I do not think we can call it
plate tectonics at all. The crust is
surely stressed for any number of natural reasons and this is ultimately
expressed as fault movement. In this
case the movement is even aged back to the early history of Mars. Otherwise it is nice to discover fault
movement at all. It may even reveal some
geology.
Plate tectonics generates
differentiation of rock types which appears missing on Mars.
What makes images of apparent
volcanoes on Mars odd is their apparent uniformity and symmetry. This can only be possible if they are all
cinder cones. This implies a long
history of out gassing on Mars that most likely brought a lot of water and CO2
to the surface.
I also note in the image I just
dug up of Olympus Mons that a string of three additional volcanoes lie along
side that appear well spaced. This is
too good to be true and will beg a proper explanation. There has to be at least another fault controlling
their location. Better still, show me
were on Earth this is replicated.
UCLA scientist discovers plate tectonics on Mars
by Stuart Wolpert UCLA News
View of central segment of Mars' Valles Marineris.
For years, many scientists had thought that plate tectonics existed
nowhere in our solarsystem but
on Earth. Now, a UCLA scientist has discovered that the geological phenomenon,
which involves the movement of huge crustal plates beneath a planet'ssurface,
also exists on Mars.
"Mars is at a primitive stage of plate tectonics. It gives us a
glimpse of how the early Earth may have looked and may help us understand how
plate tectonics began on Earth," said An Yin, a UCLA professor of Earth
and space sciencesand
the sole author of the new research.
Yin made the discovery during his analysis of satellite images from
THEMIS ThermalEmission Imaging System, an instrument on board the MarsOdyssey spacecraft,
and from the HIRISE (High Resolution Imaging Science Experiment)
camera on NASA's Mars Reconnaissance Orbiter.
He analyzed about 100 satellite images - approximately a dozen were
revealing of plate tectonics.
Yin has conducted geologic research in the Himalayas and Tibet ,
where two of the Earth's seven major plates divide.
"When I studied the satellite images from Mars, many of the
features looked very much like fault systems I have seen in the Himalayas and
Tibet, and in California as well, including the geomorphology," said Yin,
a planetary geologist.
For example, he saw a very smooth, flat side of a canyon wall, which
can be generated only by a fault, and a steep cliff, comparable to cliffs in California 's Death Valley ,
which also are generated by a fault. Mars has a linear volcanic zone, which Yin
said is a typical product of plate tectonics.
"You don't see these features anywhere else on other planets in
our solar system, other than Earth and Mars," said Yin, whose research is
featured as the cover story in the August issue of the journal Lithosphere.
The surface of Mars contains the longest and deepest system of canyons
in our solar system, known as Valles Marineris (Latin
for Mariner Valleys and named for the Mariner 9 Mars orbiter of
1971-72, which discovered it). It is nearly 2,500 miles long - about nine times
longer than the Earth's Grand Canyon .
Scientists have wondered for four decades how it formed. Was it a big crack in
Mars' shell that opened up?
"In the beginning, I did not expect plate tectonics, but the more
I studied it, the more I realized Mars is so different from what other
scientists anticipated," Yin said. "I saw that the idea that it is
just a big crack that opened up is incorrect. It is really a plate boundary,
with horizontal motion. That is kind of shocking, but the evidence is quite
clear.
"The shell is broken and is moving horizontally over a long
distance. It is very similar to the Earth's Dead Sea
fault system, which has also opened up and is moving horizontally."
The two plates divided by Mars' Valles Marineris have moved
approximately 93 miles horizontally relative to each other, Yin said.
California's San Andreas Fault, which is over the intersection of two plates,
has moved about twice as much - but the Earth is about twice the size of Mars,
so Yin said they are comparable.
Yin, whose research is partly funded by the National Science Foundation,
calls the two plates on Mars the Valles Marineris North and the Valles
Marineris South.
"Earth has a very broken 'egg shell,' so its surface has many
plates; Mars' is slightly broken and may be on the way to becoming very broken,
except its pace is very slow due to its small size and, thus, less thermal
energy to drive it," Yin said. "This may be the reason Mars has fewer
plates than on Earth."
Mars has landslides, and Yin said a fault is shifting the landslides,
moving them from their source.
Does Yin think there are Mars-quakes?
"I think so," he said. "I think the fault is probably
still active, but not every day. It wakes up every once in a while, over a very
long duration - perhaps every million years or more."
Yin is very confident in his findings, but mysteries remain, he said,
including how far beneath the surface the plates are located.
"I don't quite understand why the plates are moving with such a
large magnitude or what the rate of movement is; maybe Mars has a different
form of plate tectonics," Yin said. "The rate is much slower than on
Earth."
The Earth has a broken shell with seven major plates; pieces of the
shell move, and one plate may move over another. Yin is doubtful that Mars has
more than two plates.
"We have been able to identify only the two plates," he said.
"For the other areas on Mars, I think the chances are very, very small. I
don't see any other major crack."
Did the movement of Valles Marineris North and Valles Marineris South
create the enormous canyons on Mars? What led to the creation of plate
tectonics on Earth?
Yin, who will continue to study plate tectonics on Mars, will answer
those questions in a follow-up paper that he also plans to publish in the
journal Lithosphere.
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