Images Dated 18th June 1998

Fisheye view of tufa formations at Mono Lake, USA

Limestone tufas. Fisheye view of Mono Lake, California, USA, showing large tufa limestone formations. Tufas are columns or blocks of soft limestone, which here grow to a height of about 14 metres. They are formed by calcium carbonate being deposited from solution at a geothermal spring or by the evaporation of circulating water. Mono Lake is a salt lake which is slowly drying. Although it has no outflow, the water feeding the lake is being diverted at an increasing rate. This puts a great stress on the lake's wildlife, particularly migrating waterfowl

© DAVID NUNUK/SCIENCE PHOTO LIBRARY