"Bárðarbunga is unique in that it is an unusually large volcanic system, partly covered by a glacier, and several scenarios are possible. Magma intrusions, or dyke formations, from the caldera ...

(1) the Plutonic rocks; (2) the Dyke rocks (Ganggesteine); and (3) the Volcanic or Effusive rocks. Unable to free himself entirely from the idea that geological age ought to be an essential factor ...