Abstract

Atmospheric dust fallout and ice-rafted glacial detritus are significant factors for the Arctic Ocean sediment budget. Atmospheric dust amounting to .09 mm/1,000 yrs is being delivered to the Canada Basin, Chukchi Plain and Alpha Cordillera areas today. This is 10 percent of the sedimentation rate for some parts of the Arctic Ocean during the past 2 to 3 m.y. Clay mineralogy of the modern atmospheric dust and of the Arctic Ocean sediment is approximately 40 percent illite with almost equal amounts of chlorite and kaolinite.

Ice-rafted detritus is widespread on the Arctic Ocean floor today. In addition, erratics greater than 8 mm and less than 40 mm have been found in 44 of almost 100 cores studied to date. These erratics are carbonates and sandstones in large part; metamorphics and cherts are less abundant. No pattern of lithologic and vertical distribution correlation of erratics among the cores is present. The oldest erratic occurs in sediment approximately 3.5 m.y. old. In excess of 30 percent by weight of some Arctic sediment consists of greater than 62 μ material. This is largely ice-rafted material. Together with the atmospheric dust fallout, this is a significant part of the average 2 to 3 mm/1,000 yrs sedimentation rate determined from magnetic stratigraphy.

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