Standing Rocks
Standing rocks are ancient remnants left by millions of years of exposure to the forces of erosion. These masses of rock stand alone like pillars, detached from the main body of bedrock that can be found in nearby cliffs or hillsides.
Salt Shake Rock is one of only a few good examples of standing rocks in Indiana. The nearest (and definitely more famous) example is Jug Rock near Shoals in Martin County. Another example can be found at Pompey’s Pillar near Napoleon in Ripley County.
Salt Shake Rock stands on its own, several yards away from the adjacent ridgeline. You can follow this ridgeline all the way back out to Interstate 64, where a tall cliff stands at the road cut for the interstate. Geologists have identified the rocks in this ridgeline as being from the Carboniferous or “Mississippian” Period (about 350-290 million years ago). These rocks made up of limestones, shales, and sandstones were formed from the buried remains of plants and animals that lived in the shallow waters of the inland sea that covered this area millions of years ago.
Standing rocks are shaped by the forces of erosion, including frost, plant roots, and running water. Each of these forces acts on the joints in the rock, slowly forcing them apart over millions of years.
Close examination of Salt Shake Rock reveals evidence of each of these forces. When it rains, you can see the paths that the water takes through the joints in the rock. The outer surfaces of the rock feature honeycomb patterns typical of frost shattering. You can also see the work of tree roots and other plants on and around Salt Shake Rock.
Salt Shake Rock will continue to bear the brunt of erosional forces. Eventually, it will succumb to these forces and topple over. Pedestal Rock near Shoals in Martin County suffered this fate several years ago, when a severe storm hit the area and toppled it. All that’s left of Pedestal Rock is a pile of shattered sandstone slabs. Hopefully Salt Shake Rock will stand for thousands of years to come!
To Log This EarthCache
OPTIONAL: Take a photo of yourself with your GPSr with Salt Shake Rock in the background. While not required, we always enjoy seeing photos of our fellow cachers!
To demonstrate the educational value of your visit, please email me the answers to the following questions: (click on the El Pollo Loco Gang link at the top of the cache page to reach our profile, where you will see a link to Send message)
1. Estimate the height of Salt Shake Rock. Also, estimate its width at its widest and narrowest points.
2. How does Salt Shake Rock compare to the adjacent bedrock in the extended ridgeline? Give some examples of similarities between the two.
3. Look for evidence of the ongoing erosion of Salt Shake Rock. Can you spot an area where erosion is chipping away at Salt Shake Rock? (Hint: Look at the base on the south side!) Describe what you see and predict what effect this erosion will eventually have on Salt Shake Rock.
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