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Colossal Cave

A cache by bennet Send Message to Owner Message this owner
Hidden : 4/4/2009
In Arizona, United States
2 out of 5
2 out of 5

Size: Size: not chosen (not chosen)

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Geocache Description:

Welcome to Colossal Cave! This is a wonderful spot just southeast of Tucson, Arizona, in the Rincon Mountains, where you can enter and explore a great cave containing a multitude of rooms, hallways, and geological formations and features.

Park at N32° 03.743' W110° 38.047' and then take the short walk down to the cave entrance at the posted coordinates. All access to the cave is by tour. The tours are held regularly throughout the day, as needed. You never have to wait longer than 30 minutes. The tour is about an hour in duration and one-half mile in distance. The temperature inside the cave is a constant and very pleasant 70°F.

Also, be aware that you will likely see bats. Seven species of bats live in the cave. They will not attack you and suck your blood. However, their smell will attack you. The odor of the guano is very strong, so be prepared for that.

Cave Formation:

When you visit the cave, you will see some excellent examples of crystalline formations, such as stalactites, stalagmites, flowstone, boxwork, and helictites.

Yet, this cave is now a dry cave. That means that, due to a lack of water, the formations are not growing right now. You could say that the cave, as far as geological change, is currently dormant.

But it used to be wet. Like the vast majority of cave systems, it was formed by water. The formation of the cave was actually from two different sources of water.

The first is the water that formed the passageways and open spaces. This occurred 10 to 15 million years ago. Heated water, laden with sulfuric acid, rose up from magma activity below. The acidic water reacted with the rock, dissolving it and, over time, cutting the voids that form the cave. At some point, the system cooled or was cut off and the water no longer rose into the cave system, and the voids were left.

Then, starting several hundred thousand years ago, a more common and traditional formation activity began. Water began seeping into the cave area from above, depositing crystals as the water flowed through the passageways. The buildup of the crystals eventually grew into the formations that exist throughout the cave - stalactites, stalagmites, and others.

The cave is perched on its hillside, well above the water table. It contains sparse soil and vegetation to hold moisture, and with many openings, large and small, that allow a high degree of air exchange with the arid climate outside. Therefore, under these conditions, it is dry.

The cave has been dry for at least 2000 years, and may have been dry for up to 10K years. Cross-section analysis has been performed on some of the stalactites here, and like tree rings, series of brown crust layers exist, which indicate past dry periods.


The first people known to explore this cave were the Hohokam Indians, back in 900 A.D. They used the cave for shelter and storage, and as a shrine. After the Hohokam occupation, the cave and no doubt other sites in Colossal Cave Mountain Park was used by the Sobaipuri people. This was a proto-historic people who occupied locations in southeastern Arizona from about 1440-1850 A.D. In more recent times, it was a hideout for bandits and train robbers. The facility has museums, books, and a library that details all the history regarding the cave and the surrounding area.

Colossal Cave Mountain Park is on the National Register of Historic Places. It received that honor in 1992.

Now, on to the requirements for completing this earthcache...


In order to claim this earthcache as a find, you must complete the following tasks.

Requirement #1 - Photo Of You And/Or Your G-Unit:
With your find log, you must upload a photo of yourself or your GPS unit at the cave entrance. Go to the posted coordinates and take the photo there. The photo should be taken with the cave entrance and thermometer in the background. Click here to see an example of the photo you need to post. Photos of faces are preferable, but just the g-unit is acceptable. Find logs without a photo will be deleted.

Requirement #2 - Determine Temperature Difference: Speaking of the thermometer, I want to know what the temperature difference is, at the time of your visit, between the outside air and the cave space. We know that the cave stays at a constant 70°F. And we also know that south Arizona gets beastly hot. So there is a thermometer right there at the entrance to the cave. What is the difference? Email the answer to me.

Requirement #3 - Find The Lowest Spot: During your tour, you will pass through the deepest part of the cave. You will need to identify that spot. How far below the surface (in feet) is this point, and where (which room or passageway) is it located? Email the answers to me.

Requirement #4 - Describe Old Baldy: Yes, I have one more for you. During your tour, you will see a stalagmite known as Old Baldy. What color is Old Baldy, and what does it consist of? Email the answer to me.

Remember Your Requirements:
Photo Of You Or Your G-unit,
Determine Temperature Difference,
Determine Location and Depth of Lowest Point, and
Describe Old Baldy.


To find your way to Colossal Cave Mountain Park from Tucson, take I-10 east to exit 279. Then turn north and follow Colossal Cave Road until it turns into Pistol Hill Road. Continue north on Pistol Hill Road for a few miles until you see the entrance for the park on the right. Signs are provided on this route. An alternate way is to take Old Spanish Trail southwest from Broadway or 22nd Street in Tucson.

The cave is just one feature of the park. There are great trails, camping and picnic areas, museums, and an equestrian area offering trail rides.

There is a park use fee of $5 per vehicle containing up to six people. The cave tour costs $8.50 for adults. The fees for children are less.

The park is open every day of the year. Summer hours (16 March through 15 September) are 8am to 5pm. Winter hours are 9am to 5pm.

More information is available at the Colossal Cave Mountain Park website. Click here to visit that website.

A Few Words About Logging This Earthcache:

All actions here should be common sense. Do not post answers in your on-line log. Logs that expose answers will be deleted. Also, logs not accompanied by email within a reasonable amount of time will be deleted per earthcache rules.

Like every other earthcache out there, there are simple tasks that need to be fulfilled. You need to perform the tasks to log the earthcache. They are very simple and basic, and they are designed so that anyone who is physically able to visit the area can do them. If you don't do the tasks, then you can't log the earthcache.

Occasionally, on one of my earthcaches, someone tries to enter a find log without even attempting the tasks. Among the excuses I have heard are "I didn't read the page, so I can't answer the questions." O_o Huh?! Pretty simple - if you don't even read the page and work the questions, since that is what defines the earthcache, then how can you say you did the earthcache?

Don't be shy. If you are unsure about an answer, that is okay. Give it your best shot. I promise I will give you an A for effort. It is the lack of effort that doesn't fly. And by all means, taking a photo is easy. Please get that done.

Now get out there and have fun. I hope you enjoy this great location!

Additional Hints (No hints available.)



179 Logged Visits

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Current Time:
Last Updated: on 8/6/2017 12:32:53 PM Pacific Daylight Time (7:32 PM GMT)
Rendered From:Unknown
Coordinates are in the WGS84 datum

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