Different minerals within a rock melt at different temperatures.
The amount of partial melting and the composition of the original rock
determine the composition of the magma. … The higher the amount of silica in the magma, the higher is its viscosity. Viscosity is a liquid’s resistance to flow.
What does magma composition depend on?
The chemical composition of magma can vary depending on
the rock that initially melts (the source rock)
, and process that occur during partial melting and transport. The initial composition of the magma is dictated by the composition of the source rock and the degree of partial melting.
What are the 4 different factors that can control magma compositions?
Magma composition is discussed below, followed by a description of the controlling factors on explosivity
— viscosity, temperature, and the amount of dissolved gases in the magma
.
How does magma change composition over time?
If the magma absorbs part of the rock through which it passes we say that the magma has become contaminated by the crust
. Either of these process would produce a change in the chemical composition of the magma unless the material being added has the same chemical composition as the magma.
What were factors that affect magma composition?
- Temperature plays a role in the formation of the melts in the magma. …
- Pressure can affect the shape and formation of melts.
What are the two composition of magma?
There are three basic types of magma:
basaltic, andesitic, and rhyolitic
, each of which has a different mineral composition. All types of magma have a significant percentage of silicon dioxide. Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium.
What are the three main components of magma?
Magma and lava contain three components:
melt, solids, and volatiles
. The melt is made of ions from minerals that have liquefied. The solids are made of crystallized minerals floating in the liquid melt.
What is the highest amount in the magma?
Explanation:
Oxygen
, the most abundant element in magma, comprises a little less than half the total, followed by silicon at just over one-quarter. The remaining elements make up the other one-quarter. Magmas derived from crustal material are dominated by oxygen, silicon, aluminum, sodium, and potassium.
Where is magma found?
Magma originates
in the lower part of the Earth’s crust and in the upper portion of the mantle
. Most of the mantle and crust are solid, so the presence of magma is crucial to understanding the geology and morphology of the mantle.
What is difference between magma and lava?
Scientists use the term
magma
for molten rock that is underground and lava for molten rock that breaks through the Earth’s surface.
Which magma composition is most violent?
Explosive eruptions are favored by high gas content & high viscosity magmas (
andesitic to rhyolitic magmas
). The explosive bursting of bubbles fragments the magma into clots of liquid that cool as they fall through the air. These solid particles become pyroclasts or volcanic ash.
What is the initial magma composition?
Mafic magmas are low in
silica
and contain more dark, magnesium and iron rich mafic minerals, such as olivine and pyroxene. 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 is its viscosity.
What factors determine whether an eruption will be explosive?
Volcanic eruptions can be explosive, sending ash, gas and lava high up into the atmosphere, or the magma can form lava flows, known as effusive eruptions. Whether an eruption is explosive or effusive largely depends upon
the amount of gas in the magma
.
How deep is magma in the earth?
A layer of molten rock trapped since Earth’s formation may exist where the solid mantle meets the core, a new study says. A layer of searing hot liquid magma trapped since Earth’s formation may lie
1,800 miles (2,900 kilometers) beneath our feet
, new research suggests.
What’s the most active volcano in the world?
Rising gradually to more than 4 km (2.5 mi) above sea level,
Hawaii’s Mauna Loa
is the largest active volcano on our planet.
What is the magma composition of a shield volcano?
Shield volcanoes are composed almost entirely of relatively thin lava flows built up over a central vent. Most shields were formed by
low viscosity basaltic magma
that flows easily down slope away form the summit vent.
