John Michael Hancock (10 August 1928 – 4 March 2004),[1] known professionally as Jake, was a geologist with particular interests in chalk and the Cretaceous Period.

Hancock was born on 10 August 1928 in Salisbury, Wiltshire, educated at Dauntsey's School near Devizes and was a national serviceman in the Royal Air Force between 1947 and 1949, before going to Queens' College, Cambridge, to read geology and petrology as an undergraduate.

His thesis was entitled The marginal facies of the British Chalk and in 1955 he joined the junior academic staff at King's College, London.

His contributions included over 110 scientific papers in English and French and a pursuit of the study of the relationship between geology and viniculture.

He was the subject of a memorial volume of the Proceedings of the Geologists' Association in 2006 (Vol 117, Part 2), on which some of this article is based.