Schematic stratigraphic distribution of Upper Triassic and Lower to Middle Jurassic strata in the Scotian Basin, showing stratigraphic setting of the studied samples. Reference stratigraphic column from OETR (2011); sources for specific regions and wells are discussed in the text. Onset of seafloor spreading from Sibuet et al. (2012). 

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... Mohican Formation is a predominantly clastic suc- cession that unconformably overlies rift-related basalt, salt, and terrigenous redbeds of Late Triassic and earliest Juras- sic age (Wade and MacLean 1990; Fig. 2). The lower part of the formation passes laterally into Iroquois Formation dolos- tones. The Mohican and Iroquois formations were interpreted as of Sinemurian to Bajocian age by Wade and MacLean (1990). However, recent biostratigraphy carried out for the Play Fairway Analysis in the Bonnet P-23 and Glooscap C-63 wells places these ...

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... Scotian Basin ( Fig. 1) is a passive-margin sedimentary basin beneath the continental shelf and slope off Nova Scotia, eastern Canada. It formed during the Late Triassic rifting and Early Jurassic separation of the North American and African plates (Wade and MacLean 1990). The infill sequences of the initial rift subbasins are characterized by interbedding of clastic fluvial-deltaic strata with some Late Triassic evaporite and carbonate strata. Within the Mesozoic, the Jurassic Mohican and Mic Mac formations and Lower Cretaceous Missisauga and Logan Canyon formations consist mainly of sandstone and shale, deposited during periods of high terrigenous sediment supply (Wade and MacLean 1990). The Mohican Formation is a predominantly clastic suc- cession that unconformably overlies rift-related basalt, salt, and terrigenous redbeds of Late Triassic and earliest Jurassic age (Wade and MacLean 1990; Fig. 2). The lower part of the formation passes laterally into Iroquois Formation dolos- tones. The Mohican and Iroquois formations were interpreted as of Sinemurian to Bajocian age by Wade and MacLean (1990). However, recent biostratigraphy carried out for the Play Fairway Analysis in the Bonnet P-23 and Glooscap C-63 wells places these formations within the Callovian to possibly late Bathonian (Weston et al. 2012), consistent with the Ba- thonian–Callovian age determined in the Georges Bank Basin (Poppe and Poag 1993). Wells penetrate the Mohican Formation only at its thin inboard edge: it is 250 m thick at the type section in the Oneida O-25 well and 400 m thick at the Glooscap C-63 well. Seismic profiles show that the Mohican Formation thickens in grabens inherited from the Late Triassic rifting. Beneath the depth penetrated by the Mic Mac H-86 well, seismic profiles show there is a prominent regional unconformity within the Mohican Formation (Wade and MacLean 1990). The maximum thickness of the Mohican Formation based on seismic interpretation, over 5.5 km, is found in the Laurentian Subbasin (MacLean and Wade 1992). Previous work on the provenance of the Mohican Formation is restricted to muscovite and feldspar geochronology on three samples from the Mic Mac H-86 well, which yielded ages of 275–360 Ma (Grist et al. 1992). These ages are similar to those found for detrital muscovites in Lower Cretaceous sandstones of the Sable Subbasin. Reynolds et al. (2009) interpreted this muscovite to have been derived from the Meguma terrane metasedimentary rocks on the present inner shelf that were metamorphosed in the Alleghanian orog- eny in the Late Carboniferous – Early Permian (Pe-Piper and Jansa 1999). Detailed petrographic study requires uncontaminated samples from conventional core. Only three wells in the Scotian Basin recovered short conventional cores from the Mohican Formation. They are the Wyandot E-53 and Mic Mac H-86 wells located at the northern edge of the Abenaki Subbasin adjacent to the Canso Ridge south of Cape Breton Island, and the Mohican I-100 well at the eastern end of the Shelburne Subbasin (Figs. 1, 3). No samples of the Mohican Formation are available from the eastern part of the Scotian Basin east of Wyandot E-53. In each well, the conventional core is within 200 m of the top of the formation. Rock samples were cut into centimetre-size chips, and gently crushed with a pestle and mortar until all grains had passed through a 0.5 mm sieve. The 63–180 ␮ m fractions were sieved and separated by using an aqueous solution of sodium polytungstate with a density of 2.9 g/cm 3 . Polished thin sections of heavy minerals were prepared for mineral abundance (modal) analysis and electron microprobe chemical analysis. The scanning electron microscope (SEM) at the Regional Analytical Centre at Saint Mary’s University was used to identify the heavy minerals by energy dispersive spectros- copy (EDS). All the minerals in random fields of view were identified and counted (Table 1), for a target total of at least 300 grains. Criteria for mineral identification were texture and backscattered electron (BSE) intensity, confirmed, where nec- essary, by an EDS spectrum. Reproducibility is good, based on the comparison of data from one mount of a heavy mineral separation and one whole-rock thin section from the same sandstone sample at Mohican I-100 (Table 1). BSE images were taken for the morphologic analysis of some minerals. Located grains of tourmaline, garnet, feldspar, and xenotime were analyzed at the Regional Electron Microprobe Centre at Dalhousie University for quantitative chemical composition. Analyses were made using a JEOL-8200 electron microprobe with five wavelength dispersive spectrometers and a Noran 133 eV energy dispersion detector. The beam was operated at 15 kV and 20 nA, using a beam diameter of about 1 ␮ ...