Mid-Tertiary changes in deep ocean circulation patterns in the Natal Valley and Transkei basin, Southwest Indian Ocean

Zvi Ben-Avraham, Tina M. Niemi, Chris J.H. Hartnady

Research output: Contribution to journalArticlepeer-review

Abstract

At the critical connection between the Atlantic and Indian Oceans around South Africa, changes in bottom topography may affect global oceanic circulation. A seismic reflection survey of the basins off the coast of southeast Africa provides evidence from active and buried contourite drifts for a change in the pattern of bottom currents. A geostrophic current, which flowed in the Oligocene along the southeast African continental margin, now flows eastward in the Transkei basin. We attribute the dramatic shift in location of the contourite drift to a sudden change in bottom-water circulation caused by tectonic elevation of the Mozambique Ridge. The tectonic control of this ocean gateway are likely to have had profound effects on Indian-Pacific and Atlantic Ocean thermohaline circulation and hence local climate.

Original languageEnglish
Pages (from-to)639-646
Number of pages8
JournalEarth and Planetary Science Letters
Volume121
Issue number3-4
DOIs
StatePublished - Feb 1994

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