Laurentian origin of the Ordovician Grangegeeth volcanic arc terrane, Ireland

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. Inh...

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Bibliographic Details
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
Description
Summary: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.

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