Whats solidified magma in an extinct volcano?
Solidified magma in any setting is an igneous rock – which one depends on the composition of the magma and the grain size. The largest and deepest intrusions are called Batholiths, and they may consist of granite or other coarse-grained plutonic rocks like gabbro, diorite. When huge amounts of magma are released through long open cracks it is called a Large Igneous Province (L.I.P.). These usually consist of basaltic sheets. Basalt is a lava with a low viscosity – which means it flows easily. Plateau Basalts are a form of L.I.P. forming on Continents, and usually associated with rifted margins. Examples are the Deccan Traps in India, and the Karoo basalts in South Africa.
