Arthur Holmes FRS FRSE (14 January 1890 – 20 September 1965) was an English geologist who made two major contributions to the understanding of geology.

He pioneered the use of radiometric dating of minerals, and was the first earth scientist to grasp the mechanical and thermal implications of mantle convection, which led eventually to the acceptance of plate tectonics.

[2][3] He was born in Hebburn, County Durham, near Newcastle upon Tyne, the son of David Holmes, a cabinet-maker, and his wife, Emily Dickinson.

After she died in 1938, Holmes in the following year married Doris Reynolds, a geologist who had joined the teaching staff at Durham.

1912 saw Holmes on the staff of Imperial College, publishing his famous book The Age of the Earth in 1913 in which he argued strongly for radioactive methods compared with methods based on geological sedimentation or cooling of the earth (many people still clung to Lord Kelvin's calculations of less than 100 Ma).

[1] In the following year he was appointed to the chair of geology at the University of Edinburgh, following the death of Prof Thomas James Jehu, which post he held until retirement in 1956.

[15] Holmes championed the theory of continental drift promoted by Alfred Wegener at a time when it was deeply unfashionable with his more conservative peers.

One problem with the theory lay in the mechanism of movement, and Holmes proposed that Earth's mantle contained convection cells that dissipated radioactive heat and moved the crust at the surface.