Swinden Quarry

Also within

North Yorkshire County YORKSHIRE DALES National Park

Condition (Natural England)

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Carboniferous · Rock Type: Limestone

Description

Description The area to the north east of the village of Cracoe has long been famous for the development of knoll reefs within the Lower Carboniferous succession. There has been much discussion over the mode of formation of the reefs ranging from largely hydrodynamically controlled processes to those with significant biological input. Whereas the majority of the knoll reefs are preserved with their external morphology intact, only at Swinden Quarry has a reef mound been dissected by quarrying to show its internal structure. The features exposed include reef core thickly bedded limestones with a sparse fauna and reef margin deposits with an abundant shelly fauna including large brachiopods, productids, spiriferids, etc., varied gastropods and occasional bivalves. In addition, two significant marker horizons include a thick intensely bedded level of crinoidal limestone, with rare echinoid fragments and an iron rich band with large colonial rugose corals Lithostrotion. The large scale of the quarry exposures facilitates study of the lateral variation of beds, inwhich rapid thickening and thinning is locally prominent. It is only through detailed study of these variations that it will be possible to attempt to recognise the key processes involved in the development of the reef mounds of the District. Swinden Quarry is therefore of fundamental importance to future studies of the famous Cracoe Reef Mound complex, its origins, development and palaeoecology.