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Basalt

In planetary science the most important group of igneous rocks are the basaltic rocks: gabbros and basalts. These two kinds of rock are both what is known as "basic".

The basaltic rocks are made up of feldspars and other minerals common in planetary crusts. They have been identified as major surface rocks on the dark lunar planes and much of Mars, Venus, and the asteroid Vesta. The lunar highlands have many gabbros (made largely of potassium feldspar - also known as plagioclase).

Granitic rock is much less common on the other terrestrial planets, a fact having to do with the fractionation - where early crystallizing minerals separate from the rest of a magma - a process that takes place uniqely on earth due to the prevelance of plate_tectonics.

The difference between granites and basalts is in silica content. A basalt is about 53% SiO2, granite 73%.


This image shows a type of igneous rock called basalt.
Click on image for full size version (92K JPG)
Image from: C. Alexander

Go to a listing of Rocks by mineral group


Basalt

In planetary science the most important group of igneous rocks are the basaltic rocks: gabbros and basalts. These two kinds of rock are both what is known as "basic".

The basaltic rocks are made up of feldspars and other minerals common in planetary crusts. They have been identified as major surface rocks on the dark lunar planes and much of Mars, Venus, and the asteroid Vesta. The lunar highlands have many gabbros (made largely of potassium feldspar - also known as plagioclase).

Granitic rock is much less common on the other terrestrial planets, a fact having to do with the fractionation - where early crystallizing minerals separate from the rest of a magma - a process that takes place uniqely on earth due to the prevelance of plate_tectonics.

The difference between granites and basalts is in silica content. A basalt is about 53% SiO2, granite 73%.


This image shows a type of igneous rock called basalt.
Click on image for full size version (92K JPG)
Image from: C. Alexander

Go to a listing of Rocks by mineral group


Basalt

In planetary science the most important group of igneous rocks are the basaltic rocks: gabbros and basalts. These two kinds of rock are both what is known as "basic".

The basaltic rocks are made up of feldspars and other minerals common in planetary crusts. They have been identified as major surface rocks on the dark lunar planes and much of Mars, Venus, and the asteroid Vesta. The lunar highlands have many gabbros (made largely of potassium feldspar - also known as plagioclase).

Granitic rock is much less common on the other terrestrial planets, a fact having to do with the fractionation - where early crystallizing minerals separate from the rest of a magma - a process that takes place uniqely on earth due to the prevelance of plate_tectonics.

The difference between granites and basalts is in silica content. A basalt is about 53% SiO2, granite 73%.


This image shows a type of igneous rock called basalt.
Click on image for full size version (92K JPG)
Image from: C. Alexander

Go to a listing of Rocks by mineral group



Last modified November 15, 1997 by the Windows Team

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