Late Pleistocene sediment and oxygen isotope record of the Northwest Pacific

Dust fluxes range from 43 to 718 mg(cm**2 kyr)**-1 and are greater by a factor of about 4 during glacial times. Cross-spectral analysis of the eolian flux and oxygen isotope records shows an inphase and coherent relationship at each of the major orbital periodicities of 100, 41, and 19 kyr. Eolian grain sizes, generally used as a proxy record of wind intensity, range from 8.4 phi (2.9 µm) to 6.2 phi (13.6 µm).

A change in grain size variability occurs near about 300 ka such that the older portion is characterized by lower-frequency and higher-amplitude fluctuations than the younger portion. Power spectra for the eolian grain size record show dominant peaks at 100 and 50 kyr and a broad 25-35 kyr peak but coherency to the oxygen isotope curve at only the 100 and 33 kyr periodicities. The phase relationship for eccentricity between the eolian grain size and delta18O records suggests that at the 100 kyr frequency the smallest grain sizes are associated with glacial conditions.