Siderite Sandstone from the cliff at Long Bight, Whitby, UK

Siderite sandstone PPL: The Dogger Formation forms the base of the Middle Jurassic in the Cleveland basin. It is a complex unit, varying from shales to ooidal ironstones. The thin sections show that it consists of quartz grains "suspended" in a matrix of very fine grained siderite.

Siderite sandstone XPL: The comparatively large grain to the left is 1mm in length (north to south). It appears to be a quartzite clast consisting of interlocking quartz crystals. Note the large quartz on the extreme right. The whole of the thin section shows two distinct sizes of quartz grains; those around 1mm, and others around 0.2mm suggesting different provenances. 

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