Site 369: Continental Slope off Cape Bojador, Spanish Sahara

Party, Bukry The Shipboard Scientific

doi:10.2973/dsdp.proc.41.105.1978

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Minor fragmentation of planktonic foraminifers at the Sierra Leone Rise (Site 366; corresponds to evidence of a generally deep CCD (Berger and von Rad, 1972;van Andel, 1975;Thiede et al, 1980). Intensified coastal and equatorial upwelling comparable to that of the glacial regimes, and a resulting strong oxygen-minimum layer on the upper slope are inferred from the biogenic opal deposits in Site 140,366,368,369,and 397, from maximum rates of sediment accumulation under the equator (Site 366) (pflaumann, in Lancelot and Seibold, 1978), from reworked shallow-water fauna characteristic of cool-temperate tempera-tures (Sarnthein, 1978b) and finally, from large amounts of organic-rich mudstones at Sites 369 and 397 (Shipboard Scientific Party, 1978. They derive from mass flows which originated in an oxygen-depleted zone along the upper slope (Arthur et al, 1979).…”

Section: Evolution Of Neogene Paleoenviron-mentsmentioning

confidence: 99%

Atmospheric and Oceanic Circulation Patterns off Northwest Africa During the Past 25 Million Years

Sarnthein

Thiede

Pflaumann

et al. 1982

Geology of the Northwest African Continental Margin

252

208

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Section: Evolution Of Neogene Paleoenviron-mentsmentioning

confidence: 99%

Atmospheric and Oceanic Circulation Patterns off Northwest Africa During the Past 25 Million Years

Sarnthein

Thiede

Pflaumann

et al. 1982

Geology of the Northwest African Continental Margin

252

208

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Analysis of geological hiatus surfaces across Africa in the Cenozoic and implications for the timescales of convectively-maintained topography

2019

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Geological maps are a powerful but underutilized tool for constraining geodynamic processes and models. Unraveling the Cenozoic elevation history of Africa and distinguishing between competing uplift and subsidence scenarios is of considerable interest to constrain the dynamic processes in the mantle beneath the continent. Here, we explore continental-scale geological maps, and map temporal and spatial patterns of geological contacts, assuming that interregional-scale unconformable contacts (hiatus surfaces) on geological maps yield proxy records of paleotopography and vertical motion. We found that significant differences in the spatial extents of interregional-scale hiatus surfaces exist across Africa at the timescale of geologic series. A significant expansion of total unconformable area at the base of the Miocene strongly suggests that the Oligocene was a period of uplift in most of Africa. In southern Africa there is a complete absence of marine sediments in both the Oligocene and Pleistocene. This pattern suggests that southernmost Africa reached a high elevation in the Oligocene, subsided in the Miocene–Pliocene, and has been high again since the latest Pliocene or Pleistocene. Our hiatus mapping results support a dynamic origin of Africa’s topography. In particular, they point to elevation changes at the timescale of geologic series (ten to a few tens of millions of years), which is considerably smaller than the mantle transit time. The timescale for elevation changes in Africa is, thus, comparable with the rapid spreading in the South Atlantic, which have been geodynamically linked to African elevation changes through pressure-driven upper mantle flow.

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Site 369: Continental Slope off Cape Bojador, Spanish Sahara

Cited by 2 publications

References 5 publications

Atmospheric and Oceanic Circulation Patterns off Northwest Africa During the Past 25 Million Years

Atmospheric and Oceanic Circulation Patterns off Northwest Africa During the Past 25 Million Years

Analysis of geological hiatus surfaces across Africa in the Cenozoic and implications for the timescales of convectively-maintained topography

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