Dreghorn Link

Dreghorn Link

Dreghorn Link connects Redford to the City Bypass. It has two 300m-long road cut exposures that show a type example of ‘Upper Old Red Sandstone’ of latest Devonian age (359 million years old). The sandstone layers demonstrate a changing environment both during and after their formation. Individual beds representing different positions in a river system were formerly deposited horizontally and have since been tilted toward the south-west. They show grain size variation, ‘cross-bedding’ (a signature of water-controlled deposition), changing bed thickness and erosional contacts between. Towards the south of the cutting, 70m beyond the footbridge, a fault is preserved with associated features including quartz veining where high pressure fluids percolated through weaknesses generated by the faulting. A definitive feature of faulting is exposed, called ‘slickensides’. These are scrape marks left by rocks sliding past each other and can give a geologist the exact sense of movement of the fault.