Sedimentary facies, clay mineralogy and geochemistry of the Paleogene sediments of ODP Site 105-647

DOI

Claystones immediately overlying the early Eocene age ocean-floor basalt, cored at Ocean Drilling Program (ODP) Site 647, underwent hydrothermal and thermal alterations originating from the basalt, which resulted in changes in both the mineralogical and chemical composition of the sediments. Chlorites and higher magnesium and iron concentrations were found in the lowermost sediment sequence. Upcore, changes in the bulk chemical composition of the sediments become smaller, when compensated for variations in the carbonate content originating from biogenic and authigenic components. Chlorite disappears upcore, but still only part of the swelling clay minerals have survived the thermal influence. Thirty meters above the basalt, the clay mineralogy and chemical composition become uniform throughout the Paleogene section. Iron-rich smectites (i.e., nontronitic types), totally dominate the clay mineral assemblage. Biogenic components, responsible for the dominant part of the calcite and cristobalite contents, vary in amount in the upper part, and so do the authigenic carbonate and sulfide contents. Detrital components, such as kaolinite, illite, quartz, and feldspars, make up a very small proportion of the sediment record. The nontronitic smectites are believed to be authigenic, formed by a supply of iron from the continuous formation of ocean-floor basalt in the ridge area that reacted with the detrital and biogenic silicates and alumina silicates.

Supplement to: Nielsen, Ole Bjorslev; Cremer, Michel; Stein, Ruediger; Thiébault, Francois; Zimmerman, Herman (1989): Analysis of sedimentary facies, clay mineralogy, and geochemistry of the Paleogene sediments of Site 647, Labrador Sea. In: Srivastava, SP; Arthur, M; Clement, B; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 105, 101-110

Identifier
DOI https://doi.org/10.1594/PANGAEA.745194
Related Identifier https://doi.org/10.2973/odp.proc.sr.105.116.1989
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.745194
Provenance
Creator Nielsen, Ole Bjorslev; Cremer, Michel; Stein, Ruediger ORCID logo; Thiébault, Francois; Zimmerman, Herman
Publisher PANGAEA
Publication Year 1989
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 6 datasets
Discipline Earth System Research
Spatial Coverage (-45.262 LON, 53.331 LAT); South Atlantic Ocean
Temporal Coverage Begin 1985-10-15T00:00:00Z
Temporal Coverage End 1985-10-25T00:00:00Z