Rock-magnetic and paleomagnetic studies of marine sediments from the central and western North Pacific: Stratigraphic and paleoceanographic implications

Seong-Jae Doh, University of Rhode Island

Abstract

The ability of rock-magnetic properties to serve as a proxy sedimentological, stratigraphic, and paleoceanographic indicator for deep-sea sediments was tested by detailed rock-magnetic measurements of pelagic sediment cores from the central and western North Pacific.^ Results from the eleven piston cores from the three areas in the western North Pacific show that detailed variations in the rock-magnetic parameters can be readily correlated between cores within each area. Major trends in the magnetic grain-size variation recorded in two calcareous sediment cores (DSDP Holes 577 and 577A) are consistent with those of a core from the central North Pacific (LL44-GPC3). This relationship indicates that rock-magnetic techniques provide a rapid and non-destructive tool for regional and possible basin-wide correlation of pelagic sediment cores.^ The observed regional magnetic grain-size variations of the study cores are in good agreement with the eolian grain-size data obtained from analyses of the total eolian component of the sediment, indicating that grain-size-dependent rock-magnetic parameters can provide information about total eolian grain-size variation. Major fluctuations in concentration-dependent rock-magnetic parameters plotted as accumulation rates for core LL44-GPC3 correspond to intervals of paleoenvironmental change that have been detected previously by other paleoceanographic methods. Thus, rock-magnetic methods constitute a valuable new tool for paleoceanographic studies, because of their speed, simplicity, and non-destructiveness.^ Rock-magnetic parameters show a distinctive pattern of high concentration of relatively coarse magnetic grains at the Cretaceous/Tertiary (K/T) boundary in cores from both the central and western North Pacific, suggesting that these techniques may provide a valuable tool for rapidly identifying the K/T boundary.^ Finally, detailed paleomagnetic records of two calcareous sediment cores provide excellent magnetostratigraphies that are characterized by a complete geomagnetic polarity sequence for the interval 0-5 Ma and an almost complete polarity sequence for the interval 50-70 Ma. ^

Subject Area

Geophysics|Physical Oceanography

Recommended Citation

Seong-Jae Doh, "Rock-magnetic and paleomagnetic studies of marine sediments from the central and western North Pacific: Stratigraphic and paleoceanographic implications" (1988). Dissertations and Master's Theses (Campus Access). Paper AAI8811553.
http://digitalcommons.uri.edu/dissertations/AAI8811553

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