Sedimentological and geochemical characteristics of upper Cretaceous and lower Tertiary sediments of ODP Hole 108-661A


Autoria(s): Stein, Ruediger; Faugeres, Jean-Claude
Cobertura

LATITUDE: 9.446800 * LONGITUDE: -19.386100 * DATE/TIME START: 1986-03-17T19:15:00 * DATE/TIME END: 1986-03-20T19:15:00

Data(s)

20/10/1989

Resumo

Based on sedimentological and geochemical data, the Upper Cretaceous and Tertiary sequence at Ocean Drilling Program Site 661 was subdivided into four intervals: Interval I (Campanian age) is characterized by sediments deposited below the calcite compensation depth (CCD) inside a high-productivity area and well-oxygenated bottom waters, indicated by the absence of carbonate, the major occurrence of zeolites and opal-CT, and intense bioturbation. Very fine-grained siliciclastic sediments and the lack of any erosional features suggest a low-energy environment. The terrigenous fraction was probably supplied by winds from the nontropical areas in South Africa. Interval II (Maestrichtian age) is characterized by high-amplitude variations in the carbonate content indicative of a deposition above the CCD, superimposed by (climate-controlled) short-term fluctuations of the CCD. The absence of both zeolites and opal-CT imply a position of Site 661 outside high-productivity areas. The first occurrence of higher amounts of kaolinite (especially during the middle Maestrichtian) suggests the onset of a terrigenous sediment supply from tropical areas. Interval III (between uppermost Cretaceous to early Tertiary) is characterized by the absence of carbonate and zeolites, interpreted as deposition below the CCD and outside an oceanic high-productivity belt. The kaolinite-over-illite dominance suggests a terrigenous sediment supply from tropical areas. Interval IV (between early Tertiary and Miocene age) is characterized by the occurrence of black manganeserich layers, major nodules/pebbles, and erosional surfaces, indicating phases of extremely reduced sediment accumulation and bottom-current activities. In the lower part of this interval (?Eocene age), higher amounts of zeolites occur, which suggest a higher oceanic productivity caused by equatorial upwelling. The source area of the terrigenous sediment fraction at Site 661 was the tropical region of northwest Africa, as suggested by the kaolinite-over-illite dominance.

Formato

application/zip, 2 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.746554

doi:10.1594/PANGAEA.746554

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Stein, Ruediger; Faugeres, Jean-Claude (1989): Sedimentological and geochemical characteristics of the Upper Cretaceous and Lower Tertiary sediments at Site 661 (eastern equatorial Atlantic) and their paleoenvironmental significance. In: Ruddiman, W; Sarnthein, M; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 108, 297-309, doi:10.2973/odp.proc.sr.108.135.1989

Palavras-Chave #<2 µm, >9 phi; >63 µm; 108-661A; CaCO3; Calcium carbonate; Depth; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Halite (Intensity, 1.99 Å); Hl I 1.99 Å; Ill I 10Å; illite/mic; Illite (Intensity, 10Å); Joides Resolution; Kaolinite/(Kaolinite+Illite) ratio; Kaolinite+Chlorite (Intensity, 7.1Å); Kln/(Kln+Ill); Kln+Chl I 7.1Å; Label; Leg108; Median; Median, grain size; North Atlantic Ocean; Ocean Drilling Program; ODP; ODP sample designation; Opal-CT/Halite ratio; Opal-CT/Hl; Opal-CT (Intensity, 4.04-4.10 Å); Opal-CT I 4.04-4.10 Å; Quartz/Halite ratio; Quartz (Intensity, 4.26 Å); Qz/Hl; Qz I 4.26; Sample code/label; Size fraction < 0.002 mm, > 9 phi, clay; Size fraction > 0.063 mm, sand; X-ray diffraction; Zeo/Hl; Zeo I 8.9-9.91 Å; Zeolite/Halite ratio; Zeolite (Intensity, 8.9-9.91 Å)
Tipo

Dataset