Origin and significance of the Delaney Dome Formation, Connemara, Ireland
MetadataShow full item record
Dalradian meta-sediments of the Laurentian margin and mafic intrusions thereof in SW Connemara, Ireland, tectonically overlie meta-rhyolites of the Delaney Dome Formation. The two units are separated by the Mannin Thrust. A new U–Pb age of 474.6 ± 5.5 Ma shows that the Delaney Dome Formation is a temporal equivalent of arc volcanic rocks preserved in the adjacent South Mayo Trough: the Tourmakeady Volcanic Group, erupted during the collision of an oceanic island arc with the Laurentian margin in the Grampian Orogeny. New rare earth and high field strength element data show that the Delaney Dome Formation and Tourmakeady Volcanic Group are chemically similar and arc-like in character. This suggests that the Delaney Dome Formation is an along-strike equivalent of the Tourmakeady Group, strike-slip faulted south of the South Mayo Trough during or after the Grampian Orogeny. Further correlation of these units with northern Appalachian rhyolites is also possible. The Delaney Dome Formation is an extrusive temporal equivalent of intrusions that penetrate the Connemara Dalradian. Thus, movement along the Mannin Thrust brought mid-crustal plutons and Dalradian country rocks tectonically above the extrusive volcanic sequence. The Mannin Thrust is identified as a major imbricating structure within a continental arc, but not a terrane boundary.
Author Posting. © Geological Society of London, 2002. This article is posted here by permission of Geological Society of London for personal use, not for redistribution. The definitive version was published in Journal of the Geological Society 159 (2002): 95-103, doi: 10.1144/0016-764901034
Suggested CitationJournal of the Geological Society 159 (2002): 95-103
Showing items related by title, author, creator and subject.
Szpak, Michal T.; Monteys, Xavier; O'Reilly, S.; Simpson, A. J.; Garcia, Xavier; Evans, Rob L.; Allen, C. C. R.; McNally, D. J.; Courtier-Murias, D.; Kelleher, B. P. (American Geophysical Union, 2012-01-19)Marine pockmarks are a specific type of seabed geological setting resembling craters or pits and are considered seabed surface expressions of fluid flow in the subsurface. A large composite pockmark on the Malin Shelf, off ...
Constraints on a shallow offshore gas environment determined by a multidisciplinary geophysical approach : the Malin Sea, NW Ireland Garcia, Xavier; Monteys, Xavier; Evans, Rob L.; Szpak, Michal T. (John Wiley & Sons, 2014-04-02)During the Irish National Seabed Survey (INSS) in 2003, a gas related pockmark field was discovered and extensively mapped in the Malin Shelf region (NW Ireland). In summer 2006, additional complementary data involving ...
Laurentian crustal recycling in the Ordovician Grampian Orogeny : Nd isotopic evidence from western Ireland Draut, Amy E.; Clift, Peter D.; Chew, David M.; Cooper, Matthew J.; Taylor, Rex N.; Hannigan, Robyn E. (Cambridge University Press, 2004-04-21)Because magmatism associated with subduction is thought to be the principal source for continental crust generation, assessing the relative contribution of pre-existing (subducted and assimilated) continental material to ...