Editing Karst (section)

=== Paleokarst ===
Paleokarst or palaeokarst is a development of karst observed in geological history and preserved within the rock sequence, effectively a fossil karst. There are for example palaeokarst surfaces exposed within the Clydach Valley Subgroup of the [[Carboniferous Limestone]] sequence of [[South Wales]] which developed as sub-aerial [[weathering]] of recently formed limestones took place during periods of non-deposition within the early part of the period. Sedimentation resumed and further limestone strata were deposited on an irregular karst surface, the cycle recurring several times in connection with fluctuating sea levels over prolonged periods.<ref>{{cite book |last1=Howells |first1=M.F |title=British Regional Geology:Wales |date=2007 |publisher=British Geological Survey |location=Keyworth, Nottingham |isbn=978-085272584-9 |page=118}}</ref>