Have you ever seen the handful of houses in the Huron's Rye Beach neighborhood that are constructed using a strange-looking, porous rock and wondered what exactly it was? The rock is called tufa. Tufa is a porous rock formed by the deposition of calcium carbonate from supersaturated water. According to Mike Angle, a geologist with the Ohio Division of Geological Survey, tufa and its sister, marl, are “a bit of an enigma for geologists to classify.” These rocks differ from all other bedrocks in Ohio because, unlike limestone and other bedrocks that are millions of years old, they are still being formed. Tufa, a soft, volcanic-looking rock that ages and hardens in the sun, is essentially a porous deposit of calcium carbonate. “It will form anywhere where ground water is super-saturated with calcium carbonate” states retired Ohio geologist, Nate Fuller. When the precipitation of the calcium carbonate occurs underground, marl is formed. When it precipitates out above ground, tufa is formed. Upon settling, the carbonate encrusts those objects with which it comes in contact.
Large deposits of tufa and marl are fairly rare and not very widespread; yet, small quantities of tufa rock can be found throughout western and northern Ohio. Deposits of tufa and marl are associated with areas containing caves or caverns and/or seeps or springs along relatively steep slopes and valleys. In Ohio, the largest deposits of tufa were traditionally found at White’s Landing, the Resthaven Wildlife area just northeast of Castalia, and the area around Miller’s Blue Hole, all in Erie County near Sandusky Bay.
In all areas where it occurs, the majority of the tufa and marl has been mined. At Resthaven, the largest deposit in the state, tufa/marl initially covered an area of about 3,500 acres and averaged six feet deep. This area was mined extensively in the early 1900s by the Portland Cement Company of Sandusky for use in their cement products. At White’s Landing and other areas, including Huron’s Rye Beach neighborhood and the Catawba Cliffs neighborhood, the tufa/marl was used primarily in the construction of homes, most of which were constructed during the 1920s and 1930s. Today, tufa is used widely in rock gardens around the world and provides a perfect substrate upon which to grow plants including Dianthus, Hosta, and Phlox.
I lived in White's Landing in Sandusky County in Ohio as a child and grew up knowing and seeing lots of tufa rock houses and some houses encrusted with globs of molten glass. Where did the glass come from? We used to try and break some off the houses that weren't used during the winter.
ReplyDeleteI know exactly what structure you are talking about. It was across the street from paseka's. And across the street where I lived.
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