Cathedral City Pinnacles

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These tufa towers formed underwater between 11,000 and 25,000 years ago. They form when calcium-rich groundwater enters alkaline lake water causing calcium carbonate to precipitate. This slowly forms a calcium carbonate tube or pipe around the groundwater's entry point. Tufa towers stop growing when their tops become exposed, either because they reach the lake's surface or because lake level drops. The tallest of these towers is about 140 feet (43 m) high.