What is the protolith of the metamorphic rock?
What is the protolith of the metamorphic rock?
A protolith (from Ancient Greek πρωτο (prōto) ‘first’, and λίθος (líthos) ‘stone’) is the original, unmetamorphosed rock from which a given metamorphic rock is formed. For example, the protolith of a slate is a shale or mudstone. Protoliths are non-metamorphic rocks and have no protoliths themselves.
What are the source rocks protoliths for metamorphic rocks?
Metamorphic grade is the degree to which pressure and temperature have altered parent rock. Rocks start as a protolith and progress up from low grade to high grade. Foliated metamorphic rocks increase metamorphic grade from slate→phyllite→schist→gneiss. 2.
How are metamorphic rocks Fromed?
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.
What are our Protoliths?
A protolith is the original, unmetamorphosed rock from which a given metamorphic rock is formed, e.g. the protolith of a slate is a shale or mudstone.
Is Basalt a protolith?
Basalt is the most common mafic protolith. It can turn into mafic metamorphic rocks such as greenschist and amphibolites with chlorite, actinolite, biotite, hornblende, or plagioclase in them, depending on metamorphic grade.
In what two ways can the parent rock affect the metamorphic process?
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 (direction) of pressure during metamorphism. The amount and type of fluid (mostly water) that is present during metamorphism.
Is marble metamorphic rock?
The main difference between limestone and marble is that limestone is a sedimentary rock, typically composed of calcium carbonate fossils, and marble is a metamorphic rock.
Which of these is an example of a metamorphic rock?
Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite. Slate and quartzite tiles are used in building construction. Marble is also prized for building construction and as a medium for sculpture.
What happens to protoliths in metamorphic rocks after metamorphism?
A fluid phase may introduce or remove chemical substances into or out of the rock during metamorphism, but in most metamorphic rock, most of the atoms in the protolith are be present in the metamorphic rock after metamorphism; the atoms will likely be rearranged into new mineral forms within the rock.
What types of sedimentary rocks are protoliths?
The most important sedimentary protoliths are pelitic (clay-stones), quartzo-feldspathic, carbonate rocks and mixtures of the three groups, such as marls (carbonate-rich pelitic sediments to clay-rich carbonates). Figure 6 shows metamorphic rock names in relation to protolith and grade of metamorphism. Figure 6.
What are some examples of regional metamorphism?
The deeper the rocks, the greater the metamorphism. The photos in Figures 8.4 and 8.5 below show two outcrops of regional metamorphic rocks. Mountain building brings rocks from deep in Earth to the surface. So, many examples of regional metamorphism are found in mountain belts, for example the outcrop in Green Mountains in Figure 8.4, above.
What is the chemical composition of a protolith?
Chemical composition of the protolith. If the protolith is an arenite, made mostly of the mineral quartz (SiO 2 ), metamorphism cannot turn the rock into a marble, which is made of the mineral calcite (CaCO 3 ). In fact, as a result of metamorphism, a pure quartz arenite will become quartzite.
