TARDISes released chronon energy (PROSE: Attack of the Snowmen) and Magnus Greel's arrival in the time cabinet in the 1800s via a zygma beam caused massive discharges of chronon radiation which flowed along the Earth's telluric currents, forming the Dragon Paths.
Time Lord bodies were apparently sustained by chronon energy, as the Sixth Doctor was weakened to the point of death when most of his chronon energy was lost during his confrontation with the Lamprey. (PROSE: Spiral Scratch)
Weeping Angels fed on time energy created when they threw their victims into the past to live off of the energy of their "lost days." (TV: Blink, The Time of Angels/Flesh and Stone, The Angels Take Manhattan)