Initiation of Iapetus subduction under Irish avalonia
By: McConnell, Brian
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Contributor(s): Morris, John.
Material type: 
ArticleDescription: 213-218pp ; Illustration.Subject(s): Continental margin - Europe - Mount seskin anticline | Plutenic rocks | Merioneth shire wales | Ordovician | Aghfurrell formation
In:
Geological magazine : Vol. 134 Iss. 1-6 Year. 1997Summary: The Dowery Hill Member of metamorphosed basalt, dolerite and siltstone is here recognized as the oldest exposed volcanic unit of the Lower Ordovician Ribband Group, with a minimum age of early Arenig. Peperites and resedimented hydroclastic breccia demonstrate a volcanic origin for the basalts. The igneous rocks are tholeiitic, with a trace element geochemistry indicative of a subduction-modified fertile mantle source, which we interpret as recording an early stage of volcanic arc evolution. The member is therefore the oldest known component of the volcanic arc generated by subduction of Iapetus oceanic lithosphere under southeastern Ireland. Subduction started earlier than predicted by current plate tectonic models, and these should be re-evaluated.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Article
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Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002523_56 | ||
Serials/Scientific Journal
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Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002523 |
The Dowery Hill Member of metamorphosed basalt, dolerite and siltstone is here recognized as the oldest exposed volcanic unit of the Lower Ordovician Ribband Group, with a minimum age of early Arenig. Peperites and resedimented hydroclastic breccia demonstrate a volcanic origin for the basalts. The igneous rocks are tholeiitic, with a trace element geochemistry indicative of a subduction-modified fertile mantle source, which we interpret as recording an early stage of volcanic arc evolution. The member is therefore the oldest known component of the volcanic arc generated by subduction of Iapetus oceanic lithosphere under southeastern Ireland. Subduction started earlier than predicted by current plate tectonic models, and these should be re-evaluated.
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