The mountains of North-East Greenland are not remnants of the Caledonian topography. A comment on Pedersen et al. (2012): Tectonophysics vol. 530-531, p. 318-330

Pedersen et al. (2012) suggest that the present-day mountains in North-East Greenland represent remnants of the original Caledonian topography modified during early rifting, and that the area has undergone slow, steady exhumation since ~ 250 Ma. They base this hypothesis on inverse modelling calibrated by new apatite fission-track data from samples of exposed Caledonian basement. However, apatite fission-track data on their own register only cooling and must be integrated with geological evidence to reveal episodes of reheating, reflecting re-burial. The well-documented geological record of North-East Greenland shows that the Caledonian mountains were obliterated as topographic features during the late Palaeozoic and provides clear evidence of a history involving episodic, post-Caledonian exhumation and re-burial. The high-grade metamorphic basement was at great depth during the Devonian and was exhumed to the surface before being reburied by up to 2 km of Upper Carboniferous and younger sediments. These sediments were then partially removed during renewed, Early-Middle Jurassic exhumation that led to the formation of a low-lying landscape which eventually subsided and was buried below a km-thick cover of Middle Jurassic and younger sediments. This cover was then partially removed during later phases of uplift and exhumation that eventually led to the formation of the present-day relief in post-Jurassic times. The geological record in East Greenland is incompatible with the idea of slow, steady exhumation since the Caledonian orogeny.