What is Basalt?
Basalt is an extrusive igneous rock, sometimes porphyritic, and is often both fine-grained and dense. Basalt in the tops of subaerial lava flows and cinders will often be highly vesiculated, imparting a lightweight “frothy” texture to the rock. The term basalt is often casually applied to shallow intrusive rocks with a composition typical of basalt, but rocks of this composition with a phaneritic groundmass should generally be referred to as gabbro. The crustal portions of oceanic tectonic plates are predominantly made of basalt. Unweathered basalt is frequently black to greenish-black in color, characterized by a preponderance of calcic plagioclase feldspars and pyroxene together with minor amounts of accessory minerals such as olivine. Basaltic cinders are often red. Glass may be present, particularly as rinds on rapidly chilled surfaces of lava flows, and is commonly (but not exclusively) associated with underwater eruptions. Amygdaloidal structure is common in relic vesicles and be
Basalt is a type of volcanic igneous rock that forms outside of the earth and is used for different purposes in construction. Discover how basalt is used as a major component of asphalt for roads with help from a science tutor and field biologist in this free video on basalt and chemistry. Expert: Brian Erickson Contact: Ericksontutoring.blogspot.com Bio: Brian Erickson is a tutor in math and science, as well as a field biologist.
