What does a porphyritic texture indicate about a rock?

What does a porphyritic texture indicate about a rock?

What does a porphyritic texture indicate about the cooling history of an igneous rock? It indicates that crystals were formed at depth (slow cooling) and then the magma moved to a shallow depth or erupted (fast cooling).

What does a porphyritic texture indicate?

The large crystals are called phenocrysts and the fine-grained matrix is called the groundmass or matrix. Porphyritic texture indicates the magma body underwent a multi-stage cooling history, cooling slowly while deep under the surface and later rising to a shallower depth or the surface where it cooled more quickly.

Which of the following words could be used to describe portions of a rock with porphyritic texture?

were the first rocks to exist on the Earth. crystallized at depth from intermediate-composition magma, then rose to the surface and became a lava flow. Which of the following words could be used to describe portions of a rock with a porphyritic texture? is felsic in composition.

What does a porphyritic igneous texture indicate about the environment in which it cooled?

What does a porphyritic texture indicate about the history of an igneous rock? The rock experienced a two-stage cooling history: cooling at depth forming larger crystals, being brought to the surface by magma, the remaining liquid cools more quickly forming smaller crystals.

What are porphyritic rocks used for?

Thus, “imperial”-grade porphyry was prized for monuments and building projects in Imperial Rome and thereafter. Subsequently, the name was given to any igneous rocks with large crystals. The adjective porphyritic now refers to a certain texture of igneous rock regardless of its chemical and mineralogical composition.

Why igneous rocks are strong because of their?

The key concept about all igneous rocks is that they were once hot enough to melt. Because their mineral grains grew together tightly as the melt cooled, they are relatively strong rocks. They’re made of primary minerals that are mostly black, white, or gray.

What is the cooling history of an igneous rock with a porphyritic texture?

Porphyritic:a mixture of large and small crystals – perhaps a two-stage cooling history with the large crystals (the phenocrysts) cooling slowly and the small crystals (the groundmass) cooling more quickly. The rock to the right has a phaneritic texture; individual grains can be seen.

What does a mixture of grain sizes in a porphyritic igneous rock tell us about its cooling history?

What does the mixture of grain size in a porphyritic igneous rock indicate about its cooling history? This indicates that some cooled slowly at depth, so that large phenocrysts form, then the melt erupted and the remainder cools quickly.

What kind of rock has a porphyritic texture?

Porphyry is an igneous rock characterized by porphyritic texture. Porphyritic texture is a very common texture in igneous rocks in which larger crystals (phenocrysts) are embedded in a fine-grained groundmass. Porphyry is an igneous rock that contains larger crystals (phenocrysts) in a fine-grained groundmass.

How are phenocrysts embedded in porphyry igneous rocks?

Porphyritic texture is a very common texture in igneous rocks in which larger crystals (phenocrysts) are embedded in a fine-grained groundmass. Porphyry is an igneous rock that contains larger crystals (phenocrysts) in a fine-grained groundmass. K-feldspar phenocrysts in this sample. Width of view 7 cm.

What kind of texture do andesite rocks have?

Porphyritic Texture. Rocks with porphyritic (“POR-fi-RIT-ic”) texture like this andesite have larger mineral grains, or phenocrysts (“FEEN-o-crists”), in a matrix of smaller grains. In other words, they display two distinctive sizes of grains that are visible to the naked eye.

What are the different types of rock textures?

Aphanitic Texture. This includes the size and quality and interrelations of its grains and the fabric they form. Larger scale features, such as fractures and layering, are considered rock structures in comparison. There are nine main types of igneous rock textures: Phaneritic, vesicular, aphanitic, porphyritic, poikilitic, glassy, pyroclastic,…