Paleointensity versus age of all the sedimentary sequences of the present study, of the synthetic curve resulting from its compilation from other curves, and of the reference curve from ODP Site 984 (Channell, 1999). For the compilation, data have been averaged using a sliding window of 2 ka (the variance is marked by the grey shadow). Dashed lines show some of the correlations. The grey lines show the location of the low paleointensities related to geomagnetic excursions. Note that the lowest paleointensities in the time span of Blake are at c. 129 ka. (see Fig.11)
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.
Selected intervals of down-core variations of normalised relative paleointensity, ChRM inclination and declination, and the reversal angle. (A) Core CON 01-603-2: numbers in the simplified lithological column indicate marine isotope stages (MIS), after Fig. 3. The paleomagnetic data show a geomagnetic excursion with a short, but full, reversal of the local field vector at the beginning of MIS 6. (B) Core VER 98-1-1: in this case, the excursion represented by a strong deviation of the reversal angle during a period of low intensity occurs in MIS 3 and corresponds to the Laschamp event. (C) Core VER 98-1-1: in this case, the excursion is also represented by a strong deviation of the reversal angle during a period of low intensity. Again this occurs in MIS 3 and corresponds to the Laschamp event.