02038nas a2200181   4500008004100000022001400041245011000055210006900165260001200234300000900246490001400255520146300269100001801732700001501750700002201765700002101787856004801808       2015                        eng d  a1365-207900aSediment transport dynamics on an ice-covered lake: The “floating” boulders of Lake Hoare, Antarctica0 aSediment transport dynamics on an icecovered lake The floating b  c04/2015  a1-120 vfirstview3 a<p>Between 1995 and 2011 a global positioning system survey of 13 boulders and three ablation stakes (long stakes frozen in the ice) on the frozen surface of Lake Hoare was undertaken. Data interpretation illustrates complexities of post-depositional transport dynamics of boulders. Earlier studies on comparable datasets have suggested linear &lsquo;conveyor&rsquo; type transport mechanisms for lake surface boulders. Yet explanations for non-linear boulder displacements or &lsquo;walks&rsquo; and the mechanisms responsible for movements are inadequate. Two modes of boulder specific movement were observed. First, localized changes in the ice surface promote individual boulder movement (rolling). Second, ice rafting, which indicates the displacement of &lsquo;plates&rsquo; of lake ice on which the boulder is located. Ablation stakes used as fixed survey control points support the hypothesis that ice cover moves as discrete plates rather than as a single homogenous mass. Factors that create the conditions to generate either of the two modes of movement may be related to location specific energy budgets. A relationship between average orientations and prevailing wind direction was also observed. The investigation describes the local-scale behaviour of surveyed boulders, and offers methodologies and interpretive frameworks for additional studies of modern and ancient sediment transportation dynamics in Antarctic lacustrine environments.</p>1 aAllen, P., P.1 aHewitt, R.1 aObryk, Maciek, K.1 aDoran, Peter, T.  uhttp://dx.doi.org/10.1017/S0954102014000558