Abstract

Industrial multichannel seismic data show a series of elongate sedimentary basins beneath the outer continental shelf east of Newfoundland. The basin sediments range in age from Carboniferous to Early Cretaceous; regional subsidence since the Late Cretaceous buried these basins under Cenozoic sediments. The underlying basement is composed of Precambrian and Paleozoic rocks of the Appalachian orogen. Seismic data show that the flanks of the basins are primarily erosional surfaces that record uplift followed by subsidence; in places total displacement exceeds 10 km. The development of these basins can be reasonably explained in terms of recurrent vertical displacements (inversion tectonics); it does not appear that these movements involved significant crustal extension.

The central segment of the series of basins coincides with a pronounced, positive shelf-edge gravity anomaly. It reflects an underlying dense body, presumably related to basin formation. If this is a typical shelf-edge gravity anomaly, it suggests that similar anomalies elsewhere may also indicate inversion tectonics.

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