Viscosity of Magmas
Mafic magma is made of denser elements, so it is more dense. Felsic magma has more silica tetrahedrons, which means felsic magmas have more oxygen. The bonds of oxygen are really what determines the viscosity of magma, because they tend to 1.
Also, what determines the viscosity of lava? Viscosity is a fluid’s resistance to flow. Temperature, composition, and volatile (gas) content largely determine the viscosity of lava. Temperature: The hotter the lava, the lower the viscosity (the thinner it is). The cooler the lava, the higher the viscosity (the thicker it is).
Furthermore, what are the 3 types of magma?
The high temperatures and pressure under Earth’s crust keep magma in its fluid state. There are three basic types of magma: basaltic, andesitic, and rhyolitic, each of which has a different mineral composition.
What is the difference between high and low viscosity magma?
High viscosity magma is very thick and pasty. Low Viscosity magma is thin and runny with little dissolved gas. It usually erupts with thin flows of lava very quietly.
What affects magma viscosity?
Magmas that have a high silica content will therefore exhibit greater degrees of polymerization, and have higher viscosities, than those with low-silica contents. The amount of dissolved gases in the magma can also affect it’s viscosity, but in a more ambiguous way than temperature and silica content.
Is magma hot or cold?
Its temperature is usually 1,380 degrees Fahrenheit (750 degrees Celsius), according to an analysis of the crystals. Cooper and Kent think the magma stored under Mount Hood quickly shifts from cold to hot once newer, warmer molten rock arrives from lower levels, deeper in Earth’s crust or mantle.
What do you mean by viscosity?
If I fill the same cup with water, for example, the cup will drain much more quickly. Viscosity is a measure of a fluid’s resistance to flow. It describes the internal friction of a moving fluid. A fluidwith large viscosity resists motion because its molecular makeup gives it a lot of internal friction.
Is mafic magma viscous?
Mafic magmas are low in silica and contain more dark, magnesium and iron rich mafic minerals, such as olivine and pyroxene. Viscosity determines what the magma will do. Mafic magma is not viscous and will flow easily to the surface. Felsic magma is viscous and does not flow easily.
Is felsic magma explosive?
Explosive Eruptions Felsic magmas erupt explosively because of hot, gas-rich magma churning within its chamber. That is why it is so dangerous to inhale the air following an eruption. Scorching hot tephra, ash, and gas may speed down the volcano’s slopes at 700 km/h (450 mph) as a pyroclastic flow.
What is felsic lava?
In geology, felsic is an adjective describing igneous rocks that are relatively rich in elements that form feldspar and quartz. Felsic magma or lava is higher in viscosity than mafic magma/lava. Felsic rocks are usually light in color and have specific gravities less than 3.
What is basaltic magma?
Basaltic lava, or mafic lava, is molten rock enriched in iron and magnesium and depleted in silica. Basaltic magmas are formed by exceeding the melting point of the mantle either by adding heat, changing its composition, or decreasing its pressure. Underwater, basaltic lavas are erupted as pillow basalts.
What is granitic magma?
Granitic, or rhyolitic, magmas and andesitic magmas are generated at convergent plate boundaries where the oceanic lithosphere (the outer layer of Earth composed of the crust and upper mantle) is subducted so that its edge is positioned below the edge of the continental plate or…
What is the importance of magma?
Most of the mantle and crust are solid, so the presence of magma is crucial to understanding the geology and morphology of the mantle. Differences in temperature, pressure, and structural formations in the mantle and crust cause magma to form in different ways.
What is the characteristics of magma?
Magma (Characteristics, Types, Sources, and Evolution) A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase.
What are the properties of magma?
Several interrelated physical properties determine the characteristics of magma, including chemical composition, viscosity, dissolved gases, and temperature.
What does basaltic mean?
[ b?-sôlt′, bā′sôlt′ ] A dark, fine-grained, igneous rock consisting mostly of plagioclase feldspar and pyroxene, and sometimes olivine. Basalt makes up most of the ocean floor and is the most common type of lava.
How is magma formed?
Magma Composition Magma is primarily a very hot liquid, which is called a ‘melt. ‘ It is formed from the melting of rocks in the earth’s lithosphere, which is the outermost shell of the earth made of the earth’s crust and upper part of the mantle, and the asthenosphere, which is the layer below the lithosphere.
What is the origin of magma?
The Origin of Magmas. Magma forms by partial melting of upper mantle and crust. Partial melt means that only a fraction of the available material forms a melt, and that the remainder stays solid. The partial melt rises because of its lower density and ascends through he crust.