Magmatism(incom) Flashcards
defined as molten
rock material produced by
partial melting of the mantle and
crust. It contains liquids, gases,
crystals and rock fragments.
Magma
Temperature increases
with depth, which is called
_. This
increase will obviously
induce melting.
geothermal gradient
Decrease in pressure causes
adiabatic decompression. As
pressure is decreased, melting
temperatures of materials
decrease.
are substances that evaporate easily and can exist in gaseous form in the surface of Earth
Volatiles
Example of volatiles
water and carbon dioxide
is the process of reducing a substance’s melting point by introducing impurities. When volatiles are added to rocks, their melting point decreases.
Flux melting
When water or carbon dioxide are introduced to rock, flux melting occurs which cause the rock to melt.
occurs along plate boundaries or margins and sometimes within the plate.
Magmatism
In effect, hot mantle rock penetrates the crust and becomes magma.
Plate boundaries can be classified as convergent, divergent, and transform.
temperature, pressure, volatiles
Classification of Magma
Tholeiitic magmas or tholeiites
Calc-alkaline basalts
Alkaline basalts
Carbonatites
are produced by large degree of melting
Tholeiitic magmas or tholeiites
form along convergent plate boundaries above subduction zones
Calc-alkaline basalts
form from smaller degree of partial melting, which results in alkali-rich and silica depleted magma of diverse compositions
Alkaline basalts
are the only magmas that are not produced by silicate source rock
Carbonatites
As pressure is decreased, melting temperatures of materials decrease.
Magmas are classified according to the ratio between the alkalis and silica content.
is the process where magma rises to the surface of the Earth as lava.
It can be viewed as a destructive event as it could damage infrastructures and causes injuries and short-term climate change. It is also a constructive process as seen in the Earth’s early history.
Volcanism
is the process where magma rises to the surface of the Earth as lava.
It can be viewed as a destructive event as it could damage infrastructures and causes injuries and short-term climate change. It is also a constructive process as seen in the Earth’s early history.
Volcanism
The atmosphere was formed through the release of volcanic gases, and new oceanic crust is continuously produced along mid-oceanic ridges.
Many islands are also formed through volcanic processes
a hill or mountain where lava, pyroclastic materials, and gases erupt. It can form along plate boundaries or within the plate.
volcano
In divergent plate boundaries, volcanism manifests as ridges or fissures where products of decompression melting erupt.
divergent
Convergent plate boundaries host a large number of volcanoes. Lava flows and pyroclastic materials make up these volcanoes.
Convergent
may be classified as pahoehoe (pronounced as pah-hoy-hoy) and aa (pronounced as ah-ah)
Types of Lava Flows
Pahoehoe
Aa
has a smooth and ropy surface.
Pahoehoe
has a smooth and ropy surface.
Pahoehoe
jagged and angular corners.
Aa
Lava that solidifies forms
volcanic rocks.
Minerals comprising these
rocks are fine-grained
compared with plutonic rocks
that are coarser.
Example of volcanic rocks
basalt, andesite, and rhyolite.
