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Age of the Lough Talt and Easky adamellites in the central Ox Mountains, N.W. Ireland, and their structural significance
Author(s) -
Long C. B.,
Max M. D.,
O'Connor P. J.
Publication year - 1984
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350190406
Subject(s) - ordovician , geology , devonian , ecological succession , overprinting , sequence (biology) , paleontology , igneous rock , period (music) , metamorphic rock , ecology , genetics , physics , acoustics , biology
The Lough Talt and Easky adamellites in the north‐central Ox Mountains inlier were originally regarded as being nearly synchronous in age of emplacement with the more strongly deformed c. 480 Ma Ox Mountains granodiorite. They are now shown by Rb‐Sr whole‐rock dating to be significantly younger at c. 400 Ma. This recognition of the emplacement of late Silurian/early Devonian Newer Caledonian granites in the central Ox Mountains inlier indicates that the thermal overprinting by the adamellites of the regionally metamorphosed Ox Mountains succession is not an early Ordovician event. Earlier interpretations, using deformationai events and igneous intrusions, advanced by others to suggest that the Ox Mountains succession is pre‐Caledonian are now greatly weakened since the deformationai sequence in the Ox Mountains succession is now known to span a longer period of time, ranging from Grampian (late Cambrian to early Ordovician) to Caledonian sensu stricto , and therefore leaves fewer events to have occurred prior to the early Ordovician emplacement of the Ox Mountains granodiorite.