Geological Exploration of Metro Cleveland (GEM-C)

The Geological Exploration of Metro Cleveland tour is a series of Earthcaches which help to illustrate some geology that is hidden within the urban downtown area of Cleveland. These urban earthcaches help to highlight a wide variety of geological topics that are hidden in plain sight - in fact thousands of people walk by these stones every day without so much as a second thought about their origins!

This tour does not need to be done in any particular order and each earthcache is a standalone lesson. As you wander through the streets of Cleveland take a moment to pause and reflect on the lessons you can learn in just a normal city block!

As with all earthcaches there is no container to find here, rather you must read through the description below and answer a few questions in order to log this cache as found. Please ensure that you send your answers to the CO via email or message in a timely fashion.

Soldiers' and Sailors' Monument

The monument you stand in front of was dedicated in 1894 and commemorates the American CiviI War. The column, topped with a statue of the Goddess of Freedom, defended by the Shield of Liberty, signifies the essence of the Nation for which Cuyahoga County veterans were willing to (and did) give their lives. If you're interested in more of the history of the monument and its significance, I highly recommend taking time to head into the interior and reading the plaques inside. 

This earthcache however focuses on how geologists use cross-bedding in sandstone to help determine how they were intially deposited millions of years ago! The sandstone used in this memorial is locally sourced Brea Sandstone (for more information on this specific type of sandstone, I recommend looking at GC234RG). Sandstone is created when small particles of pre-existing rocks are deposited in layers over time. These layers eventually pile up and the pressure of additional layers solidify the particles into a solid rock. How these particles are deposited are predominantly determined by examining the grain size and the layered striations of the rock.

There are several different ways by which small particles can be deposited before they become sandstone, some of the most common are:

• Fluvial depositions: These particles are depositied by moving water which slowly filter sedmintary particles to the bottom of a river, sea, or lake.
• Glacial depositions: These depositions occur as glaciers grind rocks into a fine powder which then are deposited as a glacier moves over an area.
• Aeolian deposition: Typically occuring in desert or beach environments, aeolian depositions occur as winds deposit small particles in dunes which then compact over time.

Each deposit type leave their marks on the resulting sandstone. Fluvial deposits result in sandstones with wavy cross-bedding as the moving water can leave hints of past currents and turbidities. Aeolian deposited sandstone typically show long sweeping layers characteristic of dune surfaces, and glacial depositions leave sandstones with poorly sorted grains with rough broken layers in their wake.

Logging Tasks

1. Examine the layering of the sandstone in the pedestal under the red rectangle (see photo below to find the correct location). Describe it as either rippled, sweeping, or broken.
2. Based on your answer to Question 1 what deposition method do you think caused the formation of the sandstone used in this memorial?
3. Take a photo of yourself (or if your shy, a personal item) in front of the memorial and include it with your log!

References:

• https://dam.assets.ohio.gov/image/upload/ohiodnr.gov/documents/geology/GB5_Hannibal_1992.pdf
• https://wiki.aapg.org/Sandstone_sedimentology_and_stratigraphy#:~:text=They%20sandstone%20beds%20range%20from,desert%20environments)%3B%20Shoreline%20(%20beaches%2C
• https://www.thoughtco.com/what-is-sandstone-1441016#:~:text=The%20layers%2C%20or%20bedding%2C%20in,indicate%20episodes%20of%20different%20climate.