Check Out The Pan, Man! EarthCache
-
Difficulty:
-
-
Terrain:
-
Size: 
(other)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
For this earthcache, you are going to learn about solution
pans.
Solution pans are small scale geological solution features.
"Solution", in geology-speak, means that the feature was formed by
water and acids dissolving the rock. Pans are typically small,
relatively speaking. They are shallow and panlike, and range in
diameter from just a few feet to dozens of feet. Pans have an
impervious base and hold water.
When dissolution results in larger features, other terms are used
for those features, such as pits, cavities, hollows, and even
sinkholes, or dolines. A large amount of dissolution in a
particular area can ultimately evolve to a subterranean drainage
system of drips, trickles, and streams. Under these coniditions,
cavities and voids continue to enlarge and rock is undermined. Some
blocks of rock are so undermined that they collapse to form
isolated holes, coalesced holes, and long sinuous troughs or
valleys conforming to underground streams. The resulting landscape
is called karst topography.
Solution features like pans are frequently found in the desert,
however the features are not formed under arid conditions. Their
formation requires the presence of slightly acidic water (rainwater
and snow melt usually with carbonic acid) to dissolve a slightly
soluble material, usually limestone.
There are many factors that affect the rate of dissolution. These
include the composition of the rock, the temperature, and the
acidity of the water. Other factors include the type of bedding
present, the structure of the rock formations, the extent of
fracturing, etc.
In desert landscapes, solution features usually are relicts from an
earlier time and a different climate. Wherever calcium carbonate is
part of the rock, such as limestone, limy conglomerate, etc., some
solution can take place where water is episodically present.
Dolomitic limestone, which contains magnesium, is the least soluble
of the rocks. Solution features can also be found in gypsum.
Please be careful. Solution pans hold rain water and snow melt.
Therefore, they provide a critical source of water for inhabitants
of the desert. Whenever you are in the proximity of solution
features, be very careful to not contaminate or pollute the water
contained inside.
How To Complete This Earthcache:
Bring a tape measure!
The posted coordinates lead you to a spot in the Santa Catalina
mountains, where you will find good examples of solution pans. To
get there, you need to take the Catalina Highway, which is a paved
mountain road that runs north out of Tucson. There is a small fee
($5 or so) for recreational use. You completing an earthcache is
recreational use.
At mile 14, you will reach the Windy Point scenic overlook. Plenty
of parking is available. After you park, start walking toward the
posted coordinates. You will find a trail that ultimately takes you
alongside the formations.
When you reach the coordinates, you will find many examples of well
formed solution pans in the rock.
Click here and
here to see examples of what you will see.
The elevation here is around 6500 feet I believe. The scenery is
outstanding.
Have Fun! Post A Photo Of Yourself.
Sometimes, things become misguided. Earthcaches and geocaches are
supposed to be all about the fun and the experience of the
location, and about performing simple tasks and getting into the
spirit of the earthcache. Try to embrace the original spirit of
this earthcache and use one of the most powerful tools available to
the field scientist - the camera. Try to take a photo of yourself
with one of the solution pans appearing in the background, and post
it with your find log. A photo used to be listed as a requirement
for this earthcache (prior to 15 May 2011), and as the past logs
show, it was fully supported without any protest or controversy. It
is a simple task that has always been completely reasonable, with
everyone being supportive of it. However today, a photo is not
required, due to the poor administrative practice of levying
control over a small benign detail that affects nothing outside of
the individual earthcache.
For this earthcache, a photo is simply requested, and is in line
with the spirit of this earthcache.
Click here to see a photo example. I don't care about your GPSr
being in the picture.
LOGGING
REQUIREMENTS:
In order to claim this earthcache as a find, you must complete the
following tasks.
Requirement #1 - Make Some
Measurements: At the coordinates, you will find a number
of well formed solution pans. There are a couple of very nicely
formed pans located close to the edge (toward the dropoff).
Click here to see one of the pans that I am talking about. With
your tape measure, measure the width of one of those solution pans
at its widest point. Hint: your measurement should be greater than
than 24 inches and less than 144 inches. 
Requirement #2 - Identify The Type Of Rock
And The Reactive Component: Inspect the rock here and
identify it. Is it limestone? Is it sandstone? Is it conglomerate?
One of the components of the rock here is reactive to acidic water,
supporting the process of dissolution. What is it? Dolomite?
Formaldehyde? Magnesium? Calcium carbonate? Gypsum? Calcium
sulphate dihydrate? Answering these questions will require you to
closely inspect the rock, and perhaps perform a little
research.
Requirement #3 - Email: Send an
email to me that documents your findings. The email should include
your measurement, along with the identification of the type of rock
and the reactive component of the rock. Do not post your answers in
your on-line log.
Logs not accompanied by email within a reasonable amount of time
will be deleted per earthcache rules. Please be careful to get done
what you need to get done.
Remember Your Requirements:
Make Measurements,
Identify Type Of Rock And Reactive Component, and
Send Your Answers In Email.
And If You Will, Please Post A Photo With
Your Log.
I hope you have fun.
Additional Hints
(No hints available.)