How is vesicular texture formed?

How is vesicular texture formed?

As magma rises to the surface the pressure on it decreases. When the magma finally reaches the surface as lava and cools, the rock solidifies around the gas bubbles and traps them inside, preserving them as holes filled with gas called vesicles.

How does a rock become vesicular?

Vesicles are the small holes left behind after lava cools and turns into volcanic rock. Vesicles help geologists understand the cooling history of extrusive (volcanic rocks) because lava contains large amounts of dissolved gases that are released as the lava hardens.

Where do vesicular rocks come from?

Vesicles only develop in rocks that cool from a liquid – an igneous rock. Most meteorites come from asteroids, and almost all asteroids are too small to have volcanoes, thus few meteorites are igneous rocks. Most such rocks among the meteorites are basalts.

Which rocks have a vesicular texture?

The vesicles are small cavities formed by the expansion of bubbles of gas or steam during the solidification of the rock. Rock types that display a vesicular texture include pumice and scoria.

Which igneous rock has a vesicular texture and a mafic composition?

Classification of Igneous Rocks

	COMPOSITION
TEXTURE	Felsic	Mafic
Phaneritic	Granite	Gabbro
Aphanitic	Rhyolite	Basalt
Vesicular	Pumice	Scoria

What is a vesicular felsic rock called?

Porphyritic. A vesicular Felix rock is called a: Pumice.

How do pyroclastic rocks form?

Pyroclastic rocks are rocks formed by accumulation of material generated by explosive fragmentation of magma and / or previously solid rock, during the course of a volcanic eruption.

How vesicular and Amygdaloidal structure is formed in basalt?

Basalts are most commonly vesicular. The drop in pressure that a magma experiences as it flows from underground to the Earth’s surface allows water and gases in the lava to form bubbles. Amygdaloids are simply vesicles that have been filled in with a secondary mineral long after the flow cooled.

How are Amygdaloidal textures formed?

If the vesicles in some extrusive rocks are filled by secondary minerals (calcite, silica, etc), the filled vesicles are called Amydules and the texture is termed Amygdaloidal. Pyroclastic Texture = fragmental texture formed by explosive eruptions.

How is glassy texture different from vesicular texture?

Glassy texture refers to a quick/rapid cooling lava that does not have an underlying organized mineral structure visible under a conventional polarized light microscope. Vesicular texture occurs when gases are trapped within a lava flow and minerals crystallize around the gas pocket.

What other ways does sedimentary rocks form?

Sedimentary rock is one of the three main rock groups (along with igneous and metamorphic rocks) and is formed in four main ways: by the deposition of the weathered remains of other rocks (known as ‘clastic’ sedimentary rocks); by the accumulation and the consolidation of sediments; by the deposition of the results of …

What does the coarse and fine grain texture of the rocks indicate about the rocks formed and their respective cooling histories?

Phaneritic texture describes coarse grained rocks. They are characteristic of intrusive (plutonic) rocks, and have crystals that can be seen with the unaided eye. Indicates slow cooling history. These larger crystals are called phenocrysts, while the finer-grained matrix is referred to as the groundmass.

What is vesicular texture in geology?

Scale box in millimeters. Vesicular texture is a volcanic rock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside. This texture is common in aphanitic, or glassy, igneous rocks that have come to the surface of the earth, a process known as extrusion.

What are the different types of vesicular rocks?

Sometimes these can be sources of semi-precious stones such as diamonds. Rock types that display a vesicular texture include pumice and scoria.

What is vesicular olivine basalt?

Vesicular olivine basalt. A volcanic sand grain with many vesicles, viewed with a petrographic microscope. Scale box in millimeters. Vesicular texture is a volcanic rock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside.

What type of rock has a fine-grained texture?

Volcanic rock is formed from quickly cooling lava (also called extrusive igneous rock), and will have a fine-grained texture. Plutonic rock (also called intrusive igneous rock) is formed from slow cooling magma, and will exhibit visible crystals. What can you tell about an igneous rock that has a coarse texture? It is most likely formed underground