Basement (geology)

In geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover. "The surface beneath which no sedimentary rock is found".Kearey, Philip 2001. The new Penguin dictionary of geology. 2nd ed, London: Penguin. 

More generally, it is any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin. In the same way the sediments and/or sedimentary rocks on top of the basement can be called a "cover" or "sedimentary cover".

 References 

Category:Geology