Alex Hyde / Water cascading over naturally formed tufa dam. Tufa is a kind of limestone, formed from the precipitation of carbonate minerals which builds up around mosses and water plants to form a solid limeston...
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Claudio Contreras / Hierve el Agua rock formation with calcified minerals, resembling a waterfall. Oaxaca, southern Mexico.
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Graham Eaton / The Carboniferous age Limestone escaprpment of Warrendale Knotts near Settle, North Yorkshire, UK, October
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David Fleetham / Red encrusting sponge (Clathria sp) on calcium carbonate-producing Seaweed / Green algae (Halimeda kanaloana). Hawaii.
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Graham Eaton / A PDC (polycrystalline diamond compact) type oil field drill bit on one othe Kimmeridge ledges. Kimmeridge Bay, Dorset, UK, March. The ledges are hard Jurassic age, carbonate rich horizons of Limetone...
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Pascal Tordeux / Wall formed by stream full of carbonate minerals which caused petrification, Baslieux Les Fismes, Marne, France
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Pascal Tordeux / Wall formed by stream full of carbonate minerals which caused petrification, Baslieux Les Fismes, Marne, France
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Floris van Breugel / Tufa towers along Mono Lake, which form as sodium carbonate reacts with calcium rich spring water. Mono Lake, California, USA. June 2017.
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Floris van Breugel / Tufa towers along Mono Lake, which form as sodium carbonate reacts with calcium rich spring water. Mono Lake, California, USA. September.
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Floris van Breugel / Carbonate minerals in ancient volcano north of Lake Mono, seen here at night under ultraviolet illumination. Mono Lake, California, USA. June 2017.
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Floris van Breugel / Tufa towers along Mono Lake, which form as sodium carbonate reacts with calcium rich spring water. Mono Lake, California, USA. June 2017.
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John Cancalosi / Leesburg conglomerate rock, a grey carbonate pebble conglomerate in a red sand-silt matrix. Leesburg , Virginia, USA.