Evidence from apatite fission track analysis for the post-Devonian burial and exhumation history of the northern Highlands, Scotland

Devonian and older rock samples from outcrops in the northern Scottish High lands have undergone protracted cooling since they reached palaeotemperatur es of similar to 110 degrees C or more in the Late Palaeozoic to Early Meso zoic. The results not only suggest that the northern Highlands region has e xperienced kilometre-scale exhumation since the Late Palaeozoic, but also t hat Devonian and possibly Permo-Carboniferous sedimentation was probably mo re extensive than current outcrop patterns would imply. A Permian outcrop s ample from the Minches Basin reached a maximum palaeotemperature of 70-90 d egrees C prior to the onset of cooling in the Early Tertiary, while data fr om Devonian and older samples suggest an acceleration in the rate of coolin g in the Early Tertiary. The magnitude of Early Tertiary palaeotemperatures on the mainland adjacent to the Inner Moray Firth (IMF) indicate similar a mounts of Tertiary exhumation to those derived from compaction analyses for the IMF. However, to the west, the magnitude of Tertiary cooling cannot be solely ascribed to exhumation and a contribution of heating due to hydroth ermal effects and/or elevated heat flow associated with the Tertiary Igneou s Complex may also need to be invoked. (C) 1999 Elsevier Science Ltd. All r ights reserved.