The magnetic properties of some deep sea sediments
The magnetic properties of some deep sea sediments
The Detrital Remanent Magnetization (DRM) and anisotropy of magnetic susceptibility of unconsolidated Recent sediments frog seven Mediterranean Sea cores have been measured and the results shown to afford important sedimentological applications. Records of short period geomagnetic secular variation revealed by the DRM of these sediments enable bettoen-core time correlations to be achieved. They provide also an estimate of both relative and absolute rates of sediment accumulation. For the abyssall plain of the Tyrrhenian Sea, sedimentation rates are determined in the range 65-130 cm./1000 yr. Sediment transport directions are inferred from the lineation of axes of maximum susceptibility.These sediments further present an opportunity to investigate the process of DRM, acquisition. Inclination errors of variable magnitude are significant in such current-deposited deep sea material containing a predominantly terrigenous component; the importance of grain fabric and remanence carrier inclusions to this variability remain to be assessed. Particles responsible for the remanent magnetization are shown here to contribute to the magnetic susceptibility anisotropy. A series of laboratory redepositions indicate that post-depositional rotation of remanence carriers occurs during the acquisition of a stable grain fabric associated with the effects of sediment compaction. An investigation of the magnetic mineralogy of four of the cores, using X-ray diffraction and thermomagnetic techniques, confirms the presence of non-stoichiometric titanomagnetites. DRM intensities are dependent on the titanomagnetite content of the sediment, as determined by volume susceptibility measurements. Additional remanent magnetization measurements on Oligocene/Miocene sediments from Deep Sea Drilling Project site 238 are reported. This represents part of a continuing study of the' northward motion of the Indian Plate through the Tertiary. The results presented here suggest that there has been no major (< 5°) latitudinal change since this time.
University of Southampton
1975
Blow, Richard Andrew
(1975)
The magnetic properties of some deep sea sediments.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The Detrital Remanent Magnetization (DRM) and anisotropy of magnetic susceptibility of unconsolidated Recent sediments frog seven Mediterranean Sea cores have been measured and the results shown to afford important sedimentological applications. Records of short period geomagnetic secular variation revealed by the DRM of these sediments enable bettoen-core time correlations to be achieved. They provide also an estimate of both relative and absolute rates of sediment accumulation. For the abyssall plain of the Tyrrhenian Sea, sedimentation rates are determined in the range 65-130 cm./1000 yr. Sediment transport directions are inferred from the lineation of axes of maximum susceptibility.These sediments further present an opportunity to investigate the process of DRM, acquisition. Inclination errors of variable magnitude are significant in such current-deposited deep sea material containing a predominantly terrigenous component; the importance of grain fabric and remanence carrier inclusions to this variability remain to be assessed. Particles responsible for the remanent magnetization are shown here to contribute to the magnetic susceptibility anisotropy. A series of laboratory redepositions indicate that post-depositional rotation of remanence carriers occurs during the acquisition of a stable grain fabric associated with the effects of sediment compaction. An investigation of the magnetic mineralogy of four of the cores, using X-ray diffraction and thermomagnetic techniques, confirms the presence of non-stoichiometric titanomagnetites. DRM intensities are dependent on the titanomagnetite content of the sediment, as determined by volume susceptibility measurements. Additional remanent magnetization measurements on Oligocene/Miocene sediments from Deep Sea Drilling Project site 238 are reported. This represents part of a continuing study of the' northward motion of the Indian Plate through the Tertiary. The results presented here suggest that there has been no major (< 5°) latitudinal change since this time.
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Published date: 1975
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Local EPrints ID: 462671
URI: http://eprints.soton.ac.uk/id/eprint/462671
PURE UUID: 8aa11315-8a78-4828-be78-15441d1b08c3
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Date deposited: 04 Jul 2022 19:40
Last modified: 04 Jul 2022 19:40
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Author:
Richard Andrew Blow
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