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<p>It has long been considered that dust flux reflects dryness in the source area, whereas dust grain size reflects vigor of the transport wind, although recent studies stress the importance of supply of raw materials (siliciclastic sediments) to the dust source (emission) area either by tectonic or by glacial activities in the surrounding mountainous areas. Dry areas in inland East Asia are the major sources of the dust (called Asian dust) to the northern hemisphere, and the Gobi Desert and Tarim Basin (including Taklimakan Desert) are top two sources of Asian dust at present. Dust from the Gobi Desert is dominantly carried by mid-latitude migratory cyclones at lower altitude (&lt; 5&#xa0;km) to the east, whereas dust from the Tarim Basin is mostly carried by the westerly jet at higher altitude (&gt; 5&#xa0;km) and was spread all over the northern hemisphere. These two major dust sources can be discriminated against each other by combination of provenance tracers such as electron spin resonance (ESR) signal intensity plus crystallinity index (CI) of quartz and Nd plus Sr isotopes. So, if we could know distribution of the past dust source areas and their provenance signatures in each time slices, it is possible to reconstruct the course and intensity of westerly jet and/or migratory cyclones and their changes with time from spatiotemporal distribution of fluxes and grain sizes of the dust from each source area in the North Pacific. In this review, I summarize the data on fluxes, grain sizes, and provenance of Asian dust preserved in fine-grained sedimentary sequences in proximal (desert sand and loess accumulated areas in East Asia), intermediate (East Asian marginal seas), and distal (North Pacific) areas and reconstruct their temporal changes since the late Eocene in tectonic (million years) and orbital (10 to 100 kilo-years) time scales. Then, I examine the interrelationships of those changes between proximal, intermediate, and distal areas to obtain unified view on evolution of source-to-sink processes of Asian dust and explore their control factors. I also examine the potential importance of Asian dust in global biogeochemical cycles and consequent climatic changes. </p>

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Asian dust to the North Pacific since the late Eocene: from source to sink

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  • 发表日期：

    2026年7月14日

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  • Ryuji Tada

摘要

It has long been considered that dust flux reflects dryness in the source area, whereas dust grain size reflects vigor of the transport wind, although recent studies stress the importance of supply of raw materials (siliciclastic sediments) to the dust source (emission) area either by tectonic or by glacial activities in the surrounding mountainous areas. Dry areas in inland East Asia are the major sources of the dust (called Asian dust) to the northern hemisphere, and the Gobi Desert and Tarim Basin (including Taklimakan Desert) are top two sources of Asian dust at present. Dust from the Gobi Desert is dominantly carried by mid-latitude migratory cyclones at lower altitude (< 5 km) to the east, whereas dust from the Tarim Basin is mostly carried by the westerly jet at higher altitude (> 5 km) and was spread all over the northern hemisphere. These two major dust sources can be discriminated against each other by combination of provenance tracers such as electron spin resonance (ESR) signal intensity plus crystallinity index (CI) of quartz and Nd plus Sr isotopes. So, if we could know distribution of the past dust source areas and their provenance signatures in each time slices, it is possible to reconstruct the course and intensity of westerly jet and/or migratory cyclones and their changes with time from spatiotemporal distribution of fluxes and grain sizes of the dust from each source area in the North Pacific. In this review, I summarize the data on fluxes, grain sizes, and provenance of Asian dust preserved in fine-grained sedimentary sequences in proximal (desert sand and loess accumulated areas in East Asia), intermediate (East Asian marginal seas), and distal (North Pacific) areas and reconstruct their temporal changes since the late Eocene in tectonic (million years) and orbital (10 to 100 kilo-years) time scales. Then, I examine the interrelationships of those changes between proximal, intermediate, and distal areas to obtain unified view on evolution of source-to-sink processes of Asian dust and explore their control factors. I also examine the potential importance of Asian dust in global biogeochemical cycles and consequent climatic changes.