Fingernails On Blackboard EarthCache
Hidden : 8/25/2008
Difficulty:
2 out of 5
Terrain:
2 out of 5

Size: Size: not chosen (not chosen)

Join now to view geocache location details. It's free!

Watch

How Geocaching Works
Looking for a different adventure?

Please note Use of geocaching.com services is subject to the terms and conditions in our disclaimer.

Geocache Description:


Bring a compass! You are going to track a glacier, my friend! Okay, maybe only a few feet, but it is still tracking a glacier...

Welcome to Oakes Quarry Park. Old abandoned quarries are fun places in which to play and learn. There is a lot of rock here.




The park is open daily, from dawn to dusk. While at the park, please respect the rules and guidelines that are posted on several signs, and follow the "Leave No Trace" outdoor ethic. Please stay on-trail at all times.


During the Pleistocene Epoch (the Ice Age), many areas of Ohio were covered by glacial ice, including the Dayton area. During the last advance of the glaciers, ice estimated at one thousand feet thick was present here. That was 24000 to 18000 years ago, and it was the Wisconsinan glacier. Igneous, metamorphic, and sedimentary rock of all sizes and shapes were caught up in the ice and left behind as the ice melted. In this quarry, there exists different types of evidence of the glacial activity, which ended about 14000 years ago. There are erratics (rocks moved and left behind by the glacier), polished rocks, and glacial striations.

Chunks of rock that were trapped in the ice at the base of the glacier acted as cutting tools, scraping off the bedrock and polishing its surface smooth. These rocks also made grooves and scratches in the underlying rock. These grooves are called glacial striations. They are the everlasting fingerprint that a glacier leaves behind when it retreats.

Think of it like someone pulling their fingernails across a blackboard. That annoying thing that people sometimes do, like that dude in Jaws. The limestone is the blackboard. The rocks are the fingernails, and massive moving ice is the fingers, hand, and arm. Except the glacier did not make that annoying sound. And real fingernails do not really make grooves in a blackboard. Okay, so it is not the same at all really. But it is a fun analogy to try for anyway.

Anyway, recovering from that tangent... At the location pinpointed by the posted coordinates, you will see very good examples of glacial striations. At the coordinates, you will be standing on lots of exposed limestone bedrock, and what is considered to be glacial pavement. At various spots in the exposed bedrock, you can see the grooves caused by the glacier. You can run your fingers over them and feel the indentations.

Do not confuse the glacial striations with the lighter-colored scratches that are present here and there. Those scratches were produced by quarry machinery. Quarry machinery happened a few years after the glacier. Just a few.

Glacial striations are present at other locations in Ohio. However, this is one of the few known locations in the state where these features are protected and are accessible to the public.


LOGGING REQUIREMENTS:

According to Earthcache rules, in order to claim the find, you must perform an educational task. So, I ask that you do the following:

Requirement 1: Determine Direction Of Glacial Movement

At the posted coordinates, you will find a number of examples of glacial striations. Click here to see an example. You will notice that the striations typically appear in a group of at least several grooves, and the grooves are parallel to each other (i.e., they all run in the same direction). What does that mean? Think about it. That has to be the direction of glacial movement, right?
Yes. Glacial striations can be used to determine the direction of the movement of the glacier.
Here is where your compass comes in. Using your compass, determine the direction that the striations run relative to true north. I would like an answer accurate to a boxed compass (i.e., E, EbN, ENE, NEbE, NE, NEbN, etc.). Your answer should be relative to true north. The current magnetic declination for the Dayton area is about 8°W.
Note: At this quarry, two different directions of striations can be seen, recording two different glacial events. You can work with either.

But that's not all. Obviously, there are two directions that are indicated by a "line" like a striation. It is either that way, or the opposite way (180° the other way). For example, a line that runs ESE also runs WNW. So. Which direction did the glacier move with your lines? How do you know that it did not move the opposite direction?

Requirement 2: Compare The Glaciers

At N39° 48.829 W083° 59.010, there is an interpretative sign that provides lots of interesting information. It includes a fantastic map of the glacier history of Ohio. That is a cool map. According to that map, there was a glacier that preceded the Wisconsinan, and existed 130,000 to 300,000 years ago. What is the name of that glacier? And of those two glaciers, which one extended further south into the state of Ohio? (Hint: one of them reached at least as far south as what is now the Ohio River).

Requirement 3: Email

Send me an email through gc.com that provides your answers. The email should include your answers for Requirement 1 and Requirement 2.

Requirement 4: Photo

With your find log, post a photo of yourself that clearly shows that you visited the location. Posing by the interpretative sign is good. Trying to include the striations with your head shot may not work if you want the striations to be visible, because they may be hard to see at a distance. I do not care about your GPSr appearing in the photo.



Post your photos with your online log, and email me with your answers. Logs not accompanied by email and photo within a reasonable amount of time will be deleted per earthcache rules. I don't want to have to do that!

References:
Ohio Geology, Spring 1998. Ohio DNR, Division of Geological Survey. Available online at
http://www.dnr.state.oh.us/Portals/10/pdf/newsletter/Spring98.pdf

Thanks to Pete Bales and the City Of Fairborn for allowing this earthcache! The City has really done a great job of converting this quarry into a great park, recognizing the geological features, and working to protect them. Fairborn rocks!

Click here for the website for the City of Fairborn.

Additional Hints (No hints available.)



Advertising with Us