These notes are derived from the web page created by Nancy Hubbard (architecture), Tim Grundl and Bill Kean ( Geosciences). The web page link is http://people.uwm.edu/urban-geology/. The site has more buildings and some more detail. The link to this specific tour can be found at https://sites.uwm.edu/wkean/ under geology tours, or directly at https://sites.uwm.edu/wkean/downtown-mke-building-stone-tour/ . This gives pictures and more details of the buildings on this specific tour.
Main Points to keep in mind as we tour
1. Different building stones are used for aesthetics and/or support of the building
2. Most building stones are “local” because shipping is expensive
3.Rocks (stones) tell a story of their origin and history.
4. Midwestern rocks tell us the region has had high mountains, volcanic eruptions, and at times was part of a shallow warm ocean. Most recently it was covered by ice that has since melted.
1. Pfister Hotel
Architects: Henry C. Koch and Herman J. Esser 1892-1893
The Pfister Hotel is among the last buildings to use the local Wauwatosa Limestone in its construction. The production of Wauwatosa limestone for building stone declined after the mid-1890s
2. Milwaukee Club
Architects: Edward Townsend Mix 1884
3. Northwestern National Insurance Company Building
Architects: Ferry & Clas 1904-1906
The building was designed in the Beaux-Arts style, and constructed of smooth-faced Bedford (Indiana) Limestone from Bedford, Indiana.
4. Wisconsin Gas Building
Architects: Eschweiler and Eschweiler 1929-1930
The two-story base in made of Morton Gneiss (Rainbow Granite). The pinkish buff stone used for trim and ornamentation at the setback levels is Mankato-Kasota Limestone,
5. Northwestern Mutual Life Insurance Company Building
Architects: Marshall & Fox (Chicago) 1912
The almost-uniformly white granite of the exterior is the Bethel White Granite coming from quarries in Woodbury, Vermont
6. Old Federal Building
Architects: Willoughby J. Edbrooke/James Knox Taylor 1892-99
The granite used in the building is a mix of Athelstane Granite from Wisconsin at the base, Mt Waldo Granite above from Maine and Rockville White from Rockville, Minnesota.
7. Northwestern Mutual Life Insurance Company
(Loyalty Building)
Architects: Solon S. Beman (Chicago) 1885
Hallowell and Fox Island Granites from Maine at the base, Indiana Limestone above.
8. Chamber of Commerce Building (Grain Exchange)
Edward T. Mix (1879-80)
Base is rusticated granite (source unknown), The top is gray Berea Sandstone from Ohio
9. Mitchell Building
Edward T. Mix (1876)
Base is granite (probably the same as Grain Exchange), and the top is gray sandstone (Berea Sandstone), the roof has slate shingles.
10. State Bank of Wisconsin/Bank of Milwaukee
Architects: Mygatt & Schmidtner (west: State Bank of Wisconsin) 1856
Albert Nash (Cincinnati) (east: Bank of Milwaukee) 1858
The stone used in construction of both buildings was a northeastern Illinois dolomite known as the Joliet Limestone.
11. Marcus Center for the Performing Arts
Architects: Harry Weese & Associates (Chicago) 1966-1969, Kahler Slater Torphy (with Robert Davis, New York), Engberg Anderson Design Partnership1994-1997
In 1994, the Marcus Center Italian travertine was replaced with two different stones. A lower course of Diamond Beige Granite is topped with exterior walls of Winona Travertine, quarried near Winona, Minnesota.
12. 1000 North Water Street Building
Architects: Harwood K. Smith & Partners (Dallas) 1991
The steel frame of the 12-story building is clad in pinkish Lac du Bonnet Granite, with a polished surface on the lower three floors and honed on the upper floors. The granite was quarried in Lac du Bonnet, Manitoba by the Cold Spring Granite Company.
13. Red Arrow Park Monument: Name for the Red Arrow Division of the Wisconsin and Michigan National Guard that served in both WWI and WWII.
Wisconsin Red Granite (Wausau Red)
14. City Hall
Architects: Henry C. Koch and Co. 1893-1896
The base of City Hall is constructed of striated Berea Sandstone. The upper floors of the building are constructed of buff-orange pressed brick. The architectural style is Flemish revival
15. Frank Zeidler Municipal Building, 41 N. Broadway
Architect: Eschweiler and Eschweiler 1959, 10 story Modern style
Building Material is Wisconsin red Granite (Wausau Red) columns and at the street levet on Broadway Duluth or Mellen Gabbro.
Athelstane and Amberg Granites: These granites come from nearby towns in northeastern Wisconsin, just south of the Michigan border. They are similar in grain size, but the Amberg is more gray, whereas the Athelstane is more pink. They both formed as intrusive bodies of rock that formed the core or subsurface of volcanic islands some 1840-1890 million years ago, when northern Wisconsin looked more like the Japanese Islands do today. These granites were a few of many granites quarried in Wisconsin. In fact Red Granite is the State rock. Today one can visit a small museum in Amberg, which documents the local quarry industry. You are encouraged to see some of the rock in its “natural” state at the Joe Davies county park just off Highway 141 near Amberg.
Bedford Limestone: This sedimentary rock is formally known as the Salem Limestone, but also simply as Indiana Limestone. It is quarried in south central Indiana between Bloomington and Bedford. It was originally deposited in a warm shallow marine environment during Mississippian time (320-360 million years ago). The fine oolitic texture would suggest the sediments were subjected to wave action and marine currents sufficient to winnow the fossil fragments to a uniform size. If one looks closely at the stone you will see it is composed almost entirely of small fragments of marine shells. The Salem Limestone has been used extensively for buildings for over 100 years because of its uniform texture and ease of working. It is fairly soft and can easily be shaped with carving tools.
Berea Sandstone: This sandstone comes primarily from north-central Ohio in the vicinity of Berea, near Cleveland. The sandstone is part of the Bedford-Berea sedimentary sequence, which extends from Pennsylvania to Kentucky. It is of Mississippian age, but slightly older than the Bedford Limestone. The quarry stone is thickly bedded and frequently shows depositional structures such as cross bedding, and current ripples. Its uniform texture over great thickness and ease of cutting into dimensional stone has made it a prized building material for over 100 years.
Bethel White: This coarse grained igneous rock is a type of granitic rock that is specifically identified as a quartz monzonite. It is quarried near the town of Bethel, Vermont. The Vermont granitic rocks are much younger than the rest of the granitic rocks seen in this field trip. The age of this rock is ~335 m.y. which places it in the middle of the Mississippian Period (mid Paleozoic Era).
Carnelian Granite: This coarse-grained igneous rock is a true granite of Early Proterozoic age (about 2000 m.y.). It is quarried near the town of Milbank, South Dakota. The main minerals evident in the rock are quartz, potassium feldspar, plagioclase feldspar,and biotite. Trace amounts of zircon, apatite and hornblende also occur. The rock also displays “myrmekite”, a wart-like growths of plagioclase and quartz that extends into neighboring potassium feldspar grains. This distinctive feature typically occurs during the later stages of the crystallization process.
For those of you who are petrologists, this rock contains anomalously high amounts of strontium and zinc. It appears to have formed from an andesitic rock at just above the minimum melting temperature.
Diamond Beige: This porphyritic igneous rock is a true granite of Early Proterozoic age (1700-1800 Ma). It is quarried near the town of St. Cloud Minnesota. The main minerals evident in the rock are quartz, potassium feldspar, plagioclase feldspar and biotite. Smaller amounts of zircon, apatite, hornblende, chlorite and sericite also occur. The potassium feldspars are the large crystals (“phenocrysts”) set in an otherwise equi-granular matrix.
Hallowell and Fox Island Granite: The Hallowell Granite is a coarse-grained igneous rock that is primarily a biotite-muscovite granite. It was quarried in the town of Hallowell, Maine near the banks of the Kennebec River. The rock crystallized 380-390 m.y. ago, which places it in the middle Devonian. The main minerals evident in the rock are white orthoclase feldspar, quartz, biotite and muscovite. The overall color is very white with a uniformly fine-grained texture. The Fox Island Granite is a very similar rock quarried on the Fox Island near the mouth of the Sheepscot River.
Joliet Limestone: This rock is another Silurian age building stone of the Midwest. Its primary source is a quarry in Batavia, Illinois, which is just west of Chicago near Aurora. The stone is also known as Joliet Marble and Athens Marble, although it is not marble. These other names indicate that similar rock was quarried in those nearby towns. It tends to weather to a buttery yellow color which is not true of Waukesha Dolomite quarried in Wisconsin.
Lac Du Bonnet: This coarse-grained igneous rock is a type of granitic rock that is specifically identified as a quartz monzonite. It is quarried near the town of Pinawa, Manitoba Canada. The rock crystallized 2700 m.y. ago, which places it in the Late Archaean. The main minerals evident in the rock are potassium feldspar, plagioclase feldspar, quartz, sericite, biotite, and muscovite. Smaller amounts of chlorite, epidote, zircon and apatite also occur. The presence of minerals such as sericite and chlorite indicate that the rock has undergone a phase of secondary alteration after it initially crystallized.
For those of you who are petrologists, this rock contains relatively high amounts of uranium and thorium. Being a quartz monzonite (or adamellite), the rock contains intermediate amounts of the alkali elements (sodium and potassium) and calcium. The extrusive equivalent is rhyodacite.
Lake Superior Sandstone: This sandstone that is mostly red or brown in color comes primarily form the Bayfield Group of sedimentary rocks that are found near Bayfield, Wisconsin and on the Apostle Islands in Lake Superior. The bass Island Sandstone is one example. the sandstone of choice in this group is mostly a red feldspathic (has feldspar as a dominant mineral) sandstone deposited as the final stage of the infilling if the Keweenaw Rift. It is presently considered to be the last Precambrian event in Wisconsin which makes it about 1040 million years old.
This reddish sandstone looks similar to the popular “brownstone” used in many east coast row-houses, churches and government buildings, which made it popular as a building stone in the Midwest. It is not always the hardest or well-cemented rock, so it is susceptible to weathering. This is evident on the Milwaukee Club and the Button Block building in Milwaukee’s downtown area, where the sidewalk is sometime a little red from the decaying stone, and small pieces have fallen to the street.
Mankato-Kasota Limestone: This sedimentary rock is part of the Oneota Dolostone Formation of southern Minnesota. It is quarried near the town of Mankato, Minnesota. The age of this rock is ~ 450-500 Ma. which places it in the lower Ordovician Period. The rock is a very fine-grained yellowish tan dolostone consisting almost entirely of dolomite. The high dolomite content means that, for a sedimentary rock, it is relatively resistant to weathering and is therefore widely used as a building stone. The Oneota dolostone was laid down in a shallow embayment of an ancient Ordovician Sea. It contains relatively few fossils and for this reason it has been suggested that this embayment was hypersaline and could not support a wide range of life forms.
Mt Waldo Granite: This is the primary granite on the front of the building. It is from the northern Penobscot Bay region of Maine. The Mt Waldo Batholith is a late Devonian (~371 Ma) felsic pluton. It is considered a true granite because of the approximate equal proportions of quartz, alkali feldspar and plagioclase feldspar. (Gabriela Moroz 2021). Mt Waldo Granite has been used for many buildings on the east coast as well as the Midwest, such as U.S. Senate Office Building, Philadelphia Mint and buildings in the Midwest. The quarry ceased operations in 1914.
Morton Gneiss (Rainbow Granite): This metamorphic rock is a migmatitic gneiss of Archaean age (about 3600 Ma). This means that it is one of the oldest rocks that have ever been dated and is certainly the oldest rock in wide use as a decorative building material. It is quarried near the town of Morton, Minnesota. The primary minerals present in this rock are quartz, potassium feldspar (microcline), plagioclase feldspar and biotite. At one time this rock was very close to melting and the swirly, contorted banding that is so evident is due to plastic deformation near the melting point of the rock.
Rockville White: This coarse-grained igneous rock is a true granite of Early Proterozoic age (~1730 Ma). It is quarried near the town of Rockville, Minnesota. The main minerals evident in the rock are quartz, potassium feldspar (microcline), plagioclase feldspar, and biotite. Smaller amounts of zircon, apatite, hornblende, chlorite, sericite and sphene also occur. The texture is porphyritic with large crystals of potassium feldspars (“phenocrysts”) set in an otherwise equi-granular matrix. The rock is very chemically and petrologically very similar to Diamond Pink. The main difference is the absence of pink color in the feldspars.
Wauwatosa Limestone: This dolomitic rock is most frequently referred to as limestone, in spite of its composition of calcium and magnesium carbonate. It is also known as Niagarian Dolomite, because it is the same rock unit that caps Niagara Falls in Western New York. It is used throughout eastern Wisconsin for buildings and roadwork because it is close to the surface and easy to quarry. It forms the prominent ridge that runs form Door County through Milwaukee and Waukesha and continues just below the surface though Racine and Chicago. It is middle Silurian age (450 million years old) and noted for the ancient coral reefs that are found in it. The reef structures provide clues to Wisconsin’s past environment, suggesting that Wisconsin was once part of a shallow tropical ocean. The Milwaukee Public Museum has an exquisite diorama showing life on a Silurian reef. Fossils form quarries in S.E. Wisconsin can be viewed in the Greene Gallery on the UWM campus.
The rock tends to be light tan to gray in color and fairly compact or dense. This makes for an ideal building stone, especially since it is close to home.
Winona Travertine: This sedimentary rock is part of the Oneota Dolostone Formation of southern Minnesota and as such is essentially the same rock as the Mankato-Kasota Limestone
Woodbury Granite: This coarse-grained igneous rock is a true granite that is quarried near the town of Woodbury, Vermont. The Vermont granites are much younger than the rest of the granitic rocks seen in this field trip. The age of this rock is ~300 m.y. which places it in the Mississippian Period (mid Paleozoic Era). It is very similar to the Bethel White quartz monzonite, but with a little more silica content.
Wisconsin Red Granite: This fine to course grained granite is part of the 1830-1850 Ma granites in the state.