GeologyTechnical Data Sheet Doulting Stone
The stone is from the Inferior Oolite of middle Jurassic age; approximately 170 million ago. Unlike the stone extracted centuries ago, the currently available is rarely oolitic. The matrix is comprises of fragments of older Carboniferous (or perhaps Liassic) limestones which were eroded and later re-deposited, and, fine to coarse shell fragments. this matrix is cemented with calcium carbonate (calcite) resulting in a crystalline and coarsely granular appearance. Occasionally, complete or near complete, fossil sheels or corals may be found; this however, is quite rare. These characteristics distinguish Doulting Stone from other Jurassic limestones. It is creamy-brown or grey in colour with a regular and uniform texture.
This photograph depicts the stone at about 1:1 scale
Doulting stone would have been deposited as sediments in fairly shallow coastal seas. This is evidenced by being comprised of rock and shell fragments as described above. This is a strong indicator that the environment was controlled by powerful sea or ocean current and, tidal forces. Storm surges and consequential deep scouring of the shallow coastal waters caused severe fragmentation of the matrix components. Rapid burial under a new sediment load then preserved the fragments as they are now seen. The sedimentary sequence at Doulting appears to be unique, in that this exact rock type is seen nowhere else in the Mendip Hills region.
The sedimentary deposition sequence of the Jurassic limestones were strongly controlled by the Variscan mountain building episode. The remnants of this being the Mendip Hills. Whilst the mountains were being built, the basin areas in the region were subsiding. This is evidenced by the Jurassic sequences off-lapping the Carboniferous limestones. This is seen clearly in Vallis Vale. The Jurrassic limestones lie unconformably upon the wave cut platform which is represented by the Carboniferous limestones. This can be seen at its' best at the De La Beche unconformity in Vallis Vale
Doulting Stone Quarry
Chelynch Road, Doulting,
Shepton Mallet, Somerset BA4 4PZ
Phone: 01749 880608. Fax: 01749 880703