2012 年 27 巻 3 号 p. 284-291
The eolian dust in the sediments of North Pacific and marginal seas of the northwestern Pacific has potential to record past climate changes. For example, the variability of eolian dust flux estimated from North Pacific sediments have been interpreted as recording past aridity changes of the eolian source region of the East Asia. However, recent observations revealed large effects of the wind-systems on the amount of dust transported to the North Pacific and marginal seas. Therefore, it is important to consider both effects of the wind-systems and aridity changes when we interpret eolian dust parameters. Recently, we estimated provenance of eolian dust in Japan Sea sediments and reconstructed its variations during the last glacial period based on a newly developed provenance-tracing method, a combination of electron spin resonance intensity and the crystallinity of quartz. The result revealed millennial-scale provenance changes in accordance with so-called Dansgaard-Oeschger (D-O) events, with dominance of quartz from the Mongolian Gobi during cold intervals of D-O events, whereas dominance of quartz from the Taklimakan Desert during warm intervals of D-O events. These provenance variations seem to mainly represent latitudinal displacement of the subtropical jet path in harmony with D-O events.