Neogene Sand Layers off Northwest Africa: Composition and Source Environment

Sarnthein, Michael

doi:10.2973/dsdp.proc.38394041s.408.1978

Cited by 11 publications

(16 citation statements)

References 15 publications

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“…Off northwest Africa it is inferred from the onset of coastal upwelling and deposition of eoliansand turbidites since 2.5 m.y. to the beginning of numerous periods of accentuated glacial-style meridional trade winds (Sarnthein, 1977;Sarnthein et al, 1982).…”

Section: Pliocenementioning

confidence: 99%

Nannoplankton Biostratigraphy and Paleoenvironmental Interpretations from the Tyrrhenian Sea, ODP Leg 107 (Western Mediterranean)

Müller¹

1990

Proceedings of the Ocean Drilling Program

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This paper summarizes the nannoplankton biostratigraphy and the paleoenvironmental interpretations obtained from Leg 107 in the Tyrrhenian Sea. Marine sediments are ranging in age from late Tortonian to Recent.The Mediterranean as a semiclosed adjacent sea of the Atlantic is strongly controlled by paleoceanographic changes in the Atlantic which are related to the global climatic evolution. This influence of the Atlantic is more pronounced in the western than in the eastern Mediterranean. The occurrence of sapropels and sapropelic layers also in the western Mediterranean was shown for the first time.

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Section: Pliocenementioning

confidence: 99%

Nannoplankton Biostratigraphy and Paleoenvironmental Interpretations from the Tyrrhenian Sea, ODP Leg 107 (Western Mediterranean)

Müller¹

1990

Proceedings of the Ocean Drilling Program

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“…Eolian-sand turbidites with ages between ~12 and 11 Ma are noted at DSDP Sites 397 and 140 (Sarnthein, 1978;Sarnthein and Diester-Haass, 1977;Arthur et al, 1979;Sarnthein et al, 1982). At Sites 955 and 956, turbidite depositional rates are low approximately during this same time period, with most of the turbidites being mixtures of foraminifers, quartz, and volcanic lithic fragments.…”

Section: Middle Miocene (166−112 Ma)mentioning

confidence: 93%

“…Sedimentologic and provenance variations of coarse-grained units in the deep marine environment therefore provide an important tool in interpreting the depositional processes and their possible relationship to sea-level changes on the adjacent continental margin (e.g., Berger and von Rad, 1972;Sarnthein and Diester-Haas, 1977;Sarnthein, 1978;Arthur et al, 1979;Chamley and Diester-Haas, 1979;Sarnthein et al, 1982;Auffret et al, 1984;Faugeres et al, 1989;Tiedemann et al, 1989;Tiedemann et al, 1994). …”

Section: Introductionmentioning

confidence: 99%

“…During a sea-level fall, such as during a glacial period, much of the continental shelf is exposed, allowing eolian sands from the Sahara Desert to migrate farther seaward to the new shelf edge (Sarnthein and Diester-Haass, 1977;Sarnthein, 1978;Chamley and Diester-Haass, 1979;Auffret et al, 1984;Faugeres et al, 1989;Tiedemann et al, 1989). As a result, during sea-level lowstands or as sea levels are rising or falling, there should be an increase in the frequency of quartz-rich turbidites being shed off the continental shelf into the deep marine environment.…”

Section: Introductionmentioning

confidence: 99%

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Provenance and sedimentologic variations of turbidite and slump deposits at Sites 955 and 956

Goldstrand¹

1998

Proceedings of the Ocean Drilling Program, 157 Scientific Results

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At two of the seven sites drilled during Leg 157, located south of the Canary Islands (Sites 955 and 956), more than 1000 thinly bedded to finely laminated volcaniclastic and nonvolcaniclastic silt and sand turbidite units interbedded within thick sequences of hemipelagic mud were recovered. The sediments range in age from Pleistocene to middle Miocene. Turbidite deposits composed mostly of volcaniclastic detritus are related to known periods of volcanism in the Canary Islands. The nonvolcaniclastic turbidites include various mixtures of quartz and foraminifer sand and silt derived from the continental margin of northwestern Africa. Shallow marine bioclastic deposits are thicker at Site 956 than at Site 955, suggesting that these sediments were derived from the southern Canary Islands.Although age constraints cannot be precisely defined at these sites, the general trend of sedimentation is consistent with sealevel variations being responsible for transport of the continentally derived turbidites. Quartz-rich turbidite deposits composed of well-rounded, very fine-grained sand were derived from Saharan eolian sands that migrated onto the subaerially exposed continental shelf and were shed into the deep marine environment during falls in sea level. Shallow marine bioclastic and foraminifer-rich turbidites also correspond to periods of sea-level fluctuations. However, the presence of volcaniclastic material within several bioclastic deposits indicates volcanic activity may have been responsible for some of their deposition.Large-scale submarine slumping appears to be more active during periods of intensified bottom currents and upwelling. Additionally, slumping was more frequent at Site 956 on the lower flank of Gran Canaria. Slump block ages are only slightly older than those of the surrounding sediment, and mass movement may have resulted from increased sedimentation and/or earthquakes associated with Canary Islands volcanism.

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“…Sarnthein's (1978) map of the global distribution of sand seas appears in Tchakerian's chapter -two decades of Quaternary research have put this one well beyond its sell-by date. This chapter also contains more typographic errors than the rest of the book put together, though none of the quality of that on page 66, where 'climatic chaos' has been substituted for 'climatic change'.…”

mentioning

confidence: 99%

THE ROLE OF EROSION AND SEDIMENT TRANSPORT IN NUTRIENT AND CONTAMINANT TRANSFER edited by M. Stone, International Association of Hydrological Sciences Publication 263, IAHS Press, Wall‐ingford, 2000. No. of pages: 307. Price: £48.00. ISBN 1 901502 26 0.

Burt

2001

Earth Surf Processes Landf

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Neogene Sand Layers off Northwest Africa: Composition and Source Environment

Cited by 11 publications

References 15 publications

Nannoplankton Biostratigraphy and Paleoenvironmental Interpretations from the Tyrrhenian Sea, ODP Leg 107 (Western Mediterranean)

Nannoplankton Biostratigraphy and Paleoenvironmental Interpretations from the Tyrrhenian Sea, ODP Leg 107 (Western Mediterranean)

Provenance and sedimentologic variations of turbidite and slump deposits at Sites 955 and 956

THE ROLE OF EROSION AND SEDIMENT TRANSPORT IN NUTRIENT AND CONTAMINANT TRANSFER edited by M. Stone, International Association of Hydrological Sciences Publication 263, IAHS Press, Wall‐ingford, 2000. No. of pages: 307. Price: £48.00. ISBN 1 901502 26 0.

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