Variations in Fe3O4 and CaCO3 Contents in Deep-Sea Cores from the Western Equatorial Pacific.

Abstract

An inverse correlation between the CaCO3 and magnetic mineral contents was obtained from deepsea sediment cores taken from the western equatorial Pacific, in which the predominant magnetic mineral is of bacterial origin. It is shown that the fluctuations of the relative concentration of magnetite over a period of time are caused solely by variations in CaCO3 dissolution in the relatively deep sea bottom. This conclusion seems to explain the observed result that fluctuations in the intensity of saturation isothermal remanence are concordant in two adjacent cores with different sedimentation rates.

Quaternary geomagnetic field intensity: Constant periodicity or variable period?

“…The content of magnetic mineral represented by SIRM has been shown to exhibit almost identical fluctuations even if two cores with largely different sedimentation rates are compared. It has been shown that the fluctuations are caused solely by variations in the CaCO3 dissolution[Sato et al, 1993]. On the basis of the SIRM correlation, the variations of the NRM / SIRM, which are thought to be the first approximation of the paleomagnetic field intensity of the two cores, were compared and a clear correlation was found[Sato and Kobayashi, 1989].…”