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|Title: ||Incorporation of particulates into accreted ice above subglacial Vostok lake, Antarctica|
|Authors: ||Siegert, M. J.|
Priscu, J. C.
|Issue Date: ||2005|
|Citation: ||Siegert, M. J., Royston-Bishop, G., Priscu, J. C., Tranter, M.. (2005-01-01) Incorporation of particulates into accreted ice above subglacial Vostok lake, Antarctica, Annals Of Glaciology 40(1) 145-150|
|Abstract: ||The nature of microscopic particulates in meteoric and accreted ice from the Vostok (Antarctica) ice core is assessed in conjunction with existing ice-core data to investigate the mechanism by which particulates are incorporated into refrozen lake water. Melted ice samples from a range of icecore depths were filtered through 0.2 μm polycarbonate membranes, and secondary electron images were collected at ×500 magnification using a scanning electron microscope. Image analysis software was used to characterize the size and shape of particulates. Similar distributions of major-axis lengths, surface areas and shape factors (aspect ratio and compactness) for particulates in all accreted ice samples suggest that a single process may be responsible for incorporating the vast majority of particulates for all depths. Calculation of Stokes settling velocities for particulates of various sizes implies that 98% of particulates observed could 'float' to the ice water interface with upward water velocities of 0.0003 m s-1 where they could be incorporated by growing ice crystals, or by rising frazil ice crystals. The presence of particulates that are expected to sink in the water column (2%) and the uneven distribution of particulates in the ice core further implies that periodic perturbations to the lake's circulation, involving increased velocities, may have occurred in the past.|
|Appears in Collections:||Global Change Research Institute publications|
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