Roddam Dene Conglomerate Formation

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Roddam Dene Conglomerate Formation (RDCO), Carboniferous, Midland Valley of Scotland

Roddam Done Conglomerate Formation is part of the Inverclyde Group

Name

Named after the type section (see Stratotype below) (Cossey at al., 2004[1]).

Lithology

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.

Stratotype

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[1]).

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).

Thickness

About 170 m seen.

Distribution and regional correlation

Limited to the eastern flanks of the Cheviot Block, Northumberland.

Age

Tournaisian.

References

  1. 1.0 1.1 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.)