Curtin geologists make a 'shocking' discovery

January 24, 2012 By Andrea Barnard

Research led by Curtin University geologists has uncovered a wealth of new evidence in the mineral zircon from lunar rock samples recovered during NASA’s Apollo missions, revealing indisputable proof of meteorite collisions on the Moon.

Headed by microstructural geology experts Dr. Nick Timms and Professor Steven Reddy of the Western Australian School of Mines (WASM), the study documents the discovery of impact-related shock features in lunar zircon, giving scientists a new conceptual framework to explain the history and timing of events in our solar system.

Dr. Timms said the discovery was made while looking more closely at lunar zircon mineral grains, with the use of microscopy facilities at Curtin, and finding the presence of preserved microscopic details, known as planar deformation features (PDFs), as well as micro-twins (impact indicators), which are only ever produced by large-scale meteorite impacts.

“This research is the first to report the presence of PDFs and micro-twins in lunar zircon, which provide unequivocal evidence of the immense pressures that occur during an impact event,” Dr. Timms said.

“This research also provides a new explanation of how these features form. As shock waves pass through a rock, fractions of a second after a meteorite impact, these features form like microscopic crumple zones which are caused by directional differences in zircon’s elasticity.”

Dr. Timms said the research, which characterises the impact shock features, would provide a new framework for scientists to interpret impact-related data.

“The new conceptual framework allows lunar scientists to recognise whether complex zircon grains can be explained by a single impact event, or require more than one impact event,” he said.

“Furthermore, our new approach allows us to recognise impact-related features in zircon in lunar and terrestrial rocks that would otherwise be overlooked or difficult to find.

“This helps us to overcome one of the major problems with studying the impact history of the Earth, as direct evidence of impacts, such as craters, become eroded and destroyed through processes of plate tectonics, so much so that none are preserved from the earliest periods of the Earth’s history.”

Dr. Timms said the research was a step closer to the major scientific goal of establishing the absolute timing of meteorite impact events on the Moon, and consequently, the inner solar system.

“The current paradigm for the early impact history of our solar system stems from studies of lunar rocks and involves a period of intense impact events around 3.9 billion years ago, known as the ‘Late Heavy Bombardment’,” he said.

“Recent dating of grains of the mineral zircon in lunar samples by the research group at Curtin shows a range of ages that challenges this view and we anticipate the new framework will help us to test if this bombardment is recorded in similar age zircon grains on Earth.”

This research was the result of a collaborative effort between the Curtin research group in Applied Geology, Dr. Nick Timms, Professor Steven Reddy, Associate Professor Alexander Nemchin, Dr. Marion Grange and Professor Bob Pidgeon, as well as Dr. Rob Hart from the Materials Characterisation Group in Curtin Applied Physics and Dr. Dave Healy at the University of Aberdeen, UK.

The Curtin research group in Applied Geology is a pioneer in its field and is currently leading the world in the application of quantitative microstructural techniques to zircon research. In 2006, they also made the discovery that zircon could deform in the Earth’s crust and that the structures formed in this deformation could help modify the geochemistry of zircon.

The group’s most recent paper, Resolution of impact-related microstructures in lunar zircon: A shock deformation mechanism map, is published in the internationally esteemed journal, Meteoritics and Planetary Science.

Explore further: Zircon remnants trace planetary evolution

Related Stories

Australian researcher discovers giant asteroid impact

October 24, 2010

( -- A geothermal energy researcher from the University of Queensland (UQ) has found evidence of a major asteroid impact that occurred more than 300 million years ago in the South Australian outback.

New hypothesis on crater debris

September 27, 2011

A team of researchers partnered with the NASA Lunar Science Institute (NLSI) has developed a new hypothesis for the origin of crater ejecta—debris that is launched out of a crater during meteorite impacts.

New research casts doubt on the late heavy bombardment

January 6, 2012

Was the early solar system bombarded with lots of big impacts? This is a question that has puzzled scientists for over 35 years. And it’s not just an academic one. We know from rocks on Earth that life began to evolve ...

Recommended for you

Earth might have hairy dark matter

November 23, 2015

The solar system might be a lot hairier than we thought. A new study publishing this week in the Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory, Pasadena, California, proposes the existence of ...

The hottest white dwarf in the Galaxy

November 25, 2015

Astronomers at the Universities of Tübingen and Potsdam have identified the hottest white dwarf ever discovered in our Galaxy. With a temperature of 250,000 degrees Celsius, this dying star at the outskirts of the Milky ...

Scientists detect stellar streams around Magellanic Clouds

November 23, 2015

(—Astronomers from the University of Cambridge, U.K., have detected a number of narrow streams and diffuse debris clouds around two nearby irregular dwarf galaxies called the Magellanic Clouds. The research also ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (3) Jan 24, 2012
... revealing indisputable proof of meteorite collisions on the Moon.

The craters didn't do that for ya? Use some better wording here...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.