Eddies and Erratics EarthCache
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This is an easy Earthcache so families can experience this type of cache together. Where the goal of a traditional cache may be to get a smiley, the goals of an EC are knowledge and experience. These have always been a favorite cache type of mine and I think your family will enjoy the opportunity to visit this area and learn about the forces that shaped our state's geology. I suggest you bring along your watch and a method to measure how far you've walked when you visit this cache.
Congratulations to dsuperfan23 for the FTF!!
If you were to explore our state by driving from the southern border along the Ohio River to the northern border shared with Michigan you would observe some very different landscapes. The first third of your journey would be marked by rolling hills and limestone outcroppings. If you stopped to wade in the creeks that run through the deep ravines you might find fossils and other odd stones. As you continued your drive north you would reach a line running approximately from Terre Haute to Richmond where the land would begin to flatten out. Continuing north toward Mishawaka the terrain would become almost table top flat. The road would weave between many small and medium sized lakes and occasionally a large bolder might be spotted in the middle of a field. At the end of your trip you might pause to wonder what, in the relatively short distance of 270 miles, had caused such large differences in the landscape. The answer is quite simple, ice.
Glacial ice extended and retreated several times in the Midwest between 2,588,000 to 11,700 years ago during the Pleistocene epoch, or the Great Ice Age. Around 16,000 years ago glaciers covered most of what would become Indiana. Over the course of hundreds of years, the glaciers slowly moved south at the rate of a foot a day but never extended past the central region of the state, ending 117 miles north of this cache. Once the glaciers melted the dirt, rocks and sand - or glacial till - that were picked up by the ice were all that was left behind. Any hills or valleys created by previous ice ages were filled with this till and left the land flat. Today this central area is known as Tipton Plain Till. In the northern part of the state, where glaciers retreated more quickly, moraines - or glacial till ridges - were left, but was still left relatively level.
Since the ice never reached southern Indiana much of the evidence pertaining to the ice age in this area consists of features caused by the large amounts of glacial melt water. The glacier water created the karst topography by eroding and shaping the existing sedimentary bedrock deposited eons ago. It deposited various sized granite and basalt stones which had been trapped in the ice throughout the landscape. These stones are called erratics because they differ from the area's bedrock. Another piece of evidence sometimes seen in the area are glacial striations or "scratches" cut into bedrock as the water pushed harder granite erratics across the softer limestone or sandstone bedrock.
One other interesting geologic feature created as the glaciers retreated northward are circular depressions in the bedrock, commonly found in creeks or ravines with rock bottoms, called potholes. As the glacial melt water flowed over the area it carried with it various sized erratics which were sometimes caught in the eddy currents of the glacial run off where the abrasive, churning action ground a bowl shaped depression into the bedrock. One famous Hoosier example of a pothole is the Punch Bowl located on Trail #3 in Turkey Run State Park. While much less dramatic than its more famous cousin the pothole before you is a good example showing the result when the forces of water, stone and time combine.
Completing the requirements to log this cache will give you a feeling for the amount of that final factor that is involved in creating geologic changes and sharpen your observation skills. To complete the requirements you must do the following:
1.) Using your GPS's odometer, a pedometer or counting you strides, measure the distance WHILE WALKING ON THE BORDER TRAIL from the sign at the trailhead to the EC.
2.) Record the amount of time it took you to walk from the sign to the EC.
After you have done this email me the following information;
1.) The distance from the sign to the EC and the amount of time it took you to walk it.
2.) Using the information from the narrative calculate the number of days it would take a glacier to cover that same distance.
3.) Very near the pothole is another piece of ice age evidence that was mentioned in the narrative. Tell me what that evidence is.
You might also bring along a CITO bag and help maintain the natural beauty, though this is not a requirement. Post a photo with your log if you would like.
Additional Hints
(Decrypt)
1)Gurer ner 365 qnlf va n lrne
2)Gurer ner 5,280 srrg va n zvyr
3)Rznvy zr sbe nabgure uvag vs lbh trg fghpx