TECTONIC ACTIVITY
The most massive Terrestrial planets, Earth and Venus,
are likely to show
active geologies.
Mars may show geological activity.
Mercury and
the Moon are probably dead from a geological standpoint. The sorts of
geology we
expect are volcanism and tectonic activity, both
manifestations of the
fact that the interiors of the planets are hot.
A consequnce of
geological activity (and wind and water erosion on the
Earth)
is to produce a relatively young surface. (By young, we mean
that the surface features
were formed recently.) The surface of
Venus is around 300 - 800 million years old, while the majority of the Earth's
surface features are much younger. For example,
- Ocean basins are < couple hundred million years old
- Hawaiian Islands
~ millions of years old
- Grand Canyon (cut by the Colorado River) < 10 million years old
- Himalayas, Andes < tens of millions of years old
These ages are to be compared to the ages of the planets and Solar System
of 4.6 billion years.
- PLATE TECTONICS
- TECTONIC ACTIVITY ON OTHER PLANETS?