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TitleCorrelation of the Aptian Naskapi Member of the Scotian Basin and its regional implications
AuthorChavez, I; Piper, D J W; Pe-Piper, G
SourceCanadian Journal of Earth Sciences vol. 55, no. 5, 2018 p. 514-535, (Open Access)
Alt SeriesNatural Resources Canada, Contribution Series 20170362
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceEastern offshore region; Nova Scotia
NTS1SW; 10; 11A; 11B; 11C; 11D; 11F; 11G; 11H; 20
AreaAtlantic Ocean; Scotian Basin; Georges Bank
Lat/Long WENS -67.0000 -53.0000 46.0000 41.0000
Subjectsstratigraphy; paleontology; geochemistry; geophysics; Lower Cretaceous; Aptian; systematic stratigraphy; stratigraphic correlations; bedrock geology; lithology; sedimentary rocks; shales; black shales; sandstones; mudstones; provenance; biostratigraphy; geological history; tectonic history; volcanism; depositional history; sea level changes; well logging; gamma ray logging; heavy mineral analyses; sedimentary environments; offshore wells; lithostratigraphy; sedimentary petrology; paleodrainage; Logan Canyon Formation; Naskapi Member; Cree Member; Mississauga Formation; Cree E-35 Well; Meguma Terrane; Scotian Shelf; sonic logging; Phanerozoic; Mesozoic; Cretaceous
Illustrationslocation maps; geoscientific sketch maps; stratigraphic charts; tables; stratigraphic correlations; geophysical logs; lithologic sections; pie charts; photomicrographs; ternary diagrams; bar graphs; geochemical plots
ProgramGeoscience for New Energy Supply (GNES), Frontier basin analysis
Released2018 02 26
AbstractThe Naskapi Member of the Logan Canyon Formation, a 150 m thick shale-dominated unit, lies in between sand-dominated units of Upper Mississauga Formation below and the Cree Member above. The great decrease in sediment supply has been suggested as due to tectonic and (or) eustatic sea-level changes. Wireline logs and recent biostratigraphy of 30 wells from the Scotian Shelf and Georges Bank, mudstone geochemistry from the Naskapi and Cree Members, and modal composition and chemical variation of detrital heavy minerals in sandstones were examined to better understand the deposition of the Naskapi Member and its regional implications. Minor sandy intervals at the base of the Naskapi Member were correlated based on gamma and sonic log signatures from the type section in the Cree E-35 well to progressively more distant wells, on the assumption that the sands represent periods of lowered eustatic sea level. Correlation was confirmed by the distribution of highstand black shales in washed cuttings and biostratigraphic markers identified in some wells. The geochemistry of mudstones from the Naskapi Member resembles mudstones sourced from the Meguma Terrane, except for a higher abundance of elements likely reworked in smaller amounts from the Upper Mississauga Formation. Based on the correlation and geochemistry of mudstones and detrital minerals, we suggest the diversion of Sable River through the Gulf of St. Lawrence to either the Orphan Basin or towards western Canada was responsible for the decrease of sediment supply in the Scotian Basin during the deposition of the Naskapi Member shales.
Summary(Plain Language Summary, not published)
An thick shale unit, a seal for petroleum reservoirs in the Scotian Basin, has been correlated from Georges Bank to Laurentian Channel. It accumulated at a time when the main supply of sand to the Scotian Basin was diverted elsewhere.