Roddam Dene Conglomerate Formation
Roddam Dene Conglomerate Formation (RDCO), Carboniferous, Midland Valley of Scotland
Roddam Done Conglomerate Formation is part of the Inverclyde Group
Named after the type section (see Stratotype below) (Cossey at al., 2004).
Conglomerate, in thick and very thick beds; reddish coloured; subangular to subrounded clasts of pebble- to boulder-grade set in a clay-rich sandstone matrix; matrix supported to clast supported. Clasts predominantly of andesite, derived from the Cheviot Volcanic Formation, but also rare clasts of Silurian mudstone and greywacke sandstone and Cheviot granite. There are minor intercalations of mudstone, sandstone and siltstone at the top.
The type section is Roddam Dene, south of Wooler, Northumberland (NU 018 207 to 025 207) where about 170.m of dominantly conglomerate, with interbedded sandstone, mudstone, and calcareous mudstone are seen in three fault-bounded units (see Cossey et al., 2004, pp. 149–151).
Lower and upper boundaries
The lower boundary is not seen, but it is thought to overlie the Cheviot Volcanic Formation unconformably.
The upper boundary of the formation is not seen, but it is believed to be overlain conformably by rocks of the Ballagan Formation (formerly the Cementstone Group of Northumberland).
About 170 m seen.
Distribution and regional correlation
Limited to the eastern flanks of the Cheviot Block, Northumberland.
- Cossey, P J, Adams, A E, Purnell, M A, Whiteley, M J, Whyte, M A, and Wright, V P.2004.British Lower Carboniferous stratigraphy.Geological Conservation Review Series, No 29. (Peterborough: Joint Nature Conservation Committee.)