石英結晶の物理的性質に基づくダスト供給源推定と過去の偏西風変動の復元

抄録

Aeolian dust in the sediments of East Asian marginal seas potentially records past variations in the westerly jet. However, extracting information about aeolian dust from these marine sediments is difficult because the sediments also contain detrital materials of the riverine input. Here we present a newly developed provenance-tracing method by using a combination of electron spin resonance (ESR) signal intensity of the E₁′ center in quartz and crystallinity index (CI) of quartz, which we applied to Japan Sea sediment to identify aeolian dust within the sediment and estimate its provenance. We then reveal temporal changes in the provenance of aeolian quartz in Japan Sea sediments, which exhibit variations in harmony with Dansgaard–Oeschger (D–O) events during the last glacial period. The dominance of quartz with a Mongolian Gobi (Taklimakan) provenance during D–O cold (warm) periods suggests earlier (latter) seasonally northward progression of the westerly jet. The changes of the westerly jet path apparently critically affect the teleconnection between the climates of Asia and North Atlantic on a millennial timescale.