Viscosity of Magmas
Viscosity is the resistance to flow (opposite of fluidity). Viscosity depends on primarily on
the composition of the magma, and temperature
. Higher SiO
2
(silica) content magmas have higher viscosity than lower SiO
2
content magmas (viscosity increases with increasing SiO
2
concentration in the magma).
What determines the viscosity of magma quizlet?
The viscosity of magma depends upon
its silica content and temperature
.
Which one of the following is a control on magma viscosity?
A magma’s viscosity is largely controlled by
its temperature, composition, and gas content
(see downloadable programs at the bottom of this page). The effect of temperature on viscosity is intuitive. Like most liquids, the higher the temperature, the more fluid a substance becomes, thus lowering its viscosity.
Which of the following does not control viscosity of a magma?
Temperature Silica Content Amount of gas
None of these affects the viscosity of the magma.
What are the 3 factors affecting the viscosity of magma?
The three factors that influence the viscosity of a lava are
temperature, the dissolved gases it contains, and its chemical composition
.
What are the three major 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.
How does viscosity affects the movement of magma?
High viscosity lavas
flow slowly and typically cover small areas
. … In contrast, low viscosity magmas flow more rapidly and form lava flows that cover thousands of square kilometers.
What are the two main factors that determine the viscosity of magma?
Viscosity of Magmas
Viscosity depends on primarily on
the composition of the magma, and temperature
. Higher SiO
2
(silica) content magmas have higher viscosity than lower SiO
2
content magmas (viscosity increases with increasing SiO
2
concentration in the magma).
What is the relationship between viscosity and temperature quizlet?
An increase in temperature decreases liquid viscosity
because the molecules have more energy to break away from the forces of attraction that hold them together.
What element has the greatest control on magma viscosity?
Of the ten most abundant elements found in magmas (see above), oxygen is the only anion. Silicon, on the other hand, is the most abundant cation. Thus,
the Si-O bond
is the single most important factor in determining the degree of a magma’s viscosity.
What are the 3 processes of magma formation?
There are three principal ways rock behavior crosses to the right of the green solidus line to create molten magma: 1) decompression melting caused by lowering the pressure, 2) flux melting caused by adding volatiles (see more below), and 3) heat-induced melting caused by increasing the temperature.
What are three important factors that affect the explosiveness of a volcanic eruption?
How do each of these factors affect the explosiveness of an eruption? –
Composition, Temperature, Dissolved Gas
. A more viscous (thick) magma will produce a more violent eruption This is controlled in part by the concentration of silica in the magma.
What are the three types of tephra?
- Ash – particles smaller than 2 mm (0.08 inches) in diameter.
- Lapilli or volcanic cinders – between 2 and 64 mm (0.08 and 2.5 inches) in diameter.
- Volcanic bombs or volcanic blocks – larger than 64 mm (2.5 inches) in diameter.
What are the four main factors involved in the formation of magma?
the formation of magma are
temperature, pressure, water content, and mineral content
.
What is viscosity how it varies with temperature?
The
viscosity of liquids decreases rapidly with an increase in temperature
, and the viscosity of gases increases with an increase in temperature. Thus, upon heating, liquids flow more easily, whereas gases flow more sluggishly.
What are the usual components of magma?
Magma is a molten and semi-molten rock mixture found under the surface of the Earth. This mixture is usually made up of four parts:
a hot liquid base, called the melt; minerals crystallized by the melt; solid rocks incorporated into the melt from the surrounding confines; and dissolved gases
.
