As you are walking down the old mining road towards the pond,
just as you pass the softball field, you'll notice a steep
gully/ravine. It will stay on your right shoulder pretty much
all the way down to the pond.
Once at the pond, you are probably wondering who or what a Steno
is.
This pond was developed by the Randolph Mining Company for
double duty: Taking advantage of the natural ravine, Randolph
pumped water out of its deep underground mine, and deposited it in
the pond. There was a steam-powered pump station at the pond
which lifted water back up the hill to support various
mining/refining functions that required large amounts of
water. Today, there is an active creek coming down the
ravine into the east end of the pond, and it continues around the
northwest corner of the dam to run down and join Little Buffalo
Creek, just east of Old Mine Road.
We'll look at the pond through the eyes of Nicholas Steno
(1638-1686). Steno (he was born Niels Stenson in
Copenhagen, Denmark, but Latinized his name, in the scholars'
tradition of the time) received a medical degree, moved to
Florence, Italy, and found favor with the Grand Duke of
Tuscany. He was the beneficiary of the best education of
his era, and his was a bright, enquiring mind. In 1666,
two fishermen landed a huge shark, and the Duke ordered it's head
be sent to Steno for dissection and analysis. Big whup! What
does a shark's head have to do with geology and this pond? A
lot.
Steno noticed that the shark's teeth were precisely the shape,
form and size as objects called "tongue stones"; things that looked
just like shark's teeth, but they were found inside rocks.
There were all kinds of "theories" as to the nature of these
objects, but no one understood what they were. Steno
realized that they looked like shark teeth because they
were shark teeth. He reached the first
of three major conclusions: A fossil could be altered
chemically without changing its form. As a side note, in
Steno's time, a "fossil" could mean virtually anything dug from the
earth -- crystals, ores, true fossilized remains of ancient
creatures, and minerals.
He then was left with the problem of figuring out what process
allowed a shark tooth to become embedded in rock and
fossilized. He believed that all particles of rocks and
minerals had once been suspended in a fluid -- water -- and that
they slowly drifted down to the bottom of the lake, ocean, or pond.
This on-going process led to Steno's second major conclusion:
Such deposition will result in horizontal
layers. This is referred to as the Principle of
Original Horizontality, and is a fundamental tenet of
geology today (although it does not address metamorphic rock, it
can be applied to most igneous rocks. These latter are not
laid down out of suspension, but as ash, tuffs, lava, and other
volcanics forming horizontal layers after ejections.).
Understanding that the shark teeth were already hard when
deposited at the bottom of the water, he then reasoned that further
raining down of particles would bury them. After that
happened and more and more particles rained down, eventually those
particles would harden into stone. Therefore, there
would then be a hardened object in it's mostly original shape,
within another hardened object -- a layer of rock. In
his most important insight, he realized that layers of rocks are
arranged in a time sequence, with the oldest on the bottom and the
youngest on top. Later processes, such as an earthquake or
rising up of mountains, could change the order, but the original
rock layers (strata) were laid down with the oldest on the bottom
and the youngest on top. This is known as the
Law of Superposition, and forms the basis for all
evaluation of the relative ages of layers of rock that make up the
earth's surface.
Steno's conclusions may seem obvious to us today, but 340 years
ago most people believed the landscape they saw was left behind as
the Biblical Great Flood evaporated. While he probably
understood that the depositional processes he figured out must take
place over time -- a very long period of time -- he did not
publicly speculate about how long such processes might
be. Steno's contribution was not just the "laws" he
described; his method of scientific observation and thought was a
model for scientists to come. Indeed, 18 years later,
Sir Isaac Newton was to publish his Principia, and a key
tenet of that monumental work was that nature follows a set of
laws, and that they can be observed and understood by humans.
Obviously, this little pond is too small to eventually form a
large body of distinct strata, as the dam will eventually give way
or be undermined in the northwest, but the processes Steno
identified are observable here. At the edge you can see
leaves and other things that will eventually break down and settle
onto the bottom. The cloudy nature of the water, especially
just after rains, indicates that clay, mud, sand and other grains
of future rock are present and will be settling out. If
a small fish, bird, or some lizard should perish and float to the
bottom, it's hard parts may be covered up and eventually become an
object of interest for a non-human paleontologist far in the
distant future.
All professional geologists, geology students, and amateur
geologists like me (and I hope you) merely stand on the shoulders
of the giants who went before us, and Nickolas Steno was certainly
a Giant.
Logging
Questions:
Send me an e-mail – not part of your log –
responding to the following:
1. Make the first line of the e-mail “GCxxxxx, Steno
and the Pond”
2. How many people were in your party?
3. Assuming the concrete dam never breaks and the
stream is unsuccessful in cutting into the northwest bank to
undermine the dam, in the span of a human lifetime, what do you
suppose will happen to the pond [Hint: All ponds have a "life
cycle."]
4. Instead of a quiet country pond, imagine that you were
standing (or floating in a boat) in the Gulf of Mexico, at the
furthermost reaches of the Mississippi River delta. Would
Steno's observations about horizontality and superposition apply?
Why or why not?
5. Find a small twig and throw it 10-15 feet from shore.
a. After watching it for 2-3 minutes, tell me
in what direction is it floating (if any)?
b. How fast is it floating in that
direction?
c. Is there a stiff breeze helping to move the
twig?
d. What do your observations in a. and b. tell
you about the environment for sediment build up in this part of the
pond?
5. Optional: Please post a picture of you and your party with
the pond in the background.
Note: For other EarthCaches in the Gold Hill mining district, go
here.
Platinum EarthCache Master