Experience this EarthCache
Please note:The Ault Park pavilion is regularly rented out for events. This rental area includes the EarthCache feature. Please be respectful and do not approach the site if there is an event going on. Be especially mindful on Fridays, Saturdays and Sundays because this is a very popular wedding spot! You can even call ahead at 513-357-2604 to ensure that your caching will not overlap with an event!
Welcome to beautiful Ault Park! Here you will learn a bit about glaciers and what they might leave behind.
Before you is a large pick granite boulder with a plaque on it. Feel free to read the plaque and learn some history, but what a geologist might be interested in is the boulder itself. You might notice that it is granite, a course-grained igneous rock that formed from volcanism. It is also pink (meaning there is lots of iron in the minerals). This does not look at all like the bedrock around Cincinnati, which is the fossil-rich greyish limestone deposited under the sea.
This is called an “erratic”. The term “erratic” is used because the rock type does not match that of the local bedrock (i.e. granite ≠ limestone). In this case, the boulder was brought here as a memorial stone, but this rock actually originated from some kind of glacial deposit, based on its roundness and smoothness. In areas north and west of here, the great Laurentide Ice Sheet dropped very similar rocks down as it advanced and retreated during the last ice age. This rock may not have been dropped in this very spot, but it is a great example of a glacial erratic, and represents the glacial activity in Cincinnati for the purposes of this GeoTour.
Northern parts of Cincinnati were glaciated during the last ice age, but existing evidence is scarce. As you see all around you, the area is carved by river systems - ancient rivers, glacier meltwater rivers, and modern rivers. Even further north is farmland, which means boulders were removed a long time ago for farming purposes.
If you were to explore the mountainsides and valleys of somewhere like Maine, you would find thousands and thousands of boulders just like this, except they were dropped by the glacier and have remained where they were dropped for many years! This is a common glacial feature in many places.
* Source research and text by LtStabos.
Once you log this Earthcache as "FOUND" please message us the answer to the following question within 1 hour.
- How tall is this boulder? How wide is this boulder?
- What markings do you see on the backside of the boulder? How do you think these were formed?
For your GeoTrail Passport you will need to collect the following answer.
- Read the plaque and finish this excerpt: “This park was the _______”.
To access the Earthcaching 101 GeoTour Digitial Passport: CLICK HERE.
EarthCaching 101 GeoTour Locations:
- ECGT A Walk Through Time (GC7P5RE)
- ECGT Rocks of Fountain Square (GC7P5RG)
- ECGT Ohio River Flood Gauge (GC7P5RJ)
- ECGT Very Old Logs (GC7P5RM)
- ECGT Mount Adams Landslide Hazard (GC7P5RN)
- ECGT Cincinnati River Valleys (GC7P5RQ)
- ECGT "Glacial Erratic" (GC7P5RT)
- ECGT Pervious Pavement (GC7P5RW)
- ECGT Forest Avenue Wetland (GC7P5RZ)
- ECGT Cincinnati Fossils and Stratigraphy (GC7P5T1)