Skip to Main Content

Abstract

Seismic reflection data collected as part of the Brazilian Continental Shelf Survey has allowed the recognition of large sediment drifts related to bottom currents along the continental rise off northeastern Brazil. Antarctic Bottom Water (AABW), which flows northward across a physiographic constriction - the hotspot-related Bahia Seamounts - has controlled the deposition of these contourite drifts. Following this pathway since the Middle Oligocene, AABW has also led to the formation of regional unconformities and the excavation of the 800 km long and up to 470 m deep Pernambuco Seachannel. This feature, which represents the ‘trunk channel’ of a complex submarine drainage system, flows into the Pernambuco Abyssal Plain, building a large fan-like deposit - the Pernambuco Countourite Fan. As observed elsewhere along continen–tal margins, the geometry of the sediment drifts alternates from mounded to sheeted, channel-related or confined, depending on the physiographic setting and on the velocity of the flow. The so-called 'modified drift-turbidite systems', formed by an interplay between downslope sediment gravity flows and alongslope bottom-current-controlled deposition, are well developed near the continental slope region, particularly in the Sergipe Basin, where the São Francisco River has built its deep-sea fan.

You do not currently have access to this chapter.

Figures & Tables

Contents

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal