What is basanite rock?
Basanite, extrusive igneous rock that contains calcium-rich plagioclase feldspar (usually labradorite or bytownite), feldspathoid (usually nepheline or leucite), olivine, and pyroxene (titanaugite). Basanites and tephrites occur as gray to black rocks in sheets and flows.
How is Tephrite formed?
A tephrite is an igneous rock of basaltic character that generally occurs as lava flows, but occasionally as minor intrusions. Its essential constituents are calcic plagioclase and clinopyroxene in association with nepheline, leucite, or analcime.
How is Phonolite formed?
Formation. Unusually, phonolite forms from magma with a relatively low silica content, generated by low degrees of partial melting (less than 10%) of highly aluminous rocks of the lower crust such as tonalite, monzonite and metamorphic rocks.
Is Basanite a basalt?
Essentially, the mineralogy is that of a basalt, with the addition of a feldspathoid mineral and olivine. Varieties of basanites are defined by the type of feldspathoid mineral present to give nepheline-basanite, analcite-basanite, and leucite-basanite. These rocks are found in close association with alkali basalts.
Where is Trachyte found?
Trachyte is common wherever alkali magma is erupted, including in late stages of ocean island volcanism and in continental rift valleys and above mantle plumes. Trachyte has also been found in Gale crater on Mars.
What is Aplite used for?
Also known as haplite, aplite is an intrusive igneous rock that chiefly consists of quartz and feldspars. Fine-grained and granitic, the material is sometimes utilized in the process of glassmaking. Aplite is light in color and exhibits a granular texture, similar to that of sugar.
What type of rock is quartzite?
quartzite, sandstone that has been converted into a solid quartz rock. Unlike sandstones, quartzites are free from pores and have a smooth fracture; when struck, they break through, not around, the sand grains, producing a smooth surface instead of a rough and granular one.
What type of rock is Phonolite?
phonolite, any member of a group of extrusive igneous rocks (lavas) that are rich in nepheline and potash feldspar. The typical phonolite is a fine-grained, compact igneous rock that splits into thin, tough plates which make a ringing sound when struck by a hammer, hence the rock’s name.
How is Basanite different from tephrite and nephelinite?
Basanite is again distinguished from tephrite by its normative olivine content and from nephelinite by a normative albite content of over 5% and a normative nepheline content under 20%.
What kind of rock is a basanite rock?
Basanite ( /ˈbæsənaɪt/) is an igneous, volcanic (extrusive) rock with aphanitic to porphyritic texture.
What kind of minerals are found in tephritic rocks?
Click the show button to view. Tephritic rocks (fine grained, very silica-poor, basaltic rocks), with felsics comprising 10-60% foids and alkali feldspar /total feldspar <0.1, >10% olivine. Tephrite is similar but contains little or no olivine.
Is the black chert the same as basanite?
Basalt is similar but contains little or no foids. Not to be confused with bassanite, the mineral, or basanite (chert), the black chert. This section is currently hidden.