What is the texture and composition of metamorphic rocks?
TEXTURES Textures of metamorphic rocks fall into two broad groups, FOLIATED and NON-FOLIATED. Foliation is produced in a rock by the parallel alignment of platy minerals (e.g., muscovite, biotite, chlorite), needle-like minerals (e.g., hornblende), or tabular minerals (e.g., feldspars).
What is metamorphic rock composed of?
Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors. Conditions like these are found deep within the Earth or where tectonic plates meet.
How is the composition of metamorphic rocks changed?
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. Ions may move between minerals to create minerals of different chemical composition.
What are the unique characteristics of metamorphic rocks?
Metamorphic rocks were once igneous or sedimentary rocks, but have been changed (metamorphosed) as a result of intense heat and/or pressure within the Earth’s crust. They are crystalline and often have a “squashed” (foliated or banded) texture.
What type of rock can form a metamorphic rock?
Igneous – they form from the cooling of magma deep inside the earth. They often have large crystals (you can see them with the naked eye).
What is a common structure of metamorphic rock?
Metamorphic rocks are formed from preexisting solid rock by mineralogical, structural, and chemical changes in response to extreme changes in temperature, pressure, and/or shearing stress. Common metamorphic rocks include marble, gneiss, quartzite, Gneiss with blue quartz lenses. mylonite, slate, hornfels.
What produces metamorphic rock?
Metamorphic rock is produced from either igneous rock (rock formed from the cooling and hardening of magma) or sedimentary rock (rock formed from compressed and solidified layers of organic or inorganic matter). Most of Earth’s crust is made up of metamorphic rock.
What is a good example of a metamorphic rock?
The study of metamorphic rocks (now exposed at the Earth’s surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth’s crust. Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.