Metasomatism in the basalt of Haddenrig quarry near Kelso and the veining of the rocks exposed there

Abstract

Haddenrig (Haddon Rig) quarry is situated three miles east of Kelso in Roxburghshire, near the road from Kelso to Mindrum in Northumberland. The rock quarried is marked on the Geological Survey Map (Scotland, Sheet 26) as a basalt intrusive into the Lower Carboniferous lavas (Kelso traps). The absence of exposed contacts excludes any direct field evidence of its intrusive character, but the appearance of the fresh basalt from the quarry suggests that it belongs to a sill or a plug, as it is in many ways similar to other intrusive basalts of the Kelso district. The evidence of the orientation of the felspar laths in the basalt is not entirely conclusive. With the exception of the northern part of the quarry where the orientation is vertical, elsewhere it is more or less horizontal. This suggests a sill. The vertical orientation of laths in the northern part of the quarry may be due either to the presence of a feeding channel or to eddies in the sill.