Are Hawaii’s volcanoes mafic or felsic?
Because the viscosity is low, mafic magma tends to produce gently sloping volcanic cones, called shield volcanoes….
|Property||mafic magma||Felsic magma|
|Example of rock||basalt||andesite|
|Type of rash||expansive||explosive|
|Location||hotspots, mid-ocean ridges||subduction zones|
Is Mt St Helens Felsic or Mafic?
Systematic variations in the composition of volcanism over the past few thousand years at Mount St. Helens imply that the magma chamber is zoned, from more felsic at the top to more mafic at the bottom.
Which volcanoes have viscous lava?
Stratovolcano. Stratovolcanoes have relatively steep sides and are more cone-shaped than shield volcanoes. They are formed of viscous, sticky lava that does not flow easily. Lava therefore accumulates around the vent forming a steep-sided volcano.
What type of volcano would be typical of felsic lavas?
Composite volcanoes They tend to be made up of felsic to intermediate rocks and the viscosity of the lava means that eruptions tend to be explosive. Viscous lava cannot travel far up the volcano’s flanks before it solidifies, creating the steep slopes of a composite volcano.
Does mafic lava flow slowly?
In general, the more felsic the magma, the higher its volatile content. Their high volatile matter content makes them potentially highly explosive. Shield volcanoes. Because mafic lava is low viscosity, when it erupts from a volcano, it flows downriver from the vent, gradually cooling and crystallizing.
What is the most explosive type of volcano?
Because they form in a system of underground conduits, stratovolcanoes can blow up the sides of the cone as well as the summit crater. Stratovolcanoes are considered the most violent.
How are mafic volcanoes different from felsic volcanoes?
Mafic volcanoes: Volcanoes that produce mafic lava have very low explosiveness due to the ease with which the lava flows and the few volatiles (such as oxygen and silicon) present in the lava. This forms shield volcanoes, which are large, gently sloping volcanoes like those in Hawaii.
What type of volcano has thick, viscous lava?
Composite volcanoes, sometimes known as stratovolcanoes, are steep-sided cones formed from layers of ash and [lava] flows. Eruptions are explosive due to the thick, highly viscous lava produced by composite cone volcanoes.
Where does the name mafic lava come from?
The name is derived from the Andes Mountains, as it is a rock commonly found among stratovolcanoes in the mountain range. “Mafic” is a term used to describe the densest lava flows. The word derives from a compound of the chemical symbols magnesium (Ma) and iron (Fe).
What type of lava does a shield volcano produce?
Mafic lava forms basalt and is associated with lava flows seen on the Hawaiian Islands and similar shield volcanoes. The type of lava emitted during an eruption can reveal intimate details of not only the volcano’s inner workings, but also the underlying geological processes that govern the Earth’s surface.