This is an image of some Martian volcanoes.
Click on image for full size
Image from: NASA
The Martian Lithosphere
Like the Earth's lithosphere, the Martian lithosphere is the not-so-rigid part of the crust of Mars which is cooler than the interior of Mars somewhat like the film on top of a cup of hot cocoa. On Earth, the lithosphere can be pushed in response to the warmth of the Earth. Warm magma rises to the very surface and pushes the cooler, rocky lithosphere aside. The lithosphere then subducts, melts, and becomes part of the warm rising magma again. Thus on Earth, the recycling of the lithosphere keeps the lithosphere from becoming too thick.
Unlike the Earth, the rocky material which comprises the lithosphere of Mars does not contain enough trapped water to allow the rocky material to slide against each other. Since portions of the rocky material cannot slide against each other, the lithosphere cannot make way for hot, rising magma from the interior of Mars. Thus the lithosphere stays in place and thickens by cooling gradually. So it is that Mars does not have plates moving on the surface.
You might also be interested in:
Crust, the upper layer of the Earth, is not always the same. Crust under the oceans, called oceanic crust, is much thinner than continental crust. It is only about 5 km thick while continental crust can...more
On this map of Mars, the lightly cratered Tharsis Ridge is shown, as well as the heavily cratered Martian highlands (near the bottom of the picture), and Valles Marineris to the right. The volcanoes are...more
The unusual global geography of Mars helps to explain the fact that water has been drawn from the southern hemisphere to the northern hemisphere of the planet through all of Martian history (that is, from...more
The Martian geography is one of high altitudes at high southern latitudes and low altitudes at low latitudes. The ground is less frozen at low latitudes because it is warmer and water can evaporate. Thus,...more
Separate from the Martian outflow channels, or the river valley networks, are large Martian lakes (600 km, or ~1000 miles across) which exhibit evidence of a periodic and catastrophic release of water...more
This is an image of fog in a Martian canyon. The presence of fog provides evidence of water, and a water cycle on Mars. More fog has been seen in images returned by Mars Global Surveyor of the south polar...more
The Martian climate is more influenced by the shape of the Martian orbit than the climate of the Earth is influenced by the shape of the Earth's orbit. The orbit of Mars is more elliptical than that of...more
This is an image of a storm moving across the Martian terrain. The camera is looking down upon the storm and the storm front forms a spiral pattern, the same way terrestrial storms are presented on the...more