How
about none of the above folks. We have now discovered a deep seated
zone of hot rocks that is unusual and in a suggestive locale. A more
interesting question is to determine where this phenomenon is
repeated rather than stack bad guesses on top of previous bad
guesses. This is interesting and that makes me happy.
This
is deep and we do not have a stack of overlying volcanism to tell us
it is there. As well it appears we are missing a dimension. What
this means is that a transit took place and a surprising result
showed up. We now get to wait for someone to go back and map this
occurrence.
In
short it is early days and we have a viscous hot zone not likely to
bother us for a few million years.
Giant
reservoir of magma under Ethiopia may explain how continents break
apart
In
the desert of northern Ethiopia, there's a great rift in the ground
which has long thought to have been the starting point of a new
ocean, but a recent discovery has scientists wondering if they called
that right, or if they're instead seeing a whole new kind of feature
forming.
The
Afar Rift has been called 'an
ocean in the making',
as this is where the continents of Africa and Asia are slowly
spreading apart from one another. Presumably, sometime in the future,
the continents would get far enough apart that water from the Red
Sea and Gulf
of Aden would
rush in and we would be witness to the birth of what would someday
become a new ocean. Scientists have seen similarities between the
Rift and the Mid-Atlantic
Ridge, where magma
wells up to make the ocean floor spread. However, a research team
recently discovered a massive blob of magma, measuring around 500
cubic kilometres in size, lurking deep beneath the region, and that's
unlike anything they've seen before.
When
magma rises up from deep down under mid-ocean ridges and volcanoes,
it tends to form reservoirs just beneath the surface, and these
reservoirs act to feed the activity of the ridge or volcano. The
magma doesn't stay deeper down in the mantle because it's too buoyant
— it gets forced upwards into the crust by the pressures around it.
In
the case of the magma under the Afar Rift, though, it's quite far
down, roughly 10 kilometres below the surface, and the blob is huge —
extending downward to a total depth of around 35 kilometres and it's
roughly 30 kilometres wide. Also, this apparently isn't just a recent
development, as the researchers say the volume of magma implies that
it's been there for tens of thousands of years.
Although
this new discovery has sparked a lot of discussion amongst geologists
and geophysicists, the researchers have one possible explanation for
what they're seeing.
Reservoirs
of magma that gather near the surface feed volcanoes and mid-ocean
ridges, and these tend to provide these formations with 'fuel' to
cause localized or sporadic events. A huge magma reservoir that stays
deep down in the mantle, like this one, could be what causes enough
strain to build up in the crust to actually
split continents apart.
No comments:
Post a Comment