Kelso Volcanic Formation
Kelso Volcanic Formation (KT), Carboniferous, Midland Valley of Scotland
Kelso Volcanic Formation is part of the Inverclyde Group
Name
Named after the town of Kelso, with early references to the ‘Kelso traps’ (see Eckford and Ritchie, 1939[1]) and Kelso Lavas (McRobert, 1925[2]).
Lithology
The Kelso Volcanic Formation comprises olivine basalts and subordinate tuffs and sedimentary strata (volcaniclastic sandstone).
Genetic interpretation
The formation formed during the main initial phase of extensional faulting associated with development of the Northumberland Trough.
Stratotype
Partial type sections occur in the Blackadder Water at Lintmill (NT 7338 4636) (which includes the lowest lava), Lintmill Railway Cutting (NT 727 463 to 736 466) east of Greenlaw (see Williamson in Stephenson et al., 2003[3]), the Eden Water below Girrick (NT 6676 3724), and the River Tweed south of Makerstoun House (NT 6736 3154). See Eckford and Ritchie (1939)[1] for further reference to these local sequences in the formation.
Lower and upper boundaries
The base of the formation conformably overlies the red sandstones, siltstones and conglomerates of the Kinneswood Formation in Berwickshire (Figure 8, Column 12). The top of the formation is conformable with the base of the ‘cementstone’-bearing strata of the Ballagan Formation.
Thickness
Up to 150 m.
Distribution and regional correlation
Berwickshire. Correlated with the Birrenswark Volcanic Formation of the Solway Basin.
Age
Mid Tournaisian (Courceyan)
References
- ↑ 1.0 1.1 Eckford, R J A, and Ritchie, M.1939.The igneous rocks of the Kelso district.Transactions of the Edinburgh Geological Society, 13, 464–472.
- ↑ McRobert, R W.1925.Igneous rocks of Teviot and Liddesdale.Transactions of the Edinburgh Geological Society, Vol.11, 86–103.
- ↑ Stephenson, D, Loughlin, S C, Millward, D, Waters, C N, and Williamson, I T.2003.Carboniferous and Permian Igneous Rocks of Great Britain North of the Variscan Front.Geological Conservation Review Series, No. 27. (Peterborough: Joint Nature Conservation Committee.)