We are looking at buying land in Dekalb county. There are 3 sinkholes a few feet deep and maybe 7-10 feet wide. It is on a small “mountain”, a few streams flow down this hill as well as there is a cave at the bottom where the water is gathered from in a cistern. Are these dangerous? Is it bad to buy land with sinkhole activity like this? I’m worried, but everyone tells me they are normal in TN.
It's pretty normal in Tennessee which has more caves than any other state in the U.S. In many locations in Middle Tennessee, there is no way to escape karst because it is all underlain by limestone. One thing you can do is go back and look at older aerial photographs to see if the sinkholes were there in their current configuration. If so, they are probably pretty stable. If there is a lot of soil and vegetation growth in the sinkhole itself, that may be further proof of its stability.
@@thegroundwaterguy -- I thought Florida had the Number #1 spot with Tennessee ranking farther down the list, something like #10 maybe?? According to Thomas C. Barr, a State Geologist for TN, wrote a book called "Caves of Tennessee," or something like which was published in 1958. According to his book, there could be many more Caves that were NOT KNOWN at the time. Out of TN's 95 Counties, Warren County had the most number of Caves. My home County, Overton County, ranks #2 in number and farther East, I believe it is Scott & Morgan Counties that are TN's only 2 Counties without Caves. I assume that may be due to the presence of Pennsylvanian Sandstone (& Shale) Outcrops versus the Mississippian Limestones. I have noticed that there "generally" doesn't seem to be Caves in Counties where Coal Mines have existed. Would you agree with that? Overton County seemed to have been an exception when the Mines were running with the Southeast corner's different Geology. Mr Barr had also written a 2nd Book on the Caves of TN, probably around 1972. I was really impressed with the Caves' descriptions he gave.
@@brucewinningham4959 The coal occurs in Pennsylvanian sandstone and shale sequences, so no cave development in those formations like you get in limestone. Generally the highest concentrations of caves in Tennessee are along the western margin of the Cumberland Plateau where it meets the eastern Highland Rim. That belt is generally referred to as "the sinkhole plain" due to the density of sinkholes and well developed karst, including caves. You do get deeper Mississippian limestone formations below the Pennsylvanian sandstone and shale sequences, but they are generally too deep for karst development except where they are exposed along the margins of the Cumberland Plateau. Generally, karst is going to develop best at less than 300 feet.
Very interesting topic you are speaking on. Does Karst have much effect on Geohazards such as "Mass Wasting" and "Rock Slides?"
It can, but generally the geohazards associated with karst terrain are sinkholes.
We are looking at buying land in Dekalb county. There are 3 sinkholes a few feet deep and maybe 7-10 feet wide. It is on a small “mountain”, a few streams flow down this hill as well as there is a cave at the bottom where the water is gathered from in a cistern. Are these dangerous? Is it bad to buy land with sinkhole activity like this? I’m worried, but everyone tells me they are normal in TN.
It's pretty normal in Tennessee which has more caves than any other state in the U.S. In many locations in Middle Tennessee, there is no way to escape karst because it is all underlain by limestone. One thing you can do is go back and look at older aerial photographs to see if the sinkholes were there in their current configuration. If so, they are probably pretty stable. If there is a lot of soil and vegetation growth in the sinkhole itself, that may be further proof of its stability.
@@thegroundwaterguy -- I thought Florida had the Number #1 spot with Tennessee ranking farther down the list, something like #10 maybe??
According to Thomas C. Barr, a State Geologist for TN, wrote a book called "Caves of Tennessee," or something like which was published in 1958.
According to his book, there could be many more Caves that were NOT KNOWN at the time. Out of TN's 95 Counties, Warren County had the most number of Caves. My home County, Overton County, ranks #2 in number and farther East, I believe it is Scott & Morgan Counties that are TN's only 2 Counties without Caves. I assume that may be due to the presence of Pennsylvanian Sandstone (& Shale) Outcrops versus the Mississippian Limestones.
I have noticed that there "generally" doesn't seem to be Caves in Counties where Coal Mines have existed. Would you agree with that? Overton County seemed to have been an exception when the Mines were running with the Southeast corner's different Geology.
Mr Barr had also written a 2nd Book on the Caves of TN, probably around 1972. I was really impressed with the Caves' descriptions he gave.
@@brucewinningham4959 The coal occurs in Pennsylvanian sandstone and shale sequences, so no cave development in those formations like you get in limestone. Generally the highest concentrations of caves in Tennessee are along the western margin of the Cumberland Plateau where it meets the eastern Highland Rim. That belt is generally referred to as "the sinkhole plain" due to the density of sinkholes and well developed karst, including caves. You do get deeper Mississippian limestone formations below the Pennsylvanian sandstone and shale sequences, but they are generally too deep for karst development except where they are exposed along the margins of the Cumberland Plateau. Generally, karst is going to develop best at less than 300 feet.