Chinese Moon Rover Yutu Finds New Moon Rocks in Purple Palace Crater

Summary: Chinese moon rover Yutu discovers new moon rocks, with interesting concentration levels, in Purple Palace crater, officially named Zi Wei crater.

Figure 1: Location of the Chang'e-3 landing site ~ (a) Chang'e-1 CCD image with boundaries of typical mare basalt units. (b) Chang'e-2 CCD image and (c) LROC NAC image (LROC NAC M1142582775R). (d) The traverse map of the Yutu rover and the locations of APXS and VNIS measurements. (e) Panoramic view of the ‘Zi Wei’ crater by the Panoramic Camera on the Yutu rover at the CE3-0008 site: Zongcheng Ling et al., CC BY 4.0, via Nature Communications

Earth’s moon becomes more interesting with new moon rocks discovered by Chinese moon rover Yutu in Zi Wei crater, nicknamed Purple Palace, after landing in the moon’s northern hemisphere on Dec. 14, 2013, according to findings published online Dec. 22, 2015, in Nature Communications.

Yutu's landing site in the northern part of the lava-rich Imbrium Basin is ideally located near a relatively young lava-flow crater, nicknamed Purple Palace and officially named Zi Wei crater. The crater's loose surface materials, known as regolith, form a thin layer that is undisturbed by debris from other lunar sites. The purity of Zi Wei's regolith reveals the composition of the crater's underlying volcanic bedrock.

An analysis of Yutu’s 32 days of surface operations by the study’s 17 researchers identifies mineral concentrations in the crater’s basalts, which are dark, fine-grained, volcanically-formed rocks. Concentrations differ from levels in samples collected in the 1970s by NASA’s Apollo astronauts and the former Soviet Union’s Luna probes.

Yutu’s Active Particle-Induced X-ray Spectrometer (APXS) and Visible and Near-Infrared Imaging Spectrometer (VNIS) register extremely high concentrations of calcium oxide, rich levels of iron oxide and intermediate concentrations of titanium dioxide. Apollo and Luna samples yield only extreme levels, either very high or very low, of titanium dioxide. Apollo and Luna samples link to the moon’s peak volcanism of 3 to 4 billion years ago. Yutu’s data for new moon rocks concern more recent lava flows from 3 billion years ago or less.

“We now have ‘ground truth’ for our remote sensing, a well-characterized sample in a key location,” says co-author Bradley L. Jolliff, the Scott Rudolph Professor of Earth and Planetary Sciences at Washington University in St. Louis. “We see the same signal from orbit in other places, so we now know that those other places probably have similar basalts.”

With its predictable occurrence in igneous, or volcanic, rocks, titanium is a key indicator to understanding the moon’s volcanic history. Titanium’s varying concentrations in weight from less than 1 percent to over 15 percent reveal differences in mantle source regions deriving from the cooling of the moon’s supposed early magma ocean.

Titanium’s occurrences in ilmenite (FeTiO3) around Yutu’s landing site reflect the area’s relative youthfulness. Ilmenite crystallizes at a late stage in volcanic activity, with only about 5 percent of the original magma melt left.

Yutu’s exploration covers 374 feet ( 114 meters) of the young crater. Zi Wei has a diameter of about 1,476 feet (450 meters).

Yutu’s journey to the moon occurs during the Chang’e 3 mission launched by the China National Space Administration as the second phase of the three-phase Chinese Lunar Exploration Program. Chang’e 3 mission objectives include a soft landing and exploration of the moon’s surface topography. The mission’s name honors the Chinese goddess of the moon, originally known as Heng’e.

China’s first lunar rover receives its name from an online poll. Yutu literally means “Jade Rabbit.” The rover’s name honors the moon goddess’s mythological rabbit, known also during China’s golden age Han dynasty (206 BCE to 220 CE) as Gold Rabbit.

Yutu's discovery of new moon rocks sheds new light on Earth's moon. The distinct mineral profile of Chang'e 3's landing site's new moon rocks aids in understanding the processes involved in the moon's formation.

“The diversity tells us that the Moon’s upper mantle is much less uniform in composition than Earth’s,” co-author Bradley L. Jolliff explains. “And correlating chemistry with age, we can see how the Moon’s volcanism changed over time.”

Yutu rover's discovery occurred in Purple Palace crater, officially named Zi Wei crater: Guardian Science @guardianscience via Twitter Dec. 22, 2015

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Chang'e landing site: Zongcheng Ling et al., CC BY 4.0, via Nature Communications @ http://www.nature.com/ncomms/2015/151222/ncomms9880/fig_tab/ncomms9880_F1.html

Yutu rover's discovery occurred in Purple Palace crater, officially named Zi Wei crater: Guardian Science‏ @guardianscience via Twitter Dec. 22, 2015, @ https://twitter.com/guardianscience/status/679331856228028416

For further information:

Guardian Science‏ @guardianscience. "New type of moon rock discovered by Chinese lunar lander." Twitter. Dec. 22, 2015.
Available @ https://twitter.com/guardianscience/status/679331856228028416

Ling, Zongcheng, et al. "Correlated compositional and mineralogical investigations at the Chang'e landing site." Nature Communications, vol. 6 (Dec. 22, 2015): article 8880. DOI: 10.1038/ncomms9880
Available @ http://www.nature.com/ncomms/2015/151222/ncomms9880/full/ncomms9880.html

Lutz, Diana. "Chinese rover analyzes Moon rocks: First new 'ground truth' in 40 years." Washington University in St. Louis The Source > Newsroom. Dec. 22, 2015.
Available @ https://news.wustl.edu/news/Pages/Chinese-rover.aspx

Marriner, Derdriu. "Deciphering the Moon via Unusual Basaltic Data Beamed by a Jade Rabbit." Earth and Space News. Monday, Dec. 28, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/12/deciphering-moon-via-unusual-basaltic.html

wochit News. "Chinese Rover Discovers New Moon Rock." YouTube. Dec. 22, 2015.
Available @ http://www.youtube.com/watch?v=DdjAdaOS3Ow