玄武岩是喷出岩的一种,也就是岩浆上升喷出地表冷却凝固所形成的岩石。它们在地壳中分布广泛,不论是地槽区地台区,也不论是在大陆或海洋都可以看到有大量玄武岩出露。岩石均为暗色,一般为灰黑色,矿物成分相当于辉长岩,往往具气孔构造、杏仁构造,有时还可见熔渣状构造、绳状构造 Basalt is a kind of rock that is sprayed out, that is, the rock formed by the cooling and solidification of the magma as it rises and falls from the surface. They are widely distributed in the earth’s crust, both in the terrain area and in the mainland or in the oceans, a large amount of basalt can be seen. Rocks are dark, usually gray-black, mineral composition is equivalent to gabbro, often with stomatal structure, almond structure, and sometimes also visible slag-like structure, rope-shaped structure