Laurentian origin of the Ordovician Grangegeeth volcanic arc terrane, Ireland

• Main Authors: Brian McConnell, Quentin G. Crowley, Nancy Riggs
• Format: Dataset
• Language: unknown
• Published: 2016
• Subjects: Geology; arc terrane; Laurentian origin; Ireland; age spectra; Ordovician Grangegeeth; 700 Ma; zircon population; lithic pumice tuff; 199 zircons; Laurentian crust; metasedimentary successions; Inherited zircons; plasma mass spectrometry; Newfoundland
• Online Access: https://doi.org/10.6084/m9.figshare.3454814.v1; https://figshare.com/articles/Laurentian_origin_of_the_Ordovician_Grangegeeth_volcanic_arc_terrane_Ireland/3454814

U–Pb ages determined by laser-ablation multi-collector inductively coupled plasma mass spectrometry on 199 zircons from a lithic pumice tuff are the first isotopic ages from the Grangegeeth volcanic terrane of Ireland. The youngest zircon population ( n = 24) yields an age of 465.4 +2.4/−3.1 Ma. Inherited zircons yield ages of c . 1120–1520, c . 1650–1914 and c . 2540–2890 Ma. The absence of zircons between c . 550 and 700 Ma argues against involvement of Avalonia as a source of inherited crystals. Overall, the inherited age spectra are characteristic of Laurentian crust or metasedimentary successions of peri-Laurentian provenance. These findings suggest that the Grangegeeth volcanic terrane does not represent a continuation of the intra-Iapetus Exploits arc of Newfoundland.