What is exsolution geology?

exsolution, in mineralogy, process through which an initially homogeneous solid solution separates into at least two different crystalline minerals without the addition or removal of any materials.

What is exsolution texture?

Exsolution texture, a general term for the texture of mineral intergrowth formed by solid exsolution, is a common texture in minerals from both magmatic and metamorphic rocks. Exsolution is a process by which a former fairly homogeneous phase separates into two or more solid solution phases under subsolidus conditions.

What do you mean by lamellae?

: a thin flat scale, membrane, or layer: such as. a : one of the thin plates composing the gills of a bivalve mollusk.

What is the meaning of exsolved?

: to separate or precipitate from a solid crystalline phase : unmix.

Why do we get exsolution texture?

Many igneous pyroxenes show exsolution textures of thin lamellae of one pyroxene in a host of a different composition. These lamellae result from the exsolution of a separate pyroxene phase from a host grain due to subsolidus re-equilibration (that occurs while the mineral is in the solid state) during slow cooling.

What does Perthitic texture mean?

A perthite is an intimate intergrowth of sodic and potassic feldspar resulting from subsolidus exsolution (unmixing of two minerals). Accordingly, plutonic rocks exhibit intra – crystalline textures in alkali feldspar crystals that are not seen in volcanic rocks.

What is a lamellae in anatomy?

In surface anatomy, a lamella is a thin plate-like structure, often one amongst many lamellae very close to one another, with open space between. Aside from respiratory organs, they appear in other biological roles including filter feeding and the traction surfaces of geckos.

What is lamellae in polymer?

Crystallization of polymers is a process associated with partial alignment of their molecular chains. These chains fold together and form ordered regions called lamellae, which compose larger spheroidal structures named spherulites.

What do striations refer?

1a : the fact or state of being striated. b : arrangement of striations or striae. 2 : a minute groove, scratch, or channel especially when one of a parallel series. 3 : any of the alternate dark and light cross bands of a myofibril of striated muscle.

What is gas exsolution?

This causes a reduction in pore pressure that lowers the gas solubility and results in exsolution. The exsolved gas then displaces water from storage, and the specific storage increases because gas compressibility is typically much greater than that of water or aquifer material.

How are graphic texture formed?

Graphic texture is commonly created by exsolution and devitrification and immiscibility processes in igneous rocks. It is called ‘graphic’ because the exsolved or devitrified minerals form lines and shapes which are reminiscent of writing.

What causes Perthitic texture?

A perthite is an intimate intergrowth of sodic and potassic feldspar resulting from subsolidus exsolution (unmixing of two minerals). During the slow cooling experienced by a plutonic rock, alkali feldspar crystals have sufficient time to invert to structures that are stabler at low temperatures.