 In the south it is defined by a group of epizonal intrusions and a few erosional remnants of eruptive rock.Farther north in the large Ha-Iltzuk and Waddington icefields, it includes two large dissected calderas called Silverthrone Caldera and Franklin Glacier Complex while the Queen Charlotte Islands to the northeast contain a volcanic formation ranging in age from Miocene to Pliocene called the Masset Formation.Although widely separated from each other, all Pemberton Belt rocks are of similar age and have similar magma compositions.