What happens when magma is high in silica?

Lava with high silica content is thick and viscous and does not flow easily. Lava rises to the surface, but is too thick to squeeze through cracks and fissures in the Earth. As the lava continues to rise upward, the pressure continues to build.

Are cone volcanoes high in silica?

Cinder Cone Volcano: A Cinder Cone volcano has low silica levels and high levels of dissolved gas, resulting in liquid lava that erupts explosively due to the enormous pressure built up in the magma chamber. A cone volcano erupts by shooting fountains of burning lava high into the air.

Do cone volcanoes have high or low viscosity?

Unlike the violently explosive eruptions that create large stratovolcanoes, cones form when low-viscosity lava with lots of gas erupts, often as liquid fountains. Lava can be sprayed hundreds of meters through the air.

What is a magma with a high silica content called?

Felsic magmas are higher in silica and contain lighter colored minerals such as quartz and orthoclase feldspar. The higher the amount of silica in the magma, the higher its viscosity.

What kind of magma has a low silica content?

Basaltic Magma: This is a type of magma that is low in silica and forms a rock called basalt when it crystallizes. Bimodal: A bimodal compound is one that is made of two components that differ in their texture and composition. The term is often used to describe volcanic terrain of almost equal parts mafic and felsic rocks.

What kind of magma is associated with volcanoes?

Rhyolite Magma: This type of magma has a high silica content, more than 68% in total. Rift: A rift is formed by an extension of the Earth's crust and is associated with volcanoes. Shield volcano: A very wide volcano with fairly liquid lava and flank slopes of < 5°.

How are the characteristics of a volcanic eruption determined?

Since volcanic eruptions are caused by magma (a mixture of liquid rock, crystals, and dissolved gas) ejected onto the Earth's surface, we must first discuss the characteristics of magma and how magma forms in the Earth. Types of magma are determined by the chemical composition of the magma.

What are the characteristics of a non-explosive magma eruption?

Non-explosive eruptions are favored by low gas content and low viscosity magmas (basaltic to andesitic magmas). If the viscosity is low, non-explosive eruptions usually begin with fire fountains due to the release of dissolved gases.