Chinese Lunar Rover May Have Identified Mantle Exposure

Guest geological note by David Middleton

Chang’e-4: Chinese rover ‘confirms’ Moon crater theory
By Paul Rincon
Science editor, BBC News website

15 May 2019


The Chinese Chang’e-4 rover may have confirmed a longstanding idea about the origin of a vast crater on the Moon’s far side.

The rover’s landing site lies within a vast impact depression created by an asteroid strike billions of years ago.

Now, mission scientists have found evidence that impact was so powerful it punched through the Moon’s crust and into the layer below called the mantle.

Chang’e-4 has identified what appear to be mantle rocks on the surface.
It’s something the rover was sent to the far side to find out.

Chunlai Li, from the Chinese Academy of Sciences in Beijing, and colleagues have presented their findings in the journal Nature.

[…]

The rover landed inside a 180km-wide impact bowl called Von Kármán crater. But that smaller crater lies within the 2,300km-wide South Pole Aitken (SPA) Basin, which covers nearly a quarter of the Moon’s circumference.

[…]

Early results from the rover’s Visible and Near Infrared Spectrometer (VNIS) suggest the rocks contain minerals known as low-calcium (ortho)pyroxene and olivine.

They fit the profile of rocks from the lunar mantle and suggest that the ancient impact that created the SPA drove right through the 50km-deep crust into the mantle.

[…]

The Beeb

The Lunar and Planetary Institute’s South Pole – Aitken Basin Landing Site Database has a pretty cool interactive mapping tool for the South Pole – Aitken Basin…

In other Lunar geology news…

The Moon appears to have active, relatively young, thrust fault systems.


The moon is still geologically active, study suggests
May 13, 2019 


We tend to think of the moon as the archetypal “dead” world. Not only is there no life, almost all its volcanic activity died out billions of years ago. Even the youngest lunar lava is old enough to have become scarred by numerous impact craters that have been collected over the aeons as cosmic debris crashed into the ground.

Hints that the moon is not quite geologically dead though have been around since the Apollo era, 50 years ago. Apollo missions 12, 14, 15 and 16 left working “moonquake detectors” (seismometers) on the lunar surface. These transmitted recorded data to Earth until 1977, showing vibrations caused by internal “moonquakes”. But no one was sure whether any of these were associated with actual moving faults breaking the surface of the moon or purely internal movements that could also cause tremors. Now a new study, published in Nature Geoscience, suggests the moon may indeed have active faults today.

Another clue that something is still going on at the moon came in 1972 when Apollo 17 astronauts Gene Cernan and Jack Schmitt inspected a step in the terrain, a few tens of metres high, that they called “the Lee-Lincoln scarp”. They, and their team of advisers back on Earth thought it might be a geological fault (where one tract of crustal rock has moved relative to another), but they weren’t sure.

[…]

It is now widely agreed that these are thrust faults, caused as the moon cools down from its hot birth. As it does, “thermal contraction” causes its volume to shrink and compresses the surface. That means that the moon is shrinking slightly. However, thrust faults don’t necessarily have to be active and moving, causing more further tremors. The same thing has been happening on Mercury on a far grander scale, where the planetary radius has shrunk by 7km during the past 3m years. There, the biggest scarps are nearly a hundred times larger than those on the moon.

Active faults
Analysis shows that these faults are relatively young, not older than about 50m years. But are they active and still moving today? In the new study, Tom Watters of the Smithsonian Institution in the US and colleagues employed a new way to pinpoint the locations of the near-surface moonquakes in the Apollo data more precisely than was previously possible.

The team discovered that of the 28 detected shallow quakes, eight are close to (within 30km of) fault scarps, suggesting these faults may indeed be active. 

[…]

The Conversation

To capitalize, or not to capitalize

Capitalize the names of planets (e.g., “Earth,” “Mars,” “Jupiter”). Capitalize “Moon” when referring to Earth’s Moon; otherwise, lowercase “moon” (e.g., “The Moon orbits Earth,” “Jupiter’s moons”). Capitalize “Sun” when referring to our Sun but not to other suns. Do not capitalize “solar system” and “universe.” Another note on usage: “Earth,” when used as the name of the planet, is not preceded by “the”; you would not say “the Neptune” or “the Venus.” When “earth” is lowercased, it refers to soil or the ground, not the planet as a whole. Do use “the” in front of “Sun” and “Moon” as applicable. 

NASA

And… It’s NASA, not Nasa… 😉

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46 thoughts on “Chinese Lunar Rover May Have Identified Mantle Exposure

  1. Yeah…well, active faults on the Moon… Since there is little chance that the Moon retains enough heat to have a plastic-like mantle, then an “active fault” is likely no more then gravitational induced movements over a great deal of time. You get a shrinkage fault that doesn’t quite make it to the lowest energy state, and it’s ready to start collapsing bit by bit over time, giving you shallow small quakes.

    Without volume it just cannot be retaining enough heat. Without sufficient radioactive materials it cannot self-generate enough heat (the Moon is thought to be mostly made of upper Earth materials, while most radioactive materials would be deep). The orbit would supply a little energy (interaction with tides on the Earth), but nothing close to what it would need to heat rock to a plastic state.

    So active-fault…Yeah, it’s slipping down, but not because of anything like continental drift. Different principle entirely. Better to call it a gravity-fault or shrinkage fault.

    • I blame global warming and climate change, and it’s getting worse! Be very afraid!!!

      This requires more research funding – send money, lots and lots of money. Save the starving polar bears and the bouncing walruses and all dear endangered species, except of course for humanity – a scourge upon the planet – our beleaguered mother Gaia.

      Our beloved planet is burning!!! It must be true, because Bill “the-end-is-Nigh” the science guy said so!

      OMG!!! I’m so stressed I’m going to explode! I’m going to crazy-glue my private parts to a city bus! Yes! That’s the ticket – that’ll stop climate change! Yikes!!!…………… STOP THE BUS! STOP THE BUS!!!

      [Do I really have to say “sarc-off”?]

      We are governed by scoundrels and surrounded by imbeciles who believe them.

  2. Oh, and as for “NASA” versus “Nasa”…

    It’s “NASA” when they are talking about space and planets and stuff they actually understand, and “Nasa” when they speculate about climate change. They loose 3/4’s of their credibility and the letters shrink into lowercase. “nasA”, “nAsa”, and “naSa” are also acceptable spellings when they rant on climate change.

    • There’s a girl from Japan who plays on the LPGA tour and her name is Nasa Hataoka. And, yes, she was named after the space angency. Her parents liked the sound of the name.

  3. The mantle is still not where the real action is.
    The real geologist’s and planetary geophysicist’s dream though will be NASA’s mission to the metal asteroid Psyche, scheduled for a 2022 launch, with an arrival in 2026.
    https://www.space.com/40272-metal-asteroid-psyche-nasa-mission-video.html

    Scientists believe it is the remnant of a planetesimal core, shattered and exposed in an early collision. As rocky planets formed 4.5 billion years ago, the disruption from Jupiter kept the region between Mars and Jupiter a shooting gallery so that all that remains today are fragments of failed rocky planets we call the asteroid belt. We have no way of accessing the core material directly of any existing moon or planet. But Pysche offers a glimpse of the material that forms the mostly metal (iron-nickle-?) core of the inner planets.
    Psyche seems to have a surface that is 90% metallic (iron), with small amounts – 6±1% – of orthopyroxene.
    And even a “small-ish” piece of Pysche broke free and brought back to Earth at a Lagrange point or to a HEO could provide many centuries/millenia worth of raw base metals, uranium, thorium, and rare earths mineral for extraction and use on Earth.

  4. Many decades ago I red a novel where the acting persons (I think some criminals) repeatedly as a password said: Nobody saw the other side of the Moon. The rest I have forgotten.

  5. Okay…..except….It should be N.A.S.A. like the Man from U.N.C.L.E. what ever happened to the period after each letter?

    • Ask Nick Fury about that… It’s Agents of S.H.I.E.L.D. … but NASA is NASA according to NASA… Go figure. And AAPG, SEC, GCAGS, AGU, etc., all drop the periods.

      • I often wonder the same thing about U.S.A., which got reduced to US. Should it now be pronounced like us?

        SR

      • Dang it! We taxpayers paid dearly for those periods! We want ’em! We want ’em all! We want ’em now!

  6. I would have thought seismic detectors would be pretty obvious. Anyway, we have a new report of a marsquake. link

    If the moon seismic detectors died a long time ago, why didn’t they send replacements? Our knowledge of Earth’s internal structure is largely based on seismic waves. You’d think the same would apply to the Moon and Mars.

    • Interesting thought…I wonder if the natural Moon quakes are powerful enough to be used for this?

      And then there are the meteor hits…I wonder if we are detecting those as well? I wonder if that is what some of the quakes actually are?

      Anyway, it takes a great amount of energy to produce seismic quakes that are then detected from a long distance (seismic refraction) – Planet Earth quakes are powerful. On the Moon, you would likely need to be close to the source of the energy to detect anything useful. It would be a function of how well the energy travels through the medium, and how distinct the boundaries are. You would need multiple detectors measuring the same quake to make a 3-D inference of the geology.

      Very interesting thought. (tipping my hat…err…no hat so my drink!)

  7. How can the Chinese Rover be on the far side of the Moon, unless we have
    satellites circling the Moon to relay back the data from it.

    MJE VK5ELL

  8. “mission scientists have found evidence that impact was so powerful it punched through the Moon’s crust and into the layer below called the mantle.”

    “a vast impact depression created by an asteroid strike billions of years ago.”

    If that strike occurred when the moon was newly formed, the crust would have been thin, and more easily punched through than today.

  9. The moons surface spends two weeks in the sunlight and two weeks on the “dark side”. Would those extreme changes in surface temperature cause enough expansion and contraction to register as quakes?

  10. Of course there are moonquakes. I read about them in “Gentlemen Please Be Seated.”

    Who are you going to believe: NASA or The Dean of Science Fiction, Robert Heinlein?

    • Frankly, I’d expect Heinlein’s conjectures (even allowing for authorial license to make the story work) to usually be closer than whatever NASA says.

      Burn incense at the altars of Fineline (God of engineers), Zeemov (God of automation and building contractors), M’Affrey (Godess of Dragons)…

  11. We have had exceptionally clear evenings and nights here in Sydney, Australia, the moon looks amazing in the sky! The last couple of days have also been really clear and the sun very very bright low in the sky, possibly due to the recent massive CME leaving a scar 200,000kms in diameter?

  12. Has anyone had a chance to look at this :
    https://www.sciencedirect.com/science/article/pii/S0019103506002351
    Possible extra-Solar-System cause for certain lunar seismic events

    The Apollo missions emplaced a four-station seismic network on the Moon’s near side that operated from 1969 to 1977. Subsequent analyses of long-period records found about 12,500 events, including almost 8500 categorized as deep moonquakes or meteoroid impacts and 4000 that were uncategorized (Nakamura et al., 1982, Nakamura, 2003). In addition, short-period seismometers that operated between 1971 and 1977 at three stations recorded many thousands of tiny events, many of which appear to be small meteoroid impacts, and others which occur commonly near the times of lunar sunrise and sunset and are probably small moonquakes generated by temperature changes (Duennebier and Sutton, 1974a, Duennebier and Sutton, 1974b).

    A fourth, rare category of lunar seismic events (Fig. 1, Fig. 2) consists of 28 events originally called high-frequency teleseismic (HFT) events (Nakamura et al., 1974). Among these are the largest seismic events recorded on the Moon, as two had energies corresponding approximately to terrestrial earthquakes with magnitude 5 (Goins et al., 1981, Oberst, 1987).

    These papers propose a link to galactic cosmic radiation.

  13. I have a simple and cheap mission for the next spacecraft heading to the Moon: Toss out a basket full of laser corner cubes in the area of this fault, and every once in a while shine a laser from Earth towards them and let the Hubble’s wide field camera take a picture. You should be able to get centimeter position measurements on the cubes, even better relative if you relax the position measurements from a few.

  14. The Chinese have also banned all shipping from the Sea of Tranquillity – which makes me think they haven’t actually been to the moon

  15. Since the Earth is obviously affected by the gravity of the Moon, wouldn’t the Moon also be affected by the gravity of the Earth? Add to that the heating and cooling by the Sun and the changes due to the elliptical orbit of the Moon around the Earth couldn’t that be causing crust movement?

    • Greg May 17, 2019 at 12:37 pm

      Since the Earth is obviously affected by the gravity of the Moon, wouldn’t the Moon also be affected by the gravity of the Earth.
      _____________________________________________________

      Moon and Earth both rotate around their gravitational center.

      Both rotate around the gravitational center with the sun.

  16. of course. If anything, you would expect the effect of the larger mass upon the smaller to be much greater than the smaller on the larger.

  17. Don’t y’all think that ” S.H.I.E.L.D. …, U.S.A. ” spellings stem from stage coach times when templates were made of wood and “points” where always left from nailing the templates onto the inscription objects – why not give the points a “artist’s touch”.

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