Dating a sinkhole collapse

[WVCaver2011]

I was thinking about this in my spare time and was wondering if there's anyway to date how long ago a sinkhole collapsed? I know of a vertical cave that was rumored to still be visibly open back in the 1930's I was curious as to how long ago this sinkhole may have opened up. Maybe science has found a way to do this...

[davantalus]

Open 'er up. Use beer bottle carbon dating. ;)

[cavedoc]

Probably won't help answer your particular question but in the west there are people (well one) who use volcanic ash from dated eruptions to study inflow into sinkholes. I guess you can find identifiable ash layers among the dirt/dust and analyze the ash to identify the eruptions and date when the layer was deposited. Of course it only works with certain morphologies of sink holes. Beer bottle labels might work well too. Will there come a day that archeaologists rely on "Born On" dates?

[Caverdale]

Are there any trees or shrubs growing in the sinkhole soil? Counting tree rings will establish a minimum length of growth time.

[WVCaver2011]

Are there any trees or shrubs growing in the sinkhole soil? Counting tree rings will establish a minimum length of growth time.

Yes there are plenty of trees and shrubs at the entrance. Here are a couple of pictures to kinda show what the entrance looks like and whats around the entrance. In the second photo the entrance is behind me and all the vegitation that you see behind me rings the edge of the bowl that goes into the sinkhole. Sorry I didnt have a picture of the entrance to scale. It measures roughly 9 feet long by 7 feet wide.

[wyandottecaver]

OK, wild semi-educated guess. These look like fast growing species and the younger trees in the middle look like they are younger than the current sink (straight trunks and well below the inner rim) and thus probably 10-20 yrs old. The older trees (50-80 yrs) might be younger or contemporary with the inner rim, but the exposed roots indicates soil loss and thus the likelihood that the inner rim is expanding. They also seem to be below the outer rim. Having grown up on a farm, my theory is that those trees are there because the hole was there, making them good markers to keep a tractor out of the hole. So, something has been there a long time, and its getting bigger.....

Edit: I just actually re-read the first post. Is this a old pit cave now collapsed, or a old pit cave still open? (I noticed the light and gear) If it has collapsed, then that wouldn't be surprising given the obvious soil movement going on.

[WVCaver2011]

The cave is actually still open. I've looked at the soil erosion from time to time and I've noticed over the couple of years i've known this cave, that some of the soil is starting to actually create a second cavity up from the entrance about 10 feet or so. The hole is now a fist sized hole but if you drop a rock in it the rock usually gets to the bottom of the main pit in the photo. I think that the reason this second hole is being created is because there's a large rock separating the large pit from the dirt and since the dirt is weaker that the rock and less stable it would probably erode first. So maybe in a few more hundred years or so the cave may have a hanging boulder (once the lip) after all the dirt is eroded away.

Upon repelling into the cave you would notice that below the lip that you have to cross to go into freehang, there's nothing but void space underneath the soil at the base of these trees. In other words if you were looking toward the trees below the lip going down into the pit, you'd notice that you were walking on nothing but soil that is being held up by roots !!! Amazingly the cave is rather stable other than the entrance. The pit, below this lip, is 60feet to nothing but a talus slope made up of large rocks reaching small boulder size.

[Farrar]

Allen, if you have the opportunity, take a drive down to the Gray Fossil Site in Gray, TN - understood as a 5 million year old sinkhole collapse. The paleontologists there are very friendly and willing to show you around the excavation site.

[WVCaver2011]

Allen, if you have the opportunity, take a drive down to the Gray Fossil Site in Gray, TN - understood as a 5 million year old sinkhole collapse. The paleontologists there are very friendly and willing to show you around the excavation site.

Excellent,

I've never been down to tennessee but would if I ever get down that way I will definately have to check into that. You have any idea how they got the estimated age of the collapse?

[Farrar]

I've never been down to tennessee but would if I ever get down that way I will definately have to check into that. You have any idea how they got the estimated age of the collapse?

I assume index fossils, but Bob Denton mentioned that they have done coring at the site - on which I'd guess they'd use cosmogenic age dating (Be - Al) on the sediments - it's the new cool thing! relatively new atleast...

[WVCaver2011]

That's pretty neato!! They must have had a nice stream or something flowing through that area to create that sediment from 5myo?? I would say that stream is probably feeding into the ground or is underground now?

[Speedemon636]

This is kinda relevant to the subject, are sinkholes generally a 99% pointer to a potential cave shaft? I KNOW there is a cave beneath the ground on my property and have many sink holes.. Some very from about desk size to semi size.. Think I'd have any luck finding a shaft if i were to open some up? Sorry but I'm new to all the caving knowledge and such..

[WVCaver2011]

This is kinda relevant to the subject, are sinkholes generally a 99% pointer to a potential cave shaft? I KNOW there is a cave beneath the ground on my property and have many sink holes.. Some very from about desk size to semi size.. Think I'd have any luck finding a shaft if i were to open some up? Sorry but I'm new to all the caving knowledge and such..

Hello Speedmon,

Your sinkholes that you are talking about are actually closed am I correct? In this case the technical term would be "sinks" since they havent opened up yet. Sinks are not 99% promising that there will be a cave shaft beneath any one of the sinks your looking at. If you get any snow you could possibly check the ground to see if there are any bare spots in or around these sinks. If you find one of your sinks are bare of snow then I would permit a dig if you are willing to find a cave under there. Since you said you have many sinks then I would definately say you have some sorta void system underneath some of these. Sometimes you may have a sink but you'll have to dig a long ways just to see what's creating the sink and sometimes you may dig only a couple of feet. Sometimes there may not be a void at all underneath a particular sink but instead the water leaching through the ground overtime has carried the dirt from that area to other places underground eventually pulling down the surface of the ground making a non-void related sink.

I figure since it's your property you probably searched just about the whole area looking for sinks and possibly sinkholes. If you havent you should go out and look for sinkholes first before permitting a dig.

Do you happen to have any pictures or videos of the property and the sinks that are on the property? Do you know the Group and Formation of rocks on your property? You could look at Bedrock Geology maps of your area to see what kind of rock you have under your property. I think we could help you a little better with some more information about these sinks. Maybe you should also check out your local book on Caves and Karsts of your area if you can get one. Perhaps someone on here from Tennessee may be able to help you further on that.

Well, that's about it!!! Hope I helped a little!!

[Speedemon636]

That did help clarify many things! Thanks! And yes from what i can tell, they are closed but when we get a decent amount of rain, fog will rise from various places on the hillside. The only problem is locating those places. I have indeed searched all over the property and haven't had any luck just looking for some open sinks so I'm starting to dig in promising places. I do not have any videos or pics of them because there is so much land and so many sinks. I'd say there is roughly 80 acres of hillside with sinks sprinkled all over. The cave is known as two names, Shippmans Creek Cave or Nut Cave. There is an entrance to the cave, but it is on our neighbor's property (they own only the first 20ft ) and we own the rest.. Our neighbors are picky about the cave since the water permits their trout farm business.. But anyway, I'll try to take some pics in the next few days and post them. Here is a picture of the main known entrance http://nutcavetroutfarm.tripod.com/ My dad said that there is a bit of info about the cave in Barr's caving book of Tennessee but we don't have one handy..

Thanks again for the info!

-Matt

[WVCaver2011]

That did help clarify many things! Thanks! And yes from what i can tell, they are closed but when we get a decent amount of rain, fog will rise from various places on the hillside. The only problem is locating those places. I have indeed searched all over the property and haven't had any luck just looking for some open sinks so I'm starting to dig in promising places. I do not have any videos or pics of them because there is so much land and so many sinks. I'd say there is roughly 80 acres of hillside with sinks sprinkled all over. The cave is known as two names, Shippmans Creek Cave or Nut Cave. There is an entrance to the cave, but it is on our neighbor's property (they own only the first 20ft ) and we own the rest.. Our neighbors are picky about the cave since the water permits their trout farm business.. But anyway, I'll try to take some pics in the next few days and post them. Here is a picture of the main known entrance http://nutcavetroutfarm.tripod.com/ My dad said that there is a bit of info about the cave in Barr's caving book of Tennessee but we don't have one handy..

Thanks again for the info!

-Matt

I don't know if the fog you are speaking of would actually be in association with the sinks you are speaking of due to the fact that if it was raining then it probably wouldnt be the right temperature for the caves to be fogging to begin with. If it was a really cold rain like just on the border line of freezing rain and it was due to a low pressure system moving in then yes, those areas would most likely be fogging if there is void space allowing the fog to rise out of the cave but I dont think it would be cold enough to rise out, dense enough to see it from a distance like it sounds like you are. I think what you may be seeing is actual fog. Unless you know for certain, check for a steady fog that remains in a fixed position next time like rising out of a hole. If it appears to be rising out from a hole like chimney smoke then it sounds to me like you have a cave!! If not then what you have is probably just fog. It really all depends on the temperature of the cave and the surrounding temperature and pressure of the air outside the cave rather you'll see caves fog or not.

As for the digging, I have no right to tell you not to dig on your own property but I'm certain that your neighbor wouldnt take to kindly to this action and I'm sure the cave biota wouldnt either. In fact it looks like the cave is an underwater (at least the entrance) cave as I can see in the picture that you posted. I'm not for sure what your plans are with the cave rather its to go caving or just to say you have an entrance on your property and it's none of my business but I would advise first to at least try to find a caver whom is familiar with the area to help you ridge walk and look for caves. Trust me, if you have 80 acers of land to cover you're definately not going to cover every hole there is to find. I've met a few land owners in the past who said there were absolutely no caves on there property and within about 2 hours of walking through the woods I found a hole and sure enough it was a cave.

Perhaps you should make another topic about ridgewalking on your property and maybe some cavers will come out and help you look around for sinkholes if you would like them to!! I sure would if I lived close by!!!