Mineralogy of Quaternary Sediments from the Vema Fracture Zone Valley (Central Atlantic)

The content of sediment-forming minerals in two cores from the eastern (ANS45-37) and western (ANS45-48) parts of the valley of the Vema Fracture Zone is studied using semiquantitative XRD analysis of bulk powder sediment samples. The mineral composition of deep-sea sediments from the Amazone Cone i...

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Bibliographic Details
Published in:Oceanology (Washington. 1965) 2024-02, Vol.64 (1), p.37-55
Main Authors: Murdmaa, I. O., Dara, O. M., Lykova, M. A., Borisov, D. G., Ivanova, E. V.
Format: Article
Language:English
Subjects:
Bottom water
Calcite
Chlorite
Clay minerals
Composition
Continental slope
Cores
Deep sea
Deep water
Diagenesis
Earth and Environmental Science
Earth Sciences
Feldspars
Foraminifera
Fracture zones
Gravity
Greigite
Illite
Kaolinite
Marine Geology
Mica
Mineral composition
Mineralogy
Minerals
Oceanography
Opal
Plagioclase
Potassium
Quaternary
Rivers
Sediment composition
Sediment samplers
Sediment samples
Sediments
Siderite
Smectites
Spicules
Suspended load
Valleys
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Summary:The content of sediment-forming minerals in two cores from the eastern (ANS45-37) and western (ANS45-48) parts of the valley of the Vema Fracture Zone is studied using semiquantitative XRD analysis of bulk powder sediment samples. The mineral composition of deep-sea sediments from the Amazone Cone is also analyzed for comparison. It appeared that the average composition of the terrigenous component of both cores (according to prevailing quartz, secondary mica, plagioclase and potassium feldspar, as well as smectite, chlorite, kaolinite, illite) is quite similar and approximately corresponds to the composition of sediments from the Amazon Cone. The ratio of four clay minerals suggests supply of terrigenous material to the Amazon and Orinoco due to erosion of the Andes and humid tropical weathering in the lower courses of the rivers with further transport of the suspended load to the ocean. This material was transported to the valley of the Vema Fracture Zone due to interplay between gravitational flows from the South American continental slope and current of Antarctic Bottom Water. In addition, data on biogenic calcite (planktic foraminiferal tests, nannofossils) and opal A (radiolarians, sponge spicules) have been obtained. In the study area, several authigenic (diagenetic) minerals are identified. In particular, siderite and greigite are first found in the sediments from the Vema valley and Amazon Cone, respectively.
ISSN:0001-4370
1531-8508
DOI:10.1134/S0001437023050077