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CAVE’S MYSTERY NOW CRYSTAL CLEAR

Following extensive analysis, a team of geologists from Mexico and Spain believe they can explain how giant selenite gypsum crystals in Mexico’s Cueva de los Cristales in the Naica mine complex, 150 kilometres southeast of Chihuahua, were formed. The crystals are among the largest ever found, weighing as much as 55 tonnes and measuring up to 11 metres in length. Analysis of tiny pockets of fl uid found inside the crystals revealed the exact chemical composition and temperature of the water in which they formed, allowing the scientists to deduce that they grew within a narrow temperature range – around 58°C – submerged in mineral-rich water. The scientists now think it’s likely that there are more giant crystals elsewhere in the mine system. The Naica mines yield large quantities of lead, zinc and silver, and the chambers containing the crystals would be submerged by water were it not for the mining activities. “I’ve recommended to the mining company that they try to preserve them and I would like to see UNESCO get involved,” said Professor Juan Manuel Garcia-Ruiz of the University of Granada.

North Sea fl oor was once desirable residence

New images of the North Sea fl oor have revealed a landscape that was once criss-crossed by river valleys and dotted with freshwater lakes and rounded hills, described by one archaeologist as “the best-preserved prehistoric landscape, certainly in the whole of Europe and possibly the world.” The team of archaeologists from the University of Birmingham recreated the landscape by piecing together three-dimensional seismic records collected during the past two years by oil-prospecting vessels across a 23,000square-kilometre area. Based on the fi ndings, the scientists have suggested that the North Sea fl oor would once have supported a wealth of

fauna and fl ora, making it an ideal home for hunter-gatherers – rather than just a bridge between northern Europe and Great Britain, as was previously thought. “This was probably a heartland of population at the time,” said Professor Vince Gaff ney, director of the university’s Institute of Archaeology and Antiquity. In a scenario that bears some resemblance to the current predicted threat from global warming, the area was, said Gaff ney, inundated between 9,000 and 20,000 years ago in a relatively short space of time due to a warming climate. “The area we have mapped was wiped out in the space of 4,000 years,” he said.

COMING SOON: ENCYCLOPAEDIA OF LIFE

A monumental eff ort is being made by several scientifi c institutions to record every plant, animal and other species on Earth in an online encyclopaedia. The estimated 1.8 million species will be entered onto a multimedia website by several institutions, including the USA’s Field Museum, Harvard University and Smithsonian Institution, over the next ten years. The website, www.eol.org, will be accessible to all, and will initially present text, photographs, videos and distribution maps for animals, plants and fungi, with microbial life to follow later. “The Encyclopaedia of Life will provide valuable biodiversity and conservation information to anyone, anywhere, anytime,” said Dr James Edwards, executive director of the project.

8 www.geographical.co.uk JULY 2007

Javier Trueba/MSF/Science Photo Library; HP VISTA (U niversity of Bi rm ingham)