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| Tufa towers at Mono Lake, California |
Tufa is the name for an unusual geological formation.
Tufa is a rough, thick, rock-like calcium carbonate deposit that forms by precipitation from bodies of water with a high dissolved calcium content. Tufa deposition occurs in six known ways:
- Mechanical precipitation by wave action against the shore. This form of tufa can be useful for identifying the shoreline of extinct lakes (for example in the Lake Lahontan region).
- Precipitation from supersaturated hot spring water entering cooler lake water.
- Precipitation in lake bottom sediments which are fed by hot springs from below.
- Precipitation from calcium-bearing spring water in an alkaline lake rich in carbonates.
- Precipitation throughout the lake as the lake dries out.
- Through the agency of algae.
There are some prominent towers of Tufa at Mono Lake in California, USA, formed by method 4, above. Tufa is also common in Armenia.
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