Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/118885
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- Title
- Lithospheric structure of the Gorringe Bank : insights into its origin and tectonic evolution
- Related
- Tectonics, Vol. 29, No. 5 (2010), p.TC5019-1-TC5019-16
- DOI
- 10.1029/2009TC002458
- Publisher
- American Geophysical Union
- Date
- 2010
- FoR/RFCD Code(s)
-
040400 Geophysics
040300 Geology
- Author/Creator
- Jiménez-Munt, I
- Author/Creator
- Fernàndez, M
- Author/Creator
- Vergés, J
- Author/Creator
- Afonso, J. C
- Author/Creator
- Garcia-Castellanos, D
- Author/Creator
- Fullea, J
- Description
- The Gorringe Bank is a 5000 m high seamount near the Atlantic coast of Iberia characterized by a 9 m high geoid anomaly and a ∼120 mGal Bouguer anomaly relative to the surrounding abyssal plains. It has been linked to a NW directed thrust carrying exhumed upper mantle rocks and transitional crust on top of flexed-down Eurasian oceanic crust along the Tagus Abyssal Plain. However, estimations of crustal shortening have yielded dissimilar results, and the deep structure of the ridge remains highly unknown. We present a restored cross section and a new model of the lithospheric structure based on gravity, geoid, elevation, and the presence of serpentinized peridotites. At least 20 km of shortening took place along a flat-ramp-flat thrust fault, and the density structure of the lithosphere is consistent with mantle serpentinization varying from 70% at the surface to 20% at 14 km depth and 0% at 40 km. The topographic relief and gravity anomalies are explained by assuming a flexural isostatic model with an elastic thickness Te of ∼30 km. The evolution of the Gorringe Bank since the Late Jurassic is interpreted in relation to Eurasia-Africa-North America plate motion in four stages: (1) transtension between Newfoundland-Iberia and Africa, which generated small oceanic basins and mantle exhumation; (2) opening of the North Atlantic and seafloor spreading at the NW side of the exhumed Gorringe, which produced gabbro intrusions and serpentinization; (3) a quiescent tectonic period dominated by subsidence and sediment accumulation; and (4) a transpressional plate boundary between Eurasia and Africa with NW directed subcrustal thrusting and generation of the present Gorringe relief.
- Description
- 16 page(s)
- Subject Keyword
- 040400 Geophysics
- Subject Keyword
- 040300 Geology
- Subject Keyword
- potential fields
- Subject Keyword
- serpentinized
- Subject Keyword
- peridotites
- Subject Keyword
- gabbros
- Resource Type
- journal article
- Organisation
- Macquarie University. National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC)
- Identifier
- http://hdl.handle.net/1959.14/118885
- Identifier
- ISSN:0278-7407
- Identifier
- mq-rm-2010004124
- Language
- eng
- Rights
- Copyright 2010 by the American Geophysical Union. Originally published as Jiménez-Munt, I., M. Fernàndez, J. Vergés, J. C. Afonso, D. Garcia-Castellanos, and J. Fullea (2010), Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution, Tectonics, 29, TC5019. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.
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