Geochronology of the Letete and Waweig formations, Mascarene Group, southwestern New Brunswick
DOI :
https://doi.org/10.4138/1253Résumé
Felsic tuffs from the Letete and Waweig formations of the Mascarene Group in southwestern New Brunswick have essentially identical U-Pb ages of 437 ± 7 and 438 ± 4 Ma and were, therefore, both deposited in the Llandoverian of the Early Silurian. These radiometrically determined ages bring into question the validity of assigning Late Silurian ages to rock units in the Mascarene Basin based on the presence of Salopina sp. The new data also indicate that rate of deposition for the volcanic sequences in the Mascarene Basin of New Brunswick is similar to that of the classic sections in coastal Maine. RESUMÉ Les tufs felsiques des formations de Letete et de Waweig du groupe de Mascarene dans le Sud-Ouest du Nouveau-Brunswick ont des âges au U-Pb essentiellement identiques de 437 ± 7 et 438 ± 4 Ma; ils se sont par conséquent déposés dans les deux cas au cours du Valentien, pendant le Silurien précoce. Ces âges radiométriques remettent en question la validité de l'attribution d'âges remontant au Silurien tardif aux unités rocheuses du bassin de Mascarene basée sur la présence de l'espèce Salopina. Les nouvelles données révèlent par ailleurs que le rythme de sédimentation des séquences volcaniques dans le bassin de Mascarene au Nouveau-Brunswick est semblable à celui des sections classiques le long du littoral du Maine.Téléchargements
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