Metamorphic rocks


It is a set of rocks  that are formed thanks to the pre-existence of others inside the earth, all this through a process called metamorphism. Its transformation arises as a result of a series of mineralogical and structural adjustments , which transform the original rock into a metamorphic rock. Due to their origin, a graduation may exist between igneous and metamorphic rocks, from which they were born. The study of these rocks provides valuable information about all the geological processes that happened on earth and about their possible changes over time.


What are metamorphic rocks?

Through a series of actions such as heat, pressure and chemical fluids, the birth of metamorphic rocks occurs , which as a result of the aforementioned processes, undergo a series of mineralogical and structural adjustments , which give way to their training.

  • features
  • How metamorphic rocks are formed
  • Components (edit)
  • Classification
  • Deposits
  • Structure of metamorphic rocks
  • Textures
  • ID
  • Use
  • Examples of metamorphic rocks


The metamorphic rocks are primarily characterized by the formation of other preexisting rocks. Likewise, these types of rocks are exposed to a constant change of minerals and chemicals which make them unique and unrepeatable.


During the metamorphic processes, we can observe great changes in its density and texture as well as observing a considerable growth of its crystals and re-orientation of the mineral grains within its structure. We can also differentiate by:

  • Foliated texture.
  • Unfoliated texture.

How metamorphic rocks are formed

Through an isochemical process which consists of an invariable chemical process, a reorganization of its compounds takes place , and through high pressures and temperatures, a solid state is entered.

Components (edit)

The components must contain at least 50% terrigens which are called lithoclasts . Its main components are alchemical and orthochemical. Note that one must differentiate between the composition of the igneous rocks , sedimentary limestones and carbonated, which may exhibit similar process and similar components in certain states, but they can not be qualified as metamorphic rocks.


These rocks present an extensive list for their classification , by which it can be distinguished and explained how:

  • Chemical composition .
  • Mineralogical composition
  • Textural characteristics
  • Origin of the original rock.
  • Structural characteristics.


Reservoirs can be affected by metamorphism depending on the production that it generates, which can be exponentially significant for all metamorphism, likewise this deposit is accompanied by a tectonic deformation. This deformation, which is very important for the development of metamorphic rocks, can completely transform the reservoir based on its geometric and petrological arrangement .

Structure of metamorphic rocks

Its structure depends on whether it has or has undergone any type of deformation , in case it has not suffered any deformation or malformation at its base, there is no preferential orientation of the minerals. In case of having suffered some type of deformation, it must present some type of morphological and crystallographic orientation .


Its main textures are:

Granoblastic Texture

They are the crystals which form an equidimensional grain mosaic which has a 120th shape in points where three of them are formed or joined, which are called triple points.

Lepidoblastic texture

They are the tabular minerals which are oriented in parallel according to their planar habits. This texture has an orientation which is found in parallel according to its components since this rock has a planar pattern.

Nematoblastic texture

It is defined by its prismatic or acicular minerals which are oriented parallel to its elongated habit in only one direction.


Its identification is based on the partial or total recrystallization of the crystals of igneous or sedimentary rocks, which due to high temperatures, pressures and constant efforts produce a considerable change. This intensification process is accelerated by the rapid action of magma, as well as the movements of the tectonic plate , which promote the formation of metamorphic rocks.


This type of rock is used to make roof constructions since it has a great waterproofing capacity. Likewise, these types of rocks are frequently used in the carving of sculptures, buildings and / or monuments. The ornamental containers also part of the uses given to the metamorphic rocks.

Examples of metamorphic rocks

  • Basic intrusive rocks
  • Limestone
  • Sandstone
  • Board
  • Sandstone
  • Basalt
  • Gabbro
  • Basalt

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