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TitleThe gravity anomaly field in the Ungava region of northern Quebec
AuthorTanner, J G; McConnell, R K
SourceDominion Observatory, Gravity Map Series nos. 5-6, 1964, 21 pages (3 sheets), (Open Access)
PublisherCanada Department of Mines and Technical Surveys (Ottawa, Canada)
MapsPublication contains 3 maps
Map Info.geophysical, gravity anomalies, 1:500,000
Map Info.geological, lithological, 1:433,231
Mediapaper; on-line; digital
RelatedThis publication contains the following publications
RelatedThis publication is a translation of Tanner, J G; McConnell, R K; (1965). Le champ de gravité de la péninsule d'Ungava (nord du Québec), Dominion Observatory, Gravity Map Series no. 5-6
File formatpdf
NTS24 /NW; 25 /SW; 34 /NE; 34 /NW; 35
AreaUngava Peninsula; Povungnituk; Wakeham Bay; Cape Smith
Subjectsgeophysics; regional geology; gravity surveys, ground; gravity interpretations; densities; iron formations; Cape Smith High; Cape Smith Low; Cape Smith-wakeham Bay Belt; Labrador Trough; Payne Bay High; Sugluk High; Superior Province; Precambrian
Illustrationsgravity profiles; tables; sketch maps
Released1964 01 01; 2018 11 13
AbstractDuring the summer seasons of 1959 and 1960, field parties of the Dominion Observatory made 614 regional gravity measurements in the Cape Smith-Wakeham Bay area of New Quebec. The Bouguer anomalies indicate that the area as a whole is in a state of isostatic equilibrium. A linear Bouguer anomaly correlates with the basic volcanic and intrusive rocks of the Cape Smith belt. Calculations based on observed anomalies indicate that the folded basic rocks of the belt are thicker than 20,000 feet. Negative anomalies that flank the Cape Smith positive anomaly can be explained isostatically by regarding the Cape Smith belt as a load on the crust. The thickness of the root, about 10,000 feet, calculated from the load itself agrees with that computed from the negative anomalies. A local positive anomaly in the Payne Bay area indicates the presence of a large intrusive body. The presence of a gabbroic intrusion at the surface is confirmed by rock samples. Computations based on a residual Bouguer anomaly profile across the feature suggest that the body extends to a depth of about 40,000 feet is approximately 20 miles in diameter and has a central dome a few thousand feet wide extending upward from the main body to the surface.