The Quarry on Menelaus Road EarthCache
The Quarry on Menelaus Road
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The Quarry on Menelaus Road
HISTORY: OPEN CUT MINING
The abundance in Kentucky of limestone formations close to the
surface where small hills rise presents many sites where horizontal
open cuts, or quarries, may be found. The expense of
transporting large, heavy stone blocks combined with the large
number of potential quarry sites has kept the size of individual
quarries small until relatively recently in our history.
Quarries make up in number what they lack in size. That is
why you can find a number of very small quarries widely scattered
about this locality in Central Kentucky. This quarry is in
the region known as the Knobs. Historically, the exploitation
of mineral deposits from copper to iron ore has for the most part
required underground operations. Yet where conditions are
suitable, and the deposits do not occur too far below the surface,
open pit methods have proved very efficient for local needs.
This was especially true for our area during the time of
settlement, of the quarrying of limestone used for houses, the
field walls of farms, and bridge piers and abutments. An
example of this use is a nearby stone fence made from limestone
blocks -- it is pictured below, and you can find it just 0.2 miles
east of the quarry at N37° 38.960' W084° 18.246'.
Open cut techniques used on the frontier had the advantage of
lowering labor costs, as well as increasing safety, when compared
to underground mining of stone. Among the advantages of open
cut mining are the obviation of tasks such as sinking a shaft,
tunneling, and timbering for support. Nor is there a need for
artificial lighting or ventilation. A large disadvantage is
the removal of waste material, called "overburden," from the quarry
site. Prior to the development of mechanized means of
breaking, loading, and hauling away large amounts of undesired
material from the quarry site, limits were quickly reached as to
how large an open cut operation could grow. Since most local
quarries operated intermittently, even a small quarry would see a
lifetime measured in decades.
Quarry men at work (not at this quarry, though)
This site is an excellent example of the type of quarry used for
local stone production until as late as the late 1800s to early
1900s. The cut has been made into the side of a low hill,
with the quarry's lowest level being even with that of the
surrounding terrain. Typically, it took at least two strong,
brave men to quarry stone. One to hold the drill and turn it,
the other to drive it in with a sledgehammer. Once the holes
were deep enough, wedges were driven in to split the rock.
Then the rough limestone blocks had to be loaded onto a wagon or
sledge and taken to the building site where they would be shaped to
fit. It was dangerous and demanding work. Thankfully,
fences are no longer made from quarried stone or field stone.
Today's civil engineering projects such as bridges use reinforced
concrete which calls for volumes of crushed stone a hand operated
quarry could never hope to meet. Modern commercialization of
stone production has lead to the development of extensive
underground mines for limestone. Today most limestone is
crushed to provide stone for aggregate, agricultural limestone, and
for cement and asphalt. And Kentucky is among the top 10
producers of limestone in the country. Times have changed,
and we are left with these small reminders that may pleasantly
surprise us as we are driving down an old country road. They
are reminders of an age when progress was slowly made using hand
labor, horses, lots of sweat and sometimes blood.
Two works made from limestone are shown
below:
A nearby stone fence
The Great Pyramid
GEOLOGY
Across Kentucky, natural outcrops and man-made excavations have
exposed layers of rock strata. To a geologist, these layers
are like the pages in a book, and each tells a part of the geologic
story of Kentucky. Almost all of the rocks exposed at the
surface of the State are sedimentary rocks. Sedimentary rocks
are layered, and can often be traced across broad distances at the
surface and beneath the surface. Geologists can determine the
relative age of sedimentary rock layers from the fossils they
contain. Similar layers can be grouped into units of strata,
just as pages are combined into chapters in a book.
Kentucky in Geologic Time
On the geologic map below, each color represents a different age,
or chapter in Kentucky's geologic history. These are very
large groupings of rock strata based on the geologic time
scale.
Although on the map it looks as though each rock unit or chapter
stops where the next begins, older units actually dip beneath
younger units. So on the map above, the Ordovician strata is
exposed in the center of the State, but continues beneath the
surface in the areas where Silurian and Devonian (and younger)
strata occur at the surface. Likewise, Ordovician through
Devonian strata continue beneath the areas where Mississippian
strata occur at the surface, and so on. Each of the periods
colored on the map may contain several hundred to thousands of feet
of rock strata. Geologists divide these larger time-based
units into smaller, mappable rock-based units called groups.
Groups can be divided into smaller units called formations (each
tens to hundreds of feet thick); formations may be divided into
smaller units called members (usually tens of feet thick); and the
smallest units are beds, which usually represent a distinctive
layer of rock.
The Devonian Period
Devonian Strata
On the geologic map of Kentucky, Ordovician and Silurian rocks are
surrounded by a thin ring of Devonian strata (410 to 360 million
years ago). Devonian strata consits of limestones and
dolostones and a thick deposit of dark gray to black shale.
The limestones are mined in the Louisville area. They
sometimes contain abundant fossils, as at the Falls of the Ohio in
Louisville, Kentucky. Thick, dark gray to black shales are
the dominant Devonian strata in many areas of Kentucky. The
color of the shales comes from organic material trapped in the
rock. During the Late Devonian, muds were deposited beneath a
sea that covered most of the eastern United States. Organic
material in the muds was trapped. When the organic-rich
sediments were buried deeper beneath the surface, pressure and
temperature converted some of the organic material in the rock to
liquid form, called oil, and into gaseous form, as natural
gas. The largest gas field in Kentucky, with an estimated
reserve of many billions of cubic feet of gas, is the Big Sandy Gas
Field located in eastern Kentucky. The gas reservoir is in
Devonian shales buried deep beneath the surface. Much of the
oil found in Kentucky was originally in the Devonian shales, but
migrated to other rocks where it is found today.
Devonian Fossils
Devonian rocks are exposed at the surface in the Knobs Region,
which rings the Blue Grass Region. Devonian rocks are absent
in the Blue Grass Region, but occur below the surface in other
areas of Kentucky. During most of the Devonian, Kentucky was
covered by shallow tropical seas, although some very low lands may
have been emergent at times in central Kentucky. During the
later part of the Devonian, deep seas covered Kentucky, and the
water was poorly oxygenated at depth. Dark organic-rich muds
were deposited, producing the Devonian black shales in Kentucky,
which contain oil shales and are a potential source for a variety
of fossil fuels.
All the Devonian rocks found in Kentucky are marine and
consequently all the fossils are marine (sea-dwelling)
invertebrates and vertebrates. Common Devonian fossils found
in Kentucky include sponges (Porifera), corals (Cnidaria),
bryozoans, brachiopods, trilobites, snails (gastropods), clams
(pelecypods), squid-like animals (cephalopods), crinoids
(Echinoderms), and microscopic animals like ostracodes and
conodonts.
Probably the most common sponge fossils found in Kentucky are the
stromatoporoids, or stroms for short. Stroms are calcareous
sponges that form mounds 2 to 3 feet across on the sea floor.
Stroms still exist today in moderately deep water. Devonian
stroms can be seen at the Falls of the Ohio near Louisville.
Fossil bones of giant arthrodires, sharks, and other fish have been
found in the Devonian rocks in the Knobs Region of Kentucky.
Some giant arthrodires, with sharp cutting beaks, grew to more than
20 feet in length and fed on sharks.
The most commonly found plant fossils in the Devonian black shales
of Kentucky are silicified logs (called Callixylon) of the
seed-fern tree, Archaeopteris. Several silicified fossil logs
from these shales in Kentucky are on display at the Smithsonian
Institution in Washington, D.C. Rarely, foliage from these
and other plants is found in these Devonian shales.
The Silurian Period
Silurian Strata
On the geologic map of Kentucky, Ordovician rocks are surrounded by
a ring of Silurian strata (440 to 410 million years ago). The
area where these rocks crop out is known as the Knobs Region.
Silurian strata consists mostly of limestones and dolostones.
Where these rocks dip beneath the surface in the Big Sinking-Irvine
area of eastern Kentucky, they are very porous and form natural
reservoirs for oil. On the geologic map, one can see that the
Silurian rocks do not completely circle the Ordovician strata, but
rather pinch out to the south in Boyle, Casey, Lincoln, and
Montgomery Counties. Where the Silurian rocks are missing,
Devonian rocks lie directly on top of Ordovician rocks. This
is called an unconformity. An unconformity means that a large
segment of geologic time is missing from the rock record, just as
if someone had torn the pages out of a book.
Silurian Fossils
Silurian rocks are exposed at the surface in the Knobs Region,
which rings the Blue Grass Region. Silurian rocks are absent
in the Blue Grass, but occur below the surface in other parts of
Kentucky. During most of the Silurian Kentucky was covered by
shallow tropical seas. However, some very low lands may have
been emergent in central Kentucky at times. All Silurian
rocks found in Kentucky are marine and all the fossils are marine
(sea-dwelling) invertebrates. Common Silurian fossils in
Kentucky include corals (Cnidaria), bryozoans, brachiopods,
trilobites, snails (gastropods), clams (pelecypods), squid-like
animals (cephalopods), crinoids (Echinodermata), and microscopic
animals like ostracodes and conodonts.
DIRECTIONS
From the Kentucky Artisan Center at Berea (exit 77 off of I-75),
proceed east on KY 595. Turn left (east) onto Glades Road
until it intersects US 25 in Berea. Turn left (north) onto US
25 and proceed for 4.4 miles to Menelaus Road. Turn left onto
Menelaus Road and proceed 2.3 miles to the quarry. There is
room to pull off at the side of the road. Please exercise
care with young children. Traffic is light in the area but no
one will expect to find you parked beside the road.
DO NOT LOG AS A FIND UNTIL YOU HAVE A PICTURE READY TO POST.
To get credit for this EC, post a photo of you (I do not accept
pictures of just a hand) at the posted coordinates with the
Menelaus Quarry in the background (like my photo above) and please
answer the following questions.
- How tall is the cut? An estimate is fine.
- Measure the length of the exposed cut, along with the depth
into the hillside. What do you estimate as the volume of
limestone quarried here?
- Do you see any fossils in the exposed beds?
Do not wait for my reply to log your find. I will contact you
if there is a problem. Logs with no photo of the actual
EarthCacher/Geocacher (face must be included) logging the find or
failure to answer questions will result in a log deletion.
Exceptions will be considered if you contact me first (I realize
sometimes we forget our cameras or the batteries die). Logs
with no photos will be deleted without notice. I have used
sources available to me by using google search to get information
for this earth cache. I am by no means a geologist. I
use books, the Internet, and ask questions about geology just like
99.9 percent of the geocachers who create these great Earth
Caches.
Reference: Kentucky Geological Survey at the University of
Kentucky.
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