Keith Emerson, founding member and keyboardist of prog rock supergroup Emerson, Lake & Palmer, passed away on Friday at the age of 71. Billboard reports that Emerson died of a self-inflicted gunshot wound to the head and his death has been ruled a suicide by Santa Monica Police.br TMZ reports that Emerson had been battling depression as well as a degenerative nerve issue in his right hand that made it increasingly difficult for him to perform music.