A Canary Island dyke swarm; implications for the formation of oceanic islands by extensional fissural volcanism

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Authors:Stillman, C. J.
Author Affiliations:Primary:
Trinity Coll., Dep. Geol., Dublin, Ireland
Other:
Geol. Surv. Can., Canada
Volume Title:Mafic dyke swarms; a collection of papers based on the proceedings of an international conference
Volume Authors:Halls, Henry C., editor; Fahrig, Walter F.
Source:Special Paper - Geological Association of Canada, Vol.34, p.243-255; Mafic dyke swarms; international conference, Mississauga, ON, Canada, June 4-7, 1985, edited by Henry C. Halls and Walter F. Fahrig. Publisher: Geological Association of Canada, Toronto, ON, Canada. ISSN: 0072-1042. ISBN: 0-919216-33-1
Publication Date:1987
Note:In English with French summary. 48 refs.; illus. incl. 2 tables, geol. sketch maps
Summary:On the island of Fuerteventura, Canary Islands, an extensive basal complex is dominated by a dyke swarm in the axial zone of which dilation exceeds 80%. The swarm has many of the features of a sheeted dyke swarm and is associated with small high-level plutons that appear to be comagmatic with many of the dykes. The dykes were emplaced in a parallel series of dilational fissures which together make up a fissure swarm similar in form and dimension to those of the mid-ocean ridge as seen in the Reykjanes peninsula. However, in Fuerteventura the fissure swarm forms part of a volcano edifice. The dykes were injected into a NNE-trending zone that initially formed within ocean crust close to the region of transition to African continental crust. Magma was emplaced in a series of dilational episodes over >36 m.y., from Palaeocene to early Miocene times. A mechanism is suggested for the evolution of the middle Atlantic volcanic islands above a long-lasting linear melting anomaly in the mantle, with individual eruptive centres located by fissures produced by extensional stresses in the oceanic lithosphere. (Author's abstract) [A.W.H.]
Subjects:Cenozoic; Complexes; Continental crust; Crust; Dike swarms; Dikes; Dilation; Emplacement; Extension tectonics; Fissures; Genesis; Geochemistry; Intrusions; Island arcs; Lithosphere; Mafic composition; Magmas; Mantle; Oceanic crust; Ophiolite; Petrology; Plate tectonics; Plutons; Stress; Tectonics; Tectonophysics; Tertiary; Volcanism; Atlantic Ocean Islands; Canary Islands; Europe; Iceland; Reykjanes Peninsula; Western Europe; Fuerteventura Island
Coordinates:N274500 N291500 W0130000 W0180000
Abstract Numbers:88M/6290
Record ID:1989018604
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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