Start Radiometric dating isotopes chart

Radiometric dating isotopes chart

Plutonic rocks on the other hand cool very slowly, on the order of a million years or more for some deeply buried and insulated magmas.

The crystals develop an interlocking texture with some of the trace minerals becoming completely surrounded by later forming crystals.

Volcanic rocks, because they are able to cool and crystalize rapidly, have a very fine-grained texture; the individual mineral grains are too small to see easily with the naked eye.

Figure 1 shows a typical discoloration halo around a radioactive mineral inclusion in the mineral pyroxene.

The zone of damage is roughly spherical around a central mineral inclusion or radioactive source.

Granite is a well-known type of plutonic igneous rock, but there are many others as well.

Geologists distinguish these types of rock based on their chemical and mineralogical composition.

True granites are relative latecomers on the geologic scene as they required a number of recycles of crustal material to differentiate and concentrate potassium.