What type of volcano has basaltic lava flow?

Shield volcanoes Where a volcano produces low viscosity, runny lava, it spreads far from the source and forms a volcano with gentle slopes: a shield volcano. Most shield volcanoes are formed from fluid, basaltic lava flows. Mauna Kea and Mauna Loa are shield volcanoes.

What is a broad volcano made of flat layers of basaltic lava?

As quiet eruptions of basaltic lava spread out in flat layers, they form a broad volcano with gently sloping sides called a shield volcano.

What type of volcano is made up of low viscosity lava and forms a long low profile shape?

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano.

What are basaltic volcanoes?

Basaltic volcanoes are characterized by persistent periods of activity ranging from effusive lava flows to explosive eruptions with variable intensity (i.e., lava fountains to high-intensity, short-lasting paroxysmal events), each posing different types of potential threats to the local population.

Where are basaltic lava flows?

Basaltic lava flows on Earth are erupted on the mid-ocean ridge system, magmatic arcs, ocean islands, and flood basalt terranes in LIPs. The dark lunar mare are plains of basaltic rock formed by impact melting. Lunar lava flow produced by shock melting.

How does a basaltic volcano form?

Basaltic magma is commonly produced by direct melting of the Earth's mantle, the region of the Earth below the outer crust. On continents, the mantle begins at depths of 30 to 50 km. Shield volcanoes, such as those that make up the Islands of Hawai'i, are composed almost entirely of basalt.

What are mafic volcanoes?

Describes magma that contains lower amounts of silica and is generally less viscous and less gas-rich than silicic magma. Tends to erupt effusively, as lava flows.

What type of volcanoes form from wide in layers of lava?

Stratovolcanoes are also called composite volcanoes because they are built of layers of alternating lava flow, ash and blocks of unmelted stone, according to the U.S. Geological Survey.

How do you know if a volcano is felsic or mafic?

So, mafic lavas are hot , low in silica and volatiles, and have relatively low viscosity. They flow easily outward from the vent (where it comes out of the ground), and may travel great distances before completely solidifying. Felsic lavas are not as hot, high in silica and volatiles, and have a high viscosity.

Is basalt igneous sedimentary or metamorphic?

Igneous rock Igneous rock is formed when magma or lava from volcanoes cools. Examples include basalt and granite.

Where is basalt commonly found?

Basalt is the most common composition of lava rocks that cool from magma, liquid rock that rises from the deep Earth at volcanoes. Today basalt is forming at many active rifts, including Iceland, the East African Rift Valley, the Red Sea and the Rio Grande Valley of New Mexico and Colorado.

Are basaltic volcanoes explosive?

Basaltic eruptions are the most common form of volcanism on Earth and planetary bodies. The low viscosity of basaltic magmas inhibits fragmentation, which favours effusive and lava-fountaining activity, yet highly explosive, hazardous basaltic eruptions occur.

Is basaltic magma felsic or mafic?

Summary Table
Magma Type	Solidified Volcanic Rock	Gas Content
Mafic or Basaltic	Basalt	Low
Intermediate or Andesitic	Andesite	Intermediate
Felsic or Rhyolitic	Rhyolite	High

Sep 3, 2015

Is basalt felsic or mafic?

mafic Granite and rhyolite are considered felsic, while basalt and gabbro are mafic (click here for more information on mafic and felsic). Felsic rocks, in general, form the bulk of the continental plates, while mafic basalt forms the seafloor.

Which type of volcanoes have broad bases?

Composite volcanoes have broad bases and steep sides. These volcanoes usually have a large crater at the top. The crater was created during the volcano's last eruption. Composite volcanoes are also called stratovolcanoes.

What is the 3 types of volcanoes?

The Three Classic Types of Volcanoes

Cinder Cone Volcanoes.
Composite Volcanoes (Stratovolcanoes)
Shield Volcanoes.

What volcanoes are felsic?

Fuji in Japan, Mt. Pinatubo in the Philipines, and Mt. Vesuvius in Italy are examples. Relatively cool, viscous felsic (rhyolitic) magma has great difficulty flowing out of a volcano.

What type of igneous rock is basalt?

Basalts are common aphanitic igneous extrusive (volcanic) rocks. Basalts are composed of minute grains of plagioclase feldspar (generally labradorite), pyroxene, olivine, biotite, hornblende and <20% quartz.

Why is basalt The most common volcanic igneous rock?

It has a low silica content which enables this lava to flow quickly and allows volcanic gases to escape without explosive events. It is a fine grained rock and is the most common rock type in the Earth's crust.

Where can you find basaltic magma?

Basaltic magma is formed through dry partial melting of the mantle. The mantle lies just below the crust of the earth. Basalts make up most of the ocean's crust; this is why basaltic magma is typically found in oceanic volcanoes.

What is basalt eruption?

Bibliography. Flood Basalts are high volume eruptions that flood vast areas of the Earth, covering broad regions with flat lying lava surfaces. They are said to be the result of mantle convection through hot spots, which occur sporadically in time and place.

Why is basaltic lava less viscous?

Basalt has a SiO2 content of ≤ 52% and contains relatively more magnesium and iron than more silicic igneous rocks. A basaltic lava flow has a low viscosity due to its low SiO2 content.

Does low viscosity lava have a low silica content?

The cooler the lava, the higher the viscosity (the thicker it is). Composition: he more felsic the lava (the more silica in the lava), the higher the viscosity because silica forms chains in the cooling lava even before it crystallizes. The more mafic the lava (the less silica in it), the lower the viscosity.

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.

Why is basalt mafic?

Chemically, mafic rocks are sometimes defined as rocks with a silica content between 45 and 55 wt%, corresponding to the silica content of basalt in the TAS classification. Such rocks are enriched in iron, magnesium and calcium and typically dark in color.

Which type of volcanoes have broad bases and steep slopes and are formed by alternating layers of lava?

Some of the Earth's grandest mountains are composite volcanoes–sometimes called stratovolcanoes. They are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs and may rise as much as 8,000 feet above their bases.

What are the types of volcanoes describe each?

These terms generally describe the volcanic landform types. Constructional volcanoes are topographic highs and are built by eruptions that build volcanic edifices. Cinder cones, composite volcanoes, and shield volcanoes are constructional. Excavational volcanoes have negative relief (below the general land surface).

Why do shield volcanoes have basaltic lava?

Shield volcanoes are usually constructed almost entirely of basaltic and/or andesitic lava flows which were very fluid when erupted. They are built by repeated eruptions that occurred intermittently over vast periods of time (up to a million years or longer).

Is basalt mafic or felsic?

Is basalt an igneous?

Basalts are common aphanitic igneous extrusive rocks composed of minute grains of Plagioclase feldspar (Labradorite), Pyroxene, Olivine, Biotite, Hornblende, and less than 20% Quartz.