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TitleNew insights into the bedrock and Quaternary geology of St. George's Bay from a vertical integration of marine datasets, offshore western Newfoundland
AuthorDafoe, L T; Shaw, J; Jauer, C; Giles, P S; Waldron, J W F; Potter, D P
SourceBulletin of Canadian Petroleum Geology vol. 64, no. 1, 2016 p. 1-23,
Alt SeriesEarth Sciences Sector, Contribution Series 20150249
PublisherCanadian Society of Petroleum Geologists
Mediapaper; on-line; digital
File formatpdf; html
ProvinceEastern offshore region; Newfoundland and Labrador
NTS11O/14; 11O/15; 12B/01; 12B/02; 12B/03; 12B/06; 12B/07; 12B/08; 12B/09; 12B/10; 12B/11
AreaSt. George's Bay; Newfoundland; Port au Port Peninsula
Lat/Long WENS -59.5000 -58.2167 48.6500 47.7000
Subjectsmarine geology; regional geology; surficial geology/geomorphology; geophysics; paleontology; structural geology; bathymetry; sonar surveys; aeromagnetic surveys; magnetic anomalies; offshore wells; seismic surveys; seismic reflection surveys; drill core analyses; glaciomarine deposits; moraines; bedrock geology; sedimentary rocks; sandstones; salt deposits; palynological analyses; structural features; folds; anticlines; synclines; faults; basement geology; igneous rocks; volcanic rocks; mafic intrusive rocks; anorthosites; metamorphic rocks; orthogneisses; gneisses; paragneisses; tectonic interpretations; biostratigraphy; Maritimes Basin; Magdalen Basin; St. George subbasin; St. George's Bay A-36 Well; Codroy Group; Romaines Brook Fault; Barachois Group; Anguille Group; Indian Head Complex; halokinesis; multibeam bathymetry; Proterozoic; Phanerozoic; Cenozoic; Quaternary; Paleozoic; Carboniferous; Precambrian
Illustrationsgeological sketch maps; location maps; stratigraphic correlations; geophysical images; seismic reflection profiles; well logs; profiles; photographs; seismic profiles
ProgramFrontier basin analysis, Geoscience for New Energy Supply (GNES)
Released2016 06 03
AbstractSt. George's Bay lies south of Port au Port Peninsula on the west coast of Newfoundland, Canada. The Carboniferous Bay St. George subbasin extends beneath the bay and onshore to the southeast. The subbasin is an extension of the Magdalen Basin, a Carboniferous basin with probable resource potential, part of the broader Maritimes Basin. The onshore geology of the subbasin is relatively well understood. Marine datasets from the less well known offshore portion include high-resolution bathymetry, aeromagnetic data, shallow and industry wells, and both shallow and deeper (conventional) two-dimensional seismic data. Quaternary features were previously documented in inner St. George's Bay where the surficial cover is thick. In the outer part of the bay, bedrock ridges are draped by iceberg-turbated glaciomarine mud and moraines. Beneath this cover, reinterpreted palynological analyses in the A-36 well reflect only Viséan Codroy Group. The uppermost Codroy Group of this well may correlate with nearby red sandstones from shallow marine bedrock drill cores; however, younger Carboniferous rocks may also be present. Reflectors mapped using conventional seismic data mark the base Codroy Group and the top of a salt unit in the Codroy Group. Salt-cored anticlines and synclines are associated with halokinesis, and with a fault system with both dip-slip and dextral-slip components. Multibeam bathymetry and the second vertical derivative of the magnetic field delineate the folds as curvilinear, en echelon, and, in some cases, doubly plunging. Beneath the subbasin, seismic and aeromagnetic data indicate Proterozoic basement blocks and an offshore extension of the early Paleozoic Romaines Brook Fault. The Carboniferous structures suggest an environment of dextral transtension that reactivated early Paleozoic structures aligned with pre-existing weaknesses in basement.
Summary(Plain Language Summary, not published)
Western Newfoundland is an area of ongoing exploration activit. St. George's Bay lies along the southeast tip of the Island of Newfoundland separating onshore outcrops of Paleozoic rocks to the northwest from Carboniferous rocks to the southeast. This study provides insight into the offshore bedrock geology within St. George's Bay by utilizing a vertical data integration methodology combining: multibeam bathymetry, shallow seismic, industry seismic, well data, and aeromagnetic data. By integrating datasets we are able to further understand the Quaternary (surficial) geology, nature of the Carboniferous rocks and their deformation history, and basement rocks and related faults. The methodology is tested in the inner versus outer parts of the bay to show the impact of thick glacial sediments on a vertical data integration approach. In addition, seismic mapping shows that limited Anguille Group rocks are likely present beneath the bay, which suggests a low potential for source rocks in the offshore of St. George's Bay.