x Abu Dhabi, UAEThursday 18 January 2018

Deserts are ideal to find meteorites

The team leader of researchers says conditions in the UAE are perfect for preserving the rocks that offer a window on the solar system's creation.

One of 26 chrondite meteorites found during a two-week search in Abu Dhabi early last year. Scientists believe that other samples might have been removed by oil workers over the years.
One of 26 chrondite meteorites found during a two-week search in Abu Dhabi early last year. Scientists believe that other samples might have been removed by oil workers over the years.

ABU DHABI // It may be one of the world's most inhospitable environments for man, but conditions in the scorching deserts of southern Abu Dhabi are ideal for preserving the fragments of rock and metal that plummet to the Earth's surface from space.

With little rainfall to corrode them, and scant change to the landscape, meteorites can lie undisturbed in deserts for millennia. Thousands have been found in the Empty Quarter in Oman and the deserts of Libya, but until last year there had been no official survey in the UAE. The findings of a two-week expedition conducted by a team from the University of Hamburg, the Environment Agency-Abu Dhabi and the UK's Natural History Museum in the emirate's southern deserts last March were recently published. The team of nine found 26 strewn across the area.

"This proves that the UAE belongs to the group of states which are lucky to have sites where meteorites are concentrated," said Prof Jochen Schlüter, the curator of the University of Hamburg's Mineralogical Museum and an expert on meteorites, who led the team. "It's a good amount to find."  The decision to do the survey came after two meteorites were discovered in the southern deserts of Abu Dhabi in 2005. Heiko Kallweit, a German archaeologist, was searching for neolithic sites when he made the first official discovery of a meteorite in the UAE. It was a ureilite, particularly rare, forged from rock, graphite and diamond.

The find of UAE 001 led experts to wonder whether the deserts hid more of these scientific treasure troves, which hold information about the creation of the solar system. "Meteorites fall all over the world in the same way and the same amount, but in most instances, if you don't find them straight away, they weather and in 10 to 20 years they are gone," said Prof Schlüter. "But in the desert, there's no rain to weather them and for a long, long time there's been no change in the Earth's surface - they can be preserved for thousands of years."

Most meteorites are about 4.5 billion years old, dating back to the creation of the solar system, and the majority come from the asteroid belt. They are considered to be the building blocks from which our solar system was formed.   "Meteorites are the ingredients and the Earth and the Moon and the Sun are the cake," Prof Schlüter said. "Meteorites - they were there at the beginning."   Small sections of each meteorite were sent to the University of Hamburg and London's Natural History Museum for analysis, but the bulk of each will remain in the UAE. 

"It's important the main masses stay here. We think of them as a natural treasure, part of the country's heritage," Prof Schlüter said.    All 26 found during the survey, which ranged from a weight of 7g to 540g, were chrondites - stony meteorites despite their nickel-iron content. Ninety-five per cent of all meteorites found are stony, while four per cent are metallic and the remainder a mix. One reason metallic meteorites are rare is that they have been picked up through history and used for tools. 

The rarest meteorites of all, experts say, are those blasted off Mars or the Moon by other impacts. Fewer than 50 have been found. Martian and lunar meteorites are particularly precious because they allow scientists to glean information about these bodies without the expense of sending a space mission there.  By measuring the amount of cosmic radiation, scientists can calculate how long a meteorite has lain on the Earth. Some have been found to have an "Earth age" of up to 35,000 years.

"One purpose of this research study is to help understand the geological formations in the area. This will be possible when the terrestrial age of the meteorites is determined," said Osama al Fakeer, an assistant manager at the environment agency who took part in the survey. The co-ordinates of the meteorites were plotted, so the scientists can deduce whether they were parts of a "scatter field", created when a large meteor shatters as it blasts through the atmosphere. Some of the finds are suspected to have been part of the same meteor. "We found two pieces about two metres apart that fit together perfectly," Mr al Fakeer said. A further study will be carried out in November. @Email:lmorris@thenational.ae