Magnetic Susceptibility Measurements

Magnetic Susceptibility (MS) is a simple and rapid tool for reconstructing the paleo-enviromnental records of deep sea sediments (e.g. Robinson 1982; Bloemendal 1983; Oldfield and Robinson 1985). Variations in whole-core volume MS are controlled by the concentration, mineralogy and grain size (domain configuration) of magnetic minerals in the sediment (usually present only in trace quantities in most pelagic sediments, i.e. $<$1 x 10$^{-7}$); by the concentration and type of pararnagnetic (Fe$^{2+}$, Fe$^{3+}$, and Mn$^{2+}$ bearing) clay, or labile minerals in the sediment when magnetic mineral concentration is very low. The potential stratigraphic value of logging MS variations in deep-sea cores has already been noted in quite old studies, e.g. Radhak1968 and Amin1972, and in recent years it has become clear that lithologically-modulated variations in the amount of magnetic material in deep-sea sediments, are often associated with changes in the source of magnetic material input linked to changes in the provenance and/or delivery mechanism of terrigenous detritus. Thus, MS measurements are considered as effective tool for monitoring variations in the supply of terrigenous sediment to the oceans. Whole-core measurements of volume magnetic susceptibility (K), of the cores retrieved during the BIGSETS 98 Cruise, were made at two centimeters intervals by using a Bartington MS2 meter connected to a pass through loop-type sensor of 100 mm diameter. The noise of this sensor is approximately 1x10$^{-6}$ dimensionless S.I. units.

Figure 14: Magnetic susceptibility data.