Some Aspects of Limestone Solution in the Bristol Region

at the bottom of deep profiles may represent the amount of solution which has occurred in the whole post-glacial period since mixing ceased. If this is correct then the maxi? mum rate of solution would be about 10 mm. of residue, which is equivalent to 50 cm. of limestone, in 10,000 years. This rate is of the same order as estimates based on rainfall and concentrations of calcium in drainage waters. The preservation of a con? tinuous layer of yellow clay beneath the loess in some of the shallow depressions of the plateau may be a result of frost-heaving penetrating to a lesser depth in these more protected situations. The chemical alterations of the minerals in the clay are likely to have been produced by exposure to temperatures rather higher than those of the present day and this would indicate weathering during an interglacial period. There is clearly a very strong case for believing that these deep superficial deposits have been preserved on the Derbyshire limestone because the region escaped the Newer Drift Glaciation. This suggests that if similar deeply weathered mantles ever existed in those limestone districts, such as the Craven Pennines and The Burren, which lie within the boundary of the Newer Drift, they were removed or partly re? moved to produce the bare limestone surfaces so characteristic of these areas today. In view of the slow rate of lowering of limestone surfaces by solution, variations in the depth to which this weathered mantle was planed down should still be clearly recognizable in the present morphology of the surfaces. The variations in pavement-form which would result from incomplete removal of the deeply weathered mantle are illustrated in Figure 7. These types of pavement do, in fact, occur widely in The Burren and Craven Pennines, and detailed study of their distribution in relation to topography and probable directions of ice flow would be of very great interest

Archaeology · Geochemistry · Geography · Geological Modeling and Analysis · Geology · Geology and Paleoclimatology Research · Landslides and related hazards

• Limestone Ranges of the Fitzroy Basin, Western Australia

  Daniel Smith, D Ingle Smith et al.•Geographical Journal•1964

  Add to list