Cretaceous strata on the Scotian Shelf

Abstract

Samples of Cretaceous sediment have been dredged from the Scotian Shelf at a locality 100 km north-northwest of Sable Island.Continuous seismic-reflection profiles across the sample area show the presence of well defined stratification within the bedrock. These beds are truncated by the slopes of submarine valleys which transect the area. Bedrock appears to outcrop along the upper portion of the valley walls or be covered by a layer of unconsolidated material so thin as to be beyond the resolution of the seismic equipment. The dredged material appears to have come from rubble heaps near the base of the valley slopes and is believed to have originated locally.Approximately 450 kg of sedimentary rock were recovered consisting principally of sideritic quartz sandstone and arenaceous sideritic carbonate, both with fossiliferous material. Glauconite is a significant constituent of many samples.The macrofauna include sufficiently diagnostic forms to suggest correlation with the early Upper Cretaceous (Cenomanian) though the possible presence of older or younger forms cannot be wholly excluded. The microflora and microfauna appear to correlate mainly with the Albian-Aptian, and Albian-Cenomanian, respectively.Cretaceous strata immediately underlie much of the central and eastern portions of the Scotian Shelf. Tertiary sediments reported by Marlowe and Bartlett overlie the Cretaceous toward the continental margin and appear to occur as a discontinuous veneer at other localities on the shelf.

Hidden Cretaceous basins in Nova Scotia

“…Greenough (1995, p. 586) linked the Fundy Basin deformation with the Orpheus Graben offshore, an eastward continuation of the Cobequid Fault system (Fig. In the Orpheus Graben, evidence of early-mid Cretaceous diastrophism includes volcanism and a major mid-Cretaceous (Avalon) unconformity (King et al 1970;Jansa and Pe-Piper 1988). In the Orpheus Graben, evidence of early-mid Cretaceous diastrophism includes volcanism and a major mid-Cretaceous (Avalon) unconformity (King et al 1970;Jansa and Pe-Piper 1988).…”

Cretaceous Biostratigraphy of the Grand Banks of Newfoundland

“…The mid-Tertiary biostratigraphy of the Scotian Shelf was described by Bartlett (1968). Middle Cretaceous strata obtained in dredge hauls on the Scotian Shelf were reported by King et al (1969). Cushman (1936) recorded Cretaceous foraminifera in greensands from Georges Bank.…”

Some Techniques and Applications of Scanning Electron Microscopy in the Fields of Marine Science

“…An example of the use of the S. E. M. to resolve the mineralogy of a minor constituent in a marine carbonate rock is illustrated by figures 7 and 8. This particular specimen had been examined as a thin section on a polarizing petrographic microscope and was observed to be a carbonate cemented sandstone (King et al 1970). A powdered sample of the same material when analysed by X-ray diffraction was found to contain about 15% apatite [CagfF, CI) (P04)3] minerals, although no apatite minerals could be seen in thin sections of the sample.…”