Oceans of the Solar System - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 227

fig. 18. Formed perhaps 3.8 to 3.5 billion years ago, the Gale Crater on Mars
contains evidence of ancient lake deposits. In the foreground, the arm of the
Curiosity rover is 2 metres long when fully extended. In the distance is the
5.5-kilometre-high summit of Aeolis Mons, which rises in the centre of
the crater.
recently, the Curiosity rover (Fig. 18), on its way to climb the enigmatic,
5-kilometre-high Aeolis Mons in the middle of Gale Crater, has dis-
covered the certain remains—the dried-up floor—of an ancient lake,
termed Yellowknife Lake, that seems to have contained water that was
not too markedly saline and that contained elements necessary for
life, such as carbon, sulphur, nitrogen, and phosphorus. 136 So there
was water for sure, ranging from lakes to possible oceans. Where did
it come from?
On Earth today, volcanic eruptions release considerable amounts
of steam because the magma itself can contain significant amounts of
water—up to a few per cent—that is released when this molten rock
nears the surface. Could the enormous Martian volcanoes, therefore,
have been a source of water for the ancient ocean that seems once to
have been on that planet? Clues here may be found in the very few
meteorites found on Earth that show, by their chemistry, that they
must have come from Mars, 137 having been blasted off the Martian
surface by meteorites, drifted across space, and then fallen to Earth.
These meteorites are mostly basaltic, and now contain very little
water, but it had been suggested they had originally contained as
much water as do terrestrial basalts, but that their history of shock