What is the viscosity of andesitic lava?

102 to 107 Pa s102 to 107 Pa s, which is due to a wide range in phenocryst contents from 0 (phenocryst‐free andesitic melt) to ∼50 vol % (50 vol % rhyolitic melt + 50 vol % phenocrysts).

Does andesitic lava have low viscosity?

Siliceous Lava Flows – High viscosity andesitic and rhyolitic lava flows, because they can’t flow very easily, form thick stubby flows that don’t move far from the vent.

What is the viscosity of lava?

Viscosity of Magmas

Thus, basaltic magmas tend to be fairly fluid (low viscosity), but their viscosity is still 10,000 to 100,0000 times more viscous than water.

What type of lava is most viscous?

The most viscous lava is cool, high-silica lava called rhyolitic lava. This lava contains about 65-75% silicate and erupts at a temperature of about 650-800 degrees Celsius. Flows of this type of lava don’t move far from the vent, creating piles of solidified magma.

Is basaltic lava more viscous than andesitic lava?

In more humid areas, the basalt has a reddish color because of the breakdown of the iron minerals to make rust. In contrast to basaltic lava flows, andesitic lava flows have a higher SiO₂ content of 52–62%, which makes the lava more viscous.

Why is andesitic lava viscous?

Andesitic lava is an example of a high viscosity lava whereas balastic lava has a low viscosity, so is more runny. High silica content in the andesitic lava contributes to causing this high viscosity and low silica content in the basaltic lava means it is of a lower viscosity.

Is andesitic lava thick or thin?

ANDESITIC LAVA

These viscous lavas have relatively high aspect ratios (thickness/area), generally > 1/100, and some are thick enough to form as lava domes. Andesite commonly erupts from stratovolcanoes, where they form small-volume flows that typically advance only short distances down the flanks of a volcano.

What is an andesitic volcano?

Andesite is a gray to black volcanic rock with intermediate silica content, typical for lava domes and stratovolcanoes in subduction zones. Andesite is an igneous volcanic rock containing between about 52 and 63 weight % silica (SiO2).

What is andesitic lava like?

lava. Lavas of andesitic or intermediate composition commonly form a somewhat different type of flow, known as a block lava flow. These resemble aa in having tops consisting largely of loose rubble, but the fragments are more regular in shape, most of them polygons with fairly smooth sides.…

How is andesitic magma produced?

Andesitic magma is formed through wet partial melting of the mantle. The mantle under the ocean has contact with water. When subduction, or continental plates pulling away from one another, occurs, the mantle will heat up and water is pushed into it.

Is basaltic lava thick or thin?

Although these lava flows are often more viscous, and typically thicker, than pahoehoe lavas they tend to advance at greater rates. Their flow fronts can vary from two meters to as much as twenty meters thick. Their forward motion is similar to the movement of a tractor tread.

Is basaltic lava runny?

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.

What is a basaltic lava flow?

Lesson Summary. Basaltic lava, or mafic lava, is molten rock enriched in iron and magnesium and depleted in silica. Basaltic magmas are formed by exceeding the melting point of the mantle either by adding heat, changing its composition, or decreasing its pressure.

What are the characteristics of basaltic lava?

Basalt is erupted at temperatures between 1100 to 1250 ° C. Volcanic rock (or lava) that characteristically is dark in color (gray to black), contains 45 to 53 percent silica, and is rich in iron and magnesium. Basaltic lavas are more fluid than andesites or dacites, which contain more silica.

What are the characteristics of andesitic magma?

It ranges in temperature from about 1000^oC to 1200^oC (1832^oF to 2192^oF). Andesitic magma has moderate amounts of these minerals, with a temperature range from about 800^oC to 1000^oC (1472^oF to 1832^oF). Rhyolitic magma is high in potassium and sodium but low in iron, magnesium, and calcium.

What type of volcano has andesitic magma?

stratovolcanoes

Shield volcanoes are formed by basaltic magma, typically above a mantle plume, whereas the stratovolcanoes (sometimes referred to as composite volcanoes) are formed by andesitic/rhyolitic magma.

Is basalt a soft rock?

Basalt. Basalt is a hard, black volcanic rock. Basalt is the most common rock type in the Earth’s crust.

Is sandstone hard or soft?

Most sandstones are made up largely of quartz grains, because quartz is a very hard and chemically-resistant mineral. Quartzite is a name given to very hard, pure quartz sandstones. Many sandstones contain some grains of other minerals like calcite, clay, or mica.

Is marble a sedimentary rock?

The main difference between limestone and marble is that limestone is a sedimentary rock, typically composed of calcium carbonate fossils, and marble is a metamorphic rock.

What kind of rock is limestone?

sedimentary rock

Limestone is a sedimentary rock composed principally of calcium carbonate (calcite) or the double carbonate of calcium and magnesium (dolomite). It is commonly composed of tiny fossils, shell fragments and other fossilized debris.

What type of rock is coal?

Coal is a black sedimentary rock that can be burned for fuel and used to generate electricity. Coal is the leading source of energy in the United States. Coal is a black or brownish-black sedimentary rock that can be burned for fuel and used to generate electricity.

What type of rock is magnesite?

Sedimentary Rock

Magnesite as a Sedimentary Rock–Type I. Carbonate of magnesia occurs as a sedimentary rock at Atlin, B.C., and in Kern Co., California.

Does Obsidian exist?

obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass.

Is Crying obsidian real?

This purple block is a rare, hard block that is created when water is placed on a Lava source block. The Crying obsidian can only be mined using a diamond or Netherite pickaxe and they usually take a slightly shorter period of time to mine than any regular obsidian.

Is rainbow obsidian rare?

Despite being considerably rare, rainbow obsidian isn’t unreasonably expensive within the crystal market. A small piece of this stone goes a long way, so you don’t necessarily have to be investing in the biggest chunk you can find, so that you can reap the healing properties.

Is obsidian sharper than diamond?

Surprising Things about Obsidian

Surprisingly, the edge of a piece of obsidian is superior to that of a surgeon’s steel scalpel. It is 3 times sharper than diamond and between 500-1000 times sharper than a razor or a surgeon’s steel blade resulting in easier incisions and fewer microscopic ragged tissue cuts.

Can a diamond cut obsidian?

The best saw to use to cut or slice Obsidian is a Diamond Saw. Obsidian is easy to saw and makes the ideal stone to cut and polish.