The coordinates will take you to a large outcrop of Manhattan bedrock in which I "discovered" this Glacial Pothole. I was climbing all over this outcrop, actually looking for something else (Randall grid benchmarks), when I found this hole and immediately got excited. I believe it is a known geological feature of the park and maybe one day I will get to the Central Park Library to confirm this. The pothole is easily accessed from the nearby paved path. Do not climb on the outcropping rock. Please watch all children at this site as they are always tempted by a climbing challenge.
Glacial Potholes are formed when bits of detrital sedimentary material, such as sand, pebbles, stones and even large boulders, are driven by fast moving water over time to scour out a hole in bedrock. They form in River beds, in the bottom of Water Falls and under Glaciers (Subglacier Rivers and Moulins). Their presence indicates many things about past environmental conditions.
You must visit the site in order to make some simple observations and take a few measurements in order to answer the following questions. Some research may be required- but not too much. But I warn you, you will be required to think.
You will email me your answers when you log this EarthCache, but post directly to the page your photos. (do not include any photos that will give away an answer). You will need to bring the following in order to answer the questions 1)a tape measure 2) work gloves 3) pen and paper 4) map showing coordinates of this Earthcache or GPS and 5) a camera.
1) 2 measurements; how deep is this pothole and what is the diameter of the opening.
2) Hands on; feel the inside walls of this pothole and the very bottom. How would you describe the texture of the inner walls and the shape of the bottom? Is the inner wall regular in shape (think; cylinder) or are there any fluctuations? If you detect any, what in your opinion could cause this?
3) Observations; what is the apparent color of the rock outcrop that this hole is in? What is the color of the inner walls of the pothole. Are they different. If they are, why?
4) Close to the Pothole and embedded in the outcrop is a man made artifact. What is it? Can you see now why I think this is a known geological feature of the Park?
5) Observation: The edge of the hole closest to you is lower then the edge furthest away. Why? Can you suggest a series of events that would account for the appearance of the outcropping rock and the hole. Here's a possible hint; This rock outcrop is a "Roche Moutonnee".
POST YOUR ANSWERS AND YOUR PHOTO BEFORE LOGGING. REQUIREMENTS AND DISQUALIFICATIONS FOR LOGGING THIS EARTHCACHE; 1) No group or team answers. If you want your own smiley, then you must submit your own answers. Any mention even of "team" or "group" or similar word in your log will be result in a deletion. 2)All parts of all questions must be answered. If you do not fully answer, then your log will be deleted. 3)You must post a photo of yourself at the site. Your photograph(s) may NOT include any information that gives away answers. 4) Do not expect that I will respond to any emails about deleted logs that flagrantly failed to conform to the logging requirements. To reflect the changes in logging requirements for this Earthcache I have changed the difficultly rating from a 2 to a 3. The Terrain is still only a two since this geological feature is only 10-15 feet off of a paved path.
This EarthCache is dedicated to the memory of my Grandfather, born 110 years ago on August 1, 1904, who is still inspiring me today.