Rock magnetism of late Neogene and Pleistocene deep-sea sediments; relationship to sediment source, diagenetic processes, and sediment lithology

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doi: 10.1029/91JB03068
Author(s): Bloemendal, J.; King, J. W.; Hall, F. R.; Doh, S. J.
Author Affiliation(s): Primary:
Univ. Liverpool, Dep. Geogr., Liverpool, United Kingdom
Univ. R.I., United States
Univ. Del., United States
Korea Univ., South Korea
Volume Title: Journal of Geophysical Research
Source: Journal of Geophysical Research, 97(B4), p.4361-4375. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148-0227
Note: In English. 78 refs.; illus. incl. 1 table, sketch maps
Summary: We use bivariate scatter plots to illustrate variations in selected rock magnetic properties (low-field susceptibility, anhysteretic and isothermal remanence) of late Neogene and Pleistocene deep-sea sediments from 16 sites in the Arctic Ocean, North Atlantic, equatorial Atlantic and North Pacific Ocean, and the Arabian Sea. Our intention is to examine the ability of the rock magnetic properties to differentiate the sediments according to factors such as lithology, geographical area, and the dominant mode of terrigenous sedimentation, which at these sites is via ice-rafting, via bottom currents, or via eolian processes. Overall, correlations between sediment magnetic properties and gross lithology is poor, and factors such as the source and transport path of terrigenous sediment (and detrital magnetic minerals), together with the action of reductive diagenetic processes, are the major controls on the magnetic properties. On the bivariate scatter plots, sites with major ice-rafted contributions tend to have high sedimentary ferrimagnetic mineral concentrations, relatively coarse ferrimagnetic grain-sizes, and scattered sample point distributions; in contrast, sites where we infer significant bottom-current supply of terrigenous material have tightly grouped sample point distributions. Carbonate sediments in which the terrigenous component is supplied by eolian processes tend to have a broad range of magnetic mineral concentration, caused by glacial-interglacial fluctuations in carbonate accumulation and eolian activity. Sediments containing significant volcanogenic material have high concentrations of relatively coarse-grained ferrimagnetic material. Reductive diagenesis is a significant determinant of sediment magnetic properties in high-productivity areas and has the effect of preferentially removing the fine-grained ferrimagnetic fraction, causing a coarsening of the ferrimagnetic grain-size distribution and a rise in the antiferromagnetic:ferrimagnetic ratio. Copyright 1992 by the American Geophysical Union.
Year of Publication: 1992
Key Words: 07 Marine Geology and Oceanography; 12 Stratigraphy, Historical Geology and Paleoecology; Anhysteretic remanent magnetization; Arabian Sea; Arctic Ocean; Atlantic Ocean; Cenozoic; Deep-sea environment; Diagenesis; Effects; Equatorial Atlantic; Glacial environment; Glaciomarine environment; Indian Ocean; Isothermal remanent magnetization; Magnetic properties; Magnetic susceptibility; Magnetization; Marine environment; Marine sediments; Neogene; North Atlantic; North Pacific; Pacific Ocean; Paleomagnetism; Pleistocene; Pliocene; Provenance; Quaternary; Remanent magnetization; Sedimentation; Sediments; Statistical analysis; Stratigraphy; Terrigenous materials; Tertiary; Wind transport
Record ID: 1992021407
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.

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