Abstract
Sediments around Great Meteor Seamount (about 30°N 28°W) are pelagic calcareous oozes with an unusually high proportion of silt. The upper “A-interval” comprising Holocene and Late Pleistocene (i.e. the last 130,000 years) is yellowish-brown and exhibits strong bioturbation. The lower “B-interval” (Late to Middle Pleistocene) is white and extremely carbonate-rich with a silt maximum formed mainly by coccoliths. These coccoliths are the main part of a considerable proportion of allochthonous carbonate material which was reworked from the upper slope and summit of the seamount. On the eastern flank the sediments of the B-interval show the strongest input of displaced material, the highest sedimentation rates, distinct lamination, and lack of bioturbation. We explain the asymmetric distribution of the sediments east and west of Great Meteor Seamount by different bottom current velocities. The velocity of the northeastward-flowing Antarctic Bottom Water (AABW) is enhanced at the western flank of the obstacle and decreased east of it, mainly as a consequence of the Coriolis force. Because the ocean circulation and AABW intensity were stronger during the period earlier than 130,000 years ago, asymmetric sedimentation was more pronounced at that time.
Published Version
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