by wyandottecaver » May 7, 2008 4:18 pm
actually, things can get complicated.
scallops *can* indicate flow, but they can be old artifacts and hydrology might have changed, some eddies can create reverse scallops etc. If present, look for large boulders and see which direction the eddie pockets behind them are. the pockets will generally be downstream.
deep, narrow, winding canyons can be a result of 1) fissures or cracks enlarged by water erosion, or 2) a rapid drop in the water table (geologic time) that promotes rapid downcutting rather than widening, or 3) the result of seams previously filled by a highly soluble substance like gypsum that were later dissolved 4) all the above :)
tubular passages may be formed below the water table, or they can be the result of "polishing" when highly aggressive flood waters (high volume, high pressure, low level of mineral saturation) rise and "clean up" those offending projections and irregularities.
Art Palmer's book "Cave Geology" is a great resource.
I'm not scared of the dark, it's the things IN the dark that make me nervous. :)