Great Quarry SSSI Swindon [2 photos] in SU1583 :: Geograph Britain and Ireland

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Great Quarry SSSI Swindon

compiled by Brian Robert Marshall

From the Natural England website:

The site was formerly named Town Garden Quarries which, with Station Cutting,
comprised Town Garden Quarries and Station Cutting SSSI. The two are now
separate with Station Cutting renamed Old Town Railway Cutting, Swindon, SSSI.
Description and Reasons for Notification:

The section here includes the only exposure of Purbeck facies ‘Swindon Series’. It has long been famous for the richness of its molluscan faunas from the marine
Swindon Roach. These beds, of Portlandian age, comprise a suite of sediments
ranging in their depositional environment from freshwater and hypersaline lagoons to true marine shell beds and soil profiles. The site has been the subject of dozens of published accounts since the mid 19th century and is still the subject of active research. The channelled form and erosive pebbly bases which characterise the majority of the beds in this succession and the variety of environments exhibited make this by far the most complex Jurassic section in Britain. The north-western exposures of the quarry include deposits of approximately one metre’s depth, thought to be Wealden in age. Overlying Portlandian Swindon Flags, these putative Wealden beds comprise deposits of ferruginous sand, sandy ironstone and greenish clay. Their fauna (Corbula ssp.? Neomiodon? Viviparus and serpulids) appears to be of Purbeckian or prePurbeckian age, a conclusion supported by the petrography of the clays (low kaolinite, etc). Some of the sand laminae, however, carry appreciable quantities of Cornubian detritus (high tourmaline and tourmaline fine aggregates, etc) possibly recycled from the Permo-Trias through the Portland Beds. Other laminae contain mostly northern material (low K-feldspar, tourmaline, etc, kyanite > staurolite, higher microcline, plagioclase, garnet, sphene, etc), while mixtures and alternations of detritus from the west and north are additionally indicated. This is a key site for solving problems concerning the arrival date of Cornubian detritus, and the relations of the Purbeck-Wealden facies with their contemporary marine facies."

by Brian Robert Marshall

Created: Mon, 18 Oct 2021, Updated: Tue, 19 Oct 2021

2 images use this description: (all images taken in 2021)

SU1583 : Jurassic limestone, Quarry Wildlife Garden, The Quarries, Swindon by Brian Robert Marshall

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