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Dillon Pass Erosion

A cache by PurplePaws Send Message to Owner Message this owner
Hidden : 8/25/2008
1 out of 5
2 out of 5

Size: Size: not chosen (not chosen)

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Geocache Description:

Safety First!
At the posted coordinates is a parking lot on the southeast side of the Badlands Loop Road. Please park here as this spot is the best for road safety and visibility from oncoming traffic. Parking along the roadside is dangerous due to poor traffic visibility, so please use the parking area and make the short hike across the road. Always be safe and look both ways for traffic when crossing the road. In fact, you’ll need to take a pic of you and your GPS at the interpretive sign in the parking lot anyway, so you may as well park there…

Hike to the following coordinates: N43 50.733 W102 11.719. Again, please be mindful of traffic. These coordinates will take you to a less-steep path to the marker, rather than hiking straight to it which would involve steep climbs.

The final coordinates for the actual marker location are: N43 50.668 W102 11.726. You will see two other markers in the area. At the time of this publication, one of the markers was destroyed. THESE ARE NOT THE MARKERS YOU WANT. Go to coordinates I just gave you and use that single marker for your data gathering.

This is the marker you are seeking.

The Geology
During our paleontological surveys of the park, I noticed several benchmarks that have the dirt around them eroding away, leaving behind only the concrete and benchmark. When benchmarks are originally set, they are often done so in concrete. A hole is dug in the ground and the benchmark set. Concrete is then poured in around the benchmark post, leaving it flush with the surface of the ground. What you will be looking for is one of these benchmarks, partially eroded out of the ground. The benchmark has a date on it. Make note of that date as you will need it to calculate the rate of erosion. Now, measure the distance between the part of the concrete that was originally flush with the ground, and the current distance to the ground directly under it.

Logging the EarthCache
In order to log this cache, you must do three simple things:

1) Post a picture (with your logged find) of you and your GPS at the interpretive sign in the parking lot. (Please don’t post any pics of the benchmark- the interpretive sign in the background will be fine.) AND,

2) Send a message to me (do NOT post in your log), explaining how many inches (or if you prefer- centimeters or millimeters) per year the surface at this location has eroded away. Assume the marker was placed on January 1 of the year indicated on the marker. If you do not have a tape measure with you, please use something else like a length of string, wire, road atlas, sheet of paper, walking stick, dog leash, etc. You’re a cacher- be inventive! (I used a string and marked it, then measured the distance between my marks when I got back home). I suggest you take multiple measurements at different points around the circumference of the concrete and average them to one value. Provide your value to two decimal places- for example: 8.76 inches/year, AND

3) Answer- Do you think the rate of erosion is the same for each year between the date the benchmark was set and present day? Why or why not?

Please also include the number of people in your party and please include the cache title "Dillon Pass Erosion" at the beginning of your message.

Geology is a fun and interesting subject for me, and I enjoy sharing it with others. I hope you enjoyed this opportunity to learn more about this site and will better appreciate the geologic processes that made it possible. As always, please obey all park rules, take only pictures and memories, and leave only footprints. Practice CITO too!

I’d like to thank Badlands National Park employees Judy Olson, Director of Resource Education for permission to publish this EarthCache, and Julie Johndreau, Resource Education Specialist for review, discussion, and testing.

Photos by PurplePaws.

Geological Society of America

Additional Hints (Decrypt)

Ybtf jvgubhg gur cebcre cubgb naq/be ybtf juvpu unir abg frag ernfbanoyr nafjref jvyy or qryrgrq jvgubhg abgvpr.

Decryption Key


(letter above equals below, and vice versa)



  • Dillon Pass MarkerLook for the last two letters of the date in the area which has been deleted in this photo.

401 Logged Visits

Found it 389     Didn't find it 4     Write note 6     Enable Listing 1     Publish Listing 1     

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Current Time:
Last Updated: on 12/31/2017 2:00:15 PM (UTC-08:00) Pacific Time (US & Canada) (10:00 PM GMT)
Rendered From:Unknown
Coordinates are in the WGS84 datum

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