Paris: Japanese astronomers on Sunday said
they had found traces of a mineral that adds an important
piece of knowledge to the puzzle of the Moon`s geological
past.
Using a instrument-laden probe, Kaguya, which was
placed in orbit around the Moon in 2007, the team found
abundant signatures of the mineral in concentric rings in
three big crater regions.
The mineral, called olivine, is deemed to be a
telltale of mantle, the deep inner layer of iron- and
magnesium-rich rock that lies beneath the Moon`s crust.
A leading theory is that the Moon was created about
4.5 billion years ago after the "Big Whack" -- it was ripped
from Earth after our planet suffered a gigantic collision from
some space object.
As the material coalesced into a ball, its surface
gradually cooled, forming a crust made of a light-coloured
aluminous mineral, feldspar, which floated in a dense, molten
liquid.
Kaguya`s data add a chapter to this "lunar magma
ocean" hypothesis.
It suggests that after the crust had formed, there
was some massive overturn in the fiery liquid beneath.
Olivine-rich mantle was brought from deep within the lunar
bowels to within the base of the crust.
At the craters sampled by the probe -- the South
Pole-Aitken, Imbrium and Moscoviense impact basins -- the
Moon`s crust is very thin, and the olivine mantle may have
been exposed by asteroids that smashed into the lunar surface,
the paper suggests.
PTI
