Fluctuations of eolian flux and ocean productivity in the mid-latitude North Pacific during the last 200 kyr

In order to understand fluctuations in terrestrial and marine environments, a sedimentary core H3571 was investigated from the Hess Rise located in th e mid-latitude North Pacific under the north westerly wind system. The delt a(18)O, grain size and grain shape of type 1 quartz suggest that this quart z is of aerosol origin. Good correlation between Al and aerosol quartz in c ontent and mass accumulation rate (MAR) indicates that the alumino silicate minerals in the sediments are mainly transported by wind. MAR of mineral a erosol (MAR(Aerosol)) varies from 156 to 732 mg cm(-2) kyr(-1) during the l ast 200 kyr. The MAR(Aerosol) maxima occur in oxygen isotope stage (OIS) 4 to latest OIS 5, middle OIS 6, moderate maxima occur in early OIS 1-2, late OIS 3 and middle OIS 3. These maxima are ascribed to reduced precipitation during the summer monsoon and to strengthened wind speed during the winter monsoon. The mean organic carbon/total nitrogen atomic ratio is 7.2, sugge sting that the organic matter in the core H3571 is also mainly of marine or igin. The MAR of organic carbon (MAR(Organic)) exhibits two prominent maxim a in OIS 2 and 4 and relatively high values in middle and late OIS 6. Enhan ced primary productivity is most likely to be responsible for the high buri al rate of organic carbon in the sediments. Carbonate and phosphorus inputs with aerosol into sea surface have played a minor role through dissolution in diminishing PCO2 in surface water during glacial times. On the other ha nd, the aerosol silica supply to the ocean may have some potential to affec t the burial of biogenic silica into sediments. The effect of mineral aeros ol on the ocean carbon cycle would be greater in the coastal and hemipelagi c regions of the Western Pacific and Equatorial Atlantic, as compared with that in the Hess Rise regime. (C) 2000 Elsevier Science Ltd. All rights res erved.