Seismic stratigraphy and geologic history of the Rio Grande Gap and southern Brazil Basin ( DSDP, Leg 72).

Abstract

The sedimentary evolution of the Rio Grande Gap and S portion of the Brazil Basin has been reconstructed by the analysis of single-channel and multichannel seismic reflection profiles. Conspicuous erosional and depositional episodes identified from the seismic records are dated by cores recovered from Site 515 located of the Vema Channel. A major erosional event, marked by a 22-Ma hiatus, occurred between the early Eocene and middle Oligocene. This erosional event is tentatively associated with the initiation of the flow of Antarctic Bottom Water (AABW) through the Rio Grande Gap and into the Brazil Basin.-from Authors