What is basaltic magma?
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 is the composition of 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. Nepheline or leucite may associate or proxy the feldspar giving rise to verities with special names.
What happens when basaltic magma is formed?
Basaltic magma is formed through dry partial melting of the mantle. This causes the temperature in the earth’s mantle to rise, which causes the mantle to partially melt. The partial melt contains both liquid and crystals that need a higher temperature to melt.
What is the difference between andesitic and basaltic lava?
Both lavas are formed at different plate boundaries which is why they have different silica contents: the basaltic lava forms from the hot mantle material at constructive plate boundaries and hotspots whereas the andesitic lava forms at destructive plate boundaries from melting crust.
What is the difference between vesicular basalt and basalt?
Scorias are basaltic rocks with numerous small gas bubbles. Vesicular basalts are basaltic rocks having relatively few, relatively large gas bubbles. Vesicular basalt is more dense than scoria (some scorias will float on water; vesicular basalts won’t do that).
What is the difference between vesicular basalt and scoria?
Lava Flows and Vesicular Basalts These trapped gas bubbles are known as vesicles. If the upper portion of a lava flow contains a large concentration of vesicles, it is often called “scoria” or “vesicular basalt.” This material often has fewer vesicles and a higher specific gravity than the scoria of lapilli.
What is the importance of basalt?
Basalt is used for a wide variety of purposes. It is most commonly crushed for use as an aggregate in construction projects. Crushed basalt is used for road base, concrete aggregate, asphalt pavement aggregate, railroad ballast, filter stone in drain fields, and may other purposes.
What is the texture and composition of basalt?
Basalt is rich in iron and magnesium and is mainly composed of olivine, pyroxene, and plagioclase. Most specimens are compact, fine-grained, and glassy. They can also be porphyritic, with phenocrysts of olivine, augite, or plagioclase. Holes left by gas bubbles can give basalt a coarsely porous texture.
Is basalt a ceramic?
Among the iron, silicates are the basalt glass-ceramics. Products obtained from fused rocks have a large market and can be considered the precursors of glass-ceramic .
What type of eruption does basaltic magma most likely produce?
There are two major groupings of eruptions: effusive and explosive. Effusive eruption differs from explosive eruption, wherein magma is violently fragmented and rapidly expelled from a volcano. Effusive eruptions are most common in basaltic magmas, but they also occur in intermediate and felsic magmas.