In the Midwestern United States region, visitors and residents alike seek attractions and things to do such as going to amusement parks, sporting events, or discovering big cities like Chicago and Milwaukee. And then there are some visitors and residents who get their thrills from finding connectedness with nature and discovering the rich history of places like Starved Rock State Park, located in the north central part of Illinois. This glorious rock formation, located less than 100 miles from Chicago, is made up of St. Peter Sandstone, and is famously known as Starved Rock State Park. A few months ago, my family visited this beautiful park and learned the vast history on a guided trolley tour. We learned on the tour that his massive state park is known for its large, beautiful canyons that were formed by melted glacial waters millions of years ago. St. Peter Sandstone is a sedimentary rock that dates back to the Ordovician age (approximately 450 million years ago). St. Peter Sandstone is a sedimentary rock that was formed in oceans and other marine environments. It just so happens that during the Ordovician time period, the state of Illinois was actually located below the Earth’s equator (Gale, D. N., 1970). The specific type of sandstone (St. Peter) is composed of crystalline silica, a mineral found in the crust of the Earth otherwise known as quartz. The spectacular rock formation and waterfalls along with 18 miles of hiking trails are home to thousands of visitors each year at Starved Rock State Park.
Around 600,000 years ago, during the Wisconsinan Glacial age, the land that is now called Starved rock was frozen under almost 5,000 feet of glacial ice. When a glacier is moving forward and retreating, or in other words melting, it collects rocks that move along with it. When the glacier stops moving, the rocks that is has collected drift into a pile called till. Because ice cannot sort sediment that it carries, deposits of till remain unsorted (Tarbuck et al., 2019). When a glacier stops moving and remains stagnant (terminal), the piles of drifts continue to accumulate into even larger piles called end moraines. End moraines form when ice around the glacier continuously dumps the piles of till in the same area as the stagnant glacier above over and over again. Eventually, over time, the glacier melts, revealing the massive deposits of sediment.
Approximately 14,000 to 17,000 years ago, major flooding resulting from melting glaciers called the Kankakee Torrent in the Midwest swept through central Illinois. The constant flooding slowly but surely eroded away at the landscape, revealing the glorious sandstone formed from stone deposits from a previously melted glaciers end moraine. Sandstone is “an abundant, durable sedimentary rock primarily composed of sand-sized grains” (Tarbuck et al., 2019). Formation of sandstone takes place in lakes, oceans and rivers. Sandstone is formed in two basic stages: layers upon layers of sand build up as sediment, transported by either water or air. In the case of Starved Rock, the layers were built up from glacial waters. In stage 2 of the formation of sandstone, the sediment is tightly compacted and cemented together. Sandstone is the second most abundant sedimentary rock, accounting for approximately 20 percent of the entire group, making it another attractor among sedimentary rock types (Tarbuck et al., 2019).
The type of sandstone located at Starved Rock Park and be narrowed down to St. Peter Sandstone. St Peter sandstone was name by Arkansas’ first geologist that stumbled upon this specific type of rock exposed along the St Peter River in Minnesota. St Peter sandstone can be found between Minnesota and Arkansas and Illinois to South Dakota. St Peter Sandstone is typically poorly cemented; therefore, easily breakable. The color of the sandstone varies depending on its cementing material. At Starved Rock, iron is noted in the cement of the stone, producing red, yellow and orange coloring in some areas.
While sandstone provides beauty to admire, it is also useful for an abundance of other things. It is particularly useful in glass making (glass tiles, chinaware), as an abrasive, a filter medium for water purification, additive in paints, anti-caking agent in table salt. Most recently, it is used heavily in gas and oil production.
Starved Rock State Park received its named from an old Native American Legend. During a battle, a group of Illinois tribe sought shelter at the top of the rocks, corned by their enemy below. The group did not want to come down the cliffs to their death, so they stayed atop, where they all eventually died of starvation (n.d.). Hence, the name Starved Rock.
The 2,000 plus acres of land that surrounds sandstone has been considered a historical landmark since 1960. It is now a popular vacation area and tourist destination and was recently voted the number one attraction in Illinois. However, due to continuous natural (very slow) erosion of the stone, some of the popular hiking trails have been permanently shut down do to unsafe conditions.
References
Gale, D. N. (1970, January 1). Ancient Illinois history beginning on the supercontinent of Pangaea. The Digital Research Library of Illinois History Journal. https://drloihjournal.blogspot.com/.
Tarbuck, E., Lutgens, F., Linneman, S. (2019). Earth: An introduction to Physical Geology.
Pearson.
(n.d.). https://www2.illinois.gov
