The Paleoenvironment and Development of the Eastern North American Continental Margin
1981
Schlee, J S | Jansa, L F
Geophysical studies (multichannel seismic reflection profiles, gravity and magnetic surveys) have been combined with drill hole data so that the major structural elements of the eastern North American continental margin and the seismic stratigraphy of the offshore sedimentary prism can be outlined. Studies of drill cores on the present shelf indicate that major marine incursions occurred during the Early and Late Middle Jurassic and culminated in the buildup of a series of carbonate platforms and banks that continued to flourish into the Albian on the Eastern Blake Plateau. Off the eastern United States, these banks appear to have formed in the vicinity of the ocean-continent boundary, and may have been associated with secondary volcanic dikes and sills which were emplaced 20-30 m.y. after continental separation. Influxes of terrigenous detritus during the Early to middle Cretaceous broadly prograded the margin as deltaic and mixed inner shelf and nonmarine deposits. A series of marine transgressions in the Late Cretaceous and early Tertiary changed the shelf to a deep-water setting and resulted in the deposition of chalks and marly shale. Major marine regressions in the Oligocene, Miocene and Quaternary contributed to periodic cutback of shelf and slope, exposure of Cretaceous and lower Tertiary strata in submarine canyons, accentuation of the shelf-slope-rise profile, and construction of a broad sedimentary prism beneath the continental rise.
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