Paleogeography of the Mesozoic Jeanne d'Arc Basin, Grand Banks, Newfoundland, Canada

MCCRACKEN, JOCK N., Mobil Oil Canada, Calgary, Alberta, Canada

The major stratigraphic sequences of the Jeanne d'Arc basin, Grand Banks, offshore Newfoundland, Canada, and their relationship to the tectonic events involved in the opening of the North Atlantic are summarized. This basin has been a major exploration area for Mobil and industry since 1971. This activity has resulted in the shooting of over 300,000 km of reflection seismic lines and the drilling of 65 wells. Fifteen discoveries have been found in the basin to date by industry. The Hibernia project is underway with production planned in 1996. Government basin analysis estimates for total ultimate recoverable reserves in the Jeanne d'Arc basin range from 3.3 to 10 billion bbl of oil equivalent.

The major stratigraphic events from the Late Jurassic to the Early Eocene within the Jeanne d'Arc basin are illustrated by six isometric paleogeographic reconstructions. These geological sequences are then related on the stratigraphic column to the tectonics and coastal onlap curves. During the Late Jurassic/Early Cretaceous syn-rift phase three regressive pulses of predominantly deltaic sediments (Jeanne d'Arc, Hibernia, and Avalon formations) prograded into the Jeanne d'Arc basin from the southwest with minor sediment contributions from the eastern and western perimeter highs. During Aptian time the Grand Banks separated from the Galicia Bank of Iberia creating a major transgression that flooded the basin and reworked the existing clastics (Ben Nevis Formation). At the end of Albian during the breakup of the Flemish Cap and the Goban Spur, thermal subsidence initiated a prolonged transgression that was only interrupted by local regressions. A relative drop in sea level in the lower Eocene/Paleocene then triggered submarine fan deposition (Topsail and Mara Formations) sourced from the west.

The major controls on Jeanne d'Arc basin deposition were the tectonics created as a result of the northward propagation of the rifting of the Atlantic Ocean and its effect locally on the broad arch to the south called the Avalon Uplift. This provided the major clastic source throughout the Mesozoic. Changes in relative sea level then overprinted these tectonic events.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)