Onawa in Monona County, Iowa — The American Midwest (Upper Plains)
Onawa Freedom Rock Veterans Memorial
Monona County Freedom Rock
— -- Ray “Bubba” Sorensen II -- —
Monona County's Freedom Rock
Many Americans think of Iowa as having little topographic variation. However, in westernmost Iowa the Loess Hills rise 200 feet above the flat plains forming a narrow band running north-south 200 miles along the Missouri River. The steep angles and sharp bluffs on the western side of the Loess Hills are in sharp contrast to the flat rectangular crop fields of the Missouri River flood plain. From the east, gently rolling hills blend into steep ridges.
Loess (pronounced "luss"), is German for loose or crumbly. It is a gritty, lightweight, porous materiel composed of tightly packed grains of quartz, feldspar, mica and other minerals. Loess is the source of most of our Nation's rich agricultural soils and is common in the U.S. and around the world. However Iowa's Loess Hills are unusual because the layers of Loess are extraordinarily thick, as much as 200 feet in some places.
The extreme thickness of the loess layers and the intricately carved terrain of the Loess Hills make them a rare geologic feature. Shaanxi, China is the only other location where loess layers are as deep
Original of the Loess Hills
Although early geologists assumed loess was either Fluvial (deposited by a river) or Lacustrine (formed in a lake), today we know that loess was colian (deposited by the wind). During the Ice Age, glaciers advanced down into the mid-continent of North America, grinding underlying rock into a fine powder-like sediment called "glacialflour." As temperatures warmed, the glaciers melted and enormous amounts of water and sediment rushed down the Missouri River valley. The sediment was eventually deposited on flood plains downstream, creating huge mud flats.
During the winters the melt waters would recede, leaving the mud flats exposed. As they dried, fine-grained mud material called silt was picked up and carried by strong winds. These large dust clouds were moved eastward by prevailing westerly winds and were redeposited over broad areas. Heavier, coarser silt, deposited closest to its Missouri River flood plain source, formed sharp, high bluffs on the western margin of the Loess Hills. Finer, lighter silt, deposited farther east, created gently sloping hills on the eastern margin.
"Peculiar," "irregular," and "uncommon," are words used to describe one class of Iowa rocks - glacial boulders or "erratics." Geologists define erratics as stones or boulders that have been carried from their place of origin by a glacier and then left stranded by melting ice on bedrock of a different composition. In Iowa, glacial erratics are commonly observed where glacial deposits occur at the land surface. In western and southern Iowa, erratics (like Monona County's Freedom Rock) generally lie buried beneath wind-deposited silts (loess) that cover the glacial materials. In these areas, erratics generally are restricted to valleys, where streams have eroded through the loess and into the underlying glacial deposits.
The Loess Hills are comprised of three major layers. From oldest to youngest, the layers are known as the Loveland Loess, (120,000 to 159,000 years old), the Pisgah Loess (25,000 to 31,000 years old), and the Peoria Loess (12,500 to 25,000 years old). Clues in the loess layers help geologists determine the rate at which the loess was deposited. For example, ripples mean accumulation took place very quickly. Thin dark bands in the loess indicated
A large-scale example of a boulder train that can be observed in Iowa is the distribution of glacial erratics composed of the distinctive Sioux Quartzite, a very hard, uniformly pink rock. Outcrops of this Precambrian-age, quartz-rich rock occur in the extreme northwest corner of Iowa and on across the border into southwest Minnesota, where thy span an area from the town of New Ulm, westward to Mitchell, South Dakota. Since the glacial ice that moved through northwestern Iowa traveled generally southward, erratics of Sioux Quartzite are most common in the area east and southwest of Estherville (south of New Ulm, Minnesota) and are generally absent east of there. Another example of a boulder train involves rare diamonds recovered from some Midwestern glacial deposits. Attempts to trace them back to a northern source area, hover ever, have been unsuccessful.
In western Iowa, erratics generally lie buried beneath wind-deposited silts (loess) that cover the glacial materials. In these areas, erratics generally are restricted to valleys, where streams have eroded through the loess and into the underlying glacial deposits. This ice melted away about 12,500 years ago, leaving a significant number of boulders (like Monona County's Freedom Rock) across the Iowa landscape. This region known as the Iowan Surface, was left with loess deposits mantling steeply rolling terrain composed of glacial materials deposited in Iowa over 500,000 years ago.
Monona County's Freedom Rock is a 432 cubic foot solid granite stone
The "Freedom Rock" was painted by artist Ray "Bubba" Sorensen II on August 17-25, 2016. This project was coordinated by the Monona County veterans Memorial Museum Executive Director/Curator William A. Wonder.
Our sincerest thanks to these sponsors and to everyone who contributed to this project:
Northern Age Elevator, Knight Concrete, Niewohner Construction, Schroder Towing, Kuhlmann Collision Center, C & H Towing/Crane Service, M & M Construction, City of Onawa, Monona County Supervisors, Monona County Community Partner's Foundation, Monona County Conservation Board, Monona County American Legion, Monona County Legion Auxiliary, Museum County Veterans Board, Onawa Super 8 Motel, Jordan Tree Farm, The Garage Mahallics, Iowa DNR Little Sioux, Joseph Scurlock, and all the Private Donors.
Onawa Freedom Rock Illustrations
They gave their tomorrow for our today.
[WWII bomber and a few Hueys and some silhouetted ships in the background. In the foreground it is a flag draped coffin and a soldiers cross]
_ _ _ _ _ _ _ _ _ _
Cpl. Llythaniele Fender
[Llythaniele Fender was killed in 2007]
_ _ _ _ _ _ _ _ _ _
2nd Lt. Archie Steen
[Archie Steen, WWII Veteran]
Marker series. This marker is included in the Iowa Freedom Rock Memorials marker series.
Location. 42° 2.198′ N, 96° 5.957′ W. Marker is in Onawa, Iowa, in Monona County. Marker is at the intersection of 12th St and Gaukel Dr on 12th St. Touch for map. The memorial is located in the city park. Marker is at or near this postal address: 300 12th St, Onawa IA 51040, United States of America. Touch for directions.
Categories. • Environment • Patriots & Patriotism • War, Afghanistan • War, World II •
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Credits. This page was last revised on June 25, 2019. This page originally submitted on June 25, 2019, by Ruth VanSteenwyk of Aberdeen, South Dakota. This page has been viewed 38 times since then. Photos: 1, 2, 3, 4, 5, 6. submitted on June 25, 2019, by Ruth VanSteenwyk of Aberdeen, South Dakota. • Bill Pfingsten was the editor who published this page.