Laurentian origin of the Ordovician Grangegeeth volcanic arc terrane, Ireland
Brian McConnell
Quentin G. Crowley
Nancy Riggs
10.6084/m9.figshare.3454814.v1
https://geolsoc.figshare.com/articles/dataset/Laurentian_origin_of_the_Ordovician_Grangegeeth_volcanic_arc_terrane_Ireland/3454814
<p>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
(<em>n</em> = 24) yields an age of 465.4 +2.4/−3.1 Ma. Inherited zircons yield ages of <em>c</em>. 1120–1520, <em>c</em>. 1650–1914 and <em>c</em>. 2540–2890 Ma. The absence of zircons between <em>c</em>. 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.
</p>
2016-06-21 12:22:13
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
Geology