The MS is generally ~20 x 10–5 SI in the upper 11.5 m and lowermost 1.5 m of the sequence (Fig. F3). In the interval between 111.5 and 118 mbsf, the values are slightly lower, in the range of 15 x 10–5 SI.
The NRM intensity is <1 x 10–2 A/m except for two spikes at 100.9 and 102.3 mbsf. At the same depths, high values of MS and ARM intensity are observed (Fig. F3). The features of the NRM intensity are mirrored in the ARM intensity and ARM/k ratio, with higher values in the upper 3 m of the core and in the shorter interval at 108–109.5 mbsf. The magnetic hardness (ARM30 MT/ARM0 MT) is relatively constant from the bottom of the cored section up to 103 mbsf, at which point it increases slightly, similar to the other parameters. The Day plot (Day et al., 1977) (Fig. F5) shows that the grain size of the magnetic carriers is variable, but falls within the pseudo-single-domain field for magnetite.
The NRM intensity is 7.4 x 10–3 A/m on average, with highest values in the intervals between 0 and 40 and between 84 and 110 rmbsf (Fig. F4). The uppermost interval is characterized by a distinct intensity peak with values as high as 0.024 A/m.
The typical MS value is ~20 x 10–5 SI, but many >200 x 10–5 SI are present, especially in the depth intervals between 80 and 94 and between 101 and 110 rmbsf. In these intervals, the spikes in MS often correspond to spikes in the NRM and ARM intensity. Although the MS signal is rather noisy, a trend is clearly discernable. After a slight downcore decrease at the uppermost part in the most recent sediment, the MS shows a trend characterized by two peaks at ~30 and 68 rmbsf. A correspondence exists between the MS and NRM intensity in those intervals in which the latter is high, but the MS in the rest of the core is characterized by significant variability. The ARM intensity is similar to the NRM intensity except in the interval between 69.4 and 86.5 rmbsf, where the ARM intensity tends to increase.
The parameters ARM/k and magnetic hardness (ARM30 mT/ARM0 mT) are commonly used in environmental magnetism. They are sensitive to the magnetic grain size and coercive force. In this case, they mirror the ARM intensity, with the highest values in the intervals at 0–40 and 69.4–110 rmbsf. As in Hole 1202A, the hysteresis parameters suggest that the magnetic carriers fall within the range of pseudo-single-domain magnetite grains (Fig. F5).
The thermoremanence investigations indicate that the dependence of the MS with temperature is similar throughout the sequence (Fig. F6). The heating curves show a strong increase in MS after 280º–300ºC because of chemical alterations during heating. A prominent peak appears at ~490ºC and is followed by a sharp drop in the MS, indicating a Curie temperature (Tc) of ~540ºC. This is 40ºC lower than the Curie temperature of pure magnetite and is indicative of a low-titanium magnetite generated during the heating process.