Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Moon's crust underwent resurfacing after forming from magma ocean

22.11.2017

The Earth's Moon had a rough start in life. Formed from a chunk of the Earth that was lopped off during a planetary collision, it spent its early years covered by a roiling global ocean of molten magma before cooling and forming the serene surface we know today.

A research team led by The University of Texas at Austin Jackson School of Geosciences took to the lab to recreate the magmatic melt that once formed the lunar surface and uncovered new insights on how the modern moonscape came to be.


This is a moon crust formation graphic.

Credit: The University of Texas at Austin/Jackson School of Geosciences

Their study shows that the Moon's crust initially formed from rock floating to the surface of the magma ocean and cooling. However, the team also found that one of the great mysteries of the lunar body's formation - how it could develop a crust composed of just one mineral - cannot be explained by the initial crust formation and must have been the result of some secondary event.

The results were published on Nov. 21 in the Journal for Geophysical Research: Planets.

"It's fascinating to me that there could be a body as big as the Moon that was completely molten," said Nick Dygert, an assistant professor at the University of Tennessee, Knoxville who led the research while a postdoctoral researcher in the Jackson School's Department of Geological Sciences. "That we can run these simple experiments, in these tiny little capsules here on Earth and make first order predictions about how such a large body would have evolved is one of the really exciting things about mineral physics."

Dygert collaborated with Jackson School Associate Professor Jung-Fu Lin, Professor James Gardner and Ph.D. student Edward Marshall, as well as Yoshio Kono, a beamline scientist at the Geophysical Laboratory at the Carnegie Institution of Washington.

Large portions of the Moon's crust are made up of 98 percent plagioclase--a type of mineral. According to prevailing theory, which the study calls into question, the purity is due to plagioclase floating to the surface of the magma ocean over hundreds of millions of years and solidifying into the Moon's crust. This theory hinges on the magma ocean having a specific viscosity, a term related to the magma's "gooiness," that would allow plagioclase to separate from other dense minerals it crystallized with and rise to the top.

Dygert decided to test the plausibility of this theory by measuring the viscosity of lunar magma directly. The feat involved recreating the molten material in the lab by flash melting mineral powders in Moon-like proportions in a high pressure apparatus at a synchrotron facility, a machine that shoots out a concentrated beam of high energy X-rays, and then measuring the time it took for a melt-resistant sphere to sink through the magma.

"Previously, there had not been any laboratory data to support models," said Lin. "So this is really the first time we have reliable laboratory experimental results to understand how the Moon's crust and interior formed."

The experiment found that the magma melt had a very low viscosity, somewhere between that of olive oil and corn syrup at room temperature, a value that would have supported plagioclase flotation. However, it would have also led to mixing of plagioclase with the magma, a process that would trap other minerals in between the plagioclase crystals, creating an impure crust on the lunar surface. Because satellite-based investigations demonstrate that a significant portion of the crust on the Moon's surface is pure, a secondary process must have resurfaced the Moon, exposing a deeper, younger, purer layer of flotation crust. Dygert said the results support a "crustal overturn" on the lunar surface where the old mixed crust was replaced with young, buoyant, hot deposits of pure plagioclase. The older cruse could have also been eroded away by asteroids slamming into the Moon's surface.

Dygert said the study's results exemplify how small-scale experiments can lead to large-scale understanding of geological processes that build planetary bodies in our solar system and others.

"I view the Moon as a planetary lab," Dygert said. "It's so small that it cooled quickly, and there's no atmosphere or plate tectonics to wipe out the earliest processes of planetary evolution. The concepts described here could be applicable to just about any planet."

Media Contact

Monica Kortsha
mkortsha@jsg.utexas.edu
512-471-2241

 @UTAustin

http://www.utexas.edu 

Monica Kortsha | EurekAlert!

More articles from Physics and Astronomy:

nachricht Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa

nachricht Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>