The coordinates above will take you to this cool geologic
feature you see below.
So what is a rock house you might ask. Rock Houses are formed
in sedimentary rock when water leaks through the horizontal joints
running parallel to the cliff face. In the cold months this water
freezes and expands. As the water expands, it pushes the layers of
rock apart. That’s why if you look in the rock house, the rocks you
see laying on the ground are in almost perfect geometric
shapes.
A cave on the other hand is natural underground void large
enough for a human to enter. Some people suggest that the term
'cave' should only apply to cavities that have some part which does
not receive daylight; however, in popular usage, the term includes
smaller spaces like sea caves, rock shelters and grottos.
Speleology is the science of exploration and study of all aspects
of caves. Exploring a cave for recreation or science may be called
"caving", "potholing", or occasionally (only in the United States)
"spelunking".A naturally formed opening beneath the surface of the
Earth, generally formed by dissolution of carbonate bedrock. Caves
may also form by erosion of coastal bedrock, partial melting of
glaciers, or solidification of lava into hollow tubes.
So there you have it, what you se infront of in what most
people think as a cave but a little diiference of formation makes a
new geologic site to visit.
For most areas in Tennessee, a fairly limited range of rock
types is present. In fact, of the seven major provinces, only the
Unaka Mtns. contain non-sedimentary rocks. One of the most
important influences on a sedimentary rock's resistance to erosion
is its quartz content. The more quartz a rock contains, the more
resistant it will be to erosion. In Tennessee, sandstones generally
consist mostly of quartz. Siltstones and shales (i.e. "fine grained
[f.g.] clastics" ) are usually admixtures of quartz and other less
resistant minerals. Limestones (i.e. "carbonates"), of course, are
composed of calcite, which is rather susceptible to chemical
weathering. However, some carbonate rocks do contain a fair amount
of quartz -- especially in the form of chert -- and can be a bit
more resistant to erosion than their more pure relatives. In
addition, the carbonate rock dolomite is generally somewhat more
resistant to erosion than limestone. Another equally important
characteristic is how well the grains of a rock are consolidated --
known as its induration. Well indurated rocks have either
intergrown crystals, or the grains are joined together with a lot
of intergranular cement. Most limestones are initially well
indurated. The induration of sandstones, siltstones, and shales
(i.e. "clastics") varies from outcrop to outcrop. In addition, over
time, weathering may dissolve the cement and weaken the rock.
Quartz cements are very resistant to dissolution. Calcite cements
dissolve rather readily. Iron oxides and clay minerals are fairly
susceptible to chemical alteration. As a result of these two
factors -- composition and induration -- sedimentary rocks display
a wide range of susceptibility to erosion. Generally,
well-indurated quartz sandstones are the most resistant to erosion.
Likewise, limestones and poorly indurated shales are the most
susceptible to erosion. Other sedimentary rock types are a bit more
difficult to place within this spectrum. For example, all else
being equal, a moderately indurated siltstone would probably be a
bit less resistant to erosion than a moderately indurated
conglomerate -- unless the siltstone has quartz cement and the
conglomerate has calcite cement. Then the rates of resistance would
be reversed.
Unaka Mountains: Because the bedrock here consists of a variety
of igneous and metamorphic rocks, it is typically rather resistant
to erosion. As you might expect, some rock types erode more readily
than others, so significant relief (i.e. rugged topography; steep
slopes) is evident nonetheless. However, due to (1) resistance of
these rocks to erosion, (2) uplift associated with the orogenies of
the past, and (3) subsequent isostatic movements, the elevation
throughout this area is generally 1000's of feet above sea level.
Note: my cross-section transects an area of the Unakas with
relatively low elevations (2000 ft. or so).
To claim credit for this earthcache you must do the
following: 1.) Take a picture of you and your gps at the posted
site. 2.) Tell me how high and wide the rock house or cave is?
3.)Id one type of sedimentary rock at the site.