Sunday, February 27, 2011

Fern Bridge

Gray's Arch in the Red River Gorge and is a sandstone arch
     The Swift Legend is popular over several states and in Eastern Kentucky from border to border.  My personal experience, as noted in previous entries, is in and around the Red River Gorge area.  Others refer to the legend in other notable areas of the state. And of course, other sites that are encouraging are found in East Tennessee, Virgina and North Carolina to mention a few.  The Swift Legend has also been linked to the Carter County area of Kentucky. This is a good spot because of so many caves and great rock formations. One of my favorites is the Fern Bridge located right on Carter Caves State Resort Park.
The Rock House is formed in Limestone
     What makes the Fern Bridge so outstanding is that it is formed out of two distinctly rock types.  You see there basically are two kinds of natural bridges or arches found in Kentucky.  First, and the most notable, are the sandstone/conglomerate arches.  Natural Bridge, Sky Bridge and this one, Gray's Arch, all are formed from the weathering away of individual sand grain sized pieces of quartz.  After tens of thousands of years of weathering by wind, water and freezing, the arches are carved out by nature.  Now there are sandstone arches by the thousands in the Red River Gorge.  Another popular spot for these arches is in McCreary County in Southern Kentucky.  The Natural Arch, Koger Arch and the Buffalo Arch are famous in that part of the state.
Fern Arch is formed in both sandstone (upper part) and limestone
     The second type of arch is formed in limestone.  The process of formation is altogether different than the sandstone arches.  This type is formed the same way caves are formed by the slow dissolving of the rock by carbonic acid in the water running over and around the rocks.  There are some in the Red River Gorge, and massive ones on Carter Caves State Park.  And there are even isolated ones around the state such as the famous Rock House in Russel County.
The contact between sandstone  (upper half of photo) and limestone
     But what I like about the Fern Bridge at Carter Caves, aside it being the fifth longest natural arch spa n in the east of the Rock Mountains, is that it is formed  in BOTH sandstone and limestone.  If you look closely at the picture you can actually see the different rocks and the contact point.  So both arch forming processes had to have occurred at this site in order for this big guy to exist.  This is the only arch I am aware of that is formed both in sandstone and limestone.  There may be another, but I have not seen it yet.
     Now what does this all have to do with the Swift treasure? Well, there are just a lot of odd and strange things out there all across the state. I've noted earlier some other strange geological oddities and here we have another.  Could it be so strange that there is a yet to be discovered treasure hidden, just off the path, somewhere in the hills?
    Finally, if you like to read about unusual stuff in our great state, Unusual Kentucky is a great site!  Check it out.

Monday, February 7, 2011

The Strange Case of Bell Falls

Channel fill outcrop along Red River at Bell Falls
     I've noted in previous comments some of the oddities regarding Kentucky geology.  Contrary to popular belief not all of Kentucky's geological treasure is sedimentary rock deposits of limestone, coal and shale. Case in point is the igneous intrusion of Elliot county.  There could be others hidden below the surface.  There is another kind of strange deposit that geologist commonly call channel fills.  These are rock formations that appear to be a mixture of rocks all jumbled about without any sign of normal sedimentary stratification.  They appear almost like a creek or river bottom with stones rolled and tumbled along.  A channel fill is just exactly that, it is thought. If one can imagine that ancient streams, perhaps millions of years old, eroded down through the formed sedimentary rock from yet farther back in time.  As the stream cut and gouged its way down into the rock it naturally carried stones, dirt sand etc from its source and deposited, just like modern streams, along the bottom. When enough time passed, and for whatever reason, the streams stopped and through eons of time more sediments continued to build up over the now dead stream channel, the stream bed is simply frozen in time among the rock strata.  It's also possible, depending on the streams source, that in those bottom stream deposits are minerals that are not common to the regular rock strata that now surrounds the ancient stream channel.  Yes, there could be placer gold and silver as well as a host of other minerals though none have been found.  Many years ago, some prospectors claimed to have detected uranium or some type of  heavy metals in the deposit, but nothing ever came of it.
Broken rock fragments in outcrop shown above
    The Bell Falls is a beautiful waterfall that flows most of the year and during the spring the woodlands around the falls exhibit a spectacular array of wildflowers.  It is located along highway 715, the popular gorge drive.
Bell Falls in Red River Gorge

Swift Interview

    Just a quick update as promised. The Swift interview will air May 21 at 8:00 PM on KET. The last entry on this site covered the intervie...