Abstract: Stratigraphic Development and Unconformity Generation in Actively Extending Regions: An Example from Jeanne d'Arc Basin, Offshore Newfoundland

Neal W. Driscoll, Nicholas Christie-Blick, John R. Hogg

Using seismic reflection and exploratory well data, we examined the stratigraphic response of the Jeanne d'Arc basin to Early Cretaceous extension. Jeanne d'Arc basin is a large half graben, which trends north-northeast. The border faults marking the western limit of the basin dip eastward, and are characterized by minimal overlap. The structure and geometry of the border faults and transbasinal faults engendered by Early Cretaceous extension influenced the drainage and therefore the sedimentation patterns in and around the Jeanne d'Arc basin. The stratigraphic response to extensional basin formation varies as a function of scale. The local response was controlled by the small-scale basin architecture (e.g., the interaction of border and transfer faults). At a regional scale, sediment tion was influenced by the pre-existing axial drainage networks that enter the basin along the southern basin-bounding transfer zone. Locally derived sandstones are wedge shaped, correspond with a progradational seismic reflection geometry, and downlap onto the early Aptian rift-onset unconformity. Elsewhere in the basin, the same unconformity correlates with a flooding surface between non-marine shales and onlapping marine sandstones. These sandstones, derived for the most part from the southern-most transfer zone, infilled the basin longitudinally, are more regionally persistent, and onlap onto the locally derived prograding wedge. Well data from the basin suggest that the regionally derived sediments are better sorted than those of local origin, and possibly of better reservoir qualit .

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994