Ballagan FormationName
93378Province: Not defined.
Geologic Age: Early Mississippian Epoch-Mid Mississippian Epoch
Other: Calcareous mudstone, mudstone and siltstone with subsidiary argillaceous, muddy limestone/cementstone/calcilutite, basaltic tuff, conglomerate, dolomitic limestone, dolostone, gypsum-stone, limestone and sandstone and trace anhydrite-stone and coal. Stratified bedrock. Occurs onshore. Deposited during the Courceyan Substage - to - Chadian Substage (Carboniferous Period) (358.9-344.5 Ma BP). Grey mudstones and siltstones, with nodules and beds of ferroan dolomite (cementstones), the beds generally less than 0.3m thick. Gypsum and, to a much lesser extent, anhydrite and pseudomorphs after halite occur. Desiccation cracks are common and the rocks commonly show evidence of brecciation during diagenesis. Both these features are associated with reddening of the strata. Where present, the restricted fauna is characterised by the bivalve Modiolus latus, but ostracods are more abundant. Thin sandstones are present in many areas, and thick localised sandstones are also now included in the formation. About 900m (maximum) in the West Lothian area, and up to 250m in the Northern England Province. Not seen in type section; elsewhere transitional on cornstone-bearing sandstones of Kinnesswood Formation (as at a depth of 224.8m in British Geological Survey East Dron Borehole (NO11NW/24; NO1360 1572)). The top is drawn at the top of the highest unit of mudstone and cementstone in any particular area. The Clyde Sandstone Formation usually overlies the Formation.
Usage: Current name
