Subvolcanic sheeted sills and nonsheeted dikes in ophiolites: Occurrence, origin, and tectonic significance for oceanic crust generation
Published:January 01, 2007
Clifford A. Hopson, 2007. "Subvolcanic sheeted sills and nonsheeted dikes in ophiolites: Occurrence, origin, and tectonic significance for oceanic crust generation", Convergent Margin Terranes and Associated Regions: A Tribute to W.G. Ernst, M. Cloos, W.D. Carlson, M.C. Gilbert, J.G. Liou, S.S. Sorensen
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Igneous intrusive sheets are conspicuous features of ophiolites formed at oceanic spreading centers. These include volcanic, subvolcanic, and plutonic dikes and sills and their subtypes. Attention is focused here on the subvolcanic sheets that separate the volcanic and plutonic members of ophiolites: the sheeted dikes, nonsheeted dikes, and the subvolcanic sheeted sills.
The sheeted dikes mark former crustal fissures that channeled magma to seafloor lava flows. They provide a record of continuous upper crustal extensional fracturing and coeval magmatism, characteristic of oceanic spreading centers. But some ophiolites have non-sheeted subvolcanic dikes instead. Those dikes are spaced apart, the intervening crustal...