Crinoidal limestone - Derbyshire
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Fact sheet
Description: 

Crinoidal limestone deposits found in Derbyshire, England were laid down during the Lower Carboniferous times prior to progradation of large deltas from the north, which formed the later Millstone Grits. At that time, the part of the UK that would become the English Peak District was the bed of a sub-tropical shallow continental shelf sea with a variety of life some of which has been preserved in this rock. The location of this sample was far from shore although the sea remained shallow and the water was rich in nutrients, producing the perfect conditions for the buildup of platforms of carbonate-rich rock. Crinoids were common in this shallow shelf environment during the Carboniferous and have been referred to as ‘Derbyshire Screws’ because of their abundance in the Peak District limestone. The thin section illustrates the coarse-grained, poorly sorted, well-cemented nature of this limestone rock. It contains bivalves, brachiopods, corals and crinoids in a fragmental matrix cemented by crystalline calcite (known as sparite). 

In Place
In Time
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Location description: 
Once a Week quarry, Monyash, near Buxton, Derbyshire
Accuracy:
Location precision: 
Good
Timescale:
Timescale: 
Carboniferous
Ma = Millions of years ago
In Focus
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Type: 
sedimentary
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