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7 Souvenirs of August

EarthCache

The Eddyville Dunes EarthCache

A cache by Hill Folk
Hidden : 9/30/2010
In Iowa, United States
Difficulty:
2 out of 5
Terrain:
2 out of 5

Size: Size: other (other)

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Geocache Description:

On the outskirts of Eddyville Iowa lies one of the most unique sand prairie remnants in the Midwest. An ecosystem that has disappeared from Iowa except for a few small areas around the state.
Thanks to lagrac for tweaking this Earth Cache and getting it published for us.

On a hike over the dunes you can often find rare plants and animals such as prickly pear cactus, pale green orchid, 6-lined racerunner lizards and ornate box turtles. The 55 acres of dry prairie communities are dotted with several open water wetlands and wet meadows.

The wind-blown sands of the Eddyville Dunes were deposited 12-15,000 years ago in a process very similar to the formation of Iowa's Loess Hills. The 1200 acres of sand deposits, up to 60 feet thick, are punctuated by closed depressions forming the numerous open water wetlands and wet meadows of the Eddyville Dunes.

During the last Ice Age, glaciers advanced into the middle of North America, grinding underlying rock into dust-like "glacial flour." As temperatures warmed, the glaciers retreated and vast amounts of meltwater and sediment flooded the Des Moines River Valley. The sediment was deposited on the flood plain, creating huge mud flats. When meltwaters receded, these mud flats were exposed. As they dried, the fine-grained silt was picked up by strong prevailing westerly winds. Huge dust clouds were moved and redeposited over broad areas. The heavier, coarser silt was deposited close to the Des Moines River flood plain, forming vast dune fields. The dune fields were eventually stabilized by grass. Due to the erosive nature of loess soil and its ability to stand in vertical columns when dry, the stabilized dunes were eroded into the corrugated, sharply-dissected bluffs we see today.

To receive credit for this EarthCache, please complete the following tasks. By doing so, hopefully you will learn a little about the geology of this special place.

1. N 41° 09.082 W 092° 37.012 Waypoint 1 will be the trailhead for the dunes. Take note of the elevation here. It will prove to be important later.

2. Observe the many sand deposits you'll find along the trail as you travel through the dunes. Feel the material in one of these mounds, describe its texture. What about the particle size?

3. N41 09.389 W092 37.209 Follow existing trails and move on to Waypoint 2. What is the elevation of Waypoint 2? What is the difference in elevation between Waypoint 1 and Waypoint 2?

4. N41 09.095 W092 37.278 At this Waypoint, note where the greatest sand deposits are. Using the compass on your GPS, please tell me which side of the trail has the largest deposits. Based on what you've learned so far about The Eddyville Dunes, is this what you've expected?

5. N41 09.190 W092 37.046 Although not necessary to log this EarthCache, pictures are fun and if you would like, please upload a picture at Waypoint 3.



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Inventory

There are no Trackables in this cache.

 

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60 Logged Visits

Found it 57     Write note 2     Publish Listing 1     

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Current Time:
Last Updated: on 7/27/2014 12:25:05 AM Pacific Daylight Time (7:25 AM GMT)
Rendered From:Unknown
Coordinates are in the WGS84 datum