A 36,000 RECORD OF ASIAN DUST DEPOSITION IN HAWAII: PALEOCLIMATIC IMPLICATIONS

East Asian desert dust accounts for the significant inorganic constituent of late Cenozoic sediments in Hawaiian soils. Dust modelling, satellite- and ground-based observations and stable isotope data have contributed to understanding of the dust teleconnection and its mechanisms. The current understanding of the dust processes suggests three potential climate conditions to control Asian dust deposition on glacial-interglacial timescales: 1) aridity in dust source areas, 2) wind intensity in dust transporting winds, and 3) precipitation in deposition areas. However, the lack of paleoaeolian data in Hawaii limits evaluating relative effects of these three dust-controlling factors.

In this study, we present a fine-resolution paleorecord (Present-36 kyr BP) of Asian dust deposition from a Sphagnum bog in a Hawaiian cinder cone. We reconstruct quartz accumulation data by powder X-ray diffraction analyses. Our results show that higher quartz deposition during the Last Glacial Maximum than the Holocene. We find that the quartz data has significant temporal correlations with glacier-interglacial alternations, but no correlation with Hawaiian paleoprecipitation. The dust flux trend in Hawaii shows more similar patterns as those from marine cores at high and mid latitudes rather than equatorial zones. We interpret the temporal pattern of Asian dust flux in Hawaii is more influenced by either the aridity of dust source area or the intensity of dust transporting wind rather than wet deposition processes by Hawaiian rainfall.