Applying magnetostratigraphy to lacustrine sediments to obtain a non-hard-water-effect affected pattern of late Holocene monsoon dynamics on the Tibetan Plateau

The Tibetan Plateau is commonly believed to react very inhomogeneous to monsoon variations. This is hitherto attributed to complex responses to environmental and atmospheric variations due to extreme differences in the mountain landscapes where minor differences in elevation can cause strong variation in microenvironments (Wischnewski et al. 2011). Another important role play differences in the source of the monsoon which potentially affect different regions of the Tibetan Plateau. However, it was possible to show a similar pattern of Indian Ocean Summer Monsoon strength, i.e., hydrological variations, in Nam Co (Co = lake) located on the central Tibetan Plateau and Hongyuan peat bog (Hong et al. 2003) situated on the north-eastern margin of the Plateau (Kasper et al. submitted). Peat dating at Hongyuan minimizes reservoir effect uncertainties since it is generally accepted that the dating of peat samples is hardly affected (Long et al., 2010). The chronology of Nam Co was supported by the comparison of paleosecular variations calculated from these sediments to geomagnetic field models (Kasper et al. submitted). This was necessary since almost all radiocarbon ages obtained from lacustrine sediments on the Tibetan Plateau are affected by a reservoir effect. In this study we present late Holocene paleosecular variations obtained from lacustrine sediments from Nam Co, Tangra Yumco, Donggi Cona, Peiku Co and Npen Co - all located on the Tibetan Plateau and considerably affected by a reservoir effect. We show the applicability of paleomagnetic investigations on sediments from these lakes and how these analyses can help to emerge the contemporaneousness of certain hydrological variations during this time. This is done by comparing and tuning for example inclination or declination to geomagnetic field models or interarchive comparison of the lakes mentioned above. Applying this approach for example to Nam Co and Tangra Yumco, a very similar progression of hydrological variations can be observed. Together with the similarities observed in the Hongyuan peat bog this suggests, that the main variations in monsoon strength might not be as inhomogeneous as previously assumed.