Cave sediments

[FW]

That "Alabama red clay", is also called "Georgia red clay". And goes at least as far west as Arkansas.

[RN]

Ah. I've seen clays and silts of many colours, but tend to see more gray clays here in central Florida/north central Florida. I have yet to make it up to your beautiful caves in even-more-north Florida. Jason, are more red clays found in the even-more-north Florida caves due to their closer proximity to the channel that was filled by those siliclastic sediments?

Was this during LCF's SM dive?

No, this was actually in a passage that is easily done in backmount. It's just unforgiving, even with good technique. It's small enough that any movement through it causes the bottom to stir up. It's a short passage with no off shoots until you get back into larger passage. You can usually see going through it once, but we always turn around for the full effect. It's a perfect place to expose the uninitiated to silt outs and I take all my cave students through there.

[SuPrBuGmAn]

No, this was actually in a passage that is easily done in backmount. It's just unforgiving, even with good technique. It's small enough that any movement through it causes the bottom to stir up. It's a short passage with no off shoots until you get back into larger passage. You can usually see going through it once, but we always turn around for the full effect. It's a perfect place to expose the uninitiated to silt outs and I take all my cave students through there.

Lulz, I know where that is it gets pretty after a bit..

[Xenia]

Is this the very first jump at Twin? (before the drop off). This is a beautiful one..

[Webmaster]

Now the really interesting question is why are there are laminated clay layers indicative of low flow in high flow caves like Cow or Ginnie (or others)..... (we're working on it.... and if we figure anything out - I'll be sure to let you know).

So you don't think something within the range of observed flow is enough to account for the deposits? Is there any indication of seasonality in the laminations?

Higher rainfall locally, longer periods of low flow conditions?

[jason]

It's possible that the clay layers might form during a slackwater period during spring reversals in river floods. It's also possible the clay layers could have formed under lower water table conditions during lower sea levels when the caves would had negligible flow in them (and wouldn't have functioned as springs)... Some of the clay layers are curiously capped by a hard, orange 'cemented' layer (have a look at the floor in Devil's between the Keyhole and the Hill 400 - in places this is coated by a black manganese oxide - but if you brush it off, you can see the orange crust underneath) - but we haven't analyzed it yet.

I wouldn't expect their to be seasonal differences reflected in the clays because most of the springs do not have seasonal variations water chemistry.

[LCF]

I was curious about this, because I knew that red colors generally indicate the presence of iron oxides, and the limestone that comprises the walls of the cave isn't an iron-rich (or red) stone. In addition, as far as I know, the Mill Pond caves don't have big reversals to siphons (Hole perhaps excepted, but this red stuff wasn't in Hole).

It was an EXTREMELY interesting and instructive experience that Rob described to us ahead of time. Interesting, because I have swum through areas in MX that were that small, and when we turned around, there was just a touch of haze in the water. This fluffy red stuff was far more unforgiving, despite the fact that we were warned, and that I was taking extreme care to be on my very, very best behavior going in. I'm glad I did it, because I'll know better than to enter anything that small in FL, unless I'm prepared for a zero viz exit.

[RN]

Lulz, I know where that is it gets pretty after a bit..

Bet you don't... See below.

Is this the very first jump at Twin? (before the drop off). This is a beautiful one..

Not that one. That is a beautiful passage, but the composition of the bottom is much different than where we went. In Skiles' passage (the first jump at Twin), the silt is tan/brown, not red. It is a very beautiful passage. A transition occurs in that passage beyond the fissure room where you come into deeper, smaller tunnel. This is where the red clay is located. But we didn't go that way. We went into a different passage that ends up connecting to that one, though.

[Xenia]

Not that one. That is a beautiful passage, but the composition of the bottom is much different than where we went. In Skiles' passage (the first jump at Twin), the silt is tan/brown, not red. It is a very beautiful passage. A transition occurs in that passage beyond the fissure room where you come into deeper, smaller tunnel. This is where the red clay is located. But we didn't go that way. We went into a different passage that ends up connecting to that one, though.

Nice. I hope I will get to see this on the next trip. We did a lot of diving at Twin on the last trip and it was so worthwhile. It is a gorgeous cave. Unfortunately I did not get any good pictures... percolation is bad even if it looks quite clean.

[skip]

So you don't think something within the range of observed flow is enough to account for the deposits? Is there any indication of seasonality in the laminations?

Higher rainfall locally, longer periods of low flow conditions?

or the separation after deposit? stir it up and let it set and things tend to settle in like-kind layers. with millions of years to 'set' would it not layer-out - it is a kind of liquidy solid with some flow to it, right?

skip