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Unanswered Questions

PostPosted: May 7, 2008 12:45 pm
by TheRookie
Hello all!

I'm new to the board and I tried to look for some of my questions, but no luck. I'm one confused caver - overwhelmed with info! Please help :)

First - besides scallops what are other indicators of water flow direction in a cave?

Secondly - How are tubular and deep narrow winding canyons passages formed? And when they are formed will the water table be up or down?

Thanks for any help & info!!

Re: Unanswered Questions

PostPosted: May 7, 2008 1:27 pm
by Phil Winkler
Jess,

Flowstone and travertine dams often indicate the direction of earlier water flows.

You might want to pick up a book about cave formation to read more: Jenning's "Karst" comes to mind, but there is a new one by Art Palmer that is getting great reviews, too. Check out the NSS Bookstore on www.caves.org

Re: Unanswered Questions

PostPosted: May 7, 2008 3:55 pm
by fireman1904
The tubular passages you refer to are formed when the caves were below the water table and the water started disolving the limestone etc. in the area of the joints and cracks. The winding canyon passages are formed above the water table or as it drops. Streams flowing through the cave dissolve and abrade the limestone away and cut down through the stone. There are more technical terms and descriptions but that should give you some idea of what is going on.

Re: Unanswered Questions

PostPosted: May 7, 2008 4:18 pm
by wyandottecaver
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.

Re: Unanswered Questions

PostPosted: May 7, 2008 5:25 pm
by Marlatt
I'd second the recommendation for Palmer's new Cave Geology. Great book. You might also want to peruse some of the papers on the Speleogenesis website (http://www.speleogenesis.info/old_journal_index.php) - as has been noted here, passage morphology can be the result of differing causative mechanisms. In the case of canyons, they can form in response to vadose downcutting, joint-controlled phreatic enlargement, as joint-dominated flood mazes, or perhaps due to confined artesian conditions.

The most reliable method I've found to determine the direction of water flow is to drop a float into the water and see which way it goes! :tonguecheek:

Stuart

Re: Unanswered Questions

PostPosted: May 8, 2008 1:50 pm
by rpaylor
If there are sand and cobble sediment banks in the cave, you can get an idea of flow direction. Small stones and cobbles become "imbricated", or stacked on each other like roof shingles. The direction of the stacking tells you which way the water flowed:

water flow ------------>
cobbles: ///////////