Showing posts from 2017

Tennessee County High and Low Points

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. County High Point Map High Point Elevation Low Point Map Low Point Elevation Anderson 36.198101,-84.230138 3527.87 36.021527,-84.324953 757.79 Bedford 35.659490,-86.304398 1355.83 35.578287,-86.637268 630.75 Benton 35.852453,-88.206064 683.96 36.018287,-88.003935 338.01 Bledsoe 35.743564,-84.991342 2680.95 35.434861,-85.335046 707.66 Blount 35.568564,-83.70625 5526.05 35.874212,-84.009953 803.36 Bradley 3

Grassy Cove, North America's Largest Sinkhole

Grassy Cove Community Center with Brady Mountain visible behind it. Nestled in the southeastern part of Cumberland County, Tennessee lies a quiet community known as Grassy Cove. Its flat fertile land is home to agriculture and scenic farms 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 any old hollow. My first rule as a photographer/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 fertile bottomland 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 flooded. Structurally,

Sandstone Boxwork

Photo credit: Brian Solomon / @waterfall_hillbilly Photo credit: Bryan Melton 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 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. If the following steps occur without previous jointing then one gets Liesegang Rings. 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

KTAG - Cave Density Map

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 Spele

Kentucky Cave Distribution Map, 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 lik

Public Lands of the Upper Cumberland

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 T