No significant HIRM change is observed at the transition between oxidising and reducing conditions in the sediment (Fig. 9A). This implies that HIRM is not affected by redox conditions and further confirms that the “hard” magnetic mineral content is the best tracer of detrital input (Peck et al., 1994). On the other hand, the S-ratio seems to be related to the redox conditions in the sediment (see Section 7.2). The ARM has also to be considered with caution as it is mainly influenced by the ferrimagnetic contribution, which is itself influenced by post depositional processes. This is seen in Fig. 9 where ARM variations are partly influenced by S-ratio variations.
We established a mastercurve “Baikal 200” of relative paleointensity, which represents a new synthetic paleomagnetic archive for Central Eurasia. The synthetic record is composed of mean values of the six records with respect to a sliding time window of 2 ka. This compilation has been restricted to the last 200 ka in order to maintain a representative population of points (between 2 and 68). However, we present this synthetic record together with individual records and the reference paleointensity curve (Fig. 11) for the following reasons:
– Each relative paleointensity record has a different resolution (e.g., sedimentation rates in CON 01-605-3 are five times higher than in VER 98-1-14). During stack procedure, smoothing of the data had the effect of lowering the resolution of the paleomagnetic information.
– This stack does not provide more information on timing of the geodynamo changes since the records are tuned to ODP Site 984.