The Venus Lithosphere

Like the Earth's lithosphere, the lithosphere of Venus is the not-so-rigid part of the crust of Venus which is cooler than the interior of Venus, somewhat like the film on top of a cup of hot cocoa. Unlike the Earth, the lithosphere of Venus may be too thick to move.

On E arth, the lithosphere can be pushed aside in response to the warmth of the Earth. 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.

The shape of the volcanoes suggests that in its history, Venus, like Mars, has built a thick lithosphere. A thick lithosphere supresses the motions of plates over a surface, even though the interior of the planet is warm enough for churning motions which cause material to rise from the deep interior.

Why would Venus, and not the Earth, have a thick lithosphere? The answer is that unlike the Earth, the rocky material which comprises the lithosphere of Venus does not contain enough trapped water to allow the lithosphere to deform and subduct. Thus the lithosphere cannot make way for hot, rising magma from the interior and instead stays in place and thickens by cooling gradually.

Nevertheless, on Venus, there may be mechanisms for the surface to turn over.


There is no subduction of the crust of Venus.
Click on image for full size version (40K GIF)

What about lithospheric motions on Earth?


The Crust of Venus

Unlike the Earth's crust, the crust of Venus is very rigid. On Earth, the lithosphere can be pushed aside in response to the warmth of the Earth. The crust then subducts, melts, and becomes part of the warm rising magma again. Thus on Earth, the recycling of the crust keeps the crust from becoming too thick.

The shape of the volcanoes suggests that over its history, Venus, like Mars, has built a thick crust. A thick crust prevents motions of p lates over a surface.

Why would Venus, and not the Earth, have a thick crust? The answer is that unlike the Earth, the rocky material which comprises the crust of Venus does not contain enough trapped water to allow the rocky material to bend and deform (like silly putty). Thus the crust stays in place and thickens by cooling gradually.

Nevertheless, on Venus, there may be mechanisms for the surface to turn over.


There is no subduction of the crust of Venus.
Click on image for full size version (40K GIF)

What about lithospheric motions on Earth?


The Crust of Venus

Unlike the Earth's crust, the crust of Venus is very rigid.

The shape of the volcanoes suggests that over its history, Venus, like Mars, has built a thick crust. A thick crust prevents motions of a surface.

Why would Venus, and not the Earth, have a thick crust? The answer is that unlike the Earth, the rocky material which comprises the crust of Venus does not contain enough trapped water to allow the rocky material to bend and deform (like silly putty). Thus the crust stays in place and thickens by cooling gradually.

Nevertheless, on Venus, there may be mechanisms for the surface to turn over.


There is no subduction of the crust of Venus.
Click on image for full size version (40K GIF)

What about lithospheric motions on Earth?




The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). ©1995-1999, 2000 The Regents of the University of Michigan; ©2000-01 University Corporation for Atmospheric Research. All Rights Reserved. Site policies and disclaimer