Sunday, November 23, 2025

I have finally got around to looking up why the roads in my hometown were purplish, not typical gray


The one place in the world that has Kona Dolomite, which, is in the Kona Hills near Marquette, Michigan.


That's about 60 miles from where I grew up

The asphalt in the Yoop used to use the reddish hue crushed rock called Kona Dolomite as aggregate in asphalt.

Most dolomite found throughout the world is gray or white. Kona dolomite is quite colorful and is found nowhere else. Dolomite is a calcium limestone with magnesium added.

Kona Dolomite pink and reddish tones come from iron oxide absorbed during its formation around 2.1 to 2.2 billion years ago.

The use of local stone is common because shipping aggregate is expensive, road color varies depending on the local geology, such as the red roads in Arizona from iron, and copper-rich stone, or the pinkish/reddish roads in parts of Michigan that used Kona Dolomite


2 comments:

  1. When I-95 was built in Connecticut - It was first the Connecticut Turnpike, as soon as one drover east into New Haven County, the concrete was a reddish brown. This is attributed to the local earth that stretches north to Hartford and this earth is well known for being ideal for growing tobacco. The "Connecticut Wrappers" are used for cigars.

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  2. Interesting story and back story. Next roll thru to Minnesota, I will check it out!

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