@eurocelticyankee,
You sent me searching, Irish.
Clinton Darryl "Clint" Mansell, (born 7 January 1963) is an English musician, composer, and former lead singer and guitarist of the band Pop Will Eat Itself.
After the disbanding of Pop Will Eat Itself in 1996, Mansell was introduced to film scoring when director Darren Aronofsky, hired him to score his debut film, π.Mansell then wrote the score for the next Aronofsky film, Requiem for a Dream, which has been well received. Its main composition "Lux Aeterna" has become extremely popular, appearing in a wide variety of advertisements and film trailers.
Stay With Me by him was one that I don't know, but it was haunting. Need to check out The Fountain as well