bcspace wrote:I have not heard of a process that ultimately freezes currents and eddies of water in stone.
BC,
Examples of how these shoreline and wavelike sediment deposition patterns are preserved can be seen at
this website that describes Glacial Lake Missoula and the downstream consequences of periodic catastrophic floods, including the channeled scablands of Southeastern Washington State.
From the images and video here you will see how the features are formed. Please notice the periodicity or "wavelength" (some of 100 feet or more) of the ripple features in the video and in the Google Earth aerial images. They are much larger than the small ripples one sees at a lakeshore for example. This is because of the shear energy involved when several hundred cubic miles of water are released from a failed dam that is hundreds of feet high.
Notice the droprocks, erratics, varves, rhythmites, and strandline features that these periodic floods left behind. We incorporated a droprock from one of these floods that was the size of a small car into the landscaping of our home there. Our house was located several hundred feet above the valley floor.
These features can be "frozen in time" when the water retreats and the ripple patterns are buried, or even as they consolidate at or near the surface (as seen with the consolidated rock flour in the video at this website).
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ETA: Just saw that, while I was writing this post, you mentioned Lake Missoula, so sorry if all this is redundant. The website is still worth a look, however, if for nothing else but some nice photography.