Which lava is the most abundant type erupted at oceanic spreading centers?
Basalt is the most common magma erupted along oceanic rift systems.
What is the most abundant lava type?
The most common subaerial lava flows today are pahoehoe, aa, and blocky lavas. Lava surface is cooling very rapidly. The temperature of glowing lava is at least 475 °C.
What types of volcanoes are formed at spreading centers?
Shield volcanoes Shield volcanoes are common at spreading centers or intraplate hot spots. The lava that creates shield volcanoes is fluid and flows easily and creates the shield shape. Shield volcanoes are built by many layers over time and the layers are usually of very similar composition.
What type of lava is erupted at convergent plate boundaries quizlet?
C) Magma at a convergent boundary melts through the continental crust or ocean crust in sediments, all of which are rich in silica. This typically produces rhyolitic or andesitic lavas.
Are usually the most abundant gases emitted during basaltic volcanism?
Water and carbon dioxide are usually the most abundant gases emitted during basaltic volcanism.
Are usually the most abundant gases typically released during volcanism?
By far the most abundant volcanic gas is water vapor, which is harmless. However, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide and hydrogen halides can also be emitted from volcanoes.
What is basaltic lava?
Basaltic lava is another term for mafic lava. Mafic lava is molten rock that is enriched in iron and magnesium and low in silica. When mafic lava cools on the earth's surface, it forms basalt, which is why mafic lava is commonly called 'basaltic lava.
What is andesitic lava?
Andesite is a gray to black volcanic rock with between about 52 and 63 weight percent silica (SiO2). Andesites contain crystals composed primarily of plagioclase feldspar and one or more of the minerals pyroxene (clinopyroxene and orthopyroxene) and lesser amounts of hornblende.
What is spreading center volcano?
Spreading center volcanism occurs at the site of mid-oceanic ridges, where two plates diverge from one another. As the plates are pulled apart, hot asthenosphere rises upward to fill voids of the extended lithosphere.
How is magma formed in the spreading center?
Along mid-ocean ridges (also called spreading centers), tectonic plates are moving apart. Molten rock rises from Earth's mantle into the gap between the separating plates and produces extensive lava flows. Along oceanic trenches, tectonic plates are colliding so that one plate is descending below another plate.
What type of lava erupts from shield volcanoes?
basalt Shield volcanoes are usually basalt but can be constructed of mostly andesitic lava flows. Mauna Loa and Kīlauea erupt almost exclusively basaltic lavas.
What type of lava is produced at divergent plate boundary?
What type of lava most commonly erupts at divergent plate boundaries? Shield volcanoes are produced at divergent plate boundaries and intraplate. Cinder cones are made of small fragments of a variety of compositions usually from a single eruption. They are found with composite and shield volcanoes.
What type of magma is the most abundant type erupted at oceanic and continental subduction zones?
geo quiz 6
| Question | Answer |
|---|---|
| ________ is a major dissolved volatile constituent in both magmas and volcanic gases. | Water |
| Volcanic bombs originate ________. | as erupted magma blobs that partly congeal before falling to the ground |
| ________ magma is the most abundant type erupted at oceanic spreading centers. | Basaltic |
Which of the following gases is the most abundant in a volcanic eruption?
By far the most abundant volcanic gas is water vapor, which is harmless. However, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide and hydrogen halides can also be emitted from volcanoes.
What magma is the most abundant type of magma erupted on Earth?
geo quiz 6
| Question | Answer |
|---|---|
| ________ is a major dissolved volatile constituent in both magmas and volcanic gases. | Water |
| Volcanic bombs originate ________. | as erupted magma blobs that partly congeal before falling to the ground |
| ________ magma is the most abundant type erupted at oceanic spreading centers. | Basaltic |
Is Lahar a lava?
A lahar is a hot or cold mixture of water and rock fragments that flow quickly down the slopes of a volcano. They move up to 40 miles per hour through valleys and stream channels, extending more than 50 miles from the volcano. Lahars can be extremely destructive and are more deadly than lava flows.
Where is andesitic lava found?
Granitic, or rhyolitic, magmas and andesitic magmas are generated at convergent plate boundaries where the oceanic lithosphere (the outer layer of Earth composed of the crust and upper mantle) is subducted so that its edge is positioned below the edge of the continental plate or another oceanic plate.
What is rhyolitic lava?
Rhyolitic lavas are viscous and tend to form thick blocky lava flows or steep-sided piles of lava called lava domes. Rhyolite magmas tend to erupt explosively, commonly also producing abundant ash and pumice.
What occurs at a spreading center?
Spreading centers occur at the boundary between two plates that are moving apart, called divergent plate boundaries. Here the plate motion opens a gap between the plates and magma from the mantle rises up through it.
What is viscous lava?
Lava viscosity determines the kind of volcanic activity that takes place when the lava is erupted. The greater the viscosity, the greater the tendency for eruptions to be explosive rather than effusive. As a result, most lava flows on Earth, Mars, and Venus are composed of basalt lava.
Do shield volcanoes have pahoehoe lava?
The lava flows from shield volcanoes is primarily of two types, pahoehoe — pronounced "pah-hoy-hoy" — and a'a (pronounced "ah-ah," said sharply). Both these types originate from surface eruptions, while a third type, pillow lava, is more likely to form from undersea eruptions.
What type of lava is erupted at convergent plate boundaries?
Composite volcanoes are common along convergent plate boundary. When a tectonic plate subducts, it melts. This creates the thick magma needed for these eruptions.
What is basaltic magma?
Basaltic (or mafic) magma predominates in nonexplosive volcanic eruptions. It is a high-temperature magma (1,200 °C (about 2,200 °F)) characterized by flowing lava, and it is made up of about 45–55 percent silica (SiO2) by weight.
Which of these gases is most abundant in magmas?
The most abundant volatile in magma is water (H2O), followed typically by carbon dioxide (CO2), and then by sulphur dioxide (SO2).
Why is felsic lava more explosive?
Felsic lavas are not as hot, high in silica and volatiles, and have a high viscosity. They are thick and gooey and resist flowing. Their high volatile content makes them potentially highly explosive.
Which type of magma would you expect to produce the most explosive volcanic eruption?
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.
What is volcanic lahar?
Lahar is an Indonesian word describing a mudflow or debris flow that originates on the slopes of a volcano. Small debris flows are common in the Cascades, where they form during periods of heavy rainfall, rapid snow melt, and by shallow landsliding.
Why are lahar and pyroclastic flows?
Pyroclastic flows can generate lahars when extremely hot, flowing rock debris erodes, mixes with, and melts snow and ice as it travel rapidly down steep slopes. Lahars can also be formed when high-volume or long-duration rainfall occurs during or after an eruption.
Where is rhyolitic lava found?
Rhyolite has been found on islands far from land, but such oceanic occurrences are rare. The tholeiitic magmas erupted at volcanic ocean islands, such as Iceland, can sometimes differentiate all the way to rhyolite, and about 8% of the volcanic rock in Iceland is rhyolite.
What is oceanic spreading center?
The oceanic spreading center, also known as the midocean ridge, is an underwater mountainous feature lying between the two lithospheric plates, through which new magma material being continuously spread out and lead to growth of the lithospheric plates.