Table of Contents
- 1 What is magma with a low silica content called?
- 2 What type of rock is dark with low silica content?
- 3 Which type of mineral has a lower amount of silica and is dark-colored?
- 4 What is felsic lava?
- 5 What is a rock that is dark-colored has lower silica contents and is rich in iron and magnesium?
- 6 Why do some types of magma form igneous rocks that are dark colored and dense?
- 7 Which rock is lower in silica mafic or felsic?
- 8 How does magma with low silica content erupt?
- 9 What makes mafic magma different from other magmas?
- 10 Why are some types of magma darker than others?
What is magma with a low silica content called?
MAGMA COMPOSITION AND ROCK TYPES
| SiO2 CONTENT | MAGMA TYPE | VOLCANIC ROCK |
|---|---|---|
| ~50% | Mafic | Basalt |
| ~60% | Intermediate | Andesite |
| ~65% | Felsic (low Si) | Dacite |
| ~70% | Felsic (high Si) | Rhyolite |
What type of rock is dark with low silica content?
Mafic rocks such as gabbro are dark-colored, have lower silica contents, and are rich in iron and magnesium.
What type of magma is dark in color?
Lava (magma that has erupted onto the Earth’s surface) is visually mesmerizing – as the molten rock flows downhill, lava exposed to the air cools to a deep black color, while the molten rock beneath glows bright orange. dark-colored volcanic rock.
Which type of mineral has a lower amount of silica and is dark-colored?
Ultramafic rocks have extremely low silica content (less than 45%) and contain large amounts of iron and magnesium. They are usually dark-colored, but high olivine content can lend green shades to the rock. Other rare colors can be found. An example of ultramafic rock is Peridotite (intrusive).
What is felsic lava?
Felsic lavas are low temperature lavas because lower temperatures are required to keep felsic minerals molten (and if it was hotter it would have incorporated more iron and magnesium in comparison to silica). So, mafic lavas are hot , low in silica and volatiles, and have relatively low viscosity.
Which type of magma contains the most silica?
Felsic magmas
Felsic magmas are higher in silica and contain lighter colored minerals such as quartz and orthoclase feldspar. The higher the amount of silica in the magma, the higher is its viscosity.
What is a rock that is dark-colored has lower silica contents and is rich in iron and magnesium?
basalt
basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in colour, and comparatively rich in iron and magnesium. Some basalts are quite glassy (tachylytes), and many are very fine-grained and compact.
Why do some types of magma form igneous rocks that are dark colored and dense?
igneous rocks that are dense and dark-colored. They form from magma that is rich in iron and magnesium and poor in silica.
How does silica affect the color of magma?
The more silica you have in a rock, the paler it tends to be. Felsic rocks have high silica content, because they contain lots of quartz and another mineral called feldspar. These are rocks like basalt, which is very darkly coloured.
Which rock is lower in silica mafic or felsic?
Mafic vs Felsic Since igneous rocks are characterised by silica content in them, mafic is the one with less silica content (approx. 45-55%) while felsic is the one with a greater silica content (approx. 70-90%).
How does magma with low silica content erupt?
Magma with low silica content is very fluid and easily erupts onto the surface through cracks and crevices at the surface. Over time the layers of lava build up a volcanic cone.
What kind of silica is found in igneous rocks?
All igneous rocks are made of the same major elements, but elemental ratios vary. The most significant variations are the amounts of silica (SiO 2) present (see table). Most igneous rocks contain between 45 and 65 wt% silica. They range from lower-silica basalt and gabbro to higher-silica rhyolite and granite.
What makes mafic magma different from other magmas?
Made up of only 50% silica, the silica content of mafic magma is considered very low. However, it does contain a lot of magnesium and iron, along with a low gas content and not very much gooiness.
Why are some types of magma darker than others?
The color is due to the amount of magnesium and iron in the magma, because both of these minerals are very dark in color. In addition, basalt is a very common rock found in the earth’s crust, and it is also found in the volcanic islands developed by hot spots.