Posted on 10/17/2005 7:33:37 PM PDT by NormsRevenge
WASHINGTON (AFP) - A first-ever high-resolution map of Mars' entire magnetic field provides new evidence that Earth-like plate tectonics - great crustal plates pulling apart and crashing together - underpin the Red Planet's surface geology, US space agency NASA said.
Using the map made by the National Aeronautic and Space Administration's Mars Global Surveyor spacecraft, scientists were able to detect signs of transform faults, which are tell-tale indications of plate tectonics on Earth.
The results of the scientists' research appeared in the October 10 edition of the journal Proceedings of the National Academy of Sciences.
Evidence of plate tectonics at work below Mars' surface was seen in magnetic field "striping" mapped by the Mars Global Surveyor while it orbited the planet over four years, according to the scientists at the NASA Goddard Space Flight Center in Maryland.
Such stripes, which represent magnetic fields pointed in positive or negative directions, are formed when two tectonic plates are pushed apart by molten rock coming up from the mantle, they said.
Similar magnetic stripes show up, for instance, on the Earth's Mid-Atlantic Ridge, which was formed by this type of tectonic activity.
Based on the new map, the scientists concluded that Mars too had regions where new crust came up from the mantle and spread across the surface, forcing other crustal areas back down.
"The new map shows evidence of features, transform faults, that are a tell-tale of plate tectonics on Earth," said Norman Ness of the University of Delaware.
According to Jack Connerney of the Goddard center, plate tectonics provides an overarching theory for a number of the features of the Martian landscape.
It can explain the positioning of the Tharsis volcanoes, which lie in a straight line. The volcanoes may have formed from the motion of a crustal plate over a fixed hotspot in the mantle below, just as the Hawaiian islands were thought to have formed, according to Connerney.
In addition, the massive Valles Marineris canyon, six times as long and eight times as deep as the Grand Canyon in the United States, looks just like the result of tectonic plates pulling apart.
The magnetic striping associated with the Valles Marineris on the new Mars map provides further evidence of this.
"The more measurements we obtain, the more accuracy, and spatial resolution we achieve" to support the theory, said Connerney.
This image captured by NASA's Earth-orbiting Hubble Space Telescope shows Mars when it was approximately 43 million miles (68 million km) from Earth. A first-ever high-resolution map of Mars' entire magnetic field provides new evidence that Earth-like plate tectonics - great crustal plates pulling apart and crashing together - underpin the Red Planet's surface geology, US space agency NASA said.(AFP/NASA/File)
Those who are not familiar with geophysics probably do not know the significance of this statement. Here on the Earth, where the magnetic field flips roughly every quarter of a million years, any magma or lava that solidifies will be aligned with the magnetic field at the time of solidification. It will not change its alignment unless it receives a physical shock or it melts. This is significant because geophysicists can go out in boats and measure the magnetic field alignment of these rocks. If you do it near a mid-ocean trench, you can calculate how fast the plates have been moving apart for millions of years. It is also one of the strong pieces of evidence that helped confirm the plate tectonics theory.
This is very significant on Mars, and makes it very likely that if we get ground crews on Mars, we can determine the geological history of the planet until the planetary magnetic field failed. We could know more about the early geology of Mars than we do know about the early geology of the Earth (since plate tectonics recycles plates roughly every 250 million years, it is hard to find geological evidence older than that--though it exists in certain places). This is a big plus for all of the planetary scientists out there.
Al Wegener the prophet.
Well then, how did/does Olympus Mons keep cooking as the largest volcano in the Solar System?
The track of the Hawaiian plume heads NW, towards Kamchatka, not Australia, and the first seamounts of it have been subducted below Asia already.
Wow. I had thought that Earth was (so far) the only planet that exhibited tectonics.
Anyone know if Venus has been proven to have tectonics? I know they have continents, and it seems that one implies the other.
Mars is just to tempting not to go there, thus to answer this...and a million other questions.
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