Detrital U-Pb zircon dating of lower Ordovician syn-arc-continent collision conglomerates in the Irish Caledonides

P.D. Clift; A. Carter; A.E. Draut; H.V. Long; D.M. Chew; H.A. Schouten

doi:10.1016/j.tecto.2008.07.018

Detrital U-Pb zircon dating of lower Ordovician syn-arc-continent collision conglomerates in the Irish Caledonides

Tectonophysics

By: P.D. Clift, A. Carter, A.E. Draut, H.V. Long, D.M. Chew, and H.A. Schouten

https://doi.org/10.1016/j.tecto.2008.07.018

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Abstract

The Early Ordovician Grampian Orogeny in the British Isles represents a classic example of collision between an oceanic island arc and a passive continental margin, starting around 480 Ma. The South Mayo Trough in western Ireland preserves a complete and well-dated sedimentary record of arc collision. We sampled sandstones and conglomerates from the Rosroe, Maumtrasna and Derryveeny Formations in order to assess erosion rates and patterns during and after arc collision. U–Pb dating of zircons reveals a provenance dominated by erosion from the upper levels of the Dalradian Supergroup (Southern Highland and Argyll Groups), with up to 20% influx from the colliding arc into the Rosroe Formation, but only 6% in the Maumtrasna Formation (~ 465 Ma). The dominant source regions lay to the northeast (e.g. in the vicinity of the Ox Mountains, 50 km distant, along strike). The older portions of the North Mayo Dalradian and its depositional basement (the Annagh Gneiss Complex) do not appear to have been important sources, while the Connemara Dalradian only plays a part after 460 Ma, when it supplies the Derryveeny Formation. By this time all erosion from the arc had effectively ceased and exhumation rates had slowed greatly. The Irish Grampian Orogeny parallels the modern Taiwan collision in showing little role for the colliding arc in the production of sediment. Negligible volumes of arc crust are lost because of erosion during accretion to the continental margin.

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Additional publication details
Publication type	Article
Publication Subtype	Journal Article
Title	Detrital U-Pb zircon dating of lower Ordovician syn-arc-continent collision conglomerates in the Irish Caledonides
Series title	Tectonophysics
DOI	10.1016/j.tecto.2008.07.018
Volume	479
Issue	1-2
Year Published	2009
Language	English
Publisher	Elsevier
Description	10 p.
First page	165
Last page	174
Country	Ireland
Other Geospatial	British Isles
Google Analytic Metrics	Metrics page