Preglacial landscapes
The selectivity of glacial erosion in the Cairngorms and the surrounding areas has left many traces of the older, pre-Quaternary landscape. It is, of course, a granite landscape and one in which there is strong structural control on relief. At the scale of the entire massif, the major valleys are aligned preferentially along faults and zones of hydrothermal alteration. Local detail is provided by joint systems - these define zones of relative weakness and resistance to weathering and erosion. Curvilinear sheet joints often define the surface slopes and give rise to the many low domes to be found in the mountains. This varied substrate was etched by weathering under warm temperate conditions in the late Tertiary. It seems that traces of these weathering mantles are absent from the high Cairngorms but deep weathering is preserved to the south in the Gaick Forest.