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Morton gneiss

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Color image of Morton gneiss used on the façade of the West Publishing Company building in St. Paul, 2016. Photograph by Paul Nelson.

Close-up of Morton gneiss used on the façade of the West Publishing Company building in St. Paul, 2016. Photograph by Paul Nelson.

Morton gneiss (pronounced “nice”), named for the town in Renville County where it has been quarried, is one of the oldest stones on the planet: about 3.5 billion years old. It is known for its beauty as an ornamental stone in buildings and monuments.

The rock known as Morton gneiss started out as a gray granite, formed about 3.5 billion years ago deep beneath the surface of the Earth. Molten rock cooled slowly, forming grains (granite comes from granum, the Latin word for grain) of crystallized minerals.

About a billion years later, two fragments of the Earth’s crust collided at the future location of southwestern Minnesota, subjecting the granite to heat and pressure. These forces melted it once again and allowed intrusions of molten pink granite. The two granites folded and twisted; when they hardened (very slowly), the twists and folds remained. Eight hundred million years later, another geologic heating event added additional color and texture.

When cut and polished, Morton gneiss shows bands and swirls of black, pink, and gray, with white flecks, that sometimes look like galaxies and nebulae floating in the cosmos. The rock’s colors come from quartz (white), pink feldspar (pink), gray feldspar (gray), and biotite and amphibole (black.)

About one hundred million years ago, geologic forces slowly pushed Morton gneiss to the Earth’s surface. The glaciers that advanced and retreated across southwestern Minnesota between two million and 12,000 years ago covered the rock with hundreds of feet of soil and rock. The last glaciers began receding about 12,000 years ago.

A vast body of water known as Lake Agassiz formed in southern Canada, Minnesota, and North Dakota. When that water drained to the south, forming the River Warren, it carved out the Minnesota River valley. This powerful flow washed away hundreds of feet of glacial deposits and exposed some of the Morton gneiss.

Workers began quarrying this gneiss at Morton, Minnesota, around 1884. In these early years, railroads used it for ballast beneath railroad tracks. In 1886, the Swedish immigrant John Anderson arrived in Morton and took a job as a foreman in the quarry. It was located in the village of Morton, between the railroad tracks and the Minnesota River. By 1900, Anderson owned the quarry. He sold it to Cold Spring Granite Company in 1930.

Though Morton gneiss is as tough and durable as granite, it has rarely been used as a building stone. Architects have used it mainly in the lower floors of large buildings for its visual appeal. It enjoyed its greatest popularity during the Art Deco era of the 1920s and 1930s. Perhaps the most spectacular use of the stone can be found at the Adler Planetarium in Chicago, completed in 1930. Around the country it was used prominently in New York, Detroit, Des Moines, Birmingham, Tulsa, Milwaukee, Hartford, Brooklyn, and Cincinnati. It figures in two buildings at Washington State University in Pullman: Holland Library (1950) and its addition, Terrell Library (1994.)

In the Twin Cities, the stone was used by Northwestern Bell Telephone Company in its downtown Minneapolis and St. Paul headquarters. In downtown St. Paul, it was used at the street level of the West Publishing Company building on Kellogg Boulevard and in the original Ecolab Building at Fifth and Wabasha Streets.

Since the mid-twentieth century, Morton gneiss has been used more for grave markers and mausoleums than for buildings. At the Bird Island Cemetery, in Goodhue County, a free-standing arch of Morton gneiss greets visitors. The Wellstone family marker at Lakewood Cemetery in Minneapolis uses a large, uncut stone.

In Morton, the town’s welcome signs are made of gneiss, as are the front of the town liquor store and panels on the old high school. The stone is so plentiful there that it is used as riprap (erosion-reducing rubble) along ditches and streams.

Zion Lutheran Church may be the only building made entirely of Morton gneiss. The State of Minnesota designated a huge outcrop of the stone, in Morton, the Morton Outcrops Scientific and Natural Area. Visitors there can see Minnesota’s oldest rocks, eroded but unquarried.

Along with Kasota stone, St. Cloud granite, and Platteville limestone, Morton gneiss makes a distinctively Minnesotan contribution to the built environment.

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  • Bibliography
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Aber, James S. “Morton Gneiss, Minnesota.” Emporia State University.
http://academic.emporia.edu/aberjame/tectonic/morton_gneiss/morton.htm

Bowles, Oliver. The Structural and Ornamental Stones of Minnesota. Washington, DC: U.S. Government Printing Office, 1918.

Dominik, John J. Cold Spring Granite: A History. Cold Spring, MN: Cold Spring Granite, 1982.

Ojakangas, Richard. Roadside Geology of Minnesota. Missoula, MT: Mountain Press, 2009.

——— , and Charles L. Matsch. Minnesota’s Geology. Minneapolis: University of Minnesota, 1982.

Weiblin, Paul W. Field Trip Guide for the Precambrian Terrane of the Minnesota River Valley. St. Paul: Minnesota Geological Society, 1982.

Williams, David B. ”Mariner Tower Update,” GeologyWriter.com (blog), February 10, 2010.
http://geologywriter.com/tag/morton-gneiss/

Related Images

Color image of Morton gneiss used on the façade of the West Publishing Company building in St. Paul, 2016. Photograph by Paul Nelson.
Color image of Morton gneiss used on the façade of the West Publishing Company building in St. Paul, 2016. Photograph by Paul Nelson.
Color image of the front façade of the Ecolab building in St Paul, 2016.
Color image of the front façade of the Ecolab building in St Paul, 2016.
Color image of the former Northwest Bell Building in St. Paul, which features Morton gneiss, 2016. Photograph by Paul Nelson.
Color image of the former Northwest Bell Building in St. Paul, which features Morton gneiss, 2016. Photograph by Paul Nelson.
Color image of an outcrop of gneiss in Morton, 2016. Photograph by Paul Nelson.
Color image of an outcrop of gneiss in Morton, 2016. Photograph by Paul Nelson.
Color image of a Morton gneiss headstone in St. Paul’s Oakland Cemetery, 2016. Photograph by Paul Nelson.
Color image of a Morton gneiss headstone in St. Paul’s Oakland Cemetery, 2016. Photograph by Paul Nelson.
Color image of a gneiss boulder in Morton, 2016. Photograph by Paul Nelson.
Color image of a gneiss boulder in Morton, 2016. Photograph by Paul Nelson.
Color image of a gneiss cliffside in Morton, 2016. Photograph by Paul Nelson.
Color image of a gneiss cliffside in Morton, 2016. Photograph by Paul Nelson.
Color image of a sign welcoming visitors to the city of Morton, 2016. The sign is made out of Morton gneiss. Photograph by Paul Nelson.
Color image of a sign welcoming visitors to the city of Morton, 2016. The sign is made out of Morton gneiss. Photograph by Paul Nelson.
Color image of a sculpture made out of Morton gneiss in front of the Harold Stassen Building in St. Paul, 2016. Photographed by Paul Nelson.
Color image of a sculpture made out of Morton gneiss in front of the Harold Stassen Building in St. Paul, 2016. Photographed by Paul Nelson.
Color image of a Haupt Fountain made of Morton Gneiss in Washington D.C., ca. 2016.
Color image of a Haupt Fountain made of Morton Gneiss in Washington D.C., ca. 2016.
Sculpture with Morton gneiss base on the Minnesota State Capitol grounds
Sculpture with Morton gneiss base on the Minnesota State Capitol grounds
Exterior of Minnesota Building with Morton gneiss at sidewalk level
Exterior of Minnesota Building with Morton gneiss at sidewalk level

Turning Point

About 2.6 billion years ago, the collision of two pieces of the Earth’s crust melt gray granite beneath what is now southwestern Minnesota; molten pink granite mixes into the gray.

Chronology

4.6 billion years ago

The Earth forms; it is extremely hot.

4.5 billion years ago

The Earth’s crust forms, on top of and much cooler than the interior mantle.

3.5 billion years ago

Geological forces (heat and pressure) form a field of gray granite beneath what will someday become southwestern Minnesota.

2.6 billion years ago

Two chunks of the Earth’s crust—the Minnesota River Valley Terrane and the Superior province—collide, melting the granite of southwestern Minnesota and allowing intrusions of pink granitic magma.

1.8 billion years ago

Morton gneiss is subjected to intense heat and pressure—a “low grade” metamorphic event.

2 million to 12,000 years ago

A series of glaciers advances and retreats over southwestern Minnesota.

Between 11,600 and 9,600 years ago

A “catastrophic discharge” of water from Lake Agassiz carves out the Minnesota River valley and exposes Morton gneiss to the surface.

Early 1870s

The village of Morton is founded.

1882

The Northern Pacific Railroad reaches Morton.

1884

Quarrying of Morton gneiss begins.

1894

Quarrying is suspended due to a national economic depression.

1900

John Anderson Company resumes quarrying at Morton.

1930

Cold Spring Granite Company buys the Morton quarry.

1930s

The use of Morton gneiss in U.S. construction peaks.

2016

The quarry is only intermittently active.