On Earth, lava flows
react rapidly with oxygen and other elements in the atmosphere, changing their composition.
Eventually, the ancient lava flows
ended up high on the ridge tops.
We might expect to see the vents or openings from which the lavas flowed, and the characteristic edges and lobes seen on lava flows
on Earth and Mars, but most of the lunar maria are about 3.5 billion years old and have experienced eons of bombardment by small meteorites.
As described in last month's column, often it's millions of years of impacts that cause so much deterioration, but for craters associated with maria, lava flows
are an added force of aging.
The new result came out of research into possible interactions of lava flows
and floods of water in the Elysium volcanic province of Mars.
The Philippine Institute of Volcanology and Seismology (Phivolcs) said Mayon Volcano has exhibited sporadic and weak lava fountaining, lava flow
and degassing from the summit crater in the past 24 hours.
The experts explained that because of the lava flows
, volcanism could have played a huge role in creating the brain-like feature.
In particular, why do the lavas pile up to construct a symmetrical shield rather than flowing downhill as long lava flows
? The answer probably relates to the slope of the terrain where the volcano forms and how much lava is actually erupted.
"These autonomous underwater vehicle-generated maps allowed us, for the first time, to comprehensively map the thickness and extent of lava flows
from a deep-ocean submarine in high resolution," David Caress, an MBARI engineer and lead author on one of the Nature Geoscience articles, said.
That produced a type of rock called komatiite, which are "basically superhot versions of Hawaiian-style lava flows
," study leader and Virginia Tech professor Esteban Gazel said.
Previous lava flows
from Kilauea destroyed more than 180 homes between 1983 and 1990, but until this week no dwellings had been lost to the volcano since 2012.
By contrast, a segment at 25 [degrees] N was flooded not long ago by smooth lava flows
that are topped by a variety of small, more recently erupted features.