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The extreme straightness of Nares Strait has led several authors to suggest that a major fault runs through the strait, possibly the result of northeastward movement of Greenland relative to Canada. As Lancaster Sound resembles other known aulacogens, and Baffin Bay has been shown to be floored by oceanic crust, it is possible that Nares Strait is the third arm of a RRF triple junction.

Both new and published marine geophysical data have been used to produce detailed bathymetry and free air gravity contour maps of the southern termination of Nares Strait, here termed North Water Bay. These data, together with an aeromagnetic contour map (based on data provided by Hood, 1974), and seismic reflection data reveal several significant sedimentary basins. These roughly parallel major fault and graben systems seen onshore. A possible basalt-filled fracture off southeastern Ellesmere Island may extend norhtwards as a linear sediment-filled feature.

From a study of the land geology literature, detailed geology and structure maps covering the region from north Baffin Island to Northeast Greenland have been produced. A number of possibly important markers and structural features were revealed. The correlation of these features across Nares Strait suggests that movement along the strait of a minimum of 200 km has occurred since the mid-Paleozoic, and a maximum of 300 km since late Precambrian times. It seems probable that such movement occurred in a number of spurts, beginning with rifting in the Proterozoic and ending in the Tertiary orogeny.

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Supervisor: R.K.H. Falconer