P. W. Barnes
W. S. Weber
E. Reimnitz
1993
<div class="abstract-content"><div class="abstract" data-abstract-type="normal"><p>Ice observations and sediment samples were collected in the Beaufort Gyre in 1988. Fine sediment occurred in very small patches of turbid ice, as thin spotty surface layers, in mud pellets or in old snowdrifts. The latter were widespread south of 74°N, containing an estimated 22 tonnes of silt and clay km<span class="sup">−2</span>. Average particle concentration in sea ice (40mg l<span class="sup">−1</span>) was much higher than in sea water (0.8 mg l<span class="sup">−1</span>) or in new snow, but the sediment load was significantly smaller and of finer texture compared to that observed in a shelfal source area after a major entrainment event. About 30% of the sediment consisted of small pellets. Mud in pellets has similar texture, clay minerals and organic/inorganic carbon content as dispersed mud. Particle sizes <16μm dominate, sand is less than 1%, compared to as much as 8% in four samples obtained in 1971 and 1972. Organic carbon content is about 2%, illite dominates clay minerals (~50%), and diatoms suggest a shelf sediment source. From the prevalence of wind-reworked surficial deposits, the spotty occurrence of only small patches of turbid ice in old clean ice, and the virtual lack of sand-size material, we assume the sediment had drifted at least 2 years since entrainment and was distant from its source. Assuming one-third of the load is released each year, the estimated deposition rate would equal the measured Holocene rate (~2cm 1000year<span class="sup">−1</span>). Therefore, modern sea-ice rafting represents a substantial fraction of the total Arctic Ocean sediment budget.</p></div></div>
application/pdf
10.3189/S0022143000015823
en
Cambridge University Press
Particulate matter in pack ice of the Beaufort Gyre
article