The moon once had way more water than we ever imagined, lunar meteorite reveals

[Admin]

A new examination of a lunar meteorite revealed a mineral that could change our understanding of water on the moon, showing its crust was water-rich around 4 billion years ago.

The moon once had way more water than we ever imagined, lunar meteorite reveals : Read more

 

[Cdr. Shepard]

Timeline is difficult to follow, as there are several references to the crust drying out thousands of years ago, millions of years ago, and alternately, billions of years ago.

As far as I can tell, the events referenced pertained to the earliest periods in the lunar geological timescale, ~4.0-4.5B years ago. The reference to recent events occurring on the order of mere thousands of years ago confuses me. I can't find anything regarding significant lunar geological changes occurring, including loss of water/volatiles, in the past few million years.

 

[Wolfshadw]

Makes sense if the Moon was orbiting around the Earth at the time of the Late Heavy Bombardment. It probably would have collected a significant amount of water from that, just as the Earth did (theoretically).

-Wolf sends

 

[Torbjorn Larsson]

From the paper supplement:

The relatively high H2O abundance (~ 2300ppm) is greater than observed in Apollo highlands apatite grains (~ 20–1800 ppm H2O).

 

[rod]

I was glad to see this pointed out in the space.com article,
"Hayden focused primarily on the mineral apatite, which contains volatiles in its mineral structure, finding it within "ferroan anorthosites" in the sample. Ferroan anorthosites are the only known lunar rocks that formed directly from the Lunar Magma Ocean, a slushy sea of molten rock that existed on the surface of the moon 4.5 million to 4.3 million years ago. Finding this volatile-rich element in the ferroan anorthosite indicates water was present in the moon's mostly molten stages and allowed researchers to study this stage of the moon's evolution directly, the first time this had been done."

The lunar magma ocean on the Moon postulated after the giant impact with Theia raises questions in my mind about how wet the Moon could be

Moon's crust may have formed from 'slushy' magma ocean long ago

The faster-solidifying top portion of this ocean became the lunar crust, a new study suggests.

www.space.com

“The moon's crust might have formed from an unevenly layered "slush" of magma that once covered the entire body, a new study reports. It's the latest turn of the wheel on scientists' picture of how the moon and its features formed, a picture that's been continually changing ever since Apollo astronauts brought moon rocks back to Earth in the late 1960s and early 1970s..."

Reference paper, Formation of the Lunar Primary Crust From a Long-Lived Slushy Magma Ocean, https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL095408, 13-Jan-2022.

“Abstract Classical fractional crystallization scenarios of early lunar evolution suggest crustal formation by the flotation of light anorthite minerals from a liquid magma ocean. However, this model is challenged by the > 200 Myr age range of primitive ferroan anorthosites, their concordance with Mg-suite magmatism and by the compositional diversity observed in lunar anorthosites. Here, we propose a new model of slushy magma ocean crystallization in which crystals remain suspended in the lunar interior and crust formation only begins once a critical crystal content is reached. Thereafter crustal formation occurs by buoyant melt extraction and magmatism..."