This is an example of Venus volcanism.
Click on image for full size
NASA/JPL
Volcanic Rises
Volcanic rises are thought to form when a portion of the deep mantle is
heated to several hundred degrees hotter than its surroundings. This portion
of the mantle is now less dense than its surroundings and begins to rise.
Such a rising bubble of material is often called a mantle plume.
As it nears
the surface, the plume may take on a mushroom-like shape, as shown in the above
sketch. It also begins to generate magma (deep inside the planet the pressure was too great to allow the material to melt)
some of which escapes to the surface to form volcanos and lava flows. In
addition, the buoyant plume pushes the surface upward, forming a
rise, and possibly contributing to the formation of rift valleys. This form of plume volcanism is similar in many ways to terrestrial plume volcanism.
There are three particular types of volcanic rises:
-
Rift-Dominated Rises
-
These are rises that contain two or more deep rift valleys. These
valleys cut through most of the rise itself, but also extend several
hundred kilometers beyond the rise itself. Atla Regio and Beta Regio
are rift-dominated rises.
- Volcano-Dominated Rises
-
These rises lack deep rift valleys. They do contain one or more large
shield volcanoes. Western Eistla Regio and Imdr Regio are
volcano-dominated rises.
- Corona-Dominated Rises
-
These rises lack large rift valleys, like volcano-dominated rises. But
instead of being dominated by shield volcanoes, their surfaces are
dominated by coronae. Corona-dominated rises include Eastern Eistla
Regio and Themis Regio.
Shop Windows to the Universe Science Store!
Our
online store includes
issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, as well as
books on science education!
You might also be interested in:
The Hawaiian Islands are an example of the way some volcanoes are made. A rising hot plume of material makes it's way to the lithosphere of the Earth from the deep interior, and erupts material unto the
...more
AU stands for Astronomical Units. Distances in space are too large to measure in Earth standards like miles or kilometers. For distances too large to measue in AU, we use light years. A light year is the
...more
The solar wind is formed as the Sun's topmost layer blows off into space carrying with it magnetic fields still attached to the Sun. Gusts and disturbances form in the solar wind associated with violent
...more
For a planet to be affected by a blob of material being ejected by the sun, the planet must be in the path of the blob, as shown in this picture. The Earth and its magnetosphere are shown in the bottom
...more
The aurora we are most familiar with is the polar aurora. This is what people are referring to when they speak of the northern or southern lights. But there are other less-known auroral activity, such
...more
This figure shows the effect of the aurora on the atmosphere. When FAC's enter the atmosphere and create the aurora, they warm the atmosphere impulsively. This impulse travels throughout the atmosphere
...more
This picture illustrates the streaming of particles into and out of the auroral zone, as Field-aligned currents (FAC's) short-circuit through the ionosphere. Some of the particles entering the auroral
...more
