Two unusual Arctic Ocean sedimentary processes involve deposition of clay-size particles and deposition of glacial-marine erratics. The clay suite identified by X-ray diffraction in 50 cores from the Chukchi Rise and Alpha Cordillera consists mainly of illite with almost equal combined amounts of chlorite and kaolinite. Similar clays are present in atmospheric dust in permanent snow fields of northern Greenland. In addition, dust separated from snow samples of the Arctic ice pack contains these same clay minerals. This dust finds its way into leads during summer melting where it contributes an estimated 0.4 mm of sediment per 1,000 years. This is almost ½ of the total sedimentation rate for parts of the Arctic and up to 90% of the 2-µ size fraction sediment.

Pebbles have been found in 36 cores. Few striations have been noted but ice rafting is a believable mechanism to explain pebbles in the central Arctic Ocean. Twenty-three cores contain erratics at more than 1 level and as many as 7 are present in 300-cm cores; 38% are sandstone, 29% carbonate, 15% metamorphic, and 18% chert or unidentified clasts.

Distribution of the erratics shows no pattern that can be explained by known currents or events in time. Erratics are present in brown cores but no erratic has been found in gray cores. Turbidity structures characterized some of the gray cores. Probably, erratics were deposited randomly over most of the Arctic basin from melting glacial ice, but they appear to be less common in deeper parts of the ocean (Canada plain) where high sedimentation rates associated with turbidity flows mask their presence.

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