Table of Contents
How does mineral composition change during metamorphism?
Metamorphism occurs because some minerals are stable only under certain conditions of pressure and temperature. When pressure and temperature change, chemical reactions occur to cause the minerals in the rock to change to an assemblage that is stable at the new pressure and temperature conditions.
Does mineral composition affect metamorphism?
The main factors that control metamorphic processes are: The mineral composition of the parent rock. The temperature at which metamorphism takes place. The amount and type of pressure during metamorphism.
What changes in texture and composition occur during metamorphism?
Metamorphism is the alteration of a preexisting rock (the parent rock) due to heat and pressure caused by burial in the earth. The parent rock must adapt to the new conditions and it does so by changing mineral composition and texture. These rocks with new texture and composition are metamorphic rocks.
Why do minerals rearrange metamorphic rocks?
Rocks change during metamorphism because the minerals need to be stable under the new temperature and pressure conditions. The need for stability may cause the structure of minerals to rearrange and form new minerals. Foliation normally forms when pressure is exerted in only one direction.
What influences the mineral composition of the resulting metamorphic rock?
Temperature and pressure are important factors in determining the new minerals that form in a metamorphic rock. Different minerals form under different pressure and temperature conditions. The higher temperatures also speed up the chemical reactions that take place during metamorphism.
What does mineral composition mean?
The composition of a mineral can be expressed as a CHEMICAL FORMULA, which simply gives the proportions of the different elements and groups of elements in the mineral. The latter notion (groups of elements) comes into play for those minerals which have a restricted range of composition.
How do mineral composition of rocks change as the rocks undergo metamorphism?
During metamorphism the mineral content and texture of the protolith are changed due to changes in the physical and chemical environment of the rock. Metamorphism can be caused by burial, tectonic stress, heating by magma, or alteration by fluids. A rock undergoing metamorphism remains a solid rock during the process.
How does metamorphism change the shape of a rock?
Metamorphic rock forms from a pre-existing rock or protolith. During metamorphism, new minerals grow at the expense of old minerals, and/or the shape, size, and arrangement of grains in the rock may change. Changes occur in the solid state because melting doesn occur.
What causes changes in the protolith during metamorphism?
During metamorphism the protolith undergoes changes in texture of the rock and the mineral make up of the rock. mostly in the solid state and are caused by changes in physical or chemical conditions, which in turn can be caused by such things as burial, tectonic stress, heating by magma or interactions with fluids.
What kind of minerals are produced in metamorphic rocks?
New minerals grow, but the rock does not appear to be metamorphosed. The main minerals produced are often the Zeolites. Burial metamorphism overlaps, to some extent, with diagenesis, and grades into regional metamorphism as temperature and pressure increase.
Why are metamorphic rocks stable under pressure and temperature?
Metamorphism occurs because rocks undergo changes in temperature and pressure and may be subjected to differential stress and hydrothermal fluids. Metamorphism occurs because some minerals are stable only under certain conditions of pressure and temperature. When pressure and temperature change, chemical reactions