Pyrolite is a term used to characterize a model composition of the Earth's mantle. This model is based on that a pyrolite source can produce mid-ocean ridgebasalts (MORB) by partial melting.[1][2] It was first proposed by Ted Ringwood (1962)[3] as being 1 part basalt and 4 parts harzburgite, but later was revised to being 1 part tholeiitic basalt and 3 parts dunite.[1][4] The term is derived from the mineral names PYR-oxene and OL-ivine.[5] However, whether pyrolite is entirely representative of the Earth's mantle remains debated.[6]