2017/12/29

Tennessee County High and Low Points

View from Clingmans Dome, Clingmans Dome lookout tower, Great Smoky Mountains National Park, Sevier County, Tennessee 1

Using quick and dirty analysis with a 10M Digital Elevation Model (DEM), I produced this dataset which shows the high and low points for each county. The highest point in Tennessee (as any native would know) is in Sevier County at Clingmans Dome, at 6644.33' The lowest point is in Davidson County at a Vulcan Materials quarry at just 90.18' above sea level. Of course, this doesn't include locations that are underground, so let's qualify that this is the lowest point that is not underground. Below is the table if you want to look at your home county.

CountyHigh Point MapHigh Point ElevationLow Point MapLow Point Elevation
Anderson36.198101,-84.2301383527.8736.021527,-84.324953757.79
Bedford35.659490,-86.3043981355.8335.578287,-86.637268630.75
Benton35.852453,-88.206064683.9636.018287,-88.003935338.01
Bledsoe35.743564,-84.9913422680.9535.434861,-85.335046707.66
Blount35.568564,-83.706255526.0535.874212,-84.009953803.36
Bradley35.149027,-85.0239351492.8735.278101,-84.747638674.45
Campbell36.198009,-84.2303243527.5736.223564,-84.092916831.69
Cannon35.866064,-85.9761572094.8135.832546,-86.178472592.91
Carroll35.855509,-88.237731710.8936.062083,-88.691064324.19
Carter36.104768,-82.1223616284.0536.374490,-82.2955091388.81
Cheatham36.127268,-87.021990910.6236.368657,-87.250138356.41
Chester35.453287,-88.463287742.6135.464490,-88.683101365.37
Claiborne36.569120,-83.8352313205.1836.375787,-83.4506941014.49
Clay36.588472,-85.4718981409.6536.558009,-85.498472484.78
Cocke35.715046,-83.2555096351.1336.001064,-83.237268994.73
Coffee35.454120,-85.8938422025.9935.465046,-86.246620787.82
Crockett35.837638,-89.263842484.0735.992824,-89.190694269.90
Cumberland35.781157,-84.9784723053.7435.825509,-84.781805869.10
Davidson36.064675,-86.7838421158.9836.125601,-86.92254690.18
Decatur35.495601,-88.021157707.7635.663287,-88.025138345.94
DeKalb35.845509,-85.8920831327.6836.107453,-85.851805473.00
Dickson36.107546,-87.426435963.8136.328287,-87.231805357.96
Dyer36.141527,-89.381435512.2235.923472,-89.643842229.51
Fayette35.039027,-89.220972671.7535.31125,-89.632916248.85
Fentress36.155416,-85.0843981871.4736.453472,-85.088472649.64
Franklin35.219398,-85.8872682033.1834.98875,-85.899120616.89
Gibson35.808194,-88.755138573.5436.014953,-89.194305269.88
Giles35.456064,-87.1291201169.9834.997731,-87.030509558.54
Grainger36.375046,-83.3461572518.8036.089305,-83.659953849.11
Greene36.061342,-82.6274534853.9136.180509,-83.1658791023.19
Grundy35.320694,-85.5631012383.6235.525324,-85.681712871.39
Hamblen36.227453,-83.3326381953.4536.125046,-83.235509998.11
Hamilton35.003842,-85.3455092152.0035.064027,-85.189675454.15
Hancock36.423287,-83.1968982628.9336.413472,-83.3856941077.27
Hardeman35.139675,-89.138287693.7535.423194,-89.087361309.65
Hardin35.058194,-88.001157844.6635.244583,-88.168009316.15
Hawkins36.408101,-82.7069903117.4936.312824,-83.2385641063.98
Haywood35.398009,-89.185972502.8935.575509,-89.498009254.51
Henderson35.500601,-88.440601704.9735.624398,-88.247453372.84
Henry36.385787,-88.297453652.8436.298657,-88.144953343.82
Hickman35.931157,-87.303379982.9335.898563,-87.690970372.19
Houston36.190787,-87.579398864.7636.250509,-87.924583355.39
Humphreys36.137638,-87.552175888.4635.966342,-87.992731347.96
Jackson36.398009,-85.5271751131.6336.309490,-85.750138496.76
Jefferson35.901064,-83.2981013632.7036.058194,-83.694120833.88
Johnson36.338009,-81.7063425503.5136.340138,-81.9997681955.74
Knox36.111990,-83.7665272090.5135.944768,-83.914305603.07
Lake36.419212,-89.453009325.8036.444583,-89.383287137.21
Lauderdale35.833194,-89.479490526.3335.542546,-89.907453208.89
Lawrence35.434675,-87.2235641101.8135.008657,-87.574768513.42
Lewis35.490694,-87.2768981074.7935.618842,-87.447268569.55
Lincoln34.997824,-86.3223611515.2335.092268,-86.820787597.60
Loudon35.710416,-84.1793051322.3635.885046,-84.300324736.14
Macon36.429027,-85.8973611101.2236.439027,-86.110416498.01
Madison35.699305,-88.610231663.6735.688564,-89.069120303.57
Marion35.318564,-85.558752385.6634.998287,-85.720046589.58
Marshall35.403657,-86.7261571288.9135.592824,-86.836712582.62
Maury35.459398,-87.1299531175.6635.715601,-87.255138499.55
McMinn35.273194,-84.5097682344.6235.471898,-84.635972663.27
McNairy35.288101,-88.534305688.0134.995416,-88.723194357.17
Meigs35.529490,-84.7186571296.0635.484490,-84.875046680.49
Monroe35.309212,-84.0266205465.1435.495324,-84.249490807.00
Montgomery36.33375,-87.432361811.2636.422453,-87.587731342.32
Moore35.342083,-86.5304161266.3935.143472,-86.369398693.14
Morgan36.107546,-84.4151383339.6335.975972,-84.570046752.01
Obion36.433842,-89.158472552.9036.251990,-89.433842253.71
Overton36.180694,-85.2421752024.3636.344212,-85.496435580.12
Perry35.488935,-87.726064983.5035.590509,-87.999583355.28
Pickett36.583101,-85.0250461789.5536.625138,-85.222083635.91
Polk35.000138,-84.5293054221.9835.225231,-84.628009679.83
Putnam36.100231,-85.2433792058.9536.142175,-85.804675473.39
Rhea35.543564,-85.1020832040.8935.538287,-84.898657583.49
Roane35.866527,-84.7142122033.5435.899212,-84.617175674.52
Robertson36.413287,-86.714305928.5736.554953,-87.132361378.92
Rutherford35.717916,-86.2301381366.3236.000138,-86.457731463.74
Scott36.163564,-84.4413423260.6736.598564,-84.605046794.67
Sequatchie35.372916,-85.3193052393.8335.270601,-85.433009657.28
Sevier35.562824,-83.4985646644.3335.944953,-83.686527837.34
Shelby34.998194,-89.909490491.5834.998657,-90.247731186.33
Smith36.140138,-86.0635641249.7036.249861,-85.926898439.88
Stewart36.344212,-87.781990771.2536.498935,-87.858564333.41
Sullivan36.437361,-82.1297684298.7036.545879,-82.6110641150.04
Sumner36.464768,-86.2479161083.1536.301064,-86.665879402.06
Tipton35.446527,-89.807453457.2235.400601,-90.147731196.23
Trousdale36.424675,-86.2193051104.0336.313287,-86.269953436.87
Unicoi35.989675,-82.4904165503.7136.154675,-82.4414351572.52
Union36.175879,-83.7246752311.6836.172731,-83.927083912.70
Van Buren35.577731,-85.4334722144.1635.818379,-85.430324781.66
Warren35.534768,-85.6131011984.9735.832175,-85.686805644.28
Washington36.217175,-82.3705093548.4736.440231,-82.4384721259.83
Wayne35.218379,-87.7104161086.3735.387175,-87.999768357.30
Weakley36.496527,-88.595046601.7736.217268,-88.953472285.94
White35.87875,-85.3152312009.5035.857361,-85.630046642.88
Williamson35.755509,-86.741251252.3035.902916,-86.896342369.54
Wilson36.069861,-86.1707871368.1536.292546,-86.472083438.46

2017/12/20

Grassy Cove, North America's Largest Sinkhole

Grassy Cove Community Center, Cumberland County, Tennessee

Nestled in the southeastern part of Cumberland County, Tennessee lies a quite community known as Grassy Cove. Its flat fertile land is home to scenic farms and farmland which are still owned by the descendants of the first European inhabitants of the area.

Without looking more closely at the landscape, it might escape the casual viewer that one was sitting inside a giant bowl. But with the aid of maps, it becomes readily apparent that Grassy Cove isn't like a regular hollow.

My first rule as a geographer is "Ask a local". Locals know a lot. For example, it's long been known that if it rains too much in Grassy Cove, then the flat farmland turns into a lake. It's also known from the days of yore that discarded corn shucks in the cove will appear in the Sequatchie River a few miles away, a few days later. What's going on here?

Grassy Cove flooding, Cumberland County, Tennessee 2  

Structurally, there's a lot to be said about Grassy Cove; it's not just a simple sinkhole. Its formation is the middle stage of a grand weathering process, with hints of its beginning and end observable along the axis of Sequatchie Valley Anticline, a giant geomorphological feature that spans two states. The Sequatchie Valley Anticline is a remnant of the same compressional forces which created the ridges and valleys in the physiographic province of the same name east of Grassy Cove. The Sequatchie Valley Anticline is a huge structural deformation where the bedrock was folded. Imagine a carpet getting scrunched up; the spots where it bends upwards are anticlines, downwards are sinclines.

Anticline, Sequatchie Valley, Cumberland County, Tennessee


The anticline has been around for a really long time, slowly being weathered away. The erosion process means that it is retreating northward, so features at its northern extent may offer a glimpse into what happened further south longer ago (that is what is happening now in Grassy Cove). And it also lets us see what the future of Grassy Cove is (to be part of the Sequatchie Valley).

Currently though, Grassy Cove is drained completely through a cave system and the water from there emerges at Devilstep Hollow, at the head of the Sequatchie Valley. 

Devilstep Hollow Cave, Head of Sequatchie Unit, Cumberland Trail State Park, Cumberland County, Tennessee 2


As stated, this is the largest sinkhole in North America (which I am aware of). Back in 2013 Tom Dunigan and I crunched some numbers for sinkholes in Tennessee. I made areal and volumetric estimates based on 10m Digital Elevation Models (DEMs). Now, 2.5' DEMs area available, which are 172 times more detailed than the 10m DEMs. I wanted to make a renewed comparison and try to tease out more detailed information.

Map of Grassy Cove, Cumberland County, Tennessee

Below are the updated figures for the region based on the 3DEP lidar.


Region Measure                 Value Unit
Watershed Area 33.17 Kilometers2
Watershed Perimeter 42.15 Kilometers
Sinkhole Area 13.31 Kilometers2
Sinkhole Perimeter 35.71 Kilometers
Sinkhole Major Axis 7.67 Kilometers
Sinkhole Minor Axis 4.36 Kilometers
Sinkhole Axial Declination 30.80 Degrees
Sinkhole Minimum Elevation 467.27 MASL
Sinkhole Maximum Elevation 507.24 MASL
Sinkhole Depth 39.97 Meters


Overlook, Grassy Cove, Cumberland County, Tennessee 1

2017/12/12

Sandstone Boxwork

Sandstone boxwork is a unusual phenomenon that we see on the margins of the Cumberland Plateau.

There are three things that must happen first to produce boxwork.
    Jointing
    Mineralization
    Weathering

Photo credit: Brian Solomon / @waterfall_hillbilly


Jointing

Produced in a parent rock of sandstone, this type of boxwork originates as small joints which run in a box shape. The origins of these joints could be from frost wedging - where water in the rock freezes and cracks the rock, or it could unloading pressure from the rock de-watering, or it could be from some other physical process. The origins of the boxwork joints are still a bit of a mystery to me.


Mineralization

The joints become a place of preferential mineralization. Groundwater loaded with iron minerals moves through the pores of the sandstone. Where it finds a void, like in the joints, it tends to drop minerals out of solution. The rust colored minerals you find on your water heater at the house are chemically quite similar to this boxwork. 


Weathering

The joint surface must first be exposed to weathering, whether by cliff failure, slump, or some other wasting process. The exposed surface's sandstone weathers out first, leaving in place the mineralized boxwork. Because the sandstone around it is removed, the boxwork tends to protrude after its been well developed.


Similar Features

Boxwork is a type of Liesegang ring. Liesegang rings lack obvious structural control, as in they do not have joint influenced development.

Painted Rock, Painted Rock Cave, Big South Fork NRRA, Fenress County, Tennessee Liesegang rings, Rockcastle conglomerate, Eagle shelter, White County, Tennessee 2 Liesegang rings, Claire Murphy, Fentress Formation, Big South Fork NRRA, Scott Co, TN

2017/10/23

KTAG - Cave Density Map


Caves of Kentucky, Tennessee, Alabama, and Georgia (KTAG)
This is a map showing the density and distribution of caves in Kentucky, Tennessee, Alabama, and Georgia (KTAG). The strong line of density extending north-east from the intersection of Tennessee, Alabama, and Georgia shows the western escarpment of the Cumberland Plateau where Mississippian aged limestones outcrop and are exposed to weathering processes.

At the southern end of the Cumberland Plateau it becomes more heavily dissected, with islands of Plateau present amidst the Highland Rim. Along the margins of these islands caves can be exposed, which explains the dispersion at the southern extent of the Plateau.

Central and Western Kentucky show a secondary area of cave density; a ring of Mississippian aged carbonates has been exposed from the weathering of the Cincinnati Arch. Mammoth Cave resides in the densest part of this region.

This map was created using data from the following sources:

  • Alabama Cave Survey (ACS)
  • Georgia Speleological Society (GSS)
  • Kentucky Speleological Society (KSS)
  • Tennessee Cave Survey (TCS)

ArcMap 10.3 by ESRI was used to create the map. Workflow follows.

· For Tennessee, Alabama, and Georgia

  • Tabular data joins in Access, output to Excel table
  • Format Excel tables by converted DMS to DD
  • Reference E1 (only one entrance per cave; the first documented entrance) points
  • Spatially join points to county feature class and display count as label
  • Kernel Density

· For Kentucky

  • Summarize county table and tabular join to county feature class and display count as label
  • Summarize 7.5' quadrangle table and tabular join to 7.5' quadrangle feature class
  • Feature to point (create centroid) of quadrangle feature class; preserve count attribute
  • Kernel density with new quad centroid feature class with count as Z attribute



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2017/10/17

Kentucky Cave Distribution Map, 2017

Kentucky Cave Distribution including Karst Geology, 2017 This map represents the generalized distribution of cave entrances in Kentucky based on data from the 2017 release of the Kentucky Speleological Society (the data is generalized by 7.5 minute quadrangle). A few easily observable patterns exist and are worth description.

The line of density which extends northeast / southwest shows the margin of the Cumberland Plateau where Mississippian aged limestones outcrop.

The ring of density west of there is the Inner Bluegrass Karst region where erosion of the Cincinnati Arch has exposed Middle Ordovician carbonates. The dense area centered at Edmonson, Hart, and Barren counties represents the Mammoth cave region and the caves of the Pennyroyal plateau. Mammoth Cave is still the world's longest cave, with a newly announced length of 412 miles.

The most cave entrance dense quadrangle recorded is Johnetta in Rockcastle County, but this is likely only sampling bias. This bias could occur because caves are easier to get to, or more likely because cavers are active in that area. Another possible example of sampling bias is in Carter County, which has been the focus of cavers and of much documentation. This may account for its high totals versus other limestone rich areas. To this end, this map serves as wonderful tool to generate the next areas of exploration, as we see several limestone areas that seem to have few caves.

Overall, Kentucky has 4,939 documented caves, and 5,547 documented cave entrances (some caves have more than one entrance). Data from the Kentucky Speleological Survey (KSS) comes from cavers and scientists, and has been collected and compiled since 2000.

Thanks Howard Kalnitz for the assist on this write up!

2017/09/25

Tennessee Caves 2017

Tennessee Caves 2017
With the Fall data release of the Tennessee Cave Survey (TCS) comes the updated Tennessee cave distribution map. I've been producing these maps yearly since the TCS began digitally distributing their data in 2008. In that time my maps and my skill as a map maker have changed dramatically.

This year 153 new caves were added, and 42 caves removed. Caves get removed either because they have been re-measured since discovery and shown to fail to qualify for the survey (50' horizontal, 30' vertical), or the cave is connected to another known cave and two or more caves become one cave.

In other news White County is still way out in the lead with 1,250 unique caves. The majority of caves in Tennessee occur at a specific geologic contact, and that particular contact is well exposed in White County.

2017/09/13

Public Lands of the Upper Cumberland

Welch Point, Bridgestone Firestone WMA, White County, Tennessee 13 Below you'll find a reasonably complete listing of state and federal public lands in the Upper Cumberland region. Some locations may be closed to the general public, so please refer to their website prior to visiting to ensure a safe and enjoyable trip.

US Army Corps of Engineers Reservoirs Website
Center Hill Lake Website Photos
Cordell Hull Lake Website Photos
Dale Hollow Lake Website Photos
Old Hickory Lake Website
National Park Service Lands Website
Big South Fork National River & Recreation Area Website Photos
Obed Wild and Scenic River Website Photos
State Forests Website
Bledsoe State Forest Website Photos
Pickett State Forest Website Photos
Scott State Forest Website
Standing Stone State Forest Website Photos
TDEC Managed Lands Website
Big Bone Cave Designated State Natural Area & National Natural Landmark Website Photos
Burgess Falls Designated State Natural Area Website Photos Map
Colditz Cove Designated State Natural Area Website Photos Map
Cordell Hull State Historic Park Website Photos
Cumberland Mountain State Park Website Photos
Cumberland Trail State Park Website Photos
Cummins Falls State Park Website Photos
Edgar Evins State Park Website Photos
Fall Creek Falls Designated State Natural Area Website Photos
Fall Creek Falls State Park Website Photos
Hubbard's Cave TNC Preserve Designated State Natural Area Website Photos
Lost Creek Designated State Natural Area Website Photos Map
Morrison Meadow Designated State Natural Area Website
Ozone Falls Designated State Natural Area Website Photos
Pickett State Park Website Photos Map
Pogue Creek Designated State Natural Area Website Photos
Rock Island State Park Website Photos Map
Sgt. Alvin C York State Historic Park Website Photos
Short Mountain Designated State Natural Area Website Photos
Standing Stone State Park Website Photos
Twin Arches Designated State Natural Area Website Photos
Virgin Falls Designated State Natural Area Website Photos
Washmorgan Hollow Designated State Natural Area Website Photos
Window Cliffs Designated State Natural Area Website Photos Map
Tennessee Valley Authority Reservoirs Website
Great Falls Lake Website Photos
TWRA Managed Lands
Website
Alpine Mountain Website Photos
Anderson Pond Website
Big South Fork N.R.R.A. Website Photos
Blackburn Fork Website Photos
Bridgestone/Firestone WMA Website Photos
Catoosa WMA Website Photos
Centennial Wilderness Website Photos
Cordell Hull Refuge Website
Cordell Hull WMA Website
Edgar Evins SP & WMA Website
Fall Creek Falls SP & WMA Website Photos
Hampton Crossroads Website
Headwaters WMA Website
Jackson Swamp Website
Keyes-Harrison WMA Website
Luper Mountain Website
Mt. Roosevelt WMA Website Photos
Pea Ridge WMA Website
Pickett SF & WMA Website Photos
Scotts Pinnacle Website Photos
Skinner Mountain Website
Standing Stone SF & WMA Website Photos
The Boils Website Photos