Why Are Lava Flows Typically Finer Grained Than Intrusive Igneous Rocks?

The texture of lava flows is generally finer than that of intrusive igneous rocks. The texture of lava flows reflects the fact that they are composed of two different types of mineral grains. These types of rock contain the lowest silica content. The composition of lava flows is largely related to the types of volcanic activity they underwent.

In intrusive igneous rocks, the crystallization of magma takes a long time to occur. In contrast, lava flows form quickly and cool rapidly, without reaching the earth’s surface. Intrusive rocks consist of a framework of tiny crystals, including some that are so small that it is not possible to see them with the naked eye. Some types of lava flows do not have grains at all, while others form large crystalline structures that can be seen with the naked eye.

Another common confusion about lava and igneous rocks is the texture of lava. While intrusive igneous rocks are typically coarser grained than lava flows, the two are not completely interchangeable. While both types of rocks have similar textures, lava is generally finer grained than intrusive igneous rocks. In this case, the difference can be attributed to the type of volcanic activity and how the material formed.

The color of igneous rocks is determined by their composition. If lava is lighter in color than an intrusive rock, the rock is felsic, while an intermediate rock is called amic. A mixture of these types of rocks has different compositions. In general, felsic rocks have a higher amount of silica than mafic rocks.

In addition to chemical composition, lava flows are usually softer than intrusive igneous rocks. Because the lava cools too fast, it leaves behind a hollow cavity where mineral grains can form. These rocks are called glassy igneous rocks. During the liquid phase of lava, the molten material is filled with gas bubbles.

In addition to being softer, lava flows are usually finer-grained than intrusive igneous rock. This makes them better thermal insulators. If they are softer than intrusive igneous rocks, the lava may have become a liquid. If you see lava flowing in a lake, or a river flowing in the ocean, the lava flow will be much more brittle and fine-grained than its intrusive counterparts.

The difference in texture is important when trying to compare lava flows to other types of igneous rocks. Extrusive rocks are glassy, while intrusive rocks are rougher and have larger crystals. Both types of rocks are formed from the cooling of molten rock at a depth. In other words, lava flows are typically finer grained than intrusive rocks.

Volcanoes produce extrusive igneous rocks when magma escapes from the Earth’s surface. These rocks form at erupting volcanoes and oozing fissures. When exposed to the atmosphere, magma cools rapidly, preventing mineral crystals from growing. Because they are extrusive, lava flows tend to be finer grained than intrusive igneous rocks.

The biggest eruptions that occurred in Iceland were caused by discordant and local inflation of the mantle. These lava flows formed craters and volcano-lakes that filled them with mounds of rhyolitic lava flows. Interestingly, the Columbia Plateau in Washington and Oregon is another example of an extrusive volcanic feature.

Igneous activity occurs in several tectonic settings, including diverging and converging plate boundaries. Other settings include hot spots, rift valleys, and oceanic ridges. The latter involves the eruption of basaltic lava flows and intrusion of dikes, plutons, gabbros, and a variety of other types of igneous rock.