Rare meteorites in Oman
A close-up of Sayh al Uhaymir 169, which is believed to have come from the Imbrium Basin of the Moon.
By Conrad Prabhu
MUSCAT — A lunar meteorite that was discovered in the Sultanate more than two years ago is beginning to reveal secrets of its cosmic journey from the surface of the Moon to the barren deserts of Oman.
Research centring on the Sayh al Uhaymir (SaU) 169, a fist-sized piece of rock which is believed to have been ejected from the lunar surface, is generating ripples of excitement among scientists. An Omani geologist, who along with two others first stumbled upon the meteorite in 2002, says scientists have now been able to pinpoint the exact location on the Moon’s surface from where the rock was catapulted many thousands of years ago.
“Scientific analysis of the meteorite now proves that the rock originated from the Imbrium Basin, a huge crater which is popularly called the right eye of the ‘Man in the Moon’”, said Ali al Kathiri, who is on study leave from the Ministry of Commerce and Industry. “This is the first time that the origins of a lunar meteorite have been charted,” he added in remarks to the Observer.
Al Kathiri, along with fellow geologists Dr Edwin Gnos and Dr Beda Hofmann of the University of Bern (Switzerland), came upon the meteorite in the Sayh al Uhaymir area of Oman’s Sharqiyah deserts on January 16, 2002.
Omani geologist Ali al Kathiri (right) with Dr Beda Hofmann of the University of Bern with the lunar meteorite SaU 169, which they found in the Sharqiyah deserts.
“The meteorite was found during a joint field search project of the Government of Oman, Ministry of Commerce and Industry, the Natural History Museum of Bern (Switzerland), and the University of Bern,” said Al Kathiri.
SaU 169 was one of an estimated 3,700 meteorites discovered during a series of joint field search campaigns undertaken between January 2001 and January 2003, says the Omani geologist. “We invested a total of 339 man-days in the search, which yielded some 1,334 kg of meteorites, which may have come from an original 150-200 individual falls. Meteorites commonly break up in the atmosphere into many smaller fragments.”
Al Kathiri, who is doing his PhD work at the University of Bern, is studying the weathering of ordinary meteorites under different climatic conditions in Oman. He is also studying special meteorites in detail.
SaU 169, says the geologist, is one of only 30 known lunar meteorites. Unlike other lunar rocks, SaU 169’s composition reveals a high content of
radioactive elements comparable to granite. “The meteorite actually consists of two different rock types fused together. The main part of the meteorite (87 per cent) has a unique chemical composition showing unusually high thorium and uranium contents. From Nasa’s Lunar Prospector mission, we know that such elevated thorium values exist around the Imbrium Basin of the Moon. Thus this part of the meteorite has to originate from the Imbrium area.”
Equally fascinating has been the revelation that SaU 169 was part of a larger mass of rock that endured four colossal impacts before having being finally slingshot from the lunar surface. The first impact is believed to have occurred about 3.9 billion years ago when the Imbrium Basin, one of the largest craters on the Moon, was created. The second gigantic blow came around 2.8 billion years ago, while a third impact occurred about 200 million years ago.
SaU 169 took a fourth knock around 340,000 years ago when it was sent hurtling into space. It remained in orbit around the sun for thousands of years before it succumbed to the planet’s gravitational pull and crashed into the deserts of Oman where it lay for about 9,700 years until it was discovered.
According to Al Kathiri, the meteorite’s discovery and the associated scientific revelations will translate into significant benefits for Oman. “These findings will add to Oman’s prestige in the international scientific community, as well as in the general media.
This development will also spotlight Oman as a promising travel destination. Besides, such interesting meteorite finds will enable Omani researchers access to leading research institutions in the fields of geology, physics and chemistry.”
The scientist believes that SaU 169 will finally be returned to the Sultanate after the conclusion of the present scientific investigations. “This scientifically valuable meteorite will perhaps be finally made available for a special and secure exhibition facility,” he commented.
Oman Observer, 17th August 2004
