Pikes [Potential] Leak
In Iowa, United States
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This EarthCache will take you to the beautiful Pikes Peak State Park in Clayton County, Iowa. The area contains a rich geologic history and remarkable beauty. You will observe a site of sedimentary bedrock and surrounding land that has been affected by, yet has also resisted, the natural erosive force of water.
Pikes Peak is considered one of Iowa’s greatest natural treasures. This state park is located within Clayton County and is perched high on the bluffs overlooking the Mississippi River. The area is known for its remarkable natural beauty, rich history, and significant geologic exposures.
Found within the Paleozoic Plateau landform region, Pikes Peak contains a significant amount of exposed sedimentary bedrock. Millions of years ago, the state of Iowa was covered by water and likely resembled the marine environments of the shallow areas of today’s oceans. As time passed (between 490 and 505 million years ago), numerous layers of calcium carbonate (i.e., limestone) deposits developed in these tropical sea regions forming the beginnings of Iowa’s sedimentary bedrock layers. At Pikes Peak, this limestone had later been chemically replaced by dolomite, another significant type of bedrock prominent in the northeast Iowa region, composed of magnesium calcium carbonate. Other types of rock layers include sandstone and shale. (Field experts can distinguish these four layers based on color, consistency, and chemical composition.) Throughout history, some of the land overlying the sedimentary rock has been naturally eroded by water, exposing the landscape’s bedrock layers, which have also been eroded and weathered by the slight acidity of rainwater. This erosion has consequently produced the beautiful bluffs and valleys highly visible at Pikes Peak.
This Earthcache will lead you to a picturesque yet geologically significant structure in the heart of this state park. The water that temporarily streams over this site has largely eroded the landscape, exposing the dolomite bedrock as well as the land below the structure, creating a cavern of the water’s former path through a process known as sloughing. Sloughing is the mass movement of soil by a particular force (water in this case) down a bank and into a nearby channel (the Mississippi River). The sloughing here has exposed the layers of the sedimentary bedrock that were deposited many years ago. Unique here are two prominent, erosive-resistant dolomite ledges that have remained over time and have created this site into a small, waterfall-like scene when “the time is right.” Do note that this is not an actual waterfall, however; only when enough water is available will this “leak” be present.
To log this Earthcache, complete the following requirements:
- At this waypoint, turn directly around so you are now facing away from the site. Based on the information explained above, explain why the land you are viewing now towers above you as compared to the existing land behind you.
- Was water flow present during your visit to this site? Based on the recent weather and climate surrounding your visit date, explain why you believe it was or was not present.
(No hints available.)
Last Updated: on 09/10/2016 12:38:41 Pacific Daylight Time (19:38 GMT)
Coordinates are in the WGS84 datum