The Sugar Run Dolomite is a
geologic formation in
Illinois. It is a finely-bedded
dolomite, preserving
fossils
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
dating back to the
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...
period. This formation is named for the Sugar Run stream in
Joliet, along which it is well exposed. The dolomite is off-white/grey on freshly cut surfaces, but over time oxidizes to a distinctive cream yellow color, due to trace presence of iron. It is a member of the
Niagran series.
Use in architecture
This formation has been quarried for building material since the mid-19th century, sometimes sold under the misleading trade name of "Athens marble". It is also known as Joliet or
Lemont limestone.
It was used widely in the construction of many Chicago homes and buildings from the 1850s-1880s, including the famous
Chicago Water Tower. By the 1890s, it fell out of fashion as a building material in favor of more durable
Indiana limestone.
See also
*
List of fossiliferous stratigraphic units in Illinois
*
Lannon stone
Lannon stone is a type of buff-colored, blocky, sedimentary Dolomite (rock), that's name is derived from Mr. William Lannon, one of the original settlers of the Village of Lannon, Wisconsin. Lannon stone can be found throughout the Niagara Escarpm ...
References
*
Silurian Illinois
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