[Get a load of this latest piece from Byers ... especially the part where he thinks that "ice" and "frozen water" are two different entities ... I kid you not ...]
The timeframes must be short enough to fit biblical chronology. Creationists differ but this one sees the "ice age' starting some 4 centuries or so after the flood, by tree ring count, and lasting a few hundred years and over with a sudden melt.
Now there are issues about glacial covering of earth. i believe one creationist has suggested the "glaciers" were not ice but frozen water. that is they were not created by weight of snow but massive frozen water from rain and snow.
Yet their movement would need explanation and other details. The source of the megameltwater events, a famous topic in geomorphology here, would be explained better if the "ice" was just frozen water mostly. However I'm just suggesting this.
I didn't know the rock this erratic came from but its fine what it is. A rock from volcanic or heating/melting rock with a source in sedimentary works for me. These rocks all from the great results of the flood year.
We just quicken the pace of moving continents and their crashing/splitting and here and there volcanic outporings under or above ground, though covered by water, and so metamorhic (sp) rock.
Then a glacier or moving frozen ice or meltwater picked up a piece and dropped it downstream.