OCT.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 40.739442 * Median Longitude: -12.167917 * South-bound Latitude: 40.682583 * West-bound Longitude: -12.723833 * North-bound Latitude: 40.796300 * East-bound Longitude: -11.612000
Date/Time Start: 1997-05-10T00:00:00 * Date/Time End: 1997-06-07T00:00:00
Event(s):
173-1068 * Latitude: 40.682583 * Longitude: -11.612000 * Date/Time Start: 1997-05-10T00:00:00 * Date/Time End: 1997-05-22T00:00:00 * Elevation: -5043.9 m * Penetration: 955.8 m * Recovery: 180.6 m * Location: South Atlantic Ocean * Campaign: Leg173 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 29 cores; 244.5 m cored; 711.3 m drilled; 73.9% recovery
173-1070 * Latitude: 40.796300 * Longitude: -12.723833 * Date/Time Start: 1997-05-31T00:00:00 * Date/Time End: 1997-06-07T00:00:00 * Elevation: -5321.8 m * Penetration: 718.8 m * Recovery: 51.8 m * Location: South Atlantic Ocean * Campaign: Leg173 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 14 cores; 119.8 m cored; 599 m drilled; 43.2% recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
4 datasets
Download Data
Datasets listed in this publication series
- Skelton, ASL; Valley, JW (2000): (Table 2) Carbonate oxygen and carbon isotope ratios of ODP Site 173-1068. https://doi.org/10.1594/PANGAEA.711253
- Skelton, ASL; Valley, JW (2000): (Table 1) Silicate oxygen isotope ratios of amphibolite and serpentine from ODP Site 173-1068. https://doi.org/10.1594/PANGAEA.711251
- Skelton, ASL; Valley, JW (2000): (Table 2) Carbonate oxygen and carbon isotope ratios of ODP Site 173-1070. https://doi.org/10.1594/PANGAEA.711254
- Skelton, ASL; Valley, JW (2000): (Table 1) Silicate oxygen isotope ratios of amphibolite and serpentine from ODP Site 173-1070. https://doi.org/10.1594/PANGAEA.711252