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.
1966; Watkins and Boucot 1975) suggest these blocks were once part of a composite marine depocentre, referred to as the Mascarene Basin by Fyffe et al.
This fault divides the Mascarene Basin into two domains that possess distinctive stratigraphies and structural styles.
Silurian strata underlying the Mascarene Basin on the northwestern side of the Saint George Batholith appear to form a continuous, homoclinal sequence facing to the southeast (Fyffe et al.
The northwestern margin of the Mascarene Basin in this region is defined by the Sawyer Brook Fault, which separates the Oak Bay Formation, a 600 in-thick sequence of polymictic conglomerate and sandstone, from Early Ordovician black shale of the Cookson roup (Fig.
The southeastern parts of the Mascarene Basin comprise a series of narrow fault blocks of Precambrian basement, commonly separated by slices of Paleozoic strata.
George Fault in order to investigate the age relationships between these disparate parts of the Mascarene Basin.
The Addison conglomerate with a thickness of 900 m (Gates 1989) at the base of the Silurian sequence in coastal Maine, and conglomerate of the Oak Bay Formation with a thickness of 600 m beneath the Waweig Formation in New Brunswick may represent contemporaneous debris flows marking the initiation of rifting along the northwestern part of the Mascarene Basin.
A much shallower water to subaerial volcanic and sedimentary sequence occurs within the Mascarene Basin of New Brunswick between the Saint George Batholith to the northwest and the Saint George Fault to the southeast.