Welsh Borderland Geological Framework Project : the geology and applied geological issues of the region around Knighton, Powys : a scoping study

This presents a review of the extent of geological knowledge and available analogue and digital data for the region around Knighton, Powys (Figure 1). Although a key consideration underlying this report is the lack of modern geological mapping for the greater part of 1:50 000 Geological Sheet 180 (Knighton), the wider context of new BGS and NERC strategies requires that it considers the geology of the region and the resulting issues more broadly. Thus, the scoping study considers the geology within relevant parts of the upper catchments of the rivers Severn and Wye, as broadly delimited in Figure 1. Although relatively limited in age range, the geology is complex both lithostratigraphically and structurally. Because of this and time constraints, this report only discusses the geology at a level of detail sufficient to highlight the most important geological issues, rather than aiming to present a fully comprehensive account. The region studied includes the Knighton district, but also includes the western part of the Ludlow district (181; provisional edition), with specific regard to the Silurian and lower parts of the Devonian succession. The region also overlaps with parts of the other 8 adjacent 1:50 000 geological maps (Figure 1). Matters in this regard are simplified because of the recent, high quality geological data and mapping available for Llanidloes (164), Montgomery (165), Rhayader (179) and Builth Wells (196). The map for the Hay-on-Wye (197) district is provisional and is known to have problems with the geology as currently defined. Finally, the region has minor overlaps onto Church Stretton (166), published in the 1960’s and Hereford (198). The report provides a compilation of existing data, considers the scientific and applied issues arising from the review of the geology and databases, and proposes strategies for updating the geological database for the region