How does heat and pressure affect rocks?
Igneous rocks form when rocks are heated to the melting point which forms magma. Metamorphic rocks form from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock.
What are the 7 index minerals?
Common minerals in metamorphic rocks include quartz, feldspar, mica, calcite, and hornblende. Index minerals in metamorphic rocks indicate how much the original rock was metamorphosed, called the grade of metamorphism. Index Minerals minerals include chlorite, epidote, garnet, staurolite, kyanite and sillimanite.
What is Protolith marble?
What is the protolith of marble? Limestone. (A protolith is the parent rock that is metamorphosed into a different rock; metamorphosed limestone is marble.)
What are useful index minerals?
Examples of Index Minerals The most widely used index minerals are, in ascending order of pressure/temperature, are biotite, the zeolites, chlorite, prehnite, biotite, hornblende, garnet, glaucophane, staurolite, sillimanite, and glaucophane.
What are some examples of index minerals?
A mineral that forms only under specific pressure and temperature conditions, and that therefore provides information about the metamorphic history of the rock in which it is found. The minerals kyanite, andalusite, and sillimanite are examples of index minerals.
What controls the formation of index minerals?
Pressure, temperature, and protolith composition are widely recognized as primary controls on index mineral distribution.
What is the index mineral of schist?
As explained above, mica minerals such as chlorite, muscovite, and biotite are the characteristic minerals of schist. These were formed through metamorphism of the clay minerals present in the protolith. Other common minerals in schist include quartz and feldspars that are inherited from the protolith.
What is an index material?
In optics, an index-matching material is a substance, usually a liquid, cement (adhesive), or gel, which has an index of refraction that closely approximates that of another object (such as a lens, material, fiber-optic, etc.).
Is Quartz a good index mineral of metamorphic grade?
Is quartz a good index mineral of metamorphic grade? Why or why not? No because they tend to crystallize in low grade as well as high grade conditions, they are ubiquitous. They do indicate a specific metamorphic condition and are not considered index minerals.
Is feldspar a good index mineral metamorphic grade?
Index Minerals in metamorphic rocks Note Quartz and Feldspar are not index minerals: Why? 2. the reactions of minerals with fluids (for example salty or alkaline water) at high temperatures and pressures.