Metamorphic rocks are formed when their respective protoliths are exposed to immense heat and pressure; to an extent that this exposure brings about physical or chemical changes in them and results in formation of new rock.
While sandstone shatters into many grains, quartzite breaks across the grains. It is a non-foliated metamorphic rock formed during the metamorphism of sandstone.
These rocks are most often deduced from single mineral sedimentary rocks.
Because it has been squeezed harder than slate it is often found folded and crumpled. Shale or pelite Shale being the parent rock, is metamorphosed to become a fine grained phyllite, consisting of clay minerals.
Sometimes an invading granite magma permeates the rocks around, filling their joints and planes of bedding, etc.
Today, headstones are made from marble and granite because both of these rocks weather very slowly and carve well with sharp edges. Gneisses also, as a rule, contain more feldspar than schists do, and are tougher and less fissile. However, all minerals are stable only within certain limits, and the presence of some minerals in metamorphic rocks indicates the approximate temperatures and pressures at which they formed.
These huge forces of heat and pressure cause the rocks to be bent, folded, crushed, flattened, and sheared. Formation of Metamorphic Rocks Even though least common of the three types, these rocks are a bit unique as they form from an existing sedimentary rock, igneous rock or an old metamorphic rock.
The huge weight of overlying layers of sediments. Peridotite This rock is primarily composed of talc and contains small amount of chlorite, mica and amphiboles.
Marble has many color variances due to the impurities present at formation.
They are stable at high temperatures and pressures and may remain chemically unchanged during the metamorphic process. It is formed because of comparative low pressures and temperatures, and is referred to as low-grade metamorphism.
The heat and pressure of the Earth's crust bring about profound changes in terms of physical as well as chemical properties, and give new textures to the rock. Metamorphic rocks do not have pores or openings, and may be accompanied with visible layers of crystals.
Non-foliated metamorphic rocks do not have a platy or sheet-like structure. Today it is not very advantageous to use this rock because of its weight and the splitting and cracking over time.
The process requires millions of years in transformation. Many of the original minerals have been altered into flakes. Hornfel is non-foliated and its texture is banded. Shale This metamorphic rock is classified as medium grade, which means it has been formed by more pressure and heat compared to slate.
It appears similar to granite. Basalt The rock consists of amphiboles, is generally dark-colored and heavy, with a weakly foliated structure. Limestone or dolomite Both dolomite and limestone contain calcium carbonate in large concentrations. The best way of learning their various types is by handling and seeing them in reality.
The change in the particle size of the rock during the process of metamorphism is called recrystallization. Marble Marble is among the non-foliated metamorphic rocks produced from the metamorphism of dolostone or limestone. These more intense stages of alteration are not so commonly seen in igneous rocks, because their minerals, being formed at high temperatures, are not so easily transformed or recrystallized.
Some of the different colors of marble are white, red, black, mottled and banded, gray, pink, and green. It is formed when sandstone comes into contact with magma that is deeply buried. The formation of metamorphic rock and the rocks they originated from.
Jan 26, · Metamorphic rock is the result of the transformation of a pre-existing rock type, the protolith, in a process called metamorphism, which means "change in form".
Metamorphic rock is formed underground through a process that changes a rock's molecular structure due to pressure, heat and chemical reactions. A metamorphic rock forms from a parent rock called a protolith.
Depending on conditions, a protolith can transform into any metamorphic rock. Formation of metamorphic rocks. As the Earth's plates move over geologic time, a plate containing igneous or sedimentary rock may become subducted under another plate.
The sheer weight of the material above it can cause the rock to undergo metamorphism. In some cases, heat from the Earth's interior can melt the rock slightly, in a process.
The diagram above shows you where metamorphic rock (YELLOW ZONE) can be produced at a subduction zone. There are 3 factors that cause an increase in pressure which also causes the formation of metamorphic rocks.
The name metamorphic rock defines their formation whereby ‘meta’ means change and ‘morph’ means ‘form.’ Hence, metamorphic rocks are those whose forms have been changed through geological process such as large tectonic movements and magma intrusions.Metamorphic rock formation