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The AAPG/Datapages Combined Publications Database

CSPG Special Publications


Arctic Geology and Geophysics: Proceedings of the Third International Symposium on Arctic Geology — Memoir 8, 1982
Pages 279-295

Bedrock Structures Off Cumberland Sound, Baffin Island Shelf: Core Sample and Geophysical Data

B. MacLean, S. P. Srivastava, R. T. Haworth


Seismic reflection profiles reveal four ridge structures that trend northeast-southwest along the Baffin Island shelf offshore from Cumberland Sound in the northern Labrador Sea-Davis Strait region. Recent shallow core drill samples indicate the presence of petroliferous and gassy late Paleocene-early Eocene mudstone at one ridge and volcanic rocks and early Eocene strata at another. Samples of late Albian-Cenomanian sandstone obtained previously near the first of these localities suggest that rocks at least as old as middle Cretaceous also occur locally at the bedrock surface in these structures. Modelling of seismic, gravity, and magnetic data suggests that volcanic and sedimentary rocks are components of each of the ridge structures. Two of the structures resemble piercement features on seismic profiles. The ridges mainly lie within the area of a large positive gravity anomaly. This is bounded to the west by a large negative gravity anomaly.

Emplacement of the volcanics is believed to have occurred along major fractures developed as a consequence of rotational and translational motion between Greenland and North America in early Tertiary time. Massive dykes formed by introduction of the volcanic material are the probable cause of the structures. Sedimentary diapirism, if involved, more likely is confined to the westernmost ridge adjoining the gravity low.

Movement on the structures apparently was not complete until after early Eocene time. Subsequently the region was extensively bevelled by erosion.

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