What is the most abundant type of magma?
Basalt is the most common magma erupted along oceanic rift systems.
Which statement about the May 1980 eruption of Mount Saint Helen is false?
geo quiz 6
| Question | Answer |
|---|---|
| The big volcanoes of Hawaii | shield volcanoes |
| Which statement about the May, 1980, eruption of Mount St. Helens is FALSE? | During the eruptive period, the mountain peak was substantially built up by new lava flows and pyroclastic debris. |
Which of the following magma types has the highest gas content?
The amount of gas in a magma is also related to the chemical composition of the magma. Rhyolitic magmas usually have higher gas contents than basaltic magmas.
What best describes the source of water in gas rich magmas?
What best describes the source of water in gas-rich magmas? Water-rich sediment in subduction zones.
Which is the most abundant element composition in magma?
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.
What are the components of magma?
Magma compositions vary, but will have eight main elements in different proportions. The most abundant elements are oxygen and silicon, followed by aluminum, iron, calcium, sodium, magnesium, and potassium. These eight elements are also the most abundant in Earth's crust (Figure 7.2).
How does an eruption of Mount Saint Helens differ from an eruption of Kilauea?
The eruption of Mount St. Helens (5/18/1980) was a violent explosive event where the volcano blew out the north flank spreading ash and rock debris up to 18 km around. … The typical eruption of Kilauea by contrast is gradual with lava slowing pouring out from its vents and has been active since 1983.
When Mount St. Helens erupted What happened right after the snow on the volcano melted?
The heat of the initial eruption melted and eroded the glacial ice and snow around the remaining part of the volcano. The water mixed with dirt and debris to create lahars, or volcanic mudflows. According to USGS, the lahars reached speeds of 90 mph (145 km/h), and demolished everything in their path.
Which gases are found in magma?
The main gases dissolved in magma are water vapor, carbon dioxide, and sulfur gases, with lesser amounts of hydrogen, hydrochloric acid, and hydrofluoric acid.
What is the major 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 three components make up most magmas?
Magma and lava contain three components: melt, solids, and volatiles. The melt is made of ions from minerals that have liquefied.
What is magma composition?
Magmas can vary widely in composition, but in general they are made up of only eight elements; in order of importance: oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, and potassium (Figure 3.2. 1).
Which is the most abundant element?
Hydrogen Hydrogen is the most abundant element in the Universe; helium is second.
How do cinder cones compare in size and steepness of their flanks with shield volcanoes?
Cinder cones are much smaller and steeper than shield volcanoes.
How does the eruption of Mount St Helens on May 18 1980 compare to a typical eruption of Hawaiis Kilauea Volcano?
Helens eruption was more explosive than a typical eruption of the Kilauea volcano. The Mount St. Helens eruption destroyed a significant portion of the top of the volcano, whereas a typical eruption from the Kilauea volcano does not destroy the top of the volcano.
What caused Mt St Helens eruption?
On the morning of May 18, 1980, after weeks of small tremors, a magnitude 5.1 earthquake shook beneath Mount St. Helens and triggered an enormous eruption.
Did the magma that produced the May 18 1980 eruption of Mount St. Helens have a relatively low or high silica content explain?
The answer lies in the chemical compositions of the magmas produced by the two volcanoes. The basalt magma erupted by Kīlauea contains about 52% silica and about 0.5 % water while the dacite lava erupted by Mount St. Helens in 1980 contained more of both: about 64% silica and about 4% water.
Why are dissolved gases dissolved in magma?
Magma contains dissolved gases, which provide the driving force that causes most volcanic eruptions. As magma rises towards the surface and pressure decreases, gases are released from the liquid portion of the magma (melt) and continue to travel upward and are eventually released into the atmosphere.
What is the composition of magma and how is it formed?
The composition of magma depends on the rock it was formed from (by melting), and the conditions of that melting. Magmas derived from the mantle have higher levels of iron, magnesium, and calcium, but they are still likely to be dominated by oxygen and silicon.
How magmas are formed?
Magma forms from partial melting of mantle rocks. As the rocks move upward (or have water added to them), they start to melt a little bit. These little blebs of melt migrate upward and coalesce into larger volumes that continue to move upward. They may collect in a magma chamber or they may just come straight up.
What components make up most magmas?
Most magmas consist of three materials: a liquid component a solid component and a gaseous component.
How magma water is formed?
Magmatic water, also known as juvenile water, is an aqueous phase in equilibrium with minerals that have been dissolved by magma deep within the Earth's crust, and is released to the atmosphere during a volcanic eruption.
Which is the most abundant gas?
nitrogen Gases. The most abundant naturally occurring gas is nitrogen (N2), which makes up about 78% of air. Oxygen (O2) is the second most abundant gas at about 21%. The inert gas argon (Ar) is the third most abundant gas at 0.93%.
What are the two most abundant?
The Most Abundant Element in the Universe, the Earth, and the Human Body. Hydrogen and Oxygen are two of the most abundant elements. Anne Marie Helmenstine, Ph.
How does shield volcanoes cinder cones and composite cones differ from one another?
Composite cones are tall, cone shaped volcanoes that produce explosive eruptions. Shield volcanoes form very large, gently sloped volcanoes with a wide base. Cinder cones are the smallest volcanic landform. They are formed from accumulation of many small fragments of ejected material.
How would you tell a shield volcano cinder cone and stratovolcano apart if you were in the field?
Size Differences. Cinder cone volcanoes are relatively small, rarely exceeding 1,000 feet tall. Composite volcanoes, also known as stratovolcanoes, are towering structures, often rising more than 10,000 feet. Shield volcanoes are broad, typically 20 times wider than they are high.
Why are some volcanic eruptions like Mt St Helens more explosive than others like Hawaiian volcanoes?
Mount St. Helens' magma is inherently more explosive than the Kīlauea magma: it has more water in it than Kīlauea magma, and is delivered to the surface at a higher pressure because of higher magma viscosity. So Mount St. Helens tends to have explosive eruptions and Kīlaueaa eruptions are generally non-explosive.
What happened in the Cascade Range of southwestern Washington on May 18 1980?
The cataclysmic eruption of Mount St. Helens, Washington, on May 18, 1980, formed a deep north-facing horseshoe-shaped crater. Small eruptions from 1980 to 1986 built a lava dome. The lava dome can be seen here steaming within the crater.
How does a hot spot supervolcano such as Yellowstone form?
ANSWER: Because the lithosphere ocean plate move with plate tectonics over the stationary mantle based hot-spot, forming a series of volcanoes.
What composition magma is beneath the Mt St Helens volcano and why?
Mt. St. Helens was explosive because the magma was more viscous (more "sticky") and felsic. Hawaiian volcanoes are the result of subduction.