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granitic magmas contain more silica than basaltic magmas.
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∙ 13y ago
Granitic magmas are thicker than basaltic magmas because they have higher silica content, which increases viscosity. The higher silica content leads to stronger bonding between the silica tetrahedra, making it more difficult for the magma to flow. Basaltic magmas, on the other hand, have lower silica content and are less viscous, allowing them to flow more easily.
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How would you compare and contrast basaltic and granitic magmas?
Basaltic magmas have a lower silica content and higher temperature than granitic magmas. Basaltic magmas are more fluid and tend to erupt more explosively, while granitic magmas are more viscous and can lead to explosive eruptions due to gas buildup. Additionally, basaltic magmas form oceanic crust, while granitic magmas form continental crust.
Why are granitic igneous rocks light in color?
granitic igneous rocks are light colored because of a lower density than basaltic rocks
What type of eruptions do mafic magmas cause?
Basaltic magmas are associated with fissure eruptions creating lava flows spilling out from cracks in the crust. This is because basaltic magmas are more viscous and contain a lower concentration of gases than rhyolitic magma and therefore are unable to build up sufficient pressure to produce explosive eruptions.
Why are andesitic and granitic rocks confined to the continents and ocean margins but absent from deep ocean basins?
Andesitic and granitic rocks are formed through the cooling and solidification of magma in continental crust, which is thicker and less dense than oceanic crust. Due to their lower density, these types of rocks are more buoyant and tend to float on top of the denser basaltic oceanic crust. As a result, andesitic and granitic rocks are primarily found on continents and their margins, while deep ocean basins are mainly composed of basaltic rocks.
What percentage of lava on Earth is basaltic?
Volumetrically, most lava is of basaltic composition. Basaltic melts have overall lower gas contents and are more fluid than their andesitic-to-rhyolitic counterparts. Their higher fluidity (lower viscosity) is a product of their lower SiO2 (silica) contents. When gases exsolve from basaltic melts they are allowed to rise unimpeded through the fluid magma without a significant build up of gas pressure. This results in relatively calm, nonexplosive eruptions, and a preponderance of lava. In contrast, when gases exsolve from felsic magmas, their upward mobility is impeded by the high viscosity of the melt. This results in the buildup of gas pressure, which generates explosive eruptions associated with a preponderance of pyroclastic ejecta. The low viscosity of basaltic lavas allows them to be extruded over great distances, often producing high-volume lava flows with low aspect ratios (ratio of thickness to area). Under the right conditions, de-gassed felsic magmas can also erupt lava in a nonviolent manner. However, felsic lavas tend to be much thicker than basaltic lavas and have much higher aspect ratios.source:www.geology.sdsu.edu
How would you compare and contrast basaltic and granitic magmas?
Basaltic magmas have a lower silica content and higher temperature than granitic magmas. Basaltic magmas are more fluid and tend to erupt more explosively, while granitic magmas are more viscous and can lead to explosive eruptions due to gas buildup. Additionally, basaltic magmas form oceanic crust, while granitic magmas form continental crust.
Will rhyolitic magmas erupt at lower temperatures than basaltic magmas?
Yes, rhyolitic magmas are several hundred °C colder than basaltic magmas. This is because the melting point of a rhyolitic magma is much lower than that of basaltic magma. Instead of heating up rhyolitic magma much above its melting point it will ascend and either crystallize in the Earth's interior as a pluton or erupt.
Why are granitic igneous rocks light in color?
granitic igneous rocks are light colored because of a lower density than basaltic rocks
Why are granitic igneous rocks lighter in color than basaltic rocks?
Granitic igneous rocks are lighter in color than basaltic rocks because they contain more quartz and feldspar minerals, which are typically light in color. Basaltic rocks, on the other hand, contain more dark-colored minerals like pyroxene and olivine, giving them a darker color.
How is continental lithosphere different oceanic lithosphere?
Continental lithosphere is thicker and less dense than oceanic lithosphere. Continental crust is primarily composed of granitic rock while oceanic crust is composed primarily of basaltic rock.
What type of eruptions do mafic magmas cause?
Basaltic magmas are associated with fissure eruptions creating lava flows spilling out from cracks in the crust. This is because basaltic magmas are more viscous and contain a lower concentration of gases than rhyolitic magma and therefore are unable to build up sufficient pressure to produce explosive eruptions.
Why are andesitic and granitic rocks confined to the continents and ocean margins but absent from deep ocean basins?
Andesitic and granitic rocks are formed through the cooling and solidification of magma in continental crust, which is thicker and less dense than oceanic crust. Due to their lower density, these types of rocks are more buoyant and tend to float on top of the denser basaltic oceanic crust. As a result, andesitic and granitic rocks are primarily found on continents and their margins, while deep ocean basins are mainly composed of basaltic rocks.
How is basaltic lava different from granitic lava?
Basaltic lava is far less viscous, has less silica, erupts at a higher temperature and is denser than granitic lava (properly called rhyolitic lava when it is on the surface). Basaltic lava is composed primarily of pyroxenes and calcium rich plagioclase with small amounts of olivine. Rhyolitic lava primarily contains alkali feldspars and quartz.
How do scientists determine mantles is denser than the crust?
The mantle is composed of basaltic rock, the crust is composed mostly of granitic rock. Basalt is denser than Granite.
What is the relationship in the silicon content and the viscosity of magma?
The higher the silicon content in magma, the higher its viscosity. This is because silicon-rich magma tends to form more complex and tightly bonded silica tetrahedra, which make it more resistant to flow. As a result, magma with higher silicon content will be more viscous and flow more slowly compared to magma with lower silicon content.
Why do granitic felsic magmas usually crystallize before reaching earth's surface?
Felsic magma is very viscous, so if often gets "stuck" in plutons rather than erupting.
How is continental lithosphere different from oceanic lithosphere?
Continental plates are thicker and less dense. Continental plates are mainly granitic in composition. Oceanic plates are mainly basaltic in composition. The rock of continental plates is on average, much older than the rock of the oceanic plates. The oceanic plate underlies the oceans, and the continental plate makes up the land masses. Continental plates do not subduct at convergent plate boundaries.
