Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Meteorite from Oman Records Its Lunar Launch Site and Detailed History

30.07.2004


This is how meteorite SaU 169 looked when its discoverers initially inspected it in the lab. The maximum dimension is 7 centimeters, or not quite 3 inches. (Photo: Peter Vollenweider)


Photo from the joint Swiss - Omani meteorite search expedition in 2002 (Photo: Edwin Gnos)


Scientists have pinpointed the source of a meteorite from the moon for the first time. Their unique meteorite records four separate lunar impacts.

They are the first to precisely date Mare Imbrium, the youngest of the large meteorite craters on the moon. That date, 3.9 billion years ago, is a new key date for lunar and even terrestrial stratigraphy, the scientists say, because life on Earth would have evolved only after heavy meteorite bombardment ended.

Geologists who found the meteorite and scientists from Swiss, Swedish, German, British, and Arizona laboratories who analyzed the unique stone report their work in the July 30 issue of Science. Swiss geologist Edwin Gnos is first author of the article titled "Pinpointing the Source of Lunar Meteorite: Implications for the Evolution of the Moon."



Gnos, Ali Al-Kathiri and Beda Hofmann found the 206-gram (7-ounce) meteorite in Oman on Jan. 16, 2002. The geologists were on a joint meteorite search expedition sponsored by the Government of Oman, the Natural History Museum of Berne and the University of Berne.
This is how meteorite SaU 169 looked when its discoverers initially inspected it in the lab. The maximum dimension is 7 centimeters, or not quite 3 inches. (Photo: Peter Vollenweider)

"The desert in Oman is the new place to find meteorites," said A.J. Tim Jull of the University of Arizona in Tucson. Jull directs the National Science Foundation – Arizona Accelerator Mass Spectrometry (AMS) Laboratory. He analyzed beryllium and carbon isotopes that told how long the meteorite was in space after it was launched from the moon and how long ago it fell to Earth at Oman.

Scientists who’ve acquired the special permits needed to search for meteorites in Oman and North Africa during the past half-dozen years have been amply rewarded, Jull said. Seven of the 30 known lunar meteorites have been found in Oman, and five have been found in North Africa. One was found in Australia and the rest have been found in Antarctica. Hot or cold, arid climates preserve meteorites from quickly weathering, Jull noted.
Gnos, Al-Kathiri and Hofmann recognized in the field that the meteorite was of lunar or martian origin because it wasn’t magnetic. Meteorites from planetary bodies don’t contain metal. And, typical of lunar rocks, it was greenish colored and contained white angular feldspar inclusions.

But when they tested it with a Geiger counter, they found it was no typical lunar rock. They found it contained high levels of radioactive uranium, thorium and potassium. Gamma ray-spectroscopy lab tests told them that the ratios between these elements fit only one enigmatic group of lunar rocks called "KREEP," the acronym of K for potassium, REE for rare earth elements, and P for phosphate.

"At that moment, it was clear that the rock had something to do with the large Imbrium impact basin, the right eye of the man in the moon," Gnos et al. report on the Web at http://www.geo.unibe.ch/sau169. The Imbrium impact basin on the lunar nearside is the only area where KREEP rocks are found. KREEP rocks are known both from samples returned by the Apollo missions and by NASA’s Lunar Prospector Orbiter radioactivity survey in 1998-99.

Tim Jull (right), discusses isotope analysis results at the NSF-Arizona AMS lab at the UA in Tucson. (Photo: Lori Stiles)

The scientists conducted a battery of laboratory tests to piece together a detailed history of the meteorite, named Sayh al Uhaymir (SaU) 169. They summarize SaU 169’s history:

At 3.909 billion years ago, plus or minus 13 million years – An asteroid collides with the moon, forming the 1160 km (720-mile) diameter Imbrium impact basin. Crushed and molten rocks mix and solidify to form the main rock type in meteorite SaU 169.
At 2.8 billion years ago – A meteorite hits the moon, forming the 25 km (15-mile) diameter Lalande crater south of the Imbrium basin. The impact blasts material, including the main rock type in SaU 169, from depth and deposits it as an ejecta blanket around the crater. The ejecta there mixes with other lunar soil.

At 200 million years ago – Another impact brings the rock that will become a meteorite to within a half-meter (20 inches) of the lunar surface.

At less than 340,000 years ago – Another impact hits the moon, producing a crater a few kilometers in diameter and ejects SaU 169 from the moon. The scientists studied NASA images and identified a young, 3 km (1.8-mile) diameter crater 70 km (43 miles) north-northeast of Lalande as the meteorite’s likely launch site. Jull measured beryllium 10 in SaU 169 and determined the meteorite’s moon-to-Earth transit time at around 300,000 years. He also measured carbon 14 in SaU 169, which shows the meteorite fell in present-day Oman around 9,700 years ago, plus or minus 1,300 years.

Edwin Gnos

"Without the Apollo and Luna sampling programs, and especially the huge advance in knowledge of the Moon acquired during investigations in the last 20 – 30 years, we would only be able to tell that SaU 169 is an exceptional lunar rock," the scientists said on their Website. "Without background information from such missions as Clementine and Lunar Prospector, we could never have linked ages and chemical data with lunar surface information." "SaU is a rock which demonstrates impressively how rocks can travel, like a ping-pong-ball, from one body to another," they said.

Lori Stiles | EurekAlert!
Further information:
http://www.arizona.edu

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>