What is the texture for an extrusive igneous rock that cools the rapidly with no holes?

What is the texture for an extrusive igneous rock that cools the rapidly with no holes?

aphanitic texture
Extrusive igneous rocks have a fine-grained or aphanitic texture, in which the grains are too small to see with the unaided eye. The fine-grained texture indicates the quickly cooling lava did not have time to grow large crystals. These tiny crystals can be viewed under a petrographic microscope [1].

What is the texture of extrusive igneous rocks?

The texture of extrusive rocks is characterized by fine-grained crystals indistinguishable to the human eye, described as aphantic. Crystals in aphantic rocks are small in size due to their rapid formation during eruption.

What is the texture of an igneous rock that cools quickly?

glassy texture
Very quickly cooled lavas, typically those quenched in water, will have a glassy texture. They cool too quickly to form crystals. Glasses do not have an orderly arrangement of atoms and there are therefore no minerals, in the strict sense, in them. Volcanic glass is called obsidian.

Which texture is most common in extrusive igneous rocks?

They are characterized by fine-grained textures because their rapid cooling at or near the surface did not provide enough time for large crystals to grow. Rocks with this fine-grained texture are called aphanitic rocks. The most common extrusive rock is basalt.

What is the example of extrusive igneous rock?

Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals. Some cool so quickly that they form an amorphous glass. These rocks include: andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff.

What are the 5 textures of igneous rocks?

Igneous textures are used by geologists in determining the mode of origin of igneous rocks and are used in rock classification. There are six main types of textures; phaneritic, aphanitic, porphyritic, glassy, pyroclastic and pegmatitic.

What is the rarest igneous rock?

Komatiite is a very rare extrusive igneous rock only formed from incredibly hot magnesium-rich magma. The lava is so hot that it flows like water.

What are the three methods of intrusive?

Igneous intrusions form when magma cools and solidifies before it reaches the surface. Three common types of intrusion are sills, dykes, and batholiths (see image below).

Which type of igneous intrusion is the largest?

Lopoliths. Lopoliths are the largest known intrusions of dense magma and form a thick saucer shape within the surrounding country rocks.

What are the characteristics of an extrusive igneous rock?

Faster cooling rates produce smaller individual crystals in the rock Extrusive igneous rocks tend to cool quickly and are characterized by smaller grains that produce a fine-grained rock. Aphanitic is the term used to describe very fine grained rocks.

What makes a rock have a glassy texture?

At high degrees of undercooling, both the growth rate and nucleation rate will be low. Thus few crystals will form and they will not grow to any large size. The resulting texture will be glassy, with a few tiny crystals called microlites. A completely glassy texture is called holohyaline texture.

Where does magma cool to form an igneous rock?

Magma can cool to form an igneous rock either on the surface of the Earth – in which case it produces a volcanicor extrusive igneous rock, or beneath the surface of the Earth, – in which case it produces a plutonicor intrusive igneous rock. Characteristics of Magma Types of Magma

What are the factors that affect the texture of a rock?

Other factors involved are: The diffusion rate – the rate at which atoms or molecules can move (diffuse) through the liquid. The rate of nucleation of new crystals – the rate at which enough of the chemical constituents of a crystal can come together in one place without dissolving.